Safe Skies for Tomorrow: Aviation Safety in

a Competitive Environment

July 1988

NTIS order #PB89-114318
Recommended Citation:

U.S. Congress, Office of Technology Assessment, Safe Skies for Tomorrow: Aviation Safety

in a Competitive Environment, OTA-SET-381 (Washington, DC: U.S. Government Printing

Office, July 1988).

Library of Congress Catalog Card Number 88-600550

For sale by the Superintendent of Documents

U.S. Government Printing Office, Washington, DC 20402-9325

(order form can be found in the back of this report)
Foreword

It has been 10 years since the Airline Deregulation Act of 1978 transformed the rules

of the game for the commercial aviation industry. Although new entrants plunged into

the market throughout the early 1980s, the industry had consolidated markedly by late

1987. While many of the major players remain the same, computerized reservation systems

and hub and spoke scheduling have changed substantially the way airlines operate. Unquestionably, more Americans than ever are flying, and the safety record for commercial

aviation in the United States remains among the best in the world. Nonetheless, even after

many studies on the impacts of deregulation, questions linger about the adequacy of existing Federal safety policies and programs. The Committee on Public Works and Transportation and the Subcommittee on Government Activities and Transportation of the Government Operations Committee, both of the House of Representatives, asked the Office

of Technology Assessment to determine how well existing safety policies, regulations, and

technologies meet the government’s responsibility for ensuring safety in commercial aviation. The study was endorsed by the Senate Committee on Commerce, Science, and Transportation.

This report contains the results of that analysis, and a review of critical management

issues for the Federal Aviation Administration (FAA) has been added to the basic questions about the adequacy of Federal standards and programs. During the course of the study,

it became clear that a full report for Congress would have to consider how policy is determined and implemented, and thus the operation of FAA and the role of the Department

of Transportation. This comprehensive look at aviation safety also includes the economic

framework of the industry as it affects operations, an analysis of safety data, and a review

of research and development for safety technologies for both industry and government.

Throughout the study, the advisory panel, review group, workshop participants, and

a host of contributors (see app. B) played key roles in developing the major issues and contributed a broad and invaluable range of perspectives. OTA thanks them for their substantial commitment of time and energy. Their participation does not necessarily represent endorsement of the contents of the report, for which OTA bears sole responsibility.

Director

,..

Ill
Safe Skies for Tomorrow:

Aviation Safety in a Competitive Environment

Advisory Panel

Charles Curtis, Panel Chairman

Van Ness, Feldman, Sutcliffe, & Curtis

Carla J. Berroyer

Deputy Director for Intergovernmental Affairs

Illinois Department of Transportation

Philip T. Brown

Director, Marketing Resources Division

The Travelers Companies

Joan Claybrook

President

Public Citizen

John C. Dannemiller

President and Chief Operating Officer

Leaseway Transportation Corp.

Robert A. Davis

Chief Project Engineer

747 Division

Boeing Commercial Airplane Co.

R.V. Durham

Director, Safety and Health Department

International Brotherhood of Teamsters

James Johnston

President

Owner-Operators Independent Drivers

Association of America

Clyde Kizer

Vice President, Technical Services

Maintenance and Operations Division

United Airlines

Lillian Liburdi

Director

Management and Budget Department

Port Authority of New York and New Jersey

William A. Maloney

Associate Administrator for Motor Carriers

Rhode Island Public Utilities Commission

Louis M. McNair

Executive Central Air Safety Chairman

Air Line Pilots Association

John Meyer

James W. Harpel Professor

The Kennedy School of Government

Harvard University

Richard C. Schwing

Senior Staff Research Engineer

General Motors Research Laboratories

Dean Stanley

Corporate Vice President for Engineering

Navistar International Corp.

Alan Stephen

President

Scenic Airlines

NOTE: OTA appreciates and is grateful for the valuable assistance and thoughtful critiques provided by the advisory panel members. The panel does not, however, necessarily approve, disapprove, or endorse this report. OTA assumes full responsibility for the report and the accuracy of its contents.

iv
Safe Skies for Tomorrow

Aviation Safety in a Competitive Environment

OTA Project Staff

John Andelin, Assistant Director, OTA

Science, Information, and Natural Resources Division

Nancy Carson

Science, Education, and Transportation Program Manager

Edith B. Page, Project Director

Kevin Dopart, Analyst

Leonard Wojcik, Analyst

Karen Mathiasen, Research Assistant

Marsha Fenn, Administrative Assistant

Christopher Clary, Administrative Secretary

Madeline Gross, Secretary

Leslie Ridenour, Administrative Secretary

Michelle Haahr, Secretary

Congressional Research Service

John W. Fischer, Economics Division

J. Glen Moore, Science Policy Research Division

Contractors

Julia Connally

Thomas D. Hopkins

Francine Rudoff

Simat, Helliesen & Eichner, Inc.
CHAPTER

CONTENTS

Page

I: SUMMARY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Evaluating Safety in Times of Change . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Safety Management . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

System Operating Improvements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Changes in the Safety System: Industry . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Changes in the Safety System: FAA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

FAA Planning and Air Traffic System Management . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Personnel and Training . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Technologies To Enhance Safety . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

R&D Management . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

FAA Safety Data Programs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

CHAPTER 2: AIRLINE ECONOMIC CONTEXT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Commercial Air Transportation–Major Changes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Growth in the Industry . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Consolidations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Aircraft Acquisition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Regional Airlines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Shift Away From Open Entry . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

International Ties. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Operational Changes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Hub and Spoke Service . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Code-sharing. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Computerized Reservation Systems (CRS). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Controlling Costs. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ... ..

Profit and Debt Trends . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Policy Issues Related to Industry Changes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Airport Capacity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Demand Management.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Effects of Consolidations on Employees . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Federal Labor Policy Changes . . . . . . . . . . 1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Public Policies Affecting Airline Operations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Air Traffic Controller Strike in 1981 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Federal Budget Cutbacks and FAA Inspection Program . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Environmental Concerns . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ........ .. .. . . . . . . . . . . . . . . . . . . . .

CHAPTER 3: REGULATORY AND INSTITUTIONAL FRAMEWORK . . . . . . . . . . . . . . . .

How It All Began . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Air Mail Service . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Early Safety Initiatives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

The Beginning of Economic Regulation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

An Expanding Federal Role . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Industry Expansion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Responding to Industry Growth . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Airline Deregulation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Federal Aviation Safety Structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

FAA Responsibility . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Other Federal Safety Roles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

FAA Funding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Organizational Issues—System Safety Management . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

FAA Regulatory Program . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

The Office of Airworthiness. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Office of Flight Standards . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Regulatory Program Issues . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

3

4

5

7

12

15

16

17

18

20

20

25

25

26

27

29

29

31

32

32

33

33

33

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35

36

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38

39

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40

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41

41

45

45

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52

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58

vi
Adequacy of FAA Minimum Standards . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

The FAA Rulemaking Process . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Air Traffic Control Issues . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

FAA Technology Development Issues . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Manpower and Training Needs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Airport Issues and Safety . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Local Control of Airports . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Airport Noise . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Land Use Policies and Airport Capacity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Conclusions and Policy Options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

CHAPTER 4: SAFETY MEASUREMENTS AND DATA RESOURCES . . . . . . . . . . . . . . . .

Measuring Transportation Safety . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Safety Factors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Exposure Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Nonaccident Safety Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Primary Safety Factors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Secondar y and Tertiary Safety Factors: Industry Safety Posture . . . . . . . . . . . . . . . . . . . . . . . .

Data Resources . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Federal Safety Data Resources . . . . . . . . . . . . . . . . . . . . . . .

FAA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

National Transportation Safety Board . . . . . . . . . . . . . . . .

NASA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

RSPA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Conclusions and Options . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

CHAPTER 5: AVIATION SAFETY DATA ANALYSIS

Accident Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Accidents and Fatalities . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Accident Causes and Types . . . . . . . . . . . . . . . . . . . . . . . . .

Nonaccident Safety Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Incident Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Air Traffic Incidents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

General Incidents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

59

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61

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69

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86

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98

98

99

Accident/Incident Causal Factors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ...................103

Aircraft Capabilities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ............................103

Personnel Capabilities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .......................105

Traffic Environment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..................105

Management Practices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ........................105

Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. ....106

Operations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 108

Regional/Commuter Airline Operations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .............109

Employee Selection and Training . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .......110

Management Policies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..111

Conclusions and Policy Options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..............112

CHAPTER 6: HUMAN FACTORS UNCOMMERCIAL AVIATION . . . . . . . . . ..........117

Human Error . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .............................118

Preventing Errors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ........................119

Compensating for Errors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..........................120

Human Factors Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..........120

Industry and Federal Roles in Human Factors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..121

Growing Concerns . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ...........121

Federal Responsibilities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .........................127

lndustry Responsibilities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ...................,..129

Labor’s Role . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .131

Conclusions and Policy Options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..........131
CHAPTER 7: AIR TRAFFIC SYSTEM TECHNOLOGIES

Elements of the Air Traffic System . . . . . . . . . . . . . . . . . . . . . .

Models for Evaluating Changes to the Air Traffic System.

Airports . . . . . . . . . . . . . . . . . . . . . . .

Airspace . . . . . . . . . . . . . . . . . . . . . . .

The National Airspace System Plan.

Air Traffic Control Hardware and

TRACON Improvements . . . . . . . .

Training Air Traffic Controllers . . . .

Collision Avoidance Technology . . .

Ground Collision Avoidance . . . . .

Communications . . . . . . . . . . . . . . . . .

Navigation . . . . . . . . . . . . . . . . . . . . .

Surveillance . . . . . . . . . . . . . . . . . . . .

Weather Technologies and Training

Windshear . . . . . . . . . . . . . . . . . . . . .

National Weather Service . . . . . . . .

Air Traffic Control Role . . . . . . . .

Software . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . .

,..,. . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . .

Weather Research and Development . . . . . . . . . . . . . . . . . . .

Liability Issues . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Conclusions and Policy Options . . . . . . . . . . . . . . . . . . . . . . . . .

CHAPTER 8: AIRCRAFT TECHNOLOGIES . . . . . . . . . . . .

Regulation of Aircraft Technologies. . . . . . . . . . . . . . . . . . . . . .

Airworthiness . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Equipment Certification Process . . . . . . . . . . . . . . . . . . . . . . .

Simulators for Pilot and Mechanic Training. . . . . . . . . . . . .

The Future of Commercial Aircraft Technology . . . . . . . . . . .

Cockpit Technologies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Advanced Materials for Aircraft . . . . . . . . . . . . . . . . . . . . . . .

New Aircraft Engine Types . . . . . . . . . . . . . . . . . . . . . . . . . . .

Technologies and Training for Icing. . . . . . . . . . . . . . . . . . . .

Crash and Fire Safety Technologies . . . . . . . . . . . . . . . . . . . .

Conclusions and Policy Options.. . . . . . . . . . . . . . . . . . . . . . . .

APPENDIX A: LIST OF ACRONYMS . . . . . . . . . . . . . . . . . .

Page

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. . . . . . . . . . . . . . . . . . . . . . . . . . . . 175

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. . . . . . . . . . . . . . . . . . . . . . . . . . . . 179

APPENDIX B: WORKSHOP PARTICPANTS, REVIEWERS, AND CONTRIBUTORS. ..180

Boxes

Box Page

l-A. Commercial Aviation Safety Policy Options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

2-A. Airport Scheduling Meetings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37

3-A. A Regulatory Enigma: When is a Commuter an Air Carrier and

When is it an Air Taxi? . . . . . . . . . . . . . . . . . . . . . . . . . . .

3-B. Overview of the FAA Regulatory Program . . . . . . . . . . .

3-C. A Case Study: 747-400 Passenger Exit Doors . . . . . . . . .

4-A. Measures of Transportation Safety: Definitions . . . . . . .

6-A. Air Traffic Control Automation . . . . . . . . . . . . . . . . . . . .

Figures

Figure

l-1. Passenger Fatality Rates for Part 121 Scheduled Airlines

l-2. Total Operations at Towered Airports . . . . . . . . . . . . . . .

l-3. Air Traffic Activity at Selected Hubs . . . . . . . . . . . . . . . .

l-4. Air Carrier Near-Midair Collisions . . . . . . . . . . . . . . . . . . .

l-5. Accident Cause and Prevention Chain . . . . . . . . . . . . . . .

... . . . . . . . . . . . . . . . . . . . . . . . 50

. . . . . . . . . . . . . . . . . . . . . . . . . . . . 56

. . . . . . . . . . . . . . . . . . . . . . . . . . . . 57

. . . . . . . . . . . . . . . . . . . . . . . . . . . . 73

. . . . . . . . . . . . . . . . . . . . . . . . . . . . 125

Page

. . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

. . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

. . . . . .,... . . . . . . . . . . . . . . . . . 8

. . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

. . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Figure Page

l-6. Part 121 Total and Human Error-Caused Accidents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

l-7. Average Flight Equipment Maintenance Expense for B727-200 Fleet . . . . . . . . . . . . . . . . . . 14

l-8. Basic In-Flight Rate, B727/JT8D Engines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

2-l, Scheduled Airline Passengers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

2-2. Air Traffic Activity at Selected Hubs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

2-3. Large Aircraft in Commercial Service . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

2-4. Industry Market Share: Revenue Passenger-Miles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

2-5. Expense Indicators of Major Airlines, 1978-1986: Labor and Maintenance . . . . . . . . . . . . 34

2-6. Net Profits of Major Airlines, 1986 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36

4-1. Commercial Aviation Accident Causal and Preventive Factors . . . . . . . . . . . . . . . . . . . . . . 72

5-1. Passenger Fatality Rates for Part 121 Scheduled Airlines . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93

5-2. Airline Accidents Initiated by Aircraft Equipment Failure . . . . . . . . . . . . . . . . . . . . . . . . . . 96

5-3. Part 121 Accident Broad Causes and Factors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96

5-4. Air Carrier Near Midair Collisions ( 1975-87). . . . . . . . . . . . . . . . . . . . . . . . . . ............100

5-5, operations Per Controller at Towers and Centers . . . . . . . . . . . . . . . . . . . . . ............102

5--6. Basic In-flight Shutdown Rate, B727/JT8D Engines . ...............................104

5-7. Average Flight Equipment Maintenance Expense for B727-200 Fleet . . . . . . . . . . . . .. ....107

6-1. Part 121 Total and Human Error-Caused Accidents . . . . . . . . . . . . . . . . . . . . . . . . . . . . ....117

7-1. Air Traffic Control on a Typical Commercial Flight . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .141

7-2. Locations of Air Route Traffic Control Centers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ...142

7-3. Terminal Areas Where Radar Coverage is Provided . . . . . . . . . . . . . ...................144

7-4. Locations of TRACONS With ARTS-111A and ARTS-IIIE Equipment. . ..............145

7-5. Locations of Airport Surface Detection Equipment Radars . .........................150

7-6. Windshear Accidents and Incidents Before and After LLWAS Implementation . .......158

8-1. Controlled Flight Into Terrain: Descent and Approach Phases of Flight . .............166

Tables

Table Page

l-1. Commercial Aviation Accident and Fatality Rates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

l-2. Part 121 Accident Causes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

1-3. Qualifications of New-Hire Commercial Flight Crews . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

l-4. Selected FAA Employee Totals (1978-87) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

2-1. Commercial Aviation Traffic Statistics, 1986 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

2-2. Regional Airline Revenue Passenger-Miles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

2-3. Percentage of Passengers Enplaned by Airlines at Selected U.S. Airports . . . . . . . . . . . . . . 32

3-l, Selected FAA Employee Totals, 1978-87 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52

4-1. Safety Measures and Exposure Parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71

4-2. Federal Aviation Safety Databases . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78

5-1. Commercial Aviation Accident and Fatality Totals, 1975-1987 . . . . . . . . . . . . . . . . . . . . . . 94

5-2. Commercial Aviation Accident and Fataltity Rates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94

5-3. Accident Categories . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97

5-4. Part 121 Fatal Accidents, 1975-86 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97

5-5. Part 121 Total Accidents, 1982-1985 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98

5-6. Commercial Aircraft Midair Collisions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99

5-7. Qualifications of New-Hire Commercial Flight Crews . . . . . . .........................110

6--l. Significant Jetliner Accident Causes in 93 Major Accidents Worldwide (1977-1984) ....117

7-1. Status of Major National Airspace System (NAS) Plan Projects . . . . . . . . . . . . . . . . . . . . . .140

ix
Chapter 1

Summary

Photo credit: The Singer Co.

Advanced technology cockpits are important to the aviation safety system.
CONTENTS

Evaluating Safety in Times of Change . . . . . . . . . . . . . . . . . . .

Safety Management . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

System Operating Improvements . . . . . . . . . . . . . . . . . . . . . . . .

Changes in the Safety System: Industry . . . . . . . . . . . . . . . . . .

Changes in the Safety System: FAA. . . . . . . . . . . . . . . . . . . . .

FAA Planning and Air Traffic System Management . . . . .

Personnel and Training . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Technologies To Enhance Safety... . . . . . . . . . . . . . . . . . . . . .

R&D Management . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

FAA Safety Data Programs . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Box

1-A. Commercial

1-1.

1-2.

1-3.

1-4.

1-5.

1-6.

1-7.

1-8.

Table

Box

Safety Policy Options. . . . . . . . . .

Passenger Fatality Rates for Part 121 Scheduled Airlines

Total Operations at Towered Airports . . . . . . . . . . . . . . .

Air Traffic Activity at Selected Hubs . . . . . . . . . . . . . . . .

Air Carrier Near-Midair Collisions . . . . . . . . . . . . . . . . . .

Accident Cause and Prevention Chain . . . . . . . . . . . . . . .

Part 121 Total

Average Flight

Basic In-Flight

. . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . .

4

5

7

12

15

16

17

18

20

20

Page

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. . . . . . . . . . . . . . . . . . . . . 3

. . . . . . . . . . . . . . . . . . . . . 7

. . . . . . . . . . . . . . . . . . . . . 8

. . . . . . . . . . . . . . . . . . . . . 9

. . . . . . . . . . . . . . . . . . . . . 11

and Human Error-Caused Accidents . . . ,....,. . . . . . . . . . . . . . . 12

Equipment Maintenance Expense for B727-200 Fleet . . . . . . . . . . 14

B’727/JT8D Engines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

Tables

Page

l-1. Commercial Aviation Accident and Fatality Rates . . . . . . . . . . . . . . . . . . . . . . . . . .

l-2. Part 121 Accident Causes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

l-3. Qualifications of New-Hire Commercial Flight Crews . . . . . . . . . . . . . . . . . . . . . . .

l-4. Selected FAA Employee Totals (1978-87) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

5

10

14

17
Chapter 1

Summary

Americans are a people both fascinated and frightened by flying. Thousands of U.S. citizens travel

safely by air daily; air travelers numbered some 480

million in 1987, and lured by lower fares, passenger ranks have swelled by some 10 percent annually over the past 3 years. Yet no story about air

travel seems too unimportant for media attention.

Almost daily, newspaper stories chronicle the latest

near midair collision (NMAC) or on-time and passenger complaint records. How well founded is the

fear and how much of it is an outgrowth of the awe

with which humans naturally view the marvel that

flight represents?

Thanks to sustained and collective effort, the

United States has achieved an aviation safety record that has continued to improve over time (see

figure 1-1) and now ranks among the best in the

world. Indeed, major passenger aircraft crashes are

so infrequent that identifying aspects of the safety

system that need modification requires thorough

and wide-ranging research.

Figure 1-1.— Passenger Fatality Rates for

Part 121 Scheduled Airlinesa

1935 40 45 50 55 60 65 70 75 60 65

Year

apafi 121 scheduled airlines transport over 90 percent of commercial avlatlon

passengers.

SOURCE: Office of Technology Assessment based on data compiled from the

Civil Aeronautics Board, Federal Aviation Administration, and National Transportation Safety Board

Countless, interrelated, and overlapping supports

form the safety system for commercial aviation in

the United States. Participants include the Federal

Aviation Administration (FAA); the U.S. Department of Transportation (DOT); the airlines and related labor groups; the aircraft and equipment manufacturers; and the public’s elected representatives—

the U.S. Congress. Numerous other groups, including the National Transportation Safety Board

(NTSB), the National Aeronautics and Space Administration (NASA), the National Weather Service, and a variety of consumer and industry safety

advocates, also play important roles. Together, these

groups form an aviation safety system that is exceedingly complex and effective-only a few hundred of

the 2 million deaths in the United States annually

are from commercial aviation accidents, a marked

contrast to the tens of thousands of annual motor

vehicle accident fatalities.

Pivotal members of this safety network, the airlines, each follow individual corporate philosophies,

but have one common characteristic–during the

past decade each has changed operating practices

to control costs, eliminating some of the layers of

the old safety system and replacing them with alternatives that must still be evaluated. While “safety

comes first” is the instant response of airline executives when asked the basis for management decisions, this universal answer masks wide variances

in airline corporate cultures and operating procedures.

Safety first means one set of corporate guidelines

to the airline that already owns adequate landing

slots at a crowded airport and has ample financial

reserves to purchase additional slots. It means something else entirely to a financially strapped airline

that must choose between discretionary maintenance of its aircraft and purchase of additional airport slots, because it cannot afford both. These alternatives illustrate that each airline uses different

parameters to make the choices necessary to satisfy

customers with reliable, low-fare service and still

make a profit in a fiercely competitive industry.1

ll~fOr~~tiO~ In this report on changes in the industry IS drawn directly from OTA’S primary research, including workshops, site visits,

and conversations and correspondence with representatives of industry and the research community.

3
4

Media and congressional examination of passenger delays, on-time departures, and airline labor and

maintenance practices are symptoms of the profound and rapid changes industry has undergone.

Similar scrutiny of air traffic controller and inspector work force levels, tensions between DOT and

FAA, and progress of the National Airspace

System

2 AS) Plan are byproducts of national

2The National Airspace System Plan is a loose grouping of long-term

technology improvements for the Federal Government’s operati~ns of

the airways and air traffic control. Components include (among others)

the Advanced Automation System for air traffic, Doppler weather radar, and the Microwave Landing System.

budget constraints, which have left FAA scrambling

vainly to catch up with industry. Even after trouble spots have been pinpointed, Federal processes

to put in place regulations, technologies, or programs

as countermeasures are excessively time-consuming.

Major changes in regulations, such as requirements

for ground proximity warning systems or collision

avoidance devices, usually occur only in the shocked

and saddened aftermath of a major airline accident,

even though the underlying causal problems were

recognized years earlier.

EVALUATING SAFETY IN TIMES OF CHANGE

Before passage of the Airline Deregulation Act

(ADA) in 1978, the commercial airline industry was

relatively stable. Industry changes occurred slowly,

a constant group of carriers competed for the travel

dollar, and the costs of required safety improvements

could be passed quickly to the consumer. ADA removed Federal controls over routes, fares, and new

entries to encourage competition, but left unaltered

FAA’s responsibility for commercial aviation safety.

Events of the past decade have shown that neither

Congress nor the executive branch fully comprehended the complexity of overseeing and regulating a newly competitive industry.

To determine how changes in airline operations

after deregulation affected air safety and what steps

the Federal Government could take to ensure safe

skies for tomorrow, OTA took a comprehensive

look at the entire commercial air safety system. The

first step included a review of FAA safety operations

and program areas, including technology development and training. This was followed by review and

analysis of safety-related data from all available government and industry sources. The final component

was identifying and assessing the changes in industry practices that have occurred over the past decade in the wake of economic deregulation. Financial data from the large and small airlines and

information from the industry, collected on a confidential basis by OTA, were the major resources

tapped.

Aggregate accident data show that the number

of accidents for large airlines has held steady and

has declined slightly for small airlines in the decade since deregulation (see table 1-1). However,

growth in commercial air travel and the dominance

of hub and spoke operations have changed airline

and air traffic operations, in some cases dramatically.

Vigorous Federal safety management programs and

technical and operational oversight are vital to ensuring a high level of public safety, especially in a

period of major upheaval. FAA, hard hit by budget cuts and personnel reductions, has fallen behind

in both numbers of staff and levels of technical expertise.

OTA identified two key areas for enhancing air

safety:

●

●

safety management improvements, including

streamlining FAA’s internal organization, increasing inspector and operating work forces,

raising levels of expertise, and establishing

the primacy of FAA’s safety responsibilities

to ensure a more powerful system safety program; and

system operating improvements, including

expanding air traffic control (ATC) capacity

and capability; enhancing human performance; and upgrading weather forecasting, detection, and dissemination and air/ground

communications.
5

Table 1-1 .—Commercial Aviation Accident and Fatality Rates

Part 121 Part 121 Part 135a Part 135b

Year (scheduled) (nonscheduled) (scheduled) (nonscheduled)

Accidents per million departures:

75-77 . . . . . . . . . . . . . . 4.8 53 27 58

78-80 . . . . . . . . . . . . . . 3.7 39 27 54

81-83 . . . . . . . . . . . . . . 4.1 18 12 55

84-86 . . . . . . . . . . . . . . 2.8 22 8 53

87 . . . . . . . . . . . . . . . . 4.3 23 14 38

75-87 . . . . . . . . . . . . 3.8 30 17 54

Fatal accidents per million departures:

75-77 . . . . . . . . . . . . . . 0.48 10.6 6.3 11

78-80 . . . . . . . . . . . . . . 0.57 6.5 6.5 13

81-83 . . . . . . . . . . . . . . 0.72 2.6 2.6 13

84-86 . . . . . . . . . . . . . . 0.34 8.0 2.1 11

87 . . . . . . . . . . . . . . . . 0.43 4.6 4.1 12

75-87 . . . . . . . . . . . . 0.51 6.5 4.1 12

Fatalities per million passengers-enplaned:c

75-77 . . . . . . . . . . . . . . 0.34 24.2 3.4 14

78-80 . . . . . . . . . . . . . . 0.56 0.2 4.4 13

81-83 . . . . . . . . . . . . . . 0.26 0.1 1.5 11

84-86 . . . . . . . . . . . . . . 0.17 14.7 1.6 9

87 . . . . . . . . . . . . . . . . 0.41 0.1 2.8 10

75-87 . . . . . . . . . . . . 0.33 9.1 2.6 12

as~h@jul~d pan IX Pass enger counts estimated by OTA based on Regional Airline Association data,

bNonscheduled pa~l~ passenger anddeparturedata estimated byOTA based on National AirTransportation Association

and other air taxi data.

cOTA calculations based on National Trarlsportatbn Safety Board and Federal Aviation Administration data. All 1W7 rates

based unestimated passenger-enplanement data.

SOURCE: Office of Technology Assessment based on National Transportation Safety Board data as of JanuaV 198S, unless

otherwise noted.

SAFETY MANAGEMENT

FAA has a dual mandate: “. . . to promote safety

of flight . . . in air commerce through standard setting . . .“ and to carry out for the Secretary of Transportation the responsibility “. . . to encourage and

foster the development of air commerce.”3 While

these tasks are not necessarily incompatible, an inherent tension exists between them in two vital

safety activities of FAA—inspections, and managing and operating ATC. In times of massive change

and rapid travel growth, such as the past decade,

fulfilling both goals of the mandate presents the

agency with unavoidable conflicts. The pressures on

the air traffic system of airline schedules bunched

at peak hours provide one obvious example. OTA

concludes that if Congress wishes safety to be preeminent in FAA’s mandate, it may wish to make

that explicit.

OTA analysis indicates that many FAA safety

functions need strengthening. Among the most im-

‘Public Law 85-726.

Photo credit: Federal Aviation Administration

Heavy traffic places extra demands on air traffic control

and the aviation safety system.

portant are raising inspection and air traffic personnel levels; near-term improvements to ATC to cope

with increased traffic; analytic tools for managing

airport and airspace demand; training programs for

inspectors, controllers, and technicians; programs
6

and systems for tracking and analyzing safety data;

and long-range system planning.

Furthermore, FAA could recognize system safety

management as a specific goal and refocus existing

programs accordingly. For example, new emphasis

could be placed on systematic and regular monitoring of financial conditions and management changes

at airlines, realistic life-cycle planning for costs and

personnel for the NAS Plan, and vigorous programs

in hazard and human factors analysis for new technologies. OTA concludes that additional, stable

funding resources to support these functions and

FAA policy and resource management, technical

competence, and system safety oversight will be

needed. A rough analysis of programs and funding needs may be found in box l-A.

Improvements will not be sufficient if made piecemeal, however, because the safety functions of FAA

are so closely interrelated. OTA concludes that

FAA’s functions cannot be separated into regulatory and operating (ATC) components without

diminishing the effectiveness of the entire system.

Furthermore, without more emphasis on system

safety at the very top, FAA agency-wide problems

that have hampered the organization’s capabilities

are likely to continue. Moreover, FAA organizational problems have exacerbated the impacts on

the agency of government-wide problems of inefficient Federal personnel and procurement requirements and national budget constraints and priorities.

Management changes are needed that increase

and support long-range planning; technical capabilities; internal coordination, especially between

research and development (R&D) activities and

ongoing operations; even-handed application of regulations in inspections, enforcement, and certification across regions; and management information

systems. Shortcomings in these activities are embedded in the FAA structure and operations and

Box 1-A.-Commercial Aviation Safety Policy Options

Maintain current Approximate costs

safety with Increase ($ millions) *

Policy option ‘, ,:: increased demand safety Fixed Recurring

FAA management improvements:

1. Make safety FAA's preeminent responsibility. . . X X <1

2. Lengthen term term of Administrator. . x X <1

3. Sttwdtw FAA wgm&atiori ● .***.** 6*. 4$. ,, x I

4. Increase hapt@@r !@@lg . ● . s * ● * . . ● “ * ● . ● . * . ● . x x <1

5. Address -neltames ofniiocat@n, ~nkai

expmtiw, and comperw@Q~ + *4+*,..”*.**,,,*

4. pragmms &Yr field and fidty

● * . ● ● ● 4 , *’ ● * . * ● . * ● * * . , . ● . . , + .- ● * * . ● ,

7. Improva data dletion mid W+X . *..*,*..*

Syatain ‘

1. Nw+ ...,....,,..,...

2* ctmtrdlef @ WCMMitn i * ● ● h * .< * * ● ● * , x <1

3* me a&p#t de+t!ik$p

system capadty rndd& . . . . . . . . . . . . ... .....: . . x 20

4. Undertake human fiwtors reswwch and I

incorporate inm proewlurwJ atid rcgukions.. . . x x 20

5, Enhance hazardous weather safety and

<1

<1

1

60

40

20

5

2

300

2

5

communications ● ● ● ● ● ● . , ● . . , ● ● ● + ● . . . . . . . . ● ● . ● x x 00 ~D•Œ <1

SOURCE: OSke (#Technology &atsmmt, MIS.
7

affect air traffic operations, technology development, sources from the General Fund and the Air.

and safety standards programs alike. port and Airway Trust Fund;

The most striking improvement in FAA operations and regulatory and oversight programs would

result from the establishment of strong, independent, and consistent leadership by the FAA Administrator. Congress may wish to consider three farreaching changes to bring about this goal:

• streamlining the structure of FAA to give the

Administrator direct control of the far-flung

organization and to permit holding subordinates accountable for system safety; and

• increasing the Administrator’s length of tenure to a fixed term, perhaps up to 5 years. To

provide accountability, Congress may wish

establishing the preeminence of the safety to require the Administrator to develop a

function in FAA’s mandate, holding the Ad- rolling 5-year agency development plan and

ministrator accountable solely for safety, and report annually on its status.

allocating stable and adequate funding reSYSTEM OPERATING IMPROVEMENTS

Commercial air transportation operations (takeoffs and landings) at U.S. airports with FAA control towers have reached record levels each year since

1984, with commuters and air taxis accounting for

one-third of those flights.4 Due to declines in general aviation (GA) activity across the country, total traffic nationwide is still below the peak of 69

million operations reached in 1979 (see figure 1-2).

Although GA and military flights generate a large

volume of traffic nationwide, they represent only

a fraction of the operations at the largest and busiest airports—less than 6 percent at Chicago O’Hare

and Atlanta Hartsfield, for example. While GA (and

some military aircraft) share the facilities, air carrier operations account for most increases in operations at major airports (see figure 1-3).

The good news is that more people can afford to

fly. But increased traffic does strain industry, airport, and ATC equipment and personnel, requiring them to perform consistently at peak ability—a

requirement they are often ill-equipped to meet.

Strains are visible in the form of travel delays at

some airports even in good weather, due to air traffic

and airport congestion-, equipment malfunction, and

occasionally aircraft and ground crew shortages.

Plans to build more runways and modernize airports

have been stymied by interjurisdictional disputes

‘Air traffic controllers, t~ho record data on traffic operations, do not

differentiate commuters from air tax]s or Part 121 commuters from Part

135 commuters. Acidltlonally, since many alr taxis are similar to general a~’latlon aircraft, an air taxi operation probahlv will not be counted

as such unless it I< so Indicated in the fllght plan. Therefore, alr taxi

operations are most Ilkelv underestimated by these statistics.

10

0

I

1975 76 77 7879 80 81 82 83 84 85 86 87

Year

m Air carrrier El Air taxi D Military/general aviation

SOURCE: Office of Technology Assessment based on Federal Aviation Administration data.

over noise and land use that are unlikely to be resolved in the near term. ATC system renewal has

moved at glacial speed, slowed by inadequate system planning, technology development difficulties,

and administration and congressional budget de--

cisions.

OTA found that increases in commercial air traffic

correspond closely to the rise in reported NMACs
8

Figure 1-3.—Air Traffic Activity at Selected Hubs

Phoenix sky Harbor

1

‘1975 767778796081 82636466668 7

Year

100

0

197576 77 7879600162636466668 7

Year

100

0

1975767778796081 62636465668 7

Year

100

0

19757677787960818203 6465668 7

Year

- Air carrier ~ Air taxi ~ Mititary/general aviation

SOURCE: Office of Technology Assessment based on Federal Avlatlon Administration data.
9

Photo credit: Federal Aviation Administration

While they share the airspace with commercial airlines,

general aviation planes make up only a fraction of the

flights at the Nation’s busiest airports.

involving commercial aircraft (see figure 1-4). While

air traffic-related accidents are quite rare, and midair

collisions show no trends, rising NMAC reports suggest that future growth in commercial traffic is a

cause for concern. OTA concludes that continued

vigorous air traffic growth and increased traffic

densities at more airports could outstrip the capabilities of the traffic system. Without immediate steps to modernize the ATC system and to

manage air traffic flow and demand as necessary,

present safety levels may not be sustainable.

However, decisions about managing demand have

major economic consequences for airlines—spelling

success or failure for some small commuter airlines

or large airlines in precarious financial condition.

Such decisions thus pose serious equity issues and

require careful scrutiny, public debate, and cooperative, deliberate decisionmaking backed by sound

technical analysis.

Accidents usually result from a combination of

failures occurring sequentially, or on occasion, simultaneously in one or more activities (see figure 1-5).

Commercial flight safety requires that many varied

activities be carried out without major error. Human error, severe weather, aircraft component failure, and limitations of the air traffic environment

are the four primary causal factors in aviation accidents (see table 1-2).

OTA analyses of data from FAA, NTSB, airlines,

and aircraft manufacturers confirmed that human

Figure 104.—Air Carrier Near Midair

Collisions (1975.87)

Quadradic regression: R-. 94 +

/

+

+

+

+

+

t

I I I I I I I [ I

13 15 17 19 21

Air carrier operations at Federal Aviation

Administration towers (millions)

SOURCE: Office of Technology Assessment based on Federal Aviation Adminis.

tration data.

error is at least partially responsible for over 65 percent of accidents, a percentage that has held constant over the past decade (see figure 1-6). Moreover, aircraft component failures, factors in over 40

percent of all accidents, are often compounded by

human error, and weather-related accidents often

involve faulty decisionmaking or communication.

OTA concludes that long-term improvements in

aviation safety will come primarily from humanfactors solutions, and that such solutions will be

found through consistent, long-term support for

R&D, analysis, and applications. Moreover, current FAA programs to understand human error

and enhance controller, mechanic, and cockpit

crew performance are inadequate. Data on reliability of human performance are difficult to collect,

however, and causes of human error are not fully

understood. The traffic environment, aircraft design,

and management practices directly influence human

performance, and recent changes in aircraft technology and operating practices have widespread implications that require extensive research. Humanfactors hazard analyses, such as studies to determine

whether people can operate new technologies quick-
10

Table 1-2.—Part 121 Accident Causes

Fatal Fatal Total Total

accidents accidents accidents accidents

(1975-86) (by percenta) (1982-85) (by percenta

)

Initiating causal factor:

Pilot . . . . . . . . . . . . . . 15 43 23 46

Personnel . . . . . . . . . . 5

b

14 4

C

8

Aircraft . . . . . . . . . . . . 9 26 18 36

Weather . . . . . . . . . . . 3 9 2 4

Miscellaneous . . . . . . 3d 9 3

e

6

All causal factors:f

Pilot . . . . . . . . . . . . . . 20 57 27 54

Personnel . . . . . . . . . . 5 14 4 8

Aircraft . . . . . . . . . . . . 12 34 23 46

Weather . . . . . . . . . . . 9 26 11 22

Miscellaneous . . . . . . 3 9 3 6

Total accidents . . . 35 50

NOTE: Accidents involving weather turbulence, sabotage, or nonoperational events, such as ramp activities, are not included.

alnitiating causal factors may not total IM percent due to rounding, For all causal factors, numbers do not total 100 percent,

because most accidents involve multiple causes.

bThree a~~idents involving air traffic control personnel, one involving t77dfltWUWICeP3rSOnnd, and one involvin9 the Pilot of

another aircraft.

CTWO accidents involving air traffic control personnel and two irlVOIViflg fllalflteflaflce peLSOflfld.

dTwo midair colli5ion5, including A“rOrn”xlCO DC.9/PA 2&181 over C“rritos, CA on Aug. 31, 1986, and one in-flight COlliSiOfl

with a parachutist.

eTwo collisions with birds and one collision while t5xiin9.

f All cau5al factors includes up t. two significant causes in the sequence of events leading to the accident.

SOURCE: Office of Technology Assessment based on National Transportation Safety Board data as of January 1988.

ly and accurately in an emergency, are not presently

a normal part of aircraft or ATC system design or

certification. Such studies are vitally important as

future technologies are introduced. Automation, pilot and controller selection and training, and the

effects of management practices are specifically in

need of attention.

In the short term, existing resources and understanding of human factors at NASA, the Department of Defense, universities, and industry could

be utilized. FAA could request assistance from these

groups to provide guidance for developing and disseminating explicit training procedures for upgrading crew coordination and decisionmaking. In the

longer term, Congress may wish to consider making human factors a core research technology and

direct FAA to designate management resources

for a research program. An FAA program that utilizes available human-factors expertise at NASA

and other organizations to carry out fundamental work in this area could bring improvements

to safety without large expenditures of additional

funds.

While technological progress has contributed

greatly to advances in air safety, further improvements through technology will come at relatively

higher cost. Nonetheless, OTA concludes that

technologies to improve prediction, detection,

and interpretation of severe weather and for communicating and coordinating this information between ATC and the cockpit could contribute substantially to greater safety. In particular, FAA

commitment to rapid integration of modern, digital air/ground communications, augmented by

appropriate automation, could increase both safety

and efficiency.
11

I

\ \

/

/

\

i

/

1

/

/\
12

Figure 1-6.– Part 121 Total and Human Error.

Caused Accidents

6 ,

5

1

0

75-77 78-80 81-83 84-85

Years

= All accidents ~ All human errors ~ pilot errors

SOURCE: Office of Technology Assessment based on National Transpotiation

Safety Board data, 1975-85. Data from 1986 and 19S7 are not yet

available.

CHANGES IN THE SAFETY SYSTEM: INDUSTRY

Commercial aviation includes flights by scheduled

large jetliners, smaller commuter planes, and air

taxis, as well as cargo and charter jet service. Each

industry segment has substantially different safety

and economic effects on the aviation system. For

convenience, OTA will refer to airlines as major

(large) or commuter (regional). In practice, however,

the divisions under the regulations are far from being so simple (for details see box 3-A in ch. 3). The

formal designations for these airlines are:

● Major or large—14 CFR Part 12 l—operations

of aircraft with more than 30 seats or 7,500

payload-pounds. Part 121 airlines carried 95 percent of passengers and accounted for 99 percent of revenue passenger-miles in 1986.

● . Commuter—14 CFR Part 135—operations of

aircraft with 30 seats or fewer. Part 135

commuter 5 airlines transported 4 percent of

5These definitions can be confusing; some portions of the Federal

Code apply the terms “commuter” or “regional” to scheduled operations of aircraft with 60 seats or fewer. Accident statistics show that

the largest commuter airlines are as safe as the major carriers.

Photo credit: Fokker Aircraft USA, Inc.

Some commuter airlines, such as this one, adhere to

the same operating and airworthiness standards

as large jetliners.

passengers, and air taxis accounted for only 1

percent.

The single most significant change in large airline

operations over the past decade has been the almost

universal shift to hub-and-spoke operations that enable airlines to dominate their most successful markets. To retain connecting passengers, the major air-
13

lines have made arrangements with regional and

commuter lines that feed passengers from small communities to their hubs to share identification codes

on computerized reservations systems—a practice

known as code--sharing. Where the performance of

the commuter line is less than satisfactory, or where

a chance exists that a head-to-head competitor at

the hub may make a more favorable code-sharing

arrangement, the major line is likely to buy the commuter outright. Of the 50 largest regional airlines

that existed as independent entities several years ago,

only 2 now remain unattached to a larger airline.

Through hub dominance, the power of computerized reservation system booking, and code-sharing

arrangements, the airline industry in 1988 is virtually

closed to new entrants, except for carriers specializing in specific market niches.

However, competition for passengers remains

keen and economic pressures on carriers are intense. OTA research indicates that while airline

officials are concerned about safety, financial considerations drive many industry decisions and will

continue to do so as long as strong competition

exists among the airlines. Primary decisionmakers

at today’s airlines do not always have the same understanding of operations that permeates management decisions made by experienced officials dedicated to safety.

Many factors related to enlarging market share

and hub scheduling have affected industry’s struggle to modernize and restructure. OTA identified

the following as particularly difficult problem areas.

● Lag time between airlines’ restructuring to capture market share and commensurate changes

in their safety procedures. Hub-and-spoke operations require tight turnaround schedules, leaving little time for minor maintenance tasks during the day. Such operations also require

airlines either to arrange for adequate maintenance capability at the spoke ends of their operations or to fly the aircraft back to a maintenance facility at night for repair. Some airlines

contract with other carriers that have crews and

parts available at spoke points; some redeploy

their own personnel. If flying an ailing aircraft

back to a hub is not feasible, other carriers charter aircraft and fly parts and mechanics to remote sites when necessary.

Photo credit: United Airlines

Careful attention to detail by airline maintenance

personnel and Federal inspectors is essential to

ensure system safety.

●

●

●

As airlines merge or expand rapidly, they acquire or purchase used equipment, often aircraft

different from those in their existing fleet. Some

airlines choose to contract maintenance for

planes that differ from the majority in their

fleets. For other companies, repositioning and

retraining maintenance personnel and rearranging equipment and inventory takes time and

planning. Few airlines understood ahead of time

how much care and advance planning would

be required for these changes in their ground

operations.

Every airline has made differing and substantial structural changes to improve economic efficiency, although each company vigorously denies compromising safety by the alterations it

has made. To lower costs some airlines have reduced planning and engineering departments,

while others have pared back safety departments. Others eliminated weather or meteorology sections or began to make discretionary

maintenance spending decisions based on the

tightness of the budget. So long as airlines comply with minimum Federal standards, FAA has

no grounds for questioning these types of decisions.

Mergers have caused substantial industry readjustments; in some cases, flight crews have had

to learn entirely new procedures. FAA does not
14

have human factors expertise to monitor or predict the impact of such changes on pilot performance, and Federal regulations are silent on

methods to assist airline personnel through the

difficulties inherent in a merger. Finally, while

many small commuter airlines remain independent, numerous regional airlines now operate as adjuncts to major carriers. Only a few

of the major airlines have taken steps to bolster the safety of their commuter lines by assisting with pilot and mechanic training.

Many airlines have hired large numbers of flight

and maintenance personnel to meet shortages

caused by retirements and increases in air travel.

While larger airlines have been able to keep experience levels high by hiring recently retired

military pilots or pilots from smaller airlines,

commuter airlines find themselves used as training grounds for larger carriers, which offer

higher salaries and opportunities to fly jet aircraft. Several commuter carriers told OTA that

they are experiencing over 100 percent turnover

annually in their pilot ranks. Training facilities

and programs are stretched, and experience

levels in some of the major airlines and many

of the regional and commuter lines have declined. Many regional airlines must hire pilots

with little or no jet experience and limited flying hours (see table 1-3).

Airline management practices are an important

control valve for commercial aviation safety, and

airlines have always had different approaches to

managing their operations. For example, while some

airlines are reducing or eliminating safety, weather,

or medical departments, other airlines with excellent safety records have never had such departments,

preferring other safety management approaches.

Some airlines are leasing aircraft and contracting

maintenance, finding these procedures to be costeffective. Moreover, OTA analysis showed increased

spending for maintenance (in constant dollars)

across the industry (see figure 1-7) during the past

5 years and no deterioration in aircraft reliability.

(See figure 1-8 for an example.)

OTA finds that many airlines have lowered hire

ing standards, increased pilot and mechanic duty

time, shifted to leased aircraft, and reorganized

and cut wages. However, the cumulative impacts

on safety of these decisions are difficult to quantify. Compensating activities in other parts of the

system may counterbalance safety impacts of these

actions. For example, FAA concentrated its oversight activities in the National Air Transportation

Figure 1.7.—Average Flight Equipment

Maintenance Expense for B727-200 Fleeta

700, i

650 J

550--1

450{ A

350- T

I I I I I I i T I

197677 78 79 80 81 82 83 84 85 86

Year

~ Dollars/revenue aircraft departure

+ Dollars/revenue aircraft hour

aMajor carriers only.

SOURCE: Office of Technology Assessment based on Research and Special Programs Administration data,

Table l-3.—Qualifications of New-Hire Commercial Flight Crews (percent, by year)

Major airlines National airlines Other jet airlines Regional airlines

Pilots with 1983 1986 1983 1986 1983 1986 1983 1986

Less than 2,000 hours total

flight time . . . . . . . . . . . . . . . . . . . . . . . 1 13 0 14 12 9 29

No military experience. . . . . . . . . . . . . . . 46 56 18 66 55 70 83 88

No jet or turboprop flight time. . . . . . . . 1 2 1 6 24 29 32 28

No air transport pilot certificate and

no flight engineer certificate. . . . . . . . 18 26 24 41 42 56 77 76

SOURCE: Office of Technology Assessment based on Future Aviation Professionals of America data, as of May 1987.
15

Figure 1-8.—Basic In-flight Shutdown (IFSD) Rate,

(domestic operators only) B727/JT8D Engines

5

1970 1975 1960 1985

Year

SOURCE: Office of Technology Assessment based on Boeing Commercial Airplane Co. data.

Inspection program in 1984. The inspections showed

that airlines undergoing management turmoil tend

to overlook details of safety programs. Since 1984,

FAA has monitored selected airlines as closely as

possible, given the limited numbers of trained inspectors. Large fines have occasionally resulted from

these FAA activities, and airlines have subsequently

upgraded safety procedures and recordkeeping.6

‘U.S. Department of Transportation, “National Air Transportation

Inspection Program: Federal Aviation Administration, Mar. 4, 1984

- June 5, 1984,” Report for the Secretary, unpublished typescript.

Some airlines have complained that FAA surveillance involves looking at a paper trail only, ignoring the fact that paper records are vital management

tools as well as the major enforcement mechanism

for FAA. Short aircraft turnaround times increase

dependence on records; a 20-minute time period between pull up at the gate and departure leaves insufficient time for a thorough FAA inspection (not

to mention repairs by mechanics). Under such circumstances, the aircraft logbook is an indispensable record of maintenance activities for airline personnel and FAA alike.

Limited Federal resources preclude frequent surprise inspections or indepth, continuous inspections,

except on a special basis. OTA concludes that vigilant FAA oversight of airline management procedures through unannounced inspections and

periodic indepth audits of every large and small

airline are indispensable tools for ensuring public safety. Based on operating and marketing

changes now underway, the commuter industry

warrants extensive and intensive FAA oversight

during the shakeout expected over the next few

years. The special FAA inspection effort for commuters announced in early 1988 is a step in the right

direction. However, it has forced postponement of

several major carrier inspections, because FAA does

not have enough inspectors to do both.

CHANGES IN THE SAFETY SYSTEM: FAA

Since Congress dismantled the Civil Aeronautics

Board, FAA has been the chief regulator of the U.S.

airline industry, with some political and analytic support from other parts of DOT. The task is formidable. On the one hand, the agency must stand up

to intense pressure from DOT and industry on proposed regulatory and programmatic changes, and,

on the other, address constant public and congressional anxieties about safety and convenience. Moreover, local governments play roles in determining

airport operations and development that often conflict with FAA goals. Over the past several years,

public attention has again focused sharply on

whether FAA has the institutional capability and

resources to carry out its operating, standard setting, rulemaking, and technology development functions effectively and guarantee compliance through

its inspection programs.

Over the past decade, FAA’s effectiveness has

been undercut by administration policy decisions

carried out by DOT and by national budget con-
16

straints entirely external to FAA activities. These

have slowed FAA regulatory processes and procurement, limited the size of the inspection, ATC, and

facilities technician work forces, eliminated many

expert technical personnel who chose to seek more

rewarding jobs in industry, and prevented modernization of equipment. Agency training programs,

technical and human factors R&D, and long-range

comprehensive planning have been especially hard

hit.

Only an agency with strong leadership and singleness of purpose and responsibility could maintain

a steady course under such opposing pressures, and

at FAA, such pressures only magnify internal management and structural shortcomings. The agency’s

organization is extraordinarily decentralized, making turf battles inevitable among the 22 top managers reporting to the Administrator. Rapid turnover in Administrators, common in executive

branch agencies, has made such internal disagreements especially destructive. For example, although

policy nominally originates from FAA headquarters, FAA standards for certification are not uniformly interpreted across regions. In at least one

instance—exit doors for the Boeing 747 aircraft—

the responsible region’s ruling was effectively overturned by the Administrator, who wrote to the airlines, asking them not to use the eight-door configuration approved by the region.

OTA finds that while the autonomy of the regions permits allocation of personnel according

to regional need, policy guidance to FAA regions

from headquarters is inadequate to ensure nationally consistent standards. Lack of strong top management, inadequate comprehensive planning, and

diminished technical expertise have led on occasion

to budget and regulatory priorities being set for FAA

through pressure on Congress or DOT policy officials by potent and vocal special interest groups.

Appropriate consideration of system safety is not

always part of this process.

Despite these deficiencies in the organization,

FAA staff members at all levels are dedicated to aviation and to their operational and technical missions.

However, these characteristics do not always lend

themselves to full appreciation for intergovernmental

issues, such as local land use decisions, environmental problems associated with airport construction, or complaints about airline schedule reliability. OTA concludes that many decisions affecting

aviation policy require participation by public

officials at all governmental levels, ranging from

Congress to local airport authorities. Such decisions cannot be made solely by FAA, an organization heavily reliant on technical and industry expertise.

FAA Planning and Air Traffic

System Management

An essential support for system safety management is an agency-wide comprehensive planning capability that includes participation by all major FAA

programs in setting long-term safety goals and budget priorities to achieve them. Coupled with firm,

consistent, top-level guidance, an agency-wide plan

could ease conflicts between and among Associate

Administrators and Regional Office Directors. Lack

of such planning capability has created substantial

difficulties for ATC programs.

In the best of times, airport and ATC issues create tension for FAA between ensuring the maximum

traffic flow desired by industry, meeting safety standards, and considering State or local environmental

and land use concerns. In its 1988 reauthorization

of the Airport and Airway Trust Fund, Congress

reaffirmed the importance of environmental concerns by increasing funding to airport authorities

for land purchases. Such concerns are serious obstacles to near-term airport construction or expansion; we may have to live with existing airports for

some years.

The air traffic system has many individual, interdependent components, and each one affects the

safety and capacity of the overall system. Significant

components affecting capacity of the current air traffic system are:

airports;

air route structure;

the ATC system, including hardware, software

and the humans who operate the system; and

communications.

Any increase or decrease in capacity in one part of

the system (e.g., airports) requires adjustments to

the other parts to stabilize overall system capacity.

FAA badly needs effective tools for evaluating airport and airspace capacity and devising methods for
17

increasing system capacity. At present, for example, weather technologies are used by Central Flow

Control to determine capacity for airports. Aircraft

are held on the ground when the predicted demand

on a destination airport exceeds its capacity, and

system-wide delays often occur as a result.

However, while passengers understand delays due

to bad weather, decisions about capacity in good

weather are much more problematic. Current DOT

methods of encouraging airlines to spread peak hour

demand to avoid delays at busy airports consist basically of jawboning and persuasion. Failure of these

techniques means massive inconvenience and public uproar, Yet devising and implementing equitable

methods of managing demand pose difficult and sensitive policy questions for the government. Air and

ground space management may require imposing

surcharges or altering airline schedules and airport

landing slots at the most congested facilities during

peak hours—actions that directly affect airline profits

and market share. OTA finds that technical expertise from FAA is essential to DOT and Congress

in making difficult decisions on constrained airport and airspace capacity. Continued emphasis

on developing analytic tools, including models, to

help understand the capacity of the air traffic systern would provide FAA with vital technical

knowledge to support difficult future decisions on

capacity, safety, noise, and airline scheduling.

Air traffic equipment improvements, flight path

restructuring, and well-trained operating and support personnel are important near-term safety improvements given existing and projected airport capacity constraints. Both realistic scheduling and a

fully staffed and adequately equipped ATC system

are required for the system to be able to handle safely

continued growth in air travel without burdensome

delays. FAA considers the new Host computers in

en route centers to be adequate until the Advanced

Automation System is available. However, these

computers address only some of the current system

problems. For example, computer and radar capabilities in the Terminal Radar Approach Control

(TRACON) facilities are inadequate to handle the

increased traffic load that will occur when broadened

requirements for altitude encoding transponders in

GA aircraft are implemented. (For further information, see chapter 7.) Currently, the New York

TRACON equipment is being upgraded to handle

increased demand. However, in late March 1988,

FAA announced a request for fiscal year 1989 funds

to upgrade equipment at other TRACONs. OTA

finds that these equipment improvements should

be completed as quickly as possible. They are essential to the successful implementation of broadened transponder and collision avoidance equipment requirements. Congressional support for

funding will allow an important addition to systern safety to go forward.

Personnel and Training

FAA and DOT budget decisions in the early 1980s

to reduce personnel levels created shortages of

trained personnel in three critical areas (see table

1-4), and the safety system continues to feel the effects. For example, the ranks of trained operations

and maintenance inspectors have become very thin,

while airline operations have been changing rapidly

and dramatically. Federal processes are so slow that

FAA became adequately staffed to handle new industry entrants only in 1984, the year that new airlines began to go bankrupt or merge with established

carriers. OTA concludes that FAA inspector, controller, and technician work force levels still do

not meet system safety requirements.

DOT’s budget request for fiscal year 1989 includes

funds for about 2,500 inspectors. However, hiring

Table 1.4.–Selected FAA Employee Totals, 1978-87

Occupation 1978 1979 1980 1981 1982 1983 1984 1985 1986 1987

Air traffic controllera . . . . . . . . 16,750 16,853 16,584 6,658 11,416 11,946 11,944 12,245 12,429 12,847

Aviation safety inspectorb

. . . . 1,466 NIA 1,499 1,615 1,423 1,331 1,394 1,475 1,813 1,939

Electronics technician . . . . . . 9,423 9,209 8,871 8,432 8,031 7,633 7,229 6,856 6,600 6,740

aFull ~erformance level and developmental controllers at towers and centers.

bAir carrier inspectors (approximately AI) percent of the total) were responsible for 145 air carriers, while general aviation inspectors were responsible fOr 173 pall 135

commuter airlines, 7,804 other commercial aircraft operators, and 5,210 aviation schools and repair stations as of Mar. 10, 1988.

communications, navigational aid, radar, and automation technicians.

SOURCE: Office of Technology Assessment based on Federai Aviation Administration data as follows: controller data as of September 1987; inspector data as of March

1988: and technician data as of March 1988.
18

an adequate number of inspectors is just the beginning. As aircraft technologies become more complex and sophisticated, training for aviation inspectors will become even more critical. While efforts

at FAA headquarters to standardize inspection procedures and job descriptions are underway, they will

not be completed for at least another year. FAA

inspectors continue to operate according to the policies and on-the-job training of the particular field

office in which they are located, leading to substantial inequities in enforcement. OTA concludes that

immediate steps to speed standardization of inspection procedures and provide adequate recordkeeping for agency inspection information are priority needs. Project SAFE, FAA’s program to

accomplish these goals, is a move in the right direction, but progress is painfully slow.

Moreover, FAA headquarters, Aviation Standards field offices, and the FAA Academy need a coordinated long-term plan for number of students,

curriculum, and training equipment. Frequently,

Academy courses do not adequately prepare inspectors to take up their duties once they return to the

regional offices. Regional offices, desperate to have

adequately trained personnel to meet the needs of

the airlines they supervise, provide independent

training that varies from region to region, perpetuating the regional differences in application of supposedly national standards. At present, the Academy must react to unforeseeable short-term needs,

rather than proceeding efficiently to improve its

training capabilities.

The firing of striking air traffic controllers in 1981

is an example of a Federal decision made for national

labor policy reasons but felt keenly by FAA. Hiring of new controllers lagged far behind the need,

and a few aftereffects linger to this day. While some

facilities have a plethora of new controllers, they

cannot give them training and experience quickly

and efficiently to relieve the full-performance level

controllers or replace those who retire. Still other

facilities, such as those in the New York City area,

cannot attract new controllers because of the high

cost of living. Federal policies do not permit cost

of living differentials to be paid for employees assigned to high cost areas of the country.

Furthermore, air traffic controller training programs and equipment are outdated and badly in

need of carefully planned and systematic overhaul.

Air traffic controllers at some en route facilities now

receive site-specific training at the FAA Academy in

Oklahoma City because of inadequate resources at the

en route facilities. OTA finds that improved simulation training for air traffic controllers is potentially more cost-effective than present programs.

As NAS becomes more fully automated, personnel who maintain NAS equipment will require more

sophisticated training. Moreover, planning realistically for maintenance personnel needs early in the

technology development process is important. Past

reductions in facilities technician ranks have made

maintaining aging ATC equipment difficult. Conditions at the FAA Academy are not conducive to

attracting first-rate instructors to train a new generation of airway facilities maintenance personnel,

and maintenance training is an afterthought in the

technology development process.

OTA concludes that support and funding from

FAA headquarters for immediate and long-term

programs to upgrade inspector, controller, and

technician training are vital to ensure a trained

work force capable of handling future system

safety needs. Congress may wish to consider legislation to permit hiring of retired personnel to

maintain sufficient levels of expertise. Furthermore, Congress may wish to encourage FAA to

raise the grade levels of instructors at the Academy and institute policies to allow easier movement between the field and the Academy.

Technological advances and changes in the aviation industry bring new aircraft technologies that

are beyond FAA expertise for ensuring adequate

safety standards. Furthermore, aircraft maintenance

procedures have changed substantially, and FAA

does not have adequate numbers of expert technical personnel or training capabilities for new staff,

nor does it have funding available to attract them

from industry. FAA programs such as Project

SMART

7 and National Resource Specialists are

steps to address this issue, but FAA must rely on

competence and professionalism in the manufacturing and operating industries to ensure airworthiness

of commercial aircraft. The future will continue to

bring new and increasingly sophisticated commercial aviation technologies, many of which will be

Tproject SMART is a plan to upgrade the Federal Aviation Administration’s aircraft certification regulatory program.
19

introduced not for the sake of safety, but for the

economic benefits they promise. Nonetheless, if introduced in the proper way, many hold the potential for decreasing the risk of an accident. OTA

finds that, in the long term, FAA will need greater

expertise on its staff in areas of new aviation technology to provide oversight comparable to today’s. Congress may wish to consider making

funding available specifically to bolster FAA’s expert technical staff.

TECHNOLOGIES TO ENHANCE SAFETY

Historically, technological advances have contributed greatly to increasing safety. While further safety

advancements through technology will be relatively

costly, OTA concluded that several technology areas

show real promise for improving safety, even as demands increase on the air system.

Severe weather is a contributing factor in many

aircraft accidents, and the most common types of

fatal weather accidents involve either windshear

near the ground or icing prior to takeoff. Sensors

such as Terminal Doppler Weather Radar (TDWR)

hold potential for rapid detection of dangerous windshear. However, TDWR’s great expense suggests that

other, less expensive technologies could be examined for use at smaller airports to augment the enhanced Low Level Windshear Alert System. In

addition, OTA concludes that training programs

for pilots in recognizing and coping with severe

weather, such as windshear, could be required for

all commercial pilots. An R&D program in cooperation with industry to improve icing detection

and de-icing of aircraft before takeoff and an improved cockpit crew training program for winter

flying are other priorities.

Furthermore, current air/ground communications

are not adequate in some cases to support pilot needs

for both real-time ATC and real-time weather information. Providing ATC information to ensure

separation between aircraft in the air and alert aircraft flying too low to the ground is the controllers’

first priority. At times controllers are too busy to

transmit weather information to pilots or are distracted from transmitting information by more urgent demands to separate traffic. Pilots need better

weather information in the cockpit, and programs

to develop message formats and workable air/

ground communications for weather information are

important immediate safety needs. OTA finds that

rapid development and operational testing of

alternative approaches to air/ground communication of weather information in parallel with

weather sensor development would improve

safety. For the longer term, digital air/ground data

links with an appropriate level of automation can

remove controllers from the process of relaying

weather information to pilots, thus reducing controller workload. However, the human factors issues related to automated, digital communications

for both controllers and pilots are not well understood. OTA concludes that R&D efforts on data

link services, human factors, and system integration have a potentially high payoff for efficiency

as well as safety.

Midair collisions account for about 5 percent of

all fatal accidents involving airlines and about 10

percent of fatalities. The Traffic Alert/Collision

Avoidance System (TCAS), the technology chosen

by FAA for backing up the ATC system in collision avoidance, will help to eliminate these accidents. TCAS warns pilots only of nearby aircraft

with operating transponders. Recent legislation requiring transponders for aircraft operating in terminal airspace where radar service is provided will

enhance TCAS effectiveness in preventing collisions. TCAS has taken years to reach readiness for

operational testing, due to the time required for technology development, testing, and certification. Because TCAS-II, required for commercial airlines in

recent legislation, advises the pilot of vertical ma- ,

neuvers only, efforts are underway to prepare

TCAS-III, which suggests both horizontal and vertical maneuvers. Yet unknown are human factors

and ATC issues that may be associated with widespread use of TCAS, although none of these issues

appears to be a crucial stumbling block to TCAS

implementation.

Although the United States has had few fatalities from collisions on the airport surface, a number of nonfatal collisions and close calls have

occurred. As air traffic levels climb, the probability
20

of a disastrous ground collision may increase unless compensatory steps are taken. OTA finds that

ground safety could be improved by more uniform

sign symbols on the airport surface, control lights

at entrances to active runways, and procedural

and training programs for pilots and controllers

on ground safety. Surface detection radar upgrades, such as FAA’s planned ASDE-3 radar,

which presents ground traffic information to controllers, are important safeguards against ground

collisions at larger airports. These radars can be

enhanced to provide conflict alert to controllers and

can eventually be integrated with digital air/ground

communications to provide alerts directly to pilots.

Congress may also wish to require exploration of

low-cost programs such as signs and lights. Eventually, advanced display and communications systems and new types of sensors may also improve

ground safety.

For the long term, although a program is underway to automate ATC through the Advanced

Automation System, serious questions remain regarding the degree to which the goals of this program will be met, as well as about the human factors aspects of automation. Further examination

of the potential hazards and efficiency gains resuiting from automation of controller functions

could clarify whether the Advanced Automation

System will meet its goal of safe control of higher

traffic levels. OTA concludes that such research

is a priority for FAA attention.

R&D Management

Schedule slippages and cost overruns in NAS Plan

programs are not unusual for a government program

of its size and technological complexity. However,

FAA’s management of technology development

for the NAS Plan could be improved. More attention could be focused on rapid development of

safety-critical NAS upgrades in areas such as air/

ground communications and ATC facilities. For the

longer term, more emphasis is needed on life-cycle

planning to include adequate time for system development and testing to meet the ultimate goal of

the NAS Plan: to provide the means for NAS

users—pilots and passengers—to fly safely and efficiently. Internal FAA coordination and management incentives need to be clearly tied to this goal.

Recognizing that important near-term needs exist, FAA has established an interim support program for NAS. However, FAA has done relatively

little near-term or longer-term research to support

NAS developments. The new operations research

and analysis effort known as the NAS Performance

Analysis Capability deserves continued support.

Such efforts can help FAA identify emerging ATC

problems and parameters for solutions to the problems. Prototyping and test bed technologies to help

evaluate technological and operational alternatives

are important to investigate more fully ways that

encourage innovation and timely fielding of technology.

FAA SAFETY DATA PROGRAMS

Commercial aviation accidents are such rare

events that statistically valid trends often require

at least 5 or more years of data. Accident data thus

have limited value over short periods of time or for

forecasting trends, and OTA concludes that the immediate effects of policy decisions cannot be monitored by short-term accident data. For example, the

consequences of recent requirements for collision

avoidance and transponder equipment will not appear in the accident data for many years.

Nonaccident data, however, can be used for shortterm safety analyses, and FAA programs collect or

have available to them a great deal of data for monitoring and assessing safety. However, while three

separate FAA divisions have safety data responsibilities, databases, data terminology, and automated

systems are often incompatible. Additionally, the

agency uses most of its databases for recordkeeping

and not for analysis and does not adequately emphasize accuracy or consistency, OTA concludes.

The few FAA studies that use nonaccident data

appropriately have come from the Office of Aviation Safety, and for the most part address such FAA

concerns as near midair collisions and air traffic controller errors. Four data areas—aircraft mechanical

reliability, airline operating practices, inspection results, and the financial condition of airlines—contain

helpful information for analysis. However, the ef-
21

fects on safety of airline practices, or changes in

them, are rarely addressed in FAA studies, although

FAA principal inspectors have a good understanding of their respective air carriers’ safety approaches.

A program to consolidate and communicate the

knowledge through consistent, centralized records

on the number, extent, or results of air carrier inspections could enhance safety. OTA finds that automating inspector recordkeeping and allocating

resources to ensure that the system, including

training, meets the needs of the field offices are

important priorities for the Office of Aviation

Standards.

Airlines themselves keep vital safety information,

and FAA could benefit from working more closely

with airline data, although ensuring the confidentiality of the air carrier data is crucial. FAA could

encourage improved air carrier reporting of sensitive safety data, such as incidents, by guaranteeing that no penalties will result from reported

information and by making nonreporting a violation. Additionally, access to airline computer systems, such as maintenance management systems,

could enhance FAA’s monitoring capabilities. One

major airline already provides FAA with on-line access to its computerized maintenance database.

OTA finds that across FAA the management

structure for data responsibility needs review, and

that coordination of efforts by the Offices of Aviation Standards, Air Traffic, and Aviation Safety

could promote a system safety approach. The data

systems themselves could be significantly improved

and coordinated with active participation by data

managers, analysts, and field personnel in all three

sections. OTA concluded that system safety would

benefit if the Office of Aviation Safety played a

coordinating and supporting role to Air Traffic

and Aviation Standards efforts, rather than continuing its present emphasis on investigation and

oversight.

Incorporating human factors needs into planning

and procurement is an important component of system safety management. Historically, aviation accidents have declined after major technology advances, prompting reliance on technological

solutions for safety problems. However, regulations

governing training programs for cockpit crews are

20 years old and do not include changes appropriate to some advanced technologies. At present, numerous and substantial changes to airline training

programs are covered by exemptions to Federal

Aviation Regulations, granted on a case-by-case basis with little analytical support. OTA finds that

FAA’s regulatory program has not identified or

addressed many training issues that are crucial to

ensuring safety. Congress may wish to direct FAA

to allocate resources and management personnel

to develop guidelines and advisories for revising

training standards and cockpit certification methods. Close coordination with ATC and controllers

is imperative. Key areas for federally supported research or regulatory efforts include operational data

collection, physiological and psychological factors,

crew management, and optimal use of automation

in the cockpit and in ATC facilities.
Chapter 2

m .

Airline Economic Context

Discretionary maintenance is an economic decision,
CONTENTS

Page

Commercial Air Transportation—Major Changes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

Growth in the Industry . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26

Consolidations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . 27

Aircraft Acquisition. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

Regional Airlines. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ....... 29

Shift Away From Open Entry . . . . . ........ . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

International Ties . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .... 32

Operational Changes .. .. .. .. .. .. .. ... ... ....... .. .. . .. .. .. .. .. ... ...... 32

Hub and Spoke Service . ............... . . . . . . . . . . . . . . . . . . . . . . . . ........ 33

Code-sharing . . . . . . . ........ . ............... . . . . . . . . ........ . . . . . . . . . 33

Computerized Reservation Systems (CRS) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

Controlling Costs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. .... 34

Profit and Debt Trends . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35

Policy Issues Related to Industry Changes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36

Airport Capacity . . . . . . . . ....... . . . . . . . ........ . . . . . . . . . . . . . . . . . ..... 36

Demand Management. . . . . . . . . . . . . . . . . . . . . . . . . . ........ . . . . . . . . . . . . . . . . . . 38

Effects of Consolidations on Employees . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39

Federal Labor Policy Changes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39

Public Policies Affecting Airline Operations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40

Air Traffic Controller Strike in 1981 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40

Federal Budget Cutbacks and FAA Inspection Program . .............. . . . . . . . 40

Environmental Concerns . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ....... . . 41

Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. ... ... .. .... .. ... . 41

Box

Box Page

2-A. Airport Scheduling Meetings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37

Figures

Figure Page

2-1.

——

2-2.

2-3.

2-4.

2-5.

2-6.

Scheduled Airline Passengers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ........ . . . . . . 27

Air Traffic Activity at Selected Hubs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

Large Aircraft in Commercial Service. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

Industry Market Share: Revenue Passenger-Miles . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

Expense Indicators of Major Airlines, 1978-1986: Labor and Maintenance . . . . . 34

Net Profits of Major Airlines, 1986 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36

Tables

Table Page

2-1. Commercial Aviation Traffic Statistics, 1986 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

2-2. Regional Airline Revenue Passenger-Miles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

2-3. Percentage of Passengers Enplaned by Airlines at Selected U.S. Airports . . . . . . 32
Chapter 2

Airline Economic Context

Over the last 10 years, many aspects of the commercial aviation industry have changed profoundly

as carriers seized opportunities offered by economic

deregulation. Airlines that once changed routes and

fares infrequently now serve a wide array of markets, offering competitive fares and frequent flier

awards to attract passengers. While the public enjoys lower fares and expanded service in some markets, concerns about airline safety focus on how

airline managements balance maintaining safety procedures and controlling operating costs.

Prior to passage of the Airline Deregulation Act

in 1978, the Civil Aeronautics Board (CAB) supervised the economic life of the industry, controlling

entry of new airlines, establishing routes carriers

could fly, and setting fares. CAB made such decisions after hearings and negotiations that often took

months and even years to complete. During the

hearing process, CAB members considered the economic effects of any requested change on the carrier, competitors in that market, airport operations,

and the interests of the public. This comprehensive

economic management ended when Congress dismantled CAB with the expectation that the public

would benefit from a less regulated industry—one

easier to enter and more responsive to price competition.

Understanding the current economic and institutional context of this complex industry, now disciplined primarily by market forces, is important

background for evaluating safety issues and the Federal role. Thus, this chapter reviews the airline

industry’s growth and major structural and operational changes that have occurred since deregulation, explores public policies that affect the airline

industry and safety issues, and concludes with the

economic outlook for the industry.

COMMERCIAL AIR TRANSPORTATION–MAJOR CHANGES

Commercial air transportation includes flights by

scheduled large jetliners, smaller commuter planes,

and air taxis, as well as cargo and charter jet service. Each industry segment has substantially different safety and economic effects on the aviation system. Although subdivided differenty by the Federal

Aviation Administration (FAA) and the Department of Transportation (DOT), the two broad categories of airlines of concern to this report are:

● 14 CFR Part 12 l—operations of aircraft with

more than 30 seats or 7,500 payload-pounds;

● 14 CFR Part 13 5—operations of aircraft with

30 seats or fewer. 1

Part 121 is usually associated with the major carriers and Part 135 with the commuter airlines.

OTA estimates that 450 million passengers traveled on all commercial flights in 1986, as shown in

table 2-1. Large airlines operating under Part 121

‘ These definitions can be confusing; 14 CFR 241 and 14 CFR 298

(and the general public) apply the terms “commuter” or “regional” to

scheduled operations of aircraft with 60 seats or fewer.

carried 95 percent of the passengers and accounted

for 99 percent of the revenue passenger-miles, Part

135 commuter airlines transported 4 percent of the

passengers and air taxis only 1 percent. Figure 2-1

shows the trends in passenger levels for the scheduled industry segments for each year since 1975.

While passenger statistics are one good way to

measure commercial aviation, other data are needed

to assess its effects on the air traffic control (ATC)

system. For example, commuter airlines and air taxis

have a much greater impact on airports and air traffic than passenger data indicate, because small propeller-driven aircraft take up nearly as much air and

runway space as wide-body jets. Therefore, data on

aircraft departures are needed to ascertain the relative impact of each industry category on the national

airspace system. Commercial air transportation operations (takeoffs and landings) at U.S. airports with

FAA control towers have reached record levels each

year since 1984, with commuters and air taxis

accounting for one-third of those flights.2 Because

J Air traffic controllers, who record data on traffic operations, do

not differentiate commuters from air taxis or Part 121 commuters from

25
26

Photo credit: Boeing Commercial Airplane Co. Photo credit.’ Fairchild Aircraft Corp.

Carriers operating large jets (left) are governed by 14 CFR 121, while commuter airlines flying

smaller aircraft often follow 14 CFR 135.

Table 2-1 .–Commercial Aviation Traffic Statistics, 1986

Passengers Revenue Aircraft

en planed passenger-miles Aircraft departures flight hours

Industry category (millions) (billions) (millions) (millions)

Part 121

Scheduled 121 . . . . . . . . . . . . . . . . . . . 418.5 366.3 6.4 9.4

Nonscheduled 121 . . . . . . . . . . . . . . . . 7.3 12.3 0.2 0.4

Part 135

Scheduled 135 (commuters) . . . . . . . 18.3a2.5a2.4 2.3a

Nonscheduled 135 (air taxis) . . . . . . . 6.5b

1 .0b2.5b2.9

Total. . . . . . . . . . . . . . . . . . . . . . . . . . 450.6 382.1 11.5 15.0

%TA estimate based on Regional Airline Association data.

bOTA estimate based on National Air Transportation Association and other air tmi data.

SOURCE: Office of Technology Assessment based on Federal Aviation Administration and National Transportation Safety Board published data unless otherwise noted, as of January 19S8

general aviation (GA) activity has declined substantially, total traffic nationwide is still below the peak

of 69 million operations reached in 1979. Although

GA and military flights generate a large volume of

traffic nationwide, they represent only a small portion of the operations at the largest and busiest

airports-less than 6 percent at Chicago O’Hare and

Atlanta Hartsfield, for example. The traffic growth

at four post-deregulation hubs, shown in figure 2-

2, illustrates how commercial airline traffic has increased rapidly and now dominates these airports,

while GA has held steady or declined. (The small

(continued from previous page)

Part 135 commuters. Additionally, since many air taxis are similar to

general aviation aircraft, an air taxi operation probably will not be

counted as such unless it is so indicated in the flight plan. Therefore,

air taxi operations are most likely underestimated by these statistics.

declines in 1987 airline traffic at Detroit and St.

Louis are results of airline mergers, rather than travel

reductions.)

Since most commercial aircraft operate under instrument flight rules, en route radar operations have

reached new peaks each year since 1984. Currently,

commercial transport operations account for over

60 percent of the workload for en route traffic controllers. For further discussion of air traffic issues

see chapters 5 and 7.

Growth in the Industry

The commercial airline industry has grown at an

unprecedented rate since deregulation. Although

growth has been sporadic, between 1979 and 1986
27

Figure 2-1 .—Scheduled Airline Passengers

I

i

250

150

100

50

0

I

‘1975 76 77 78 79 60 81 82 63 64 65 86 87

Year

m Scheduled Part 121 m scheduled Part 135°

apa~ 135 ~a~~enger counts estimated by the office of Technology Assessment,

NOTE: Nonscheduled 121 and 135 carriers increase the total by about 3 percent

for recent years.

SOURCE: Office of Technology Assessment baaed on Federal Aviation Administration and National Transportation Safety Board data.

air travel measured by revenue passenger-miles on

scheduled Part 121 flights expanded from 226.8 billion to 366.3 billion, a total of 62 percent. During

the last decade, takeoffs and landings of commercial airlines including both Parts 121 and 135 flights

have increased from 13 million to 19 million annually. Although the industry has recently consolidated dramatically, 119 new air carriers entered the

market between 1978 and the end of 1986. Also,

the number of commercial aircraft has increased substantially during the 1980s. As shown in figure 2-3,

commercial carriers added 1,007 large jets to their

fleets between 1980 and 1987 for a 42 percent increase and are expected to have a total of 3,528 in

1988. New orders indicate fleets will continue to expand in the next couple of years.

The country’s economic boom between 1983 and

1987 was partially responsible for these robust

growth figures; however, the absence of economic

restraints also encouraged airlines to expand services and to become more competitive. Moreover,

these factors set the stage for structural and operational changes in the airline industry.

Consolidations

By 1987, the independent carrier, once the industry’s principal structural unit, had almost disappeared, replaced by large financial organizations that

control several airlines and/or affiliates and have

broad ties to the national financial network.

Nonetheless, ownership changes, reorganizations,

failures, or threats of takeovers among U.S. airlines

still occur occasionally. On the other hand, some

industry characteristics have come full circle since

deregulation, and many factors now exist that make

it almost as difficult to enter the business today as

it was prior to 1978, except in specialized market

niches.

Despite the large numbers of new carriers entering business in the early 1980s, rapid consolidation

has occurred in the aviation industry during the last

3 years. The recent mergers and takeovers apparently conclude the decade-long debate about how

deregulation would affect the structure of the industry and support those who forecast a consolidated

industry with many trappings of an oligopoly. (Oligopoly is an economic term meaning there are only

a few producers of a product, and little or no

differentiation exists among products or price.)

All the larger passenger air carriers that existed

in 1985 have been involved in some sort of a consolidation; three mergers involving major and national carriers occurred in 1985, eight in 1986, and

one in 1987. The recent slowdown in the frantic

activity of the last 3 years is a result primarily of

the small number of remaining merger candidates.

Fewer firms control more of the industry’s traffic

now than in 1978, when the industry’s eight largest

firms enjoyed 81.5 percent of industry’s traffic. By

1984, the percentage of passengers carried by the

eight largest firms had dropped to 76.3 percent, and

many industry analysts were convinced that the major airlines were losing some of their market power

and that new carriers would play a growing role.

However, by 1986, the industry had concentrated

as a result of mergers and acquisitions, and the top

eight carriers controlled 88.4 percent of the market

(see figure 2-4). By the end of 1987, the eight largest

airlines had increased their market share to over 92
28

Figure 2-2.–Air Traffic Activity

100

0

“1975 767778796081 82636465668 7

Year

100

o

1975767778796081 62636465668 7

Year

_ Air carrier ~ Air taxi ~ Military/general aviation

200

100

0

197576 77 78796081 62636465668 7

Year

---

200

100

0

1975767778796081 62636465668 7

Year

SOURCE: Office of Technology Assessment based on Federal Aviation Administration data.
29

Figure 2-3.—Large Aircraft in Commercial Service

1 1 1 r 1 1 1 1 ,

19801981198219831984 198519881987 1988a

Year

a

Forecast.

SOURCE: Office of Technology Assessment based on Federal Aviation Administration forecasts, fiscal years 1986-1997.

percent, not including the traffic carried by regional

affiliates.

To reach this degree of concentration, airlines reorganized through mergers or acquisitions. In the

case of Texas Air, the holding company acquired

two airlines—Eastern and Continental—which it

operates as semi-independent units under its corporate umbrella. One of these units, Continental,

has absorbed Frontier, People Express, and New

York Air through mergers and acquisition. AMR,

the American Airlines parent organization, owns

the airline and several smaller carriers, and also operates Sabre, a computerized reservation system, as

a separate subsidiary. Holding companies do not always manage similar or related companies, frequently selecting their subsidiaries as much for profitability as comparability. The significance of the

holding company structure lies in the dual responsibility the airline management has for its operations

as well as to the economic goals of the parent organization.

Aircraft Acquisition

Two trends in aircraft acquisition signal major

operating changes for the industry. First, changes

in the tax laws have made leasing equipment a more

attractive option for airlines.3 Firms such as Delta

and Northwest, which have in the past owned most

of their own aircraft, now lease some of their fleets.

If growth in leasing activity continues, a large part

of the domestic fleet could be the property of leasing companies and aircraft manufacturers. This

more flexible arrangement reduces the carriers’ longterm capital commitments and limits financial risk,

an advantage if the industry experiences an economic downturn and finds itself with excess planes.

Leasing equipment also changes the way some airlines manage maintenance (for further information,

see chapter 5).

Second, competition for sales among the world’s

three major commercial transport manufacturers,

Boeing, McDonnell Douglas, and Airbus, is fierce,

and as a result they are willing to make favorable

deals for carriers. American has negotiated an order split between Boeing and Airbus in which the

manufacturers are leasing the equipment with generous renewal and cancellation provisions. Northwest

has placed a major order with Airbus with the right

to cancel any part of it on an annual basis without

penalty. Also, manufacturers are including additional training and equipment maintenance service traditionally performed by carriers as part of lease

or purchase deals. The long-term effects on safety

of the manufacturers’ willingness to offer service,

training, and creative financing to make sales are

not entirely clear, but in the short run it ensures

new orders and an increase in available aircraft to

the major carriers.

Regional Airlines

Spurred by deregulation, many small regional airlines entered the market in the early 1980s. Simultaneously, major airlines sought to extend their high

density markets by increasingly dominating their

hubs and sloughing off less profitable routes. Their

actions encouraged regional airlines to provide service linking small cities and providing connections

to hub airports. Because regional carriers use smaller

aircraft and require less ground-based infrastructure,

they can often operate such routes more profitably

than the majors and provide a needed service.

‘ Joan M. Feldman, “Airlines Learn To Cope With Tax Reform,”

Air Transport World, May 1987, p. 42.
30

Figure 2-4.—industry Market Share:

Revenue Passenger-Miles

1979

American

.-

1986

United

SOURCE: 1979: Market share based on revenue passenger-miles (RPMs) of U.S. airllnes performing scheduled service (228.8 million) as reported in Air Transport Association, “Air Transport 1979,” June 1, 1979, pp. 20-21; 1984: Market share based on RPMs of U.S. airlines (296.3) milllon as reported In Atdatiorr Dally, “lndustw

Market Share,” Feb. 5, 1988, p. 200 (reverse); 1988: Market share based on RPMs of US. airlines (360.7 million) as reported in AvMorr Da//y, “Industry Market

Share,” Jan. 30, 1987, p. 150 (reverse).

As illustrated in table 2-2, the major increase in

revenue passenger-miles for regional carriers occurred between 1978 and 1984; growth since 1984

has been relatively flat, increasing only 1 percent

between 1985 and 1986. Also the number of regional

carriers has dropped from a high of 250 in 1981 to

the current level of approximately 150.4

4 U.S. Department of Transportation, Federal Aviation Administration, Planning Analysis Division, FAA Aviarion Forecasts, Fiscal Years

J987-1998 (Washington, DC: U.S. Government Printing OfYice, 1987),

p. 50.

Table 2.2.—Regional Airline Revenue Passenger-Miles

Revenue passenger-miles

Year (in billions)

1978 . . . . . . . . . . . . . . . . . . . . . . . .

1979 . . . . . . . . . . . . . . . . . . . . . . . .

1980 . . . . . . . . . . . . . . . . . . . . . . . .

1981 . . . . . . . . . . . . . . . . . . . . . . . .

1962 . . . ... , . . . . . . . . . . . . . . . . .

1983 . . . . . . . . . . . . . . . . . . . . . . . .

1984 . . . . . . . . . . . . . . . . . . . . . . . .

1985 . . . . . . . . . . . . . . . . . . . . . . . .

1986 . . . . . . . . . . . . . . . . . . . . . . . .

1.36

1.72

1.92

2.09

2.61

3.24

4.17

4.41

4.47

SOURCE: Office of Technology Assessment based on 1987 Regional Airline Association data.
31

The recent low growth in traffic and the attrition

among regionals can be explained in part by the absorption by the majors of regional carriers through

acquisition or affiliations. Although some regionals,

such as Ransome, have been acquired by major carriers, the more pervasive trend has been for the regional to establish an affiliation with a major carrier

and feed traffic to its hub airports. As an affiliate,

the regional is dependent on the major for marketing—usually sharing the major’s code on published

airline schedules and in computer reservation systems. The dependency is accentuated if the major

also provides an affiliate with aircraft maintenance,

fuel, and other essential services. Some majors try

to raise the safety standards of regional affiliates by

requiring an upgrading of operational standards as

well as training and maintenance policies and procedures. While such arrangements are highly desirable for the major, enabling it to extend its market

without appreciable capital expenditure, many

regionals are dependent on their major carrier and

fail if they lose their affiliation. Moreover, some localities have complained that regional airlines are

more interested in satisfying the major carrier than

in providing for community needs.

Lack of airport access is another factor contributing to the recent decline of regional carriers. Congestion at their hub airports has prevented some

regionals from maintaining the on-time schedules

needed to retain customers.5

Furthermore, plans

are in the works at some busy airports to reduce

the number of regional flights served, as part of efforts to use runway capacity more efficiently.

As regional carriers find competition increasing

for access to hub airports, the safety standards of

local airports that serve small (Part 135) aircraft are

being questioned. Currently, airports receiving their

only scheduled service from Part 135 carriers are not

eligible for certification under the FAA Certification Program. Certification requires airports to meet

minimum standards for equipment and operations

and to develop procedures to minimize loss of life

and property in the event of an accident. A recent

General Accounting Office study recommends that

certification be required for all airports that receive

5 OTA confidential airline survey.

regularly scheduled service, regardless of the aircraft

size.6

Shift Away From Open Entry

A major argument in favor of deregulation was

that CAB oversight had discouraged the entry of

new firms into the industry and had created a

government-regulated oligopoly. Yet of the 119 carriers that entered the industry between 1978 and

1986, only 35 were still operating at the end of

1986.7

The demise in 1986 of People Express, the model

for carriers formed in the early 1980s, signaled the

end of open entry in practical terms. Like some other

new entrants, People Express had counted on an

expanding market to finance the major maintenance

needed after 2 to 3 years of operation. Head to head

competition from established carriers in cities like

Buffalo prevented buildup of capital, and for this

and a host of other reasons, People’s management

was forced to seek a buyer to avoid bankruptcy, So

many individual and institutional investors lost

money on People and other new entries, and so few

of the young firms still operating have provided attractive returns on investments, that Wall Street

capital markets for new entrants are now essentially

closed. 8

Furthermore, would-be entrants now find many

principal airline markets effectively closed. Existing

hub operations cover most logical transfer points

that also produce significant local traffic, and few

opportunities remain to establish hubs at underutilized airports in major cities, as Midway did in

Chicago. New entrants are further discouraged by

the dominance of one or two carriers at hub airports as shown in table 2-3. The carriers that dominate in these hubs are fiercely protective and will6 U.S. Congress, General Accounting Office, Aviarion Safety–

Commuter Airports Should Participate in the Airport Certification

Program, GAO/RCED-88-41 (Washington, DC: U.S. Government

Printing Mice, November 1987), p. 9.

7 Frank A. Spencer and Frank H. Cassell, Northwestern University

Transportation Center, “Eight Years of U.S. Airline Deregulation: Management and Labor Adaptations; Re-emergence of Oligopoly,’) unpublished manuscript, January 1987, p. 37.

‘Julius Maldutis, Solomon Brothers, unpublished manuscript of address at the Aero Club of Washington, DC, June 23, 1987.
32

Table 2-3.–Percentage of Passengers Enplaned by

Airlines at Selected U.S. Airports

Passenger

Airport Air carrier(s) percentage

Atlanta

Charlotte

Chicago O’Hare

Dallas/Ft. Wortha

Denver a

Memphis a

Minneapolis

Pittsburgh

St. Louis

Delta, Eastern

Piedmont

United, American

American, Delta

United, Continental

Northwest

Northwest

USAir

TWA

93.7

81.2

72.6

85.9

86.9

74.6

79.9

82.5

82.9

apercentage includes totals attributed to merger and consolidation Partners.

SOURCE: Aviation Dally, “U.S. Carrier Market Share at Leading U.S. Airports, ”

June 3, 19S7, p. 353 reverse-3S0 reverse.

ing to cut fares for as long as it takes to prevent a

new carrier from establishing itself.

Furthermore, obtaining gate and terminal space

is expensive, even where it is available; in many airports, the best gates and terminal counter spaces

are leased on a long-term basis by major carriers.

At capacity controlled airports, the cost of slots

forms another deterrent–at Washington National

and New York LaGuardia, slot costs are being

quoted at $1 million each.9

Finally, aircraft procurement expense is a formidable hurdle facing a new carrier. Most of the new

entrants during the early 1980s acquired their fleets

when prices for new and used aircraft were depressed

because of the recession. Today, used aircraft in good

condition draw premium prices, and new jets cost

well over $20 million.

International Ties

The U.S. airline industry is increasingly linked

to the international market, and it is reasonable to

expect that marketing and other financial ties be-

‘ Aviation Daily, “American West Asks FAA To Reallocate Slots

at National, LaGuardia,” July 2, 1987, p. 10.

tween the United States and other countries will

grow over the next few years.l0 Some U.S. airlines

have found that low labor costs in some foreign air

hubs make deploying some major maintenance

abroad extremely cost-effective. At least two countries, Sweden and Canada, have proposed that cabotage restrictions between their nations and the

United States be dropped. (Cabotage refers to the

practice of preventing foreign carriers from flying

U.S. passengers to more than one domestic destination on a single trip. For example, a Swiss flight

from Zurich cannot fly to New York, pick up passengers and continue to Cleveland. It could, however, drop off New York passengers and then fly,

half full of remaining passengers, to Cleveland, if

it had bilateral permission to do so.) So far the

United States has rejected these overtures, contending that the United States has more to lose than

to gain by offering complete freedom of entry. However, future innovative marketing arrangements between carriers may modify arrangements between

international carriers. Moreover, foreign airlines

may participate directly in the U.S. industry through

investment. Ansett Transportation Industries, Ltd.,

one of Australia’s three major airlines, recently announced a plan to purchase 20 percent of American West Airlines stock—the largest percentage

holding by any foreign airline in a U.S. domestic

carrier. (Up to a 25 percent interest by foreign investors is allowed by U.S. law.) As part of the deal,

Ansett will have one representative on the American West board, can establish links with its existing U.S. freight forwarding service, and will gain

expertise in deregulation for when Australia deregulates its airlines.ll

10 Aviation Dai]y, “Analyst predicts Worldwide Airline 1n%ratlOn,”

Mar. 18, 1987, p. 403. I I Michael A. Dornhelm, “Ansett’s Stock Purchase Will place Foreign Stake in American West at 20 Percent,” Aviation Week and Space

Technology, July 20, 1987, p. 41.

OPERATIONAL CHANGES

Now that the marketplace determines profits, air- in air travel have been achieved by price competilines have moved aggressively to expand market tion, expanding service into new markets, and adshare and to hold down costs. The annual increases justing service to meet consumer demands. To con-
33

trol costs, managements have reduced staff and

instituted a variety of tight cost management

methods.

Hub and Spoke Service

Airlines have tried to maximize passenger seats

filled by eliminating unprofitable routes and concentrating on lucrative high-density routes serving

large- and medium-sized airports. The hub system

establishes a number of routes connected to a central hub airport where passengers are collected from

feeder flights, transferred to other flights on the same

line, and are then carried to their ultimate destination. The traffic pattern at a hub airport consists

of closely spaced banks of arrivals and departures.

Passengers land at the airport and transfer to

another flight within 40 to 50 minutes. Although

Delta used Atlanta as a hub long before deregulation, most of the other majors adopted this pattern

during the 1980s, because it permits service between

more origin and destination points. Moreover, passengers can be retained by the airline for longer distances, raising the average revenue per passenger.

In most cases, carriers choose a busy airport as a

hub, so they can offer passengers a wide variety of

possible connections as well as capitalize on already

heavy origin and destination traffic. About threequarters of the passengers at Atlanta and one-half

at Chicago, Denver, and Dallas-Fort Worth arrive

merely to change planes for other destinations.

While the shift of the major airlines from pointto-point service to hub and spoke has been a sound

marketing tactic, it has forced adjustments in personnel and procedures that have substantial costs.

Although hubbing allows carriers to centralize major maintenance facilities and inventory, aircraft

often require servicing at a spoke where the carrier

does not have repair capability. Contract arrangements may be made with another carrier for maintenance, or parts and repair crew may be flown in—

at considerable expense.

Because hub and spoke operations rely on tightly

scheduled arrivals and departures, congestion and

delay can occur during peak hours, especially at airports such as Chicago and Atlanta, that serve as

hubs for several major airlines. Moreover, the slots

at these airports are one half-hour time periods. To

maintain their position on computerized reservation

systems, airlines tend to cluster arrivals and departures in the first 10 minutes of their slots, intensifying demands on an already full ATC system. Bad

weather, requiring instrument flight rules, can make

delays much worse. The additional costs attributable to congestion and delay such as fuel, missed

connections, and customer dissatisfaction have

caused some airlines to establish hubs at less busy

airports, as Piedmont has done at Baltimore-Washington International. The largest carriers have established additional hubs at less busy airports, as American has at Raleigh-Durham.

Code-sharing

Code-sharing is a term that refers to two airlines,

usually a major and a regional carrier, that share

the same identification codes on airline schedules.

By code-sharing with a regional airline, a major airline can advertise flights to a much larger market

area and expand its market at relatively low cost.

Prior to 1984, code-sharing existed only on the

USAir-affiliated Allegheny Commuter service, but

by the first half of 1987, the principal regional airlines were all code-sharing partners with a major airline. Code-sharing agreements vary widely and may

include marketing and other tie-ins between the regional and major airlines, such as discount bulk fuel

purchasing and terminal counter and gate sharing.

Some of these agreements further lock in codesharing affiliates by providing training, pooled aircraft purchasing, and other types of services that

the regional could undertake only at much higher

costs. While code-sharing arrangements can be

mutually beneficial to both partners, the interdependence is often one-sided; the major is far less dependent on the smaller carrier than vice versa.

Computerized Reservation Systems

(CRS)

CRSs are computerized systems that display airline schedules and prices for use by agents in making reservations. They are potent marketing tools,

since approximately 90 percent of all reservations

made by U.S. travel agents are made through these

systems. Although five such systems are currently

owned and operated by major airlines, American’s
34

Figure 2-5.—Expense Indicators of Major Airlines,

Sabre and United’s Apollo account for 70 percent

of the market use. CRSs have been expanded to

make other types of reservations, such as hotel and

rental cars. Fees from sales made using the systems

are sources of substantial revenue and profits for

their owners,

Since CRS is programmed to select flights based

on published schedules, airlines find tremendous

economic advantages in developing schedules that

show flights to major cities arriving and departing

during the early morning and evening peak hours.

For example, to compete for lucrative business

travel, airlines bunch arrival times at major airports

at 8:30 or 9:30 a.m., in time for morning meetings.

DOT’s action to require airlines to report on-time

performance was designed in part to prevent airlines

from underestimating their actual flying time to gain

a more favorable position on the CRS.

Controlling Costs

To maintain competitive fares and still make a

profit, every airline has made intense efforts to reduce and control operating costs for labor, fuel,

maintenance, commissions, and other services.

Gone is the era when fares were controlled by CAB,

and cost increases could be passed on to the consumer without the threat of losing business to

another carrier.

Labor Costs.–Labor is the industry’s largest operating expense, representing 42.6 percent of total expenses in 1986 (see figure 2-5), down from the 1978

1978-1986: Labor and Maintenance

100 I

90

80

70

60 !

19781979196019611982 1983196419851966

Year

SOURCE: Office of Technology Assessment based on Congressional Research

Service data.

peak of 46.1 percent. (The 1981 low in labor’s share

of total costs reflects increased fuel prices rather than

significant reductions in labor costs.) Each airline

devotes a different portion of costs to labor. In 1986,

for example, Continental expended 22.8 percent of

operating expenses for labor, while among the other

majors, only Northwest at 28.4 percent spent less

than 31 percent of total expenditures on labor. 12

Continental achieved its low labor cost partially as

a result of its bankruptcy filing in 1983, which enabled it to nullify its existing union contracts. Setting an example soon followed by most major carriers, American initiated a two-tier pay structure in

1983 which paid new employees significantly less

than existing employees. The strategy held labor

costs down, but was very unpopular with employees, and has been significantly modified. After its

merger with Republic in 1987, Northwest refused

to raise pay levels for former Republic employees

to equal those of Northwest personnel, creating a

two-tier pay scale that was a persistent irritant.

Other airlines undergoing financial difficulties have

12 Aviation Daily, “Major and National Carriers Labor Expenses,”

July 15, 1987, p. 77 reverse.
35

negotiated employee pay cuts, generally the most

contentious issue in airline negotiations and acceptable to employees only when failure or bankruptcy

seem likely alternatives. Finally, airlines have reduced or eliminated positions, Several have eliminated meteorology and safety sections, others now

rely on manufacturers for engineering expertise that

used to be a part of the airline’s operations.

Some airline holding companies have established

nonunion subsidiaries that provide the same service at a lower cost than the carrier’s union employees. This strategy, known as “double-breasting,” was

initiated by New York Air and is considered reprehensible by organized labor. Attempts to form subsidiaries through the transfer of existing union workers to new firms have met with fierce resistance from

the affected unions. As the need has grown for

skilled pilots and ground personnel, management

has had to back off from severe wage and benefit

inequities.

Maintenance Costs.–Industry data reported to

DOT show that maintenance expenditures dropped

from a high of 14.5 percent of operating expenses

in 1978 to a low of 10.3 percent in 1982, a period

of high fuel costs, and then rose to 13.7 percent in

PROFIT AND

The last decade has contained both the industry’s

most profitable and least profitable years, not surprising given the extent of change within the airline industry. However, in a noteworthy departure

from conditions during the regulated era, the profits and losses associated with these cycles have not

been evenly distributed among the major carriers.

Even in good years for the industry, certain firms

have not fared well. In 1986, considered a profitable year for the industry overall, the vast majority

of the net profits were concentrated in about half

of the major firms (see figure 2-6). While all airlines

have cut costs, some have been more successful than

others in making money in a rapidly changing environment, and consistently, a few firms—American,

Delta, Piedmont, USAir, and Northwest–have

been more profitable than their competitors.

The leveling off and decline in interest rates has

helped the industry reduce the impact of a large debt

1986. Airline maintenance spending, which includes

refurbishing and remodeling aircraft as well as routine equipment maintenance, usually rises with industry profits that make available discretionary

funds. In hard times, airlines undertake only the

maintenance necessary to meet FAA standards.

Since individual airlines allocate costs differently,

conclusions about the safety impacts of maintenance

expenditure fluctuations are very problematic. For

further discussion see chapter 5.

Fuel Costs.–Fuel has been the most volatile cost

for the industry, swinging between a high of 33.9

percent of operating costs in 1980 to a low of 19.6

percent in 1986. The industry has little control over

fuel costs since it must generally pay prevailing

prices.

Commissions.–Airlines have increased expenditures for travel agent commissions, and almost 11

percent of total 1986 operating expenses were commission payments, up from 5.5 percent in 1978.

However, this shift occurred because airlines now

rely on travel agents, aided by CRSs, to capture business. Indeed, CRS programs are so effective that

many airlines have been able to reduce drastically

their ticket sales forces.

DEBT TRENDS

burden, which stood

1986.13 However, the

try time bomb. Some

at $15 billion at the end of

debt issue may be an indusfirms are earning enough to

service large debt, while others are able to service

their debt only by refinancing or taking other steps

to reduce the burden. The debt load, like net and

operating profits, is not evenly distributed among

firms in the industry. For example, Texas Air carries the industry’s largest debt, $4.7 billion, followed

by AMR with $2.4 billion, TWA with $1.9 billion

and Delta with $1 billion.14 Although debt is not

now a pressing problem, an economic slump could

push marginally successful carriers into dangerous

financial situations.

I 1 A “iatjon Daily, “Intelligence, ,,

ure does not include Piedmont.

‘q Ibid.

May 4, 1987, p. 185. Industry fig-
Figure 2-6.–Net Profits of Major Airlines, 1986

Northwest

USAir

. Continental

Western

United

TWA

Eastern

Pan Am

-500 -400 -300-200-100 0 100 200 300

Millions of dollars

SOURCE: Office of Technology Assessment based on Congressional Research

Service data.

POLICY ISSUES RELATED TO INDUSTRY CHANGES

The numerous operating changes and economic

considerations discussed in this chapter present difficult issues for public policy makers. Among the

most compelling are the problems of allocating

limited airport capacity in a safe, efficient, and equitable manner and the effect of mergers, reorganizations, and cutbacks on employee performance.

Airport Capacity

The majority of airports are small or regional facilities that have adequate capacity, and even at the

busiest airports, demand exceeds capacity only at

some times of day. However, because the demand

exceeds the runway and gate capacity of the busiest hub airports at peak hours, congestion and delays frequently occur even in good weather, and are

especially troublesome in bad weather. At those airports where capacity is an issue, every method of

meeting demand has significant operational, economic, and safety implications.

During 1987, the number of delays reached record levels at certain airports and on some airlines,

inconveniencing travelers throughout the system.

Especially hard hit have been some commuter airlines that tend to lose customers under circumstances of hub congestion, since, except for early

morning departures, they cannot maintain an ontime schedule.15 The industry blamed the limitations of the ATC system, while FAA countered that

while delay is often weather related, carriers’ hub

operations and CRS scheduling competition contributed to delay problems. (See box 2-A.) Passengers reacted with an all-time high in complaints. The

causal relationship between congestion and airline

safety is subtle and complex, and ground and airspace congestion place pressure on the ATC system, pilots, and aircraft equipment to operate with

special regard for safety, even though delays may

result.

15 OTA confidential airline survey.
37

Box 2-A.–Airport Scheduling Meetings

The Office of the Secretary of Transportation (OST) and airlines hold meetings when the number of delays

due to overscheduling or other factors becomes unacceptably high. The high-density rule of 19681 limited operations at five heavily used airports, Kennedy, O’Hare, LaGuardia, Washington National, and Newark. Industrygovernment scheduling committees were formed at each of the airports to meet regularly and resolve problems.

In the early 1980s, the scheduling process began to break down, with numerous resulting delays, and the Department of Transportation (DOT) issued a rule to allocate slots and permit their sale at Kennedy, LaGuardia,

O’Hare, and Washington National.2 Currently DOT now conducts scheduling meetings involving the Federal Aviation Administration (FAA), OST, and airline representatives when delays at these or other airports

become a major problem, although such meetings are not held on a regular basis. The first meeting was held

in November 1984 (the “Crystal City meetings”) and the second in the spring of 1987 to address the peak hour

problems at Newark, Philadelphia, Dallas-Fort Worth, O’Hare, and Atlanta. Another set of meetings was held

in late 1987 to prepare for a 6-month runway closure due to a major repair at Los Angeles.

Three causes create schedule peaks: hubbing operations; customer demand–although this is hard to isolate, and demand peaks may spread over 2 hours; and, probably most important, the computer reservation

system. Travel agents sell tickets according to the list of flights that appears on the computer screen. The listing

gives priority to flights with times nearest the requested time. Customers tend to request flights on the hour,

so most lists first show flights near the beginning of the hour. Flights farther away from the hour may not even

appear on the first screen or even the third at the busiest airports. Customers select the first flight on the list

more often than any other flight, and select flights on the first screen more often than flights on later screens.

Therefore, flights scheduled near the beginning of an hour have a marketing advantage over other flights. Even

the four airports with regulated slots ate subject to the peaking problem, because slot durations are at least

30 minutes, and airlines with slots can and do bunch flights on the hour.

DOT relies on FAA technical expertise to judge airport capacity. Capacity is an extremely complex issue

depending on weather, runway configurations, and noise restrictions. Airlines resent limits on scheduling and

sometimes dispute FAA procedures and capacity estimates, maintaining that air traffic control procedures need

to be improved, holding patterns better used, and separation standards reduced. They also would like to see

more airports and runways constructed.

FAA conducts the meetings, and, despite these airline complaints, tries to view the situation from the air

traffic control standpoint, warning the airlines that flow control will hold flights on the ground if overscheduling persists. OST is present at the meetings to guarantee anti-trust immunity by ensuring that no deals are

cut between carriers, and to represent the consumer viewpoint on the importance of maintaining schedules

and avoiding delays. In practice, OST has found it necessary to enforce its policy objectives through investigations and delay reporting rules. While investigations are still ongoing, in 1987 OST did achieve some of its

objectives—airlines have signed agreements to adjust their schedules at four airports that chronically had late

flights. Schedules at these far airports improved, although Atlanta remains a problem because a major airline

with a hub there would not agree to many changes in its schedule.

A similar meeting was held in Los Angeles to determine how to cope with the impending closure of one

runway for repair. After considerable deliberation, both major airline users agreed to reduce their schedules

for Los Angeles during the period of major work. Although participation in the meetings and implementation

of agreed upon changes are completely voluntary,3 one anonymous observer has likened them to auctions where

no one wants to bid.

’33 Federal Rq@ter 17896 (Dec. 3, 1968).

2

50 Fcdcrd Rcgistcr 52180 (WC. 20, 1985).

‘Cynthia Burbank, U.S. Dqwtment of Transportation, Of%ce of the Secretary, pmond conunudcadon, Dec. 4, 1987.

FAA innovations, such as the reconfiguration of Coast Plan, changes to ease delays for traffic between

airways under the East Coast Plan, are proof that New York and Washington adversely affected Philimproved management can increase capacity in parts adelphia. Physical improvements in airport facilities,

of the system. However, actions to alleviate one such as additional runways, may be a partial soluproblem often create another. In the case of the East tion to the capacity problem, but difficult issues re-
38

lated to noise and land use control preclude substantial relief in the near future. Technology can

increase the capacity of airports to a limited extent

by allowing fuller, more efficient use of existing facilities; actions for improvements are discussed in

chapter 7.

Demand Management

One approach to controlling congestion and delay is by managing demand; tactics include limiting access by restricting certain types of aircraft, pricing policies, and quotas or slot control. Prohibitions

such as those based on size work best in situations

where there is an alternative airport to which restricted carriers can be diverted. To forbid some portion of the traffic to use an airport without an available alternative is likely to be considered a restriction

of interstate commerce or discriminatory practice.

Officials of the Massachusetts Port Authority

(Massport) have recently proposed a plan for revising landing and terminal fees at Logan Airport that

would raise use charges for small aircraft to more

nearly equal those paid by large carriers and would

eventually add a premium to charges for peak hour

operations. The plan, to be implemented July 1,

1988, raises the base minimum landing fee from $25

to $88 and reduces the landed weight charge from

$1.31 per 1,000 lb. to $.47.’6 In effect, the plan increases charges for aircraft with 30 seats and fewer

while substantially reducing charges for large passenger jets. Massport estimates that while the pricing plan will reduce Logan operations by only 5 percent, it will cut delays up to 80 percent, because the

reduction of small, slower GA or commuter flights

can improve runway capacity. Similar aircraft can

be more uniformly and efficiently spaced on approach and departure, thereby smoothing out irregularities in the traffic stream, a prime cause of

delay.

Representatives for GA and regional airlines protested that the Massport plan is discriminatory,

and Massport has exempted from the proposed fee

changes regional airline flights from 14 New England communities that have “Essential Air Service”

to Logan. The Regional Airline Association claims

Iti Aviation week & Space T~hnol*gy, “Massport Passes First

Phase of Fee Increases at Logan,” Mar. 21, 1988, p. 75.

the plan will reduce or eliminate air service to most

of the other 30 cities served by regional airlines operating in and out of Logan. Whether FAA has the

authority to make a decision on the discriminatory

nature of the plan under Federal laws and regulations is likely to be tested in the courts. Regardless

of the outcome, the concept of restricting traffic

through pricing is one many advocate. Port Authority of New York officials are considering a large increase in the minimum peak hours fees for the three

airports they manage: Newark, Kennedy, and LaGuardia.

Quotas and Slot Sales.–Setting a quota on the

number of slots available at an airport is another

controversial approach to controlling airport demand. Limits on the number of operations or slots

per hour are based on the capacity of the ATC system, the airport runways, and sometimes local sensitivities to noise. Slots at most airports are allocated

through negotiations with a scheduling committee

consisting of the airlines, the air traffic controllers,

the airport management, and DOT. For example,

at Washington National, where 60 slots are available per hour, 37 are allocated to air carriers, 11 to

commuters, and 12 to GA aircraft. The system allows some flexibility for accommodating more flights

in good weather.

Slot sales are an experiment, initiated by DOT, to

allocate airport access through bidding. By auctioning slots, DOT provides access to those users willing to pay the highest price. Some economists argue

that if airport access must be limited, it should be

treated as a scarce resource and priced accordingly.

Critics claim the current slot sale process gives an

advantage to the airlines already operating at the

airport and denies access to competitors, providing

the existing users with virtual monopolies and a financial windfall. The airlines that control the slots

contend that the system is fair; since they took the

risk necessary to develop the market, they should

be rewarded by retaining the slots. Contrary to

DOT’s expectations, the slot sale plan has not

fostered an active market; available slots are scarce

and expensive, with 30 minute slots at Washington

National and LaGuardia recently selling for over

$1 million each.

Restrictions on aircraft by size or type and any

form of a quota system used to achieve greater air-
39

port efficiency raise important equity issues. Whose

access is restricted and why? Is the commuter airline denied access to the nearest hub airport because

of its small size or lack of funds to buy a slot? Will

smaller communities lose air service entirely because,

shut out of hub airports, the commuter airlines that

serve them cannot stay in business? Will the airlines

increase peak hour fares if airports charge premium

fees at peak hours, or will the increased costs be

spread among all the airline users to maintain competitive pricing for popular travel times? Experience

to date with slot sales raises questions about how

fairly market allocation of scarce resources like airport access can work.

Effects of Consolidations

on Employees

Since 1985, all the major airlines have been involved in some sort of consolidation, creating uncertainty, stress, and dislocation for many employees. Long-term employees accustomed to a secure,

regulated environment have been particularly affected. The exact extent to which airline employee

performance has been affected by stress related to

mergers and takeovers is beyond the scope of this

report. However, research indicates that reorganization is always stressful and often debilitating to

employees and destructive to company morale. Airline employees have had to deal with wage cuts, relocations, and the threat of job loss. Once confident

employees see career paths stymied and disturbing

changes in operating practices and the corporate

culture.

Psychologically, most employees of companies in

the process of management changes go through a

series of stages, called the “merger syndrome. ” After initial denial of the inevitability of change, they

approach the consolidation with fear and anxiety,

feelings that are replaced by anger and distrust if

the merger does not go well. ’7 In the last stages,

employees leave or adapt through a combination

of accommodation and resignation. Even in situations of “friendly” mergers, employees become absorbed and preoccupied with the reorganization. Job

performance lags, and attention turns to preparing

1; M.L. Marks and P.H. Mirvis, “The Merger Syndrome,” F’sychology Today, October 1986, p. 38.

resumes and talk about personal plans.18 Some employees suffer from physical symptoms of insomnia,

excessive nervousness, and decreased attention span.

Stress and anxiety can be exacerbated by the way

the reorganization is managed. Usually, the preliminary negotiations between merging firms are held

in secret, giving rise to negative rumors and feelings of helplessness among employees. When the

content of the talks is disclosed, information usually centers on the legal and corporate financial

matters—not the human concerns preoccupying the

employees. Press reports often highlight the problems associated with the consolidation, and accurate

answers to questions about the merger are difficult

to obtain. In most cases, the details that concern

employees have to be worked out in the months after the sale or merger.

Once the merger begins, the problems become

more complex, and the most important contributor to company discord and stress is the clash in

corporate cultures. Employees and management focus on the differences in the way the two companies operate. Competition develops over whose practices will become the new company policy, and

hostility pits executives against each other.19 The

major airlines include several examples of reorganizations that have been as acrimonious and as stressful as any in other industries,20 as well as mergers

that have been relatively harmonious.

Federal Labor Policy Changes

During the 40 year stewardship of CAB, airline

employees were cushioned from the stressful changes

associated with mergers and other forms of consolidation. CAB routinely conditioned its approval of

mergers and acquisitions upon carrier acceptance

of a standard set of labor protective provisions (LPP).

LPPs addressed the concerns that cause the most

anxiety, such as displacement, dismissal, relocation

allowances, severance pay, and benefits continuation. Also, LPPs established rules for the integration of seniority lists, work rule practices, and, most

significant, wage schedules. While CAB did not have

explicit authority to impose LPPs, courts held that

‘8 ibid.

‘g ibid., p. 41.

~P OTA confidential airline survey.
40

it was within CAB’s purview to impose them as part

of its public interest test.21

Upon assuming CAB’s functions in 1985, DOT

restricted use of LPPs in light of the government’s

more limited role in the airline industry. The current policy requires LPPs only when special circumstances prevent the establishment of fair wages and

equitable working conditions or if a strike arising

from a reorganization would cause a threat to the

entire air transportation system. Since adopting

these criteria, DOT has not required acceptance of

z ! Linda LeGrande, Congressional Research Service, “Airline

Mergers and Labor Protective Provisions,” issue brief 87179, updated

periodically.

LPPs as a condition for merger approval, arguing

that airline employees should be protected from the

adverse effects of mergers through collective bargaining negotiations.22 However, critics point out that

this stringent standard virtually precludes LPPs, and

that labor agreements cannot adequately protect

workers because the contracts may not survive the

merger or acquisition process. Defenders of DOT

policy maintain that LPPs distort the market system, adding costs that could delay or preclude some

reorganizations. They view attempts to require LPPs

as steps toward re-regulation of the industry.

PUBLIC POLICIES AFFECTING AIRLINE OPERATIONS

In addition to deregulation, other public policies

have had profound impacts on airline operations

and safety programs. The President’s decision to fire

the striking air traffic controllers in 1981 and cutbacks in the FAA inspection work force necessitated

by budget cuts in domestic programs represent policy decisions that affected the aviation safety system. Local government decisions restricting airport

traffic and airport development for noise control and

other reasons stem from the conflict between local

goals to provide adequate, safe airport service and

to minimize environmental problems.

Air Traffic Controller Strike in 1981

In August 1981, President Reagan fired the 11,345

air traffic controllers who went out on an illegal

strike, illustrating how an executive decision made

for national labor policy reasons can profoundly affect a vital safety system. The impact of the firing

on labor management relations nationwide was profound, setting the tone for widespread reductions

in union wages and benefits in many industries.

However, the firing of the controllers compounded

existing ATC system problems stemming from obsolete equipment and the increases in airline operations at the busiest airports. FAA had not estimated accurately the increase in the demand for

service nor foreseen the impact that the shift to hub

and spoke operations would have on its work force

and system efficiency.

While FAA began rebuilding its work force immediately after the strike, the loss of two-thirds of

its 16,000 controller cadre seriously affected its ability

to handle traffic. The ATC system operated at about

80 percent of the pre-strike traffic level with a work

force of about 9,000. To handle growing airport traffic with a reduced staff, FAA took steps to spread

the work load so that individual controllers would

not be overwhelmed by high volume peaks in traffic. It established a system of slot allocations and

a reservation system to limit GA access to the ATC

system. A system of centralized traffic management,

“flow control,” was implemented to help reduce airborne delays and keep the demand even and within

system capacity. Aircraft separation was increased

from 3 miles to 5 miles in the airport area, and from

5 miles to about 30 miles in en route travel, and

FAA made extensive use of controller overtime.

Some of these actions are still in effect today.

Federal Budget Cutbacks and FAA

Inspection Program

While the airline industry was growing at an unprecedented rate, budget constraints forced government-wide cuts in Federal spending. In 1979, approximately 645 inspectors were assigned to 178 air

carriers. To comply with national budget goals, the

administration cut the inspector work force by 12

percent in 1982 and 1983, a time when the number

of airlines grew over threefold. The inspector cut-
back had a particularly severe impact on routine

safety inspection programs because staffing priority

went to conducting new certification inspections.

Moreover, FAA was particularly vulnerable to staff

cuts, because it lacked staffing standards to justify

the number of inspectors needed, and the number

of FAA inspectors fell from 3.6 per airline in 1979

to 1.4 in 1983.

The agency began to rebuild the inspector work

force in 1984, hiring enough additional inspectors

to offset attrition and to restore the work force to

the 1981 level. Currently, the inspector work force

is above 1981 levels, but is less experienced. Inspector training is of uneven quality, and the cost of

living in major metropolitan areas makes attracting high quality personnel difficult, according to

FAA regional officials.

Environmental Concerns

As air traffic has increased, so has citizen concern

over environmental issues, including those related

to airport development and use. (See chapter 3 for

a discussion of the institutional relationships of airports to local governments.) By far the most contentious environmental issue is the impact of airport noise on residential neighborhoods. Because

the public is very sensitive to noise and increasingly

vocal about its concerns, noise is probably the most

powerful constraint on airport operations and construction of new facilities.

Although the use of quieter jets can reduce the

level of citizen outrage, the issue of airport noise has

a permanent place in the public agenda. Local politicians can attest that the mere mention of increases

in airport noise can excite constituents into protest

action like few other issues. The noise problem is

particularly troublesome for busy, metropolitan airports that gradually have been surrounded by development. Operations at most airports have increased in recent years, and some flight paths have

been changed, magnifying the noise problem substantially for residential neighborhoods.

To reduce their liability for nuisance and damage claims from noise or at the mandate of local government, airport authorities have instituted noise

abatement programs. Among the most effective, but

expensive, approaches is the purchase by the airport of surrounding residential property, as the Los

Angeles Airport has done. Other techniques more

frequently used include restricting aircraft flight

paths (which must be done carefully, with safety concerns in mind), the volume of traffic, or the hours

of operations based on acceptable noise standards.

Some facilities are experimenting with a noise budget, a plan in which the airport is limited to generating a maximum daily decibel total. Airport management can allocate the noise as it sees fit, raising

intergovernmental jurisdictional issues and potentially shifting the noise problem to other communities.

The proliferation of local noise ordinances and

standards also raises equity concerns. Such regulations could restrict airport access to propeller aircraft or those airlines financially able to purchase

quieter jets.

CONCLUSIONS

Currently the airline industry has achieved one

of the key characteristics of an “oligopoly; through

hub control, the power of CRS booking, and codesharing arrangements, a small number of major carriers dominate the market. This fact, which runs

counter to the policy objectives of deregulation, has

associated tradeoffs for public safety policies. First,

the industry climate is likely to be more stable, and

although the drive for profits will continue, the intense pressure to cut costs across-the-board may be

less, Second, large airlines can be expected to have

the resources and management capability to standardize equipment, institute uniform operational procedures and promote policies within their operation

that may enhance safety. When a major absorbs a

regional carrier it sometimes upgrades the smaller

carrier’s policies and procedures. The goal of one

expansion-oriented major airline is to standardize

its regional carriers so that they all follow the same

procedures, use the same training methods and eventually fly the same type aircraft, thereby developing a work force of pilots and mechanics trained and
42

experienced in the same aircraft.23 Finally, having

only one dominant airline at an airport could reduce congestion and stress on the ATC system.

Lacking intense competition for prime takeoff and

landing times, a single carrier has the flexibility to

schedule flights to maximize efficiency rather than

for a competitive position.

However, nothing guarantees that any safety advantages will be realized; furthermore, gains in stability must be balanced against equity considerations

and the goals of public convenience, open entry,

~~ OTA primary research.

and price competition. Unless action is taken to intervene, it is likely that the airline industry will continue to drift toward increased concentration, fewer

new entrants, and less price competition. Factors

contributing to this trend include noise control or

demand management restrictions imposed on the

ATC system and airport use, or by constraints that

make competition difficult for new firms or for existing firms offering new services. OTA concludes

that Federal decisions that impose ATC or other

restrictions for safety reasons may have severe

economic consequences for airlines in financial

straits. Such decisions thus require careful consideration and active public debate.
Chapter 3

Regulatory and

Institutional Framework

Photo credit: Federal Aviation Administration
CONTENTS

How It All Began . . . . . . . . . . . . . . . . . . . . .

Air Mail Service . . . . . . . . . . . . ● . . . . . . .

Early Safety Initiatives . . . . . . . . . . . . . . .

The Beginning of Economic Regulation

An Expanding Federal Role . . . . . . . . . .

Industry Expansion . . . . . . . . . . . . . . . . . .

Responding to Industry Growth . . . . . . .

Airline Deregulation . . . . . . . ....... .

Federal Aviation Safety Structure . . . . . . .

FAA Responsibility . . . . . . . . . . . . . . . . . .

Other Federal Safety Roles . . . . . . . . . . .

FAA Funding . . . . . . . . . . . . . ........ .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . ..,... ● ✎ ✎

✎ ✎ ✎ ✎ ✎ ✎ ✎ ✎ ✎ ✎ ✎ ✎ ✎ ✎ ✎ ✎ ✎ ✎ ✎ ✎ ✎ ✎ ✎ ✎ ✎ ✎ ✎ ✎ ✎ ✎ ✎ ✌✌✎✎✎☛

✎ ✎ ✎ ✎ ✎ ✎ ✎ ✎ ✎ ✎ ✎ ✎ ✎ ✎ ✎ ✎ ✎ ✎ ✎ ✎ ✎ ✎ ✎ ✎ ✎ ✎ ✎ ✎ ✎ ✎ ✎ ✎ ✎ ✎ ✎ ✎ ✎

Organizational Issues—System Safety Management. . . . . . . . . . . . . . . . . . . . . . . . . . . .

FAA Regulatory Program . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..........

The Office of Airworthiness . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Office of Flight Standards . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Regulatory Program Issues . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Adequacy of FAA Minimum Standards. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

The FAA Rulemaking Process . . . . . . . ........ . . . . . . . ........ . . . . . . . . . . . . .

Air Traffic Control Issues . . . . . . . . ........ . . . . . . . . . . . . . . . . . . .......

FAA Technology Development Issues. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Manpower and Training Needs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Airport Issues and Safety. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ........

Local Control of Airports . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Airport Noise.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ....... ...

Land Use Policies and Airport Capacity. . . . . . . . . . . . . . . . . . ., . . . . . . ........ . .

Conclusions and Policy Options ..

Box

3-A.

3-B.

3-C.

Table

A Regulatory Enigma: When is a

When is it an Air Taxi? . . . . . . . .

Overview of the FAA Regulatory

A Case Study: 747-400 Passenger

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Boxes

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45

46

47

47

48

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50

52

52

54

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page

Commuter an Air Carrier and

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50

Program . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56

Exit Doors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57

Table

Page

3-1. Selected FAA Employee Totals, 1978-87. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52
Chapter 3

Regulatory and Institutional Framework

The Federal Aviation Administration (FAA) has

a dual mandate: “. . . to promote safety of flight . . .

in air commerce through standard setting . . .“ and

to encourage and foster the development of air

commerce. 1 The Airline Deregulation Act, passed

in 1978 to encourage industry competition, removed

Federal controls over routes, fares, and new entries,

but left unaltered the FAA’s responsibility for commercial aviation safety. Events of the past decade

have shown that neither Congress nor the executive branch fully comprehended the complexity of

regulating a newly competitive industry. Although

commercial aviation maintains an enviable safety

record, dramatic growth in air travel, major changes

in technology and industry operations and structure, the firing of the air traffic controllers, and Federal budget constraints have left FAA scrambling

to catch up. Consequently, public attention has

again focused sharply on whether FAA has the institutional capability and resources to carry out its

operating, standard setting, rulemaking, and technology development functions effectively and to

‘Public Law 85-726.

guarantee compliance through its inspection

programs.

Before 1978, the relative stability of the commercial airline industry made carrying out FAA’s regulatory activities less contentious. Industry changes

occurred slowly, fewer carriers were competing for

the travel dollar, and the costs of required safety

improvements could be passed quickly to the consumer. Today’s environment is dramatically differ--

ent, forcing FAA to oversee an industry in which

major players come and go, and airlines must expand markets and control labor and other operating costs carefully or go bankrupt. One consequence

is that aircraft manufacturers and airlines scrutinize

critically any changes of safety regulations, especially

those requiring expensive new technology or additional personnel training. Moreover, Federal policies have explicitly discouraged new regulation, unless judged cost-effective, while local government

policies have restrained new airport development.

This chapter provides an overview of the evolution

of Federal aviation safety laws and regulations, describes the current institutional framework, provides

analyses of the FAA safety programs, and the impact of local regulations on airport use and development.

HOW IT ALL BEGAN

The roots of today’s aviation safety programs, including their rough edges, extend back to the early

days of aviation in the mid-1920s. Early commercial uses of aircraft included advertising, aerial photography, crop dusting, and carrying illegal shipments of liquor during Prohibition. Initial efforts to

establish scheduled passenger service were shortlived, as service catered primarily to wealthy east

coast tourists and was expensive relative to the country’s well developed rail and water travel networks.

Air Mail Service

Growth of commercial aviation was greatly stimulated by the establishment of the U.S. Air Mail

Service in the early 1920s, Regulations established

by the Post Office Department required its pilots

to be tested and to have at least 500 hours of flying

experience and set up aircraft inspection and preventive maintenance programs. These early regulatory

requirements improved air mail carrier safety—in

1924, commercial flyers experienced one fatality per

13,500 miles, while the Air Mail Service had one

fatality per 463,000 miles.2

In 1925, Congress enacted the Air Mail Act, authorizing the Post Office Department to transfer air

mail service to private operators. Twelve carriers,

some of which evolved into today’s major airlines,

~Nick A. Komons, Bonfires to Beacons (Washington, DC: U.S. Department of Transportation, Federal Aviation Administration, 1978),

p. 25.

45
46

Photo credit: Smithsonian Institution

An air traffic controller is on duty at the first radioequipped air traffic control tower at the

Cleveland, Ohio airport in 1930.

began air mail operations in 1926 and 1927. These

carriers offered limited passenger service, which was

much less profitable than carrying mail.3 Small independent operators, using Ford and Fokker trimotor airplanes, handled most of the passenger service in the late 1920’s, the forerunners of today’s commuter airlines and air taxis.

Early Safety Initiatives

No Federal safety program existed, prompting a

number of States to pass legislation requiring aircraft licensing and registration. In addition, local

governments of all sizes enacted ordinances regulating flight operations and pilots, creating a patchwork of safety-related requirements and layers of authority. Modern versions of these difficulties are

discussed later in this chapter. Despite strong industry support for Federal legislation, Congress was unable to reach agreement on the scope and substance

of a statute until 1926.4 when the Air Commerce

Act was passed.5 The new law charged the Department of Commerce with both regulatory authority

over commercial aviation and responsibilities aimed

at promoting the fledgling industry. The major pro-

‘Initially, air mail contractors were paid a percentage of postage revenues. In 1926, however, an amendment to the Air Mail Act of 1925

required payment by weight carried.

‘Key issues debated by Congress included whether to separate military and civil aviation activities, what responsibilities should be left

to State and local governments, and how’ to provide Federal support

for airports. Komons, op. cit., footnote 2, pp. 35-65.

5Congressional Record, 69th Cong., 1st sess., May 20, 1926, 9811.

visions of the act authorized the regulation of aircraft and airmen in interstate and foreign commerce;

provided Federal support for charting and lighting

airways, maintaining emergency fields, and making

weather information available to pilots; authorized

aeronautical research and development programs;

and provided for the investigation of aviation accidents. Local governments were left with jurisdiction

over airport control.

Within the Department of Commerce, a new Aeronautics Branch, comprised of existing offices already engaged in aviation activities, was formed to

oversee the implementation of the new law. Nine

district offices of the Regulatory Division of the Aeronautics Branch were established to conduct inspections and checks of aircraft, pilots, mechanics, and

facilities, and share licensing and certification

responsibilities with the Washington, DC office. The

basic allocation of responsibilities survives to this

day, although the Department of Commerce responsibilities now rest with the Department of Transportation (DOT) and its arm, FAA.

The first set of regulations was drafted with substantial input from aircraft manufacturers, air transport operators, and the insurance industry. Compared with current standards, pilot requirements

were minimal; in addition to written and flight tests,

transport pilots were required to have 100 hours of

solo flight experience, while industrial pilots needed

only 50 hours.

Current procedures for certifying aircraft and engines also originated under these early regulatory

programs. Aircraft manufacturers were required to

comply with minimum engineering standards issued

by the Department of Commerce in 1927, and one

aircraft of each type was subject to flight testing to

obtain an airworthiness certificate for the type.

The Aeronautics Branch also collected and analyzed data from aircraft inspection reports, pilot

records, and accident investigations. These data

were made accessible to the insurance industry, allowing the development of actuarial statistics. A direct consequence of this step was a significant reduction in insurance rates for many carriers.

However, the Department of Commerce, cognizant

of its role to promote the aviation industry, was

reluctant to make public disclosures about the results of individual accident investigations, despite
47

a provision in the 1926 act directing it to do so.

Eventually, in 1934, the Air Commerce Act was

amended, giving the Secretary of Commerce extensive powers to investigate accidents, including a

mandate to issue public reports of its findings.6

This congressional policy decision put safety considerations ahead of protecting the industry’s image.

As additional regulations to improve safety were

implemented, accidents involving passenger carriers

and private aircraft decreased significantly; between

1930 and 1932, the fatality rate per 100 million

passenger-miles declined by 50 percent.7 Updated

regulations established more stringent requirements

for pilots flying aircraft in scheduled interstate passenger service, including flight time limitations.8

Other requirements specified the composition of

flight crews, established standards for flight schools,

improved takeoff and landing procedures, set minimum flight altitudes and weather restrictions, and

required multi-engine aircraft to be capable of flying with one inoperative engine. In addition, certification of carriers providing scheduled passenger

service in interstate commerce commenced in 1930.

Although financial data were not examined by the

Department of Commerce, standards for key personnel, the ground organization of a carrier, maintenance procedures, and aircraft equipment and instruments had to be met.9

The Beginning of Economic

Regulation

During the 1930s, industry expansion and the development of aircraft and communication technologies required continuous improvements of regulations, airways, and airports. However, budget

constraints prevented the Department of Commerce

6R.E.G. Davies, Air/ines of the Unired States Since 1914 (Washington, DC: Smithsonian Institution Press, 1972), p. 201.

‘Komons, op. cit., footnote 2, p. 124.

~Pilots were restricted to flying 100 hours per month, 1,000 hOUrS

during any 12-month period, 30 hours for any 7day period, and 8 hours

for any 24-hour period; a 24-hour rest period was also required for every

7-day period. These requirements, established in 1934, and virtually

the same today, upgraded earlier restrictions which limited pilots to

110 hours of flight time per month. In addition, a waiver of the 8-hour

limitation for a 24-hour period could also be granted by the Department of Commerce. The 8-hour waiver rule was ultimately eliminated

following a fatal accident involving a pilot who had exceeded 8 hours

of flight, and pressure from the Air Line Pilots Association. Ibid, pp.

290-292.

91bid, pp. 116-118, and Davies, op. cit., footnote 6, p. 201.

from conducting sufficient inspections and keeping

up with airway development needs. Moreover, a series of fatal accidents in late 1935, 1936, and 1937,

including one in New Mexico that killed a New

Mexico Senator, called into question the adequacy

of existing regulations.10

The Civil Aeronautics Act of 1938 marked the

beginning of economic regulation. It required airlines, with or without mail contracts, to obtain certificates authorizing service on specified routes, if the

routes passed a test of public convenience and necessity. 11

The Act created the Civil Aeronautics Authority (CAA), which was responsible for safety programs and economic regulations, including route certificates, airline tariffs, and air mail rates. Within

CAA, a separate Administrator’s Office, answering directly to the President, was responsible for civil

airways, navigation facilities, and controlling air traffic.12 However, in June 1940, under the Reorganization Act of 1939, CAA was transferred back to

the Department of Commerce and the Civil Aeronautics Board (CAB) was created and made responsible for regulatory and investigatory matters.

An Expanding Federal Role

Federal responsibilities for airway and airport development grew tremendously during World War

II, leading to passage of the Federal Airport Act of

1946, and initiating Federal financial assistance to

States and municipalities. The Federal Government

assumed responsibility for air traffic control (ATC)

at this time. However, the inspector force could not

keep pace with the rapidly increasing numbers of

new airplanes, pilots, and aviation-related facilities.

As early as 1940, CAA had designated certain parts

of the certification process to industry. For example, flight instructors were permitted to certificate

pilots, and a certificated airplane repaired by an approved mechanic could fly for 30 days until it was

l~he fata]ity rate rose from 4.78 per 100 milhon paSs.enger-miles in

1935 to 10.1 per 100 million passenger-miles in 1936. Komons, op. cit.,

footnote 2, p. 295.

“Civil Aeronautics Act of 1938, Public Law 75-706.

1~Increasing air traffic between Newark, Cleveland, and Chicago

prompted a group of airlines to establish an air traffic control system

in 1934. By 1936, however, the Department of Commerce assumed

control of the system and issued new regulations for instrument flight.

Komons, op. cit., footnote 2, p. 312.
48

checked by an available CAA inspector. After the

war, CAA limited its aircraft certification and inspection role to planes, engines, and propellers; manufacturers became responsible for ensuring that

other aircraft parts met CAA standards.13 

Decentralized Management.–Regulatory and

organizational changes also took place during and

after the war. Regional offices of CAA, reduced in

number to seven in 1938, became more autonomous

in 1945. Regional officials became directly responsible for operations in their regions, although technical standards and policies were still developed in

Washington, DC. Except for a brief return to more

centralized management in the late 1950s, regional

autonomy within FAA has persisted to this day,

slowing communications between and among headquarters and the regions and intensifying inequities

in regulatory applications.

Updating Regulations. –Fatal crashes in the late

1940s and early 1950s prompted revised standards

setting minimum acceptable performance requirements, designed to ensure continued safe flight and

landing in the event of failure of key aircraft components. These standards also distinguished small

and large airplanes based on existing airplane and

powerplant design considerations; small airplanes

were those with a maximum certificated takeoff

weight of 12,500 pounds or less, while airplanes

above 12,500 pounds were defined as large.14 This

distinction is still applied by FAA today, despite significant changes in aircraft design.

Industry Expansion

Beginning of Air Taxi Service.–Surplus war

transport airplanes and a new supply of pilots led

to the development of the nonscheduled operator

or air taxi. Exempt from economic regulation by the

Civil Aeronautics Act of 1938, these operators transported persons or property over short distances in

small airplanes, often to locations not serviced by

the certificated airlines. CAA, at the time sympathetic to private and small operators, applied less

stringent safety regulations to air taxis. ’s In 1952,

13 h~ R M Wi]~O~, Turbulence Alofk The civil Aeronautics Jo

Administration Amid Wars and Rumors of Wars, 1938-1953 (Washington, DC: U.S. Department of Transportation, Federal Aviation

Administration, 1979), P. 152.

141b1d ~. 261; and 43 Federal Register 46734 (Oct. 10, 1978).

15wi]~on, op. cit., fOOtnOte 13, P. 161”

exemption from economic regulation became permanent, even for carriers using small aircraft to provide scheduled service.’s

Certificated Airlines.–The decade following

World War II witnessed enormous industry growth.

Pressurized aircraft traveling at greater speeds and

carrying more passengers were introduced.17 In

addition to scheduled passenger service, air freight

operations expanded when CAB granted temporary

certificates of public convenience and necessity to

four all-cargo airlines in 1949.18 Certification and

operating rules for commercial operators—those

offering contract air service for compensation or

hire–were also adopted in 1949.19

Responding to Industry Growth

However, despite continuing increases in air traffic

and the need for better airports to accommodate

larger and faster aircraft, Federal support for ATC

facilities, airport development, and airway modernization was insufficient. CAA, faced with budget

reductions in the early 1950s, was forced to abandon control towers in 18 small cities and numerous communications facilities, postpone jet development and navigation improvements, and curtail

research efforts. The Federal airport development

program, championed by cities and smaller municipalities, was embroiled in controversy. In addition,

the number of CAA regional offices was reduced

from 7 to 4, 13 safety inspection field offices were

eliminated, and the industry designee program was

expanded.

The impending introduction of jet aircraft and a

1956 midair collision over the Grand Canyon involving a DC-7 and a Super Constellation helped

promote congressional authorization of increased

levels of safety-related research and more Federal

inspectors. In 1958, Congress passed the Federal

Aviation Act establishing a new aviation organization, the Federal Aviation Agency .20 Assuming

16The Civil Aeronautics hard adopted 14 CFR 298, designating an

exempt class of small air carriers known as “air taxis. ” llInitially, Lockheed produced the Constellation which carried 60

passengers and was 70 mph faster than the DC-4. To compete with

Lockheed, Douglas developed the DC-6. Subsequently, upgraded versions of each aircraft-the DC-7 and the Super Constellation—were

introduced. Davies, op. cit., footnote 6, p. 289. IsThe four carriers were Air News, Flying Tigers, SW and ‘“s”

Airlines. See Nawal K. Taneja, The Commercial Airline Industry (Lexington, MA: Lexington Books, D.C. Heath and Co., 1976), p. 6.

1944 F&era] Register 66324 (Nov. 19, 1979).

Zopublic Law 85-726, Aug. 23, 1958, 72 stat. 731.
49

many of the duties and functions of CAA and CAB,

the Agency was made responsible for fostering air

commerce, regulating safety, all future ATC and

navigation systems, and airspace allocation and policy. CAB was continued as a separate agency responsible for economic regulation and accident investigations. 21

The safety provisions of the 1958 act, restating

earlier aviation statutes, empowers the Agency to

promote flight safety of civil aircraft in air commerce

by prescribing:22

• minimum standards for the design, materials,

workmanship, construction, and performance

of aircraft, aircraft engines, propellers, and appliances;

• reasonable rules and regulations and minimum

standards for inspections, servicing, and overhauls of aircraft, aircraft engines, propellers, and

appliances, including equipment and facilities

used for such activities. The Agency was also

authorized to specify the timing and manner

of inspections, servicing, and overhauls and to

allow qualified private persons to conduct examinations and make reports in lieu of Agency

officers and employees;

• reasonable rules and regulations governing the

reserve supply of aircraft, aircraft engines,

propellers, appliances, and aircraft fuel and oil,

including fuel and oil supplies carried in flight;

. reasonable rules and regulations for maximum

hours or periods of service of airmen and other

employees of air carriers; and

● other reasonable rules, regulations, or minimum

standards governing other practices, methods,

and procedures necessary to provide adequately

for national security and safety of air commerce.

In addition, the act explicitly provides for certification of airmen, aircraft, air carriers, air navigation

‘

iHowever, the Federal Aviation Administration Administrator was

authorized to play an appropriate role in accident investigations. In

practice, the Federal Aviation Administration routinely checked into

accidents for rule violations, equipment failures, and pilot errors. Moreover, the Civil Aeronautics Board delegated the responsibility to investigate nonfatal accidents involving fixed-wing aircraft weighing less

than 12,500 pounds to the Federal Aviation Administration. Stuart

I. Rochester, Takeoff at Mid-Centry: Federal Aviation Policy in the

Emnhower Years, 1953-1961 (Washington, DC: U.S. Department of

Transportation, Federal Aviation Administration, 19?6), p. 234.

‘:49 U.S.C. 1421(a).

facilities, flying schools, maintenance and repair facilities, and airports.23

In the years following creation of the Agency, Federal safety regulations governing training and equipment were strengthened despite intense opposition

from industry organizations. The number of staff

members also grew in the early 1960s, and inspection activities were stepped up, including en route

pilot checks and reviews of carrier maintenance

operations and organizations.24 

In 1966, the Federal Aviation Agency became the

Federal Aviation Administration, when it was transferred to the newly formed Department of Transportation (DOT) .25 The National Transportation

Safety Board (NTSB) was also established to determine and report the cause of transportation accidents and conduct special studies related to safety

and accident prevention; accident investigation

responsibilities of CAB were moved to NTSB.

Renewed support for improvements to airports,

ATC, and navigation systems was also provided by

the Airport and Airway Development Act of 1970.

The act established the Airport and Airway Trust

Fund, financed in part by taxes imposed on airline

tickets and aviation fuel, and was reauthorized in

1987. 26

Recognizing that existing industry descriptors,

such as trunks, locals, and commuters (see box 3-

A), were no longer appropriate, CAB redesignated

scheduled passenger airlines into the following

groups based on annual revenues:

●

●

●

●

major airlines (above $1 billion);

national airlines ($75 million to $1 billion);

large regional airlines ($10 million to $75 million); and

medium regional airlines (up to $10 million). 27

~]See 49 U.S.C. 1430, 1422-1424, 1426, 1427, and 1432. Procedures

for amending, suspending, or revoking certifications are contained in

49 U.S.C. 1429.

~+Federal Aviation Administration staff grew’ from 30,000 in 1959

to 40,000 in 1961. Rochester, op. cit., footnote 21, p. 295.

~5U.S. Department of Transportation Act, Public Law 89-670, 49

U.S.C. 1651.

‘GFor additional information on implementation problems associated

with the Trust Fund, see J. Glen Moore and Patricia Humphlett, Congressional Research Service, “Aviation Safety: Policy and O\’crsight,”

Report #86-69SPR, May 1986.

~;U. S. Department of Transportation, Federal Aviation Administration, FAA Handbook of Statistical Information, Calendar Year 1986

(Washington, DC: 1987), P. 11~.
50

Airline Deregulation

Prompted by widespread dissatisfaction with CAB

policies and the belief that increased competition

would enhance passenger service and reduce commercial airline fares, Congress enacted the Airline

Deregulation Act of 1978. 28 Specifically, the act

phased out over a 6-year period CAB control over

2EpubliC L.W 95.504, 92 Stat. 1703. It was thought that fares would

drop based on the record of intrastate airlines where fares were 50-70

percent of the Civil Aeronautics Board-regulated fares over the same

distance. In addition, the Civil Aeronautics Board had already reduced

restrictions on fare competition in 1976 and 1977 and allowed more

airlines to operate in many city-pair markets. Robert M. Hardaway,

“Transportation Deregulation (1976- 1984): Turning the Tide,” Transportation Law journal, vol. 14, No. 1, 1985, p. 136.

carrier entry and exit, routes, and fares. In 1984,

the remaining functions of CAB were transferred

to DOT. These functions include performing carrier fitness evaluations and issuing operating certificates, collecting and disseminating financial data on

carriers, and providing consumer protection against

unfair and deceptive practices.29

During the 60-year history of Federal oversight,

Federal regulatory and safety surveillance functions

have been frequently reorganized and redefined.

Moreover, public concerns about how FAA carries

out its basic functions have remained remarkably

29Civil Aeronautics Board Sunset Act of 1984, Public Law 98-443,

Oct. 4, 1984, 98 Stat. 1703.
51

constant despite a steadily improving aviation safety

record. OTA’s brief historical summary demonstrates that:

● Specifically authorized by legislation after

lengthy debate in the 1950s, industry participation in regulatory activities has a long history, Responsible Federal aviation agencies consistently have designated part of the certification

and inspection processes to the private sector,

specifically certification of pilots, aircraft parts,

and aircraft repair. This reliance on private industry is heaviest when national budget constraints lead to shortages of Federal inspectors

and technical expertise.

● From the initial 1926 legislation to the 1978 Depublic from lack of suitable certification procedures

and standards while FAA developed permanent rules.

Economic Fitness and Reporting

Federal economic regulatory provisions and traffic

and financial reporting requirements for air carriers

also depend on aircraft size: 14 CFR 217 and 241 govern operations of aircraft with maximum capacity

greater than 60 passengers, and 14 CFR 298 covers

smaller aircraft. While all airlines certificated under

Section 401 must meet certain economic fitness requirements, those that operate small aircraft (60 seats

or fewer) have greatly reduced data reporting requirements. In 1952, Part 298 established a class of small

air carriers exempt from economic regulation called

‘(air taxi operators.” CAB designated as “commuters”

those air taxi operators that offered scheduled passenger service. While commuters must meet the same

safety standards as small certificated air carriers, they

have fewer traffic and financial data reporting requirements than the certificated airlines. Other air taxi

operators report no data under Part 298.

nonregulatory Differences

Air traffic controllers use yet another set of terms

for classifying airlines. In compiling statistics on the

users of air traffic control (ATC) services, controllers

categorize aircraft as air carriers (commercial aircraft

larger than 60 seats), air taxis (all other commercial

users), military, or general aviation (all other aircraft).

Commuters are not differentiated in ATC traffic statistics. Since many air taxis operate small single en-

●

●

regulation Act, Congress has charged Federal

agencies with the dual responsibilities of maintaining aviation safety and promoting the industry which history shows are not always compatible. Furthermore, except for a 2-year period

from 1938 to 1940, Federal regulatory and enforcement functions have been combined in one

agency.

Federal aviation regulatory enforcement activities have always been decentralized with regional and district offices having considerable

autonomy and independence from Washington

headquarters.

More stringent safety standards usually follow

a widely publicized airline accident and vocal

public and congressional concern, rather than

gine aircraft, controllers often count them as general

aviation aircraft unless otherwise identified by a flight

plan or aircraft livery.

Until 1986, FAA statistics on near midair collisions

grouped aircraft in three categories only: air carrier,

general aviation, and military. Under this grouping,

all commercial aircraft are air carriers, although FAA

now subcategories air carriers as large air carriers,

commuters, and air taxis.

Federal Standards for Commuter Airlinesa

Large airline Small airline

operations. . . . . . . . . . . . . . . . Part 121 Part 135

Airworthiness . . . . . . . . . . . . . Part 25 Part 23

Economic fitness and

reporting ● . . Parts 241 and 217 Part 298

Commuter airlines must Aircraft size

comply with large airline (in passenger seats)b

regulations for:c’ 1-9 10-19 20-30 31-60 61+

Operations . . . . . . . . .J1.... . . X — X-T- T

Airworthinessd . . . . . . . . . . . . . . – X X X

Economic fitness and
52

from FAA initiatives. Recent examples include

legislation enacted in late 1987 of collision

avoidance equipment requirements for commerFEDERAL AVIATION

FAA Responsibility

Since Congress dismantled CAB, FAA has been

the chief regulator of the U.S. airline industry, with

some political and analytic support from other parts

of DOT. The task is formidable. On the one hand,

the agency must stand up to intense pressure from

DOT and industry on proposed regulatory changes,

and, on the other, address constant public and congressional anxieties about safety and convenience.

FAA’s effectiveness has been undercut by budget

constraints affecting personnel and procurement,

equipment obsolescence, inadequate, long-range,

comprehensive planning, and problems with its inspection and rulemaking programs. (Table 3-1 shows

the impacts of budget constraints on personal levels

in critical areas. ) Furthermore, local governments

play major roles in determining airport operations

and development, often conflicting with FAA goals.

Only an agency with strong leadership and singleness of purpose and responsibility could maintain

a steady course under such conflicting pressures.

Although all FAA sections have safety related

activities, responsibility for the largest safety programs is under the purviews of the Associate Administrators for Air Traffic, Aviation Standards, and

Development and Logistics. Also, all nine regional

offices have broad and separate authority, as does

the Mike Monroney Aeronautical Center in Oklahoma City. This splintering of authority has long

been recognized as creating fundamental organizacial aircraft and broadened altitude encoding

transponder requirements for general aviation

aircraft.

SAFETY STRUCTURE

tional problems within FAA and in its relationship

to Congress, DOT, and industry.

●

●

●

Aviation Standards. Headquartered in Washington, Aviation Standards manages field offices

in charge of both airworthiness standards for

aircraft and regulations for all air carrier operations. The Aviation Standards National Field

Office, located in Oklahoma City, has responsibility for a variety of support activities, including management of national safety databases

and conduct of standardization training for designated examiners. Aviation Standards also receives technical support from the FAA Technical Center in Atlantic City, New Jersey, for

regulatory development and for research and

testing related to crashworthiness and fire

safety.

Air Traffic. Through the regions, Air Traffic

is responsible for operation of the 20 Air Route

Traffic Control Centers, 176 Terminal Radar

Approach Control facilities, hundreds of airport towers, the Central Flow Control Facility, plus Flight Service Stations located throughout the United States and Puerto Rico. In

addition, Air Traffic formulates plans and requirements for future ATC operations, and

evaluates and analyzes current ATC operations.

Development and Logistics. Development and

Logistics is in charge of technology development, implementation, and maintenance, and

Table 3-1.–Selected FAA Employee Totals, 1978-87

Occupation 1978 1979 1980 1981 1982 1983 1984 1985 1986 1987

Air traffic controllera . . . . . . . . 16,750 16,853 16,584 6,658 11,416 11,946 11,944 12,245 12,429 12,847

Aviation safety inspector. . . . 1,466 N/A 1,499 1,615 1,423 1,331 1,394 1,475 1,813 1,939

Electronics technician . . . . . . 9,423 9,209 8,871 8,432 8,031 7,633 7,229 6,856 6,600 6,740

%11 p#OrrnanCelevel and developmental controllers @ towers and centers.

bAlr carrier inspectors (approximately 40 percent of the total) were responsible for 145 air carriers, while general aviation inSWCtOrS were responsible for 173 part 135

commuter airllnes, 7,S04 other commercial aircraft operators, and 5,210 aviation schools and repair stations as of Mar. 10, 19SS.

communications, navigational aid, radar, and automation technicians.

SOURCE: Office of Technology Assessment baaed on Federal Aviation Administration data as follows: controller data as of September 19S7; inspector data as of March

19SS; and technician data as of March 1986.
53

Photo credit’ Federal Aviation Administration

FAA air traffic controllers in the control tower during the annual International Experimental Aircraft Association Convention

and Aviation Exhibition handle 400 takeoff and landing operations per hour.

has overall responsibility for the National Air- ●

space System (NAS) Plan. Offices within Development and Logistics include Automation

Service, which is in charge of upgrading the

ATC system and implementing the Advanced

Automation System. Program Engineering

Service directs other NAS Plan programs, and

Systems Engineering Service handles system ●

engineering for the NAS Plan, advanced systems and concepts, and development of the

NAS Performance Analysis Capability for system-wide airspace management. Systems Maintenance Service directs maintenance of the

NAS. The FAA Technical Center performs

engineering and testing for NAS Plan developments, in support of Development and Logistics.

Within FAA, two additional groups have explicit

safety responsibilities.

Aviation Safety. Reporting directly to the FAA

Administrator, Aviation Safety coordinates accident investigations, safety analyses, and special studies. Aviation Safety monitors safety

activities of FAA programs, but does not function effectively as support to the operations of

these programs.

Mike Monroney Aeronautical Center. Located

in Oklahoma City, the Center houses the FAA

Academy, the Civil Aeromedical Institute

(CAMI), the Aviation Standards National Field

Office, and the Airway Facilities National Field

Support Center. The Academy is the principal

training facility for air traffic controllers. The

Aviation Standards Training Branch at the

Academy trains flight standards and airworthiness inspectors, flight inspectors, and other personnel who work in Aviation Safety. CAMI researchers focus on improving selection and
54

training for air traffic controllers, medically

related aspects of aviation, including controllers’

performance in the field, and physiological

studies of pilot performance.

Other Federal Safety Roles

Other DOT offices oversee economic regulatory

activities previously performed by CAB.

The Office of the Secretary of Transportation

(OST) issues certificates of public convenience

and necessity required for all new carriers. OST

also convenes government/industry meetings

when necessary to handle scheduling peaks and

delays.

The Office of Aviation Operations and Aviation Enforcement and Proceedings in the General Counsel’s Office performs fitness tests that

examine a new carrier’s management capability, financial posture, and regulatory compliance

record.

The Office of Aviation Information Management in the Research and Special Programs

Administration collects economic information

from major, national, regional, and commuter

airlines as required especially under 14 CFR 241

and 14 CFR 298.

The National Transportation Safety Board.–

Although not a regulatory agency, NTSB is an important institutional part of the safety structure. Created in 1966 as an arm of DOT, it became an independent executive branch agency in 1975. In

addition to investigating commercial transport accidents, NTSB conducts special safety studies and

issues recommendations that often call for rule revisions or for new Federal regulations and procedures to correct safety problems. FAA conducts its

own review of accidents and is not bound to accept

NTSB suggestions for regulatory changes.

FAA Funding

Federal Government funding for aviation-related

programs comes from two sources: the Airport and

Airway Trust Fund and from general tax revenues.

The trust fund is financed by excise taxes on the

aviation industry and its users, including an 8 percent ticket tax on commercial air passenger transportation within the United States. In addition, the

unused portion of the trust fund accumulates interest credit payments from the Treasury. Currently,

the largest contributor to the trust fund is the ticket

tax, which accounted for 69 percent of the trust fund

in 1985, followed by interest payments. Aviation

excise taxes are deposited in the general find of the

Treasury. Although trust funds accounted for about

70 percent of FAA’s total budget in fiscal year 1985,

FAA consistently spends less out of the trust fund

than is taken in from excise taxes and interest payments on the balance in the trust fund. Consequently money accumulates in the Treasury, where,

according to current Federal accounting standards,

it can be counted against the Federal deficit. 30

Critics of this policy believe the full resources of the

fund should be available to FAA for operation and

research and development rather than used as a tool

to reduce the Federal deficit figures.

Organizational Issues—System

Safety Management

Notable in this brief description of FAA safety

offices is the absence of a strong, internal system

safety management advocate. A comprehensive approach to system safety could be described as:

The application of engineering and management

principles, criteria, and techniques to optimize safety

within the constraints of operational effectiveness,

time and cost throughout all phases of the system

life cycle.31

Basic system safety management principles are

applicable to commercial aviation and to the National Airspace System. A comprehensive system

safety management program for FAA would apply

to all aspects of planning, data collection and analysis, engineering, and operations. For example, the

economic health and management stability of an

airline strongly influence its ability and willingness

to bear the cost of such safety activities as recurrent cockpit resource management and weather

training for pilots, internal safety audits, and stand3W. S. Congress, General Accounting Office, Aviation Funding:

Options Available for Reducing the Aviation Trust Fund Balance,

GAO/RCED-86-124BR (Washington, DC: U.S. Government Printing Office, May 1986).

‘*U.S. Department of Defense, Military Standard: System Safety

Program Requirements, MIL-STD-882B (Washington, DC: Mar. 30,

1987).
55

ardizing equipment and procedures. Yet while different offices within FAA have recognized the importance of all these factors, the agency has not

systematized procedures to incorporate them in all

areas of its oversight activities. Human error, the

leading cause of commercial aviation accidents, also

receives little FAA attention (see chapter 6). These

shortcomings speak to a need for coherent integrated

safety management at FAA, beyond the development and enforcement of individual regulations and

specific programs targeted at isolated problems.

In the absence of FAA system safety capability,

this function is partially performed by groups such

as Congress and airline labor unions, especially on

issues where powerful interest groups differ vehemently (such as altitude encoding transponders).

However, effective safety management is highly technical and requires continual close, objective attention to system-wide needs. These are beyond the

capability of such groups.

System safety principles are also applicable to the

NAS Plan, throughout all phases of its evolution

and development of its elements, such as ATC technologies. NAS Plan programs often encompass some

elements of system safety analysis. For example, the

Traffic Alert/Collision Avoidance System (TCAS)

program includes modeling and analysis of the effects of TCAS-induced maneuvers on air traffic, and

other efforts to try to identify hazards in the use

of TCAS before it is fully implemented. Procedural

changes in the terminal area are evaluated through

“worst case” scenarios, operational judgment of experienced controllers, and other means, in an attempt to prevent accidents. These efforts are commendable, but maintaining or improving air safety

as traffic levels increase will require a more systematic and broader approach to safety management.

FAA’s Office of Aviation Safety is developing system safety standards for FAA procurements based

on military system safety standards. This is a good

first step, but commitment will be needed to incorporate the principles fully into FAA’s rigid technology development process, and, beyond that, into

the entire life cycles of NAS.

The ATC system and supporting technologies

warrant immediate special attention from a system

safety perspective. The ATC system is currently under severe pressure to extend its operations to the

limits of safe practice to meet the demand for service at busy hub airports. Furthermore, while the

need to modernize ATC facilities is widely recognized, FAA’s current plans include advanced automation features that are difficult to justify on the

basis of efficiency and raise important human-factor

questions (see chapter 7). Rigorous system safety

management, both for the near term and the longer

term, would help maintain the excellent accident

record of the ATC system, as FAA rises to the challenge of managing higher traffic levels. Resources

are required for near-term ATC needs, such as increasing personnel levels and upgrading the computers in Terminal Radar Approach Control facilities. These are needed to accommodate increases

in traffic and transponder users. Attention to formulating a better system safety groundwork for the

more advanced parts of the system is also important.

Internal Communications

An additional and related problem is internal

FAA communication paths. As shown in figure 3-

1, vertical lines of communication exist between the

Administrator and the programs under the purview

of the Associate Administrators and with the nine

regional offices. However, the chart also illustrates

that 22 separate groups report to the Administrator and that no formal lines of communication are

apparent among the operating programs and within

program divisions. Moreover, even when communication lines exist, they are often ineffective because

of timing and rigidity of responsibilities. For example, under the Associate Administrator for Development and Logistics, individual program managers

in two offices are responsible for meeting milestones

in the development and implementation of NAS

subsystems. A third office is responsible for defining requirements and ensuring that individual subsystems combine effectively to form an overall system. Because many of the programs in the NAS Plan

are already well underway by the time requirements

are defined and validated, program managers have

difficulty refocusing away from milestones and responding efficiently to inputs from other groups.

Within the last 15 years, FAA has had seven administrators, serving an average of 2 years. Although

this length of term is not unusual for Administration appointees, this high rate of turnover highlights

a central concern about FAA’s capability to per-

&j.&jo - 88 - 3 : QL 3
form its safety mission–the requirement for longrange planning and policy commitment. Since many

of FAA’s responsibilities involve long-range programs, such as the modernization of equipment and

facilities, the absence of consistent leadership is severely felt.

FAA REGULATORY PROGRAM (see box 3-B)

Although largely unnoticed by the traveling public, Federal safety regulations, administered by FAA,

establish the basic safety structure for U.S. aviation.

Regulatory and oversight functions are primarily

housed under the Associate Administrator for Aviation Standards, and activities of two of its offices

are critical during times of major industry change.

The Office of Airworthiness

The Office of Airworthiness has two prime functions: to establish minimum standards for the design and manufacture of all U.S. aircraft and to certify that all aircraft meet these standards prior to

introduction into service. Airworthiness standards

prescribe explicit flight, structural, design and construction, powerplant, and equipment requirements.

The office issues “type”32 certificates to prototype

aircraft built in conformance to airworthiness standards after successful testing. Manufacturers try to

ensure that individual aircraft conform to the type

to obtain FAA airworthiness certification. If major

changes are made in an aircraft design, a new type

certificate is required. However, if less extensive

changes are made, FAA amends a type certificate

and issues a supplemental one. As pilots must have

additional and expensive training to operate a new

type of aircraft, manufacturers and airlines prefer

continuous supplemental certificates and pilot type

ratings.

Four FAA regional offices have certification authority for aircraft and certain systems:

● Central Region (Kansas City) certificates general aviation aircraft.

● New England Region (Boston) certificates engine and propulsion systems.

● Northwest Mountain Region (Seattle) certificates large commercial aircraft.

● Southwest Region (Fort Worth) certificates

helicopters.

This decentralized management lends itself to internal FAA disagreements over regulatory actions

and sometimes outright contradictions (see box

3-C for details).

Office of Flight Standards

Commercial aircraft are spot checked by Flight

Standards inspectors to ensure they comply with

Federal Aviation Regulations. This office certifies

that new air carriers meet Federal standards and approves flight procedures, determines some equipment regulations, and is responsible for seeing that

inspectors conduct routine safety inspections.

1 214 CFR I. I Uan. I, 1987).
57

FAA inspections are divided into three functional The principal functional area inspectors are assisted

categories: by inspectors from one of the 90 FAA district offices

● Operations, including minimum equipment

lists, pilot certification and performance, flight

crew training, and in-flight recordkeeping.

● Maintenance, including maintenance personnel training policies and procedures for overhaul, inspection, and equipment checks.

● Avionics, specializing in aviation-related electronic components.

Usually, each airline is assigned a principal inspector for each of the three categories of inspections.

within whose boundaries the airline operates. In

addition to certificating new airlines and performing routine inspections, FAA principal inspectors

are responsible for investigation and enforcement

duties. 33

‘1.J. S. Congress, General Accounting Office, Report on Aviation

Safety: Needed Improvements in FAA’s Airline Inspection Program

are Underway, GAO/RCED 87-62 (Washington, DC: May 1987), p. 12.
58

Regulatory Program Issues

In the years just prior to deregulation, standards

and procedures followed by major U.S. airlines often

exceeded minimum Federal requirements. However,

starting in 1978, economic forces exerted great pressure on redundancies in industry safety programs,

eliminating some and intensifying the importance

of strong Federal enforcement programs. At the

same time, FAA’s capability to monitor the industry was swamped by problems, which were in part

products of executive branch policies and governmental budget constraints, and which were independent of deregulation, although deregulation magnified their impact.

Investigations conducted since 1983 by FAA itself, the General Accounting Office (GAO), and

NTSB cited weaknesses in the FAA inspection programs. OTA research confirms that severe difficulties persist, although work is underway to standardize procedures and provide for greater flexibility in

personnel assignments.

Criticism of the FAA inspection program generally focuses on three categories: manpower and training, information systems, and management control.

Manpower problems became acute during the early

years of deregulation when Federal budget constraints required cuts in the inspector work force.

At the end of fiscal year 1978, FAA had 1,580 Flight

Standards field office inspector positions authorized,

and actual employment was 1,466. By fiscal year

1981, the authorization had risen to 1,748, and 1,615

inspectors were “on board” on September 30, 1981.

Three years of deep budget cuts reduced the authorization by 18 percent to 1,440 inspectors by the end

of fiscal year 1984. (Actual employment on September 30, 1983, was 1,331 inspectors.) At the end of

fiscal year 1978, there were 556 “air carrier” inspectors employed (605 authorized) which increased to

623 (674 authorized) by the end of fiscal year 1981,

and fell to 507 (569 authorized ) by the end of fiscal

year 1983. The planned end of fiscal year 1984 authorization was 508, later increased to 674 (the 1981

high). Thus, while the number of airlines was rapidly rising in the years following deregulation (the

number of commercial operators roughly doubled

between 1979 and 1983), the number of air carrier

field inspectors in FAA was rapidly declining. Inspectors were shifted from routine operations and

maintenance inspections to airline certifications.

FAA’s end-of-year goal for fiscal year 1988 is 2,088

field office inspectors, and FAA plans to add about

285 inspectors in each of fiscal years 1989, 1990, and

1991.34

Moreover, even if numbers of newly hired inspectors reach adequate levels, FAA inspector training

programs cannot keep up with new industry procedures and equipment, such as contract maintenance

work and new cockpit technologies. Training is most

problematic in areas of recent technological development, such as advanced composite materials used

by aircraft manufacturers, new navigational systems,

and other computerized systems.35 As aircraft and

technologies become more complex and sophisticated, training for inspectors will become even more

critical.

Furthermore, FAA managers have long lacked

current and reliable information on allocation of

inspectors and inspection records, leading to inconsistencies among FAA district offices, and inadequate followup to inspection activities. Shortages

of computerized equipment and lack of high quality core training at the Oklahoma City Academy

exacerbate information difficulties.

Traditionally, FAA has delegated broad authority to regional and district offices concerning the frequency and scope of inspections. FAA regional

offices stoutly reaffirm the importance of meeting

regional needs at the regional level, leaving general

policy guidance to Washington. However, FAA

headquarters has never effectively centralized management control to permit evaluating regional and

district inspection activities, to ensure uniformity

in policies and procedures, and analyze inspection

findings on a national scope. Wide variations in the

number and kind of inspections performed from region to region identified by GAO in 1985, still persisted according to OTA’s research.36

J+Anthony J. Br~erick, assaiate administrator, Aviation Standards, Federal Aviation Administration, personal communication, Mar.

31, 1988.

‘5General Accounting Office, op. cit., footnote 33, p. 50.

‘U.S. Congress, General Accounting Office, Compilation and

Analysis of the Federal Aviation Administration’s Inspection of a SampIe of commercial Air Carriers, RCED-85-157 (Washington, DC: Aug.

2, 1985); and OTA primary research.
59

The competence and professionalism in the manufacturing and operating industries ensure airworthiness of commercial aircraft to current standards,

and past history shows that industry safety standards are almost always high. FAA needs adequate

technical expertise and records to be able to target

the rare cases where standards are not sufficiently

high, as well as knowledge about industry management attitudes and financial stability.

To improve management of its inspection responsibilities over the long term, FAA initiated Project

SAFE, a program to establish staff standards, increase staff levels, improve inspector manuals and

training courses, and establish performance standards for each FAA regional office. Task forces made

up of headquarters and regional staff are revising

and standardizing inspection manuals and training

policies. Needed improvements to training courses

in Oklahoma City and standardizing of regional onthe-job training are planned under Project SAFE,

but are moving at a snail’s pace. Moreover, emphasis

on monitoring individual airline characteristics, such

as compliance records, fleet composition, management changes, and financial stability, would permit

FAA to allocate its inspector resources more effectively.

Adequacy of FAA Minimum Standards

The recent major airline crash in Denver and a

spate of commuter accidents focus attention not only

on inspection programs, but also on the adequacy

of FAA minimum safety standards. Although most

airlines maintain standards above the minimum required by FAA, some safety officials are concerned

that the minimum may not be adequate in some

instances. Because of such concerns, the Department

of Defense has instituted a safety program that frequently uses a higher standard in selecting contract

airlines than the minimum standards required by

FAA.

In response to the 1985 crash of a military chartered DC-8 in Gander, Newfoundland, the Military

Traffic Management Command (MTMC) and the

Air Force Military Airlift Command (MAC) overhauled their inspection program and established an

Army/Air Force Central Safety Office to coordinate standard setting and inspection activities. Enforcement actions against the airlines are the responsibility of a military review board.37 The MTMC/

MAC office conducts inspections, in addition to

FAA’s, of all airlines used for military charters. During the 2 years since the Gander crash, the safety

office has disqualified 13 U.S. airlines and taken

lesser disciplinary actions against 9 others. Poor

maintenance practices and failure to comply with

airworthiness directives are the most frequent problems. Half of the cited airlines were large carriers

operating under Part 121.

By the summer of 1988, the MTMC/MAC safety

program will be supported by a new database. The

Air Carrier Analysis System (ACAS) will compile

and analyze data on airline accidents, incidents,

maintenance and operating problems, and financial

characteristics. The system will alert inspectors to

those circumstances at an airline that warrant personal inspections and provides a useful model for

FAA, which is cooperating with MTMC/MAC.J8

However, ACAS relies upon FAA databases which

are incomplete and are not designed to support

analyses.

The FAA Rulemaking Process

Prior to deregulation, FAA had considerable regulatory autonomy, overseeing an industry in which

profits were protected through the extensive rate and

entry rules of CAB. Over the past decade, vigorous industry economic competition has made rulemaking a distinctly adversarial process. Carriers,

labor groups, aircraft manufacturers, and general

aviation supporters carefully scrutinize every proposed safety regulation and question its efficacy and

impact on costs. Often such activities, in concert

with administrative policies and bureaucratic labyrinths, have effectively blocked safety regulations for

years.

Presidents Ford, Carter, and Reagan each initiated progressively stronger and more centralized programs of regulatory review in response to concerns

about the excessive burdens and inadequate management of Federal regulations. These policies, implemented explicitly through Executive Orders in

1981 and 1985, direct agencies to:

‘

i

James Ott, “Military Avoids U.S. Carriers That Fail Safety Standard,” Aviation Week & Space Technology, Feb. 8, 1988, pp. 99-101.

~gIbid. and Broderick, op. cit., footnote 34.
60

● base their regulatory rulemaking decisions on

benefit-cost analyses,

. submit new regulations for review by the Office of Management and Budget (OMB),39

. refrain from starting work on any significant

new regulation until consulting with OMB, and

● publish in the annual Regulatory Program a status report on each significant regulatory initiative.

While all executive branch agencies have had to revamp their regulatory procedures as a result of these

Executive Orders, FAA has faced a special challenge

because proposed remedies to safety risks often entail expensive technological developments requiring

long lead times.

Moreover, DOT has gone substantially beyond

Executive Order mandates for economic review of

proposed rules for all its modal agencies. Cost-benefit

analyses are required only for identified “major” regulations, but in contrast to some other executive

branch agencies, DOT expanded this requirement

to include “significant” rules, a category that covers nearly all regulations.40

For FAA, the review process now consists of the

following major steps:

● FAA advises the Office of the Secretary of in-

‘~homas Hopkins, “Aviation Safety Rulemaking,” OTA contractor report, August 1987, p. 5.

‘“Ibid, p. 7.

●

●

●

●

tent to start work on a significant regulation.

DOT departments register concerns about the

proceeding or about analysis needed.

A team of FAA staff members develops a new

rule proposal.

A member of FAA’s Office of Aviation Policy,

who also serves on the rule-drafting team, prepares the cost-benefit analysis.

After FAA approval, the regulatory package,

complete with economic analysis, moves to

DOT’s General Counsel Office for a required

departmental review, including Assistant Secretaries for Policy and International Affairs,

Government Affairs, and Budget and Programs.

Prior to public release, the General Counsel

mediates ‘OMB’s review of the regulation and

economic analysis.

In a major review of its regulatory program in

1984, FAA identified over 100 regulations needing

revision. Twenty-six regulations were assigned high

priority status and are currently in various stages

of the process; another 85 form a large backlog. Long

backlogs can lead to “immediate action” regulations

and inspector handbook changes that alter regulations without adequate due process. While FAA

plans a rewriting of Part 121 and 135 regulations,

this major undertaking

sive effort.41

41(jeneral Accounting ‘ceV

AIR TRAFFIC CONTROL ISSUES

In the aftermath of the controller’s strike and con- goal of FAA’s recovery

will require years of intenop. cit., footnote 33, p. 26.

plan was to return to 100

current with its effort to even out traffic flow, FAA

began to rebuild the controller work force by hiring, training, and certifying new controllers at an

accelerated pace. Anticipating a more efficient controller work force as a result of NAS Plan improvements (see chapter 7) and believing that the prestrike work force was overstaffed, the administration established a target work force goal of 14,306,

lower than the pre-strike level. Also, believing that

the pre-strike controllers were more qualified than

necessary, FAA lowered the goal of full performance level controllers to 75 percent from 80 percent.

FAA has succeeded in achieving some of the goals

of its recovery schedule but not all. The primary

percent of pre-strike traffic level, with flow control

in place, by June 1983. This target was met on schedule, but goals to reduce the extensive use of flow

control and to have controllers return to normal

work schedules in every facility still elude the agency.

Also, supervisors still work traffic during peak hours

more and work more overtime hours than before

the strike.

The rebuilding process has been slow and tedious. Because of the special aptitudes required for the

job, a higher than expected washout rate of new

recruits has slowed recovery. Also, retirements, promotions to supervisory jobs, and normal attrition

has cost the controller work force many of its most
61

Photo credit: Federal Aviation Administration

FAA air traffic controllers handle traffic in the Dallas-Fort

Worth Terminal Radar Approach Control

(TRACON) facility.

experienced members, about 500 each year from retirements alone.42 Training capabilities have been

especially hard hit.

The effects of the strike on individual airports varied widely. Some were hardly affected, while others

+zCecilia p~~bl~, ‘lG~OWth of Air Traffic Raises ATC Staffing Issue,”

Aviation Week & Space Technology, Mar. 31, 1986, p. 44.

lost most of their work force. In general, the effect

was greatest where the union was most active—in

Chicago and New York City airports, more than

95 percent of the full performance level controllers

struck and were fired. More remote, less demanding facilities had few strikers. The resulting disparity in the geographical distribution of experienced

controllers remains a very difficult problem for FAA.

Moreover, even at present, differences in living

costs, traffic volume and complexity, and other factors, compound difficulties in filling controller

vacancies in major metropolitan areas such as Los

Angeles, Chicago, New York, and Boston. In mid1986, O’Hare airport had 52 vacancies for full performance level controllers. Special FAA programs

to attract experienced controllers to these busy facilities have had only limited success, and staffing

shortfalls must be met with newly trained recruits.

Therefore, the controller work force at some of the

busiest airports can be among the least experienced

or trained. While FAA has a mandate to increase

the air traffic controller work force to 15,800 by October 1988, the increase in total numbers of controllers will not eliminate these particular problems.

FAA TECHNOLOGY DEVELOPMENT ISSUES

Federal acquisitions of major technical support systems are governed by OMB Circular A-109, which

divides acquisition into four steps:

●

●

●

●

Identification of mission need for a technological system, including some development of cost

and schedule goals.

Identification and exploration of alternative design concepts, followed by demonstration of the

concepts.

Full-scale development and limited production.

Full-scale production.43

However, FAA does not always follow this standard protocol. For example, none of the original 11

major NAS Plan programs adhered to A-109, and

all the programs that have reached key decision

points have skipped steps in the process. Such short-

‘]U.S. Congress, Office of Management and Budget, “Major System

Acquisitions: A Discussion of the Application of OMB Circular No.

A-109,” OF PP Pamphlet No. 1, August 1976.

cuts have led so far to successful deployment of the

Host computer system at Air Route Traffic Control Centers only 6 months behind the original

schedule. Other programs have slipped far behind

schedule and have incurred large cost increases compared to original estimates. Schedule slippage and

cost increases are not unusual for large and complex government development programs. However,

some NAS Plan delays were incurred because the

components as originally conceived could not be

completed without additional engineering work and

adaptation to the rapidly changing air traffic system. None of these were adequately anticipated in

the original plan.

The long-term NAS Plan programs have not met

shorter-term needs of the system—these shorter-term

needs require the capability for anticipating problem areas and rapid development and operational

testing of alternative solutions, in addition to longterm developments.
62

Manpower and Training Needs

Manpower, logistics support, and technical training needs were not fully considered in designing the

NAS development program. As NAS becomes more

fully automated, personnel who maintain NAS

equipment and other highly technical programs will

require sophisticated training. Also, budget constraints have held down appointments for technicians to maintain NAS systems in the field, of significance because many current technicians will be

eligible for retirement soon.44

Because contractor maintenance of NAS equipment is not always of sufficient quality, FAA must

train technicians. Classroom and laboratory training are done at the FAA Academy, which is not

well prepared to meet the needs. The rapid influx

of new, automated NAS systems requires rapid development of new training courses and, over time,

will require radical changes in requirements for training of field personnel. Field technicians who

troubleshoot equipment will be replaced in the future by engineers who monitor system parameters

remotely for signs of trouble. This will call for

broader, more sophisticated training than is now

usually given at the Academy. Capabilities are being developed for more efficient design of training

courses, including job task analysis, computer-based

instruction, and an automated training development

system. Still, the Academy views NAS Plan delays

with relief, because they allow more time for training course development.45 Moreover, instructors’

grades at the Academy (GS-12) are not as high as

those of automation engineers and systems engineers

in the field, and instructors at the Academy are

sometimes snubbed for the higher-grade jobs when

they return to the field.% These conditions are not

conducive to more sophisticated training at the

Academy.

4qMe~ Yoshikami, manager, Airways Facilities Division, Federal

Aviation Administration, personal communication, Aug. 6, 1987. 4jMorrls Fri]oux, su~rintendent, Federal Aviation Administration

Academy, personal communication, Dec. 8, 1987.

46Richard J. McCafihy, training branch manager, Airways Facilities)

Federal Aviation Administration, personal communication, Dec. 14,

1987.

AIRPORT ISSUES AND SAFETY

The Federal role in airport development and management has grown as airports have become increasingly critical links in the Nation’s transportation system. In the early years of U.S. aviation, Congress

held that airports were not a matter of Federal interest and should be developed and managed locally.

Federal responsibility was limited to charting airways, providing lights for night flying, maintaining

emergency fields, and furnishing weather reports.

However, World War II changed this limited perspective, and national defense became a major rationale for Federal participation in airport development. Congress appropriated $500 million from the

general fund for a capital grants program for airport improvements in the Federal Airport Act of

1946. 47 The Federal Aviation Act of 1958 continued the policy of providing support for airport

WU.SC Conwess, Mce of Technology Assessment, Airport System

Development (Washington, DC: U.S. Government Printing Ofllce, August 1984), p. 29.
63

development from the general fund, although Congress was becoming uncomfortable with this type

of direct subsidy with general funds.

In the Airport and Airway Development Act of

1970, Congress institutionalized Federal airport aid,

establishing the Airport and Airway Trust Fund to

modernize ATC and support the Airport Development Aid Program (ADAP). The act levied an airline ticket tax and a GA fuel tax to provide a dedicated source of revenue; it also provided grants

through ADAP to assist airport operators in funding capital projects. In 1982, Congress reauthorized

the Airport and Airways Trust Fund and initiated

a new capital grant for airport improvements. Recognizing State and local noise concerns, the act

earmarked 8 percent of these new funds for noise

abatement projects. In December 1987, Congress

reauthorized the Trust Fund, reaffirming support

for joint Federal/State/local responsibility for

airports.

FAA has always played an important role in the

operational side of airport management. Because it

owns and operates the ATC system, including many

ATC towers, navigational equipment, and landing

aids, it directs the flow of traffic in the local airways

and in and out of commercial airports. In this capacity, FAA has direct control of and responsibility for air traffic safety. Airport improvements that

require installing, moving, or upgrading ATC equipment have to be approved and implemented by

FAA. In addition, safety and operational standards

for airports, established by FAA, must be followed

in projects supported by Federal funds.

Local Control of Airports

Despite an increase in Federal involvement in airport development and operations over the last 20

years, most airports in the United States are locally

owned and operated. More than half of the Nation’s

large and medium commercial airports, and a greater

percentage of small commercial facilities are operated by municipal and county governments.48 A

typical municipally operated airport is city-owned

and run as a department of the city, with policy

direction by the city council or by a separate airport commission or advisory board. Another large

481bid, p. 21.

group of airports are run by multipurpose port

authorities—public corporations that operate a variety of publicly owned transportation facilities such

as harbors, toll roads, and bridges. Also, singlepurpose authorities operate both medium-size airports and large facilities.

Airport Noise

Noise became a major political and environmental

issue in the early 1960s with the widespread introduction of commercial jet aircraft. FAA estimates

that the land areas affected by aviation noise increased about sevenfold between 1960 and 1970.49

Residents living near airports and along flight paths

complain that aircraft noise is annoying—especially

at night—and depreciates the value of their property. Scientific evidence corroborates that high exposure to noise can lead to high stress levels, nervous tension, and inability to concentrate. Although

according to FAA only about 2 percent of the U.S.

population is affected by aircraft noise, the noise issue has affected operations at many major airports

and is a major factor in constraining airport expansion and development.50

Reacting to public outcry, Congress amended the

Federal Aviation Act in 1968, requiring the FAA

Administrator to take regulatory action to control

and abate aircraft noise. To reduce the noise made

by aircraft and engines, FAA established maximum

noise standards for newly manufactured aircraft engines through FAR part 36. Known as stage 3 aircraft, those that meet the quieter standards are expected to replace existing equipment by the year

2000. FAA grant funds are available for noise abatement programs including purchase of equipment to

measure noise, sound proofing nearby buildings, and

even the purchase of contiguous property severely

affected by aircraft noise.

While FAA supports the concept of local noise

abatement programs, it leaves regulating noise to

the airport operators. A Federal noise standard

could expose the Federal Government to liability

for damages if the standards were exceeded. Moreover, restricting air traffic for other than safety reasons conflicts with FAA’s mandate to foster air

4gIbid, p. 21.

‘Ibid.
64

commerce. However, FAA has established guidelines for measuring noise and has suggested methods for determining land uses compatible with various day-night average sound levels. On the other

hand, Executive Order 12371 requires that Federal

agencies such as FAA, consult and cooperate with

local governments in the administration of Federal

assistance and development programs. This review

and approval power provides local and regional governments with leverage to require adoption of noise

standards and to require noise abatement measures

as part of a federally financed airport development

project.

Motivated by political pressure from local residents

and the fear of liability claims, airport operators are

using their authority—although limited—to control

noise. The basic legal ground rules for noise control strategies are that they be nondiscriminatory,

do not unduly burden interstate commerce, and

have the effect of reducing noise. Finally, noise

abatement restrictions must not interfere with safety

or the Federal prerogative to control aircraft in the

navigable airspace.

Local restrictions on aircraft to reduce noise generally fall into three groups. One strategy is to modify flight paths in cooperation with local ATC staff

so that aircraft fly over water, industrial or vacant

land, and avoid densely populated areas. Second,

local airports can limit the number of flights or the

types of aircraft; and third, some airports are experimenting with noise budgets that set a maximum

daily decibel total, which the airport allocates among

carriers.

Undeniably, noise abatement restrictions reduce

airport capacity and can cause delays, sending ripples throughout the air traffic system. Moreover, pilots on tight schedules are tempted to abbreviate

check lists and fly above FAA-approved speeds to

beat nighttime curfews at their destinations. Some

departure and arrival speed and flight path control

requirements may adversely affect safety, and FAA

needs better analytic tools to help identify the impacts on safety and develop countermeasures for the

curfew restrictions. Finally, noise restrictions create

equity issues. Although the courts have struck down

blatantly discriminatory plans, stringent noise restrictions could force carriers to accelerate fleet

replacement.

Land Use Policies and

Airport Capacity

The absence of strong, local land use policy to protect existing airports from encroaching development

limits the capacity potential of the airport system.

Land suitable for airport expansion is either too expensive or unavailable, and hostile neighbors seek

to limit the number of existing flights. Ironically,

the availability of highway access and utilities required by the airport attracts residential development. In rural jurisdictions on the fringes of metropolitan areas, local officials often do not support

land use controls, and airports unprotected by regulations become focal points for development.

Obstacles to Expanded Airport Capacity

Local and regional governments do not find it easy

to gain wide public support for long-range commitments to runway and airport planning and construction. During the next 10 years, construction may

begin on only two major new airports (a replacement for Denver’s Stapleton and a new one at Austin, Texas), and even that modest estimate may not

be achieved. The complexity of any airport project

requires coordination and agreement among Federal, State, local and regional governments on airport siting and specific development and acquisition

plans and projects. To highlight the enormity of land

acquisition, the Dallas-Fort Worth Airport required

the purchase of 18,000 acres and agreements protecting an additional 4,000.

In short, additional airport capacity is years away,

and FAA needs systematic plans to handle safely

projected increases in demand, which may include

demand management where necessary. The alternative is to accept delays as an inevitable accompaniment to an overburdened system.
65

CONCLUSIONS AND

While FAA’s dual responsibilities of providing

aviation safety and fostering air commerce are not

always incompatible, in times of rapid industry

change, they present the agency with unavoidable

conflicts. Congress may wish to identify safety as

FAA’s sole and unique responsibility, especially

for ATC and regulatory programs. Responsibility

for fostering economic development of the industry could be returned to the Secretary of Transportation. Given the current growth of the industry, the competitive industry climate, and the

constraints on FAA personnel levels and technical

expertise, reaffirmation of the primacy of safety could

clarify goals for allocating FAA resources. Industry

promotion functions are compatible with DOT’s

economic and consumer protection functions, and

DOT staff is better-suited to deal with complex economic and political questions of demand management than the highly trained technical personnel

in FAA. Close communication should be maintained so DOT aviation policy makers have the

advantage of FAA’s technical knowledge and safety

expertise.

Many of FAA’s problems identified in this chapter have their roots in the bureaucratic culture and

are characteristic of most Federal agencies. The lack

of agency autonomy over personnel, procurement

processes, and budget decisions and its inability to

adapt quickly to change are not problems unique

to FAA and will exist to some extent regardless of

the organizational structure within the government.

Undeniably, however, FAA’s effectiveness during

the recent past has been undercut by national budget problems that have limited the FAA work force

in numbers (see table 3-1) as well as levels of technical expertise. OTA finds that assisting FAA to

overcome some of these special difficulties is an

important safety priority for Congress to consider.

For example, provision for cost of living adjustments for assignments in major metropolitan areas

could ease transfer of personnel to facilities with

special needs. Mechanisms to speed contracting

procedures for training and other vital procurements could be helpful.

While there is general agreement about the organizational and operational weaknesses of FAA,

proposals for reform range widely. The debate over

POLICY OPTIONS

reshaping the Federal Government’s oversight

bureaucracy centers around these general concepts:

●

●

●

●

Length of the Administrator’s term.

Policymaking relationship between DOT and

FAA.

Status of ATC functions. Proposals include

contracting ATC service to a private provider,

establishing a Federal corporation, and forming a nonprofit, user-owned corporation.

Status of the Aviation Trust Fund. Debate

centers around the unified Federal budget

process.

The frequent turnover of Federal administrators

works against unified decisionmaking and the implementation of comprehensive long-range planning

in every agency, and FAA is no exception. OTA

finds that without stronger leadership, FAA prob.

lems of inadequate long-range planning, interdepartmental coordination, management information, and uneven application of regulations by

regions are bound to continue. Congress may wish

to consider setting a fixed term of up to 5 years

for the FAA Administrator. A seasoned administrator will have a better chance at tackling the bureaucratic problems of procurement and personnel

and budget restrictions.

Allocation of agency resources through the budget process requires close coordination with planning goals to ensure support of priority objectives

and programs. A strong administrator could establish, through reorganization or management directives, greater control over the regional offices to

ensure coordination, consistent policy, and evenhanded application of regulations. Organizational

changes and management incentives could improve

internal communications among operating programs

and within program divisions. To keep up with the

technological and structural changes in the industry, FAA’s rulemaking process needs to be streamlined and safety considerations better integrated into

all levels of analysis. As the industry grows and aircraft technologies become more complex and sophisticated, FAA’s need for more and better trained inspectors and technical personnel will become even

more critical. Equally important is the need for hiring and adequate training of personnel responsible

for maintaining the technology of NAS.
66

To provide accountability for the fixed-term administrator, Congress may wish to require him or

her to develop a rolling 5-year agency develop.

ment plan and to report annually on its status.

Based on clearly stated goals and objectives for

personnel, technology, and regulations, such a

plan could provide Congress with a tool for assessing the agency’s progress and a picture of its longrange direction.

Noise issues will continue to constrain airport

operations and development. ATC bears the brunt

of the safety implications of such local regulations

and the impact of increased demand on major hub

airports. Advocates of an independent ATC system reason that this large, highly technical operation could be more efficiently managed if separate

from the Federal regulatory program. OTA finds

that the ATC function is inextricably linked with

aviation safety and is a central component of an

integrated FAA safety system. While Congress has

demonstrated its reluctance to alter the current policies pertaining to the use of the Aviation Trust

Fund, short-term improvements to ATC to address

capacity problems and the need for enhanced FAA

technical expertise are immediate needs that could

be addressed by resources from the fund. Demonstration by FAA of a plan to use funds specifically

for such purposes could help to convince Congress

to authorize them. However, other ongoing FAA

activities fall under the Federal responsibility for

safety in interstate commerce and are appropriately

supported by the General Fund. Moreover, FAA

could further enhance its technical expertise by better use of existing Federal resources at the National

Aeronautics and Space Administration (NASA)

and NTSB.

Furthermore, OTA concludes that FAA needs

a strong, comprehensive, internal safety management system to support planning and ensure that

the full resources of the agency coordinate and

focus on the most important safety issues. ATC

improvements, regulatory and enforcement programs, and NAS Plan programs in particular ware

rant attention from a system safety perspective.

Currently, in the absence of system safety management at FAA, backed by strong technical expertise,

safety issues come to Congress and other groups,

ill-suited to perform safety management functions.

Although many in the aviation community find

DOT intrusive and overly political, DOT represents

FAA’s interests in the cabinet—especially important

during budget formulation—and often provides a

balanced policy viewpoint on some issues in contrast to FAA’s technical perspective. Moreover,

OTA finds that removing FAA from DOT does not

by itself address the principal frustrations currently

voiced. The sources of these frustrations are twofold: overall Administration policy and internal

FAA management problems. OTA concludes that

FAA independent of DOT would still be subject

to Administration policies, just as NASA is. Furthermore, internal problems must be resolved by

and within FAA proper.
Safety Measure

Chapter 4

ments

and Data Resources

Photo credit: Federal Aviation Administration

Air Safety databases are maintained at FAA’s computer center in Oklahoma.
CONTENTS

Measuring Transportation Safety. . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Safety Factors. . . . .. . . . . . . . . . . . . . . . . . . ....... ....

Exposure Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ......

Nonaccident Safety Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Primary Safety Factors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Secondary and Tertiary Safety Factors: Industry Safety Posture

Data Resources . . . . . . . . . . . . . . . . . . . . . .

Federal Safety Data Resources . . . . . . . .

FAA . . . . . . . . . . . . . . . . . . . . . . . ● . . . . . .

National Transportation Safety Board

NASA . . . . . . . . . . . . . . . . . . . . . .

RSPA . . . . . . . . . . . . . . . . . . . . .

Conclusions and Options . . . . . .

Box

4-A.

4-1.Commercial

Table

of Transportation

. . . . . . .

. . . . . . .

. . . . . . .

. . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . .

..... . . . . . . . . .....

. . . . . . . . . . . . . . . .....

. . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . ● ✎✎✎✎☛✎

✎ ✎ ✎ ✎ ✎ ✎ ✎ ✎ ✎ ✎ ✎ ✎ ✎ ✎ ✎ ✎ ✎ ✎ ✎ ✎ ✎ ✎

Box

Safety: Definitions . . . . . .

Accident

4-1. Safety Measures and Exposure Parameters 

Figure

Causal and

Tables

4-2. Federal Aviation Safety-Databases. . . . . . . .

Preventive

. . . . . . . . . .

. . . . . . . . . .

. . . . . .

. . . . . . . . . . . . . . . ●

✎ ✎ ✎ ✎ ✎ ✎ ✎ ✎ ✎ ✎ ✎ ✎ ✎ ✎ ✎ ✎

✎ ✎ ✎ ✎ ✎ ✎ ✎ ✎ ✎ ✎ ✎ ✎ ✎ ✎ ✎ ✎

✎ ✎ ✎ ✎ ✎ ✎ ✎ ✎ ✎ ✎ ✎ ✎ ✎ ✎ ✎ ✎

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Chapter 4

Safety Measurements and Data Resources

Transportation accidents account for only 2 percent of all deaths from any cause in the United

States annually, and the public readily accepts the

existence of travel risk. However, public concern

varies for different kinds of risk, and intense attention focuses on air transportation, even though the

fatality rate is very low. One reason maybe the relative perceptions of being in control of one’s destiny—

the operator of an automobile feels responsible for

his own fate; the passenger on board a public conveyance does not. Nonetheless, more people die in

private automobile accidents in an average month

in the United States than have died in commercial

aircraft accidents during the past 10 years.

A commercial aircraft crash, though a relatively

rare event, can result in the simultaneous deaths

of hundreds of people and often receives immense

public attention, while a similar number of isolated

fatalities is hardly noticed. The perceived loss to society is said to be proportional to the square of the

number of people killed in a single incident, implying that 10,000 individual deaths are the same as

100 at once, and that public preventive efforts

should follow accordingly.1

While sometimes irrational about safety, societies

do attempt to minimize risk to the extent feasible

and at an acceptable cost. Jimmy Doolittle expressed

this well in a report in 1952 to President Truman:2

The ‘Calculated Risk’ is an American concept

which gives mobility to the whole structure. The

phrase simply means a willingness to embark deliberately on a course of action which offers prospective rewards outweighing its estimated dangers. The

American public accepts the calculated risk of transportation accidents as an inescapable condition to

the enjoyment of life in a mechanical age. However,

the public expects and cooperates to . . . narrow the

gap between relative and absolute safety.

To know if risk is being reduced, one must be able

to measure it, and the first half of this chapter outlines a theoretical framework for nonaccident safety

data analysis. Collecting and analyzing many of

these data may not be practical or feasible, however, and the discussion is presented as a guide to

current safety data systems and their capabilities.

The last sections of the chapter present analyses of

existing safety databases and assess their utility and

limitations.

I Albert L. Nichols and Richard J. Zechhauser, “The perils of Prudence: How Conservative Risk Assessments Distort Regulation,” Regulation, November/December 1986, pp. 13-24.

‘Jerome Lederer, “Aviation Safety Perspectives: Hindsight, Insight,

Foresight,” Nineteenth Wings Club ‘Sight’ Lecrure, presented at the

Wings Club, New York City, Apr. 21, 1982, p. 3.

MEASURING TRANSPORTATION SAFETY

Safety Factors

In passenger transportation, safety factors are

events or procedures that are associated with or influence fatality rates. The probability of death (or

injury) as a result of traveling on a given mode, if

it can be quantified, is the primary benchmark of

passenger transportation safety. To be useful, alternative safety indicators must ultimately be correlated

to this benchmark. Vehicle accident rates are also

commonl y used as safety indicators, since most passenger fatalities occur as a result of vehicle accidents.

If risk is defined as the probability of death, past

risk in travling can be empirically determined from

fatality rates. Commercial aviation accidents involving large jets can result in the deaths of hundreds

of people; thus, a single accident can significantly

influence fatality rates. Consequently, trend analyses of fatality rates require data from time periods

of roughly 5 years or more, and these rates give poor

indications of short-term changes in risk.

Accident rates can be an alternative to fatality

rates as indicators of safety levels. While fatalities

are often associated with aviation accidents, the

number of fatalities, even for a specific type of accident, fluctuates considerably with each crash. The

number of accidents may have a smaller range of

yearly variance than the number of fatalities, but

69
70

‘k

Photo credit: National Transportation Safety Board

Major accidents result in tragic losses. Fortunately, such catastrophes are rare.

poses similar analysis problems. For example, midair

collisions involving large, commercial jets have

occurred twice in the United States during the last

10 years—little can be inferred from these numbers

regarding changes in collision risk. Since the number of accidents is small and can vary significantly

from one year to the next, accident rates are also

poor indicators of short-term changes in risk.

Safety factors other than fatalities or accidents

should be considered for prompt feedback on policy decisions or changes in the aviation operating

environment. The Federal Government and the

aviation industry maintain a wide assortment of

safety-related information. However, without consideration of the accuracy, completeness, and original purpose of these databases, safety trend analyses based on this information are meaningless.

Exposure Data

Understanding the measures that are the denominators of transportation accident or fatality rates

is necessary for safety analysis. The choice of which

exposure data type to use affects how the rates can

be compared across and within the transportation

modes. Passenger-miles (the number of passengers

multiplied by the miles traveled) are the best available exposure parameters for comparing air transportation with other modes and allow broad system comparisons.3 Risk per passenger-mile is not

uniform over a trip, and may vary by routing or

‘Trips between specific city pairs would be a better measure, since

the relative risks among different modes of travel between two points

is the primary safety concern. However, the total number of city pairs

in the United States is too large for comparative analysis and passenger data in this form are not readily available for some modes.
71

time of day. For example, the probability of an accident is significantly higher during takeoff or landing than while flying enroute; thus, most commercial aviation passenger-miles occur during much

lower than overall average risk conditions. (For further information, see chapter 5.)

Since the number of passengers per vehicle can

vary, vehicle-miles are often used to show exposure

when comparing accident rates. Risk may not be

uniform over each vehicle-mile traveled, and vehicle size and speed do not affect accident risk exposure

indicated by vehicle-miles.

An aviation accident fatal to one passenger is

likely to be fatal to many on board.4 Since most of

the risk involved with air transportation is associated with takeoff and landing, a 2,000-mile trip is

similar to a 200-mile trip when compared for safety.

Therefore, the number of trips (departures) is a valid

exposure parameter for air transportation, and both

passenger-departures (or -enplanements) and aircraftdepartures can be used.

Finally, time is a common measure of exposure

in many types of risk analyses. Flight-hour data are

necessary for economic, operational, and maintenance requirements of aircraft and airlines. Since

accurate data are kept, they are readily available as

exposure information.

No single measurement provides the complete

safety picture (see table 4-1). Passenger exposure data

are used when passenger risk is to be indicated, while

miles are used when it is important that the exposure

data not be influenced by vehicle size or speed.

Departure exposure data account for non-uniform

risk over a trip. Time is a generic exposure measure

in many fields, and data in that form are often readily available.

4

0n average, 50 percent of the passengers on board aircraft involved

in fatal accidents perish. (See chs. 5 and 7.)

Nonaccident Safety Data

Accident investigations often uncover pervasive,

but unrecognized, causal factors and can help prevent similar accidents from occurring. However,

since commercial aviation accidents are so rare,

other measures are needed for identifying short-term

changes in safety. The goal of nonaccident data analysis is to help prevent the first accident from happening.

Potential safety indicators are measurable factors

associated with or causally related to accidents, fatalities, or injuries. Ideally, the amount of data available will be large enough, unlike accident or fatality data, so that random events will have a small

effect on yearly trends. The diagram of aviation accident causal and preventive factors (see figure 4-1)

identifies sources for some nonaccident safety indicators.

In the diagram, items closely associated with accidents appear near the “accident” box. These offer the greatest potential as safety indicators and are

explained in the following sections. Factors more

removed from “accidents” have a correspondingly

long causal link to them. These factors are measured against more subjective standards and may be

more difficult to quantify -’’industry policy, ” for

example.

Measurement Methodology

Clear and precise definitions exist for aviation accidents (see box 4-A); the consistent and accurate

accident databases pose no problems for analysis

from a measurement standpoint. Moreover, in the

United States, every commercial aviation accident

is tracked by the National Transportation Safety

Board (NTSB), providing a complete set of aviation

accident and fatality data. However, other indicators require consideration of the measurement methTable 4.1 .—Safety Measures and Exposure Parameters

Critical events Exposure parameters

Injuries Passenger-miles Vehicle-miles

Fatalities Passenger-hours Vehicle-hours

Accidents Passenger-departures Vehicle-departures

Fatal accidents (or -enplanements) (or -trips)

SOURCE: Office of Technology Assessment, 1988.
72

.

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73

odology, because subjective influences and incom- is difficult. Additionally, many of the databases were

plete data affect analyses. designed for administrative support functions, not

While most of the potential nonaccident indica- as safety analysis tools.

tors discussed in this section can be extracted from

Federal and industry databases, in practice, they are Primary Safety Factors

not very useful for safety analysis. Much of the data Primary safety factors are those most closely corcome from voluntary reports submitted by pilots, related with accidents, and include incidents and

mechanics, or controllers. Despite safety reporting accident causal factors. Theoretically, they are the

requirements, ensuring compliance or consistency best substitutes or alternatives to accident data.
74

Incidents

Incidents are events that can be defined loosely

as “near-accidents.”5 Causal factors leading to accidents also lead to incidents, and all accidents begin as near accidents. The various combinations of

possibly unsafe acts and conditions that occur each

day usually end as incidents rather than accidents,

and the larger number of incidents offers wider opportunities for safety trend analyses and for suggesting potential accident prevention measures. However, for an aviation incident to be widely known,

it must be reported by at least one of the people involved. Yet, the definition of an incident is subject

to the interpretation of the observer, and what appears to be an incident to one person may not to

another. Thus, some information may be lost and

measurement error may occur. Similar errors will

result from incidents that are recognized, but not

reported. Various sampling techniques can be employed for testing database consistency, and valid

trend analyses are possible if errors in the data can

be estimated. Incident types include:

Near Midair Collision (NMAC).-An incident

associated with the operation of an aircraft in which

the possibility of collision occurs as a result of proximity of less than 500 feet to another aircraft, or an

official report is received from an aircrew member

stating that a collision hazard existed between two

or more aircraft.

Runway Incursion.–An occurrence at an airport

involving an aircraft, vehicle, person, or object on

the ground that creates a collision hazard or results

in loss of separation with an aircraft taking off, intending to take off, landing, or intending to land.

In-flight Fire. –A fire that occurs aboard an aircraft, whether or not damage occurs. Fire is extremely dangerous to aircraft and passengers because

of the confined nature of cockpits and cabins, the

amount and flammability of fuel, and the time involved in landing and evacuating an aircraft. Flight

crews are required to report occurrences of in-flight

fires to NTSB.

5The National Transportation Safety Board considers an incident

to be “. . . an occurrence other than an accident, associated with the

operation of an aircrafi, which affects or could affect the safety of operations.” 49 CFR 830.2 (Oct. 1, 1987).

Flight-critical Equipment Failure.—’’Flight-critical” is subject to various interpretations. Some examples are control system malfunctions and engine

failures.

Accident Causal Factors

Aviation accident investigations attempt to determine and understand the causes leading to accidents, in the hope of preventing future mishaps. The

findings can be grouped into five broad categories,

as shown in the causal factors diagram. Few accidents (or incidents) result from a single, isolated

cause—a combination of factors is usually involved.

An examination of these causal factors points to possible indicators for monitoring safety levels. The five

primary causal factor categories are discussed below.

Personnel Capabilities.–Human errors are factors in over two-thirds of commercial aviation accidents; they include lapses in attention, judgment,

or perception and deficiencies in knowledge or motor skills. Such errors may be caused by vehicle, environmental, or health factors, including cockpit layout, workload, fatigue, or stress. Aviation personnel

most subject to these errors include flight crewmembers, dispatchers, mechanics, and air traffic controllers.

In the operating environment, human errors are

difficult to identify for a variety of reasons, including privacy and sensitivity; for example, possible

measurements could include the results of periodic

or continuous monitoring of operating personnel.

However, human errors need to be understood to

be prevented. Some indicators of personnel capabilities which are presently measured and used in

either Federal or industry standards include employee duty hours, work hours, age, training, and

experience levels.

Traffic Environment.–The structure of the airways and airports and the level and composition

of air traffic heavily influence safety. Difficulties with

facilities or traffic routing are usually discovered

through incidents before an accident occurs. However, high traffic density puts continuous strains on

many aspects of the air traffic control (ATC) system.

For a given air traffic infrastructure, increased traffic density most likely correlates with an increased

risk of midair collisions. While the number of flight
75

operations can be accurately counted or estimated,

collisions occur too infrequently to correlate, and

NMAC statistics are not as precise. Operational error, operational deviation, and pilot deviation statistics are also potential air traffic safety indicators,

but have similar consistency problems. Controller

workload, the ratio of operations to controllers,

might provide insight on air traffic safety if the type

of ATC equipment being used and the nature of

the traffic mix are considered.

Aircraft Capabilities.—The failure of an aircraft

component is a factor in over 40 percent of jetliner

accidents. Examples of components include engines,

structural members, landing gear, control systems,

and instruments. Mechanical failures can result from

improper maintenance, design flaws, or operator

error.

Replacement or repair trends, especially for flightcritical components, are possible indicators of safety,

although the severity, along with the frequency of

the component failure must be considered in quantifying risk. The Federal Aviation Administration

(FAA), air carriers, and aircraft manufacturers maintain detailed databases of mechanical reliability data.

Analysis and communication of observed trends prevent most problems from becoming critical. Other

broad indicators include engine shutdown rates and

unscheduled landings due to mechanical difficulties.

Weather.—Modern aircraft can operate in virtually all kinds of weather, but unpredicted severe conditions, such as wind shear or heavy icing, can prove

deadly. Poor weather, compounded by mechanical

difficulties or errors in judgment, provides a comdwilliam R. Hendricks, dirwtor, Aviation Safety, Federal Aviation

Administration, attachment to letter t. OTA, Dec. 18, 1987. The Fed.

eral Aviation Administration defines an “operational error” as”, . . an

occurrence attributable to an element of the air traffic control system

which results in less than applicable separation minima between two

or more aircraft, or between an aircraft and terrain or obstacles and

obstructions as required by FAA Handbook 7110.65 and supplemental instructions. ”

An “operational deviation” is “. . . an occurrence where applicable

separation minima were maintained but loss in separation minima existed between an aircraft and protected airspace, an aircraft penetrated

airspace that was delegated to another position of operation or another

facility without prior approval, or an aircraft or controlled vehicle encroached upon a landing area that was delegated to another position

of operation without prior approval. ”

A “pilot deviation” is “. . . the action of a pilot that results in the

violation of a Federal Aviation Regulation or a North American Aerospace Defense Command (NORAD) Air Defense Identification Zone

(ADIZ) tolerance.”

mon scenario for aviation accidents. An understanding and timely monitoring of weather conditions is

required for safe operation of aircraft, as shown in

figure 4-1.

Unpredictable Events.—These are factors not included in the above categories, such as sabotage or

terrorism. By definition, unpredictable or random

events have no trends. Therefore, no unpredictable event indicators are possible except incidents and

accidents, which will show levels of past risk.

Secondary and Tertiary Safety Factors:

Industry Safety Posture

Commercial aviation safety is the dual responsibility of FAA and the airlines. Federal Aviation Regulations (FARs) set the framework for establishing

commercial aviation operating practices. Under the

current system, many practices tailored to individual carrier needs are allowable through programs

approved by FAA Principal Inspectors and Flight

Standards District Offices.

The commercial airline industry’s operating

practices—flight operations, maintenance, and

training—are a dominant influence on the traffic

environment, aircraft capabilities, and personnel capabilities causal categories discussed above.’ These

practices, along with the operation of the ATC system, are the secondary safety factors (see box 4-A).

The tertiary safety factors, furthest removed on

the accident/incident causal chain, affect the industry operating practices listed above. Industry* philosophy and policy, which differ among airlines, dictate operating decisions. Federal regulatory polic y

in turn influences industry policy and operating

practices. Qualitative assessments of the way operating practices affect safety performance are best

made by independent inspectors using objective

standards. In theory, FAA airline inspection programs are such assessments, although airline management and labor organizations receive relatively

little attention in FARs.

TManufacturers, through aircraft design and production, influence

aircraft capabilities, and noncommercial flyers and Federal policy affect the air traffic environment. These are assumed to be beyond the

direct control of the airlines.

8“Industry” includes airline management as well as labor unions.
76

Secondary Safety Indicators

FARs require the reporting of some data relevant

to operating practices. For example, air carrier traffic,

schedule, and financial information must be periodically submitted to the U.S. Department of Transportation (DOT). These data illustrate differences

among carriers and over time, but as currently reported and reviewed, no correlation with safety has

been established. Some examples of potential safety

indicators are given below.

Flight Operations.—With the increased use of

hub and spoke networks and the limits of the ATC

system, airline flight crews and maintenance operations have felt new demands. While each airline

will handle similar pressures differently, the trends

in the indicators are important to understand. Some

examples include: aircraft daily utilization (number

of hours per day an aircraft is used); departures per

aircraft per day; percent of fleet required for daily

operations; and percent of flights into high density

airspace.

Maintenance.– The aircraft capability indicators

discussed previously are applicable measures of maintenance quality, though equipment design and manufacturing quality are important also. Unit maintenance costs can be used, but there are many

reasons for variations among carriers and over time,

such as productivity and technological changes.

Training.– Possible indicators include the number of hours of a type of instruction per applicable

employee and the use of certain nonmandatory but

valuable options, such as simulators, cockpit resource management, and wind shear training.

Tertiary Safety Indicators

FAA safety audits for regulatory compliance could

indicate airline management attitude, organizational

skill, and operational safety. While inspection data

are subject to the personal biases of the individual

inspectors, the use of objective inspection guidelines

and standards, consistent and periodic audits, and

varying inspection teams make inspection results

valid measures of safety trends. Regulatory compliance data differ from previously discussed indicators in that the exposure parameters will no longer

be miles, departures, or hours. Since FAA inspectors examine only a small percentage of an airline’s

records, aircraft, and operations, a measure of the

quantity of inspection is needed in order to normalize the data used for analysis. For example, an inspection of 10 percent of the records of a large carrier would probably find more faults than a 10

percent examination of a small carrier. A measure

of a carrier’s exposure to inspection, such as the

number of inspector man-hours performed or the

number of records or operations examined, would

be used as the denominator in the indicator ratio.

The number of violations per inspection man-hour

is an example of a regulatory compliance measure.

With appropriate guidelines, the quality of management practices could be measured by inspector

assessment and ranking of certain aspects of airline

operations. For example, two airlines may meet all

Federal standards, but one may still be noticeably

“safer” than the other. Objective standards are

needed to permit consistent analyses across industry and time.
77

DATA RESOURCES

The Federal Government collects vast amounts

of aviation data to support its responsibility for overseeing aviation safety, and automated systems are

required for effective data processing. However,

OTA research indicates that the analytical qualities of electronic data management systems and their

data vary significantly among and within the Federal agencies dealing with aviation safety. The

amount and caliber of safety data are significantly

better for commercial aviation than for other transportation modes, but major barriers prevent effective use of the data. While frequently-cited accident

and fatality statistics reflect past risk, a comprehensive program using Federal databases could identify

and monitor changes in commercial aviation safety

in a more timely manner. The central difficulties

of such a program are:

● the consistency and availability of appropriate

safety data,

● the accessibility and compatibility of various

data systems, and

. an emphasis on administrative purposes in the

design and use of the databases that makes analysis difficult.

These problems are not new. A 1980 General

Accounting Office (GAO) report stated that FAA

had not been effective or timely in developing systems to identify safety hazards.9 The report futher

explains that:

. . . although FAA’s hazard identification efforts

have been numerous and varied, they have been

hindered by insufficient information gathering,

limited analysis that has not fully employed state

of the art capabilities, and an inadequately planned

and coordinated agency approach. ”10

A “blue-ribbon” committee of the National Research

Council concurred with these findings and recommended that “. . . the FAA accelerate its development of an effective information-gathering and data

system. ”11

W.S. Congress, General Accounting Office, How To Zmprove rhe

Federal Aviation Administration’s Ability To Deal With Safety Hazards, GAOiRCED 80-66 (Washington, DC: Feb. 29, 1980), pp. 5-17.

‘qbid, p. 5.

1 INational Rmearch Council, Assembly of Engineering, Committee

on Federal Aviation Administration Airworthiness Certification Procedures, Improving Aircrafi Safety: FAA Certification of Commercial

Passenger Aircraft (Washington, DC: National Academy of Sciences,

1980), p. 66.

Using the safety indicator theory developed earlier

in this chapter, OTA reviewed a wide assortment

of Federal aviation safety databases in an effort to

document changes in commercial aviation safety

during the past decade. A number of these databases contain ostensible safety indicator data (see

table 4-2), but in practice, the nonaccident information has numerous shortcomings and is of limited

use for safety trend analysis. An overview and assessment of each of the databases listed in table 4-2 are

presented in this section, and uses and potential uses

for these databases are given. (OTA analyses of these

and other data are presented in chapter 5.)

Federal Safety Data Resources

DOT, which has regulatory responsibility for

transportation safety, maintains the largest amount

of aviation data. Within DOT, FAA, which monitors all aspects of aviation safety, and the Research

and Special Programs Administration (RSPA) are

responsible for the collection and management of

safety and economic-related information. NTSB and

the National Aeronautics and Space Administration (NASA) also keep specialized aviation safety

data.

FAA

FAA is responsible for promoting aviation safety,

achieving efficient use of airspace, operating an air

traffic control system, and fostering air commerce.

In support of these missions, FAA collects a wide

range of aviation information and operates over 280

automated data systems.12 Three organizations

within FAA, the Associate Administrator for Aviation Standards, the Associate Administrator for Air

Traffic, and the Office of Aviation Safety collect and

manage most of the safety-related data.

Associate Administrator for

Aviation Standards

Aviation Standards (AVS) personnel, working

out of regional and field offices across the United

States, collect and review large quantities of data

12U,S. Department of Transportation, Federal Aviation Administration, information Resources Management Plan, Volume H: Systems

Plan FY87-FY89 (Washington, DC: December 1986), p. 167.
78

Table 4-2.—Federal Aviation Safety Databases

Federal Earliest

Data type Database agency year a Storage system for historical data

Accident/incident Aviation Accident Data

System

Accident/incident Accident Incident Data

System

Incident Aviation Safety Reporting

System

Incident Near Midair Collision

Database

Incident Operational Error Database

Incident Pilot Deviation Database

Mechanical reliability Service Difficulty Reporting

System

Air Operator Data System

Traffic levels Air Traffic Activity Database

Operational practices Air Operator Data System

Air Carrier Statistics Database

Inspection results Work Program Management

System

Violation/enforcement Enforcement Information

actions System

NTSB

FAA

NASA

FAA

FAA

FAA

FAA

FAA

FAA

FAA

RSPA

FAA

FAA

1982

1978

1975

1980

1985

1985

1978

1980

Previous

18 months

1980

1988

1987

1983

Digital DEC-10; published reports

Boeing Computer Services IBM

3084; Data General MV-15000

Battelle Columbus Laboratories:

VAX integrated computer cluster

IBM/AT; published reports

IBM/AT; published reports

IBM/AT; published reports

Boeing Computer Services IBM

3084; Data General MV-15000;

published data

Boeing Computer Services IBM

3084; Data General MV-15000;

published data

Published reports

Data General MV-15000; published

data

Digital DEC-10; published reports

Data General MV-15000

Boeing Computer Services IBM

3084-

: Data-General MV-15000

KEY: NTSB - National Transportation Safety Board; FAA = Federal Aviation Administration; NASA = National Aeronautics and Space Administration; RSPA = Research

and Special Programs Administration.

aEarliegt year for data stored electronically.

SOURCE: Office of Technology Assessment, 19S8

as well as certificate aircraft, airmen, and airlines;

oversee and enforce Federal Aviation Regulations;

and investigate aircraft accidents and incidents.

Many of these data are entered into the numerous

databases maintained in Oklahoma City at the Mike

Monroney Aeronautical Center and the Aviation

Standards National Field Office (AVN).

The AVN and Aeronautical Center databases,

used primarily to support administrative AVS tasks,

reside on various computer hardware. Most of the

data systems are hosted by the Aeronautical Center’s IBM-3084 mainframe or AVN’S Data General

MV-15000 minicomputer, though some operate on

the MV-8000’S located at each regional office, the

Burroughs B20 workstations distributed throughout FAA or the Transportation System Center’s

Digital DEC-10. Some of the systems, while required

for the daily operation of AVS, are less important

for analyzing system safety. Examples include databases containing airmen and airline certification

records, medical records, aircraft registry and airworthiness information, and regulatory history.

AVN does maintain four data systems which are

used, or can be used, for safety analyses. These databases, containing information on aviation accidents

and incidents, mechanical difficulties, regulation violations, and aircraft utilization and reliability, will

be discussed in this section.

Some of the limitations of these independent and

incompatible safety data systems have been recognized by FAA. The FAA Information Resources

Management Program Office described the problems

that arose from the lack of coordination during the

development of the specialized data systems:

Little consideration was given to the information

requirements of other organizational elements

within the agency. This approach has resulted in

a number of fragmented data systems that contain

nonstandardized data, having limited access, and

do not satisfy the needs of all users. In addition, the
79

data contained in these systems are not always current and lack the accuracy necessary to effectively

meet the agency’s program objectives.13

FAA is developing the Aviation Safety Analysis System (ASAS) to integrate and standardize current

and future databases and maintain them on a central host computer linked via a telecommunication

network to workstations located at all AVS facilities. An overview of ASAS is given later in this

section.

The hardware and software compatibility problems limit the ease with which data are transferred

between field personnel and AVN. With the exception of enforcement and inspection information, at

present, data can be entered into the systems only

in Oklahoma City. While this limits input errors

(effectively, only one or two people enter data per

database), timely responses are impossible. Though

the field offices have access electronically to most

of the systems, the databases are so intricate that

data requests usually require processing by the limited number of AVN personnel.

Another option available to AVS personnel, as

well as to any interested party, is a commercial

timeshare network that presently contains three of

the safety data systems. Operated by Boeing Computer Services, the system enables users to access

the complete on-line FAA databases for accidents

and incidents, service difficulty reports, and enforcement cases. Historical data, from as many as 5 previous calendar years, can be extracted in standard

or custom-designed formats.

FAA Accident Incident Data System.–Accident

data provide the key means of measuring aviation

safety. An understanding of underlying accident

causes and trends leads to preventive measures.

Responsibility for investigating all civil aircraft accidents in the United States rests with NTSB,14

though authority is delegated to DOT and FAA for

certain accidents.15 Both FAA and NTSB officials

collect accident data, but NTSB alone determines

probable causes. FAA is responsible for ensuring

aviation safety, and investigates accidents primar1]U.S. Department of Transportation, Federal Aviation Administration, Information Resource Management Plan, Volume I: Strategic

Overview (Washington, DC: December 1986), p. 22. 1449 CFR 800.3 (Oct. 1, 1987).

1549 cm 800, app. (Oct. 1, 1987).

ily to assess whether corrective action is required

in the aviation system. In January 1984, both agencies began using common forms, the NTSB series

6120, for the reporting of accident data. While efforts are underway to develop a joint NTSB/FAA

accident database, both agencies currently maintain

separate data systems. There is considerable, but not

complete, overlap between the two systems. The

NTSB Aviation Accident Data System contains all

U.S. civil aircraft accidents and selected incidents,

while the FAA Accident Incident Data System

(AIDS) has fewer accident records, but substantially

more incident data than the NTSB system.

AIDS contains general aviation and air carrier incidents dating from 1978, and general aviation accidents from 1973. In 1982, as a step toward the

common NTSB/FAA accident database, air carrier

accident information was introduced to the system.

Though the NTSB database is considered the definitive source for aircraft accident data, AIDS is

more accessible to FAA personnel on a daily basis.

Copies of completed accident reports are forwarded

from NTSB to AVN, where the data are entered

into the Data General MV-15000 minicomputer.

While NTSB investigators also use the common

series 6120 forms for reporting incidents.16 AVS

personnel use the less detailed FAA Form 8020-5.

The completed FAA reports are sent to Oklahoma

for processing and review, where contract personnel classify the incidents and assign probable cause

factors. Other AVN employees encode and enter

the incident information into the data system. However, the reports are not verified and no procedure

is in place for ensuring consistent reporting from

the field. OTA found substantial variation in the

incident reporting rates among the FAA regions (see

chapter 5).

AIDS data are available to FAA regional offices

and headquarters via the commercial computer

timeshare system operated by Boeing Computer

Services or by printouts from AVN. OTA finds that

while separate analyses of incident or accident data

MB regulation, aircra~ operators must notifi the National Trans- Y

portation Safety Board of five types of incidents (49 CFR 830.5), which

may be investigated depending upon the circumstances and National

Transportation Safety Board workload. This results in approximately

30 air carrier reports per year from the Board, compared with over

1,400 reports by Federal Aviation Administration investigators.
80

are possible, comparisons of accidents and incidents

are difficult because FAA uses different terminology in classifying incidents than NTSB uses in accident/incident reports. OTA devised an algorithm

for reorganizing FAA data into the NTSB format,

and requested that AVN use it in extracting commercial aircraft accident and incident data. AVN

provided little useful automated support. The algorithm required searches and combinations of

AIDS data fields; OTA received unwieldy printouts

of a portion of the data requested. Even if the missing information were available, extensive manual

processing would be necessary to format the data.

While NTSB and NASA provide detailed analyses of the accident and incident data they maintain,

FAA examines air traffic incident data only. In 1984,

the Safety Analysis Division of AVS was moved to

the newly formed Office of Aviation Safety. Consequently, AVS does not have the resources to analyze air carrier incident or other data maintained

in Oklahoma City. While sufficient information,

such as causes and factors, is collected, it is not used

in measuring and monitoring aviation system safety

or to assist in setting regulations.

Enforcement Information System.–Theoretically, trends in the airline industry safety posture

could be determined from the results of regulatory

compliance audits performed by FAA inspectors. To

accomplish this, the number and type of violations

per carrier and some measure, such as inspector

man-hours, of each airline’s exposure to inspections

would be needed. However, while all enforcement

actions are tracked and recorded in the Enforcement

Information System (EIS), little information is available on the number of inspections performed or the

amount of time spent on them. *7

EIS, which is managed by AVN on the MV-15000

minicomputer in Oklahoma City, was designed and

is used primarily for administrative purposes. In support of AVS and General Counsel personnel, EIS

tracks the complete history of each enforcement case

and keeps copies of all documentation. Electronic

records are available from 1963 to present. Because

of the sensitivity of the data, only closed cases are

available to the public.

17U.S. Congress, General Accounting Office, Aviation Safety:

Needed Improvements in FM Airline Inspection Program are Underway, GA()/RCED 87-62 (Washington, DC: May 1987), pp. 24-38.

EIS is the only AVN system that allows input

directly from the field offices; the others require that

the field personnel send paper copies of the data to

Oklahoma City for processing by AVN personnel.

Service Difficulty Reporting System.–The mechanical reliability of aircraft and components is

monitored by AVN analysts through the Service

Difficulty Reporting System (SDRS). Reports, required by regulation,18 are filed by air carriers, repair stations, manufacturers, FAA inspectors, and

others concerning specific types of aircraft failures

or malfunctions. These reports arrive at AVN in

paper form where the data are encoded and entered

into the MV-15000 minicomputer.

While containing data for over 10 years, SDRS

is most useful for detecting short-term safety problems. The SDRS program automatically tracks

trends in reports according to aircraft and component type. If the monthly or annual trend in reports

exceed a pre-set value, then the system automatically

alerts AVN analysts. An airworthiness directive,

warning, or alert is issued to the public if, after review, the trend alert proves serious.

SDRS data are rarely used for long-term analyses. Due to the nature of the system, long-term adverse trends avoid detection since they have such

shallow slopes they do not set off the alerting system. Also, since mechanical difficulties are often discovered during maintenance inspections, the frequency and depth of these inspections, along with

the willingness of the airlines to file reports, affect

the SDRS database.

Air Operator Data System.–AVS personnel

must frequently refer to information about air carriers and other commercial operators and the structure of their organizations, fleets, and facilities. While

such information is available in fragments from

many sources within DOT, the Air Operator Data

System (AIROPS) attempts to consolidate the vital

data available from within FAA. Of interest for

safety analysis are data involving aircraft operations,

such as utilization and engine reliability.

Unlike other AVS data gathering efforts discussed

(accident/incident, enforcement, service difficulties),

there is no regulatory requirement for air carrier

’

8

14 CFR 121.703 and 14 CFR 135.415 (Jan. 1, 1987).
81

reporting or FAA collection of “air operator” data

as such. ” Air carrier inspectors, though, follow

general guidelines for collecting the data monthly.

They send air operator data to Oklahoma City by

mail for processing. While AVN employees ensure

accurate transcription of data, there are no procedures in effect for ensuring accuracy at the source.

The National Air Transportation Inspection (NATI)

Program, which relied on AIROPS for many of its

activities, discovered many errors in the data. The

NATI report concluded that the Air Operator Data

System is “. . . in need of corrections and enhancements. “2° Data have been collected and published

in the monthly Air Carrier Aircraft Utilization and

Propulsion Reliability Reports since the 1960s,

though due to contractor problems, no reports were

released between January and August 1987.21

Air operator data provide the opportunity for

analyzing certain air carrier operating practices, by

individual company or industry wide. When used

in conjunction with other system information, daily

utilization data give one view of the amount of

schedule pressure placed on aircraft fleets. Engine

reliability data, the basis for overwater flight certification, indicate the final product of equipment

design and airline maintenance and operating procedures.

Work Program Management Subsystem.–FAA’s

struggles to modernize its air carrier inspection program are documented in a recent GAO report.22

FAA senior management and safety analysts knew

little about the inspections being performed during

the post-deregulation period. The only attempt at

using inspection results for analysis followed the

NATI Program in 1984. The NATI Task Force,

comprised of former FAA inspectors, reviewed the

NATI reports and found that over 20 percent of

the carriers analyzed had a “less than desirable comlgAir Camiers must repo~ organizational, operational, and financial

data to the Research and Special Programs Administration’s Office of

Aviation Information Management (and previously to the Civil Aeronautics Board) as required by 14 CFR 241 and 14 CFR 298. Certain

engine problems must be submitted via mechanical reliability reports

as stated in 14 CFR 121.703 and 14 CFR 135.415.

‘OU.S. Department of Transportation, Federal Aviation Administration, “National Air Transportation Inspection Program,” report for

the Secretary, Mar. 4-June 5, 1984, p. 36.

~lThe data were consolidated and released in special reports in fall

1987.

2JGeneral Accounting Office, op. cit., footnote 17.

pliance posture,”23 and that FAA inspector surveillance and enforcement needed improvement.24

The NATI Program also identified FAA problems

in collecting and managing inspection data.25

Even before NATI occurred, FAA was planning

an automated system for tracking the inspection program. However, the Work Program Management

Subsystem WPMS), implemented in October 1984,

has been plagued by problems. The microcomputers,

on which the inspection data are entered, have insufficient capacity for the system requirements. Additionally, there are not enough of the computers

to go around. Moreover, FAA installed inadequate

software in the system, limiting the type and extent

of the inspection data available for analysis.

Changed in October 1986, the current software

provided some usable data in fiscal year 1987. FAA’s

Western Pacific Region has successfully utilized

WPMS for inspection efforts, though it still cannot

access the central computer in Oklahoma City.

WPMS has aided FAA’s geographic inspection concept by allowing field inspectors throughout the

United States to send inspection results directly to

the carrier’s respective principal inspector.

Though designed primarily as a tool for managing the FAA inspection program, WPMS can potentially be used for safety analysis. WPMS data,

centrally stored at AVN, enable a compilation of

inspection results and a measure of exposure

(inspector-hours).

Using the Data Systems for Analysis

OTA found few presentations, let alone analyses,

of the safety data contained in the AVS data systems. Moreover, the systems are difficult to use for

safety analyses for two fundamental reasons. First,

AVN exercises little quality control of data collection and reporting, because it has neither the manpower nor the imperative to do so. Furthermore,

no plans are underway for ensuring that FAA field

personnel or airlines collect and report accurate data.

23U.S. Department of Transportation, Federal Aviation Administration, “Memorandum on Evaluation of National Air Transportation

Inspection Program Inspection Reports,” April 1985, p. 37.

241bid, p. 41.

15 Federal Aviation Administration, op. cit., footnote 20, p. 23.
82

Second, extracting useful data from an established

database requires not only an understanding of the

safety problem to be analyzed, but knowledge of the

limitations of the computer systems and the intricacies of the data fields. These AVN data systems were

not designed as analytical tools, and AVN personnel are not trained analysts. FAA plans to address

some aspects of this problem by implementing the

Aviation Safety Analysis System (ASAS), which,

as envisioned, will consolidate and standardize new

and existing safety databases. In contrast to the

present system, FAA personnel without extensive

training in computer programming will have access

to a wide range of safety data via desktop workstations.

ASAS was conceived in 1979 to build upon the

general office automation program for regional and

field offices then in development at FAA. New office equipment, proposed as part of the automation

program, was to have sufficient processing and network capabilities for an integrated safety data system. The numerous compatibility and communication difficulties created by the data systems then in

use (for the most part, still in use) at FAA were to

be addressed by ASAS. An ASAS Program Office

was established in 1982 and a long-term phased development plan was proposed. The initial phase will

integrate and standardize current data systems. Subsequent phases will implement and develop new

databases.

—

Photo credit: Federal Aviation Administration

FAA inspectors and safety analysts need ready access

to complete and accurate data.

The types of ASAS databases fall into four categories: 1) airworthiness data; 2) regulatory data; 3)

operational data; and 4) organizational information.

Airworthiness data are mainly historical information on aircraft, such as mandatory modifications

specified by FAA. Regulatory data consist of background information, such as Notices of Proposed

Rulemaking, legal opinions, and previous regulations. Data describing the aviation environment are

included in the operational category. These databases track airmen, aircraft, and operators along

with accidents, incidents, mechanical reliability

reports, and enforcement actions. The work management subsystems to monitor AVS tasks, such

as airline inspections, fall into the category of organizational information.

ASAS will alter many of the tasks currently performed by AVS personnel. Data will be entered and

validated where it is collected and generated, at the

field office level. This increase in employee exposure

to automated systems implies a need for substantial training and for user-friendly equipment and

software. The problems with WPMS, discussed

earlier, illustrate the need for proper training and

technology. It is also proposed that field personnel

will be able to perform their own data analyses using

information from several databases through analytical software packages.

Associate Administrator for Air Traffic

In managing the National Airspace System

(NAS), Air Traffic (AAT) personnel control traffic, operate facilities, and develop procedures and

standards for airways, airspace, and flight operations. On a daily basis, information is collected and

reviewed concerning air traffic levels, NAS status,

system errors, controller errors, pilot deviations, and

delays, although most of the data are entered into

automated systems only after reaching specific offices

within FAA headquarters. Other offices, regions,

or field facilities within AAT do not have ready access to many of these systems.26 However, Office of

Air Traffic Evaluations and Analysis specialists monitor every report on operational errors, NMACs,

‘%J.S. Department of Transportation, Federal Aviation Administration, Information Resource Management Plan, Volume 1: Strategic

Overview (Washington, DC: October 1985), p. 14.
83

and pilot deviations and communicate findings to

the field facilities.27

While AAT tracks and analyzes air traffic safety

data, it does not manage the data systems dealing

with incidents or system-wide operational information of interest to this study. The Office of Aviation Safety (discussed in the next section), handles

the incident data while the air traffic activity data

are processed by the FAA Office of Management

Systems. The Office of Air Traffic Evaluations and

Analysis is developing its own data system, the

Operational Error Reporting System, to receive and

track operational error reports in a timely fashion.

The system has been on-line, linking a number of

regional offices with headquarters, since June 1987.

Air Traffic Activity Database.–An essential exposure measure for air safety analysis is the level of

traffic. One parameter, departures, is the best exposure reference for general safety comparisons.

While departure data are available for specific carriers from Civil Aeronautics Board records and

RSPA, system-wide traffic data, including departures, are available from the Air Traffic Activity

Database.

Air traffic control personnel keep track of the daily

activity at ATC facilities. Monthly summaries of

various operations, including the number of takeoffs

and landings at airports with control towers and the

number of aircraft handled by radar control facilities, are submitted to the Office of Management

Systems in FAA headquarters. There the data are

encoded for entry into the Boeing Computer Services System, where they are processed and crosschecked. Due to the large volume of monthly data,

the Boeing system is not used for analysis or storage, but as a tool for preparing summary reports.

Annual Air Traffic Activity Reports are published

and are available to the public.

Facility, region, or system-total data are available,

with tables categorizing information by aircraft operator (air carrier, air taxi, general aviation, and military). This study used historical tower activity data

to illustrate the growth of hubs and as the exposure

reference for air traffic incidents. The number of aircraft handled by en route radar controllers is an

alternate measure of traffic trends.

27B Keith pott~, ~~~miate administrator, Air Traffic, Federal Aviation Administration, personnel communication, Dec. 22, 1987.

Office of Aviation Safety

Reporting directly to the FAA Administrator, the

Office of Aviation Safety conducts accident investigations, safety analyses, and special programs. In

this role, it monitors or manages several databases.

The Office of Aviation Safety operates the National

Airspace Incident Monitoring System, an automated

system containing NMAC, operational error, and

pilot deviation databases. FAA maintains contact

with the NASA-administered, but FAA-funded,

Aviation Safety Reporting System through the the

Safety Analysis Division within the Office of Aviation Safety.

Near Midair Collision Database.–FAA learns

about NMACs primarily from pilot reports, though

air traffic controllers, passengers, and ground observers also serve as notifiers. In each case, a preliminary report is filed and must be investigated by

FAA within 90 days.

Although the AVS Accident Incident Data System tracks NMACs, they are not included in its

database. All incident reports involving air traffic

operations, including NMACs, end up in the Office of Aviation Safety. There, the data are encoded

and entered into an IBM/AT personal computer

system located at FAA headquarters. NMAC information from 1980 to the present is available in the

system. FAA has had widely publicized difficulties

with its NMAC data, and instituted a monitoring

procedure in 1985 to ensure proper handling of

NMAC reports. An interagency task group consisting of FAA, NASA, and the Department of Defense was formed in 1986 to review existing NMAC

data and recommend ways to reduce the midair collision threat. The recommendations cover equipment, airspace structure, data reporting, and pilot

training. Additionally, the Office of Aviation Safety

is presently conducting a number of NMAC studies.

Operational Error Database.–The loss of legal

flight separation around an aircraft which is attributed to the ATC system is an operational error

(see footnote 6). For example, during en route operations, controllers are required to keep aircraft apart

by 5 miles horizontally and 1,000 feet vertically for

flights below 29,000 feet and 2,000 feet vertically for

flights above. Operational deviations, generally less

serious than operational errors, do not involve loss

of separation between two aircraft, but result from
84

an aircraft passing too close to a restricted airspace

or landing area.

From 1983 to 1985, FAA instituted two changes.

First, the enroute ATC computers were reconfigured

with the Operational Error Detection Program

which automatically records and reports any loss

of proper separation for aircraft in the system. Second, the responsibility for maintaining an operational error report database was shifted to the Office of Aviation Safety. Preliminary reports of

operational errors and deviations are filed from the

ATC facility within 48 hours after the event’s occurrence. All reported operational errors and deviations

are investigated, and depending on the outcome,

a final report is submitted. Personnel from the Office of Aviation Safety encode and enter preliminary and final report data into the IBM/AT.

Pilot Deviation Database.–An ATC facility

that observes a pilot deviation is responsible for

reporting it to the appropriate Flight Standards office for investigation. Prior to 1985, incidents involving pilot deviations were entered into AVN’S Accident Incident Data System, though they were not

specifically categorized as pilot deviations. Presently,

the results of pilot deviation investigations are sent

directly to the Office of Aviation Safety where the

data are entered into an IBM PC. The Office of

Aviation Safety is responsible for tracking and

reporting trends in pilot deviations, and published

its first statistical report of pilot deviations in October 1987.28 Similar to the operational error data,

pilot deviation information stored electronically extend back only to 1985.

NTSB, in a special investigation of runway incursions, found that as with operational errors, many

pilot deviations are not being formally reported but

are resolved informally at the ATC facility involved. 29 Additionally, prior to 1985, reports

reaching Flight Standards were investigated primarily to determine violation and enforcement actions

against the pilot involved, not for safety analysis.30

The number of pilot deviation reports processed by

28U.S. Department of Transportation, Federal Aviation Administration, Selected Statistics Concerning Reported Pilot Deviations (1985-

]986) (Washington, DC: October 1987).

z~atlona] Transportation Safety Board, special ~nVeS@arrOn ‘eport-Runway Incursions at Controlled Airports in the United States,

NTSB/SIR-86/01 (Washington, DC: May 6, 1986), p. 8.

‘Tbid, p. 8.

the Office of Aviation Safety is increasing every year

(over 2,500 in 1986), though how much of that

growth should be attributed to changing reporting

practices is open to question.

National Transportation Safety Board

NTSB is responsible for investigating all aircraft

accidents and certain incidents, determining their

probable causes, and making recommendations to

FAA. It keeps an extensive database of accident information in an automated system and publishes

accident reports and the results of other special investigations.

Aviation Accident Data System.–Since its inception in 1967, NTSB has kept records of civil aircraft accidents.31 The current automated database,

the Aviation Accident Data System, contains information on aviation accidents and incidents. Primarily designed for administrative purposes, the system does have analytical capabilities. NTSB

publishes Annual Reviews of Aircraft Accident Data

and occasional Special Studies, which are supported

by statistical analyses accomplished with the data

system.

The NTSB Aviation Accident Data System contains information on every known civil aviation

accident 32 in the United States. Selected incidents,

as listed in 49 CFR 830.5, are also included in the

database. The system encompasses data from 1962

to the present, though changes were made in reporting methods during this period. A single format was

used until 1982, when the procedure and report form

was revised. The documentation was again changed

in 1983, when NTSB accident investigators began

submitting data in the format that was eventually

adopted as NTSB series 6120.4. The data from the

reports are entered into the computer, along with

the findings of probable cause and contributing factors. Computer searches are possible with any data

block or group of blocks as selection criteria.

Differences in data formats impose some restrictions on possible computer-assisted analyses. For example, in 1982, NTSB changed its method of clasJIFrom 1940 t. 1967, the Civil Aeronautics Board investigated accidents. IZAccidents involving only militaq or public-use airCrafi are not usually investigated by the National Transportation Safety Board.
85

sifying accidents. Accidents are now categorized by

the first “occurrence” in the sequence of events that

led to the accident. Earlier, groupings were made

by the accident “type.” NTSB has developed a matrix for comparing occurrences and types. For broad

safety studies, the effect of the format changes is

small. While the collection of data has essentially

remained the same, the latter format allows a more

detailed analysis of accident circumstances.33

NASA

NASA, which provides and supports aviation research and development, administers the confidential and voluntary Aviation Safety Reporting System (ASRS). ASRS is designed to encourage reports

by pilots and air traffic controllers concerning errors and operational problems in the aviation system, by guaranteeing anonymity and immunity from

prosecution for all reporters. ASRS data can provide an alternate Federal insight into the nature and

trends of aviation incidents.

NASA Aviation Safety Reporting System.–

ASRS is a joint effort by FAA, NASA, and the Battelle Memorial Institute to provide a voluntary

reporting system where pilots, controllers, and

others can submit accounts of safety-related aviation incidents. The system is funded mainly by

FAA, administered by NASA, and maintained by

Battelle. Reports are sent to the ASRS office at

NASA Ames Research Center and the data are analyzed and entered into a computer by employees of

Battelle. The database is maintained at Battelle Columbus Laboratories in Ohio.

Prior to the establishment of ASRS in 1976, attempts at providing voluntary incident reporting

programs met with little success. Potential reporters

feared liability and disciplinary consequences. Even

after FAA introduced its Aviation Safety Reporting Program (ASRP), which offered limited immunity and anonymity to participants, few reports were

submitted. The aviation community feared that

FAA, responsible for setting and enforcing regulations, would misuse the data. FAA acknowledged

these concerns and transferred control of ASRP to

‘

]National Transportation Safety Board, Annual Review of Aircrafi

Accident Data, U.S. Air Carrier Operations, Calendar Year 1982,

NTSB/ARC-86/01 (Washington, DC: n.d.), p. 1.

a neutral third party, NASA. A Memorandum of

Agreement was executed between FAA and NASA

in August 1975, establishing ASRS. The Agreement

provided for a limited waiver of disciplinary action,

confidentiality of reporting sources, and an Advisory Committee comprised of representatives of the

aviation community. ASRS became operational on

April 15, 1976.34

Voluntary reports, useful for understanding the

nature of incidents, are somewhat deficient in indicating prevalence or frequency. Therefore, ASRS

was planned as an “analytical rather than a descriptive system. ”35 The ASRS report form (NASA

Form ARC 277) was designed to gather the maximum amount of information without discouraging

the reporter. Structured information blocks and key

words are provided, not only to guide the reporter,

but to aid subsequent data retrieval and research.

Narrative descriptions are encouraged. Space is provided for the reporter’s name, address, and telephone number. This permits NASA to acknowledge the report’s receipt by return mail, and also

allows the Battelle analyst to contact the reporter

for followup data. Information that identifies the

reporter is deleted before being entered into the

computer.

Under the guidance of NASA, Battelle receives

the incident reports, processes and analyzes the data,

and publishes reports of the findings. Human factors in aviation safety, a continuing concern at the

NASA Ames Research Center, were a major consideration in ASRS development. The data analysts,

primarily experts in aircraft operations and air traffic

control, provide insight into the nature of the human error or other underlying factors in the incidents. Although the reports are encoded in detail,

the complete narrative text of each report is retained

for later re-evaluation.

Because ASRS is voluntary and reporters are

deidentified, a concerted effort among a number of

J+ William D. Reynard, Aviation Safety Reporting System, in U.S.

Congress, House Committet on Science and Technology, Subcommittee on Investigations and Oversight, Aircrafi Safety Technologies

(Washington, DC: U.S. Government Printing Office, Nov. 23, 1985),

p. 29.

‘5Charles E. Billings, M. D., the National Aeronautics and Space

Administration Ames Research Center, “Human Factors in Aircraft

Incidents: Results of a 7-Year Study,” Aviation, Space, and Environmental Medicine, October 1984, p. 961.
86

individuals can distort the database. For example,

air traffic controllers at certain facilities increased

their reporting of incidents associated with a display system that they wanted upgraded. This reporting campaign ended with the air traffic controllers

strike in August 1981.36

RSPA

The Office of Aviation Information Management

of RSPA assumed the former Civil Aeronautics

Board’s responsibility for collecting data on airline

operations, traffic, and finances beginning in 1985.

Airlines submit data periodically in accordance with

14 CFR Parts 217, 234, 241, 291, and 298. While

these data do not directly indicate safety, they do

provide measures of exposure such as departures,

hours, and miles. However, the airline categories for

exposure data reporting do not correspond to the

operating categories used by NTSB for classifying

accidents, resulting in some gaps and inaccuracies

in statistics. Financial statistics also have potential

uses in analyses, since many in industry and government believe that economics influence safety to

some degree.

Air Carrier Statistics Database.–Part 217 Reporting Data Pertaining to Civil Aircraft Charters

performed by U.S. and Foreign Air Carriers (14

CFR 217) requires U.S. and foreign air carriers to

file traffic data on any civilian international charter flight flown to or from the United States in large

aircraft (over 60 seats or 24,000 pounds of payload).

The information reported quarterly shows the charter passengers or tons of cargo flown between the

origin and the destination point of the charter. The

information is reported by aircraft type by month.

Part 234 Airline Service Quality Reports (14 CFR

234) requires 14 certificated U.S. air carriers (a carrier with more than 1 percent of total domestic

scheduled passenger revenues) to file monthly flight

performance information for every domestic nonstop scheduled passenger operation to or from the

27 largest U.S. airports (airports with more than I

percent of domestic scheduled passenger enplanements). Carriers are voluntarily reporting data for

each domestic scheduled flight instead of limiting

~Wi]liam D, Reynard, chief, Aviation Safety Reporting SYstem, Personal communciation, Feb. 23, 1988.

their reporting to the 27 airports. For the origin airport of each nonstop segment, the carrier reports

published departure times versus actual departure

times; for the destination airport, the published arrival times versus the actual arrival times are reported. This information is reported by date and

day. Flights delayed because of mechanical reasons,

as defined by FAA, are not reported.

Part 241 Uniform System of Accounts and

Reports for Large Certificated Air Carriers (14 CFR

241) prescribes the accounting and reporting regulations for large U.S. certificated air carriers (Section 401 certificate). A large carrier is defined as a

carrier operating aircraft which are designed to accommodate more than 60 seats or a cargo payload

of more than 18,000 pounds. All large carriers,

according to the level of their operations, as measured by annual operating revenues, are placed into

one of four groups: Group I Small ($10 million and

under), Group 11 Large ($10,000,001 to $75 million),

Group III ($75,000,001 to $200 million) and Group

IV (over $200 million), The amount and detail of

reporting increases with carrier size. Data are submitted on individual schedules of the DOT Form

41 Report or by electronic media. In general, carriers report exposure data such as aircraft departures,

hours, miles, and passenger enplanements in total

and by aircraft types. A broad range of financial

data including categories of revenues and expenses

are also reported, with those related to operations

being indexed by aircraft type.

Part 291 Domestic Cargo Transportation (14 CFR

291) prescribes the reporting required of carriers providing domestic all-cargo operations exclusively under Section 418 certificates. These carriers are required to file Form 291-A, a one page annual report,

which contains seven profit and loss items, and

seven traffic and capacity items. The data are not

reported by aircraft type.

Part 298 Exemptions for Air Taxi Operations (14

CFR 298) prescribes the reporting for small certificated air carriers (Section 401 certificate) and commuter air carriers. Both classes of carriers operate

aircraft which are designed for 60 seats or fewer or

for 18,000 pounds of cargo capacity or less. A commuter air carrier is defined as a special classification

of air taxi operator that provides passenger service

consisting of at least five roundtrips per week be-
87

tween two or more points. Commuters report only

traffic exposure data totals with no indexing by aircraft type. Small certificated air carriers submit the

same information as commuters plus revenue and

expense data. The direct expense data and three

operational items (block hours, departures, and gallons of fuel issued) are indexed by aircraft type on

small certificated air carrier reports. Air taxi operators which are not commuters have no reporting

Various reports including electronic submissions

are sent monthly, quarterly, semiannually, and annuall y to the Office of Aviation Information Management, where the data are entered into the Amdahl computer located in the DOT headquarters

building in Washington, DC. Most of these data

are published or loaded on magnetic tapes and are

available to the general public by subscription.

requirements.

CONCLUSIONS AND OPTIONS

No single measurement or statistic provides a complete picture of commercial aviation safety. While

accident and fatality statistics are the best measures

of long-term past risk in commercial aviation, they

are of limited value over short periods of time and

are not suitable monitors of short-term effects of policy decisions. For example, the consequences of recent rulings requiring collision avoidance systems

on commercial transports and transponders on

many general aviation aircraft may not be apparent in the accident data for 5 years or more.

Nonaccident safety data, while not substitutes for

accident and fatality data, are valuable supplements.

If properly collected and maintained, nonaccident

data can help identify and estimate the magnitude

of safety problems and permit the monitoring of

safety programs. OTA concludes that nonaccident

data must be used in short-term safety analyses.

FAA has made great strides in recent years in collecting and analyzing air traffic incident data. Indeed, OTA found FAA’s air traffic data to be the

most useful nonaccident indicators of system safety.

However, since the air traffic system is so safe, only

a fraction of the commercial aviation accidents and

fatalities are caused by the air traffic environment.

Consequently, additional nonaccident data are required for tracking changes in commercial aviation

safety. OTA finds that FAA programs to identify

and monitor changes in the commercial aviation

safety system need upgrading.

With the exception of airline inspection records,

sufficient data for better monitoring and assessing

of commercial aviation safety are collected by or are

available to Federal aviation authorities. However,

FAA quality control programs need improvement

to ensure accurate and consistent data collection and

reporting. For example, the FAA computer center

in Oklahoma City, which maintains most of the air

carrier-specific information, does not verify incoming data. Furthermore, most of the databases are

designed primarily for recordkeeping; this constrains,

but does not prohibit, analysis,

OTA found the analytical capabilities of both the

personnel and the data system at NTSB to be valuable resources. NTSB could readily provide published reports or customized computer printouts;

much of the accident data used in this study was

supplied by NTSB. OTA found that while both

NTSB and FAA maintain accident/incident air

carrier specific databases and are under tight staff

restrictions, the close coordination among NTSB

data system managers, analysts, and field person.

nel enables NTNB to use its data system effectively

for analysis in contrast to FAA’s system in Oklahoma City.

The FAA electronic systems required for processing the vast amount of data collected are adequate

storage media, but their flexibility and utility for

safety analysis vary widely. Experienced safety analysts, the eventual system users, took part in the design of the NASA ASRS and remain involved in

the processing and encoding of data. OTA found

ASRS data, along with FAA air traffic information, to be the most valuable incident data on commercial aviation that it reviewed. ASRS stands as

an excellent example of how to develop and manage an aviation safety data system. OTA found

that the close working relationship among data

86-680 - 88 - 4 : CL 3
88

managers and analysts allows ASRS to be used for

a wide range of accident prevention efforts. The

system could serve as a useful model for Aviation

Standards data systems, which were configured to

accept data from report forms poorly designed for

computer input. Additionally, the FAA computer

center staff, while knowledgeable about and competent in using the systems, are not trained analysts.

To compound problems, FAA management structure reflects the fragmented nature of the FAA data

systems. Three separate FAA organizations have

safety data responsibilities, and databases, data terminology, and automated systems are often incompatible within and among these organizations.

The few FAA studies that use nonaccident data

appropriately have come primarily from the Office

of Aviation Safety. Recent studies by this office focused on ATC system difficulties, such as near

midair collisions, air traffic controller errors, and

pilot deviations. On the other hand, the Office of

Aviation Safety has had little success in using the

AVS data systems and their air carrier information.

For example, the Office of Aviation Safety prepares

the Annual Report on the Effect of the Airline Deregulation Act on the Level of Air Safety, which

does not present or appropriately analyze available

nonaccident statistics. The effect of airline operating or management practices, or changes in

those practices, on commercial aviation safety are

rarely addressed in FAA studies. Air carrier-specific information systems, such as the Work Program

Management Subsystem and the Air Operator Data

System, are essential tools for properly trained field

office personnel in support of AVS’s commercial

aviation oversight role. OTA finds that improved

access to these databases is needed at regional and

field offices, a key consideration for future FAA information systems and enhancements currently being developed.

The advent of airline deregulation raised concerns

that economic pressures could force airline managements to cut back on safety practices. The Office

of Flight Standards, responsible for periodically inspecting all airlines to ensure regulatory compliance,

is the logical choice for resolving this issue, but needs

to collect and retain the necessary data. Consistent, centralized records on the number, extent,

and results of air carrier inspections are vital to

ensuring the efficacy of FAA’s safety function.

Four data areas (all used to varying degrees

throughout FAA) could provide warning signals for

directing FAA attention, and with further refinement, could allow quantified estimates of changes

in risk. They include:

. aicraft mechanical reliability, including unscheduled landings due to mechanical problems;

. airline operating practices, including aircraft

scheduling and flightcrew work and duty shifts;

. inspection results, including quality assessments

of airline practices and violation rates; and

• financial condition of airlines, and how that relates to any of the other safety indicators.

Airlines themselves keep crucial safety information and FAA could benefit from working more

closely with airline data. For example, many air carriers maintain large internal databases that could

be used to validate FAA databases. However, ensuring the confidentiality of the air carrier data is

critical. FAA could encourage improved air carrier reporting of sensitive safety data, such as incidents, by guaranteeing that no penalties will resuit from reported information and could

consider making nonreporting a violation. Additionally, access to airline computer systems, such

as maintenance management systems,37 could enhance FAA’s monitoring capabilities.

While airlines share safety information through

industry and government sponsored workshops,

committees, and forums, no formal, centralized industry process is in place for collecting and evaluating these data. The airlines, as a group, might

consider developing a data system to serve as a cooperative industry clearinghouse for safety-related

maintenance, training, and operating information.

The system could be established independently or

in conduction with FAA, and ideally would tap the

potential of the airlines’ extensive automated information systems.

OTA concludes that all current FAA data systerns could benefit from a thorough, coordinated,

agency-wide review, although enough shortcomings are known now to effect significant improvements in the system. Data managers, analysts, and

field personnel should be involved collectively in all

new data system development projects.

~70ne major airline recently provided the Federal Aviation Administration direct access to its computerized maintenance records.
89

Furthermore, OTA finds that an agency-wide, system safety management approach for data responsibility is needed, and that immediate coordination

of Aviation Standards, Air Traffic, and the Aviation Safety Office efforts could bring major benefits providing support of policy development and

planning, and permitting more focused allocation

of agency resources. The current fragmented approach creates inconsistencies, nonstandardization,

poor quality control, incompatible electronic systems, and insufficient data and data analyses. In the

long term, FAA could establish a consistent monitoring and analysis program to refine the selection

of safety indicators and the procedures for collecting and processing information. Safety management,

including data managing, is an iterative process.
Chapter 5

Safety Da a Anal

What Do We

ysis—

Know

Photo credit: Federal Aviation Administration

An FAA inspector observes an airline captain’s instrument flying technique.
CONTENTS

Accident Data . . . . . . . . . . . . . . . . .

Accidents and Fatalities . . . . . . .

Accident Causes and Types. . . .

Nonaccident Safety Data. . . . . . . .

Incident Data... . . . . . . . . . . . . . . .

Air Traffic Incidents . . . . . . . . . .

General Incidents. . . . . . . . . . . . .

Accident/Incident Causal Factors

Aircraft Capabilities . . . . . . . . . .

Personnel Capabilities. . . . . . . . .

Traffic Environment . . . . . . . . . .

Management Practices . . . . . . . . . .

Maintenance . . . . . . . . . . . . . . . . .

Operations . . . . . . . . . . . . . . . . . .

Page

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .102

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .103

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .103

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .105

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .105

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .105

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .106

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .108

Regional/Commuter Airline Operations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. ...109

Employee Selection and Training . . . . . . . . . . . . . . . . . . . . . . . . . . . ................110

Management Policies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ......................111

Conclusions and Policy Options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ............112

Figure

5-l. Passenger Fatality

5-2. Airline Accidents

Figures

Page

Rates for Part 121 Scheduled Airlines. . . . . . . . . . . . . . . . . . . . . 93

Initiated by Aircraft Equipment Failure . . . . . . . ........ . . . 96

5-3. Part 121 Accident Broad Causes and Factors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96

5-4. Air Carrier Near Midair Collisions (1975-87) ...... +... . . . . . . . . . . . . . . ......100

S-S. Operations Per Controller at Towers and Centers . . . . . . ....................102

5-6. Basic In-flight Shutdown Rate, B727/JT8D Engines . . . . . . . . . . . ..............104

5-7. Average Flight Equipment Maintenance Expense for B727-200 Fleet . .........107

Table

5-1. Commercial

5-2. Commercial

Aviation

Aviation

Accident

Accident

5-3.

5-4.

5*5.

5-6.

5-7.

Accident Categories . . . . . . . . .

Tables

Page

and Fatality Totals, 1975-1987 . . . . . . . . . . . . . . . 94

and Fatality Rates . . . . . +........ . . . . . . . . . . . 94

. . . . . . . . . . . . . . . . . . . .

Part 121 Fatal Accidents, 1975-86 . . . . . . . . . . . . . . . . .

Part 121 Total Accidents, 1982-1985 . . . . . . . . . . . . . . .

Commercial Aircraft Midair Collisions.. . . . . . . . . . . .

Qualifications of New-Hire Commercial Flight Crews

. . . . . . . . . . . . . . . . . . . . . . . 97

. . . . . . . . . . . . . . . . . . . . . . . 97

. . . . . . . . . . . . . . . . . . . . . . . 98

. . . . . . . . . . . . . . . . . . . . . . . 99

. . . . . . . . . . . . . . . . . . . . . . . 110
Chapter 5

Safety Data Analysis—What Do We Know

Data attest to the safety of commercial aviation;

statistics show that over the years the risk of injury

or death has steadily declined for airline passengers

(see figure 5-l). However, increased traffic congestion and new and different operating patterns have

placed unprecedented demands on the aviation system. Measuring recent changes in passenger risk is

difficult because accidents are infrequent and data

on other safety factors are not systematically collected or maintained (see chapter 4). OTA searched

government and industry databases for potential

safety indicators, and conducted case studies and

surveys of airline management, pilots, and mechanics. The results of these efforts are presented in this

chapter. Tasked with assessing commercial aviation

safety, OTA focused primarily on Part 1211 airlines, which carry about 95 percent of the passengers and account for 99 percent of the passengermiles. However, Part 135 commuter airlines are responsible for the safety of a significant number of

people–over 18 million passengers in 1986–and

their operations are discussed as well.

IA1~]i~~ ~P~~~tiOns With alrp]anes having more than 30 seats or PaYIoad capacity greater than 7,500 pounds are certificated under 14 CFR

121. Alrllnes flylng smaller airplanes are governed by 14 CFR 135, or

if they choose, the more demanding 14 CFR 121.

Figure 5-1 .—Passenger Fatality Rates for

Part 121 Scheduled Airlines

o

5

4

3 i

I h

Year

SOURCE: Office of Technology Assessment based on data compiled from the

Civil Aeronautics Board, Federal Aviation Administration, and National Transportation Safety Board.

ACCIDENT DATA

Accidents and Fatalities

Airline passenger risk is not gauged solely by numbers of fatalities; rather, passenger injury or fatality

rates and the rate at which flights end in accidents

or crashes are considered the best indicators of past

risk. Statistical comparisons for commercial aviation

are skewed by differences in aircraft size and in flight

distances. For example, since the mid-1970s, Part

121 airline operators have had the fewest fatal accidents; however, because each plane carries many

passengers, these operators have had the most passenger fatalities in commercial operations (see table

5-1). To complicate analysis further, over 70 percent

of jetliner accidents occur during takeoff, initial

climb, final approach, or landing, but these represent only 6 percent of the flight time and even less

of the mileage.2 Therefore, departure information

for aircraft and passengers is necessary to estimate

risk, and other exposure data do not permit appropriate comparison among the aviation categories.

(See chapter 4 for further discussion.)

Although accident data are considered generally

accurate and complete, exposure data quality varies

with the aviation segment. While most scheduled

Part 121 carriers must report extensive traffic data

under U.S. Department of Transportation (DOT)

requirements, smaller charter, commuter, and air

~Boeing Commercial Airplane Co., Statistical Summary of Commercial]et Aircrafi Accidents: Wor]dtl.ide -rations 1959& (Seattle, WA:

April 1987).

93
94

Table 5-1.–Commerciai Aviation Accident and Fataiity Totals, 1975-87

Part 121 Part 121 Part 135 Part 135

(scheduled) (nonscheduled) (scheduled) (nonscheduled)

Accidents . . . . . . . . 269 50 446 1,918

Fatal accidents. . . . 37 11 109 435

Fatalities . . . . . . . . . 1,393 668 431 1,086

SOURCE: Office of Technology Assessment based on National Transportation Safety Board January 198S data.

taxi airlines need report little or none. DOT publishes estimates of all Part 121 and scheduled Part

135 aircraft departures and of all Part 121 passengers carried; these data are used in this chapter.

However, OTA had to derive commuter passenger

statistics from data collected by the Regional Airline Association (RAA), and estimated air taxi

passenger and departure figures from information

supplied by the National Air Transportation Association. Due to inherent inaccuracies in these data,

the estimates have limited utility for trend analyses, but they are valid approximations of exposure

magnitude.

Tablke 5-2.—Commerciai Aviation

Aircraft departures and passenger enplanements3

are incorporated into the accident and fatality rates

shown in table 5-2. These data show no significant

‘Passenger departures would be a better choice here, but the data

are not available. Passenger enplanements, or the number of people

who board flights, are recorded. Passenger departures equal passenger

enplanements on nonstop flights, but are greater on multistop flights.

Fatalities per passenger-carried is one statistical method to normalize the fatality rates among the various industry segments, and offers

a sound comparison tool. Fatalities per aircraft-departure, -hour, or

-mile would be skewed by aircraft size and range. Since each fatality

is not an indepmdent event, these statistics must be used with caution. The three types of risk measurements presented should be considered together.

Accident and Fatality Rates

Part 121 Part 121 Part 135a Part 135b

Year (scheduled) (nonscheduled) (scheduled) (nonscheduled)

Accidents per million departures:

75-77 . . . . . . . . . . . . . . 4.8 53 27 58

78-80 . . . . . . . . . . . . . . 3.7 39 27 54

81-83 . . . . . . . . . . . . . . 4.1 18 12 55

84-86 . . . . . . . . . . . . . . 2.8 22 8 53

87 . . . . . . . . . . . . . . . . 4.3 23 14 38

75-87 . . . . . . . . . . . . 3.8 30 17 54

Fatal accidents per million departures:

75-77 . . . . . . . . . . . . . . 0.48 10.6 11

78-80 . . . . . . . . . . . . . . 0.57 6.5 U 13

81-83 . . . . . . . . . . . . . . 0.72 2.6 2.6 13

84-86 . . . . . . . . . . . . . . 0.34 8.0 2.1 11

87 . . . . . . . . . . . . . . . . 0.43 4.6 4.1 12

75-87 . . . . . . . . . . . . 0.51 6.5 4.1 12

Fatalities per million passengers-enplaned:c

75-77 . . . . . . . . . . . . . . 0.34 24.2 3.4 14

78-80 . . . . . . . . . . . . . . 0.56 0.2 4.4 13

81-83 . . . . . . . . . . . . . . 0.26 0.1 1.5 11

84-86 . . . . . . . . . . . . . . 0.17 14.7 1.6 9

87 . . . . . . . . . . . . . . . . 0.41 0.1 2.8 10

75-87 . . . . . . . . . . . . 0,33 9.1 2.6 12

aschedt.jled part 135 passenger counts estimated by OTA based on Regional Airline Association databNonschedulad pan 135 passenger and departure data estimated by OTA baaed on National Air Transportation Association

and other air taxi data.

COTA calculations based on National Transportation Safety Board and Federal Avlatlon Adminlstratlon data. All 1~7 rates

based on estimated passenger-anplanement data.

SOURCE: Office of Technology Assessment based on National Transportation Safety Board data as of January 19S8, unless

otherwise noted.
95

increase in past passenger risk since the enactment

of the Airline Deregulation Act. Indeed, 1984 to

1986 was the safest 3-year period for the large scheduled airlines, and commuter lines improved their

safety record substantially, although the downward

accident trend faltered in 1987. The inaccuracy of

the exposure data limits conclusions regarding safety

trends for nonscheduled airlines; however, it appears

that air taxi safety remained unchanged.

The relative infrequency of Part 121 charter operations and accidents makes trend analyses for that

part of commercial aviation very difficult. Accident

rates for scheduled Part 121 and 135 airlines in 198’7

were higher than in recent years,q although fatality and accident statistical trends for a single year

must be viewed with caution. Since commercial aviation accidents are relatively rare, a single crash of a

large jet can skew the statistics.

Large aircraft fatal accidents usually result in either few fatalities or few survivors. From 1975 to

1986, only 17 Part 121 accidents with 10 or more

fatalities occurred, and of those accidents, 7 accounted for over 70 percent of the fatalities. 

Industry segments have distinctly different accident rates. For example, scheduled Part 121 airlines

have significantly better records than other types

of air transportation. In contrast, nonscheduled 121

airlines provide less than 3 percent of the Part 121

departures and passengers, but account for 23 percent of the fatal accidents and 32 percent of the fatalities.

Commuter airlines have accident and fatality rates

3 to 10 times above those of the large scheduled airlines. These disparate levels of safety often reflect

differences in safety regulations, equipment, and

operating environments. For example, commuters

may have less advanced technologies or lower training levels than major airlines because they have

fewer aircraft in their fleets and fewer passengers per

flight to distribute the costs involved. The largest

commuter airlines have the best safety records; indeed the 20 largest Part 135 commuters (and Part

121 regionals) have safety records similar to those

qNatlonal Tran~portation Safety Board data released Jan. 13, 1988.

of jet carriers. 5 Aircraft type and airport characteristics have little influence on the safety record.6

Accident Causes and Types

The primary purpose of accident investigations

is to determine the probable causes of transportation accidents and to recommend preventive measures. Because most accidents involve a complex congruence of multiple events and causes, aviation

accidents do not lend themselves to simple classification or categorizing by type or cause. Moreover,

accidents of the same type often require several

different preventive measures, although single solutions can sometimes reduce the occurrence rate

of a wide range of accidents. For example, ground

proximity warning devices reduced markedly the

rate of controlled flight into terrain accidents for

jetliners (see chapter 7).

The National Transportation Safety Board (NTSB)

currently classifies accidents by a variety of methods, such as causes and factors, sequence of events,

and phase of operation. Determining up to five distinct occurrences in the chain of events leading to

an accident, NTSB categorizes the accident by the

first occurrence. While events such as aircraft component failures and encounters with weather are

prominent in first occurrences, human errors are

harder to trace from the data. 7

OTA completed a trend analysis of aircraft component failure as a first occurrence in airline accidents (see figure 5-2). The analysis showed no significant change in the rate for Part 121 carriers and

noticeable improvements by the Part 135 commuters

during the past decade. Therefore, any recent

changes in Part 121 airline maintenance practices

appear not to have affected aircraft mechanical reliability in a way that results in more accidents. Data

on other common first occurrences, such as encounters with weather or collisions with objects or terrain, cover too broad a range of accident circumstances to provide meaningful trends.

5c}inton v. Oster, Jr. an d C. Kurt Zorn, “Airline Deregulation,

Commuter Safety, and Regional Air Transportation, ” Growrrh and

Change, vol. 14, July 1983, pp. 3-11.

‘Ibid.

‘Stan Smith, accident data chief, National Transportation Safety

Board, personal communication, May 15, 1987.
96

Figure 5-2.–Airline Accidents Initiated by

Aircraft Equipment Failure

1

0

75-77 7&80 81-83 04-35

Years

_ TotaI Part 121 ~ Scheduled Part 135

SOURCE: Office of Technology Assessment from National Transportation Safety Board findings of the “firat occurrence” in the sequence of events

leading to the accidents, 1975-1985.

Accident causal data usually imply corrective actions, but since accidents frequently have multiple

causes, developing causal categories is difficult. In

most cases, each cause is independent of the others,

and if one did not exist, the accident might not have

occurred. However, analyzing the multiple causes

of accidents does highlight the relative prevalence

and trends of certain factors. Figure 5-3 shows that

while weather- and personnel-related (nonpilot)

causal rates for Part 121 accidents diminished prior

to deregulation, pilot error and aircraft-related causal

rates have changed little.

Figure 5-3.— Part 121 Accident Broad

Causes and Factors

75-7 7 78-8 0 81-83 84-35

Year Group

m Pilot m PersonneI El Weather Ml Aircraft

SOURCE: Office of Technology Assessment based on National Transportation

Safety Board data.

cause, 8 and OTA found that at least 40 percent of

Part 121 fatal accidents could not be adequately accounted for by single causes.

Each of these analysis types thus has shortcomings for understanding the complexity of individual accidents. As an alternate method, OTA identified the two most significant sequential causal

events in each accident.9 After reviewing NTSB

Part 121 accident briefs, OTA classified all fatal Part

121 accidents from 1975 to 1986 and total Part 121

accidents from 1982 to 1985 according to the classification scheme shown in table 5-3.1

° The relative

Boeing, the Flight Safety Foundation, and others

have categorized accidents by primary cause. This

method gives a clear cross section of accident events

and allows accident classification. However, determining which of the multiple causes is the most important is a subjective process. One analysis of major accidents involving large jet transports worldwide

found that only 28 percent had a single probable

8Richard L. Sears, “A New Look at Accident Contributors and the

Implications of Operational and Training Procedures,” Znfluence of

Training, Operational and Maintenance Practices on Flight Safety,

Proceedings of the Flight Safety Foundation’s 38th Annual International Air Safety Seminar (Arlington, VA: Flight Safety Foundation,

NOV. 4-7, 1985), pp. 29-51.

9

For a variation of this method, see Clinton V. Oster, Jr. and C.

Kurt Zorn, Transportation Research Center, Indiana University, “Improving Military Charter Safety,” unpublished manuscript, November

1987,

‘“Other causal categories are possible, but were not necessary for

Part 121 accidents OTA reviewed.
97

Table 5-3.—Accident Categories

1. Collisions

A. Controlled flight

1. Pilot error, then flight path deviation

2. Pilot error, then aircraft component failure

3. Personnel error, then flight path deviation

4. Personnel error, then aircraft component failure

5. Aircraft component failure

6. Miscellaneousa

B. Uncontrolled flight

1. Pilot error, then aircraft component failure

2. Pilot error, then encounter with weather

3. Pilot error, then flight path deviation

4. Personnel error, then aircraft component failure

5. Personnel error, then weather

6. Aircraft component failure, then pilot error

7. Encounter with weather, then aircraft component

failure

8. Aircraft component failure

9. Encounter with weather

10. Miscellaneousa

Il. No collision

A. Controlled flight

1. Pilot error

2. Personnel error

3. Aircraft component failure

4. Miscellaneous

%TA classified midair collisions under the miscellaneous category. While a

midair could fit possibly into any of the collision categories above, midairs are

distinct enough to warrant a separate classification, but are too rare to call for

a special category.

SOURCE: Office of Technology Assessment, 1988.

prevalence of accidents according to causal factors

is presented in tables 5-4 and 5-5—approximately

60 percent of the fatal accidents by scheduled passenger carriers are initiated by human error, and

human error is a causal factor in over 70 percent

of these accidents. Aircraft component failure, severe weather, and miscellaneous causes initiated the

remaining accidents.

However, when nonfatal accidents are included,

the influence of mechanical failure doubles; it is the

enabling cause in over 30 percent of all accidents

and is involved in almost 50 percent. 1l Additionally, noncollision accidents, which are rarely fatal,

result primarily from aircraft component failures.

Two fatal noncollision accidents occurred between

1975 and 1986, as compared to 9 nonfatal noncollision accidents between 1982 and 1985; all of these

accidents involved aircraft component failures.

1 IThe failure of an aircraft component, such as landing gear, maY

cause substantial damage to the aircraft but not subject the passengers

to harm. See “accident” definition, box 4-A, ch. 4.

Table 5-4.–Part 121 Fatal Accidents, 1975-86

Scheduled Scheduled Nonscheduled Nonscheduled Totala

passenger cargo passenger cargo Total (by percent)

Initiating causal factor:

Pilot . . . . . . . . . . . . . . . . . . . . . . . . .

Personnel . . . . . . . . . . . . . . . . . . . .

Aircraft . . . . . . . . . . . . . . . . . . . . . . .

Weather . . . . . . . . . . . . . . . . . . . . . .

Miscellaneous. . . . . . . . . . . . . . . . .

All causal factors:g

Pilot . . . . . . . . . . . . . . . . . . . . . . . . .

Personnel . . . . . . . . . . . . . . . . . . . .

Aircraft. . . . . . . . . . . . . . . . . . . . . . .

Weather . . . . . . . . . . . . . . . . . . . . . .

Miscellaneous. . . . . . . . . . . . . . . . .

Total accidents. . . . . . . . . . . . . .

10

3

b

4

3

2

e

13

3

6

8

2

22

1

1

C

1

0

0

2

1

1

0

0

3

1

l

d

1

0

0

3

0

3

0

1

f

3

0

4

0

1

7

15

5

9

3

3

20

5

12

9

3

35

57

14

34

26

9

NOTE: Accidents involving weather turbulence, sabotage, or nonoperational events, such as ramp activities, are not included.

%itiating causal factors may not total 100 percent due to rounding. For all causal factors, numbers do not total 100 percent because most accidents involve multiple causes.

%WO accidents involving air traffic control personnel and one involving maintenance personnel.

cAccident involved air traffic control personnel.

dGround collision caused by other Pilot.

%WO midair collisions, including Aeromexico DC-9/PA 28-181 over Cerritos, CA, Aug. 31, 1988.

fln.flight collision with parachutist.

gAll cauaal factors includes Up to two significant causes in the sequence of events leading to the accident.

SOURCE: Office of Technology Assessment based on National Transportation Safety Board data as of January 1988.
98

Table 5-5.–Part 121 Total Accidents, 1982-85

Scheduled Scheduled Nonscheduled Nonscheduled Total a

passenger cargo passenger cargo Total (by percent)

All causal factors:e

PiIot . . . . . . . . . . . . . . . . . . . . . . . . . 16 6 2 3

Personnel . . . . . . . . . . . . . . . . . . . . 3 0 0 1

Aircraft . . . . . . . . . . . . . . . . . . . . . . . 16 1 2 4

Weather . . . . . . . . . . . . . . . . . . . . . . 8 2 1 0

Miscellaneous . . . . . . . . . . . . . . . . . 3 0 0 0

Total accidents . . . . . . . . . . . . . . 34 6 3 7

NOTE: Accidents involving weather turbulence, sabotage, or nonoperational events are not included. aFOra[l Causal factors, numbersdo nOttOtd 100 Percent.

bTwo accidents involving air traffic control personnel and one involving maintenance personnel

cAccident involved maintenance personnel.

dTwoco~isions with birds and one collision whHet=fln9.

eA[l causal factors includes “p to two significant causes in the sequenceof events leading to the accident.

SOURCE: Office of Technology Assessment based on National Transportation Safety Board data as of January 1988.

NONACCIDENT SAFETY DATA

Since aviation accidents are so infrequent, trends

observed over 1 or 2 years of accident data may not

be meaningful or indicate actual changes in risk. Despite the long-term improvement in aviation safety,

recent concern over near midair collisions (NMACs)

and airline operations suggests an interest in more

timely information on changes in aviation safety.

The Federal Aviation Administration (FAA) currently collects many types of nonaccident safety

data, such as information on air carrier operations

and incidents, but data quality and system limitations prevent analysis of all but a few years of air

traffic safety data.

Database validity is the key problem in nonaccident safety data analyses. While aircraft accidents

leave permanent evidence, many nonaccident safety

events (such as NMACs) are transitory, and some

go unrecognized, while others are inaccurately observed. Moreover, even when an event is observed

and recognized correctly, it may not be reported for

a number of reasons, including misunderstanding

23

4

18

2

3

27

4

23

11

3

50

46

8

36

4

6

54

8

46

22

6

of the reporting process, apathy, and fear of repercussions. Current FAA practices present the reporter with many personal risks, including prosecution

for Federal Aviation Regulations (FARs) violations,

employer sanctions, and time lost for the administrative process.l2

Nonaccident data analyses have multiple purposes

—while isolated reports of safety events can identify the existence of a problem, data must be collected broadly and consistently to estimate reliably

the extent of the problem. Moreover, complete and

accurate data are required for understanding the

causes of problems and for developing countermeasures. Data system management is the final hurdle

for nonaccident data utility. Incoming reports must

be properly handled and consistently organized, and

the resulting databases must be accessible to analysts.

‘

) For these reasons, the Federal Aviation Administration grants immunity and guarantees anonymity to reporters who use the Aviation

Safety Reporting System, which is administered by the National Aeronautics and Space Administration.

INCIDENT DATA

Every accident begins as an incident, and incidents (NASA), NTSB, and FAA databases. Thus aviation

are reported much more frequently than accidents incidents, or ‘(near accidents, ” are good substitutes

to National Aeronautics and Space Administration for sparse accident data. Additionally, more infor-
99

mation, especially regarding human performance

causal factors, is often available from them for safety

investigators, since incidents do not result in fatalities or serious damage.

However, incident data are difficult to collect reliably, primarily because of the imprecise definition for

aviation incidents. NTSB considers an “incident”

to be ‘(

. . . an occurrence other than an accident,

associated with the operation of an aircraft which

affects or could affect the safety of operations.”13

For specific incident types—an in-flight fire, for example—better criteria are used. If collected and analyzed separately, these specifics offer valuable information on safety.

As the ratio of incidents to accidents varies by

accident/incident category, trends in total incidents

can be misleading. For example, a rise in a widespread, but low-risk incident type and a decrease

in an infrequent, but high-risk incident type results

in an increase in the total incident rate, although

overall risk may be reduced. Analyses by specific

accident/incident type avoids this confusion.

Air Traffic Incidents

Air traffic incidents, such as NMACs, runway incursions, and operational errors, reflect aspects of

air traffic system14 safety. For the most part, analyses of these data address aircraft classes, such as

air carrier or general aviation (GA), and airspace

categories—Terminal Control Areas, for example.

Air traffic incidents are defined more clearly than

general incidents and are reported primarily by air

traffic controllers and pilots.

Near Midair Collisions

An in-flight collision involving a passenger transport is among the most feared of aviation accidents.

While such collisions are rare events (see table 5-6),

they account for roughly 10 percent of fatalities. Statistics indicate a very low risk with no discernible

trends in these accidents, but annual increases in

the reported number of NMACs have created

concern.

“49 CFR 830.2 (Oct. 1, 1987).

l+The “air traffic system” includes all flight operations, not only

those under air traffic control.

Table 5-6.—Commercial Aircraft Midair Collisions

Part 121 Part 135 Part 135

(total) (scheduled) (nonscheduled)

1975-1977 . . . . . . . . 0 2 4

1978-1980 . . . . . . . . 1 0 9

1981 -1983 . . . . . . . . 0 2 8

1984 -1986 . . . . . . . . 0

a 1 2

1987 . . . . . . . . . . . . 0 1 2

aA ~idal~ ~Olli~iO~ ~twmn an AerOrnexiCO Deg and a private PA 2&181 occurred

over Cerritos, CA on Aug. 31, 1988.

SOURCE: Office of Technology Assessment based on National Transportation

Safety Board data as of January 1988

FAA and NASA collect data on NMACs independently, but both agencies rely on voluntary

reports. FAA investigates each report and can

impose penalties if regulations were violated. In contrast, NASA maintains the anonymity of the reporter and FAA guarantees immunity from potential penalties that could result from the event. FAA

has cited its own mismanagement of NMAC report

paperwork, as well as changes in public perception

and awareness, as reasons for not using the FAA

NMAC database for trend analysis. FAA corrected

its report processing problems in 1985, 15 a n d

claims that recent increases in NMAC rates more

closely reflect reality.l6

OTA finds that substantial evidence points to

analytically valid subsets of NMAC data. FAA recovered many missing 1983 and 1984 NMAC reports, and FAA and NASA databases show similar trends from 1981 to the present; moreover,

NASA data were not subject to management problems during this period. However, this does not preclude changes in pilot (the primary reporters of

NMACs) perception from influencing both sets of

data.

Air carrier pilots are a relatively homogeneous

group who are very aware of incident reporting procedures and may thus be more likely than GA pilots to report an observed NMAC. Moreover, air

carrier pilots fly primarily under instrument flight

rules (IFR) and, if involved in an NMAC, would

15Burt Solomon, “FAA Runs Into Some Heavy Turbulence in Aviation’s Worst Year for Fatalities, ” IVarlonal]ournal, Oct. 12, 1986, pp.

2313-2316.

l~Dona]d Engen, administrator, Federal Aviation Admmlstratlon,

“Aviation Safety (Near Midair Collisions and Runway Incursions),”

testimony before U.S. Congress, House Committee on Public Works

and Transportation, Subcommittee on Investigations and Oversight,

Apr. 9, 1987, p. 66.
100

be in communication with air traffic control (ATC).

For reporting purposes, aircraft involved in NMACs

are grouped into three categories: air carrier (Part

121 or 135 operators), GA, and military. Air carrier and GA aircraft are involved in over 95 percent of the reported NMACS.

17

The FAA Office of Aviation Safety found that

less than 20 percent of air carrier/GA and military/GA incidents are reported by the GA operators involved.18 In a comparative analysis of FAA

and NASA NMAC reports, OTA found that about

18 percent of the air carrier-involved NMAC reports

in the FAA database show up in the NASA data,

as contrasted to less than 10 percent of all FAA

NMAC reports. Air carrier NMAC data are more

consistent than the other subsets of the data, including the total.

Theoretically, the NMAC rate (and the actual collision rate) is proportional to traffic density raised

to some power.19 Since traffic density data are not

readily available, OTA used aircraft operations

(takeoffs and landings) at towered airports as a substitute. OTA found that the annual number of air

carrier operations and the annual number of reported air carrier-involved NMACs fit a nonlinear

model well, as shown in figure 5-4. Despite the implication that increases in air carrier traffic will result in higher numbers of air carrier NMACs, accident data do not bear out a correlation between

increasing frequency of reported NMACs and increasing risk of collision. The sparseness of the collision data prohibit determining valid trends; we simply cannot tell with current information.20

Runway Incursions

A collision between two airliners on a runway can

be just as devastating as a collision in the air; the

17U s Department of Transp~ation, Federal Aviation Adminis-

. .

tration, “Selected Statistics Concerning Pilot Reported Near Mid-Air

Collisions (1983 -85),” June 1986, p. A2-1.

*81bid, p. 8 l~e near midair collision risk is proportional to the number of Ptential conflict pairs of aircraft (approximately the number squared)

per area for a two dimensional, random flight path model. See Walton Graham, Questek, Inc., “Technology Requirements as Derived

From Accident Rate Analysis,” AIAA.80-0918 (Washington, DC:

American Institute of Aeronautics and Astronautics, May 1980).

Zme Federa] Aviation Administration’s ~ce of Aviation SafetY’s

Safety Analysis Division has several studies underway of near midair

collisions by airport and airspace location.

500

400

200

1(%)

o

Figure 5=4.—Air Carrier Near Midair

Collisions (1975-87)

o 13 15 17 19 21

Air carder operations at Federal Aviation

Administration towers (millions)

SOURCE: Office of Technology Assessment based on Federal Aviation Administration data.

greatest loss of life in aviation resulted from such

an accident involving two B-747s in Tenerife in

1977. Near collisions on the ground raise many of

the same concerns as near collisions in the air.

Currently, runway incursions (see definition in

chapter 4) as well as other ground incidents caused

by an air traffic controller’s actions are reported as

“operational errors, “ and when the pilot is at fault,

the event is reported as a “pilot deviation. ” Additionally, some runway incursion reports end up in

the NMAC database.21 Because FAA has not systematically collected data or published analyses on

runway incursions and does not maintain a separate runway incursion database (although it plans

to establish one),22 information on runway incursions must be extracted from these other databases,

which have been maintained in their current form

only since 1985.

ZIBrian Pmle, Federal Aviation Administration, mice of Aviation

Safety, personal communication, Jan. 21, 1988.

22 Ken Chin, Federal Aviation Administration, Office of Aviation

Safety, personal communication, Nov. 3, 1987.
101

While most runway incursions are probably observed by the controllers or pilots involved, an

NTSB special investigation found that the data are

not complete and are difficult to use effectively .2]

NTSB uncovered several runway incursions, classified as operational errors or pilot deviations, that

controllers did not formally report.24 FAA’s Air

Traffic Evaluations and Analysis Division reviews

all operational error reports and has established a

task group to study surface incidents, and the Office of Aviation Safety tracks statistics regarding surface deviations by pilots.

NASA collects runway “transgression” data

through Aviation Safety Reporting System (ASRS)

reports. Runway transgressions are defined as any

erroneous occupation of a runway at a controlled

airport by an aircraft or other controlled vehicle.

Traffic growth resulting in more reported NMACs

may have a similar influence on surface problems;

indeed, runway transgressions show similar trends

to those of NASA and FAA NMAC reports. However, while transgressions have been increasing, the

conflicts (or near collisions) resulting from them have

not increased since 1984, according to ASRS data.

Operational Errors and Deviations

Since 1985, FAA has maintained an automated

database of operational errors and operational deviations. Simply phrased, these incidents are occurrences attributed to ATC operations that result in

improper separation between an aircraft and another

aircraft, terrain, or obstacles (operational error) or

infringement upon protected airspace by an aircraft

(operational deviation). (See chapter 4 for complete

definitions.)

The quality of operational error/deviation data

varies by subset. Operational error/deviation data

are categorized by type of ATC facilities—terminals25 and en route centers. For centers, operational

errors and deviations are tracked automatically by

the Operational Error Detection Program, while error information at terminals comes primarily from

reports initiated by the personnel directly involved

‘~ National Transportation Safety Board, Special Investigation

Report-Runwa y Incursions at Controlled Airports in the United

Stares, NTSB/SIR-86/01 (Washington, DC: May 6, 1986).

241bid.

‘~erminals are the facilities, such as towers and approach controls,

that provide alr traffic control services at airports.

in the incident. (At en route centers, 57 percent of

errors and deviations are reported by automatic systems, as compared to 10 percent at terminals. Not

surprisingly, the reported error/deviation rate at

centers was nearly four times greater than at terminals, yet terminals handle about twice the number

of aircraft.)26 Consequently, many aspects of operational errors/deviations can be more accurately

analyzed when the data are grouped by ATC facility.

Without the aid of significant technological developments (see chapter 7), air traffic controllers

faced increasing workloads throughout the past decade. The average number of flight operations handled by each controller27 in recent years is higher

than for any period except the one immediately following the controller’s strike in August 1981,28 as

illustrated in figure 5-5. (Actual workloads vary considerably at individual centers and terminals.)29

The FAA Office of Aviation Safety has analyzed

in detail the 1985 and 1986 data. The precise relationship between growing traffic levels and error

rates is not clear. Overall traffic and controller workload have increased since 1985, and reported controller errors declined from 1985 to 1986, and then

increased at half the rate of the traffic growth in

1987. FAA investigated error/deviation rates for a

given year at facilities with varying traffic loads. For

center data (the most reliable), there are no welldefined relationships between error/deviation rates

and the average annual workload per controller or

the number of operations at the regional or individual facility level.30 For terminal data, no correlation was found at the individual facility level,

though some was observed on a regional basis.

Higher error/deviation rates occurred for terminals

in regions with the lower controller workloads.3l

2b1bid, p. 3-7.

*’For this analysis, a “controller” is a Federal Aviation Administration employee who directs air traffic. Full performance level controllers,

qualified on all air traffic control positions in a tower or center, and

developmental controllers, qualified on at least one position, are included.

28For the latter half of 1981 and much of 1982, some military air

traffic controllers were assigned to centers and towers.

‘qU.S. Department of Transportation, Federal Aviation Administration, Proh”le of Operational Errors and Deviations in the U.S. Air

Trafl?c System, Calendar Year 1985 (Washington, DC: May 1986), pp.

3-55 and 3-58.

~OIbid, p. 3-53.

311bid, p. 3-53.
102

197576 77 78 79 80 81 82 83 84 85 86

Year

~ Towers + Centers

NOTE: 1981 rates are distorted due to the walkout and subsequent dismissal

of controllers.

SOURCE: Office of Technology Assessment based on Federal Aviation Administration data.

The causal categories for operational errors and

deviations are human error, equipment problem,

and faulty procedure;32 human error was involved

98 percent of the time. FAA examined controller

experience as a factor in the human error-caused

incidents, and found that center controllers with

6 to 8 years of full performance level experience had

by far the highest error/deviation rate in 1985, more

than seven times greater than other controllers.

(Similar data are not available for terminals. )33

FAA has not conducted a similar analysis of 1986

or 1987 data.

In summary, the only conclusion that can be

drawn from current operational error/deviation data

is that no drastic deterioration in ATC safety has

occurred. Consistent data over a longer timeframe

and additional analysis could shed light on the correlation among incident rates, traffic levels, and controller workload.

General Incidents

Although FAA has improved its collection and

analyses of ATC incidents since 1985, the agency

gives scant attention to other air carrier and GA

incidents. Aviation Standards manages the reporting process for these incidents, and maintains them

in its Accident/Incident Data System (AIDS). However, AIDS has limited analytical capabilities, and

the data, as currently processed, have little value

as accident data surrogates.

AIDS was established primarily for administrative purposes; FAA cannot ensure easily that airlines report incidents accurately and consistently,

and does not make certain that its investigators process the information properly. OTA compared the

distribution of incident reports by FAA region to

the accidents that occurred in each for the period

1980 to 1985. For this analysis, OTA assumed that

geography did not substantially influence the distribution of incident types (the ratio of incidents to

accidents depends upon incident type). For the separate categories of air taxis, commuters, and Part

121 carriers, OTA found large regional biases for

the ratio of total incidents to total accidents, varying from 78 to 1 to less than 1 to 2. For example,

7 percent of the Part 121 accidents and only 1 percent of the incidents occurred in the Alaska Region,

while in the Great Lakes Region, 18 percent of the

accidents and 33 percent of the incidents happened.

Most of OTA’s sources, inside and outside of

FAA, familiar with this incident database believed

that it is not valid for analytical purposes. OTA’s

review of the database and data system confirm that

the data should not be used for measuring changes

in aviation safety. However, DOT’s annual report

to Congress pursuant to the Airline Deregulation

Act,34 as well as some journalists, have used AIDS

incident trends in published analyses.

The Aviation Safety Reporting System offers an

alternate source of incident information. Since

reports are made voluntarily, and many pilots do

not know of the existence of ASRS, it is difficult

to determine the validity of trends in the data over

time, although ASRS can provide insight into the

‘*Ibid, p. 3-68.

‘

]

Ibid, p. 3-100.

“U.S. Department of Transportation, Annual Report on the Effi.t

of the Airline Deregulation Act on the Level of Air Safety (Washington, DC: February 1987).
103

underlying causes of incidents, especially the role

of human factors. Consequently, while ASRS analyses can recommend preventive measures for certain classes of incidents, they cannot conclusively

determine the rate of incident occurrences. However, ASRS offers supplemental information to other

databases on trends and distribution of incidents

such as NMACs and runway incursions. Moreover,

unlike AIDS, the ASRS reporting format is designed

to facilitate computer entry and analysis, the data

are reviewed and encoded by experienced analysts,

and numerous quality control procedures are used

to ensure proper data processing.

OTA examined the relative prevalence of categories of ASRS incidents and compared them to accident data. NASA categorizes incidents by “primary problem, ” a classification quite similar to the

“primary cause factor” used by Boeing in accident

groupings. ASRS data indicate that from 1981

through 1986, the flight crew was the source of the

primary problem in 69 percent of the air carrier incidents. Boeing’s summary of worldwide commercial jet accidents from 1976 to 1986 also shows flight

crew error as the primary cause in about 65 percent

of the accidents.35 Other categories do not- match

quite as well. ASRS data cite the aircraft and

ATC/airports as the problem in about 6 percent

and 22 percent of the reports respectively, while Boeing’s analyses indicate that the aircraft accounts for

18 percent of the accidents and ATC/airports cause

less than 5 percent. Such differences illustrate the

errors that can be made in using the number or percent of incident reports to prove a point; nonetheless the incident reports are valuable analytic tools.

15The National Transportation Safety Board’s broad statistics cannot be used here as easily. Since multiple causes and factors are published instead of a single primary cause for each accident, Awation

Safety Reporting System and National Transportation Safety Board

data cannot be compared by percentage.

ACCIDENT/INCIDENT CAUSAL FACTORS

The primary causal factors (see chapter 4) of accidents and incidents are aircraft capabilities, personnel capabilities, traffic environment, weather,

and random events. However, all of these factors

are not amenable to trend analyses. For example,

while weather is a key factor in aviation safety,

weather-related accidents usually stem from insufficient weather information or errors in human judgment. Most would agree that a serious degradation

of aircraft, personnel, or traffic system capabilities

would likely result in a decrease in safety and a need

to develop countermeasures. Therefore, changes in

these three causal areas offer early warnings for Federal and industry safety attention.

Aircraft Capabilities

Commercial aircraft36 are designed and maintained to extraordinary standards, with multiple

redundancies and wide operating margins. Although

their components occasionally fail, few of the failures

‘Transport category airplanes (see 14 CFR 25), such as the jetliners

common to the major air carriers, are the only ones explicitly considered In this section. Aircraft certificated under 14 CFR 23, SFAR 23,

and SFAR 41, such as those used by commuter and regional airlines,

were not addressed.

become serious accidents, and most component

failures, even some that result in accidents, have a

small direct impact on passenger safety. Indeed, most

component failure accidents involve no collisions

or crashes, and few fatalities. Aircraft component

failure initiates 35 percent of the total accidents by

Part 121 scheduled passenger carriers, but just 18

percent of the fatal accidents. Moreover, of the passenger airline fatal accidents initiated by component

failures between 1975 and 1986, only one involved

an airplane that had become unflyable.37 Flight

crew capabilities played a major role in the other

accidents. On the other hand, each component failure indirectly affects safety—from distracting the

flight crew to limiting the airworthiness of the

aircraft.

FAA, airlines, and manufacturers collect detailed

data on the mechanical reliability of commercial aircraft, and the databases show many improving, and

few adverse, trends in aircraft reliability. Because

of close monitoring of aircraft performance, and the

economic incentive to the airlines and manufacturers, aircraft component reliability problems are

solved quickly,

“DC-10 accident, Chicago, IL, May 25, 1979.
104

Engine Shutdown and Failure Rates

Modern jetliners are capable of operating safely,

even in the unusual event of an engine failure in

any phase of flight; indeed, engines are sometimes

shutdown in flight as a precautionary measure if a

problem is detected or suspected. All in-flight engine shutdowns must be reported to FAA; the airframe and engine manufacturers also keep close tabs

on these data.

The engine shutdown rate declined for U.S. jet

fleets during the past decade, with the current engine shutdown rate for the familiar B-727s, B-7375,

and DC-95, falling to about half the rate of the mid1970s. 38 (See figure 5-6.) A more critical subset of

these events, engine noncontainments39 for a specific aircraft type, occur fewer than 10 times per year

worldwide. These are broad statistics; specific en-

‘HFederal Aviation Administration Air Carrier Aircraft Utilization

and Propulsion Reliability Reports and Boeing Commercial Airplane

Co. data.

‘9A noncontainment occurs when an engine component fails and

penetrates the outer casing of the engine.

Figure 5-6.–Basic In-flight Shutdown (IFSD) Rate,

(domestic operators only) B727/JT8D Engines

I I I I I I I 1 1 1 1 I I I r

1970 1975 1960 1965

Year

SOURCE: Office of Technology Assessment based on Boeing Commercial Airplane Co. data.

gine model series, as well as individual air carrier

maintenance practices, should be considered in engine reliability analyses. However, these data show

that overall, engine reliability is not a problem.

Safety Reliability of Other Components

The airframe manufacturers collect data on the

failure rates of other aircraft parts, such as hydraulic, pressurization, and electrical systems. OTA obtained data for worldwide fleets only,40 but they

showed that these events also occur infrequently.

In-flight pressurization loss and single system electrical power loss happen about 5 times each in a

million flight-hours. The trends over time for these

events are shallow, and depending on the aircraft

type, increase or decrease. Single system hydraulic

power loss occurs more frequently (about 60 events

per million flight-hours in 1986), but the rates have

consistently declined for all the Boeing models.

Airlines are required41 to report certain aircraft

failures, defects, or malfunctions to FAA. This information, along with reports from independent

maintenance and repair facilities, are entered into

FAA’s Service Difficulty Reporting System (SDRS).

The large volume of SDRS data-enables FAA to

identify aircraft mechanical problems that could

otherwise go unnoticed. However, FAA does not

enforce the reporting requirements or verify the accuracy of the data. While SDRS data trends are useful as problem alerts, they do not constitute sound

measurements of aircraft component reliability

changes.

Unscheduled Landings

Due to the cost involved42 and the inconvenience to the passengers, an airline will divert a

flight to an airport other than the final destination

only if a serious event occurs. While some unscheduled landings, resulting from weather-related airport closures or passenger medical emergencies, are

beyond the control of the airline, maintenance or

operating practices may cause mechanical-related

flight diversions. If the criteria for deciding on

whether to divert remain consistent, trends in

‘Boeing data.

4114 CFR 121.T03 and 121,705 Uan. 1> 1987).

qZFor example, the average direct operating expense for Boeing 727

-

200s in air carrier service is over $2,100 per hour.
105

mechanical-related unscheduled landings will give

one indication of changes in the reliability of critical aircraft components. FAA requires that airlines

report all unscheduled landings due to mechanical

difficulties or malfunctions. However, since these

reports are part of SDRS, the problems with database validity discussed above apply.

OTA examined unscheduled landing data from

the SDRS database. A comparison of the unscheduled landing rates (reported events per departure)

for the major carriers revealed differences as great

as a factor of 12 among them.43 OTA obtained

some data, which are assumed to be accurate, directly from a few airlines. The FAA data on unscheduled landings ranged from more than 80 percent below the airline records in one case to 12

percent above in another. OTA concludes that this

subset of SDRS data, as currently kept, cannot be

used for trend analysis or comparisons among

airlines.

Boeing also keeps unscheduled landing data, but

the data for U.S. operators was limited. The unscheduled landing rate for the B-747 (the only type

with available data) steadily declined since its introduction, falling by half since the mid-1970s.

Personnel Capabilities

Theoretically, human performance reliability

could be measured in a similar manner, but data

collection on these capabilities is difficult, especially

in the operating environment. Human capabilities

such as motor skills, alertness, and cognitive skills

(for example, decisionmaking and judgment) are beq~h~se differences usually go unnoticed, since Federal Aviation

Administration inspectors review data from their respective carriers

only.

lieved to play major roles in human error-caused

aircraft accidents. Selection, training, experience,

and working conditions, as well as physiological, psychological, and sociological status, affect the capabilities of the aviation system work force. However,

the magnitude and direction of the interrelationships between and among these factors is poorly understood. Current data on the underlying human

failure causes that culminate in accident-causing errors are studied by only a few experts. Consequently,

identifying, developing, and implementing countermeasures is hampered by limited understanding of

effective ways to modify human behavior and

attitudes.

Since human error is involved in the majority of

commercial aviation accidents, better collection and

analysis of data on human capabilities and failures

is the cornerstone of future gains in aviation safety.

Additionally, research and data collection to identify innovative and effective human error countermeasures is essential.

Traffic Environment

About 20 percent of the Part 121 fatal accidents,

and less than 5 percent of total accidents, result from

traffic environment factors.44 Traffic environment

factors include the reliability of the ATC system and

airport and airway facilities, along with air traffic

levels and mixes. Any one, or several of these variables may be involved in any given accident. However, the traffic environment accidents that fall into

specific categories, such as midair collisions or those

caused by ATC errors, are so rare that trends cannot be determined.

WOTA analysis of Nationa] Transportation Safety Board accident

briefs.

MANAGEMENT PRACTICES

Managerial practices, from corporate policy-setting widely. This section describes changes in industryto pilot decisionmaking, affect airline safety. The wide practices since deregulation, and highlights sigselection and training of employees and the main- nificant differences among carriers.

tenance and operation of vehicles and equipment

are major components of the performance capabil- Currently, FAA evaluates management practices

ities of the aviation system. While FAA sets stand- through inspections, such as the on-site audits.

ards and conditions for these practices, individual Ideally, the FAA inspector becomes familiar with

airline procedures to meet these guidelines vary the details of an airline’s operations and is
106

knowledgeable about practices at other carriers.

FAA uses inspections primarily for coaching and

disciplining airlines, rather than analysis, and has

kept few historical records of inspections.45 Consequently, FAA has no systemwide qualitative data

on airline management practices or changes in them.

Moreover, many of the results or effects of management practices are not investigated or are unmeasurable, and the complex interactions of management

processes leave few clear cause-and-effect trails.

Seeking supplementary sources for information

about changes in management practices over the

‘;U.S. Congress, General Accounting Office, Aviarion Saf&y:

Needed lmprmements in FAA $ Airline lnspmtion Program Are Underway, GAO/RCED 87-62 (Washington, DC: May 1987), pp. 24-38.

past decade, OTA examined economic data reported by the airlines, such as flight schedules and

maintenance expenses. Additionally, OTA solicited

answers to a confidential survey from airline pilots,

mechanics, and company officers, and through a

contractor, conducted case studies suppl

on-site interviews with four airlines.

Maintenance

As controlling operating costs became

:mented by

ncreasingly

important, attention focused on whether economic

pressures would force carriers to cut corners on

maintenance. OTA found that maintenance expenditure data for the major carriers show no evidence that airlines unduly cut costs. Moreover, the
107

accident record for the large airlines and data on

aircraft mechanical reliability reflect no increase in

aircraft system failures, as might be expected if maintenance quality had deteriorated.

Declines in maintenance expense as a percentage

of total operating expense are not good measures

of changes in the quality of airline maintenance.

Technological advances and efficiencies from modern maintenance inspection devices and inventory

management systems affect maintenance expense,

while fuel costs and nonmaintenance labor are large

and widely fluctuating contributors to operating

costs. Maintenance expense trends for specific aircraft types and models are more meaningful. Additionally, since maintenance requirements depend on

the amount of aircraft use, expense data should be

normalized by flight hours or departures.

Industry-wide on average, flight equipment maintenance expenses (in constant dollars) for specific

aircraft models have increased since the early 1980s

(see figure 5-7). Due to differences in accounting

methods, route structure, and fleet size and age,

maintenance expenditure comparisons among individual airlines must be viewed cautiously. OTA examined data for the eight major air carriers that

operated the Boeing 727-200 during the past decade (1976 to 1986), since the B727-200 was the most

common aircraft model over that period. For each

airline, the trends in maintenance costs per flighthour and per departure have increased since 1982

and reached the highest levels of the decade in either 1985 or 1986.46

OTA identified three broad maintenance-related

changes within the airline industry that warrant future attention. The quality of maintenance is affected by more contract maintenance, more aircraft

leasing instead of owning, and more flight operations and tighter schedules.

Major carriers have consistently contracted with

outside companies for about 11 percent (based on

dollars spent) of their maintenance needs, while the

smaller national carriers contract for about 40 per--

cent. The rapid growth of the national carrier segment of the industry (over 250 percent in flighthours in 10 years v. 21 percent for the majors) caused

+fiOne airline had its highest expense levels with respect to departures only and not to flight-hours.

Figure 5-7.—Average Flight Equipment Maintenance

Expense for B727-200 Fleeta

700 “ -

650-

/

/

197677 78 79 80 81 82 83 84 65 86

Year

~ Dollars/revenue aircraft departure

+ Dollars/revenue aircraft hour

aMajor carriers only.

SOURCE: Office of Technology Assessment based on Research and Special Programs Administration data.

the total contract maintenance use for the industry to increase from 12.5 percent in 1983 to 16 percent in 1986. While contract maintenance should

not be any less safe than in-house maintenance, it

places an important aspect of a carrier’s safety network in another company’s hands. Airlines, by regulation, must provide their own inspectors to monitor contractors’ work, as the responsibility for

airworthiness rests with the operator-of the aircraft.

Contract maintenance, by its nature, is not as easy

as in-house work to monitor and manage.

The number and value of aircraft in scheduled

and charter services that are not owned by the carriers operating them has grown significantly. OTA

estimates that over half of all aircraft transactions

for new and used planes in the United States since

1984 involved leases. In 1986, leasing companies

bought 10 percent of the total output of Boeing and

Douglas; orders were expected to grow to 14 percent in 1987. Since the aircraft’s long-term value is

not theirs to preserve, some operating carriers

changed some aspects of their maintenance programs. For aircraft nearing the end of their leases:
108

. periodic inspections are used in lieu of perma~

nent fixes for complying with airworthiness

directives when possible;

. engines, airframes, landing gear, and other lifelimited components (replaced after a fixed number of hours or landings) are near the ends of

their estimated lives; and

. corrosion is treated only to the degree required. 47

Cost reductions such as these affect economic maintenance primarily, as opposed to airworthiness maintenance. For example, an aircraft that has been

flown up to a major overhaul requirement can be

worth as much as 65 percent less than one that is

progressively and currently maintained.48 While

leased aircraft meet airworthiness standards, the

question remains open as to whether operatorowned aircraft that may receive more extensive

maintenance are safer. No industry-wide data are

currently available that compare the safety impact

of operator-owned aircraft maintenance to leased

aircraft maintenance.

Precise flight schedules are required for efficient

operation of hub and spoke systems. OTA research

corroborated press reports that pilots and mechanics feel pressure, implicit and, in some cases explicit,

to overlook mechanical problems to prevent delays.

In addition, special FAA maintenance surveillance

conducted in 1987 found that a few airlines improperly deferred maintenance regarding minimum

equipment lists, a problem FAA addressed in spring

1988 by tightening required procedures. Finally,

OTA research indicates that several airlines do occasionally postpone maintenance, and many choose

lower levels of maintenance when cash flow is a

problem or when using leased aircraft.

Operations

The major operating changes in commercial aviation over the past decade were the expansion of hub

and spoke systems and the record growth in flights

by the major, national, regional, and commuter airlines. The primary impacts are that airports have

reached their traffic capacity limits, and airline

‘7Slmar, Hellieson, and Eichner, “Safety of the Air Transportation

system in a Deregulated Environment,” OTA contractor report, OCtober 1987.

‘UIbid.

schedules have increased demands on the air traffic system equipment, facilities, and personnel, creating traffic congestion and delays (see chapter 7).

Additionally, operating practices affect the number

of flight-hours and departures experienced by each

airline’s pilots and aircraft.

Since the early 1980s, the airlines, on average,

have increased the number of flight-hours and

departures per aircraft per day, although current utilization rates are generally below 1979 levels for aircraft types in existence before deregulation. Since

maintenance requirements are primarily flight-hour

or cycle dependent, increased utilization necessitates

more frequent maintenance on a calendar basis. Additionally, the major airlines have increased the

productivity of their mechanic work forces. Seven

of the 10 major carriers in existence at the end of

1986 operated more flight-hours per mechanic recently (1983-86) than they did prior to deregulation.

Of greater concern is the effect of increased hours

and departures per day on pilot performance. While

FARs set limits on flight-hours over various time

periods, they do not address duty-hours or departures, both of which affect pilot fatigue and are covered in the aviation regulations of other countries.

(See chapter 6.) Few airlines keep track of pilot duty
109

time; the pilots from five out of eight large airlines

responding to OTA’s survey indicated that duty

time has increased or become more inconvenient

since deregulation. On the other hand, pilot flighthours have not changed much, since they have remained close to the upper limits established either

by labor contracts or Federal regulations. Other

environmental factors, such as operational complexity and traffic density, also affect pilot fatigue. However, recent considerable gains in the understanding of fatigue have not been transferred to the

operating setting.49

Hub and spoke systems require finely tuned flight

schedules—a single flight cancellation or delay can

disrupt the flight connections for passengers in many

cities. Self- or management-induced pressures to

meet schedules may adversely affect pilot performance and decisionmaking. One pilot stated that he

believed intimidation was the intent when his airline made computer checks of pilots’ maintenance

entries in the aircraft logbooks; those who were perceived by management as making too many entries

were called into the chief pilot’s office and required

to justify their actions. The effects of such stress factors are difficult to quantify. See chapter 6 for further discussion of the effects of stress.

Regional/Commuter Airline Operations

According to RAA, consolidation of the commuter and regional airlines is expected to continue

into the early 1990s, with two-thirds of currently

operating airlines merging or failing and many becoming wholly or partly owned by the large airlines.50 This development can be beneficial for

safety if the parent company imposes strict operating and maintenance requirements on closely linked

affiliates. For example, Allegheny Airlines (now

USAir) formed the Allegheny Commuter System

in 1967 and required that member airlines adhere

to standards more stringent than FAA’s in return

for marketing, scheduling, and financial services.

From 1970 to 1980, the Allegheny Commuters had

a better safety record than the jet carriers.51

4qR Curtis Graeber, National Aeronautics and Space Administration, “Ames Research Center, personal communication, Mar. 2, 1988.

‘Aviation Week & Space Technology, “Economics, Code Sharing

Threaten Survival of Commuter Airlines,” Apr. 27, 1987, p. 57.

5] Clinton V. Oster, Jr. and C. Kurt Zorn, “Commuter Airline

Safety,” Deregulation and the New Airline Entreprenuers, John R.

Meyer and Clinton V. Oster, Jr. (eds.) (Cambridge, MA: The MIT

Press, 1984), ch. 5.

Some major carriers have placed regional pilots

on their seniority lists and guaranteed future employment opportunities. Pan Am established such

an arrangement after purchasing Ransome Airlines

(now Pan Am Express); the pilot turnover rate went

from 12 percent per year to approximately zero.52

Continental Airlines, which owns Britt Airways,

PBA, Rocky Mountain Airways, and a major interest in Bar Harbor Airways, established a commuter division to coordinate aircraft purchases and

pilot training. Continental plans to replace the 20

types of aircraft used by its affiliates with just 3 types

and to the standardize the training of mechanics

and pilots. Additionally, Continental is using its regional airlines to train pilots for the parent company. For example, some new hires fly as flight engineers on Continental for 1 year, then become

co-pilots on a Continental Express aircraft, and finally move up as co-pilots at Continental (although

some will fly as captains at the regional first).53

One conclusion of FAA’s National Air Transportation Inspection program was that “. . . a significant change in operations of an existing carrier, such

as a change in range of operation or in size of aircraft flown . . . can provide a warning signal for potential problems.”54 Yet the principal inspector assigned to a Part 135 commuter often is responsible

for a number of other airlines. For example, the principal operations inspector for one commuter airline

testified before NTSB that he did not have time to

carry out his oversight tasks effectively because he

was responsible for 20 other certificate holders.55

While the expected consolidation of regional/commuter airlines may ease some of FAA’s workload

in the future, the ensuing turmoil as the reorganization takes place warrants close FAA attention.

Moreover, the upturn in the commuter accident rate

for 1987 is noteworthy; in only one other year since

1978 did the rate increase from the previous year.

JzTim Cwik, director of operations, Pan Am Express, personal communication, Mar. 10, 1988. sjAviation wf&k & Space TwhnoloW, “Regional Airlines play Key

Role in Continental’s Pilot Development,” Nov. 16, 1987, pp. 40-41.

54U.S. Department of Transportation, Federal Aviation Administration, “National Air Transportation Inspection Program,” report for

the Secretary, Mar. 4- June 5, 1984, p. 36.

55Jim Burnett, chairman, National Transportation Safety Board,

“Safety Recommendation to Federal Aviation Administration,” letter, Oct. 9, 1986, p. 7.
170

Employee Selection and Training

Aviation professionals—pilots, controllers, mechanics, and others—are the key components of the

air safety system. Their skills and flexibility prevent

countless mishaps each day, while their mistakes are

dominant factors in aircraft accidents and incidents.

Employee selection and training are important methods used by the airlines and the Federal Government for controlling human errors, though they are

not panaceas (see chapter 6). Airline flight crew selection and training have changed markedly in the past

decade.

Selection

Although flight crew hiring declined between 1979

and 1982, strong traffic growth brought record demand for pilots, and more pilots have been hired

since 1983 than in the period from 1967 to 1983.

Data collected by the Future Aviation Professionals

of America indicate that, on average, a greater percentage of new hires have no military experience,

have less than 2,000 hours total flight-time, have

no jet or turboprop experience, and have no airline transport pilot or flight engineer certificate. Airlines are also relaxing requirements for age, education, eyesight, and physical size.

Examined by airline type, these changes are more

pronounced (see table 5-7). The most notable

change 56 for the major carriers is that new hires

with less than 2,000 total flight-hours have increased

from less than 2 percent to more than 13 percent.

For the nationals, the number of new cockpit crew

members with military experience57 has dropped

‘All changes are for the period 1983 to 1986.

‘;The airlines regard military backgrounds highly. The military services have rigorous pilot selection and training requirements; only the

most skilled and motivated pilots earn their wings.

However, from the aspect of cockpit management and decisionmaking, the “can do” attitude instilled in the military flyer is not appropriate if applied to commercial passenger operations.

from 82 to 34 percent. At other jet carriers and regional airlines, 29 percent of the new hires have no

jet or turboprop experience, compared to less than

3 percent at the larger airlines. Finally, the number

of new pilots at the regional carriers with less than

2,000 hours of total flight-time increased from less

than 9 percent to 29 percent.

Flight-time or military background, although used

for years by the airlines, are only rough estimates

of actual pilot skills. Developments in aircraft and

training technologies may correct some deficiencies

in pilot experience. Accident statistics for the large

airlines show no correlation with pilot experience;

no aircraft involved in an accident since 1976 was

flown by a captain with 2,500 hours or less of flighttime. Actual experience in a specific aircraft type

and airline might be more predictive of accident risk.

However, OTA is aware of no studies in this area,

though NTSB and FAA have warned against pairing inexperienced captains with inexperienced copilots.

The rapid growth of the large carriers has meant

increased competition for limited resources, a battle the regional/commuter can rarely win. The demand for more commercial airline pilots places additional pressure on the regional/commuters: they

must compete for new hires and at the same time

see a large number of their trained pilots leave for

the high paying majors. Some small airlines have

experienced pilot turnover rates exceeding 100 percent per year.

Training

A comprehensive analysis and qualitative comparative assessment of employee training programs

across the airline industry is beyond the scope of

this study. The best source for such information

would be FAA inspections and audits; however,

these data are presently unavailable or inaccessible.

Table 5-7.—Qualifications of New-Hire Commercial Flight Crews (percent, by year)

Major airlines National airlines Other jet airlines Regional airlines

Pilots with 1983 1986 1983 1986 1983 1986 1983 1986

Less than 2,000 hours total

flight time . . . . . . . . . . . . . . . . . . . . . . . 1 13 0 11 14 12 9 29

No military experience. . . . . . . . . . . . . . . 46 56 18 66 55 70 83 88

No jet or turboprop flight time. . . . . . . . 1 2 1 6 24 29 32 28

No air transport pilot certificate and

no flight engineer certificate. . . . . . . . 18 26 24 41 42 56 77 76

SOURCE: Office of Technology Assessment based on Future Avlatlon Professionals of America data, as of May 1987.
111

OTA relied upon case studies of selected carriers

and the responses to survey questionnaires for insight on quality differences over time and among

the airlines.

After a series of highly publicized incidents and

increased attention by labor unions to airline training programs, FAA announced an initiative to examine FARs dealing with pilot training. Whether

or not the quality of training at some airlines has

declined recently, over the past 15 years training

has substantially improved. Sophisticated, fullmotion simulators used by all the major carriers, or

other advanced training devices, allow training

scenarios (e. g., flight into severe weather, engine

fires, or other extreme emergencies) that could never

be permitted in actual training aircraft. Cockpit crew

management is a significant factor in a number of

air carrier accidents, and crew coordination training, used in conjunction with simulations of operational flights with full crews, adds an important

dimension to the background of the modern airline

pilot.

At least three U.S. carriers are establishing programs at universities to take pilot candidates with

no aviation experience and prepare them for airline careers. General aviation training has dwindled

in recent years—the number of private pilot certificates that were issued in 1986 represented a 35 percent drop from the 52,000 issued in 1982. This reduction has come at a time when the airlines are

drawing fewer of their pilots from the military. Moreover, early training and experience has a strong influence on a pilot’s future performance—even after

he has received advanced training.58

While most airlines claim to have cockpit resource

management or line oriented flight training programs, OTA’s research indicates that relatively few

pilots experience them. United Airlines and Pan Am

are the only carriers with formal, annual crew coordination training programs using full mission

simulation for all flight crew members. Most of the

pilots surveyed felt that present recurrent training

programs are insufficient; however, all confirmed

that the training is consistent with current regulations.

Mechanics from three airlines indicated to OTA

that they believed that present Federal standards

for maintenance training are too low–for example,

recurrent training is not required for aircraft mechanics or inspectors. At one carrier, the number

of maintenance instructors was cut by 75 percent.

‘Frank Monastero, T.M. Monitor Corp., personal communication,

Mar. 7, 1988.

MANAGEMENT POLICIES

“Safety begins at the top” is an accepted maxim

throughout aviation. Senior corporate officials set

the safety framework within their organizations by

the policies they establish. Although airline and government officials alike profess a willingness to pay

any price for safety, in reality, this is impractical.

While safety is an important passenger concern, convenience and cost are the primary variables that determine demand for air transportation. 59

Cost control is critical to the success of any organization, and safety, like fuel, maintenance, or advertising, has a cost. However, safety costs are rarely

5%obert W. Simpxm, Fhght Transportation Laboratory, Massachusetts Institute of Technology, “A Theory for Domestic Airline Economics, ” unpublished manuscript, January 1977.

defined clearly, since management of each element

in a system plays a role in safety.

In recent years, a number of airlines have eliminated or cut back engineering, weather, medical, and

safety departments, thereby shifting some safety

responsibilities within the company and moving

other tasks outside the company. While changing

aspects of a redundant safety system may reduce

safety, a number of questions need to be answered

before such actions cause undue alarm. If marginal

improvements in other safety areas balanced the

loss, two layers of redundancy in 1988 could be more

effective than three layers in 1978, for example.

Since corporate actions are many steps removed

from accident rates, identifying a clear cause-andeffect relationship may be impossible, although one
112

measure of corporate safety policy might be relative

compliance with safety regulations. Adherence to

Federal regulations gives an indication of corporate

attitude or competence, both critical with regard to

safety. While FAA has records of the enforcement

actions taken against carriers that violated regulations, no records have been kept on the amount

of inspection activity each carrier experienced over

time, preventing calculation of a valid violation

rate.60

@For further information on the potential uses of Federal Aviation

Administration inspection data records for measuring airline safety,

see U.S. Congress, General Accounting Office, Aviarion Safery: Measuring How Safely Individual Airlines Operate, GAO-RCED-88-61

(Washington, DC: March 1988).

CONCLUSIONS AND POLICY OPTIONS

On the basis of its review of accident data, OTA

concludes that commercial aviation safety in the

1980s continues to be excellent. However, human

errors are the predominant causes of over 65 percent of all accidents that do occur, and this distribution has not changed in recent years. Moreover,

weather-related accidents from unexpected severe

conditions often involve faulty decisionmaking or

communications. Aircraft component failures, factors in over 40 percent of total accidents, are often

compounded by human error.

OTA examined numerous nonaccident safety

databases for indications of changes in safety risk.

While inadequacies in data collection and management or the nature of the safety events limit the validity of such data, nonaccident databases in three

categories—ATC environment, aircraft reliability,

and human performance—can contribute to aviation safety policy decisionmaking. For example,

while data on aircraft component failures indicate

improving aircraft system reliability, airline flight

operations, especially scheduling and timing, have

caused record levels of air traffic and controller workload in recent years. Increases in commercial aviation traffic correspond closely to the rise in reported

NMACs, suggesting that future traffic growth is a

cause for concern.

The four major causal factors in commercial

aviation accidents are human performance,

weather, aircraft component failure, and the air

traffic environment. OTA concludes that the

greatest potential for additional safety problems

lies in the areas of air traffic, as continued vigorous traffic growth and increased traffic densities

for longer periods of time at more airports could

outstrip the capabilities of the traffic system. However, continuing gains in aircraft mechanical reliability and in understanding and coping with severe

weather could well outweigh the effect of even a sizable decline in air traffic safety. The rate of pilot

error-caused accidents has remained constant for the

past decade and few data on pilot performance have

been collected and analyzed from the operating environment, making reliable predictions of future

trends difficult.

OTA concludes that if Congress wishes to improve commercial aviation safety significantly, enhancing human performance is a top priority. Civilian aviation in the United States lacks a long-term

human performance research and development program. While innovative research is best done outside of a regulatory agency, FAA could serve as the

focal point and catalyst for cooperative efforts at

understanding human performance and the factors

influencing it and communicating the findings to

the aviation system operators and managers. In the

short term, the resources and understanding within

FAA, NASA, the Department of Defense, universities, industry, and special interest groups could be

combined in advisory working groups. These could

provide guidance for developing and disseminating

training procedures for upgrading crew coordination and decisionmaking.

An important research area is the optimal design

and procedures for use of automation in the cockpit and in ATC facilities. Analyses of human errors and their causes need to be implemented in the

airworthiness and operating standards for aviation

systems and organizations.

Increasing the capability to predict and detect

severe weather such as windshear and communicate this information to the cockpit is another pri-
113

ority. Data also indicate that air traffic safety will

be further improved with the introduction of collision avoidance equipment and the expansion of

Mode C transponder requirements. Safety could be

upgraded through the addition of conflict alert capabilities at large radar terminals and the development of ground collision alert and runway intrusion detection systems for airports.

Airline management operating practices, along

with the ATC system, are the control valves for

commercial aviation safety. Maintenance expense

data show increased spending (in constant dollars)

across the industry during the past 5 years. Some

airlines have lowered hiring standards, increased

duty time, and increased employee stress through

reorganizations and wage cuts. However, the effects

of these and other management practices on human

performance, and subsequently on system safety, are

difficult to quantify. FAA’s inside view of airline

management procedures through periodic and unannounced audits and inspections is critical for

assessing the relative safety value of airline management procedures and any changes over time.

OTA concludes that Federal oversight, through

standards, inspections, and enforcement is key to

upholding air carrier maintenance reliability and

operating safety. Three FAA responsibilities need

continued support: the training program for in-0

specters, work force levels sufficient to match

changes in industry operating patterns, and automated systems for tracking and analyzing FAA.

collected data and airline computerized records.

Based on the operating and marketing changes

underway, the Part 135 commuter industry warrants

the most critical FAA oversight during the shakeout

expected over the next few years. While it is too early

to draw conclusions regarding patterns or causes for

1987 commuter accidents, last year’s upturn in accidents is noteworthy; in only one other year since

1978 did the accident rate increase from the previous year.

improved safety data collection and analysis by

FAA would permit better Federal understanding o f

developin g aviation safety problems. While FAA

analyzes air traffic safety data and is upgrading its

collection and management of inspection data, the

agency could benefit greatly from analysis of air

carrier-related safety data, such as operating practices and all types of incidents. FAA principal inspectors have a good understanding of their respective air carriers’ safety postures; but they are often

unaware of the activities at other airlines. Additionally, FAA requires only that airlines meet minimum

Federal standards; FAA might consider encouraging airlines to strive to improve their safety posture

above the base level. A program to consolidate and

communicate the safty ‘knowledge

principal inspector and airline would

enhance safety.

from each

do much to
Chapter 6

The Human Factor in

Commercial Aviation

Photo credit: United Airlines

People are central to aviation safety,

.

.
CONTENTS

Page

Human Error... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..........................118

Preventing Errors. . . . . . . . . . . . . . . . . . + . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . + .......119

Compensating for Errors . . . . . . . . . . . . . . . . . . . . . . + . . . . . . . . . . .................120

Human Factors Data. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . t . . . . . . . . . . . . . . . . ..120

Industry and Federal Roles in Human Factors . ................................121

Growing Concerns . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ....................121

Federal Responsibilities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .................127

Industry Responsibilities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .................129

Labor’s Role.... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ......................131

Conclusions and Policy Options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..........131

Box —

Box

6-A. Air

Figure

6-1. Part

Table

Traffic Control Automation . . . . . . . . . . . . . . . . .

Figure

121 Total and Human Error-Caused Accidents

Table

Page

. . . . . . . . . . . . . . . . . . . . . . . . 125

Page

. . . . . . . . . . . . . . . . . . . . . . . . 117

6-1. Significant Jetliner Accident Causes in 93 Major Accidents Worldwide

(1977-1984) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 117
Chapter 6

The Human Factor in Commercial Aviation

The people who operate and support the U.S.

aviation system are crucial to its safety; the resourcefulness and skills of crewmembers, air traffic controllers, and mechanics help prevent countless mishaps each day. However, despite the fact that the

total accident rate for large jets declined over the

past decade, the National Transportation Safety

Board data show that the rate of accidents involving pilot error did not change (see figure 6-l). Policy, procedures, or technology designed to reduce

human error would substantially influence safety,

as human error is a factor in over 65 percent of commercial aviation accidents.

An analysis of major accidents involving large,

commercial transports, identified flight crew errors

as the leading significant causal factors in these accidents,

l For accidents having multiple causes

‘Richard L. Sears, “A New Look At Accident Contributors and the

Implications of Operational and Training Procedures,” Influence of

Figure 6-1.— — Part 121 Total and Human

Error-Caused Accidents

6

5

4

3

2

1

0

75-77 78-8 0 81-8 3 84-8 5

Years

_ Al accidents ~ All human errors ~ Pilot errors

SOURCE: Office of Technology Assessment based on National Transportation

Safety Board data, 1975-85. Data from 1986 and 1987 are not yet

available.

(over 70 percent in this analysis), reducing the likelihood of one causal factor reduces substantially the

overall probability of the accident occurring. As

shown in table 6-1, flight crew causes predominate,

although other human errors are elements of many

Training, Operational and Maintenance Practices on Flight Safety,

Proceedings of the Flight Safety Foundation’s 38th Annual International Air Safety Seminar, Nov. 4-7, 1985 (Arlington, VA: Flight Safety

Institute, 1985).

Table 6-1 .—Significant Jetliner Accident Causes

in 93 Major Accidentsa Worldwide, 1977.84

Percent of

Causal factor accidents

Flight crew causes:

Pilot deviated from basic operational

procedures. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Inadequate crosscheck by 2nd crew member. . .

Captain did not respond to crew inputs . . . . . . .

Crews not conditioned for proper response

during abnormal conditions . . . . . . . . . . . . . . . .

Pilot did not recognize the need for

go-around . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Deficiencies in accepted navigation

procedures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Pilot incapacitation . . . . . . . . . . . . . . . . . . . . . . . . .

inadequate piloting skills . . . . . . . . . . . . . . . . . . . .

Pilot used improper procedure during

go-around . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Crew errors during training flights . . . . . . . . . . . .

Pilot not trained to respond promptly to ground

proximity warning system command . . . . . . . .

Pilot unable to execute safe landing or goaround when runway sighting is lost . . . . . . . .

Operational procedures did not require use of

available approach aids . . . . . . . . . . . . . . . . . . . .

Captain inexperienced in aircraft type . . . . . . . . .

All other causes:b

Design faults. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Maintenance and inspection deficiencies . . . . . .

Complete absence of approach guidance . . . . . .

Air traffic control failures or errors. . . . . . . . . . . .

Other . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Weather information insufficient or in error . . . .

Runway hazards . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Air traffic control/crew communication

deficiencies , . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Weight or center-of-gravity in error. . . . . . . . . . . .

33

26

10

9

6

4

4

4

3

3

3

3

3

3

13

12

10

9

9

8

7

6

5

aA major accident involves either a fatality Or a hull loss.

blncludes other human errors, equipme-nt failures or problems, weather,

maintenance, and airport facilities.

SOURCE: Office of Technology Assessment based on Richard L. Sears, Boeing

Commercial Airplane Co., “’A New Look at Accident Contributors and

the Implications of Operational and Training Procedures, ” Influence

of Training, Operational and Maintenance Practices on flight Safety,

Proceedings of the Flight Safety Foundation’s 38th Annual international Air Safety Seminar (Arlington, VA: Flight Safety Foundation, Nov

4-7, 1965), pp. 29-51.

117
118

of the remaining causes. OTA analyses of accident

data (see chapter 5) found that human errors initiate over half of U.S. jetliner accidents. Additionally, OTA found that most of the fatal accidents

caused by aircraft component failure also involve

human error.

Post-accident investigations usually uncover the

details of what happened. In the case of mechanical failures, accident data analysis often leads logically to why the accident occurred. It is much more

difficult to determine the precise reason for human

errors. Without an understanding of human behavior factors in the operation of a system, preventive or corrective actions are impossible.

Human factors understanding is especially important to systems in which humans interact regularly

with sophisticated machinery and in industries

where human error-induced accidents can have catastrophic consequences. However, human factors

is not treated as a “core” or “enabling” technology

in commercial aviation. Technical decisions for aircraft design, regulation, production, and operation

are based on “hard” sciences such as aerodynamics,

propulsion, and structures. Human capabilities do

not lend themselves readily to consistent, precise

measurements, and human factors research requires

much more time and cooperation than most other

aeronautics research.2 Data on human performance and reliability are regarded by many technical experts as “soft,” and receive scant attention in

some aviation system designs, testing, and certification. When data are used in designs, it is often

after the fact. This chapter explores areas of aviation safety where human factors are especially important and evaluates Federal programs to address

human factors in accident prevention.

‘R. Curtis Graeber, National Aeronautics and Space Administration Ames Research Center, in U.S. Congress, Office of Technology

Assessment, “Transcript of Proceedings–OTA Workshop on Human

Factors in Commercial Aviation Safety,” unpublished typescript, May

28, 1987.

HUMAN ERROR

The role of the human in an aviation system is

complex; thus the nature of human errors, from

mental to physical, in aviation accidents varies

widely. Mental or cognitive errors can include improper judgment or decisionmaking, while physical

errors may stem from motor skill deficiencies or

equipment design. A combination of physical and

mental processes may influence other kinds of errors, such as those involving communication, perception, or alertness.

Many types of human error are systematic, following certain predictable patterns; once these patterns are identified, countermeasures can be developed. For example, accidents due to pilots’ forgetting

to extend landing gear have been virtually eliminated in commercial operations by the introduction

of cockpit warning devices.

Much of the discussion in this chapter focuses on

fundamental human factors: how the interactions

of people, machines, and environment influence the

performance capabilities of physically fit, emotionally stable, human operators. However, management

practices, such as labor relations and work scheduling, also affect employee stress and fatigue. While

conditions that affect a person’s fitness and mental

health generally influence his performance limitations, little is known about the magnitude of this

relationship. Concerns about aviation management

practices are addressed later in this chapter.

For those types of human error that do not follow predictable patterns, intervention techniques

and limitation methods are difficult to develop. Furthermore, any change to a complex system like aviation safety can have wide-ranging and often unpredictable effects; thus, there are few simple solutions

to the problem of human error-caused mishaps.

Nonetheless, the options fall into two main categories: preventing or limiting the number of errors,

and compensating for errors that occur. This section will outline the methods used or available at

present and serves as the basis for later discussion

of many needed changes in Federal human factors

policies.

Preventing Errors

While preventing all human error is impossible,

error rates can be reduced. In aviation, as in other

fields, rules and procedures are used to limit errors
119

by modifying or restricting human behavior through

standards governing personnel qualifications, operating rules, and equipment design.

The first and basic step in minimizing error is employee selection—allowing into the system only those

operators least likely to make mistakes. Airline pilots and air traffic controllers must meet prescribed

health, age, and training requirements and pass written and operational tests of skills and knowledge.

For the select group that survives the culling, continued quality is maintained through training and

monitoring. Indeed, Federal regulations require the

periodic testing of flight crewmembers to check results of training and operational experience, including flight proficiency and system knowledge. Pilots

and controllers are also monitored through required

periodic medical examinations, possibly including

drug and alcohol testing in the near future. ]

Potential errors can be forestalled by restricting

human behavior. Careful control of the operating

environment is the most wide-ranging of the methods for addressing human error in aviation. Federal regulations in this area address airline procedures such as pilot flight-time, emergency operations,

and the use of checklists. Air traffic rules, including instrument approach and departure procedures,

separation standards, and weather minimums set

operational limits for users of the National Airspace

System.

Training, monitoring, and operating rules are not

enough, however, if the environment is poorly designed. “If human factors engineering is done properly at the conceptual and design phase, the cost

is high, but paid only once. If training must compensate for poor design, the price is paid every

day.”4 The Federal Government has the responsibility for setting appropriate standards for aircraft,

airports, and navigation aids. Ideally, equipment is

designed to reduce, not induce, human error.

To be optimally effective, these methods for controlling human behavior must be preceded by an

understanding of the root causes of human error.

However, this is an area still in need of much work.

JDrug and ~lcoho[ testing is used currently at some air traffic control facilities.

4Earl L. Wiener, “Cockpit Automation,” to be published in Human

Factors in Aviation, E.L. Weiner and D.C. Nagel (eds.) (San Diego,

CA: Academic Press, forthcoming), draft chapter, Mar. 23, 1987.

Most of the Federal Aviation Regulations (FARs)

aimed at limiting human error are based primarily

on past regulatory experience, not on scientific evidence. While previous experience is of course important, it is often insufficient or inappropriate in

a changing environment. Recent technological developments, such as cockpit automation devices and

displays, have outpaced the Federal Aviation

Administration (FAA) regulatory process.

Compensating for Errors

An alternate approach to addressing human error assumes that errors will occur and then mitigates or nullifies them. Central to this method is

an understanding of what errors occur; such information is provided by accident and incident investigations, which usually identify the human errors

involved. Successful ways of compensating for

known human errors entail changes to vehicles,

equipment, or the environment. Modifying human

behavior, even with respect to known types of human error, is a preventive measure as discussed in

the previous section.

Monitoring of some type is often involved in

negating errors. Warning devices are ubiquitous in

jetliner cockpits and have proven invaluable. For

example, the ground proximity warning system, required under FARs in 1975, has essentially ended

controlled flight into terrain accidents by U.S. carriers. However, alerting systems or other devices may

cause, as well as solve, problems. Excessive false

alarms unnecessarily distract operators and may lead

to the device being ignored or disabled. Consequently, a full system approach is required for all

human error solutions.

Outside monitoring of airline flights is accomplished through the Federal air traffic control (ATC)

system. Air traffic controllers detect gross navigation and guidance errors and provide useful information on weather and airport conditions to flight

crews. En route controllers, in turn, are automatically monitored—ATC computers record the separation between aircraft under positive control and

sound an alert if the distance falls below minimum

standards.

On the technological forefront of human error

control are “error-resistant” or “error-tolerant” systems based on automatic devices similar to those

86-680 - 88 - 5 : QL 3
120

Photo credit: Boeing Commercial Airplane Co.

Electronic cockpit displays indicate aircraft attitude,

speed, heading, altitude, navigation, and warnings,

such as windshear.

discussed earlier. The difference is that error-resistant

systems have the additional capability of controlling and correcting the pilot’s error. For example,

fly-by-wire technology on the Airbus A-320 prevents

the pilot from exceeding the operating envelope of

the aircraft—on-board computers will not allow the

aircraft to stall or overspeed, regardless of the deflection of the control stick. However, systems that seize

control are themselves potential sources of error.

Error-resistant systems should not take the place of

error prevention methods, but can serve as the last

line of defense against human errors.

Human Factors Data

Human error must be identified and understood

before appropriate solutions can be proposed. Data

are needed from both controlled laboratory experiments and actual flight operations.

One valuable source of field data is post-accident

analyses. However, such data may result in only

limited understanding of the cause of the human

error, especially if no flight crewmembers survive

or information is restricted because of litigation concerns. Another data source is reports from crewmembers concerning aviation incidents. The Aviation Safety Reporting System (ASRS), administered

by the National Aeronautics and Space Administration (NASA) at the Ames Research Center and

funded by FAA, collects such reports and FAA

guarantees anonymity and immunity from enforcement actions to reporters. s ASRS was designed to

gather analytical data, with emphasis on human behavior. To assure participants that the data would

be kept confidential, NASA was chosen to host the

system, since it is not a regulatory or enforcement

agency and had experience in human factors research. The program has proven valuable, supporting numerous studies by government, industry, and

academia.

ASRS has become so popular with the U.S. aviation community that the average number of reports

has increased from fewer than 800 per month in

1985 to over 1,700 per month in 1987. Until recently, the ASRS budget had not grown, forcing

NASA to divert resources to data processing at the

expense of data analysis and special studies. c For

fiscal year 1988, FAA increased ASRS funding from

$1.5 million to $1.9 million.

While industry and academia have conducted research in selected areas, the only consistent Federal

human factors research effort for civilian flight crews

has been maintained by the Aerospace Human Factors Research Division at NASA Ames Research

Center. During the past 10 years, research has emphasized automation, communications, cockpit resource management, use of simulators, visual perception, human sleep needs, and pilot fatigue. In

recent years, FAA has provided only limited support for NASA’s human factors research and development. However, a 5-year interagency agreement was initiated recently and NASA’s Office of

Aeronautics and Space Technology has obligated

fiscal year 1989 funds for human factors research

on aviation safety and automation at Ames and

Langley Research Centers.

FAA has supported selected cockpit research

projects both by NASA and private contractors,

5For more details on the anonymitv and immunity provisions of

Aviation Safety Reporting System, see ch. 4.

~William Reynard, chief, A\,latlon Safety, Reporting System, personal commumcation, Jan. 25, 1988.
121

and has conducted ATC human factors studies at

the Civil Aeromedical Institute (CAMI), the FAA

Technical Center, and with private contractors.

CAMI, under the guidance of the Associate Administrator for Human Resource Management and

the Office of Aviation Medicine, performs research

and evaluation on the influence of sleep patterns,

alcohol, noise, drugs, and age on performance; stress

management techniques; field performance measurement and evaluation (including operational errors); supervisor/manager selection and training;

and job/task analysis for better selection criteria.

Human performance data from actual operations

are difficult to obtain. Flight data recorders, cockpit voice recorders, or video cameras could be used

to collect such data. However, pilots and controllers

are sensitive to being monitored and are concerned

about the possible misuse of data, and few objective measurement criteria have been established.

While laboratory research provides insight into the

effects of automation, aeromedical stressors, and

crew interactions on operational safety, these findings must ultimately by verified in the field. NASA

Ames, in conjunction with the Air Line Pilots Association (ALPA), and some air carriers, has collected

some field data. Additionally, a number of university research projects, on topics such as cockpit resource management or automation in modern cockpits, are based on information gathered directly by

human factors specialists riding in jetliner cockpits.

INDUSTRY AND FEDERAL ROLES IN HUMAN

Growing Concerns

Human factors problems in commercial aviation

are not new: standards for personnel age, health,

training, and work shifts, along with aircraft design

and operation requirements and the ATC system

are all directed at preventing or minimizing human

errors. However, new technologies, Federal regulations and advisories, and industry and union initiatives have been more effective in preventing other

types of accidents, and the rate of pilot errorinvolved accidents has not declined in the past decade. Additionally, rapid changes in airline operating and hiring practices and developments in cockpit technology have outstripped the FAA regulatory

process. Most of the regulations dealing with human factors are not based on modern scientific findings, and few have been revised or reassessed in recent years. These problems are presented in detail

below.

Pilot Selection and Training

Rapid expansion of commercial airlines during the

past decade has created shortages in the supply of

qualified pilots. The situation has been exacerbated

by increased retention of military pilots who were

once the mainstay of the airlines (see chapter 5) and

declines in general aviation pilot training. For example, the number of new private pilot certificates

issued annually dropped from over 58,000 in 1978

to fewer than 35,000

ALPA statistics indicate

FACTORS

in 1986.7 Additionally,

that the number of airline

pilots reaching retirement age per year will increase

until at least 1999. The large commercial carriers

are increasingly recruiting pilots from the smaller

Part 121 regional and Part 135 commuter airlines,

resulting in rapid turnovers in the regionals’ pilot

work force, greater than 100 percent per year for

some. The training burden on these smaller carriers

is enormous. For example, in 1987, the flight crew

training costs at one regional airline exceeded the

pilots’ salaries.8 Moreover, large and small carriers

alike have been forced to lower their selection criteria for new hires (see chapter 5). FAA is just beginning to address FARs regarding training, experience, age, or health requirements.

Age and Health.—Given the changes in the operating environment, the shortages in the pilot supply, and advances in medical understanding and

technology, the age and health standards for air carrier pilots might need refocusing. The rule requiring mandatory retirement at age 60 for air carrier

pilots is one example, since from a medical perspective, age is a coarse predictor of human capabilities.

‘U.S. Department of Transportation, Federal Aviation Administration, FAA Sratjsrjcal Handbook of A\’iar~on (Washington, DC: pubhshed annually).

‘J. A. McIntyre, Air Line Pilots Association, personal communications, Mar. 3, 1988.
122

FAA statistics show clearly that general aviation pilots 60 to 69 years old have accidents at twice the

rate of pilots 50 to 59 years of age.9 However, data

are not available on what percentage of retired airline pilots continue to meet all the physical and

mental competency requirements for commercial

transport pilots. Questions that need examination

include: what types of medical testing would be necessary to allow these pilots to remain in the work

force? What criteria should be measured and what

is the appropriate frequency of examinations?

While drug and alcohol testing has been widely

discussed and might be required of transportation

workers by the Federal Government, other forms

of on-site monitoring such as testing pilot fatigue

over long flights have rarely been addressed. The

capabilit y exists or is being developed for real-time

monitoring of certain physical and mental parameters of operator health. The potential of these methods for improving operational safety is unknown,

although it could be substantial in the case of drowsiness, fatigue, or illness. However, the sensitive issue of privacy and other concerns must be considered and balanced against safety gains.

Experience.—FAR pilot qualifications have been

considered by many to be too low. For example, a

jetliner copilot can meet all requirements with only

250 total hours of flight-time.10 Until recently, this

has not been a concern since the airlines have traditionally set their own standards much higher than

the Federal requirements. However, while still well

above FAR minimums, the average qualifications

(total flight-time as well as other indicators of experience) of new pilots are decreasing (see chapter 5).

The rapid expansion of air carriers has also resulted in junior cockpit members advancing to captain without the “seasoning” that was common in

the past. While pilots formerly spent several years

as flight engineers and then several more as co-pilots

before moving into the left seat, promotion to captain with only months of experience is increasingly

common at some airlines.11 For example, at one

9Anthony I. Broderick, associate administrator for Aviation Standards, Federal Aviation Administration, personal communication, Mar.

31, 1988.

1014 CFR 121.437 (Jan. 1, 1987).

I I progression t. captain at part 121 air carriers currently takes several years on average. John O’Brien, director of Engineering and Air

Safety, Air Line Pilots Association, personal communication, Feb. 29,

1988.

mid-sized commuter, 45 out of 70 captains were in

their first year of employment.12 Additionally, the

replacement of three-person crew aircraft with twoperson crew transports means that newly hired crew

members increasingly receive their initial jetliner experience as co-pilots.13

Total time, whether hours in a logbook or years

in a crew position, does not give the complete picture of pilot experience, skill, or quality of training.

For example, full-motion flight simulators or advanced training devices enable a pilot to meet with

more emergencies and unusual situations in a 4-hour

training session than he may experience on the line

during a 20-year career. However, few measures of

pilot ability other than flight-time have been collected broadly and consistently. Alternative measures or tests of skill and experience could prove

useful.

Airline Training Programs.–FARs give wide

latitude to carriers with respect to training programs,

and flight simulators and computer systems add

dimensions to the training process. Modern cockpit technology has shifted the primary tasks of the

pilots from physically flying the aircraft to managing it. The adequacy of current training programs

and standards have been questioned; FAA has

stated that the entire pilot training and rating system needs reexamining and has initiated a program

to do so.14 Additionally, the importance of early

training and conditioning and their effect on future

pilot performance have not been fully considered

in commercial aviation,15 but are receiving increased attention by several airlines.

Some airlines have implemented training programs, called cockpit resource management (CRM)

training, which focus on flight crew management

and communication. Line oriented flight training

(LOFT), full mission crew coordination training conducted in flight simulators, is also considered valuable by a number of airlines and military aviation

groups worldwide. For example, United Airlines

‘~ McIntyre, op. cit., “ footnote 8. i IHoW~ver, the fli@t engineer position might nOt be effective as a

training base, as many flight engineers have had difficulty transitioning to a pilot position. Delmar M. Fadden, Boeing Commercial Airplane Co., personal communication, Mar. 1, 1988.

14DavidHughes,“Four.yearpilot Hiring Boom Creates Problems ‘or

Carriers,” Aviation Week & Space Technology, Oct. 5, 1987, p. 97.

15 Frank Monastero, aviation consultant, T.M. Monitor COrP.! Personal communication, Feb. 23, 1988.
123

Photo credit: The Singer Co Photo credit: National Aeronautics and Space Administration

Full-motion flight simulators re-create jetliner operations so realistically that pilots can be trained in them and certified

without flying the actual aircraft.

conducts an annual 3-da y training and proficienc y

checking program using CRM and LOFT. FAA has

supported this type of training by granting waivers

to United and Pan Am, allowing them to reduce

their cockpit crew recurrent training and proficiency

checks to one per year instead of the normal 6-

month check.16 There are yet no data proving that

CRM is effective, and no regulations mandating

CRM .

17 However, a Joint Government/Industry

Task Force on Flight Crew Performance, formed by

FAA in August 1987, has drafted an advisory circular on CRM/LOFT. Research is also underwa y

by the University of Texas at Austin to evaluate

the effects of CRM/LOFT on pilots at a number

of airlines and military squadrons.18

Type Ratings.–Unlike automobile or truck

drivers, airline pilots must be licensed for a specific

vehicle model. A pilot licensed to fly a B-737 is allowed to fly any version or derivative of the B-737,

provided he is trained on their differences, but can-

“Richard S. Jensen, Ohio State Unl\’ersity, “Feasibility Stud} for

the Asse<~ment of (hckpit Resource Management Traimng,” prepared

for U.S. Department of Transportation, February 1987, p. 10; and

O’Brien, op. cit., footnote 11.

‘;Ed Ccx)k, “The Regulator Horizon,” Cockpit Resource ,+!anagement Training: Proceedings of the NASA/MAC Workshop, NASA

(Jonferencc Publication 2455, Harr} W. Orlady and H. Clavton Foushec

(d<. ) (hloffett Field, CA: N’ationol Aeronautics and Space Administration, Ames Rmearch Center, 1%7), p. 178.

“John A. Wilhelm, The Llnlvers[ty of Texas at Austin, personnel

communication, Fch. 9, 1988.

not fly a B-727 unless he first receives a full course

of instruction, passes a written and flight examination, and is granted a “type rating” for the B-727.

Type, as used with respect to pilot ratings, “. . .

means a specific make and model of aircraft, including modifications thereto that do not change its handling or flight characteristics, . . .“19

Common type ratings of derivative aircraft offer

economic advantages to airlines and manufacturers

alike. It is much less expensive for a manufacturer

to obtain FAA certification for a derivative than

for a new type, since only modifications need close

scrutiny. One benefit is that manufacturers are able

to offer aircraft innovations to the airlines without

developing totally new aircraft. For example, new,

technologically-advanced B-737s and DC-9s, (MD80 series) are covered by type ratings issued in the

1960s (supplemented by pilot training on the modifications).

The manufacturing emphasis on derivatives refleets their popularity with airline management. Fleet

expansion by derivatives instead of different types

usually permits lower crew training costs: less time

is required to train pilots in multiple models and

new simulators are not necessary. Single type fleets

also enable greater flexibility in crew scheduling. The

importance of type considerations is reflected in the

1“14 CFR 1.1 ~an. 1, 1987).
124

fact that the only new aircraft types introduced by

a U.S. manufacturer in the 1980s are the B-757 and

B-767, and they have a common pilot type rating.

The safety and economic issues at stake over type

ratings have caused considerable controversy. FAA

certificated the DC9-80 (MD-80) with a two-person

crew, instead of the customary three-person crew,

in August 1980. However, this caused such contention that a Presidential Task Force had to be established. The report of the Task Force affirmed the

FAA decision. The main point of discussion among

the manufacturers, FAA, and the pilots unions still

centers around when two different aircraft versions

are the same type. While handling and flight characteristics are the only type criteria in current regulations, cockpit changes are a substantial human

factors concern. However, cockpit certification does

not receive the level of quantitative analysis by FAA

as do other aircraft component certifications. Effectively, the cognitive aspects are considered by using

subjective assessments of flight crew workload based

on the judgment of test pilots who rate a new cockpit

as “better” or “worse” than a comparable one.

Quantitative engineering evaluations, such as the

performance criteria used for engine designs, are not

feasible for many aspects of modern cockpits.20

Currently, FAA is developing new standards for

determining separate type ratings. Cockpit design

and pilot training will be prime considerations in

an FAA advisory circular, which is to be issued for

public comment in 1988.

Advanced Cockpit Technology

Automation.–"Automation,” or assigning to

machines or computers physical or mental tasks previously performed by the crew, is a frequently cited

means of reducing human error. While totally eliminating humans from the operational loop is not yet

feasible nor necessarily desirable, partial replacement

is becoming increasingly common. Theoretically,

automation minimizes or prevents operational human errors by reducing the physical or mental workload of the human operator, or by eliminating the

human from an operational control loop. Used

appropriately, automation is a valuable tool; the autopilot, a flight-path control device, is one such item.

Automated devices can provide for more efficient

and precise flight operations, but they also require

monitoring and proper setting, areas where people

can and do make errors. For example, digital navigation equipment is susceptible to keyboard entry

or “finger errors. ” Such errors can easily go unnoticed by the crew; it is believed that KAL 007 flew

off course because of a keyboard error. z

’ A broader

‘(’U.S. Department of Transportation, Federal Aviation Administration, Aviation Behavioral Technology Program: Cockpit Human

Factors Research Plan (Washington, DC: Jan. 15, 1985), pp. 20-21.

“Earl L. Wiener, “Beyond the Sterile Cockpit,” Human Factors, tel.

27, No. 1, February 1985, pp. 75-90.

Photo credit: Boeing Commercial Airplane Co.

In modern cockpit designs (left), electronic displays replace many electromechanical instruments (right), as shown in

these photographs of Boeing 747 cockpits.
125

problem is that automatic devices are often installed

one item at a time, especially in older aircraft, without the consideration of the overall pilot-cockpit

system.

There are no FARs relating cockpit automation

to human performance, and no real expertise within

FAA, to address this issue. For example, the advanced cockpit electronic systems on the Boeing 757

and 767 airplanes required an “equivalent safety”

deviation from current regulations to be certified.22

Automatic devices for the cockpit, which have subtle effects on human performance, are treated the

same as other pieces of hardware in the regulations.

Human error hazard analyses are not required in

the design, test, or certification stages.23 Some

basic standards for cockpit design are included in

FARs, but they do not address technological developments of the past decade such as CRT displays

and flight management systems. For example, although the use of color has increased in modern

cockpit devices, FAA has set standards only for

warning, caution, and advisory lights. There are no

rules governing other uses.

Participants at OTA’s Workshop on Human Factors in Commercial Aviation Safety stressed that

the use of automation will only increase, and most

believed that FAA is unprepared to handle current

and future automation issues. The role of the human in an increasingly automated environment

needs to be studied and bases established for setting standards. ATC is also likely to be increasingly

automated. Box 6-A describes automation programs

now being planned.

Air-to-Ground Communication.—Verbal communication remains the weakest link in the modern aviation system; over 70 percent of the reports

to ASRS involve some type of oral communication

problem related to the operation of an aircraft.24

Technologies, such as airport traffic lights or data

link, have been available for years to circumvent

some of the problems inherent in ATC stemming

~

: Delmar M. Fadden, Boeing Commercial Airplane Co., Office of

Technology Assessment, op. cit., footnote 2.

‘]C.O. Miller, a\iation consultant, personal communication, Feb.

13, 1988.

‘

+ Ralph L. Grayson and Charles E. Billings, “information Transfer

bet~een Alr l_raffic Control and Aircraft: Communication Problems

In Flight Operations, ” NASA Technical Paper 1875, September 1981,

PP. 47-61.

Box 6-A.-Air Traffic Control Automation

One aspect of the National Airspace System

Plan, the Advanced Enroute Automation System

(AERA), could bring sweeping job changes for air

traffic controllers through automation. AERA is

software to be introduced in three stages as part

of the Advanced Automation System (AAS), the

Federal Aviation Administration’s (FAA) planned

upgrade to the entire air traffic control system (see

chapter 7). The effectiveness of automation in accomplishing job tasks and the consequences of individual controller performance differences is being studied at the Civil Aeromedical Institute. FAA

plans to study controller selection and training requirements for AERA. An FAA contractor has

built and installed prototypes of portions of AERA

algorithms in a simulation laboratory. Used for

subjective evaluations of controller interactions

with automation, this initial test system does not

have enough realism for quantitative efficiency

measurements. Controllers taking part in the testing provide their views on the utility of the automated aids and the nature of inter-controller coordination in the advanced environment. FAA

plans to quanify the benefits of AERA in real-time

evaluations once the AAS contractor has installed

hardware at the FAA Technical Center (scheduled

for 1994). At present, there are no firm plans for

AERA hazard analyses, and data gathering for the

real-time evaluations has not been articulated.

from verbal information transfer. (For more information on communications technologies, see chapter 7.) The ground collision between two B--747 aircraft in Tenerife in 1977, resulting in the greatest

loss of life in an aviation accident, occurred because

of a communication error.

One potential problem with ATC by data link

is that the loss of the “party line” effect (hearing the

instructions to other pilots) would remove an important source of information for pilots about the

ATC environment. However, the party line is also

a source of errors by pilots who act on instructions

directed to other aircraft, or who misunderstand instructions that differ from what they anticipated by

listening to the party line. Switching ATC communication from hearing to visual also can increase pilot workload under some conditions.25 Further

‘~Fadden, personal communication, op. cit., footnote 22.
126

study is necessary to define the optimum uses of

visual and voice communications.

Management Practices

The judgment and skill of the pilots, mechanics,

air traffic controllers, and other key people in the

aviation system are influenced, to varying degrees,

by management decisions. While many aspects of

human behavior fall outside the sphere of management and are an inescapable part of a highly

demanding and complex system such as commercial aviation, some depend on how the system is

organized and operated. For example, airline management practices regarding pilot selection and training, as well as aircraft design, provide the underpinnings of pilot performance. A considerable

amount of public debate has focused on airline operational pressures and employee stress.

The terms “stress” and “fatigue” are commonly

used in everyday discourse, but with widely varying meanings and contexts. A “stress factor” is a

physiological or psychological pressure or force acting on a person which compels him to act or react,

physically, cognitively, or emotionally. Examples of

stress factors in aviation range from noise, vibration, and glare in the cockpit, to anxiety over

weather and traffic conditions, to anger, frustration,

and other emotions. Chronic stress degrades performance and decisionmaking, and the overall effect of multiple stresses is cumulative. Another product of cumulative stress is fatigue, which can also

result from inadequate rest, too much cognitive

activity, increased physical labor, or disruption of

physiological rhythms.26

Stress is difficult to measure in an operating environment, and little clinical evidence is available on

the cause-and-effect relationship of stress, especially

psychological or social stress,27 with performance

ability. Concern about stress is not new: workload

and duty shift conflicts, ATC and weather delays,

and labor/management problems are traditional occupational stresses in commercial aviation. However,

developments since deregulation have exacerbated

~dH. Clayton Foushee, Aerospace Human Factors Division, National Aeronautics and Space Administration—Ames Research Center, in Influence of Training, Operational and Maintenance Practices

on Flight Safery, op. cit., footnote 1, pp. 149-164.

~TCary L. Cooper and Stephen Sloan, “Occupational and Psychosocial Stress Among Commercial Aviation Pilots,” Journal of Occupational Medicine, vol. 27, No. 8, August 1985, pp. 570-576.

many of the environmental stress factors. Record

amounts of commercial traffic, increased use of hub

and spoke systems, crowded airspace and airport

ground facilities, and the resulting schedule pressures

have taken a toll on pilot, mechanic, and air traffic

controller morale and, in some cases, performance.28

Schedule pressure is a function of the whole airspace system as well as of individual airline practices. Management attitudes, especially labor/management relations, determine how schedule pressure

is interpreted in the cockpit and on the flight line.

Additionally, airline mergers frequently have resulted in divisive seniority and pay scale arguments

among management and the merging work forces.

Cockpit crews comprised of pilots holding opposite

views on unresolved merger issues bring additional

stress to commercial flight operations.

Virginia Polytechnic Institute and State University, under contract to ALPA, is studying stress and

its effects on airline pilots. One purpose of the research is to compare pilot populations from different carriers and to determine differences based on

established psychological measures of stress. Surveys

were conducted in July 1986, at one “unstable” and

two “stable” major airlines. For this survey, the unstable airline was one that was sold, merged, or taken

over in a 12-month period, had a net loss for the

last two earning periods, and had employee wage/

work rules concessions in the last contract. The pilots from the unstable carrier, with a long history

of labor-management problems and its recent acquisition by another carrier, presented a distinctly

different stress profile than the other pilots. While

55 percent of the stable airline pilots exhibited none

of the high stress measures (such as low self-esteem,

depression, and physiological indications), only 10

percent of the pilots from the unstable carrier

showed no high stress. Additionally, 30 percent of

pilots from the unstable airline indicated high stress

on 4 or more stress measures as compared with only

5 percent of the pilots from the other airline. The

stress profiles were so dissimilar among the airlines

that 90 percent of the pilots who expressed high

stress symptoms could be correctly identified by carrier affiliation.29

~BOTA, primary research, 1987.

~gLinda F. Little, Virginia Polytechnic Institute, testimony before

U.S. Congress, House Committee on Economic Stabilization, Subcommittee on Banking, Finance and Urban Affairs, May 12, 1987, and

Linda F. Little, Virginia Polytechnic Institute, “The Pilot Research

Project: 1987 Data,” unpublished data.
127

Airline operating safety is based upon well-rested

and alert flight crews. An analysis of ASRS data

revealed that about 4 percent of crewmember error

reports were directly associated with fatigue, and 21

percent mentioned factors directly or indirectly related to fatigue. 30” NASA-Ames currently has a

comprehensive program underway to examine fatigue-related problems in short-haul and long-haul

commercial and military flight operations. Already

completed, the short-haul phase of the study examined flight crews before and after they had completed

a 3-day, “high-density” trip, The findings illustrate

the complexities involved in analyzing human performance. The post-duty crews, by all measures,

were more fatigued than the pre-duty crews. However, the more tired post-duty crews performed significantly better and made fewer errors during the

laboratory simulator sessions. The study concluded

that flight crew communication and coordination

patterns were largely responsible for the performance differences, Recent operating experience and

crew familiarity can override fatigue factors in some

short-haul operations. 31

FARs, ostensibl y addressing crewmember fatigue,32 are silent on items such as pilot duty-time,

considered crucial in other countries. Some experts

believe that duty-time, the time spent in-flight, and

on the ground for preflight, postflight, and between

flight stages, is a superior measure for evaluating fatigue in air transport operations.33 An analysis of

the aviation regulations for nine industrial nations

shows that only the United States and France do

not explicitly consider pilot duty -time.34 FAR work

rules also do not consider the number of takeoffs

and landings performed, the number of time zones

crossed, and whether crew rest immediately precedes

flight duty, issues considered important in many

other countries.35

‘“R. Curtis Graeber, “Sleep and Fatigue in Short-Haul Flight Operations: A Field Study, ” Flight Safety Foundation Proceedings, op. cit.,

footnote 1, pp. 142-148.

‘

] Foushee, op. cit.,footnote 26, pp. 149-164.

‘J50 Fecleral Register 29306 (July 18, 1985).

“Hans M. N’egmann et al., “Flight, Flight Duty, and Rest Times:

A Comparison Between the Regulations of the Different Countries,”

A ~’[arlon, Space, and Environmental Medicine, March 1983, pp.

212-217.

‘

+ Ibid.

“The Federal Aviation Regulations (14 CFR 12 1.47) address duty

time by exception: the minimum rest period a crewmember must have

during anv consecutive 24-hour period is 8 hours, implying an allovable duty period of up to 16 hours.

Federal Responsibilities

Throughout the history of aviation, safety improvements have come primarily from technological developments, such as reliability and performance increases in aircraft, navigation devices,

weather forecasting, and ATC, FARs emphasize,

with more precise standards, the technical aspects

governing aircraft operations and certification rather

than the human factors considerations. Although

some human factors-related data collection, analysis, and research are supported and conducted by

the Federal Government, FAA has requested little

that can be applied to regulatory decisionmaking.

FAA does not have a centralized and systematic approach to improving flight crew performance. 36

DOT (primarily FAA), NTSB, and NASA are the

Federal agencies involved in civil aviation human

factors.

FAA

FAA, and its predecessor the Civil Aeronautics

Authority, have addressed numerous human behavior issues through guidelines and oversight.

Many Federal regulations and advisories reflect efforts to prevent human error, although few of these

rules are based on proven scientific principles. Timetested procedures and regulatory experience are valuable background data for setting human factors

standards, but as discussed in the previous sections,

technological and managerial developments in commercial aviation have outpaced FAA’s regulatory

capacity. Pilot selection and training rules have not

been substantially revised in decades, and cockpit

design requirements ignore much of the current human factors knowledge.

FAA, recognizing the importance of human factors in aviation safety, has sponsored several workshops, conferences, and studies on human performance in aviation. However, none of these efforts has

resulted in major policies, programs, or rules. The

President’s Task Force on Aircraft Crew Complement recommended in 1981 that FAA support and

expand a number of human factors-related research

areas. 37 By 1985, FAA had developed a Human

Factors Research Plan comprised of 23 research

‘Federal Aviation Administration, op. cit., footnote 20, p. 6.

‘;The President’s Task Force on Aircraft Crew Complement, “Report of the President’s Task Force on Aircraft Crew Complement,”

unpublished manuscript, July 2, 1981, pp. 8-12.
128

projects to address a number of cockpit- and pilotrelated problems.38 Because of austere budgets and

the 2-year cycle for initiating new projects, few of

its projects were initially funded. However, by 1987,

18 of the 23 projects had received some funding from

FAA or other Federal agencies and 1 was completed.

Additionally, the Transportation Systems Center

was tasked under a project agreement with FAA to

update the plan and publish a revision.

However, the underlying reasons for limited past

FAA action on human factors still exist; FAA has

never devoted the resources necessary to deal objectively with human factors issues. The Office of

Flight Standards, responsible for establishing and

enforcing air carrier operating regulations, has one

person assigned as a human factors coordinator but

no separate organizational element with human factors responsibility.

Regulatory policy must be supported as well by

documented data and research findings. As discussed in chapter 4, FAA’s data collection and analysis efforts could be revised to provide support for

human factors research. Although FAA conducts

and supports research projects on human factors in

ATC, it has only recently devoted staff or budget

for efforts in cockpit human factors. While a regulatory agency such as FAA need not necessarily undertake a substantial amount of fundamental research in any technical field, including human

factors, it must have access to up-to-date scientific

and technical research results so as to exercise timely

judgment on technical issues. To do so, FAA needs

trained staff to define and manage FAA-supported

research efforts, to analyze and interpret findings,

and to review and promulgate regulations.

Staff shortages are compounded by coordination

difficulties inherent in the FAA management structure. Human factors responsibilities are spread piecemeal throughout FAA and the Department of

Transportation. While cockpit-related research

projects are managed under the Associate Administrator for Development and Logistics, primarily by

the Program Engineering and Maintenance Service, the impetus must formally be provided by the

Associate Administrator for Aviation Standards

(AVS). For example, FAA’s Transport Aircraft Certification Division, located in Seattle and responsible for approving commercial transport cockpit designs, cannot task the Program Engineering and

Maintenance Service directly, but must pass all requests through AVS.

The Office of Aviation Medicine and its Civil

Aeromedical Institute (CAMI) provide data upon

which AVS can base regulations and advisories.

However, most of the human behavioral studies at

CAMI’s Aviation Psychology Laboratory are directed toward ATC.39 The effectiveness of another

regulatory research source in human factors for

FAA, the Transportation Systems Center, is diminished by the bureaucratic entanglements that result

with inter-administration projects.

AVS collects and maintains field data, such as

accident and incident reports and air carrier inspection findings, that could support human factors

rulemaking. However, these data management efforts have provided few safety analyses. Additionally, the Office of Aviation Safety, located in yet

another division and responsible for broad safety

studies, has undertaken no recent human factors

analyses.

NTSB

Human factors receive a great deal of emphasis

in NTSB investigations of major accidents, the resulting determinations of probable cause, and recommendations for future accident prevention.

NTSB has a separate Human Performance Division

within its Bureau of Technology and usually includes

a human factors specialist on each major accident

investigation team. Report forms, interviews, and

analytical techniques are designed to elicit detailed

information on the performance of the people involved in the mishap and the environmental and

operating conditions that were present.

NTSB accident database management and analyses are critically important, for they provide the

only valid statistical safety trends currently available to the Federal Government (see chapter 4).

While lessons can be learned from individual accidents, the greatest understanding comes from analyses of clusters of accidents. For example, the

frequent occurrence of flight crew coordination

18Federa] Aviation Administration, Op. cit., footnote 20. ‘91bid, p. 112.
129

problems in accidents has resulted in numerous

NTSB recommendations urging the use of cockpit

resource management training. 40

NTSB analyses are sometimes published in detailed special studies, covering such topics as runway incursions, airport certification and operations,

and commuter airline safety. However, NTSB has

not undertaken a comprehensive analysis, and has

published no special studies on human factors in

aviation.

NASA

NASA has traditionally provided a substantial

amount of fundamental aviation research. For human factors in civil aviation, NASA contributes a

major share of research, supplemented only by applied research programs in industry and basic research at a handful of universities. NASA is in a

unique position which enhances its human factors

research efforts. While maintaining close working

relationships with FAA, NTSB, the military, and

the commercial aviation industry, nonregulatory

NASA is viewed as an impartial party. This gives

NASA access to sensitive data unavailable to other

Federal groups.

“John K. Lauber, National Transportation Safetv Board, “Cockpit

Resource Management: Background and O\’erview,” Cockpit Resource

.tianagernenr Tra{nlng, op. cit., footnote 17, p. 12.

Photo credit: National Aeronautics and Space Administration

Researchers investigate the effects of future cockpit

technology on human performance with the Advanced

Concepts Flight Simulator at NASA-Ames

Research Center.

Two research centers within NASA, Ames in

California and Langley in Virginia, are responsible

for most of the human factors work. Generally,

NASA-Langley investigates the physical aspects of

human factors, while NASA-Ames studies the psy

-

chological elements. Physiological measures of pilot workload and advanced cockpit displays are

among the topics addressed at Langley. The operational implications of human factors research—cockpit resource management, information transfer, sleep

cycle and fatigue, and the effects of advanced automation on flight crew performance—are important

fields of study at NASA-Ames. For example, LOFT

was developed from the use of full-mission simulation as a research tool at Ames.

NASA-Ames also administers the Aviation Safety

Reporting System, the only broad source of human

factors field data other than NTSB investigations

available to the Federal Government. However, effective use of ASRS data has been hampered in recent years by level funding in the face of increasing

reports, resulting in resources being diverted from

analysis to processing. NASA-Ames increasingly has

become the human factors information clearinghouse. 4l While all databases have limitations,

ASRS analyses could provide information unavailable to FAA from other sources, such as the influence of new technologies or airline management

practices on human performance.

Industry Responsibilities

Airlines and aircraft manufacturers regard safet y

seriously, giving clearly indicated safety problems

quick and thorough attention. Understandably,

however, industry rarely undertakes voluntary

safety-oriented improvements unless the link between the improvement and safety is clearly established. FAA, as the regulatory agency, must shoulder primary responsibility for the absence of human

factors standards.

The lack of objective cockpit certification standards is a case that illustrates how human factorsrelated decisions are made (or not made). According to one NASA official, most of NASA’s fundamental civil aviation research efforts have focused

on areas such as aerodynamics, propulsion, avionics,

+ ‘Graeber, op. cit., footnote 2.
130

and materials. Less emphasis is placed on human

factors, since aircraft manufacturers do not consider

human factors to be a technology that controls

whether an aircraft design is feasible or not. The

manufacturers cite airline concerns with reducing

operating costs through better fuel efficiency and

lower maintenance expense. The airlines do not usually question FAA-approved cockpit designs or

other FAA-certified components, such as engines.

FAA completes the circle, stating that no data are

available, such as research findings from NASA, to

justify establishing cockpit certification standards.42

This is not to say that the private sector has not

done its best to ensure that cockpit designs are safe.

Through Society of Automotive Engineers committees, industry groups (partially funded by FAA and

other Federal agencies) have established some cockpit design standards. Compliance with these voluntary standards has traditionally ensured FAA approval of designs.43

Economic considerations play a major role in

cockpit layout decisions. For example, a number of

recent advances in cockpit technology have been

driven by airline cost savings. Two-person v. threeperson crew complements reduce salary expenses;

common type ratings save on training and scheduling costs; automation allows more efficient and precise flight path control; and solid-state avionics have

lower maintenance costs than electromechanical

devices. “While no reputable manufacturer knowingly compromises safety for short-term cost savings,

clear, comprehensive Federal requirements are important in assuring that no actual compromise in

safety occurs. ”44

Moreover, OTA finds that a systems approach

is needed for cockpit certification. While FAA can

adequately ensure that a given cockpit design is not

unsafe, the cross-effects of pilots flying in multiple

cockpit versions has not been sufficiently addressed.

The effects of standardization in cockpit design on

pilot performance need to be more fully examined

and documented. Additionally, certification approval of vastly different cockpit designs has been

criticized by at least one U.S. aircraft manufacturer.

4%usan Norman, National Aeronautics and Space Administration,

Ames Research Center, personal communication, Nov. 19, 1987.

q ‘Fadden, op. cit., footnote 22.

~~De]mar M. Fadden, persona] communication, Mar. 1 ! 1988.

Boeing based cockpit display designs on its research

into color visibility in electronic displays. The research findings conflict directly with the color standards used for Airbus cockpits, yet FAA approved

both standards.45

The airlines are left with the responsibility of accommodating differing cockpits. One option, purchasing uniform fleets, is rarely feasible. Different

aircraft requirements for different markets, as well

as mergers and acquisitions, have left airlines with

diverse fleets. Training is the approach used by the

airlines and approved by FAA to prepare pilots for

these different aircraft. Provided he or she has the

required training, a pilot can fly any number of

different aircraft in revenue service, even in a single day. However, in present airline operations, very

few pilots need to stay current in two or more aircraft that have separate type ratings.46

Innovations in training are readily accepted by

airlines, provided that the costs are not prohibitive.

Advanced simulators allow greater flexibility and

safety and have become the preferred mode in training, and they also offer substantial cost savings.

Cockpit resource management training has been

adopted by a number of airlines.

Airline management has the responsibility of addressing the human factors problems that have

arisen due to operating practices and management

attitudes. Some airlines have employee assistance

and counseling programs and provide for good communication in both directions along the chain of

command. Others have conducted internal safety

audits. The recent spate of mergers provides a laboratory for comparing the effectiveness of differing

airline management practices. A number of U.S.

airlines provide open access for NASA-Ames research.47

TWA established internal safety teams and conducted audits in 1976, 1980, and 1986. The teams,

composed of line pilots and management personnel, were granted immunity from revealing information sources, and top management gave them

permission to examine all areas of flight safety. As

+5 Fa&jen, op. Cit., footnote 22”

‘

b

Ibid.

‘~R. Curtis Graeber, National Aeronautics and Space Administration Ames Research Center, personal communication, Mar. 2, 1988.
131

an outcome of the audits, TWA has instituted periodic labor-management safety meetings. The sterile cockpit concept,48 now a Federal regulation,49

came out of these TWA meetings, Additionally,

TWA has instituted a nonpunitive program for

monitoring flight data recorder approach information. Notably, while the program receives the support of TWA’s pilots, in-flight monitoring is anathema to pilots at most other carriers. Airlines that

carry out safety audits may find the process as important as the product. Employee perception that

management recognizes and is addressing a problem can play a large part in the resolution of the —

problem. 50

‘3Durlng critical phases of fllght (below 10,000 feet and all ground

operations), crewmcrnbers can perform only those duties required for

the safe operation of the aircraft. For example, extraneous conversation, including pointing out sights of interest to passengers, is prohibited.

“14 CFR 121.542 (’Jan. 1, 1987).

‘rJ.A. McIntyre, Airline Pilots Association, in Znfluence of Training, Operational and Malntertance Practices on Flight Safety, op. cit.,

footnote 1, pp. 118-124; and J.A. McIntyre, in Office of Technology

Assessment, op. cit., footnote 2.

Labor’s Role

Organized labor has an important role in the resolution of management-related human factors problems, and union contracts or initiatives often address issues not covered by Federal policy. For

example, some pilot contracts establish duty-time

limits, since FARs are not explicit in this area, and

while FARs permit Part 121 pilots to fly 100 hours

per month, few actually do.51 Additionally, labor

organizations provide publications, training programs, counseling sessions, and communication

channels to management for member employees.

Unions also support independent studies and research efforts, such as ALPA’s stress survey, and

ALPA has safety councils at each of its member

domiciles.52 For further discussion of labor-related

issues, see chapter 2.

‘lOTA primary research, 1987.

jJIbid.

CONCLUSIONS AND POLICY OPTIONS

People are pivotal to aviation safety. While humans are largely responsible for commercial aviation’s excellent safety record, human errors nonetheless cause or contribute to the vast majority of

accidents. Moreover, the rate of pilot error accidents

shows no sign of abating, while weather-related

crashes are declining and aircraft component failures

are rarely the sole factor in serious mishaps. Furthermore, accident and incident data analyses indicate that if only a portion of human error problems can be resolved, substantial reductions in

accident risk can be attained.

Changes in aircraft technology and operating

practices occurring during the past decade have

widespread human behavior and safety implications

that are poorly understood. OTA concludes that

human factors concerns regarding cockpit automation, pilot selection and training, and airline

management are not addressed adequately by current FARs.

Human factors is a fundamental technology that

is as essential to the safe design and operation of

aircraft as are aerodynamics, structures, and propulsion. However, human error hazard analyses are not

presently a normal part of aircraft or ATC system

design or certification. While the aircraft manufacturing industry and some airlines conduct human

factors research, and will continue to do so, this research is fragmented, and the results are not always

widely available.

OTA concludes that long-term improvements in

aviation safety will come primarily through systematic operational human factors solutions and

that such solutions will be found only with consistent, long-term support for research and development. Furthermore, without Federal backing,

human factors research and application will lam

guish for proprietary reasons.

FAA could make good use of the multidisciplinary human factors knowledge that is spread

throughout the Federal Government, private industry, and independent research groups if it had the

organizational structure to coordinate this understanding. For example, in 1985, FAA’s Cockpit Human Factors Research Plan drew upon the widespread expertise in the United States and proposed
132

a number of important projects; however, few received sufficient FAA funding. While FAA, as a regulatory agency, might not be expected to conduct

much research in-house, FAA must address commercial aviation human factors issues in clear, precise advisory circulars and regulations. Congress

may wish to direct FAA to allocate the resources

for human factors expertise in regulatory support

staffs, and to establish an agency focal point, such

as a Program Office, that could serve as a catalyst

and coordinator for cooperative efforts spearheaded by NASA, and including other FAA offices, NTSB, the Department of Defense, manufacturers, airlines, and unions.

The following are key areas and questions for federally supported research or regulatory efforts:

• Operational data collection. Ideally, regulations

are based upon objective evidence from the

operational environment, one area where the

field of human factors is lacking. Federal and

industry cooperation is necessary for establishing human performance measurement techniques and for ensuring proper control and dissemination of these sensitive data. Cockpit

voice recorders, flight data recorders, and video

systems could supply much of these data, provided a nonpunitive approach is taken with

close union oversight and support.

●

●

●

Physiological and psychological factors. What

are the effects of stressors, singly or in combination, on pilot and controller performance?

Advanced technology is changing the roles of

pilots and controllers; what cognitive and personality traits are desirable for the operators of

current and future aviation systems? What factors influence pilot and controller decisionmaking and what options are available for improving it? How applicable are current age and

medical requirements?

Crew management. How can crew coordination be improved? Should CRM training be federally mandated? What technology, procedures,

or training methods are available for facilitating intra-cockpit and air/ground communication?

New technology. It is possible to automate most

of the flight deck and ATC functions currently

performed manually by pilots and controllers;

however, not all automation enhances safety.

What is the optimal distribution of tasks between operators and automated systems? How

can pilot and controller readiness to respond

to emergencies be enhanced? What standards

are required to ensure effective information

transfer to the pilot or controller? How can

ATC/cockpit communication be improved? To

what extent should flight crewmembers be monitored by automated systems?
Chapter 7

Air Traffic System Technologies

Photo credit: Federal Aviation Administration

An FAA Air Route Traffic Control Center
CONTENTS

Page

Elements of the Air Traffic System .

Models for Evaluating Changes to

Airports. . . . . . . . . . . . . . . . . . . . . . .

Airspace . . . . . . . . . . . . . . . . . . . . . . .

The National Airspace System Plan

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .135

the Air Traffic System . ....................135

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 137

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 139

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 139

Air Traffic Control Hardware and Software . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .140

TRACON Improvements. . . . .

Training Air Traffic Controllers

Collision Avoidance Technology

Ground Collision Avoidance .

Communications . . . . . . . . . . . . . .

Navigation . . . . . . . . . . . . . . . . .

Surveillance. . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .143

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 146

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 147

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 148

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 150

...,.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 153

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 154

Weather Technologies and Training . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ....155

Windshear . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ......................155

National Weather Service . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ................157

Air Traffic Control Role . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ...............157

Weather Research and Development. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. ...158

Liability Issues.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..........................159

Conclusions and Policy Options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..........159

Figures

Figure Page

7-1.Air Traffic Control on a Typical Commercial Flight .. ......................141

7-2.Locations of Air Route Traffic Control Centers . ...........................142

7-3.Terminal Areas Where Radar Coverage is Provided . . . . . . . . . ................144

7-4.Locations of TRACONS With ARTS-IIIA and ARTS-IIIE Equipment. . .......145

7-5.Locations of Airport Surface Detection Equipment Radars . . . . . . . . . . . . .......150

7-6.Windshear Accidents and Incidents Before and After LLWAS Implementation .158

Table

Table Page

7-1.Status of Major National Airspace System (NAS) Plan Projects . ..............140
Chapter 7

Air Traffic System Technologies

The Federal Government’s major operating

responsibilit y for aviation safety lies in its management of the air traffic system. This system has many

individual, interdependent components, each of

which affects the safety and capacity of the overall

system. Significant components of the current air

traffic system are: 1 ) airports, 2) air route structure,

3) the air traffic control (ATC) system, including

hardware, software, and the humans who operate

and maintain the system, and 4) communications.

Any increase in capacity in one component of the

system (e.g., airports) must be accompanied by adequate capacity in the other components for it to

have an effect on overall system capacity. In dayto-day operations, the Federal Aviation Administration’s (FAA) Central Flow Control uses weather

technologies to predict airport capacity, and holds

aircraft on the ground when the predicted demand

on a destination airport exceeds its capacity in bad

weather. Other components of the air traffic system include navigation and surveillance systems, as

well as collision avoidance technology currentl y under development to back up the ATC system.

Recent growth in commercial air traffic has exerted pressures on several parts of the air traffic system. For example, air traffic levels have grown enormousl y since deregulation without a comparable

increase in airport capacity, Moreover, ATC centers

must operate using aging equipment and some do

not have enough adequately-trained personnel. The

hub and spoke system of airline operations has

“loaded” hub airports with traffic, causing traffic

levels to peak sharply at certain periods during the

day and increasing schedule disruption when a flight

is canceled or delayed because of weather, equipment malfunction, or any other reason.

If demand for air transportation continues to increase and no actions are taken to address capacity

issues, delays will increase and the high level of safety

now maintained by the ATC system may deteriorate. Because of the complexity of the system, particularly the human element, it is extremely difficult

to determine precisely at what point deterioration

would occur.

This chapter examines the potential of technology to mitigate the stresses on the air traffic system

and to improve its safety, including technologies or

procedures that could increase or better utilize the

capacity of the system. It also reviews prospects for

technologies to improve communication between pilots and controllers in high-density airspace. Finally,

it examines technologies to detect and communicate weather conditions to pilots, training to help

pilots use the information effectively, and navigation and surveillance systems for controlling aircraft.

ELEMENTS OF THE AIR TRAFFIC SYSTEM

Models for Evaluating Changes to

the Air Traffic System

FAA uses models and other means to evaluate

how changes in procedures, facilities, technology,

and personnel could affect safety and capacity of

the air traffic system. However, the mathematical

and computer models described below are rough

tools; decisions must still depend on astute judgment

of humans familiar with the modeled situation.

Risk Models for Procedural Changes.–FAA

normally evaluates the safety impact of procedural

changes on the basis of operational judgment, supplemented by models of “worst-case” scenarios and

other analytical tools. ] However, this approach

does not always relate procedural changes to any

objective measure of accident risk. FAA and the International Civil Aviation Organization have developed mathematical models to estimate an upper

IFor example, see A.L. Haines and W.J. Swedish, The MITRE

Corp., “Requirements for Independent and Dependent Parallel Instrument Approaches at Reduced Runway Spacing,” Report No. FAAEM-81-8, prepared for the U.S. Department of Transportation, Federal A\’iatlon Admimstratlon, May 1981.

135
136

bound to the risk of oceanic collisions and accidents

due to obstructions near the airport. The United

States is considering a change in separation standards for the North Pacific based partially on the results of risk modeling performed at FAA’s Technical Center. Also, traffic levels across the Atlantic

are monitored, and if the traffic levels exceed a

threshold determined by the risk model, FAA may

intervene and change separation standards. The collision risk model for obstructions is used by FAA,

for example, in cases when obstacles, such as tall

buildings, encroach on airspace close to runways.

Currently, FAA does not have risk models to use

in its evaluations of procedural changes in the terminal area, such as the recent reduction in minimum instrument flight rules (IFR) separation standards for certain aircraft types. FAA’s monitoring of

operations under the new standards has not revealed

operational problems that would cause FAA to revert to the original separation standards. However,

because aircraft accidents are exceedingly rare, a

huge number of observations over a number of years

would be necessary to identify a rise in risk because

of this change. A risk model for the terminal area

would also suffer from lack of data on low-probability events. For this reason, risk models, no matter how well constructed, are not adequate in themselves for evaluating the safety impact of procedural

changes in the terminal area. However, quantitative risk models for the terminal area could, if properly developed and used in conjunction with an

assessment of the impact of human error, contribute to the evaluation of procedural changes. FAA

is beginning to build a terminal area risk model at

the Technical Center. Support for development of

the model and for thorough external review of the

model by risk experts in other industries, such as

the nuclear industry, would help make available a

potentially useful, but limited, analytical tool.

System Capacity Enhancements

FAA estimates the potential benefits from new

terminal airspace control procedures, terminal ATC

automation, and construction of new runways based

on a model relating total yearly flight delay hours

at any airport to the number of air carrier and other

operations, IFR and visual flight rules (VFR) capacity, and the percentage of time that IFR conditions

prevail during a year. The model was developed from

data available from 32 airports for 1983 and 1984,

and from 10 airports for 1985. Enhancements are

evaluated by estimating the increase in IFR capacity at each airport where the enhancements could

be applied using existing FAA models for airport

capacity under instrument meteorological conditions. The overall model is then used to estimate

total yearly delays, and finally, delays for all 240 airports are considered.2 The model is not detailed,

and estimates delays without regard to airline scheduling, en route ATC procedures, and routing of

traffic flows. The model can therefore be used to

suggest the approximate magnitude of future capacity problems and effects of airport enhancements

only; it is not suitable for comprehensive capacity

examination.

SIMMOD is a model which simulates aircraft

movements and controller actions. Runways and

an airspace configuration are put into the model,

airplanes are fed in, and the model keeps track of

the statistics of travel times from point-to-point, delays and fuel burn. SIMMOD was originally designed as a fuel-burn model and was only recently

adapted for capacity modeling. SIMMOD is a very

detailed model, and system capacity can be estimated

only by trying to push as many airplanes as possible through the system by trial-and-error. SIMMOD

is a useful tool for evaluating airspace reconfiguration, but it is too detailed for a system-wide statistical evaluation.

System-Wide Performance Models.–FAA is

currently involved in a modeling effort, called National Airspace System Performance Analysis Capability (NASPAC), to evaluate the system-wide implications of changes in scheduling, airport capacity,

airways, and flow control. According to current

plans, the models will evaluate airport capacity characteristics, and model traffic flows between airports,

keeping track of how delays propagate to later times.

If successful, NASPAC could be especially useful as

an analytical support tool for FAA at the FAA/Office of the Secretary of Transportation airline

scheduling meetings (see chapter 2). Beyond these

scheduling meetings, the models could provide guidance for evaluating operational and technological

2Tran~portation Systems Center, “Airport Capacity Enhancement

Plan,” DOT/FAAjCP-87-3, prepared for the Airport Capacity Program Office, Federal Aviation Administration, 1987.
137

changes to the National Airspace System (NAS),

form the basis for improved real-time capacity management decisions, and support broader policy decisions on demand management as traffic levels increase.

Airports

Although there has been considerable airport expansion in the United States since 1978, the last

major commercial airport built in this country was

Dallas/Ft. Worth, completed in 1973. Only two new

airports are definitely planned for the future; one

about 17 miles from Denver to replace Stapleton

Airport, and the other in Austin, Texas. The Denver airport would open with a minimum of six runways and would allow simultaneous IFR approach

in both the North/South and East/West directions. 3 Commercial airports take many years to

construct, so near-term relief for airport congestion

must be found in other ways. Runway capacity at

existing airports can be constructed more quickly

and approximately 18 new runways are currently

planned at existing commercial airports. Runways

planned for Nashville and Orlando may be completed as early as 1989.4

Both departures and arrivals at airports are severely curtailed by bad weather. FAA has set

weather criteria for VFR and airlines plan their

schedules for VFR weather conditions, although

commercial airlines fly under IFR regardless of

meteorological conditions. Flights are held on the

ground at departure airports by FAA’s Central Flow

Control Facility when the number of scheduled

flights exceeds an airport’s capacity to receive them

due to bad weather. Most commercial flight delays

over 15 minutes are caused by weather;5 thus,

FAA is particularly interested in procedural changes

to increase airport capacity under poor weather conditions.

Currently, simultaneous independent use of converging runways is not permitted except when the

cloud ceiling is 500 feet or more and visibility is at

least 1 mile, because of concern about simultane-

‘Wayne ]. Barlow, director, Northwest Mountain Region, Federal

Aviation Administration, letter to OTA, Dec. 22, 1987.

‘Arnold Price, deputy director, Airport Capacity Program Office,

Federal Aviation Administration, letrer to OTA, Dec. 17, 1987.

5Transportation Systems Center, op. cit., footnote 2.

ous missed approaches by both aircraft. During bad

weather, such use of parallel runways is allowed only

when the runways are at least 4,300 feet apart; dependent simultaneous use of parallel runways is permitted only when the runways are at least 2,500 feet

apart; and triple parallel runways cannot be used

simultaneously. Each of these procedural rules is being examined by FAA as part of its Airport Capacity Enhancement Plan; they could potentially be

liberalized to allow more operations under instrument meteorological conditions. Reducing requirements on runway spacing for independent parallel

IFR approaches would require a precision approach

radar and a controller position to monitor the space

between the runways–such a controller position is

always required for independent parallel IFR approaches.’ Not all airports would be affected by

these potential changes, because their applicability depends on the runway configuration at the

airport. i

FAA recently reduced minimum IFR aircraft separation standards for certain aircraft types on final

approach from 3 miles to 2.5 miles at airports with

taxiways that permit an aircraft to exit a runway

within 50 seconds of touchdown and if other conditions are met. The exit time restriction is necessary

because no aircraft is permitted to land on a runway already occupied by another aircraft. Twentyfive airports have been approved for the reduced

separation standard, and other airports may be eligible in the future if high-speed exits are built for existing runways. However, the reduction is controversial because the 50-second runway time requirement

is subject to disagreement, and because the pilot of

an aircraft trailing another by 2.5 miles has less time

to make altitude or lateral adjustments to avoid the

wake vortex of the leading aircraft, a potential problem in bad weather. Moreover, some pilots are uneasy about operating so close behind another aircraft without any means of estimating separation.

Cockpit display of traffic information, applied as

a backup to ATC, could mitigate some of these concerns. Nearby traffic has been displayed in the cockpit in tests of the Traffic Alert/Collision Avoidance

System (TCAS), although the usefulness of a TCAS

fArnold Price, deputy director, Airport Capacity program ‘ffice~

Federal Aviation Administration, personal communication, Nov. 13,

1987.

‘Transportation Systems Center, op. cit., footnote 2.
138

display on final approach has not yet been established. FAA plans to test TCAS display use during closely-spaced parallel runway demonstrations

in 1988 and 1989. Another option, which may become feasible in the future, is to send surveillance

radar data to the cockpit over data link. However,

this option raises major operational questions about

the roles of pilots and air traffic controllers in maintaining aircraft separation.

Another area of potential gain is in automation

of terminal area ATC for more efficient metering

of traffic, particularly during bad weather. FAA is

starting a program to develop automated terminal

systems for eventual implementation around the

year 2000.8

FAA has estimated the potential benefits from improved terminal airspace control procedures, terminal ATC automation, and construction of new runways (as planned in 1986) using the airport capacity

enhancement model described earlier. Although uncertainties remain, the results suggest that the improvement from enhancements cannot compensate

for the additional delays caused by projected increases in air traffic levels through 1994. Even with

all the enhancements, the projected delay per flight

would be 96 percent of its current value. The model

projects 114,500 aircraft hours saved compared to

a projected increase of 445,000 aircraft hours without enhancements.9

Some capacity gains are also possible from the

Microwave Landing System (MLS), depending on

airport runway configuration and location with respect to topographical features and other airports.

However, locally imposed airport noise restrictions

may limit the curved and segmented approaches

theoretically possible with MLS. Additional airborne computer equipment must still be developed,

and MLS will probably not significantly affect airport capacity in the near future because the current

Instrument Landing System (ILS) will be widely

available until at least 1998, and consequently not

all aircraft will convert to MLS. FAA studies suggest difficulties in controlling aircraft making curved

or segmented approaches in a mixed ILS/MLS environment. 10

‘Ibid.

‘Ibid.

“’National Aeronautics and Space Administration and Charles

Stafford, “Report on the Simulation of Microwave Landing System

Procedures In the New York Terminal Area,” unpublished report, 1987.

Greater use of existing military airports for commercial operations instead of building new airports

or additional runways can alleviate some airport capacity problems. As of 1984, there were 24 jointuse airports—military airports with agreements to

support some commercial operations.11 However,

using these airports for high-volume commercial traffic could produce local noise problems and restrict

flexibility for military flights, while security limitations could interfere with efficiency of commercial

operations. Furthermore, military airports generally

do not have sufficient facilities for conveniently handling large numbers of passengers. Finally, the total additional capacity these airports could add to

the system is limited. Thus, military airports are a

good choice to relieve congestion in some areas in

the near term, but other measures are needed to

solve the national capacity problem.

Smaller, less used civil airports could also be used

as hubbing centers. In fact, as delays at major hubs

increase, some airlines are locating hubs at smaller

airports, despite the fact that smaller cities have

fewer origin and destination passengers than larger

hubs. Smaller airports can relieve some stress on

large, crowded hub airports, but, depending on local conditions, may not necessarily assist with airspace congestion. Similar tradeoffs apply to the use

of reliever airports to receive some general aviation

(GA) traffic that would otherwise fly into busy hub

airports.

Noise and congestion problems attendant to airports near big cities have prompted proposals to

build large airports far from cities for use as hubbing centers. Using airports strictly as hubbing

centers is a radical concept by current standards,

because airlines need substantial revenues from origin and destination passengers. This situation could

change, however, if traffic levels continue to grow

and hubbing persists. FAA is currently exploring

high-speed rail or advanced vertical and short takeoff and landing aircraft for transporting passengers

rapidly from city centers to distant airports.12 AdI IThe Secretary of Defense and the Secretary of Transportation,

“The Plan for Joint Use of Military Airfields,” pursuant to section

504(d)(3) of the Airport and Airway Improvement Act of 1982, Public

Law 97-248, Mar. 8, 1984, p. 2.

‘zAlbert W. Blackburn, associate administrator for Policy and International Aviation, Federal Aviation Administration, reported at the

Fifth International Workshop on the Future of Aviation, sponsored

by the Transportation Research Board, Oct. 6, 1987.
139

vanced rapid transit could help keep commuting

times to remote airports comparable to commuting

times to large hub airports today.

Airspace

The FAA’s East Coast Plan and the developing

west coast and Midwestern airspace reconfiguration

represent attempts to reduce delays by configuring

air route structure more efficiently. While such efforts can reduce delays, they have associated costs,

including having to change ATC facilities and

retrain controllers. For example, the East Coast Plan

had a big impact on the Boston Air Route Traffic

Control Center (ARTCC), which had to be upgraded and full performance level controllers

retrained to work with the new traffic flow configuration. These activities slowed down the training

of developmental controllers needed to fill a gap in

trained personnel in the Boston Center.l3 Another

side effect of the East Coast Plan is that flights in

and out of Philadelphia have been routinely delayed

because of airspace reconfiguration. This is especially

damaging to the commuter airlines who attract customers with frequent, on-time flights.14

Airspace reconfiguration require careful analysis to minimize unintended side effects, and FAA

is implementing the East Coast Plan in phases. By

themselves, such changes cannot compensate for future increases in air traffic levels, since airport capacity is also a limiting factor. According to an FAA

estimate based on SIMMOD, the East Coast Plan

saves about 27 flight hours per day in the region

covered by the Boston ARTCC,15 or 9,855 flighthours per year. FAA projects the increase in air carrier delays between 1984 and 1994 at 445,000 aircraft hours, assuming no capacity enhancements,16

Widebody aircraft.–Several aircraft manufacturers have forecast a trend towards higher-capacity

aircraft in response to the airport congestion problem.17 The major Japanese airlines (Japan Air Lines

and All-Nippon Airways) have adapted some Boeing 747 aircraft for high-capacity short-range travel

by reconfiguring the interiors. In the United States,

however, the trend following deregulation has been

towards smaller aircraft. This could change, however, as demand for air travel increases and if airline operations shift from hub and spoke to pointto-point. Also, even though some airlines are purchasing new aircraft, others are retaining older aircraft, slowing the process of replacing smaller aircraft by larger, more expensive ones. Given the

current incentives for purchasing smaller aircraft and

continuing to use existing smaller types, it is difficult to predict how much use of larger aircraft will

actually relieve congestion. Nonetheless, widespread

use of high-capacity aircraft for medium- to longrange routes could increase system capacity significantly, particularly if combined with high-speed

ground transportation to major hubs.

1‘Char]es Peahl, assistant manager for Training, Boston Air Route

Traffic Control Center, Eederal Aviation Administration, personal communication, Sept. 9, 198?.

]+CJTA ~rimary research, 1987.

15 Price, op. cit., fOOtnOte 6.

16Transportation Systems Center, op. cit., footnote 2.

‘

i

James Ott, “Industry Foresees Wide-Bodies as Ald to Congested

System, ’’Aviation Week& Space Technology, Sept. 28, 1987, pp. 36-37.

THE NATIONAL AIRSPACE SYSTEM PLAN

The NAS Plan, developed by FAA and first published in 1981, is a comprehensive plan to modernize and improve airways and aviation facilities. The

centerpiece of the NAS Plan is the upgrading of the

ATC system to accommodate more traffic with

greater efficiency and automation. When it was first

presented to Congress, costs for the NAS Plan were

projected to be $9 billion over 8 years, but total cost

estimates which now include Terminal Doppler

Weather Radar, as well as life cycle costs not originally in the NAS Plan, have ballooned to $15.8 billion through the year 2000. NAS Plan financing is

described in chapter 3.

All the major programs in the NAS Plan are behind the original schedule by substantial amounts

(see table 7-l). Two views as to why the NAS Plan

has slipped so far behind schedule are now prevalent. The first view is that Congress has been unwilling to appropriate from the Airport and Airway

Trust Fund because the unused fund monies can be

applied against the Federal deficit, thereby allowing
140

Table 7-1.—Status of Major National Airspace System (NAS) Plan Projects

Project Slippagea Reason for slip

Host Computer . . . . . . . . . . . . . . . . . . . . . . . . . . .

Advanced Automation System . . . . . . . . . . . . .

Voice Switching and Control System . . . . . . .

Flight Service Automation System . . . . . . . . . .

Automated Weather Observing System . . . . . .

Central Weather Processor . . . . . . . . . . . . . . . .

Long-range radar (Air Route Surveillance

Radar: ARSR-4) . . . . . . . . . . . . . . . . . . . . . . . . .

Mode S . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Airport Surveillance Radar (ASR-9) . . . . . . . . . .

Microwave Landing System . . . . . . . . . . . . . . . .

Radar Microwave Link. . . . . . . . . . . . . . . . . . . . .

Terminal Doppler Weather Radar . . . . . . . . . . .

6 months

2 years

1 year

2 years

2 years

3 years

4 years

4 years

3 years

2 years

1 year

1 year

Contractor delays in software coding and documentation

Additional requirements added and provision for preproduction testing

Additional requirements (number of operational positions,

redundancy) and testing to reduce risk

Software development problems

Contractor difficulty complying with Critical Design Review

requirements and failure to perform required quality

assurance procedures

Addition of prototype phase, redefinition of statement of

work with contractor (NASA/JPL), less than optimum

contractor staffing

Delay in consummating FAA/USAF agreement on number of

systems required and funding

Prototype added, clarification of specifications, revised test

plan, contractor late meeting critical design review

Delay in completion of critical design review, problems in

system integration testing, FAA rejection of inadequate

test procedures, contractor problem obtaining critical

parts

Delay in contractor software coding

Implementation started in 1986

Revision of draft project specification, evaluation of impact

of various siting options

KEY: NASA/JPL - National Aeronautics and Space Administration/Jet Propulsion Laborato~; FAA = Federal Aviation Administration; USAF = U.S. Air Force

aAmount of slippage in initial implementation comparison 1983 NAS Plan with draft 1%7 plan.

SOURCE: Office of Technology Assessment based on General Accounting Office, 1987 and Federal Aviation Administration, letter to Off Ice of Technology Assessment,

Jan. 15, 198S

government funds for other purposes to be appropriated under the Balanced Budget and Emergency

Deficit Control Act of 1985. The second view is that

FAA has not been able to spend money on NAS

Plan procurements because of engineering problems,

particularly in software development, and changes

in technology requirements caused by unanticipated

developments in air transportation since 1981. While

both views contain elements of truth, the General

Accounting Office (GAO) contends that NAS programs have fallen behind because the original plan

did not anticipate the time needed to tailor existing technology to ATC system requirements and

did not provide time for adequate development and

testing. 18 However, delays and cost increases of the

magnitude experienced for the NAS Plan are not

unusual for large and complex technological programs throughout the Federal Government.

FAA also maintains a plan for research, development, and engineering to investigate areas of technology not covered in the NAS Plan, and to fully —.

exploit NAS Plan technologies.19

Air Traffic Control Hardware

and Software

ATC facilities at all levels—airport towers, Terminal Radar Approach Control (TRACON) facilities, ARTCCs, and the Central Flow Control Facility (see figure 7-l)—experience the stresses of high

traffic levels. The original version of the NAS Plan

called for substantial changes in ATC facilities, including automation, to handle increased traffic by

the early 1990s,20 but most of the major changes

are not now expected until the late 1990s and be18Herbert McLure, associate director, Resources, Community and

Economic Development Division, General Accounting Office, “National Airspace System (NAS) Plan Delay s,” testimony before U.S. Congress, Senate Committee on Commerce, Science and Transportation,

Subcommittee on Aviation, Apr. 8, 1987.

ITcs. Department of Transportation, Federal Aviation Administration, “The Federal Aviation Administration Plan for Research, Engineering and Development,” vol. 1, draft manuscript, August 1987.

~’?_J.S. Department of Transportation, Federal Aviation Administration, National Airspace System Plan (Washington, DC: December

1981), pp. III-8, III-9, IV-6, and IV-7.
141

Figure 7-1 .—Air Traffic Control on a Typical Commercial Flight

Airport surface detection

equipment (ASDE) radar

Airport

tower

r

Air route Air Route TRACON Arrival airport

surveillance Traffic Airport

Central

surveillance

radar Center radar

Flow Control Terminal Radar (ARTCC)

Approach

Control (TRACON)

1 2 3 4 5

KEY

1 The airport tower controls the aircraft on the ground before takeoff and then to about 5 miles from the tower, when the tower transfers aircraft control to a Terminal

Radar Approach Control facility (TRACON). Controllers in the airport tower either watch the aircraft without technical aids or use radars—Airport Surface Detection

Equipment for aircraft on the surface and airport surveillance radar for those in the air Central Flow Control (in Washington, DC) can order the tower to hold flights

on the ground If demand exceeds capacity at the arrival airport.

2. The TRACON, which may be located in the same building as the airport tower, controls aircraft from about 5 miles to about 30 miles from the airport, using aircraft

position information from the aircraft surveillance radar. The TRACON then transfers control of the aircraft to an Air Route Traffic Control Center (ARTCC)

3 ARTCCS control aircraft that are en route between departure and arrival airports. Each ARTCC controls a specific region of airspace and control is handed off from

one ARTCC to another when a boundary is crossed. Aircraft positions are detected by the air route surveillance radar. The last ARTCC on the flight path transfers

control to a TRACON when the flight is about 30 miles from the arrival tower,

4 The TRACON controls the arriving aircraft until it is within about 5 miles of the arrival airport tower, when control IS transferred to the tower.

5 The airport tower controls the aircraft on the final portion of its approach to the airport and while it is on the ground.

SOURCE Off Ice of Technology Assessment, 1988

yond.21 Automated tools for controllers can reduce

workload, provide information to reduce the

amount of potentially error-prone mental judgments

controllers now must make, permit better teamwork,

and enhance the working environment. While automation can facilitate safe handling of higher traffic

levels, a high degree of automation changes the role

of the air traffic controller and may in itself introduce new hazards.

Installation of the Host computer at ARTCCs (see

figure 7-2), the first major step in FAA’s plan to

modernize ATC, is the most significant technology

measure taken in recent years to ease capacity problems. The old system would occasionally overload

and fail, increasing the risk that other events or human errors could snowball into an accident. The

Host computer has much more capacity and speed

then the old system, and includes backup by an

identical computer system in case of failure.

FAA plans to further modernize ATC equipment

and software in a series of steps. According to current plans, the contractor (either Hughes or IBM)

for the modernization will be chosen in July 1988.

The next major step in the process will be-to replace

controller consoles with the Interim Sector Suite

System. Then, hardware for the Terminal Advanced

Automation System will be installed and software

for approach/departure control introduced. Next

comes computer hardware and software for en route

ATC, called the Area Control Computer Complex.

Finally, en route software called Advanced En Route

Automation (AERA) will be introduced. The name

for the whole system of modernized ATC hardware

and software is the Advanced Automation System

(AAS). FAA’s acquisition strategy for AAS has

been criticized by GAO for being too risky; it does

not conform with the principles fundamental to Office of Management and Budget Circular A-109 on

major systems acquisition.22 FAA intends to test

: ] U.S. Department of Transportation, Federal Aviation Adminlstratlon, Narional Airspace S}rstem Plan (Washington, DC: April 1987),

PP. III-9, 111-9, 111-52, and III-53.

‘~U.S. Congress, General Accounting Office, Air Trafi”c Conrrol:

FAA Adtranced Automation System Acquisition Strategy is Risky,

GAO/IMTEC-86-24 (Washington, DC: July 1986).
142

Figure 7-2.— Locations of Air Route Traffic Control Centers

SOURCE: Federal Aviation

HI

Administration,

the system in partnership with a single prime contractor to take advantage of FAA’s ATC and operational experience.

An issue more basic than strict compliance with

Circular A-109, however, is whether the process

fosters innovative approaches to satisfy real ATC

needs in an appropriate time. Emphasis on analytical tools for identifying ATC system needs and on

early prototyping and streamlined procurement

processes could facilitate timely fielding of new technology 23 and evaluation of alternate approaches

to help ensure adequate solutions to ATC problems.

According to current plans, AERA will be implemented in three stages: the first, called AERA-1,

‘]The President’s Blue Ribbon Commission on Defense Management, A Quest for Excellence: Final Reporr to the President (Washington, DC: U.S. Government Printing Office, June 1986), pp. 55-57.

will predict the future positions of aircraft using flight

plan information and alert controllers when potential conflicts occur between planned flight paths up

to approximately 20 minutes into the future. Pilots

may also be able to change flight plans en route,

and a computer would automatically test the flight

plan for potential conflicts with other flights. AERA2 will provide controllers with several alternate resolutions to potential conflicts and will improve coordination between controllers. AERA-3 is not fully

defined, but the basic plan is to have the computer

select the proper resolution of conflicts and communicate course and altitude changes directly to

aircraft.

FAA’s original cost-benefit justification for AAS

included benefits from more controller productivity,

and fuel and passenger time savings from more efficient routes. However, GAO criticized that original analysis severely. Currently, FAA justification
143

is that traffic levels will increase in the future sufficiently that controllers for en route control sectors

will not be able to handle it, and ATC must be automated or more flight delays will occur. Preliminary

FAA estimates suggest that flight delays will be substantial after about year 2000. However, the model

used to estimate the magnitude of delays assumes

the distribution of traffic by time of day is the same

as today, This distribution is likely to change significantl y because of airport capacity limitations and

the changing proportion of nonbusiness travelers.

Much more work is needed to identify ATC needs

for the future and to evaluate potential approaches

to meet the needs.

TRACON Improvements

Current ATC equipment is limited in a number

of ways. FAA’s original plan was to consolidate

ARTCCs and TRACON facilities to form Area

Control Facilities, but that concept is being reevaluated. Objections to the consolidation are partly

operational and partly due to increased vulnerability of the entire system to military destruction.

TRACON facilities, in particular, will be affected

by a rule (required by recent legislation) mandating altitude-encoding transponders for all aircraft

flying above 6,000 feet and in terminal areas where

radar service are required.24 Locations of these terminal areas are shown in figure 7-3. Relief by AAS

is not expected until around the year 2000. The New

York TRACON already has overloaded computer

equipment, because it is served by more airport surveillance radars than its equipment (called ARTSIIIA) was designed for. Efforts are under way to upgrade its capabilities in three phases ending in 1990.

However, within a few years, other ARTS-111A

TRACONs, whose locations are shown in figure 7-4,

will also have increased transponder traffic levels,

and their performance could suffer if their capacity

is not upgraded. Processing capability at ARTS-111A

TRACONs is modular–in the form of up to eight

input/output processors (IOPs), although no TRACON except New York has more than four. Each

IOP costs about $200,000, and if each of the approximately 60 ARTS-111A TRACONs is upgraded by

adding four IOP units, the total cost would be

around $50 million plus costs for overhead and installation. Despite the fact that IOP units are 15-

year-old technology, production lines could be reopened to permit their re-manufacture to provide

near-term capacity increases.

Another improvement for TRACONs would be

installation of a Mode C Intruder Alert function,

which could warn controllers of potential conflicts

between IFR and VFR traffic. The current conflict

alert installed in ARTS-111A equipment alerts controllers only of IFR/IFR conflicts, However, Mode

C Intruder Alert will produce additional false alarms

for the controller, possibly limiting its utility. ARTSIIIA sites would require additional IOP capacity to

handle the Mode C Intruder Alert function in

crowded terminal areas, although additional hardware would not be required in less crowded areas.

Funding to increase TRACON computer capacity

is included in FAA’s fiscal year 1989 budget request,

and Mode C Intruder Alert for ARTS-111A TRACONS is expected to be included in the 1988 version of the NAS Plan.25

“LI. S. Department of Transportation, Federal A\iation Admlnlstratlon, “Transponcler N’ith Automatic Altltude Reporting CapahllIt}’ Requirement and Controlled Airspace Common Floor, ” Notice of

Proposed Rulemaklng, n.d.
144
145

Figure 7-4.—Locations of TRACONS With ARTS-IIIA and ARTS-IIIE Equipment

HI

■ TRACONS currently operating ARTS-HA equipment,

A TRACONS where ARTS-MIA aquipment is not yet operational.

● TRACONs where ARTS-E eq@nent is planned.

KEY: TRACONS = Terminal Radar Approach Control facility.

SOURCE: Federal Aviation Administration,

Beyond expanding the capacity of TRACONs

and installing Mode C Intruder Alert, terminal facilities could be automated to reduce mundane tasks

for controllers. Research has been carried out in the

United States and Germany on terminal automation and improved controller displays, and FAA’s

fiscal year 1989 budget request includes increases in

funding for terminal automation,26

ARTCCs are limited by the number of radar consoles and radars that can be run off the Host computer, limiting expansion possibilities as traffic levels

‘cIbid

increase. Furthermore, equipment in en route centers is old and is becoming more difficult to replace,

and improvements in the basic infrastructure of en

route ATC centers are needed. While the general

principle of reducing controller workload is sound,

other aspects of the cost-benefit analysis for AERA

are more questionable. Controllers will be more dependent on automation support if AERA is implemented, and while FAA plans a lengthy period of

operational evaluation and functional backup for

automated aids, the safety hazards of the changes

in the controller’s role have not been thoroughly

evaluated. Currently, the impact of conflict alerts

which extend 20 minutes or more into the future
146

are not well understood either from a system safety from automation of controller functions could clarify

or an efficiency standpoint. Further examination of whether AERA would permit safe control of higher

the potential hazards and efficiency gains resulting traffic levels.

TRAINING AIR TRAFFIC CONTROLLERS

Air traffic controller training is an immediate concern because many ARTCCs and airport towers

have a shortage of adequately trained personnel.

Some en route facilities report that the current number of personnel is adequate to staff the center, but

that many of their controllers need further training to enable them to operate more positions. Training to full performance level at an ARTCC generally requires over 3 years, although sufficient training

to operate two positions (at which point the controller is called an operational controller) takes less

time.27 Even if present training needs are met, it is

likely that a large number of new controllers will

need to be trained in the near future, because many

current controllers are approaching retirement age.

Prospective air traffic controllers, called “developmental, ” are screened and receive the initial portion of their training at the FAA Academy in Oklahoma City, Oklahoma; then they are sent to an

ARTCC or tower for the next stages of training.

Only about 60 percent of the developmentals who

attend the initial training session at Oklahoma City

pass the screening process, which requires them to

separate aircraft without radar. A 3-week course at

Oklahoma City follows the initial training session

for developmental being trained for towers. This

course includes training in a scale mock-up of a

tower, with small models of aircraft moved around

by hand outside the mock-up to simulate airport

traffic. Developmentals training for ARTCCs undergo radar training with simulations created

through the hardware and software of a system

called Dynamic Simulation (DYSIM). DYSIM ties

into the operational computer of the ARTCC, presenting the trainee with simulated traffic of limited

realism. TRACONs and airport towers with radar

have a radar simulator training system similar to

‘;Peahl, op. cit., footnote 13; Ron Wiest, assistant manager for

Training, Chicago ARTCC, Federal Aviation Administration, personal

communication, Sept. 10, 1987; Richard Dilley, assistant manager for

Training, Los Angeles ARTCC, Federal Aviation Administration, personal communication, Sept. 11, 1987.

DYSIM called Enhanced Target Generator.28 Beyond simulator and classroom training, ARTCCs,

TRACONs, and towers rely heavily on on-the-job

training for developmentals.

The Seattle ARTCC uses an upgrade of DYSIM,

called Computer Enhanced Radar Training (CERT),

which has improved software that more realistically

simulates sector traffic. The CERT program emphasizes good use of instructors and the proficiency of

operators who simulate pilots. As a result of these

improvements, the Seattle ARTCC has cut by over

50 percent the time needed at certain stages of con--

troller training, and has reduced time spent for onthe-job training with live traffic by 18 percent.29

The realism of training is limited, because software does not allow simulated traffic to deviate from

preferential arrival and departure routes in the live

“Ann Spence, air traffic subject matter expert, Federal A\,iatlon

Administration, personal communication, Aug. 27, 1987.

2“U.S. Department of Transportation, Federal A\”iation Administration, “Seattle Center Computer Enhanced Radar Training Staff

Study,” unpublished manuscript, n.d.

Photo credit: Federal Aviation Administration

Air traffic controller trainees receive instruction at the

Seattle Air Route Traffic Control Center’s Computer

Enhanced Radar Training (CERT) laboratory.
147

system, 30 and the call signs of simulated traffic

must begin with XXX, a pattern never encountered

with real traffic. Moreover, some ARTCCs lack

sufficient equipment to train all their developmental simultaneously, so developmental spend more

time at intermediate levels than may actually be necessary.’ ] In other ARTCCs, on-the-job training of

developmental is an additional and taxing task for

full performance level controllers.’: To deal with

these problems, a few ARTCCs have begun sending controllers back to Oklahoma City for sitespecific radar training at the Academy.33 At Oklahoma City, developmental receive increased personal attention and specific remediation, perhaps

‘CA.T. Snelson, alr rrafflc manager, Seattle ARTCC, Federal Aviation Admlnlstratlon, personal commumcatmn, Aug. 18, 198?.

“Peahl, op. cit., footnote 13.

‘

: Dilley, op. cit., footnote 27.

“Dennis Burke, manager, Chicago ARTCC, Federal Aviation

Admln]stratlon, personal communication, Sept. IO, 198?.

more important than the Academy’s more versatile radar simulation capabilities.34

These alternatives point to possibilities for nearterm improvements to training capabilities at

ARTCCs. For the longer term, airline pilot training could be used as a model, with microcomputers

for basic subsystem training and realistic simulators

for full operations. Combined with appropriate

levels of individual attention, simulator training

could reduce or even eliminate the need for on-thejob training of developmental and reduce the time

needed to reach operational and full performance

levels. FAA is now taking a first step by revising

its Instructional Program Guide for en route training to increase site-specific simulator training at each

ARTCC.

35

~4B. Keith Potts, Federal Aviation Administration, attachment to

letter to OTA, Feb. 22, 1988.

“Ibid.

COLLISION AVOIDANCE TECHNOLOGY

Traffic Alert/Collision Avoidance Systems (TCAS)

provide independent backup to the ATC system

and help pilots fulfill their responsibility to see and

avoid other aircraft. Three types of TCAS capability are being developed: TCAS-I, TCAS-II, and

TCAS-III. TCAS-I, the least sophisticated of the systems, warns of nearby traffic by giving traffic advisories that indicate the approximate bearing of each

threat and the approximate altitude, if the threat

aircraft is equipped with an altitude-encoding transponder. TCAS-I is intended for GA use and for

small commercial aircraft. TCAS-II and 111 also supply resolution advisories to help the pilot maneuver

away from an impending collision or close approach.

TCAS-II can advise only vertical maneuvers, while

TCAS-III can advise both horizontal and vertical

maneuvers. TCAS-II and III are intended for use

on large jet aircraft and turbine-powered commuter

aircraft.

All three systems require the threat aircraft to

have an operating transponder to function in the

traffic advisory mode; resolution advisories are generated by TCAS-II and 111 only if the threat aircraft

has an operating altitude-encoding transponder. The

Mode S data link communications system, now being developed by FAA, will be used for air-to-air

interrogation/reply with TCAS-II and III to coordinate maneuvers when two TCAS-equipped aircraft

must evade each other.36

TCAS-II, the most advanced in development of

the three systems, is currently undergoing flight testing scheduled for completion by the end of 1988.

TCAS-III has had initial flight tests, but technical

challenges remain in collision avoidance logic, human factors, interaction with ATC, certification

standards, verification tests, and performance monitoring. TCAS-I development is not as far along as

either II or III.37

Current TCAS issues include the adequacy of vertical-only maneuvers for collision avoidance, as supplied by TCAS-II. TCAS-III would provide horizontal and vertical maneuvers, but will not be available

soon; moreover, it is projected to cost about $20,000

to $30,000 more per copy than TCAS-II. 38 F AA

36~2 F~d~ral Register 32269 (Aug. 26* 1987~”

‘

-

Joseph Fee, TCAS program manager, Federal Aviation Administration and Dan Tillotson, senior project leader, ARINC Research,

Inc., presentation at Air Line Pilots Association 1987 Safety Forum,

Aug. 19, 1987.

‘

e

Ibid.
148

Photo credit: Federal Aviation Administration

FAA pilots flight-test a collision avoidance system.

has issued a Notice of Proposed Rulemaking requiring TCAS-II in all Part 121 aircraft and larger Part

135 aircraft with turbine engines, and encouraging

manufacturers to build TCAS-II units that can be

upgraded to TCAS-III without major changes in

hardware. The Airport and Airways Safety and

Capacity Expansion Act of 1988 requires development of TCAS-II with standards upgradable to

TCAS-III. 39

GA aircraft operating without transponders will

remain problems, since TCAS warns only of aircraft with operating transponders and provides a

resolution advisory only if the threat aircraft has

an altitude-encoding transponder. FAA rulemaking to require Mode C (i.e., altitude-encoding) transponders on aircraft flying above 6,000 feet and in

terminal airspace where radar coverage is provided

will induce GA pilots to buy altitude-encoding transponders. Currently, Mode C transponders are required only above 12,500 feet and in Terminal Control Areas. This FAA rulemaking was mandated by

Congress as part of a program to reduce the potential for midair collisions. Even with the increased

Mode C requirements, a small plane operating without a Mode C transponder could still inadvertently

enter terminal airspace with radar coverage. A program to gradually require transponders in all aircraft would provide additional safeguards.

Technical uncertainties still surround TCAS, because the reactions of controllers and air traffic patterns to TCAS-induced altitude changes are relatively untested. The major potential ATC problem

is a threat to a third aircraft if an aircraft suddenly

changes direction or altitude. Simulations suggest

such a problem is extremely unlikely. Because of the

complexit y of retrofitting TCAS to existing aircraft,

it will be gradually introduced, easing potential ATC

adjustments.

Ground Collision Avoidance

Although the United States has had few fatalities from collisions on the surface at airports, a number of nonfatal collisions and close calls have

occurred. As traffic levels increase the probability

of a disastrous ground collision will increase unless

compensatory steps are taken. Twelve major airports

have Airport Surface Detection Equipment (ASDE2) radar to present surface traffic information to controllers (see figure 7-5). This equipment is about 25

years old, expensive to maintain, and has performance limitations. Anchorage, Alaska, has a more

advanced surface detection radar. FAA plans to replace ASDE-2 with the more advanced ASDE-3 and

to field ASDE-3 at some additional airports. ASDE3 radar can be enhanced by automatic conflict alert

and further automated through digital air/ground

communications links.

Other fairly simple means to improve ground collision safety include improved signs on the airport

surface, control lights at entrances to active runways,

and training pilots and controllers to exercise greater

vigilance during taxi operations. First, a short-term

research and development (R&D) effort to improve

sign symbology could provide input for developing

consistent standards for taxiway and runway signs

at all U.S. airports. Second, radio-controlled light-
149

TCAS

CLIMB. CLIMB

TCAS

TCAS

Photo credit. National Aeronauts and Space Administration

Traffic Alert/Collision Avoidance System (TCAS) will provide both visual and aural alerts to the pilot.

ing systems could be installed at entrances to major runways to augment runway clearances from

ground controllers. More air traffic controllers for

tower operations would be needed to operate the

lights. A system of in-pavement stop-bar lights and

above-ground signal lights will be tested on 14 runway entrances at JFK Airport (approximately onequarter of the airport entrances) during 1988. The

cost of equipment and installation for the lighting

will be about $600,000, but a similar installation at

most other major airports would be much more expensive, because, unlike most airports, JFK already

has a static bar light system at entrances to runways.

Third, training for pilots and controllers on preventing runway incursions could be increased.

For the longer term, work now underway at the

FAA Technical Center on sign readability under

very low visibility conditions deserves continued support. Also, more advanced sensors for detecting traffic on the airport surface could be developed, along

with improved displays for controllers and development of procedures that permit monitoring of the

displays as part of a reasonable workload.
150

Figure 7-5.-Locations of Airport Surface Detection Equipment Radars

HI

NOTE: The ASDE in Anchorage, Alaska is more sophisticated than the systems at the other locations

SOURCE: Federal Aviation Administration.

COMMUNICATIONS

Ground-to-air communications systems are used

to transmit ATC, weather, maintenance, and airline administrative information. Existing communications systems include many types: voice and data

systems, one-way and two-way systems, and both

government and private-owned systems. Analyses

have shown that communication problems are significant sources of system safety vulnerability. For

example, FAA reports that controller communication with pilots and other controllers was the second most frequent cause of operational errors at

ARTCCs and third at TRACONS.

40 

— The process

wu s Department of Transportation, Federal Aviation Adminis- . ,

tration, Office of Aviation Safety, Profile of Operational Errors in the

National Airspace System, Calendar Year 1986 (Washington, DC: November 1987), p. 4-55.

of communication between ATC and the aircraft

crew is also a significant problem according to

the National Aeronautics and Space Administration’s (NASA) Aviation Safety Reporting System

database. 41

The very-high frequency (VHF) voice system linking pilots to FAA ground facilities is a government

system primarily used to transmit ATC and weather

information, and for flight plan processing. The

voice link between pilots and ATC facilities is also

the final backup in case all computers or radars fail.

+( David c. Nage], Chief, Aerospace Human Factors Research Division, National Aeronautics and Space Administration, letter to OTA,

Jan. 26, 1988.
151

An air traffic controller can operate with multiple

frequencies, and may have as many as 30 pilots on

one frequency. When many pilots are on the same

frequency, each must wait for a gap in communications with the other pilots before transmitting a message, slowing communications in busy airspace.

While air traffic controllers are required to issue

windshear advisories, they provide weather forecast

information only as their higher priority functions

of separating aircraft and issuing safety alerts allow.

Nineteen percent of controllers responding to a 1985

GAO survey reported they often declined to provide weather information to pilots when working

peak traffic periods. Another 34 percent said they

occasionally decline to give weather advisories.42

Air/ground communications is the weakest link in

transmission of weather information from sensors,

observers, or meteorologists to pilots in flight.

One advantage of having many pilots on the same

frequency is that all the pilots on the frequency can

hear the messages transmitted and received by other

pilots. For example, pilots may transmit pilot reports

about weather or runway conditions over the VHF

voice link. Other messages that are important to pilots on the “party line” include altitude assignments,

ATC clearances, and communication frequency

changes.

Radio-frequency failures are less common now

than in the past for the ground-based VHF voice

link, because most of the aging equipment in the

field has been replaced by modern, solid-state equipment, including standby equipment in case the primary equipment fails. Nowadays, when a failure occurs, it is more likely to be caused by problems with

the leased telephone lines that connect ATC facilities to transmitters and receivers in the field. The

national reliability for en route ground-to-air communications, including both FAA equipment and

interconnecting links for fiscal year 1987 was 99.6

percent, up from 99.1 in fiscal year 1978.43 Because

a frequency can be blocked if a microphone is stuck

in the transmit position, the Radio Technical Commission of America is currently developing standards for devices to alert pilots when this problem

occurs. When completed, the standards could be

used as a basis for an FAA regulation requiring

stuck-microphone alerters in aircraft. Short-term

R&D to determine and validate improved ways to

utilize analog voice links could enhance current

methods.

The government also operates broadcast voice

links for transmission of weather and other information to pilots. Services include the Hazardous InFlight Weather Advisory Service, which is broadcast from selected navigation stations, and the Automated Terminal Information Service (ATIS). ATIS,

which is broadcast from navigation stations located

on or near airports, is a continuous broadcast of

recorded non-ATC information. ATIS relieves airport tower controllers from having to provide certain environmental and runway use information to

individual pilots.

VHF radio has limited range, so it cannot be used

for transoceanic flight. Instead, high-frequency (HF)

radio is used. However, HF communication is not

very reliable and long delays sometimes occur before messages can be received. Over land, the secondary surveillance radar system, described later in

more detail, communicates altitude data and a code

number assigned by ATC for each aircraft from air

to ground.

Aeronautical Radio, Inc. (ARINC), a cooperative

owned by over 50 airlines and aviation-related companies, owns and manages the ARINC Communications Addressing and Reporting System (ACARS),

a terrestrial digital data link for use by airlines.

Nearly 75 percent of the commercial fleet is equipped

with ACARS, which provides continuous coverage

above 20,000 feet in the United States and onground coverage at 95 principal airports.44 ACARS

is used primarily for aircraft operational control and

administrative communications, as well as for automatic aircraft reporting, such as allowing an aircraft

with a system/servicing problem to alert maintenance to have appropriate resources waiting at the

airport for its arrival. Weather information prepared

by airlines is also transmitted over ACARS, most

of it in textual format,45 although Northwest Air-

‘~U.S. Congress, General Accounting Office, Aviation Weather:

Status of FAA New Hazardous Weather Detection and Dissemination Sysrem, GAO/RCED-87-208 (Washington, DC: September 1987). ~)wayne ]. Bar]ow, director, Northwest Mountain Region, Federal

Aviation Administration, letter to OTA, Dec. 22, 1987.

44R A Pickens, vice president, Engineering, Aeronautical Radio,

Inc., ~et~er to OTA, July 30, 1987.

+5Rick Hambly, chief of ACARS section, Aeronautical Radio, Inc.,

personal communication, Aug. 24, 1987.
152

lines transmits graphical weather information to pilots of its Boeing 757 aircraft over ACARS.46

ACARS is nearing capacity in the northeastern

part of the United States, so ARINC has been developing an upgrade. Enhanced ACARS (EACARS)

will use up to six separate frequency channels, instead of the single channel of the current system,

and will be capable of transmitting at a higher bit

rate than ACARS. In addition, the data will be encoded in a format more compatible with transmission of graphical information.47

Other privately-owned communication systems

used by commercial aviation include the company

radio systems of airlines. Northwest Airlines has an

eight-frequency analog radio system, over which it

transmits graphical weather information to pilots,

using audio tones.48

Two fundamentally new types of communications

systems are currently being developed for aviation

use: the government’s Mode S data link and industry’s satellite communications systems. The expected

proliferation of digital communications links raises

the possibility of coordinated development to provide air/ground communication that is more reliable and has better coverage and capacity than any

of the individual links.

The Mode S data link, part of the NAS Plan, is

a subsystem of the Mode S secondary surveillance

radar system. Mode S interrogations can be addressed to individual aircraft, and the signal format

allows bursts of data to be transmitted from the

ground on interrogations and from aircraft on replies. Thus, if an aircraft is equipped with a Mode

S data link transponder, two-way air/ground communication is possible.

Future plans include integrating Mode S data link

with the Advanced Automation System to provide

digital communications between controllers and pilots, as well as weather information through other

interfaces. For the near term, however, a relatively

limited set of functions is planned, including fairly

simple weather messages, pilot advisories, and confirmation of assigned altitudes and communication

frequencies. 49

Mode S implementation is expected to proceed

in two phases, with installation of Mode S secondary radars on the ground sufficient to provide nominal coverage down to 12,500 feet above mean sea

level in the United States and down to the surface

of major airports by 1992 as the first phase. Phase

two will involve installation of more Mode S secondary radars on the ground to provide coverage

down to 6,000 feet in the United States by 1994.

Mode S data link is robust because of its decentralization and because adjacent ground radars often

have overlapping coverage. However, it is basically

a line-of-sight system, likely to have coverage gaps

near the surface of airports and in mountainous regions, although some additional coverage could be

provided by installing extra omnidirectional antennas at airports. Moreover, Mode S will not provide oceanic coverage and is inefficient for broadcast communications, because messages can be

received only by aircraft within the main antenna

beam of the interrogator (with, perhaps, some exceptions). In addition, information currently available to pilots over the VHF voice party line will be

lost with Mode S data link and other discreetly addressed communications systems, unless special provisions are made to transmit that information.

INMARSAT, an international consortium that

operates a global satellite system for mobile communications, is working with three groups, including ARINC, to develop aviation satellite services,

mainly for oceanic travel.5o If disputes over frequency allocation can be resolved, the services could

be used by U.S. airlines for oceanic ATC, aircraft

operational control, and administrative communications, as well as for passenger phone calls in flight,

an economically attractive use. Satellite communications systems are relatively expensive to use. Moreover, if all types of aeronautical communications are

in the same frequency band, a system must include

a feature to override passenger or administrative

communications should a safety-critical message

‘John Dietrich, Meteorology Department, Northwest Airlines, personal communication, Aug. 24, 1987.

47 Hambly, Op. Cit., footnote 45”

48Dietrich, op. cit., footnote 46.

4~oseph Fee, Federal Aviation Administration, personal communication, Sept. 15, 1987.

~im Clark, Aeronautical Department, Service Development Office,

INMARSAT, personal communication, Jan. 6, 1988.
153

need to be sent. However, a satellite system would

provide reliable coverage to the ground over a wide

area on the Earth’s surface, including oceans, and

would be less subject to coverage gaps due to obstructions and multipath effects than terrestrial

systems.

The complementary strengths and limitations of

Mode S data link, satellite communications systems,

and ACARS, point to the value of an integrated

approach to aviation communications. Presently,

FAA is developing compatibility standards for groundto-air digital communications systems, using the

Open System Interconnection (OSI) model developed by the International Standards Organization.

The OSI model, which has been applied in the past

to ground-to-ground communications systems, defines communications systems in terms of universal levels which may be common to more than one

system. Ideally, if digital communications systems

are standardized and integrated, aircraft will not

need dedicated hardware for each system. More importantly from a safety standpoint, a pilot could send

a message without specifying a particular communications system, and the integrated system would

choose the system based on coverage, capacity, and

other considerations. Thus, the integrated system

would have more coverage and greater reliability

than any individual communications system. Although FAA is developing Mode S standards based

on the OSI model, and EACARS and the ARINC

satellite system are similarly based,51 FAA and industry have not yet decided to actually attempt to

integrate the communications systems. The integrated

system concept for air/ground communications systems has attracted the interest of both government

and industry representatives on International Civil

Aviation Organization committees. 52

Although digital communications links hold great

promise for the future, they will not replace the current air/ground analog voice communications links

as the primary system for real-time ATC and

weather information until at least well into the

1990s. A great deal of work is still needed to estab-

‘*Rick HambIy, chief of ACARS section, Aeronautical Radio, Inc.,

personal communication, Sept. 18, 1987; Walter J. Gribbin, Aeronautical Radio, Inc., “AvSat, An Aeronautical Satellite Communications

System,” unpublished manuscript, n.d.

5~Earnest Lucier, Federal Aviation Administration, personal communication, Sept. 16, 1987.

lish and validate a workable set of services for the

digital links, and to implement an integrated system into commercial aircraft cockpits and into

ground systems. issues of what information to transfer over data links, when to transfer it, and to whom,

have not been resolved.

Navigation

Navigation systems help the pilot determine position with respect to points on the ground. instruments on board aircraft use signals from navigation

aids or from inertial navigation/reference systems

on board to show aircraft position on a display such

as a horizontal situation indicator. inertial navigation systems may include special-purpose computers

that provide precise Earth latitude and longitude,

ground speed, course, and heading. integration of

navigation systems with automatic pilot allows automatically controlled flight and landings under low

visibility conditions. Using the most advanced integrated navigation/automatic pilot systems now

available, a pilot could, in principle, fly an airplane

automatically from takeoff to landing, except for

control of the landing gear, flaps, and engine

reversers.

The NAS Plan includes implementation of MLS

to replace the current ILS. MLS has several technical advantages over ILS, because it is not susceptible to unintentional signal reflections from structures or terrain on or near the airport, and it

operates at a frequency band that can accommodate more locations than ILS. MLS can provide

signal-in-space accuracy exceeding the requirements

of Category III ILS (the most stringent requirements). However, initial MLS units will operate only

at Category I, whereas some ILS sites now operate

to Category III. MLS can be implemented on runways near water or in mountainous terrain where

ILS cannot be used effectively, and is operationally

compatible with heliports and future tilt-rotor landing areas, which ILS is not. Finally, MLS allows

curved and segmented approaches to runways, although curved and segmented approaches at many

airports will be restricted by operational and noise

constraints. MLS may increase the capacity of some

airports and reduce the communications load on

air traffic controllers. However, control of a mixed

population of MLS and ILS traffic will be difficult,

so most aircraft flying into an airport would need
154

to be equipped with MLS avionics to realize the

maximum capacity gain.53

The Loran-C navigation system, which gives bearing relative to radio beacon transmitters, has become

more popular as a low-cost navigation system with

many pilots, and its coverage is being expanded to

include the Midwestern United States. However,

Loran-C does not offer redundant coverage in all

areas; the loss of a single transmitter means that

many aircraft over a wide area lose Loran-C navigation capability. By 1991, however, a satellite-based

navigation system, the Global Positioning System,

deployed by the Department of Defense, should be

operational, and could be used in conjunction with

Loran-C to provide redundant coverage. Such redundant coverage could encourage development of

new surveillance concepts based on automatic position reports from aircraft in areas not covered

adequately by surveillance radars. 54 Automatic position reports would allow much more accurate surveillance of en route oceanic traffic, enhancing air

traffic system capacity over oceans.

Surveillance

Two types of surveillance radars detect the positions of aircraft for presentation to air traffic controllers. Primary radar sends out a beam of radiofrequenc y pulses and measures the distance to aircraft targets by the time it takes to receive the return pulses reflected from the metal surfaces of the

aircraft. Secondary radar sends out pulse-coded interrogations on a radio-frequency beam, which are

received by transponders on board aircraft. The

transponders reply to each interrogation with a

coded response. The replies can be encoded with

altitude or identification information. This system

of ground interrogators and airborne transponders

is known as the Air Traffic Control Radar Beacon

System (ATCRBS).

Both primary and secondary surveillance radar

systems will be upgraded under the NAS Plan.

Aging radars at 96 major airports will be replaced

‘

]National Aeronautics and Space Administration and Stafford, op.

cit., footnote 10; Joseph M. DelBalzo, director, Eastern Region, Federal Aviation Administration, “MLS Today for More Capacity and

Less Noise Tomorrow,” presentation at Royal Aeronautical Society,

London, February 1988,

‘

+ Federal Aviation Administration, op. cit., footnote 20, pp. 6-16

through 6-18.

by the ASR-9 radar, which offers improved target

and weather detection capabilities that do not exist in the current airport radars. The more modern

airport surveillance radars (ASR-7s and ASR-8s) already at airports will be transferred from airports

receiving ASR-9s to smaller airports. Many en route

surveillance radars along the boundaries of the

United States will be replaced by the ARSR-4, which

is being developed by FAA and the Air Force. The

current ATCRBS secondary surveillance radar system will be replaced by Mode S, which also functions as a communications system. Overall, these

upgrades in surveillance capabilities will improve the

accuracy of surveillance and increase the reliability

of the system, as well as provide better weather and

ATC information to pilots.

Photo credit: Westlnghouse Electric Co.

The first production system of the ASR-9 Airport

Surveillance Radar undergoing test at BaltimoreWashington Airport
155

WEATHER TECHNOLOGIES AND TRAINING

The types of weather of most concern to commercial aviation pilots are: current and forecast surface

conditions, convective weather and associated precipitation and turbulence, clear air turbulence, icing, winds aloft (although this is rarely a safety factor), and windshear near the surface. Windshear

near the surface is particularly significant because,

over the past 10 years, windshear contributed to

almost one-half of all fatalities resulting from commercial aircraft accidents during takeoff and landing.

Weather technologies include weather sensors,

technologies for data interpretation, message formulation and display, and communications technologies. Other technologies deal with the effects of

weather, such as de-icing technologies (which are

discussed in chapter 8). Some weather technologies

are entirely contained within the aircraft, and others

are ground-based, with perhaps a ground-to-air communication link to relay the information to the pilot. Many technologies that address weather also

have other functions.

Several generic types of weather sensors are commercially available for use on the aircraft, including weather radar, sferics (atmospherics) detectors,

and windshear warning systems. Weather radar presents to the pilot radio-frequency reflectivity levels,

which suggest precipitation rate, on a map display.

Since turbulence is typically a greater hazard to aircraft than precipitation, methods have evolved for

using reflectivity data to infer the probable existence

of turbulence, Some newer models of airborne

weather radar include a Doppler channel for direct

detection of turbulence. From the standpoints of

engineering approach and use in the cockpit, Doppler radar remains a developing technology.

Neither conventional nor Doppler airborne radar is capable of reliably detecting clear air turbulence, which may appear separate from storms or

in the vicinity of storms. Also, airborne weather radars may be attenuated by nearby precipitation or

by ice on the radome, although some newer models

have a feature that warns pilots when signals are

being attenuated. For these and other reasons,

proper use of airborne weather radar is by no means

straightforward and requires training and experience

on the part of the pilot.

Sferics detectors passively detect electrostatic discharges in the atmosphere. The presence of discharges suggests convective activity where turbulence may be present. Sferics detectors derive the

range of detected weather statistically from the

strength of received signals. As such, the range of

detected weather may be significantly in error. The

output displays of both weather radar and sferics

detectors may be integrated with the horizontal situation indicator in cockpits equipped with CRT displays, so that the pilot sees weather in relation to

navigational aids, waypoints, and intended route

of flight on a display.

Federal regulations require weather radar for Part

121 operators55 and for Part 135 operators when

operating large, transport category aircraft.56 Smaller

aircraft with at least 10 passenger seats must carry

approved thunderstorm detection equipment; 57

these aircraft may carry an approved sferics detector instead of weather radar.

Windshear

Windshear warning systems use the performance

of the aircraft itself as a sensor of conditions that

indicate the presence of a potentially dangerous

windshear. Of all the possible types of windshear,

the microburst is usually the most dangerous, and

windshear warning systems are optimized to detect

the microburst. Visual and audible alarms sound

when performance of the aircraft suggests the presence of a windshear. Newer models of windshear

warning systems can provide guidance to assist the

pilot to escape the windshear, and the warning system can be coupled to the aircraft’s autopilot to

automatically execute procedures to escape the

shear. The weakness of current windshear warning

systems is that the aircraft must already have entered the windshear to detect it; this may be too

late to escape the most severe shears. Detecting

windshear conditions prior to entry represents a significant technological and economic challenge to the

aviation industry.

5514 CFR 1.21.357 (Jan. 1, 1987).

5614 CFR 135.175 Uan. 1! 1987).

5714 CFR 135.173 (Jan. 1, 1987).
Windshear warning systems are not currently required in aircraft; however, a recent Notice of Proposed Rulemaking would require windshear warning with flight guidance for Part 121 aircraft, along

with training for pilots, and training in windshear

avoidance and escape for pilots of Part 135 operations. 58 Many airlines include simulator windshear

training to alert flight crews to the indications of

incipient windshear and to help them in controlling the aircraft so as to retain sufficient power during escape/avoidance maneuvering.

Because of the many subtleties in the use of cockpit weather sensors, and because of their inherent

5852 Fe&raj Register 20559-20571 @ne 1, 1987).

limitations, adequate, appropriate training is essential for their proper use. The training must involve

instruction in the actual use of the equipment, as

well as recognition of visual cues for dangerous

weather conditions, such as windshear. FAA sponsored joint industry/government development of a

windshear training program, called Windshear

Training Aid. Completed in February 1987, the program represents the consensus of airlines, manufacturers, pilots, the research community, and government regulatory and safety agencies. The training

program is part of the Integrated FAA Wind Shear

Program Plan.59

5“E.A. Kupcis, “Windshear Training Aid,” Boeing Airliner, JulySeptember 1987, pp. 2-7.
157

Although windshear training is receiving increased

attention at this time, training programs for use of

weather information in the cockpit are believed by

some experts to be inadequate. m 1n particular,

many airlines provide minimal pilot training in the

use of information such as that available from airborne weather radar. The situation has become

more acute as airlines have cut staff and are less

equipped to offer professional meteorological help.

National Weather Service

FAA, the National Weather Service (NWS), and

some commercial organizations are involved with

detecting weather, interpreting the information, and

communicating the information to pilots and FAA

field personnel. The NWS Aviation Services Branch

is in charge of providing aviation weather information, and relies on FAA to stipulate the requirements for the information, Airlines, as well as FAA,

use information provided by NWS for functions

such as pilot briefings.

NWS operates ground sensors on airports (FAA

also operates ground sensors on airports; in fact,

more than NWS), 61 Geostationary Operational

Environmental Satellites (GOES), upper-air sounding devices, and Weather Service Radars to sense

weather for aviation and other users. NWS meteorologists interpret information from the sensors to

produce products specifically tailored to aviation

needs, such as Terminal Forecasts.

FAA operates Flight Service Stations (FSSs) to

provide preflight briefings and in-flight weather information over VHF radio primarily to general aviation pilots, although Part 135 operators use FSSs

as well. FSSs are staffed by FAA personnel who are

not meteorologists, but who are specifically trained

and have access to information from NWS sources,

including GOES data, surface observations, and

forecasts produced by NWS meteorologists.

‘John McCarthy, in U.S. Congress, Office of Technology Assessment, “Transcript of Proceedings-OTA Workshop on Technology in

Commercial Aviation Safety,” unpublished typescript, July 1, 1987,

pp. 169-170.

C] Robert E. Brown, deput y director, Program Engineering Service,

Federal Aviation Administration, letter to OTA, n.d.

Air Traffic Control Role

Air traffic controllers in ARTCCs, TRACONs,

and airport towers are an important source of weather information to commercial aviation pilots, although when controllers are busy managing crowded

airspace, significant delays occur before weather information is relayed to pilots. Controllers currently

receive weather information from pilots in the form

of pilot reports, from the weather channel of the

en route surveillance radar (and in the future, from

ASR-9), from the Center Weather Service Unit

(CWSU) meteorologist located in each ARTCC,

from NWS products supplied directly to them, from

direct observation (in the case of tower cab controllers), and from FAA’s Low Level Windshear

Alert System (LLWAS). The communication links

between the sources of weather information and

controllers are often primitive; CWSU meteorologists sometimes leave their CWSU stations to deliver messages by hand to controllers.

Automation and digital air/ground communications could reduce or eliminate the controller’s role

in the process of providing weather information to

pilots. However, controllers themselves need to be

aware of bad weather to anticipate when pilots are

likely to ask for deviations from their initial flight

plans, so they can manage the traffic situation better. Traffic management controllers at ARTCCs

and, nationally, Central Flow Control controllers

need accurate weather information, so they can adjust traffic flows to the capacity of the system.

LLWAS is a system that employs wind vanes and

anemometers in the vicinity of an airport to generate windshear alerts for tower controllers, who are

supposed to broadcast the information to pilots under their control. LLWAS was developed in the

1970s before windshear phenomena were understood very well, and is optimized for detecting gust

fronts, which are relatively harmless to large aircraft,

rather than for detection of deadly microbursts.

LLWAS misses some microbursts because the sensors are too widely spaced, produces many false

alarms, and its alarms are not timely enough to track

the rapid buildup and decay of most microbursts.62

6ZJohn Mccarthy, NationalGnter for Atmospheric Research, “TO

Improve the Detection of Hazardous Aviation Weather,” testimony

before U.S. Congress, House Committee on Public Works and Transportation, Aviation Subcommittee, Oct. 2 and 30, 1985, pp. 23-61.
158

Figure 7-6 plots windshear accidents and incidents

for transport category aircraft by year since 1964;

no statistical evidence shows that LLWAS has reduced the rate of incidence of windshear-caused accidents.

Weather Research and Development

R&D into windshear sensors falls into two categories, ground-based and airborne, and both categories

are being pursued by FAA as part of its integrated

Wind Shear Program Plan. 63 Two ground-based

windshear detection technologies are being developed: an enhanced version of LLWAS and Terminal Doppler Weather Radar (TDWR). Enhanced

LLWAS includes more sensors at each airport and

software changes to allow better and more timely

detection of microbursts. However even enhanced

S]u s DeP~rt~ent of Transportation, Federal Aviation AdrninlS-

. .

tration, Integrated FAA Wind Shear Program Plan (Springfield, VA:

National Technical Information Service, April 1987).

Figure 7-6.—Windshear Accidents and Incidents

Before and After LLWAS Implementation

LLWAS cannot detect microbursts before they hit

the ground, which may be too late. TDWR may permit early detection of microbursts, and could be

more reliable than enhanced LLWAS, although obstructions on or near the airport surface would limit

the coverage of TDWR. One major technological

challenge is to develop and validate computer algorithms for automatic detection of microbursts with

TDWR.

Originally FAA planned to deploy TDWR at

about 100 airports, but the Office of Management

and Budget recently restricted the number to 44,

based on cost-benefit analysis.64 An integrated sensor system consisting of both enhanced LLWAS and

TDWR may be the best choice at airports where

the windshear threat justifies deploying both, but

the problem of integrating the sensors to produce

a single message to pilots and controllers needs to

be solved. Another challenge is to develop a message format and a reliable means of communication

of the information to pilots. A message format developed in 1987 by a users’ working group has been

used at Denver with the enhanced LLWAS, and

has been found satisfactory for the TDWR operational demonstration scheduled for summer 1988.

Development of ground-based windshear detection

technology that is less expensive than TDWR, but

more capable than enhanced LLWAS, would help

alleviate microburst risk at smaller airports with increasing traffic levels.

Airborne windshear sensors are in a more preliminar y stage of development than the ground-based

sensors. FAA is underwriting the basic technical and

scientific developments in airborne systems to the

point where technologies can be developed and marketed commercially. Airborne sensors do not have

the coverage limitations of ground sensors, do not

rely on a ground-to-air communications link, and

provide advance warning. Microwave radar and

light detection and ranging technologies are currently undergoing assessment by FAA and a consortia of manufacturers, and at least two companies

are independently investigating look-ahead infrared

temperature sensors for microburst detection.6s

‘Arthur L. Hansen, manager, Weather Radar Staff, Federal Aviation Administration, personal communication, Mar. 3, 1988.

65Herb Schlickenmaier, project manager, Airborne Windshear Detection and Avoidance, Federal Aviation Administration, personal communication, Nov. 3, 1987.
159

FAA, NWS, and the Department of Defense are

participating in a joint program, called NEXRAD

(next generation weather radar), to upgrade the current system of radars used to map rainfall levels

across the United States. NEXRAD is planned to

replace the current network of NWS radars, and

to provide both reflectivity and velocity dispersion

information for determination of turbulence levels.

NEXRADS will be sited temporarily at airports

where windshear is an especially serious threat to

serve as interim terminal weather radars before

TDWR is introduced. The issue of how to present

NEXRAD information to pilots–through controllers or as a graphical product–has not yet been resolved. Air traffic controllers will receive graphical

NEXRAD information.

Automated systems to collect other weather information in the terminal area are being developed

by both FAA and NWS. The replacement of human observers by these systems is currently controversial, and message formatting and communication of the information to pilots are unresolved

issues. NWS plans to upgrade its capabilities for providing information and making forecasts include

replacing the current data analysis and distribution

system with a sophisticated network of computing,

LIABILITY

Liability issues haunt aviation safety because an

accident that implicates a safety technology or training program could cost a manufacturer or airline

more than it is worthwhile to risk. For example, Boeing nearly backed out of its participation in the

Windshear Training Aid program over liability concerns, until the Secretary of Transportation intervened and convinced the manufacturer to continue.

67 The industry-wide endorsement of the

b;Edgars A. Kupcis, New Product Development, Boeing Commercial Airplane Co., personal communication, Aug. 4, 1987.

communications, and display capabilities. Another

developing technology is the profiler system to replace current balloon technology for upper atmospheric measurements; the results for aviation include

more accurate and timely winds information, hazardous weather warnings, and forecasts for better

airspace planning.

Some airlines have meteorology departments that

handle preflight briefings, and all airlines are required to have dispatch organizations that transmit weather information to pilots over the company

radio system or over ACARS.66 Some pilots utilize

publicly televised weather programs such as “A.M.

Weather,” or newspapers to obtain weather information.

Improving weather information available to pilots

requires better training for NWS forecasters and observers, air traffic controllers, and flight service station specialists in use of weather information and

observing weather. Moreover, as new weather sensor

technologies are fielded, training for users of the information must be stepped up to ensure safe air

travel.

~14 CFR 121.599 and 601 (Jan. 1, 1987)

ISSUES

results of the program suggest that a valuable product for making commercial aviation safer would have

been lost if the project had been abandoned. No

other commercial aviation safety technologies or

programs have been identified which are in danger

of extinction because of liability, but new industry

initiatives in the future could be impeded. Liability

has had a large impact on the GA industry; while

tort actions have produced improvements in areas

such as handbooks and crash survivability, the GA

industry is in severe financial straits.

CONCLUSIONS AND POLICY OPTIONS

While further safety improvements through technology will come at relatively high cost, several technology areas show real promise for improving the

current level of safety even as demands increase on

the air system.

Some ATC facilities are already severely taxed because of inadequate equipment and unmet controller

training needs. Installation of Host computers at en

route centers was a major step in bringing up the

capabilities of the centers to meet traffic demands.
160

However, equipment at en route centers, TRACONS,

and airport tower cabs is old and difficult to replace;

furthermore, the centers have limited expansion capabilities to handle more radars and controller positions. AAS will upgrade capabilities at air traffic

facilities, but the system will not be ready in time

to head off capacity problems before the mid- to

late-1990s.

TRACONs and tower cabs that control traffic

around busy airports will face even more responsibilities in the near future when broadened Mode

C transponder requirements become effective. Furthermore, many TRACONs would require capacity

enhancement to include the Mode C Intruder Alert

function. Currently, the New York TRACON

equipment is being upgraded for increased capacity, Mode C Intruder Alert, and better displays.

OTA finds that other TRACONs will need additional computer capacity to handle expected increases in transponder traffic levels without performance degradation, and still more capacity if

the Mode C Intruder Alert feature is included.

Funds for increasing equipment capacity at TRACONs

are included in FAA’s fiscal year 1989 budget request. The Mode C Intruder Alert, which will be

used at all ARTCCs, could be used at TRACONs

as well, but needs analysis and testing to ensure that

its false alarm rate is acceptable. Installation of the

Mode C Intruder Alert at TRACONs is expected

to be part of the 1988 version of the NAS Plan.

While recent legislation will require broader carriage of Mode C transponders by GA aircraft, some

aircraft will still not carry Mode C transponders.

An option is to continue to increase altitude-encoding transponder requirements, concurrent with increased ATC equipment capabilities and personnel,

to guard against accidental incursions into airspace

where radar coverage is provided and to provide the

maximum protection through TCAS.

Automation tools for controllers at all facilities–

airport tower cabs, TRACONs, ARTCCs, and the

Central Flow Control Facility–could assist in the

safe handling of higher levels of traffic and reduce

pressures on air traffic controllers. In particular, terminal automation development is a potential area

for improvement prior to AAS. While terminal

automation development has not previously been

well funded, additional funding is being sought by

FAA for fiscal year 1989. For the longer term, ATC

problems may worsen as traffic levels increase unless the infrastructure of the ATC system is upgraded. AAS is FAA’s long-term program to avert

ATC problems. In the interim, before AAS is fully

implemented, support to FAA for analysis to identify emerging operational problems and to establish parameters for solutions to the problems

would help facilitate adequate ATC system capabilities as the air transportation system evolves.

Timely, cost-effective solutions to ATC problems

must include both technological changes and support for related personnel needs. (See chapter 3 for

more discussion of ATC personnel problems.) AERA

offers potential long-term benefits for en route controllers through automation, but more work is

needed to understand both the system safety and

efficiency implications of AERA to clarify whether

AERA will facilitate safe control of higher traffic

levels.

Weather is a contributing factor in many aircraft

accidents, and sensors such as TDWR hold great

promise for improving safety through rapid detection of dangerous weather. The high cost of TDWR,

however, may preclude its use at all but the largest

airports, so other lower cost technologies for

microburst detection (in addition to enhanced

LLWAS) merit further examination. OTA finds

that improved training for pilots in use of weather

information available in the cockpit, and R&D

to develop message formats and workable air/

ground communications for weather information,

are at least as important as weather sensor development for improving aviation safety.

Current air/ground communications are not always adequate to support the needs of pilots for

both real-time ATC and real-time weather information. Providing ATC information to ensure separation between aircraft and issuing safety alerts are

the controllers’ first priorities, and controllers sometimes do not have time to transmit weather information to pilots or are distracted from transmitting

information by more urgent demands to separate

traffic. For the near term, better pilot training in

use of information from on-board weather radar

and from visual observations can compensate

somewhat for occasional lack of weather information from controllers. The FAA’s Windshear
161

Training Aid program, developed cooperatively with

industry, has features that are a step in this direction. For the longer term, automation and development of digital air/ground data links can eventually remove controllers from the process of

relaying weather information to pilots and can potentially reduce controller workload for ATC

messages. The Mode S data link can be integrated

with commercial data links to produce a very reliable system with excellent coverage and capacity.

However, in the past, digital communications have

been relegated by FAA to the distant future, and

commitment is needed to replace the current analog voice system. OTA concludes that R&D efforts

on data link services, human factors, and system

integration have a potentially high payoff for efficiency as well as safety. Both FAA and NASA

(which already has personnel, facilities, and equipment to do some of this R&D) have begun work

in this area.

TCAS has taken a long time to reach its present

stage of readiness for limited installation testing, and

whether TCAS introduces unexpected ATC problems and human factors questions remains to be

seen. Not all countries are satisfied with TCAS, and

requiring its use in the United States will not guarantee its eventual use everywhere. None of these

issues appears to be a crucial stumbling block to

TCAS.

Although the United States has had few recent

fatalities from collisions on the airport surface, a

number of nonfatal collisions and close calls have

occurred. As air traffic levels increase, the probability

of a disastrous ground collision will increase, lacking compensatory measures. The ASDE-3 radar,

currently under development, is one such measure,

but other means to improve ground collision safety

include improved signs on the airport surface, control lights at entrances to active runways, and more

vigilance by pilots during taxi operations. Congress

may wish to encourage FAA to expedite increased

ground collision safety through technological,

procedural, and training approaches, as well as

through ASDE~3 development. Short-term R&D

to improve sign symbology could provide the basis

for consistent standards for taxiway and runway

signs at all U.S. airports. If current tests are successful, stop/go bar lights and signal lights could be installed at entrances to major runways to augment

runway clearances from ground controllers. Additional controllers for airport towers would be needed

to operate the lights. Procedural rules could be

changed to require that both pilots and co-pilots

be free of other work while taxiing, and training for

pilots and controllers on preventing runway incursions could be increased.

Air traffic controllers at some en route facilities

now receive site-specific training at the FAA Academy in Oklahoma City, because of inadequate resources at the en route facilities. OTA finds that

improved simulation training for air traffic com

trollers could lead to more cost-effective ATC

training, both now and in the future, when further automation is introduced.

FAA has begun development of system-wide capacity models (NASPAC) to take into account traffic flows between airports. Continued emphasis on

analytical modeling to better understand capacity of the air traffic system would help FAA assume a leadership position in the future when difficult issues regarding capacity, safety, noise, and

airline scheduling arise.

The NAS Plan has suffered because requirements

for its technologies have changed since the Plan was

created in 1981. FAA, recognizing the emergence

of important near-term needs, has established an

interim support program. However, FAA has done

relatively little near-term or far-term research to support NAS developments. NASPAC and other operations research and analysis efforts could help FAA

identify emerging ATC problems and parameters

for solutions to the problems. An area for further

investigation is the use of modern prototyping and

test bed technology to help FAA evaluate alternative technological and operational solutions in a realistic way that encourages innovation and timel y

fielding of technology.
Chapter 8

Aircraft Technologies

Photo credit: Boeing Commercial Airplane Co.

Horizontal situation display for the cockpit
CONTENTS

Page

Regulation of Aircraft Technologies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ...........165

Airworthiness . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..................166

Equipment Certification Process .......,. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ...167

Simulators for Pilot and Mechanic Training . ................................169

The Future of Commercial Aircraft Technology. . ..............................170

Cockpit Technologies . . . . . . . . . . . . . . . . . . . . . ................................170

Advanced Materials for Aircraft . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ........171

New Aircraft Engine Types . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. ....172

Technologies and Training for Icing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. ....174

Crash and Fire Safety Technologies. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. ....175

Conclusions and Policy Options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. ....175

Figure

Figure Page

8-1. Controlled Flight Into Terrain: Descent and Approach Phase of Flight . .......166
Chapter 8

Aircraft Technologies

Technological advances have generated new types

of sophisticated and complex commercial aircraft.

Functions once performed by pilots using information provided by electromechanical displays are now

performed automatically, with information for the

pilot presented on electronic displays. New fly-bywire concepts sever the mechanical connection between pilot and the aircraft wing and tail. Dozens

of electronic devices monitor and control aircraft

components, and newer types of aircraft provide pilots or automated control devices such as computers

and actuators with enormous quantities of information. Simultaneously, at the other extreme, many

airlines are operating older types of aircraft, finding the high cost of new equipment prohibitive.

Thus, the commercial aviation industry uses a variety of aircraft technologies of various ages and

levels of sophistication—all regulated by the Federal

Government to assure the safety of the flying public.

This chapter examines the Federal Aviation Administration (FAA) rulemaking and enforcement

activities for new aircraft technologies, including

standardization across FAA directorates, technical

expertise and personnel levels, and inspector training. Because the future will bring new cockpit and

engine technologies and advanced materials, highspeed aircraft, and vertical and short takeoff and

landing aircraft, the implications of such technologies for safety and regulatory activities are also reviewed.

REGULATION OF AIRCRAFT TECHNOLOGIES

FAA rulemaking in areas of technology is often

controversial; parts of industry have, on occasion,

claimed that FAA has forced the development of

technology by proposing or suggesting a rule, often

at the urging of Congress or the National Transportation Safety Board. However, the point at which

a new technology is ready for implementation is

quite subjective. For instance, anti-misting kerosene

fuel was given a widely publicized crash test in 1984

with direct inference that a rule requiring its use was

forthcoming. The test did not go as planned, at least

in part, because the aircraft, controlled from the

ground, hit the target for the controlled crash a t

an angle. An engine was damaged and exploded,

igniting escaping fuel and creating an inferno. Temperatures within the cabin, however, remained

within the survivable range. The failed crash test

reinforced other evidence that, despite previous successes with smaller scale tests, anti-misting kerosene

was still a developmental substance, and further research was needed. Another example is flammability standards for cabin materials. An FAA rule requires that cabin materials in transport category

airplanes meet test criteria based on heat release as

a measure of flammability, with two steps to incorporation—August 1988 and August 1990. ] Some

industry sources have argued that materials meeting the criteria did not exist, at least at the time of

the rulemaking;2 in any case, meeting the criteria

will surely be costly to airlines and manufacturers.

Concerns have also arisen about the applicability

of the required test criteria, since they do not explicitly include smoke; FAA’s position is that heat

release alone is an adequate criterion because of a

correlation between heat release and smoke.

Congress plays a role in regulating aircraft technologies through its oversight of FAA and hearings

are often used to focus attention on regulatory issues that are important to Congress. Congress can

also pass laws that force technology requirements.

One example is the recent legislation, discussed in

chapter 7, requiring collision avoidance equipment

in commercial aircraft and expanding Mode C transponder requirements for general aviation (GA).

Congress also urged rapid completion of regulations

requiring the Ground Proximity Warning System

151 Federal Register 26206 UUIY 21, 19s~)

’51 Federal Register 26166 (July 21, 1987).

165
166

(GPWS). Although GPWS suffered from false-alarm

problems early on, it has demonstrably improved

safety for approach and descent phases of flight (see

figure 8-1).

Airworthiness

Government responsibilities for equipment airworthiness include development and administration of

safety standards for aircraft, engines, propellers, and

appliances such as avionics. Certification of aircraft

is at three levels: type, production, and original.

Type certification is FAA approval of the design of

an aircraft, production certification is approval of

the quality control system for production, and the

original certification process is the granting of approvals of the first and subsequent aircraft off the

assembly line. ]

In cases where the FAA Administrator finds that airworthiness regulations do not

contain adequate or appropriate safety standards for

an aircraft, aircraft engine, or propellor because of

‘U.S. Department of Transportation, Federal Aviation Administration, “Aircraft Certification Safety Regulatory Program Description,”

brwfing document, n.d.

I

4

3

2

1

0

1965 1970 1975 1960 1965

Year

KEY GPWS = Ground Proximity Warning System.

SOURCE Office of Technology Assessment, adapted from L.G. Lautman and P,L.

Gallimore, “Controlling the Crew Caused Accident,” Boeing Commercial Aircraft Co., May 1987

Prior to their use, commercial aircraft undergo extensive

testing, such as this water spray test

of the Boeing 767-200.

a novel or unusual design feature, he may prescribe

special conditions for the product to allow its certification. 4 FAA is also responsible for noise and

emission level certification of aircraft.

FAA rarely has the personnel or the specific technical expertise to certify an aircraft type without

assistance from the manufacturer. FAA relies heavily

on Designated Engineering Representatives (DERs),

who are experienced engineers employed and paid

by the manufacturer, but supervised by FAA, to

help in the certification process. DERs provide opportunity for conflicts of interest, although the

professionalism of the DERs and supervision by

FAA mitigate against this.5 Their experience in

working with FAA regulations often makes DERs

prized personnel for manufacturers.6

However, to ensure that certification requirements

are adequately applied, FAA requires technical expertise on its staff to provide oversight for DERs.

The largest pool of such expertise is in the ranks

of engineers at the manufacturers, and FAA has had

difficulty in attracting highly qualified and experienced engineers to work in certification in recent

+14 CFR 21,16 (Jan. 1, 1987).

5National Research Council, Improving Aircrafi Safety: FAA Certification of Commercial Passenger Aircrafi (Washington, DC: N’ational

Academy of Sciences, 1980), pp. 29-31.

~Wi]liam AshW,orth, office manager, Seattle Aircraft certification

Office, Federal Aviation Administration, Wrsonal communication, Aug.

4, 1987.
167

years. Some contend that this is due to the pay scale

for engineers at FAA which has not kept up with

industry, and because of limited career development

opportunities at FAA. 7 The pay scale for certification engineers applies to engineers at the National

Aeronautics and Space Administration (NASA),

the Department of Defense (DoD), and other Federal organizations, as well. FAA maintains that

broader systems knowledge is required of its certification engineers than of engineers at the other organizations and that FAA certification engineers could

be on a higher pay scale.8 FAA employs about 10

National Resource Specialists, who are experts in

particular areas, at a higher salary level.

FAA’s control over type certification is shared by

four of its regional offices, a decentralized organization that lends itself to internal FAA disagreements

over regulatory actions. An example is the Boeing

request to screen off two of the 10 exit doors on 747s,

discussed in chapter 3.

The FAA Associate Administrator for Aviation

Standards has recognized that the certification program is not standardized across directorates, is unable to keep up with technical developments because

of a shortage of expertise, and has human relations

problems and training limitations for certification

personnel. Project SMART is now under way to develop a master plan to address these problems and

upgrade the aircraft certification regulatory program.

So far, a job task analysis and management analysis for certification have been started. The knowledge gained from Project SMART has already begun to benefit the national training program, job

design and restructuring, and other areas through

its recommendations for improvement. Projec t

SMART has not yet received project funding, but

is supported by miscellaneous funds from othe r

projects .

9

Both Parts 121 and 135 prescribe minimum airplane instrument and equipment requirements ,

1 0

and the regulations contain the specification and

installation requirements for instruments and equipment. The major categories of instruments and

equipment specified in the regulations are: flight and

navigational equipment; engine instruments; emergency equipment; seats, safety belts, and shoulder

harnesses; public address and crewmember interphone systems; special instruments for operations

at night and under instrument flight rules or overthe-top conditions; oxygen and other protective

breathing equipment; radio equipment; weather detection equipment; flight and cockpit voice recorders;

and ground proximity warning devices. Carrier s

operating under Parts 121 and 135 are prohibited

from using airplanes unless certain instruments or

pieces of equipment, contained in a minimum equipment list for the aircraft type, are operable. However, there are numerous differences between the

Part 121 and Part 135 instrument and equipment

regulations. While many of these inconsistencies exist because of differing design and performance capabilities of large and small airplanes, certain pieces

of equipment required for Part 121 operations have

been intentionally excluded from Part 135, primarily for economic reasons that predate deregulation.

These inconsistencies have caused concern since deregulation for several fundamental reasons. First, for

some routes, Part 135 operations have replaced Part

121 operations. Second, the intent of Congress was

to not allow any diminution of safety because of deregulation. Third, code-sharing arrangements have

produced cases where passengers are not aware that

they will be flying with a Part 135 operator when

they buy a ticket from a major carrier. Regulatory

initiatives are under way to address flight and cockpit voice recorders, ground proximity warning devices, and crew interphone systems for Part 135 operations. 11

Equipment Certification Process

Aircraft engines and propellers are subject to the

same certification process as aircraft. Appliances,

such as avionics, are certified through the development of Technical Standard Orders. The technical

‘Ibid.

‘Dennis H. Piotrowski, program manager, Office of Airworthiness,

Federal Aviation Administration, personal communication, Sept. 29,

1987.

‘Ibid.

1014 CFR 121, Subpart K and 14 CFR 135, Subpart C (Jan. 1, 1987).

1 IExamples of other differences include: 1) regulations fOr protective

breathing equipment for flight crewmembers in pressurized aircrafi, required under Part 121, are not included in Part 135; and 2) although

airborne weather radar equipment is required for large transport category airplanes (20 seats or more) under Parts 121 and 135, multiengined

aircraft with 10 seats or more are required to have airborne thunderstorm detection equipment only.
168

basis for appliance certification is often the work of

standards organizations such as the Radio Technical Commission for Aeronautics (RTCA) and the

Society of Automotive Engineers (SAE). RTCA covers communications systems, while SAE covers a

wide variety of systems such as landing gear, oxygen equipment, aircraft instruments, and many

others. RTCA and SAE form committees of industry and government representatives to examine

standards for aircraft appliances, and produce documents which represent the consensus of the group.

FAA is under no legal obligation to use these documents, but frequently utilizes them because of the

technical knowledge they embody and because they

are the products of agreement between many disparate groups.12

Maintenance regulations for operations under

Part 121 and for operations using aircraft with 10

or more passenger seats under Part 135 are similar;

separate maintenance requirements for Part 135

operations using aircraft with 9 seats or fewer are

described below.13 Certificate holders, who are primarily responsible for the airworthiness of their aircraft, are required to establish maintenance organizations and programs, or arrange to have some

or all of the work performed by qualified outside

entities. 14

The operations specifications for each carrier describe the maintenance and inspection requirements

that must be met. Typically, these activities include:

routine aircraft inspections, tests, and servicing performed at prescribed intervals; scheduled maintenance tasks, such as replacement of life-limited items

and nondestructive testing; unscheduled mainte -

nance activities generated by inspections, flight crew

reports, or other analyses; specific engine, propeller, and appliance repair and overhaul tasks; and

major structural inspections and airframe overhauls.

Required inspection items, work elements that could

endanger the safe operation of an aircraft if imlzw/illiam G, Osmun, The Aurhority of Agreement: A History of

RTCA (Washington, DC: Radio Technical Commission for Aeronautics, 1985).

1~14 CFR 121, Subpart L and 14 CFR 135, SUbpm ] (bn. 1, 1987).

“A carrier authorized by the Federal Aviation Administration to

perform all maintenance and inspection activities required under Part

121 or 135 on its own aircraft or for other carriers or operators does

so under a Continuous Airworthiness Maintenance Program. See U.S.

Department of Transportation, Federal Aviation Administration, “Continuous Airworthiness Maintenance Programs,” Advisory Circular 120-

16C, Aug. 8, 1980.

properly done, are also specified. All maintenance

activities must be conducted in accordance with performance standards specified in 14 CFR 43, and

records must be kept of all work performed on an

aircraft.

Parts 121 and 135 regulations require that maintenance organizations be adequate to perform all

work and required inspections; and that inspection

and maintenance functions are kept separate below

the administrative control level. Mechanics and

repairmen employed by certificated carriers must

meet minimum certification requirements contained

in 14 CFR 65. In addition, carriers are required to

prepare detailed manuals for employees prescribing

methods, standards, and procedures for all maintenance. Some airlines use the job cards of the aircraft manufacturer’s maintenance manual without

modification for their own program; this saves the

airline the cost of having to develop its own system.15 Airlines may not perform major repairs on

airplanes unless so authorized by FAA, *6 but there

are ambiguities in the definition of “major repair.”17 Airlines are required to establish training

programs to inform maintenance and inspection

personnel about procedures, techniques, and new

equipment and to develop an internal audit system

to ensure quality control.

Although work limits have not been prescribed

for maintenance personnel under Part 121, existing

regulations require that they be relieved from duty

for at least 24 consecutive hours during any 7 consecutive days or an equivalent period within any

calendar month. A similar provision has not been

included in the Part 135 regulations.18

Maintenance requirements for Part 135 operations

using aircraft with nine seats or fewer are less extensive. 19 These operators are permitted to follow

the maintenance requirements in 14 CFR 91 for GA

aircraft, unless FAA determines that a more rigorous program is necessary. In these instances, oper15DavidSayre, supervisor} Maintenance and Ground Systems, Boeing Commercial Airplane Co., personal communication, Aug. 3, 1987.

1~14 CFR ch. 1 SFAR.36 (Jan. 1, 1987), P P. 288-290.

ITWilliam C. Keil, USAir and Melvin C. Beard, Federal Aviation

Administration, in U.S. Congress, Office of Technology Assessment,

“Transcript of Proceedings-OTA Workshop on TechnoloW in Commercial Aviation Safety,” unpublished typescript, July 1, 1987, pp.

227-229.

1814 cm 121.377 Uan. 1, 1987).

1 914 CFR 135.411 (Jan. 1, 1987).
169

ations specifications are amended to require a program that contains: instructions and procedures for

aircraft inspections, specifying parts and sections of

airframes, engines, propellers, rotors, and appliances;

schedules for performance of aircraft inspections in

terms of time in service, calendar time, or number

of system operations; and instructions and procedures for recording discrepancies found during inspections, corrections, or maintenance deferrals.

Principal Maintenance Inspectors (PMIs), who inspect airlines’ maintenance operations, are stationed

at FAA field offices. PMIs also participate with factory maintenance specialists assigned to the aircraft

manufacturer in an FAA review board to develop

minimum maintenance requirements for aircraft

types. Questions have been raised over the adequacy

of FAA surveillance of airline operations and the

capabilities of inspectors to monitor maintenance

programs and approve waivers or deviations from

operating specifications. For further discussion of

the adequacy of the number of FAA inspectors and

FAA training programs for inspectors, see chapters

3 and 5.

An aircraft or part manufacturer may send airlines a service bulletin recommending a change in

a configuration or an inspection or maintenance

procedure to be carried out by the maintenance department. More urgent service bulletins, called alert

service bulletins, usually evolve into Airworthiness

Directives (ADs) issued by FAA, which require

changes that must be made to retain aircraft certification. Sometimes extensive negotiation is required between an airline and FAA to ensure that

an airline receives credit for promptly responding

to a service bulletin, prior to the issuing of the

AD. 20 In other cases, however, FAA and a manufacturer have utilized the efforts of an operator, incorporating the procedures into a service bulletin

and AD.21

Simulators for Pilot and Mechanic

Training

Simulators are currently used for initial, transition, and upgrade training, recurrent training, and

“’Willlam C. Keil, staff director, Engineering and Quality Assurance,

~lSAlr, Inc., ~er$(>na] communication, Oct. 14, 1~87.

L ‘Da\’ld Letterer, Alr Transport Association of America, letter to

OTA, Jan. i, 1988.

proficiency checking of pilots. The efficiency, speed,

safety, and low cost of simulator training compared

to training in aircraft makes it attractive to airlines,

as they order new aircraft and new aircraft types

and recruit and train pilots. Simulators become more

important from a safety standpoint as airlines must

hire less experienced pilots, because simulators can

provide experience in dealing with many safetycritical situations in a short time.

In addition to the full-motion, full-visual training simulators provide, a substantial amount of

training is done in fixed-base cockpit training devices with no simulated scenes outside the cockpit.

Personal computers (PCs) with graphics and touchscreen capabilities are also used extensively for air--

craft systems and avionics training, typically one system at a time. The fixed-based cockpit training de--

vices and PC-based training aids save precious time

in the expensive full-motion simulators.

In general, a full-motion, full-vision simulator with

a complete mock-up of the cockpit and avionics costs

on the order of $10 million, regardless of aircraft

type. Because of this high cost, airlines that buy

simulators usually intend to sell simulation services

to others, except for large airlines that have many

aircraft of the same type. z: Some airlines also send

pilots to aircraft manufacturers for simulator training.

‘:Mark Lambert, “Simulator Makers Face NW Market Conditions,”

Interatia, vol. 42, January 1987, pp. 75-76.

The exterior of a full-motion pilot training simulator
170

Part 121 operators use full-motion simulators extensively, but Part 135 operators generally do not,

because of the prohibitively high cost of the simulators. Federal regulations spell out requirements for

Part 121 operators on simulator capabilities and

what they can be used for, but are not specific on

simulator use by Part 135 operators.23 However,

FAA recently released advisory circulars which

delineate Part 135 requirements for advanced training devices (ATDs, which are essentially simulators

airlines have been arguing for use of ATDs since

1984. 25

Simulators for aircraft maintenance personnel are

used to provide systems overviews and demonstrations, and for practice at equipment analysis, fault

reporting, and diagnosis. Computer-aided training

using microprocessors is also used at certain stages

of training.26

without motion or visual simulation), and state

where ATDs may be used instead of flight in an actual aircraft for training and testing.24 The regional

2]14 CFR, Ch. 1, Part 121, Appendix H (Jan. 1, 19s7). zJRlchard L collie, Technical Services, Regional Airline Associa24u s Departmentof Trans~rtation, Federal Aviation Adminis- . . tion, personal’ communication, Aug. 17, 1987.

tration, “Advanced Training Devices (Airplane Only) Evaluation and 26R. O. Jollie, “Digital Avionics Training,” Boeing Airliner, AprilQualification,” Advisory Circular No. 120-45, May 11, 1987. June 1987, p. 21.

THE FUTURE OF COMMERCIAL AIRCRAFT TECHNOLOGY

The future will bring changes in commercial aviation technology, including further development and

use of electronic systems for sensing the environment and control of the aircraft, new aircraft engine types, use of composite materials in aircraft construction, and new types of aircraft such as tilt-rotor

and supersonic/hypersonic aircraft. Most of the

changes will not be motivated primarily by concern

for safety, but by the desire for efficiency and speed

of travel. Significant changes are also likely in the

air traffic control (ATC) system, bringing more automation, automatic decisionmaking, and methods of

dealing with limited airport capacity. The changing state of technology and the airspace system require continuous safety oversight by government

and industry, so that efficiency and speed are not

gained at the expense of safety. Advanced technologies will present significant challenges to the government in terms of certification and flight safety.

In particular, as automated systems take over more

tasks, including decisionmaking, that are now performed by humans, the interaction between humans

and advanced equipment will need special attention.

Cockpit Technologies

The current trends in cockpit technology are

toward more automation and advanced displays for

pilots, driven primarily by the push for two-pilot

cockpits to save airlines the cost of a third crewmember. More information is available to pilots from new

sources, and new systems can provide quick, automatic reaction within safe aircraft performance limits

to events such as windshear encounters. Moreover,

new technologies offer increased equipment reliability, trouble-shooting capability, and reduced

weight, compared with older technologies. For all

these reasons, the trends will continue into the foreseeable future.

Some areas of current research and development

(R&D) include liquid crystal flat-panel displays,

head-up displays, voice recognition systems, fly-bywire and fly-by-light, and artificial intelligence (AI)

applications. Liquid crystal displays offer the potential for high luminance and resolution using little

power. Powered by lithium-cell batteries, such displays could be useful as standbys in case of engine

or power system failure. However, the displays are

very temperature sensitive and have a slow transition time, weaknesses that are subjects of current

R&D.

27

Fly-by-wire technology is included on the Concorde, the Boeing 757 with the Pratt and Whitney

2037 engine, and the Airbus 320. Fly-by-light techzT]ohn T Merrifield, “TranSWrt Manufacturers Press for Aumrnawd

Cockpits, ’’”Aviation Week & Space Technology, Mar. 10, 1986, p. 247.
171

nology may appear on the Boeing 7J7, if Boeing completes its development of that airplane. These technologies replace most of the mechanical links from

the pilot’s controls to the wings and tail by electrical wire or optical fibers. Fly-by-wire and fly-by-light

save weight, reduce maintenance, and eliminate the

variabilities of hydromechanical systems, thereby

making airplanes easier to operate and reducing the

rate of increase of aircraft operating costs. Furthermore, computers can analyze information about the

behavior of the airplane and, through the fly-bywire or fly-by-light mechanisms, physically prevent

a dangerous maneuver. Currently, research is taking place in the areas of stick configuration, stick

“feel,” and how to handle cases where both pilots

use the controls simultaneously .28

Most research on AI applications for the cockpit

takes place in a military context. For example, the

Defense Advanced Research Projects Agency sponsors the Pilot’s Associate program to evaluate and

demonstrate the utility of AI and expert systems

techniques for military applications. Applications

under examination include monitoring aircraft systems (i.e., the role of the flight engineer), mission

planning and replanning, external situation assessment, and devising optimum strategies to deal with

external threats.29 NASA-Ames is also pursuing a

program to optimize the guidance and control of

aircraft (including ATC) using AI techniques. Although the program may have civil applications, its

basic thrust is toward military aircraft.30 Potentially, AI techniques could find application to civil

aircraft in monitoring aircraft systems and dealing

with complex weather information.

Advanced Materials for Aircraft

Many new types of advanced materials may be

used in future aircraft. Composite materials are attractive because of their strength/stiffness properties and their lighter weight and corrosion resistance.

Other advanced materials include aluminum alloys,

z8John T. Merrifield, ‘[NASA/Douglas Team Studies Fly-by-wire

Control Concepts,” Aviation Week & Space Techno)~, Oct. 27, 1986,

p. 38.

“Aviation Week & Space Technology, “DARPA’s pilot’sASSOCIate Program Provides Development Challenges, ” Feb. 17, 1986, p. 45.

‘@John T. Merrifield, “AI Research at Ames Focuses on Increased

Crew Effectiveness,” Aviation Week & Space Technology, June 2, 1986,

p. 73.

advanced ceramics, special high-strength steels, titanium/aluminum alloys, and rigid-rod polymers,

which consist of small rods of high-strength poly

-

mer embedded in a tough polymer matrix. Improved

material coatings may also be used in stressful environments, such as for turbine engine blades.31

Processing and assembly techniques are also advancing in the areas of powder metallurgy, precision die casting and forging, lightweight metal web

casting, superplastic forming, and diffusion bonding. Powder metallurgy uses highly-engineered powders at high pressure to form precision metal parts

that do not require machining. Powder metallurgy

permits use of superalloy developed for high temperature service and severe mechanical stressing with

high surface stability. Use of cast metal web parts

is currently limited by Federal regulations, which

apply a safety margin to cast parts that increases

their weight. Superplastic forming produces 1arge

changes in the shape of material under conditions

of high temperature and low pressure. Diffusion

bonding joins parts at high temperature and pressure without melting, because metal atoms diffuse

across the solid surface.32

New types of materials will be used in propulsion

systems and airframes of subsonic aircraft primarily to gain fuel efficiency. Composite materials are

already used in some large commercial aircraft, including the Boeing 757 and 767 in ailerons, rudders,

and certain landing gear doors, although not for any

critical structures. 33 For supersonic aircraft, advanced

materials will be used where the aircraft surface

reaches high temperature and in propulsion systems

for weight reduction and resistance to high temperatures. 34

Research is under way to examine the implications

of using advanced materials for crashworthiness;35

“Morris A. Steinberg, “Materials for Aerospace,” Scientific American, October 1986, pp. 67-72.

‘

z

Pierre Condom, “Forming Aircraft Structural Components: A

Slow Revolution,” ]nreravia, vol. 41, December 1986, pp. 1429-1430.

‘~U.S. Congress, OfYice of Technology Assessment, New SrructuraJ

Materials Technologies: Opportunities for the Use of Ad\anced Ceramics and Composites-A Technical Memorandum (Springfield, VA:

National Technical Information Service, September 1986).

‘Steinberg, op. cit., footnote 3 I.

~JEdward H phllllps, “NASA, Army Testing Composite Airframe

Crashworthiness,” Aviation Week & Space Technology, Sept. 28, 1987,

p. 61.
172

continuing this type of research is important to ensure that FAA has sufficient knowledge to regulate

the materials for safe use and maintenance. Composite materials bring a set of unique properties, such

as vulnerability to impact, where surface inspection

cannot detect subsurface delamination, and new

technologies for inspection will be needed. The

proliferation of these new materials will require the

certifying and inspecting agency to have considerable expertise in their properties at its disposal, and

at present FAA has one National Resource Specialist

in nonmetallic advanced materials and one in fracture mechanics and metallurgy.

New Aircraft Engine Types

Turbofans are the engines used in most commercial jet aircraft today. While improvements in materials and computer modeling design techniques will

allow more efficient turbofans to be built, ultra-high

bypass (UHB) engines are likely to surpass turbofans

by sometime in the 1990s. Current UHB engines

are limited to speeds under Mach 0.80 and therefore require further development for long-range applications. (The Boeing 747, for example, currently

flies at speeds of Mach 0.84 to 0.85 where Mach 1

is the speed of sound—about 660 mph at cruise altitudes.) Advanced, high-speed propellers in UHB

engines improve the fuel efficiency of the propulsion system by as much as 25 percent compared to

current turbofans, potentially cutting by as much

as 10 percent the direct operating costs of airlines.36

UHB engines raise safety concerns in areas such

as bird strike and icing effects, while their external

propellers pose potential safety hazards because of

the possibility of penetrating fuselage, flight controls,

or critical components in case of a malfunction. This

problem is partially mitigated by the relatively light

weight of the small blades—one manufacturer has

developed UHB engine blades weighing only about

10 pounds each. Other safety-related aircraft design

features may include separate routing of connections

to the aircraft’s tail structure and locating the cabin’s

aft pressure bulkhead forward of the blades’ plane

of rotation to prevent rapid decompression in the

event of blade penetration.37

~aAviation Week & Space Technology, “Ultra-High Bypass Engines

Will Enter Commercial Service by Late 1990s,” Mar. 9, 1987, p. 189.

‘TAviarion Week & Space Technology, “No. 2 UDF Engine Prototype Will Fly on MD-80 by June,” Apr. 13, 1987, p. 58.

The more distant future may bring new types of

engines for use in supersonic and hypersonic aircraft. (Hypersonic refers to speeds five or more times

the speed of sound in air.) The turboramjet engine

is being studied for hypersonic application. This type

of engine would operate as a turbofan for speeds up

to Mach 3.5 and as a ramjet at higher speeds. Problems with the turboramjet engine include noise and

the need to use endothermic fuels which can absorb thermal energy from the surface of the aircraft

produced by aerodynamic heating.38 For speeds

above Mach 6, the supersonic combustion ramjet

(scramjet) is being investigated by NASA and

others. 39

Advanced high-speed aircraft include supersonic

and hypersonic aircraft. Past experience with highspeed aircraft includes the Concorde and Supersonic

Transport (SST) programs. The Concorde was developed by the British and French during the 1960s

and 1970s. During the development cycle, sales estimates for Concorde ranged between 100 and 500,

but only 16 Concordes were actually built, at a loss

of over $3 billion. Although the Concorde was an

economic failure, some technology was transferred

to other aircraft projects, particularly the French Mirage fighter airplane.40

The SST program was undertaken in the United

States in 1963 and terminated in 1971, after a total

expenditure of about $1 billion. Sales estimates during the program were originally from 25 to 125, and

swelled to over 800 at one point, but no aircraft were

built. The basic reasons for termination concerned

the noise and alleged health consequences of the

SST, the social implications of a taxpayer-funded

project to benefit only a few well-off people, and

technical difficulties: cost estimates by 1971 had

grown considerably beyond the original estimates.4l

‘sPaul Proctor, “Advanced Fuel Systems Crucial to High-Speed

Transport Progress, “ Aviation Week& Space Technology, Feb. 9, 1987,

p. 45.

“%aymond S. Colladay, associate administrator, Office of Aeronautics and Space Technology, National Aeronautics and Space Administration, testimony before U.S. Congress, House Committee on Science and Technology, Subcommittee on Transportation, Aviation and

Materials, July 24, 1985.

4’W. S, Congress, Office of Technology Assessment, Impact of Advanced Air Transport Technology: Part 1, Advanced High-Speed Aircraft (Springfield, VA: National Technical Information Service, April

1980).

411bid.
173

Since the SST, there have been many advances

in computers for wing design, and materials and

propulsion systems, which have given impetus to

further R&D in hypersonic aircraft, although primarily for military application. The National AeroSpace Plane (NASP) project is a joint DoD/NASA

program to develop a research aircraft with hypersonic cruise and single-stage-to-orbit capabilities.

NASP is currently in a conceptual stage, and speeds

up to Mach 25 are projected, Applications that could

be developed out of the NASP include strategic

reconnaissance aircraft, a replacement for the space

shuttle, and civil hypersonic transport aircraft.42

NASA has also sponsored studies to examine the

viability of SST aircraft around the year 2000. The

studies suggest that transports in the speed range

of Mach 2 to Mach 6 may be commercially viable,

but there appear to be diminishing productivity

returns at Mach numbers greater than six.43

Technical problems with supersonic aircraft include takeoff noise and sonic boom, possible depletion of the ozone layer, and their very high specific

fuel consumption at low speeds. They could not be

kept cost-effective for very long in holding patterns

at low speed because of high specific fuel consumption and because the value of supersonic travel

would quickly dissipate. Capacity problems at many

U.S. airports along the coasts are already severe,

and may worsen, so airport delays may seriously reduce the advantages of supersonic travel. Also, noise

is a major issue with many citizens who live near

airports, and is likely to remain so. For all these reasons, the future of commercial supersonic transportation is very uncertain.

Vertical takeoff and landing (VTOL) and short

takeoff and landing (STOL) aircraft offer the possibility for landing in and taking off from downtown

areas of cities, if appropriate sites can be found at

reasonable cost. Passengers on the V/STOL aircraft

‘]John D. Moteff, Congressional Research Service, The Library of

Congress, “The National Aero-Space Plane Program: A Brief History,”

issue brief 88-146 SPR, Feb. 17, 1988.

~] Louis J. Wl]llams, National Aeronautics and Space Administration, “High-Speed Civil Transport Study Status Report,” briefing document, n.d.; Boeing Commercial Airplane Co., “High-Speed Civil

Transport Studies Phase II Oral Report,” briefing document, Mar. 17,

1988; McDonnell Douglas, “High-Speed Civil Transport Studies NASA

Contract NAS 1-18378 Phase II Summary Review,” briefing document,

Mar. 17, 1988.

could be transported directly to their final destination, or to a remote airport for a flight on a subsonic or supersonic airliner. The helicopter is one

example of a V/STOL aircraft, but its current speed

and fuel efficiency limitations prevent economic use

for routine passenger service. Efforts to improve on

the basic helicopter design to provide high-speed

V/STOL travel has resulted in two practical designs:

the tilt-rotor and the X-wing. Both designs are in

R&D for military applications with civilian certification criteria in mind.

The tilt-rotor aircraft is a winged aircraft with two

large rotors on the wings that can tilt to either a

helicopter position for takeoff (with a horizontal

plane of rotation) or a fixed-wing position for cruising (with a vertical plane of rotation). DoD is funding development of the V-22 Osprey tilt-rotor aircraft

for military application. Six European companies

have begun preliminary studies of a tilt-rotor aircraft for civil applications called Eurofar. Tilt rotors

have been flown before, and the main technological problem with commercial application is providing improved performance and reduced weight.

Some projections indicate that a market for tilt-rotor

service exists in the Northeast United States, and

service could begin as soon as the 1990s provided

that the proper infrastructure is in place to support

the operations.44

The X-wing aircraft accomplishes vertical or short

takeoff with helicopter blades, and uses the blades

as an X-shaped wing when cruising. The blades must

stop in order to cruise, and the conversion from

takeoff to cruise configuration has not yet been

mastered. The X-wing concept is under development

by Sikorsky Aircraft, following R&D by NASA,

the Army, and Sikorsky, and the first flight of a

demonstrator could take place around 1990. If successful, the X-wing aircraft could achieve higher

cruising speeds than the tilt-rotor.45

If used commercially, V/STOL aircraft would fly

across the centers of cities, so safety and reliability

considerations are especially important. Specifically,

q+Hoyle, Tanner & Associates, inc . t “VTOL Intercity Feasibility

Study,” prepared for The Port Authority of New York and New Jersey, July 1987.

4JAv1ation Week & Space TWhno]oW, “NASA Rotor systems Research Leads to X-Wing VTOL Aircraft Design,” June 2, 1986, p. 22;

and Steven Ashley, “X-Wing Aircraft,” Popular Science, July 1987, p. 48.
174

Photo credit: Federal Aviation Administration.

The XV-15 tilt rotor technology demonstration aircraft has

been flying successfully since 1977.

transmission systems of tilt-rotor aircraft must be

extremely reliable, since a transmission failure could

cause a catastrophic desynchronization of the rotors, at least in the context of current design thinking. Public acceptance of new V/STOL concepts in

terms of safety will be necessary for their success.46

Technologies and Training for Icing

Since 1975, four fatal Part 121 accidents have

occurred in which aircraft icing during takeoff has

been a major causal factor. Thus, improvements in

detecting and removing aircraft ice prior to takeoff

have a potentially great safety payoff.

With the exception of analyses and testing to

ascertain flight characteristics of an aircraft during

flight, all analyses and aircraft certification testing

required by FAA are conducted with a clean aircraft flying in a clean environment. Thus, current

certification procedures do not require tests for airworthiness of an aircraft with ice on its surface prior

to takeoff.47 FAA regulations do not require use of

any de-icing technology before takeoff, but forbid

takeoff when frost, snow, or ice is adhering to the

wings, control surfaces, or propellers of the aircraft. 48 (Part 135 regulations also forbid takeoff

when frost, snow, or ice adheres to a number of

other surfaces.) In general, U.S. carriers rely on pilots to observe their own aircraft for signs of adher-

‘eMarc Granger, “For or Against the Tilt-Rotor? Two Views of the

Enrofar Project,” lnteravia, vol. 42, June 1987, pp. 649-650.

‘;U.S. Department of Transportation, Federal Aviation Administration, “Hazards Following Ground Deicing and Ground Operations

in Conditions Conducive to Aircraft Icing, ” Advisory Circular 20-117,

Dec. 17, 1982.

%ee 14 CFR 121.629, 135.227, and 91.209 (Jan. 1, 1987).

ing ice. FAA has published advisory documents that

provide guidance to airlines and pilots on the icing

phenomenon, on technologies for ice removal, and

on estimated safe holdover times for aircraft that

have been de-iced.49 Additional basic and recurrent training for pilots is a relatively low-cost method

for helping prevent icing accidents. FAA is beginning efforts to enhance training programs for pilots

through media such as video presentations.

For roughly 15 years, some European airlines have

successfully used more viscous de-icing fluids than

those used in the United States; these are called

Association of European Airlines (AEA) type-II

fluids. Longer-lasting than fluids used in the United

States, they are fragile and must be handled carefully to avoid destroying their desirable characteristics. They stick readily to aircraft surfaces and may

interfere with the aerodynamic characteristics of the

aircraft. AEA type-11 fluid is, however, designed so

that its viscosity breaks down with shear force, so

that the movement of the aircraft tends to knock

off the fluid. Because humidity/temperature trends

in the United States differ from those in Europe,

U.S. airlines might not be as successful as European

airlines with type-11 fluids; U.S. operators would

need time to learn to use type-II fluids effectively .50

Despite these limitations, Federal Express has recently begun using the type-11 fluids in its aircraft

operations. FAA does not plan to develop more specific regulatory guidelines on de-icing technologies,

and regulations requiring use of high-viscosity deicing fluids would impose large costs on airlines and

providers of de-icing service for new equipment,

operational procedures, and training. FAA regulations might discourage development of more advanced types of de-icing fluid, which would not meet

the requirements of the regulation, and other actions can be taken to address icing problems.

Most U.S. airlines de-ice aircraft from trucks at

departure gates, after which the aircraft must taxi

to the runway entrance and may be delayed waiting for other aircraft to take off. If ice forms on the

aircraft during this time, the pilot must taxi back

to the gate for de-icing again. At several foreign airwu s Department of Transportation, Federal Aviation Adminis- . .

tration, op. cit, footnote 47.

%ichard Adams, national resource specialist for Aircraft Icing, Federal Aviation Administration, personal communication, Feb. 23, 1988.
175

ports, including Montreal, fixed-base facilities have

been set up near the end of a runway to permit deicing nearer to the time of intended takeoff. One

U.S. airline has a fixed-base de-icing facility at Denver Stapleton Airport. Operation of fixed-base facilities in the United States could be limited by liability concerns–most large U.S. airlines do their

own de-icing and so do not now have this problem.

Such facilities, if their use were mandated, could also

limit traffic flow at congested airports.

Another possibility is remote de-icing shortly before takeoff from trucks located near the entrances

to runways, already a trend, although many airports

are limited by insufficient apron space for de-icing

trucks to travel and operate. Federal funds could

be allocated from the Aviation Trust Fund to expand aprons near entrances to runways and remote

de-icing sites to allow mobile de-icing equipment to

move and operate.

Lights installed near the airport surface could help

pilots see the surfaces of the aircraft better, and qualified ground personnel could examine surfaces not

visible to the pilots. Another approach to reducing

the icing hazard before takeoff is to use icing sensors on the aircraft surface. Sensors are available,

but they pose problems, because they detect ice only

at specific areas on the aircraft surface, and pilots

may rely heavily on them without proper training.

Given the many possibilities for addressing the

icing hazard, FAA could develop a plan for icing

similar to the Integrated Wind Shear Program Plan.

The best first step could be a training program for

pilots and technicians, developed in cooperation

with industry. Technological and infrastructure approaches to reducing the icing hazard could also be

evaluated for their impact on safety, cost to government and industry, operational factors, and time

to implement.

Crash and Fire Safety Technologies

Advances have been made in recent years in developing and implementing technologies to reduce

risk to passengers in the event of a crash or in-flight

fire. Some technologies, such as smoke hoods, are

controversial because their use could have unintentional negative side effects for safety (e.g., putting

on smoke hoods could slow passengers’ egress from

the cabin after a crash) .51 Thus, careful research by

the Federal Government is needed to evaluate potential crash and fire safety technologies; this research is performed at FAA’s Technical Center in

Atlantic City, New Jersey.

Areas for further investigation include aircraft and

aircraft engine structural integrity, improved fireand smoke-resistant materials for aircraft interiors,

improved smoke detection and fire containment systems (particularly for in-flight fires), automated systems to aid pilots in detecting and responding to

in-flight fires, and advanced fuels with low flammability.

Although technology can improve crash and fire

safety, regulations requiring these technologies will

have economic and other effects on aircraft manufacturers, airlines, and passengers. For example, the

FAA rule to require cabin materials in transport category aircraft that meet a test criterion based on heat

release52 will have significant impacts on design

and construction of aircraft interiors. Cost-benefit

analysis can shed light on difficult decisions regarding regulations for crash and fire safety technologies,

but other types of judgment are necessary in balancing the many disparate considerations.

5iBron Rek, “Escape From Burning Cabins: Are Smoke Hoods the

Answer!” Interavia, vol. 42, January 1987, pp. 3738.

5L51 Federal Register 26206 (July 21, 1987).

CONCLUSIONS AND POLICY OPTIONS

FAA has occasionally attempted to push indus- dustry to develop or implement new technology that

try to develop and/or implement new safety tech- will lead to greater public safety.

nologies. The point at which a new technology is

ready for implementation is inevitably subject to a As the aviation industry continues to undergo

good deal of disagreement. At times, government technological advances and changes, FAA needs

requirements can act as a forcing mechanism on in- adequate numbers of expert technical personnel and
176

training capabilities for new staff not currently available to it, because funding resources are not sufficient to attract trained experts from industry. FAA

programs such as Project SMART and National Resource Specialists are steps to address this issue. The

future will bring new and increasingly sophisticated

commercial aviation technologies, many of which

will be introduced not for the sake of safety, but

for the economic benefits they promise. However,

many hold the potential for decreasing accident risk.

OTA finds that, in the long term, FAA will need

greater expertise on its staff in areas of new aviation technology to provide oversight comparable

to today ’s. Congress may wish to consider make

ing additional funding available to bolster FAA’s

technical staff.

Part 135 regulations have weaker minimum im

strument and equipment requirements than Part

121. This is significant because, since deregulation,

Part 135 operations have replaced Part 121 operations over some routes, and code-sharing arrangements have created situations where passengers are

not aware they will be flying on a Part 135 operation. One policy option is to eliminate the differences between Parts 121 and 135; however, the economic consequences for Part 135 operators could

be serious. Another option is to attempt to identify specific hazards in Part 135 operations, and to

rectify the most serious hazards through cost-effective measures as part of overall system safety management.

Aircraft icing before takeoff is an important

weather hazard. Better training for pilots and technicians appears to be the most cost-effective nearterm approach for reducing the icing hazard to aircraft before takeoff. For the longer term, greater

use of advanced de-icing fluids and de-icing facilities located near the entrances to runways offer

possible improvements, but the economic and

operational consequences of using these technologies need to be weighed carefully. The Aviation

Trust Fund could be tapped to support construction of wider aprons on runway ramps which would

help facilitate use of de-icing vehicles near entrances

to runways. Sensors for detection of ice on the aircraft is another approach, but has operational liabilities if pilots rely too heavily on them. FAA has

begun to increase industry awareness of icing problems through bulletins and advisory circulars. An

additional option is for FAA to work with industry to develop an integrated plan for training and

other improvements in icing safety. FAA’s integrated windshear plan, with its heavy participation from many industry groups, is a good model

for this option.
Appendixes
Appendix

List of Acronym

A

s

AAS –Advanced Automation System

AAT –Associate Administrator for Air Traffic

ACARS –ARINC Communications Addressing

ACAS

AD

ADA

ADAP

AEA

AERA

AI

AIDS

AIROPS

ALPA

ARINC

ARTCC

ASAS

ASDE

ASRP

ASRS

ATC

—

and Reporting System

–Air Carrier Analysis System

—Airworthiness Directive

–Airline Deregulation Act

–Airport Development Aid Program

—Association of European Airlines

—Advanced En Route Automation

—artificial intelligence

–Accident/Incident Data System

–Air Operator Data System

–Air Line Pilots Association

–Aeronautical Radio, inc.

–Air Route Traffic Control Center

–Aviation Safety Analysis System

–Airport Surface Detection Equipment

–Aviation Safety Reporting Program

–Aviation Safety Reporting System

—air traffic control

ATD —advanced training device

ATCRBS –Air Traffic Control Radar Beacon

ATIS

AVN

AVS

CAA

CAB

CAMI

CERT

CRM

CRS

CWSU

DER

DOT

DYSIM

EIS

FAA

FAR

FSF

FSS

GA

GAO

GOES

System

–Automated Terminal Information

Service

–Aviation Standards National Field

Office

–Aviation Standards

–Civil Aeronautics Authority

–Civil Aeronautics Board

—Civil Aeromedical institute

–Computer Enhanced Radar Training

—cockpit resource management

—computerized reservation system

–Center Weather Service Unit

–Designated Engineering Representative

–U.S. Department of Transportation

–Dynamic Simulation

–Enforcement Information System

—Federal Aviation Administration

–Federal Aviation Regulation

—Flight Safety Foundation

—Flight Service Station

—general aviation

–U.S. General Accounting Office

–Geostationary Operational

Environmental Satellite

GPWS —Ground Proximity Warning System

HF –high-frequency

IFR —instrument flight rules

ILS –Instrument Landing System

IOP —input/output processor

LLWAS –Low Level Windshear Alert System

LOFT –line-oriented flight training

LPP —labor protective provisions

MAC –Military Airlift Command

MLS —Microwave Landing System

MTMC —Military Traffic Management Command

NAS —National Airspace System

NASA –National Aeronautics and Space

Administration

NASP –National Aero-Space Plane

NASPAC —National Airspace System Performance

NATA

NATI

NMAC

NTSB

NWS

OMB

OSI

OST

PC

PMI

R&D

RAA

RSPA

RTCA

SAE

SDRS

SST

STOL

TCA

TCAS

TDWR

Capability

—National Air Transportation Association

—National Air Transportation Inspection

Program

—near midair collision

–National Transportation Safety Board

—National Weather Service

–Office of Management and Budget

—Open System Interconnection

—Office of the Secretary of Transportation

—personal computer

—Principal Maintenance Inspector

—research and development

—Regional Airline Association

—Research and Special Programs

Administration

–Radio Technical Commission for

Aeronautics

–Society of Automotive Engineers

—Service Difficulty Reporting System

–Supersonic Transport

—short takeoff and landing

—terminal control area

—Traffic Alert/Collision Avoidance

System

–Terminal Doppler Weather Radar

TRACON–Terminal Radar Approach Control

UHB —ultra-high bypass

VFR —visual flight rules

VHF —very-high frequency

VTOL —vertical takeoff and landing

WPMS –Work Program Management System

179
Appendix B

Workshop

and Contri

Participants, Reviewers,

butors

Participants in Human Factors in Commercial Aviation Safety Workshop

May 28, 1987

John Lauber, Workshop Chairman

National Transportation Safety Board

Charles Billings

Aerospace Human Factors Research Division

Ames Research Center

National Aeronautics and Space Administration

Robert G. Buley

Flight Standards

Northwest Airlines, Inc.

Frank Celona

International Association of Machinists and

Aerospace Workers

Delmar M. Fadden

Flight Crew Operations Requirements

Boeing Commercial Airplane Co.

John Fredericksen

Regional Airline Association

R. Curtis Graeber

Aerospace Human Factors Division

Ames Research Center

National Aeronautics and Space Administration

Mitchell Grossberg

Air Traffic System Resource Analysis Division

Federal Aviation Administration

George A. Hof, Jr.

Flight Operations

American Airlines,

Clyde Kizer

Inc. Flight Academy

Maintenance and Operations Division

United Airlines

James McIntyre

Air Line Pilots Association

Louis M. McNair

Air Line Pilots Association

Kenneth J. McNamara

Commercial Aviation Programs

SimuFlite Training International Division

The Singer Co.

James T. Muldoon

Aviation Technical Services

Port Authority of New York and New Jersey

John J. Nance

Consultant and Author

Tacoma, WA

Michael J. Pangia

Smiley, Olson, Gilman, and Pangia

William T. Shepherd

Biomedical and Behavioral Science Division

Office of Aviation Medicine

Federal Aviation Administration

Robert J. Tibor

Rockwell International

Collins Air Transport Division

Guice Tinsley

Flight Technical Programs Branch

Federal Aviation Administration

Earl L. Wiener

Department of Management Science

University of Miami

180
181

Participants in Technology in Commercial Aviation Safety Workshop

July 1, 1987

John Enders, Workshop Chairman

Flight Safety Foundation, Inc.

Elizabeth E. Bailey

Graduate School of Industrial Administration

Carnegie-Mellon University

Melvin C. Beard

Office of Airworthiness

Federal Aviation Administration

Robert E. Brown

Radar Engineering Division

Federal Aviation Administration

Steven J. Brown

Aviation Policy

Aircraft Owners and Pilots Association

Robert Cooke

National Business Aircraft Association

Robert A. Davis

747 Division

Boeing Commercial Airplane Co.

B. John Garrick

Pickard, Lowe, and Garrick

Paul Gralnick

Bendix-King Air Transport Avionics Division

Kevin Hilliard

Product Liability Claims

Associated Aviation Underwriters

Cornish F. Hitchcock

Public Citizen Litigation Group

William C. Keil

Engineering and Quality Assurance

USAir, Inc.

Clyde Kizer

Maintenance and Operations Division

United Airlines

H. Knickerbocker

Flight Operations

Douglas Aircraft Co.

William Laynor

Bureau of Technology

National Transportation Safety Board

John McCarthy

Research Applications Program

National Center for Atmospheric Research

Louis M. McNair

Air Line Pilots Association

David C. Nagel

Aerospace Human Factors Research Division

National Aeronautics and Space Administration

Andrew Pickens

Aeronautical Radio, Inc.

John Riley

Sperry Commercial Flight Systems Group

Honeywell, Inc.

Charles H. Sprinkle

National Oceanic and Atmospheric

Administration

National Weather Service

Alan Stephen

Scenic Airlines

Joseph W. Stickle

Low-Speed Aerodynamics Division

National Aeronautics and Space Administration

Fred D. Womack

Flight Operations and Flight Safety

Piedmont Airlines
182

Participants in Aviation Safety Review Meetings

September 22, 1987 and February 24, 1988

Charles Curtis, Chairman

Partner

Van Ness, Feldman, Sutcliffe, & Curtis

Mark Berman Clyde Kizer

Committee on Transportation, Commerce, and Vice President, Technical Services

Communication “ Maintenance and

National Governors’ Association United Airlines

Robert A. Davis Lillian Liburdi

Chief Project Engineer Director

747 Division Management and

Boeing Commercial Airplane Co.

John Enders

President

Flight Safety Foundation, Inc.

Roger Fleming

Vice President

Air Transport Association of America

John Fredericksen

Executive Vice President

Regional Airline Association

John B. Galipault

President

Aviation Safety Institute

Richard Judy

Director

Miami International Airport

Operations Division

Budget Department

Port Authority of New York and New Jersey

Louis M. McNair

Executive Central Air Safety Chairman

Air Line Pilots Association

C.O. Miller

President and Principal Consultant

System Safety, Inc.

John O’Brien

Director, Engineering and Air Safety

Department

Air Line Pilots Association

Richard C. Schwing

Senior Staff Research Engineer

General Motors Research Laboratories

Robert Warner

Executive Vice President

National Association of State Aviation Officials
183

Richard I. Adams,

Air Wisconsin

Alaska Airlines

American Airlines

Aspen Airways

Reviewers and

Federal Aviation Administration

Frank H. Austin, Jr., National Aeronautics and

Space Administration

Bar Harbor Airlines

Wayne J. Barlow, Federal Aviation Administration

Joan W. Bauerlein, Federal Aviation Administration

Charles Billings, National Aeronautics and Space

Administration

Neal A. Blake, Federal Aviation Administration

Boeing Commercial Airplane Co.

Anthony J. Broderick, Federal Aviation

Administration

Cynthia Burbank, Department of Transportation

Robin A. Caldwell, Research and Special Programs

Administration

Walter S. Coleman, Air Transport Association

Richard L. Collie, Regional Airline Association

Maurice F. Connor, Federal Manager’s Association

Delta Airlines

Douglas Aircraft Co.

Eastern Air Lines

William Edmunds, Air Line Pilots Association

John J. Fearnsides, MITRE Corp.

Flying Tigers

Edward T. Harris, Federal Aviation Administration

Edwin S. Harris, Federal Aviation Administration

Hawaiian Airlines

Jayetta Z. Hecker, General Accounting Office

William R. Hendricks, Federal Aviation

Administration

Henson Airlines

John M. Howard, Federal Aviation Administration

Charles H. Huettner, Federal Aviation

Administration

Contributors

Howard E. Johannssen, Professional Airways Systems

Specialists

John S. Kern, Federal Aviation Administration

Linda Little, Virginia Polytechnic institute

Robert E. Machol, Federal Aviation Administration

Homer C. McClure, Federal Aviation

Administration

Dale E. McDaniel, Federal Aviation Administration

Metro Airlines

Midway Airlines

Frank Monastero, T.M. Monitor Corp.

Northwest Airlines

John O’Brien, Air Line Pilots Association

Marvin Olson, Federal Aviation Administration

Clinton V. Oster, Indiana University

Pan American World Airways

Piedmont Airlines

Siegbert Poritzky, Airport Operators Council

international

B. Keith Potts, Federal Aviation Administration

Arnold E. Price, BDM Corp.

William Reynard, National Aeronautics and Space

Administration

Harvey B. Safeer, Federal Aviation Administration

Len Samuels, Federal Aviation Administration

J. Stan Smith, National Transportation Safety Board

Suburban Airlines

Barry M. Sweedler, National Transportation Safety

Board

Patricia Szrom, Department of Transportation

Trans World Airlines

Arthur E. Treiber, MITRE Corp.

United Airlines

USAir

Richard F. Walsh, Department of Transportation

Clifford M. Winston, Brookings [institution

IThls hst Includes Federal A\,latlon Admimstration office directors and super~lsors; many others In the agency also pro~,lded information
Related OTA Reports

●

●

●

●

●

●

●

●

Review of the FAA 1982 National Airspace System Plan.

OTA-STI-176, August 1982, 80 pages.

NTIS order #PB 83-102772.

Airport and Air Traffic Control System.

OTA-STI-175, January 1982, 150 pages.

NTIS order #PB 82-207606.

Impact of Advanced Air Transport Technology: Advanced High-Speed Aircraft.

OTA-T-1 12, April 1980, 115 pages.

NTIS order #PB 80-200504.

Impact of Advanced Air Transport Technology: Air Cargo.

OTA-BP-T-1O, January 1982, 60 pages.

NTIS order #PB 82-186818.

Impact of Advanced Air Transport Technology: Air Service to Small Communities.

OTA-T- 170, February 1982, 54 pages.

NTIS order #PB 82-186800.

Impact of Advanced Air Transport Technology: Financing and Program Alternatives for Advanced

High-Speed Aircraft.

OTA-BT-T-14, August 1982, 56 pages.

NTIS order #PB 83-110585.

U.S. Passenger Rail Technologies.

OTA-STI-222, December 1983, 130 pages.

GPO stock #052-003-00938-2, NTIS order # 84-182 609/AS.

Airport System Development.

OTA-STI-231, August 1984, 270 pages.

GPO stock #052-003-00960-9, NTIS order #85-127 793/AS.

NOTE: Reports are available through the U.S. Government Printing Office, Superintendent of Documents, Washington, DC 20401-9325, (202)

783-3238; and/or the National Technical Information Service, 5285 Port Royal Road, Springfield, VA 22161-0001, (703) 487-4650.