United States General Accounting Office

GAO Report to Congressional Requesters

September 1998 NATIONAL AIRSPACE

SYSTEM

FAA Has Implemented

Some Free Flight

Initiatives, but

Challenges Remain

GAO/RCED-98-246

GAO United States

General Accounting Office

Washington, D.C. 20548

Resources, Community, and

Economic Development Division

B-279201 

September 28, 1998

The Honorable John McCain

Chairman

The Honorable Ernest F. Hollings

Ranking Minority Member

Committee on Commerce, Science, and

 Transportation

United States Senate

The Honorable Slade Gorton

Chairman

The Honorable Wendell H. Ford

Ranking Minority Member

Subcommittee on Aviation

Committee on Commerce, Science, and

 Transportation

United States Senate

In response to your request, this report discusses the results of our review

of (1) the status of the Federal Aviation Administration’s (FAA) efforts to

implement free flight, including a planned operational demonstration

formerly known as Flight 2000 and now called the Free Flight Operational

Enhancement Program, and (2) the views of the aviation community and

FAA on the challenges that must be met to implement free flight in a

cost-effective manner.

We are providing copies of this report to interested congressional

committees and subcommittees, the Secretary of Transportation, the

Administrator of the Federal Aviation Administration, and other interested

parties. Copies will also be made available to others upon request. Please

call me at (202) 512-3650 if you have any questions about the report. Major

contributors to this report are listed in appendix V.

Gerald L. Dillingham, Ph.D.

Associate Director, Transportation Issues

Page 1 GAO/RCED-98-246 Free Flight Initiatives
Executive Summary

Purpose The predicted growth in air traffic and the aging of air traffic control

equipment led the Federal Aviation Administration (FAA) to undertake a

multibillion-dollar modernization effort in 1981 to improve the safety,

capacity, and efficiency of the nation’s air traffic control system. Since that

time, this program has experienced substantial cost overruns, lengthy

schedule delays, and significant performance shortfalls. To get the

modernization effort back on track and thereby address the limitations of

the present system and satisfy users’ growing demands, FAA—in

consultation with the aviation community—is developing a phased

approach to modernization, including a new way of managing air traffic

known as “free flight.” Under the modernization program, FAA plans to

introduce a host of new technologies and procedures that will enable free

flight—allowing the agency to move gradually from its present use of

highly structured rules and procedures for air traffic operations to a more

flexible system in which decisions for conducting flight operations will be

based increasingly on collaboration between FAA and users. For example,

these technologies and associated procedures will give pilots and

controllers more precise information about the location of aircraft and

allow them to exchange information more efficiently. With more precise

and efficiently exchanged information, pilots will have more flexibility to

change their route, speed, and altitude (under certain conditions) with

fewer restrictions, thus saving users time and money and allowing FAA to

improve the air traffic control system’s safety and use airspace and airport

resources more efficiently.

Because FAA is at a critical juncture in its plans to implement this new

system of air traffic management, the Senate Committee on Commerce,

Science, and Transportation and its Subcommittee on Aviation asked GAO

to monitor the progress of free flight initiatives and provide them with a

series of reports. This first report discusses (1) the status of FAA’s efforts

to implement free flight, including a planned operational demonstration

known as Flight 2000,1

 and (2) the views of the aviation community and

FAA on the challenges that must be met to implement free flight

cost-effectively.

Background FAA’s mission is to promote the safe, orderly, and expeditious flow of air

traffic in the U.S. airspace system, commonly referred to as the National

Airspace System (NAS). To accomplish its mission, FAA provides air traffic

1

FAA officials working with the aviation community reached broad consensus on a general roadmap

for restructuring the Flight 2000 program—including a recommendation that it be renamed the “Free

Flight Operational Enhancement Program”—and presented this roadmap to FAA for formal approval

in Sept. 1998.

Page 2 GAO/RCED-98-246 Free Flight Initiatives
Executive Summary

services 24 hours a day, 365 days a year. The air traffic control system,

which is the principal component of the NAS, comprises a vast network of

radars; automated data processing, navigation, and communications

equipment; and air traffic control facilities. Through the air traffic control

system, FAA, among other things, controls takeoffs and landings and

manages the flow of traffic between airports. Other components of the NAS

include airports or landing areas; aeronautical charts, information, and

services; rules, regulations, and procedures; technical information; and

personnel and material.

Over the past 17 years, FAA has had an ongoing program to modernize the

air traffic control system. Under this program, FAA is upgrading and

replacing equipment and facilities and developing new technologies to

help improve the safety, efficiency, and capacity of the system. However,

this program has substantially exceeded its budget, encountered lengthy

delays, and fallen short in its performance. As a result, the aviation

community’s confidence in FAA’s ability to manage the modernization

program has been weakened. While many of FAA’s efforts under the

modernization program, such as replacing controllers’ workstations and

supporting equipment, are not a part of the free flight initiatives, these

efforts will provide the infrastructure that is critical for its

implementation. To address the shortcomings in its modernization

program and develop consensus on and commitment to the agency’s

future approach to both modernization and free flight, FAA has been

working with the aviation system’s users and their major trade

organizations, representatives of air traffic control personnel, equipment

manufacturers, the Department of Defense (DOD), and others (collectively

referred to as stakeholders).

Free flight is a new system of air traffic management that will provide

controllers and pilots with new technologies and procedures that will

allow them to increase the safety, capacity, and efficiency of air traffic

operations throughout the NAS. The implementation of free flight is

expected to affect a wide range of users—from part-time pilots to major

airlines—and allow many of them to take advantage of increased

operating flexibilities. Despite the availability of such flexibilities to pilots,

controllers will retain the ultimate decision-making authority for air traffic

operations.

Page 3 GAO/RCED-98-246 Free Flight Initiatives
Executive Summary

Results in Brief Since 1994, FAA officials and stakeholders, under the leadership of RTCA,

have been collaborating to implement free flight.2

 These early efforts led to

a definition of free flight, a set of recommendations—most of which

contain implementing initiatives—and an action plan to gradually move

toward a more flexible operating system. While working to implement the

recommendations, FAA and stakeholders agreed on the need to focus their

efforts on deploying technologies that will provide early benefits to users.

In early 1998, FAA and stakeholders developed a strategy that calls for the

phased implementation of free flight, beginning with Free Flight Phase 1.

Under this first phase, FAA and stakeholders have agreed upon the core

technologies that are expected to provide these early benefits, as well as

the locations where they will be deployed. However, until recently, FAA

and many stakeholders have not agreed on how best to conduct a limited

operational demonstration of free-flight-related technologies and

procedures—known as the Flight 2000 program.3 FAA is currently

prohibited from spending any fiscal year 1998 funds on the Flight 2000

demonstration itself. Congressional conferees for the Department of

Transportation’s fiscal year 1998 appropriations act stated that additional

financial and technical planning were needed before the demonstration

program would be funded. Stakeholders concurred that FAA had yet to

develop a detailed plan for conducting this demonstration. While they

generally agreed with the need for such a demonstration, they have

questioned whether the lessons learned from FAA’s recommended

demonstration, to be conducted primarily in Alaska and Hawaii, would be

transferable to operations in the continental United States, where free

flight operations will ultimately focus. To address the concerns of

stakeholders, FAA has been working with them—under the leadership of

RTCA—to restructure the Flight 2000 demonstration. FAA and stakeholders

agreed on a general roadmap for the demonstration, including a

recommendation that the demonstration be renamed the “Free Flight

Operational Enhancement Program,” and presented it to FAA for approval

in September 1998.

Despite these efforts, FAA and stakeholders have identified numerous

challenges that will need to be met if free flight—including Free Flight

2

RTCA serves in an advisory capacity to FAA, making recommendations that are subject to approval by

FAA. It was organized as the Radio Technical Commission for Aeronautics in 1935 to provide a forum

where industry and government representatives could discuss aviation issues and develop

consensus-based recommendations. In Nov. 1991, it reorganized and shortened its name to RTCA.

3

Flight 2000 (now the Free Flight Operational Enhancement Program) is intended as a risk-mitigation

demonstration of communication, navigation, and surveillance technologies planned for use under

future phases of free flight.

Page 4 GAO/RCED-98-246 Free Flight Initiatives
Executive Summary

Phase 1 and Flight 2000 (now the Free Flight Operational Enhancement

Program)—is to be implemented cost-effectively:

• Stakeholders told GAO that FAA will need to provide effective leadership

and management of the modernization efforts both within and outside the

agency.

• Stakeholders cited the need for FAA—in collaboration with them—to

further develop its plans for implementing free flight, including

establishing clear goals for what it intends to achieve and developing

measures for tracking the progress of modernization and free flight.

• FAA and stakeholders agreed on the need to address outstanding issues

related to technology development and deployment, such as improving the

agency’s process for determining that new equipment is safe for its

intended use and addressing the impact of modernization on human

operators, including controllers, maintenance staff, and pilots.

• FAA and stakeholders also identified a range of other challenges that will

need the agency’s attention, including coordinating FAA’s modernization

and free flight efforts with those of the international community and

integrating the various technologies that will be used under free flight

operations with one another as well as into the air traffic control system.

Principal Findings

Status of Free Flight

Implementation Efforts

In 1995, FAA and stakeholders defined free flight and outlined 44

recommendations—many of which have multiple initiatives—for

consideration in implementing free flight.4

 In 1996, they developed an

action plan with time frames to guide the implementation of these

recommendations. Since that time, they have fully implemented 1 of 35

recommendations scheduled for completion by the end of 1997 and have

made substantial progress toward completing initiatives under many of

these and the remaining recommendations.5

 Under the fully implemented

recommendation, FAA has incorporated airline schedule updates (e.g.,

airline delays and cancellations) into its Traffic Flow Management system

to allow the agency to work more effectively with the airlines to reduce

unnecessary operating restrictions and delays. In addition, under a

4

The 44 recommendations were developed by FAA and stakeholders under RTCA Free Flight Task

Force 3. This task force was conducted under the leadership of RTCA, a nonprofit organization that

serves as an advisor to FAA.

5

The remaining nine recommendations are scheduled to be implemented between 1998 and

2001/beyond.

Page 5 GAO/RCED-98-246 Free Flight Initiatives
Executive Summary

recommendation to extend the benefits of data exchange, FAA has

deployed digital displays of departure information in lieu of voice

messages for pilots’ use at 57 sites, as planned, and is currently working to

expand the digital exchange of information about weather, airport, and

facility conditions. Digital communications provide an advantage over

voice communications by helping to relieve congested voice frequencies

and reduce the number of operational errors that are caused directly or

indirectly by miscommunication. Under another recommendation, FAA and

stakeholders are working under the leadership of RTCA to improve the

process that the agency uses to ensure that new technologies are safe for

their intended use. Furthermore, as part of another recommendation, FAA

has deployed technology—on a limited basis—to improve the sequencing

of airplanes as they enter, depart, and operate within terminal airspace.

In addition to implementing the recommendations and their initiatives, FAA

began to allow users to choose routes and use procedures (under certain

conditions) that could save them time and money through two ongoing

programs—the National Route Program and the Future Air Navigation

System. In 1990, FAA launched the National Route Program to give users

the flexibility to select and fly more direct routes. FAA estimates that the

aviation industry saves over $40 million annually through participation in

this program. Under the Future Air Navigation System program, which is

conducted primarily over the oceans, new technology is used to improve

the efficiency of communications between pilots and controllers. This

technology, in combination with new procedures, is expected to provide

them with more precise information on the location of aircraft so that

distances between aircraft can be safely reduced—enabling users to save

time and money. However, stakeholders told GAO that because FAA has not

deployed the promised hardware and software infrastructure to support

the use of these new technologies, the benefits to users have been

marginal.

FAA’s collaborative efforts with the aviation community to develop plans

for implementing free flight have led to a general consensus on an

incremental approach—beginning with Free Flight Phase 1—that would

cost less for FAA and extend early benefits to users. This first phase is

expected to provide these early benefits through the limited deployment of

technologies that are intended to enhance the system’s safety, capacity,

and efficiency. For example, these technologies are expected to provide

controllers with better information to detect and resolve potential

conflicts between aircraft and to sequence traffic more efficiently. With

such information, controllers will be able to give pilots increased

Page 6 GAO/RCED-98-246 Free Flight Initiatives
Executive Summary

flexibility to fly more optimal routes but will retain the ultimate authority

for decision-making. FAA expects to implement Free Flight Phase 1 by 2002

and is currently developing a plan that will provide more details on

implementing the program.

FAA and many stakeholders have disagreed on how best to implement

Flight 2000—a limited operational demonstration of new technologies and

procedures that was to be used under free flight to improve

communication, navigation, and surveillance capabilities. Initially, FAA

announced this initiative without consulting users, and disagreements

persisted until recently, despite FAA’s ongoing efforts to resolve them

collaboratively. FAA believed that the Flight 2000 demonstration, as

planned primarily for Alaska and Hawaii, was a means to mitigate the risks

associated with implementing free flight. While many stakeholders agree

with the need to mitigate risks, they have had strong reservations about

conducting this demonstration in these remote locations, believing that

the lessons learned there will not transfer well to operations in the

continental United States. To address these concerns, FAA and

stakeholders—working under the leadership of RTCA—developed a

roadmap for restructuring Flight 2000 and presented it to FAA in

September 1998. Among other things, this roadmap recommended that

(1) the program be conducted in the Ohio Valley and Alaska, (2) nine

major operational capabilities be implemented, and (3) the demonstration

be renamed the “Free Flight Operational Enhancement Program.” In

developing this roadmap, both FAA and stakeholders emphasized the

critical role of safety in achieving operational efficiencies, and many

components of the program are designed to enhance safety. FAA is

currently considering RTCA’s roadmap. While FAA had planned to begin the

Flight 2000 demonstration by 2000, time frames for the new demonstration

are uncertain because issues such as funding and the need for additional

planning have not been resolved.

Challenges to

Implementing Free Flight

Successfully

FAA and stakeholders generally agree on the phased approach to

implementing free flight but have identified several challenges that must

be addressed if free flight is to be implemented cost-effectively.

Page 7 GAO/RCED-98-246 Free Flight Initiatives
Executive Summary

Effective Management Is the

Key to Successful

Implementation

Some stakeholders and FAA officials believe that strong FAA leadership is

needed both within and outside the agency to successfully implement free

flight. In particular, they maintain that FAA needs to encourage more

effective communication and coordination among its various program

offices responsible for modernization. According to some stakeholders

and FAA officials, despite the agency’s move to use integrated

cross-program teams to improve coordination, this effort has fallen short

because some participants are more beholden to their individual program

offices than they are to the goals of the team. FAA has begun to develop

incentives to encourage staff to work more cooperatively. As for FAA’s

leadership within the aviation community, some stakeholders cited the

need for FAA to make and stick to its decisions so that they can move

forward with their plans for free flight. While stakeholders recognize that

FAA must balance competing priorities, they find it frustrating when the

agency announces a course of action and then either drops the effort or

moves in a different direction. Some stakeholders told GAO that this

indecision has eroded their confidence in FAA’s ability to lead

modernization efforts, including free flight. Effective leadership will also

be critical to successfully implement the planned evolutionary approach to

developing and deploying technology and to demonstrate that FAA can

effectively manage its air traffic control modernization programs and

deliver promised capabilities.

Clear Goals and Measures and

Sufficiently Detailed Plans Are

Needed

To move safely and efficiently from the present system to free flight,

stakeholders said that FAA needs to develop specific goals for what it

intends to achieve and a system for measuring its progress. For example,

one stakeholder cautioned that if FAA does not fully consider what the

system needs to look like 10 to 20 years from now, it runs the risk of

investing in technologies that may not address the system’s future needs.

In addition, some stakeholders and FAA officials agree on the need to

develop baseline data for use in tracking their progress in improving the

system’s safety, capacity, and efficiency. As a next step, stakeholders

maintain that the transition to free flight will require FAA to develop

detailed plans for the various activities under free flight, including Free

Flight Phase 1, Flight 2000 (now the Free Flight Operational Enhancement

Program), and various follow-on efforts. Stakeholders told GAO that these

plans need to include cost/benefit analyses to provide them with

assurances that their investments in free flight technologies will result in

benefits to quickly offset expenses. They also said that new procedures are

critical to allowing them to fully exploit these benefits and expressed

concern that such procedures will not be developed and implemented in a

timely fashion.

Page 8 GAO/RCED-98-246 Free Flight Initiatives
Executive Summary

Issues Related to

Technology Development

and Deployment Remain to

Be Resolved

FAA and stakeholders recognize that certain issues related to the

development and deployment of free flight technology need to be resolved.

Chief among these issues is the need for FAA to streamline its process for

determining that new equipment is safe for its intended use. However,

several stakeholders cautioned that FAA will need to take care to ensure

that changes to the process do not inadvertently compromise safety. FAA

and the aviation community are currently working together to identify

possible solutions. Many stakeholders also noted that successfully

implementing free flight is inextricably linked to identifying and

addressing issues associated with human factors. These issues include

developing a reasonably paced training schedule to help ensure that pilots,

controllers, and maintenance staff are not overburdened by too many

changes at one time, as well as identifying risks associated with changes in

technologies and procedures and the potential effects of these changes on

human operations in a free flight environment.

Other Outstanding Issues

May Limit the

Effectiveness of Free

Flight Implementation

FAA and stakeholders identified other challenges that must be met for free

flight to be successfully implemented. For example, airlines that operate

internationally and DOD believe that FAA needs to work diligently to ensure

that, to the extent possible, users do not have to purchase multiple sets of

equipment to meet different operating requirements in various parts of the

world. While FAA is currently working with its international counterparts

on various issues related to modernization—including issues related to

free flight—some stakeholders question the sufficiency of the agency’s

efforts to coordinate technology selection decisions that will allow users

to operate worldwide.

Some stakeholders and FAA officials cited the need for FAA to ensure that,

to the extent possible, technologies will work together to maximize

potential benefits. For example, FAA has new technologies that are

expected to improve the efficiency of operations at high altitudes, close to

the terminal, and on the ground. Because some of these technologies have

not been designed to work together, some stakeholders and FAA officials

contend that their potential benefits—e.g., allowing distances between

aircraft to be safely reduced, when practical, throughout a flight’s

operation—will not be maximized unless the technologies are integrated.

The agency recognizes that it does not have the internal expertise or

experience to integrate the hardware and software that will be on board

participating aircraft as part of the Flight 2000 demonstration (now the

Free Flight Operational Enhancement Program) and plans to hire an

integration contractor to do this work. Finally, stakeholders also stressed

Page 9 GAO/RCED-98-246 Free Flight Initiatives
Executive Summary

that the benefits of free flight depend on having adequate airport surface

capacity (such as runways and gates) and question whether FAA is paying

enough attention to the system’s lack of such capacity. They noted that if

users get to their destination more quickly, only to be delayed by limited

airport capacity, they will lose some or all of the expected benefits.

Agency Comments GAO provided copies of a draft of this report to FAA for its review and

comment. GAO met with FAA officials, including the Director, Program

Office, Free Flight Phase 1, and the Acting Program Directors for Flight

2000 and Architecture and Systems Engineering, who generally agreed

with the contents of the report and provided clarifying comments that

have been incorporated as appropriate.

Page 10 GAO/RCED-98-246 Free Flight Initiatives
Page 11 GAO/RCED-98-246 Free Flight Initiatives
Contents

Letter 1

Executive Summary 2

Chapter 1 

Implementation of

Free Flight

Represents a Shift

From Air Traffic

Control to

Collaborative Air

Traffic Management

16

National Airspace System/Air Traffic Control System 17

What Is Free Flight? 20

Objectives, Scope, and Methodology 22

Chapter 2 

FAA’s Efforts to

Implement Free Flight

24

Progress Toward Implementing Free Flight Recommendations 24

Existing Programs Extend Some Flexibility to Users 26

FAA’s Efforts to Reach Consensus Lead to Free Flight Phase 1 27

Plans for Free Flight Demonstration Still Under Development 30

Chapter 3 

FAA and the Aviation

Community Face

Many Challenges in

Implementing Free

Flight Cost-Effectively

32

Effective Management Is the Key to Implementing Free Flight

Successfully

32

Clear Goals and Measures and Sufficiently Detailed Plans Are

Necessary for Implementing Free Flight

35

FAA Needs to Address Outstanding Issues Related to Technology

Development and Deployment

41

Other Outstanding Issues May Limit Effectiveness of Free Flight’s

Implementation

46

Appendixes Appendix I: RTCA’s Free Flight Recommendations 50

Appendix II: Status of Selected RTCA Recommendations Related

to Free Flight Phase 1, as of July 1998

56

Appendix III: Proposed Operational Capabilities for Flight 2000,

Renamed the Free Flight Operational Enhancement Program

72

Appendix IV: Expert Advisors on Free Flight 75

Appendix V: Major Contributors to This Report 76

Page 12 GAO/RCED-98-246 Free Flight Initiatives
Contents

Figures Figure 1.1: Summary of Air Traffic Control Over the Continental

United States and Oceans

19

Figure 2.1: Proposed Locations for Deploying and Testing Free

Flight Phase 1 Technologies

29

Abbreviations

ADS Automatic Dependent Surveillance

ADS-B Automatic Dependent Surveillance-Broadcast

ARINC Aeronautical Radio Incorporated

ARTCC Air Route Traffic Control Center

ATC air traffic control

ATIS Automatic Terminal Information Service

ATM Air Traffic Management

CDM Collaborative Decision Making

CPDLC Controller Pilot Data Link Communications

CTAS Center TRACON Automation System

DOD Department of Defense

DSR Display System Replacement

DSS decision support system

FAA Federal Aviation Administration

FANS Future Air Navigation System

FAST Final Approach Spacing Tool

FIS Flight Information Service

GAO General Accounting Office

GPS Global Positioning System

HF High Frequency

LAAS Local Area Augmentation System

MDCRS Meteorological Data Collection and Reporting System

MIT Massachusetts Institute of Technology

NAS National Airspace System

NRP National Route Program

PDC Pre-Departure Clearance

pFAST passive Final Approach Spacing Tool

R&D research and development

RNAV Random Navigation/Area Navigation

RVSM Required Vertical Separation Minimum

SATCOM Satellite Voice and Data Communications

SMA Surface Movement Advisor

STARS Standard Terminal Automation Replacement System

SUA Special Use Airspace

TFM Traffic Flow Management

TFM-ART Traffic Flow Management-Architecture and Requirements

Team

Page 13 GAO/RCED-98-246 Free Flight Initiatives
Contents

TIS Traffic Information Service

TIS-B Traffic Information Service-Broadcast

TMA Traffic Management Advisor

TRACON Terminal Radar Approach Control

URET User Request Evaluation Tool

WAAS Wide Area Augmentation System

Page 14 GAO/RCED-98-246 Free Flight Initiatives
Page 15 GAO/RCED-98-246 Free Flight Initiatives
Chapter 1 

Implementation of Free Flight Represents a

Shift From Air Traffic Control to

Collaborative Air Traffic Management

The Federal Aviation Administration’s (FAA) mission is to promote the

safe, efficient, and expeditious flow of air traffic in the U.S. airspace

system, commonly referred to as the National Airspace System (NAS). To

accomplish its mission, FAA provides services 24 hours a day, 365 days a

year, through its air traffic control (ATC) system—the principal component

of the NAS.

6

 Predicted growth in air traffic and aging equipment led FAA to

initiate a multibillion-dollar modernization effort in 1981 to increase the

safety, capacity, and efficiency of the system. However, over the past 17

years, FAA’s modernization program has experienced substantial cost

overruns, lengthy schedule delays, and significant performance shortfalls.

Consequently, many of the benefits anticipated from the modernization

program—new facilities, equipment, and procedures—have not been

realized, and the efficiency of air traffic control operations has been

limited. In addition, the expected growth in air traffic will place added

strains on the system’s capacity.

To get the modernization effort back on track and thereby address the

limitations of the present system and meet the growing demand for

increasing its capacity, FAA—in consultation with the aviation

community—is developing plans to implement a phased approach to

modernization, including a new concept of air traffic management known

as “free flight.” To enable free flight, FAA intends to introduce a host of new

technologies and procedures that will allow the agency to gradually move

from its present system of air traffic control, which relies heavily on rules,

procedures, and tight control over aircraft operations, to a more

collaborative system of air traffic management. Under such a system,

users would have more flexibility to select optimal flight paths, whose use

would lower costs, improve safety, and help accommodate future growth

in air traffic through the more efficient use of airspace and airport

resources. Implementing this new air traffic management system will

require FAA to introduce new technologies7

 and procedures. FAA plans to

6

The ATC system comprises a vast network of radars; automated data processing, navigation, and

communication equipment; and air traffic control facilities. It is through the ATC system that FAA

controls takeoffs and landings and manages the flow of traffic between airports. Other components of

the NAS include airports or landing areas; aeronautical charts, information, and services; rules,

regulations, and procedures; technical information; and personnel and material.

7

Many of these technologies, such as the User Request Evaluation Tool (conflict probe) and Single

Center Traffic Management Advisor and Passive Final Approach Spacing Tool (traffic sequencing

tools) are currently in various stages of development.

Page 16 GAO/RCED-98-246 Free Flight Initiatives
Chapter 1 

Implementation of Free Flight Represents a

Shift From Air Traffic Control to

Collaborative Air Traffic Management

test other new technologies and procedures through an initiative called

Flight 2000 (now the Free Flight Operational Enhancement Program).8

National Airspace

System/Air Traffic

Control System

FAA’s air traffic controllers direct aircraft through the NAS. Automated

information-processing and display, communication, navigation,

surveillance, and weather equipment allow air traffic controllers to see the

location of aircraft, aircraft flight plans, and prevailing weather conditions,

as well as to communicate with pilots. FAA controllers are primarily

located in three types of facilities: air traffic control towers, terminal area

facilities, and en route centers. The functions of each type of facility are

described below.

• Airport towers control the flow of aircraft—before landing, on the ground,

and after take-off—within 5 nautical miles of the airport and up to 3,000

feet above the airport. A combination of technological and visual

surveillance is used by air traffic controllers to direct departures and

approaches, as well as to communicate instructions and weather-related

information to pilots.

• Terminal area facilities—known as Terminal Radar Approach Control

(TRACON) facilities—sequence and separate aircraft as they approach and

leave busy airports, beginning about 5 nautical miles and extending to

about 50 nautical miles from the airport and up to 10,000 feet above the

ground.

• Air Route Traffic Control Centers (ARTCC)—or en route centers—control

planes in transit over the continental United States and during approaches

to some airports. Planes are controlled through regions of airspace by en

route centers responsible for the regions. Control is passed from one en

route center to another as a plane moves across a region until it reaches

TRACON airspace. Most of the en route centers’ controlled airspace extends

above 18,000 feet for commercial aircraft. En route centers also handle

lower altitudes when dealing directly with a tower or after agreeing with a

terminal facility. Aircraft over the ocean are handled by en route centers in

Oakland and New York. Beyond the radars’ sight, controllers must rely on

periodic radio communications through a third party—Aeronautical Radio

Incorporated (ARINC), a private organization funded by the airlines and FAA

to operate radio stations—to determine aircraft locations.

8

Among other capabilities, this demonstration will use (1) the Flight Information Service to provide

enhanced weather information and the status of Special Use Airspace, (2) Automatic Dependent

Surveillance-Broadcast in a number of ways to improve the efficiency of ground and air operations,

and (3) the Traffic Information Service to improve pilots’ awareness of surrounding traffic and the

efficiency of operations in low-visibility conditions.

Page 17 GAO/RCED-98-246 Free Flight Initiatives
Chapter 1 

Implementation of Free Flight Represents a

Shift From Air Traffic Control to

Collaborative Air Traffic Management

• Flight Service Stations provide weather and flight plan services, primarily

for general aviation pilots.9

See figure 1.1 for a visual summary of air traffic control over the

continental United States and oceans.

9

Our report focuses on free flight technologies that will be implemented primarily in the tower,

terminal, and en route environments. Therefore, we do not include further discussion of Flight Service

Stations.

Page 18 GAO/RCED-98-246 Free Flight Initiatives
Chapter 1 

Implementation of Free Flight Represents a

Shift From Air Traffic Control to

Collaborative Air Traffic Management

Figure 1.1: Summary of Air Traffic Control Over the Continental United States and Oceans

TRACON

ARINC

Oceanic

En Route

Center

En Route

Center

Flight Service

Station

En Route

Center

TRACON

Airport Tower

Airport Tower

Departure Control

Approach Control

Continental

United States

Local and Ground Control

Page 19 GAO/RCED-98-246 Free Flight Initiatives
Chapter 1 

Implementation of Free Flight Represents a

Shift From Air Traffic Control to

Collaborative Air Traffic Management

FAA will continue to operate en route, terminal, and tower facilities under

the new air traffic management system; controllers in these facilities will

be able to manage flight operations more collaboratively through the use

of new decision support tools. For example, two new traffic management

tools will allow en route and terminal controllers to better sequence

aircraft as they move into the terminal environment—potentially

increasing the system’s safety and efficiency.10

What Is Free Flight? Free flight is a new way of managing air traffic that is designed to enhance

the safety, capacity, and efficiency of the NAS. Under this new management

system, air traffic control is expected to move gradually from a highly

structured system based on elaborate rules and procedures to a more

flexible system that allows pilots, within limits, to change their route,

speed, and altitude, notifying the air traffic controller of the new route. In

contrast, under the present system, while flight plans are developed in

conjunction with air traffic control personnel, aircraft are required to fly

along specific routes with minimal deviation. When deviations from

designated routes are allowed—to, for example, avoid severe

weather—they must be pre-approved by an air traffic controller. Under

free flight, despite the availability of flexibilities to pilots, the ultimate

decision-making authority for air traffic operations will continue to reside

with controllers.

While FAA and the aviation community have recently increased their efforts

to implement free flight, the concept of free flight—allowing pilots to fly

more optimal routes—is not new. In fact, the idea has been around for

decades. With the development of navigation technology in the 1970s that

allowed aircraft to fly directly from origin to destination without following

fixed air routes (highways in the sky), the possibility of providing pilots

with flexibility in choosing routes became viable. However, until recently,

movement to develop the procedures and decision support systems

needed to fully use this type of point-to-point navigation has been slow. In

the last several years, because of the need to meet demands for increasing

the system’s capacity and efficiency, FAA and aviation system users and

their major trade organizations, representatives of air traffic control

personnel, equipment manufacturers, the Department of Defense (DOD),

10Under Free Flight Phase 1, FAA will use two Center TRACON Automation System (CTAS) tools:

Traffic Management Advisor (TMA) and Final Approach Spacing Tool (FAST). TMA will provide en

route/terminal controllers with automation tools to schedule aircraft to enter or depart from airspace

that is between 5 and 50 miles from the airport. FAST will provide runway assignment and sequence

numbers to air traffic controllers. FAST operates in conjunction with TMA to provide integrated traffic

management system decision support tools. En route and terminal traffic management coordinators

will use TMA, and terminal radar controllers will use FAST.

Page 20 GAO/RCED-98-246 Free Flight Initiatives
Chapter 1 

Implementation of Free Flight Represents a

Shift From Air Traffic Control to

Collaborative Air Traffic Management

and others (collectively referred to as stakeholders) have been working on

plans to accelerate the implementation of free flight.

To enable this new system of air traffic management, FAA plans to

introduce a range of new technologies and procedures that will give pilots

and controllers more precise information about the location of aircraft.

This information will eventually allow for the distances between aircraft to

be safely reduced—in turn, allowing more aircraft to operate in the

system. For example, a new tool planned for use primarily in the en route

environment will give controllers better information about the location of

aircraft so that they can detect and resolve potential conflicts sooner than

they can using current technology. Similarly, pilots will have more precise

information about the location of their aircraft in relation to other aircraft.

The use of these technologies will help to improve the system’s safety and

capacity. While free flight will provide pilots with more flexibility,

different situations will dictate its use. For instance, in clear, uncrowded

skies, pilots may be able to use free flight fully, but some restrictions may

be necessary during bad weather or in highly congested areas.

FAA Developed a

Definition of Free Flight

With Stakeholders

Developing an integrated, modernized air traffic control system requires

that government and stakeholders reach consensus on or hold

complementary views of what they want to achieve and how they want to

achieve it. In an effort to gain consensus, in 1994, FAA asked RTCA to form a

select committee of government and industry participants to study free

flight. This group included representatives from general aviation, the

airline industry, pilots’ and air traffic controllers’ unions, and government.

To continue the work of this select committee, RTCA formed a task force

with similar representation to develop a strategy for implementing free

flight. As part of its work, the task force defined free flight as

“a safe and efficient flight operating capability under instrument flight rules in which the

operators have the freedom to select their path and speed in real time. Air traffic

restrictions are only imposed to ensure separation, to preclude exceeding airport capacity,

to prevent unauthorized flight through Special Use Airspace (SUA),11 and to ensure safety of

flight. Restrictions are limited in extent and duration to correct the identified problem. Any

activity which removes restrictions represents a move toward Free Flight.”

Stakeholders generally agree with the above broad concept—especially

the idea that any activity that removes restrictions represents a move

11In general, SUA is airspace designated for use by DOD and other federal agencies to carry out special

research, testing, training, and other activities. Nonparticipating aircraft—both civil and military—may

be restricted from flying into such areas.

Page 21 GAO/RCED-98-246 Free Flight Initiatives
Chapter 1 

Implementation of Free Flight Represents a

Shift From Air Traffic Control to

Collaborative Air Traffic Management

toward free flight. However, because users have different priorities based

on their use of the system, they have different ideas about how best to

implement this concept.

Free Flight Will Affect a

Wide Range of Users in All

Operating Environments

RTCA has found that the implementation of free flight will affect a wide

range of users—from part-time pilots to major airlines—depending on the

operating environment. For example, in the en route environment, users

will be allowed to fly more optimal routes between airports, thus saving

time and money. In addition, under certain conditions, these users may be

allowed to safely reduce the distance between themselves and other

aircraft. Similarly, in airspace between 5 and 50 miles from the airport, the

improved sequencing of traffic for approaches and landings will provide

the potential for users to operate more efficiently than under the present

system. Improved sequencing is expected to increase the number of

aircraft that can safely operate in this environment at a given time. In

addition, improved information sharing between pilots and controllers on

the location of aircraft on an airport’s surface, for example, is expected to

allow for better use of the airport’s surface capacity (such as runways and

gates). Efficient use of this limited capacity is key to allowing users to

maximize the benefits of operations under free flight.

Objectives, Scope,

and Methodology

In light of FAA’s current efforts to replace its aging infrastructure and keep

pace with increasing demands for air traffic services through the new

system of air traffic management known as free flight, the chairmen and

ranking minority members of the Senate Committee on Commerce,

Science, and Transportation and its Subcommittee on Aviation asked us to

monitor the implementation of FAA’s efforts and provide them with a series

of reports. This initial report provides (1) an overview of FAA’s progress to

date in implementing free flight, including Flight 2000 (now the Free Flight

Operational Enhancement Program), and (2) the views of the aviation

community and FAA on the challenges that must be met to implement free

flight cost-effectively.

To address the first objective, we met with key FAA officials responsible for

the programs involved in the agency’s free flight implementation efforts to

gain a better understanding of how FAA is coordinating the agencywide and

program-specific elements of free flight. The issues discussed with these

officials included (1) the definition/philosophy of free flight; (2) details on

key agencywide and program-specific initiatives, such as Flight 2000 (now

the Free Flight Operational Enhancement Program); and (3) the status of

Page 22 GAO/RCED-98-246 Free Flight Initiatives
Chapter 1 

Implementation of Free Flight Represents a

Shift From Air Traffic Control to

Collaborative Air Traffic Management

the agency’s efforts to develop, deploy, and integrate new technologies;

mitigate risk; develop metrics; collaborate with other FAA program offices

and stakeholders; improve certification procedures; develop cost/benefit

analyses; and gain buy-in to free flight implementation efforts among FAA

staff and the aviation community. We discussed these same issues with a

broad range of stakeholders to get their views on the agency’s progress to

date in implementing free flight. These stakeholders, who have

collaborated with FAA to implement free flight, included representatives of

RTCA, trade organizations (such as the Air Transport Association, Airports

Council International, Regional Airline Association, National Business

Aircraft Association, and Aircraft Owners and Pilots Association),

employee unions (including the National Air Traffic Controllers

Association, Air Line Pilots Association, and Professional Airways Systems

Specialists), DOD, academic institutions (Massachusetts Institute of

Technology (MIT) and University of Illinois, Champaign) and research and

contracting organizations (MIT Lincoln Laboratory, Department of

Transportation/Volpe Center, National Aeronautics and Space

Administration, and MITRE), major airlines, cargo carriers, and aircraft

and avionics manufacturers.

In addressing the second objective, we asked the same FAA officials and

stakeholders to identify the key challenges that must be met for free flight

to be implemented cost-effectively.

As part of our review for both objectives, we researched the current

literature and reviewed relevant FAA documents (such as the NAS

architecture and operational concept, capital investment plan, and cost

and schedule information for key projects). In addition, we obtained and

reviewed documentation from stakeholders in support of their positions

on outstanding issues related to implementing free flight.

We provided copies of a draft of this report to FAA for its review and

comment. We met with FAA officials, including the Director, Program

Office, Free Flight Phase 1, and the Acting Program Directors for Flight

2000 and Architecture and Systems Engineering, who generally agreed

with the contents of the report and provided clarifying comments, which

we incorporated as appropriate.

We conducted our audit work from November 1997 through August 1998

in accordance with generally accepted government auditing standards.

Page 23 GAO/RCED-98-246 Free Flight Initiatives
Chapter 2 

FAA’s Efforts to Implement Free Flight

Under its air traffic control modernization program, FAA is upgrading its

facilities and equipment—including replacing aging infrastructure, such as

controllers’ workstations and the Host computer—and ensuring that its

systems comply with Year 2000 requirements.12 While these efforts are not

part of free flight, they will provide the infrastructure that is critical for its

implementation. To define free flight and develop recommendations,

associated initiatives, and time frames for its implementation, FAA has

worked with stakeholders under the leadership of RTCA—a nonprofit

organization that serves as an advisor to FAA. As of July 1998, 1 of 44

recommendations had been completed, and substantial progress has been

made in implementing many of the initiatives that fall under the remaining

recommendations.

While working to implement the 44 recommendations, FAA and

stakeholders agreed on the need to focus their efforts on deploying

technologies designed to provide early benefits to users. These efforts led

to consensus on a phased approach to implementing free flight—beginning

with Free Flight Phase 1—including the core technologies to be used and

the locations where the technologies will be deployed under this first

phase, scheduled to be implemented by 2002. FAA has been working with

stakeholders to resolve differences among them and to better define its

planned limited demonstration, known as Flight 2000 (now the Free Flight

Operational Enhancement Program), which is designed to identify and

mitigate the risks associated with using free-flight-related communication,

navigation, and surveillance technologies and associated procedures. As a

result of these collaborative efforts, FAA and stakeholders—through

RTCA—have agreed to a general roadmap for a restructured demonstration

to be conducted in fiscal years 1999-2004. However, unresolved issues

remain, including the need to secure funding and develop additional plans.

Progress Toward

Implementing Free

Flight

Recommendations

In its October 1995 report, RTCA discussed the benefits of free flight and

included recommendations and time frames for users and FAA to consider

for implementing free flight.13 These recommendations, many of which

have several initiatives, emphasized, among other things, the

(1) consideration of human factors during all phases of developing free

12The Host computer is the centerpiece information-processing system in FAA’s en route centers. It

processes flight, radar, and display data for use by controllers. When FAA restructured the centerpiece

of its modernization program—the Advanced Automation System—in 1994, it canceled the segment

that included the Host replacement. FAA is currently acquiring the Host and Oceanic Computer

System Replacement to overcome hardware supportability problems and resolve Year 2000 date

requirements with the Host computer.

13Final Report of RTCA Task Force 3: Free Flight Implementation, RTCA (Oct. 1995).

Page 24 GAO/RCED-98-246 Free Flight Initiatives
Chapter 2 

FAA’s Efforts to Implement Free Flight

flight, (2) use of streamlined methods/procedures for system certification,

and (3) expansion of the National Route Program. The vast majority of

these recommendations (35 of 44) were to be completed in the near term

(1995 through 1997), 6 are focused on the midterm (1998 through 2000),

and 3 are to be completed in the far term (2001 and beyond). See appendix

I for a list of these recommendations.

Since late 1995, FAA and stakeholders have been working on various free

flight recommendations and many associated initiatives and, in August

1996, agreed on an action plan to guide their implementation.14 According

to FAA, through July 1998, they have fully implemented only 1 of the 35

near-term recommendations—to incorporate airline schedule updates,

such as delays and cancellations, into FAA’s Traffic Flow Management

system to help it reduce unnecessary restrictions and delays imposed on

airline operations. However, FAA and stakeholders have made substantial

progress in implementing many of the initiatives under the near-term

recommendations. For example, as outlined under a recommendation to

extend the benefits of data exchange, FAA has deployed digital

pre-departure clearances at 57 sites, which provide pilots with departure

information via digital cockpit displays and reduce the need for voice

messages. In addition, 49 of these sites have Digital Automatic Terminal

Information Service, which provides information about current weather,

airport, and facility conditions around the world. Digital communications

provide an advantage over voice communications by helping to relieve

congested voice frequencies and reduce the number of operational errors

that are caused directly or indirectly by miscommunication. Under another

recommendation, FAA is working with stakeholders through an RTCA task

force to find ways to reduce the time and cost associated with the agency’s

process for approving new technologies for flight operations. To address

another recommendation, FAA has deployed a technology, on a limited

basis, for controllers’ use that is expected to improve the sequencing of air

traffic as aircraft enter, leave, and operate within terminal airspace.

Work is under way on six midterm and three far-term recommendations

and their associated initiatives. For the most part, these recommendations

focus on incremental improvements to the core technologies that are

being deployed under Free Flight Phase 1 and those planned for

deployment under Flight 2000 (now the Free Flight Operational

Enhancement Program). For example, in the midterm, FAA has begun to

modify controllers’ workstations and supporting computer equipment to

accept, process, and display data received from satellites. In addition,

14Free Flight Action Plan, RTCA (Aug. 1996).

Page 25 GAO/RCED-98-246 Free Flight Initiatives
Chapter 2 

FAA’s Efforts to Implement Free Flight

under a far-term recommendation, FAA is studying the feasibility of using

satellite-based information to provide more precise information for

landing during periods of limited visibility.

FAA also noted that while it was in the early stages of planning for the

implementation of free flight, it took steps to maximize the air traffic

control system’s capacity and efficiency by extending flexibilities to

users—to select and fly more efficient flight paths when operating in

designated altitudes/areas—through programs such as the National Route

Program (NRP).

Existing Programs

Extend Some

Flexibility to Users

FAA has two early efforts under way to allow users (under certain

conditions) to select routes and procedures that will save them time and

money—NRP and the Future Air Navigation System (FANS). Established in

1990, NRP is intended to conserve fuel by allowing users to select preferred

or direct routes. FAA estimates that NRP saves the aviation industry over

$40 million annually. These savings are realized, in part, because pilots are

allowed to take advantage of favorable winds or minimize the effects of

unfavorable winds, thereby reducing fuel consumption. Initially allowed

only at higher altitudes, the program has been expanded to include

operations down to 29,000 feet. FAA is also working to decrease, where

appropriate, the present restriction that flights must be 200 miles from

their point of departure before they can participate and must end their

participation 200 miles prior to landing.

FANS uses new technologies and procedures that enhance communication

between pilots and air traffic controllers and provide more precise

information on the position of aircraft—allowing for improvements in air

navigation safety and in the ability of air traffic controllers to monitor

flights. Used primarily over the oceans and in remote areas normally out of

the range of ground-based navigation aids, FANS uses digital

communication more than voice communication to exchange information

such as an aircraft’s location, speed, and altitude. Although FANS is

gradually being implemented in many regions and countries, the aviation

community believes that for its full operational benefits (such as time and

fuel savings) to be realized, air traffic control procedures need to be

modified to shorten the distance currently required between aircraft. They

also contend that FAA needs to deploy the promised hardware and

software (Automatic Dependent Surveillance or ADS15) infrastructure for

15ADS is a surveillance technology that will provide more accurate position reports for use by

controllers and pilots to safely reduce distances between aircraft and make more efficient use of

airspace. ADS would permit controllers to see traffic in places previously outside of radar coverage.

Page 26 GAO/RCED-98-246 Free Flight Initiatives
Chapter 2 

FAA’s Efforts to Implement Free Flight

FANS in facilities that support airline operations primarily over the Pacific

Ocean in order for these benefits to be realized.

FAA’s Efforts to Reach

Consensus Lead to

Free Flight Phase 1

In November 1997, the FAA Administrator began an outreach effort with

the aviation community to build consensus on and seek commitment to

the future direction of the agency’s modernization program. As part of this

effort, she formed a task force of senior transportation officials, union

leaders, and executives and experts from the aviation community to assess

the agency’s modernization program—including the NAS architecture—and

develop a plan for moving forward.16 Much as we found in reviewing the

system’s logical architecture in February 1997, the task force found that

the architecture under development appropriately built on the concept of

operations for the NAS and identified the programs necessary to meet

users’ needs.17 However, the task force found that the architecture was

insufficient because of issues associated with cost, risk, and lack of

commitment from users.

In response, the task force recommended a phased approach that would

cost less, focus more on providing near-term benefits to users, and

modernize the NAS incrementally. Many of the initiatives identified under

the near- and midterm recommendations will be included under this

phased approach because these initiatives are expected to provide early

benefits for users. A central tenet of this approach is the “build a little, test

a little” concept of technology development and deployment—intended to

limit efforts to a manageable scope, identify and mitigate risks, and deploy

technologies before the system is fully mature when they can immediately

improve the system’s safety, efficiency, and/or capacity. Such a phased

approach to implementing free flight was designed to help the agency

avoid repeating past modernization problems associated with overly

ambitious cost, schedule, and performance goals and to restore users’ faith

in its ability to deliver on its promises.

As a first step toward the phased implementation of free flight, FAA—in

coordination with stakeholders—outlined a plan for Free Flight Phase 1 in

16This group is known as the Administrator’s NAS Modernization Task Force.

17In February 1997, we identified shortcomings in two main areas: FAA’s systems architecture lacked a

technical architecture and an effective enforcement mechanism. A technical architecture details the

specific information technology and communication standards and approaches that will be used to

build the systems, including those that address critical hardware, software, communication, data

management, security, and performance characteristics. It ensures that the systems interoperate

effectively and efficiently. FAA is developing a technical architecture as we recommended. See Air

Traffic Control: Complete and Enforced Architecture Needed for FAA Systems Modernization

(GAO/AIMD-97-30, Feb. 3, 1997).

Page 27 GAO/RCED-98-246 Free Flight Initiatives
Chapter 2 

FAA’s Efforts to Implement Free Flight

early 1998. This plan is expected to be implemented by 2002. As currently

envisioned, Free Flight Phase 1 calls for the expedited deployment of

certain NAS technologies. The technologies—which are at various stages of

development and will be further refined and tested are the (1) Controller

Pilot Data Link Communications (CPDLC) Build 1, (2) User Request

Evaluation Tool (URET), (3) Single Center Traffic Management Advisor

(TMA), (4) Collaborative Decision Making (CDM), (5) Surface Movement

Advisor (SMA), and (6) Passive Final Approach Spacing Tool (pFAST). In

general, these technologies are expected to provide tools for controllers

that will help to increase the safety and capacity of the air traffic control

system and benefit users through savings on fuel and crew costs. For

example, FAA and many stakeholders believe that TMA and pFAST should

improve controllers’ ability to more efficiently sequence traffic to improve

its flow in crowded terminal airspace.

Similarly, they believe the URET conflict probe will improve controllers’

ability to detect and resolve potential conflicts sooner than present

technology allows. However, in June 1998, the air traffic controllers’ union

at one of the two en route centers where URET is being tested asked that its

use be terminated until several concerns about its use in the current

environment can be resolved.18 Termination did not occur at this facility,

and the issue has been elevated to the regional level within FAA for

resolution. See appendix II for a summary of the status of the

recommendations related to Free Flight Phase 1.

The aviation community generally agrees on the core technologies for

Free Flight Phase 1 and on the locations proposed for deploying and

testing these technologies. See figure 2.1 for these sites. In addition, FAA is

currently developing a Free Flight Phase 1 plan that will provide more

details on implementing the program and recently appointed a program

manager to lead this effort.

18Controllers at the Indianapolis en route center are concerned that the use of URET has become a

“distraction” when they switch from using URET (without flight strips) to standard operating

procedures (with flight strips) and that this transition can impair their awareness of sector operations.

In addition, controllers maintain that using URET has increased their workload by requiring them to

enter data twice—into both URET and the Host computer.

Page 28 GAO/RCED-98-246 Free Flight Initiatives
Chapter 2 

FAA’s Efforts to Implement Free Flight

Figure 2.1: Proposed Locations for Deploying and Testing Free Flight Phase 1 Technologies1,2,3

1

CO CA

TX

MN

MO

OH

TN

FL

GA

IL IN

IA

NY

Oakland

Los Angeles

Ft. Worth

Denver

Kansas City

Memphis

Minneapolis

Chicago

Indianapolis

Cleveland

Miami

Washington, DC

New York

Atlanta

TMA- Traffic Management Advisor.4,6 An 

automated tool which assists en route controllers 

in metering aircraft to terminal areas.

pFAST- Passive Final Approach Spacing 

Tool.5,6,8 An automated tool which provides 

terminal controllers with sequence numbers and 

runway assignments for arrival aircraft. 

URET- User Request Evaluation Tool. An 

automated tool which assists en route controllers 

in identifying conflicts up to 20 minutes in advance 

of their occurrence.

CPDLC-1- Controller Pilot Data Link 

Communications, Build 1.9 A two-way data link 

communication between the ground controller and 

pilot using predefined messages.

SMA- Surface Movement Advisor.7 A system 

which facilitates sharing of dynamic information 

among airspace users, airport operators and air 

traffic controllers to enhance efficiency of surface 

movement.

1 Operational by 1998-2002.

2 Assumes no impact on other programs.

3 Risks need to be identified and a risk mitigation plan established and implemented in coordination 

with RTCA.

4 In 1998, launch R&D program to develop tools to expedite arrivals in complex airspace–at PHL 

(Philadelphia International Airport)–(outside funding scope of FFP1).

5 By June 1998, determine feasibility of implementing stand-alone pFAST without multi-center TMA, 

and implement accordingly (outside funding scope of FFP1).

6 Begin development after completion of current airspace review and design.

7 Functionality different from SMA at Atlanta.

8 Stand-alone pFAST without single-center TMA.

9 It has not yet been determined whether the selected site will be Minneapolis or Miami. A final 

decision by FAA is expected to be made in early 1999.

Page 29 GAO/RCED-98-246 Free Flight Initiatives
Chapter 2 

FAA’s Efforts to Implement Free Flight

Note: CDM is another Free Flight Phase 1 technology. It provides a real-time exchange of

information on flight plans and system constraints to assist airline and air traffic control personnel

in making decisions about NAS resources. As such, its use is not associated with specific

locations.

As a companion effort, FAA has charged RTCA with responsibility for

building consensus within the aviation community on how best to revise

the vision for modernization (operational concept) and to develop the

blueprint (architecture/framework) for carrying out the modernization. It

is critical that the vision for modernization and the blueprint for

implementing this vision be tightly integrated to help ensure that free flight

activities are coordinated and working toward common goals.

Plans for Free Flight

Demonstration Still

Under Development

In January 1997, Vice President Gore announced an initiative—Flight

2000—to demonstrate and validate the use of navigation capabilities to

support free flight. FAA then expanded Flight 2000 to include

communication and surveillance technologies. FAA viewed Flight 2000 as

an exercise for testing free flight technologies and procedures in an

environment where safety hazards could be minimized. FAA expected the

Flight 2000 program to validate the benefits of free flight, evaluate

transition issues, and streamline the agency’s procedures for ensuring that

new equipment is safe for its intended use.

Proposed primarily for Alaska and Hawaii, Flight 2000 would have tested

communication, navigation, and surveillance technologies, such as the

Global Positioning System (GPS) and its augmentations, the Wide Area

Augmentation System (WAAS) and the Local Area Augmentation System

(LAAS);19 Controller Pilot Data Link Communications (CPDLC); and ADS-B

technology. FAA initially selected these locations because they offer a

controlled environment with a limited fleet, which includes all classes of

users, all categories of airspace, and wide ranges of weather conditions

and terrain. However, many in the aviation community questioned whether

the lessons learned in Alaska and Hawaii would apply to operations in the

continental United States. At their urging, FAA agreed to add at least one

site within the continental United States to the Flight 2000 demonstration.

19GPS is a network of 24 satellites that transmit radio signals that allow properly equipped users—in

the air, on land, and at sea—to calculate the time, their positions and speed, and weather conditions.

However, as currently designed for military purposes, GPS can provide only limited service to civil

aviation. FAA is developing WAAS and LAAS to enhance GPS by correcting signal errors, increasing

satellite coverage, and providing timely warnings to users of malfunctions to allow GPS to satisfy

FAA’s requirements for integrity, accuracy, and availability. GPS needs to satisfy these requirements if

it is to become a primary means of navigation for free flight operations.

Page 30 GAO/RCED-98-246 Free Flight Initiatives
Chapter 2 

FAA’s Efforts to Implement Free Flight

Collaborative efforts between FAA and stakeholders on Flight

2000—through RTCA—have led to broad consensus on a general roadmap

for restructuring this demonstration program, including four criteria for

selecting the candidate operational capabilities to be demonstrated. In

general, under these criteria (1) industry and FAA must address all aspects

of modernization to be successful in moving toward free flight;

(2) expected benefits are the major reason for implementing a given

capability; (3) the capability does not interfere with or slow down any

near-term activities; and (4) the risks associated with operational

capabilities that require integrating multiple communication, navigation,

and surveillance technologies should be addressed.

Using these criteria, FAA and stakeholders reviewed over 70 potential

operational capabilities and selected 9 of them. They also recommended

demonstration locations in the Ohio Valley and Alaska. (See app. III for a

description of these capabilities and the expected operational benefits.)

For example, under this proposal, FAA would provide more accurate

weather information to pilots and controllers to improve safety and

potentially reduce flight times. In addition, FAA would improve airport

surface navigation capabilities by providing pilots (and operators of other

surface vehicles) with moving maps that display traffic in low-visibility

conditions. FAA and stakeholders also recommended that the program be

renamed the “Free Flight Operational Enhancement Program.”

Stakeholders and FAA recognize that more detailed planning is needed—to

identify risk-mitigation activities, select the final site, and estimate costs,

schedules, and the number of required aircraft—and that this planning will

require close coordination between FAA and industry to ensure that plans

are consistent with stated operational capabilities and are achievable by

FAA and users. FAA is currently considering the proposed RTCA roadmap for

the restructured Flight 2000 demonstration and expects to reach a

decision in the fall of 1998. If approved as scheduled, a detailed plan is

expected by the end of 1998.

Page 31 GAO/RCED-98-246 Free Flight Initiatives
Chapter 3 

FAA and the Aviation Community Face

Many Challenges in Implementing Free

Flight Cost-Effectively

FAA’s plan to implement free flight through an evolutionary (phased)

approach is generally consistent with past recommendations that we and

others have made on the need for FAA to achieve a more gradual,

integrated, and cost-effective approach to managing its modernization

programs. However, FAA and stakeholders recognize that significant

challenges must be addressed if the move to free flight—including Free

Flight Phase 1 and Flight 2000 (now the Free Flight Operational

Enhancement Program) is to succeed. While FAA must address many of the

challenges, stakeholders recognize that, as partners, they must assist the

agency. The challenges for FAA are to (1) provide effective leadership and

management of modernization efforts—including cross-program

communication and coordination; (2) develop plans—in collaboration

with the aviation community—that are sufficiently detailed to move

forward with the implementation of free flight—including the

identification of clear goals and measures for tracking the progress of the

modernization efforts; (3) address outstanding issues related to the

development and deployment of technology—such as the need to improve

the agency’s process for ensuring that new equipment is safe for its

intended use and methods for considering human factors; and (4) address

other issues, such as the need for FAA to coordinate its modernization and

free flight efforts with those of the international community and integrate

free flight technologies.

Effective Management

Is the Key to

Implementing Free

Flight Successfully

FAA and stakeholders identified a number of managerial issues that will

need to be addressed if free flight is to be implemented successfully. For

example, (1) provide strong senior leadership to guide the implementation

of free flight both within and outside the agency and (2) implement an

evolutionary rather than a revolutionary approach to modernization.

Successfully addressing these issues will help the agency effectively

implement free flight.

FAA Needs to Exercise

Strong Leadership

Some FAA officials and stakeholders said that the agency will need to

provide strong leadership both inside the agency and within the aviation

community for free flight to be implemented successfully. For example,

some FAA officials and stakeholders said that the agency will need to

improve the effectiveness of its internal operations by encouraging

communication and cooperation between the various program offices

responsible for its free flight efforts. Additionally, some FAA officials and

stakeholders said that the agency will need to continue efforts to build

Page 32 GAO/RCED-98-246 Free Flight Initiatives
Chapter 3 

FAA and the Aviation Community Face

Many Challenges in Implementing Free

Flight Cost-Effectively

consensus among the aviation community and gain its commitment to the

direction of the agency’s plans for modernization.

Effective Leadership Is Needed

Within FAA

Some FAA officials and stakeholders told us that improvements in

communication and coordination across FAA program offices are needed to

implement free flight successfully. For example, one FAA official told us

that the primary challenge facing the agency in its efforts to implement

free flight is developing effective communication and coordination across

program lines. Some stakeholders shared this concern, observing that the

various program offices within FAA do not communicate well or effectively

coordinate their activities. Thus, according to some within FAA and

stakeholders, despite the agency’s move to using cross-functional,

integrated product teams20 to improve accountability and coordination

across FAA, these teams have become insular and some team members

tend to be motivated primarily by the priorities and management of the

offices that they represent rather than the goals of a given team. One

stakeholder stressed that the effectiveness of these teams has also been

limited by (1) inadequate training of members on how to operate a team

and (2) the fact that these teams are given responsibility for projects

without the commensurate authority they need to carry out their

responsibilities. Some stakeholders also noted that the agency has not

made a number of decisions about modernization because of ongoing

disagreements among various program offices over how best to proceed

with its various components, such as the selection of new free flight

technologies for communicating information digitally rather than by voice.

The concerns cited above are consistent with our prior work on FAA’s

culture as it affects acquisition management.21 In particular, we found that

the agency has previously had difficulty communicating and coordinating

effectively across traditional program lines. In addition, we learned from

some FAA staff and functional managers that FAA has encountered

resistance to the integrated product team concept and these teams’

operations. As we reported, one major factor impeding coordination has

been FAA’s organization into different divisions whose “stovepipes,” or

upward lines of authority and communication, are separate and distinct.

Because FAA’s operational divisions are based on a functional specialty,

20Integrated product teams are designed to be cross-functional teams that are responsible for

developing or procuring new equipment. The goals of these teams are to improve accountability and

coordination and infuse a more strategic, mission-oriented focus into the acquisition process. Team

members include contractors, FAA’s engineering division, and the FAA divisions that operate and

maintain air traffic control equipment.

21Aviation Acquisition: A Comprehensive Strategy Is Needed for Cultural Change at FAA

(GAO/RCED-96-159, Aug. 22, 1996).

Page 33 GAO/RCED-98-246 Free Flight Initiatives
Chapter 3 

FAA and the Aviation Community Face

Many Challenges in Implementing Free

Flight Cost-Effectively

such as engineering, air traffic control, or equipment maintenance, getting

the employees in these units to work together has been difficult. Internal

and external studies have found that the operations and development

sides of FAA have not forged effective partnerships.

To its credit, FAA is currently attempting to improve cross-agency

communication and coordination by developing incentives for staff to

work toward the agency’s goals and priorities. Plans are also under way to

develop contracts with each integrated product team to hold its members

accountable for developing and deploying a given operational capability.

According to FAA officials, these contracts are intended to improve

accountability for delivering technologies; in the past, such accountability

has not been clearly assigned. In addition, efforts are under way to work

with the aviation community to resolve disagreements that have persisted

among FAA program offices, such as how to proceed with the use of digital

communication.

FAA Needs to Exercise Strong

Leadership in Delivering on Its

Commitments to the Aviation

Community

While stakeholders generally applaud FAA’s efforts to build consensus

among stakeholders, some believe that the agency must be prepared to

exercise strong leadership by (1) making difficult decisions after weighing

stakeholders’ competing priorities, (2) holding to these decisions even

amidst new and conflicting opinions about the value of one course of

action over another, and (3) delivering on its commitments. Some

stakeholders said they were particularly frustrated when, after announcing

a planned course of action, FAA later delayed its implementation or

retracted it and moved in a different direction. Some stakeholders told us

that such indecision makes it very difficult for them to make plans for the

future—such as determining investments for avionics upgrades—and

further erodes their confidence in the agency’s ability to manage

modernization programs and provide leadership to the aviation

community. For example, several stakeholders cited FAA’s failure to deliver

the ground-based infrastructure, needed for users to accrue benefits from

equipping with new technologies under the Future Air Navigation System

program, as a warning signal to them to proceed cautiously, since the

agency may not deliver on its promises. In particular, users are concerned

that if they invest in new technologies, they will not realize benefits in a

timely manner to offset these investments.

Page 34 GAO/RCED-98-246 Free Flight Initiatives
Chapter 3 

FAA and the Aviation Community Face

Many Challenges in Implementing Free

Flight Cost-Effectively

FAA Needs to Effectively

Implement an Evolutionary

Approach to Technology

Development and

Deployment

Some stakeholders believe that for FAA to successfully implement free

flight, it must demonstrate that it can effectively manage its air traffic

control modernization programs and deliver promised capabilities. To do

so, FAA will need to implement an evolutionary approach to technology

development and deployment. According to FAA, under such an approach,

it will limit the scope of project segments so that it can deploy, test,

evaluate, and refine a given technology until it obtains the desired

capabilities. One stakeholder familiar with this approach emphasized the

importance for FAA, in implementing it, of (1) assessing risks,

(2) developing metrics, (3) limiting the scope of each phase of

development, (4) evaluating progress before moving forward with the next

phase of development, and (5) retraining staff. These steps would be

applied to each cycle of the development process to help ensure that each

completed iteration results in enhanced capabilities and moves a given

technology closer to its desired level of maturity. FAA agreed that each of

these steps will be important for successfully implementing this approach.

FAA has not yet developed detailed plans for implementing this approach;

however, in concept, it is consistent with our past recommendations that

the agency avoid taking on unrealistic cost, schedule, and performance

goals. For example, the recently developed plans for revising the Flight

2000 demonstration recommend an incremental approach, under which

operational capabilities will be introduced over time into planned field

demonstration sites. FAA and users expect such an approach will allow

them to achieve success by taking smaller, less risky, more manageable

steps. Some stakeholders told us that although they are encouraged by

FAA’s efforts to date, they are taking a wait-and-see attitude as to whether

the agency can effectively implement this approach to technology

development and deployment.

Clear Goals and

Measures and

Sufficiently Detailed

Plans Are Necessary

for Implementing Free

Flight

FAA and stakeholders have identified a wide range of concerns that need to

be addressed to help ensure that efforts to implement free flight are

sufficiently well developed as the agency moves forward with related

modernization activities. These concerns include, among others, the need

for (1) FAA—in collaboration with stakeholders—to develop clear goals

and objectives for what it intends to achieve, as well as a measurement

system for tracking progress, and (2) FAA and stakeholders to develop

detailed plans that will allow for the cost-effective implementation of free

flight.

Page 35 GAO/RCED-98-246 Free Flight Initiatives
Chapter 3 

FAA and the Aviation Community Face

Many Challenges in Implementing Free

Flight Cost-Effectively

Clear Goals and a Measurement

System Are Important to the

Successful Implementation of

Free Flight

While FAA and stakeholders agree on the basic premise of moving toward

free flight and the agency’s initial plans to deploy technologies under its

first phase, stakeholders told us that FAA—in collaboration with

them—needs to establish clear goals and objectives for what it intends to

achieve for this and other free flight efforts and a measurement system for

tracking progress. For example, a representative of a major systems

contractor believes that it is critical for FAA to clearly articulate its vision

and goals for where it intends to go with free flight so that the future

direction is clear to everyone involved. A representative of a major

airframe manufacturer agreed with this position and added that the agency

should focus on what the system will look like 10 to 20 years from now. In

this representative’s view, once this is determined, then the agency and

stakeholders should begin discussing the technologies and procedures

that will be needed for the future system.

In addition, the representative of the major airframe manufacturer

stressed that FAA is developing the NAS architecture from the bottom

up—merely inserting technologies into the air traffic control system rather

than focusing on how the entire system needs to change. According to this

representative, FAA is “putting the cart before the horse” by adhering to a

replacement technology philosophy—“keep doing what we are doing but

with automation support.” The real challenge is to rethink the operation

first, including the roles of people and automation, and then decide which

technologies and procedures to use. Some FAA officials and stakeholders

stressed that this approach will require long-range research programs that

currently do not receive enough priority in the agency’s plans because of

resource constraints.

As for a measurement system, some FAA officials and stakeholders said

that before developing performance measurements, the agency will need

to develop baseline data to use as a benchmark for tracking its progress in

implementing free flight. These stakeholders noted that without a concrete

sense of where the agency is now in terms of capacity, efficiency, and

other measures, progress is difficult to measure.

Calls for these types of measures are consistent with the requirements of

the Government Performance and Results Act of 1993, which emphasizes

the need for agencies to clearly define their missions, establish long-term

strategic goals, and measure their performance against the goals they have

set. With firm baseline data, FAA will be in a better position to develop

measures to track its progress as it proceeds to implement free flight.

Some FAA officials and stakeholders acknowledged that developing such

Page 36 GAO/RCED-98-246 Free Flight Initiatives
Chapter 3 

FAA and the Aviation Community Face

Many Challenges in Implementing Free

Flight Cost-Effectively

measurements is difficult, and as part of Free Flight Phase 1, the aviation

community (airlines, DOD, and other stakeholders) will provide FAA with

information to establish baseline measures. FAA officials also said that

supplemental performance data will be needed to track progress. In

addition, FAA and stakeholders have proposed measures for tracking

progress that will be used in conjunction with the revised Flight 2000

demonstration.

Performance measures are also required under FAA’s new acquisition

management system. The Congress directed FAA in 1995 to develop this

new system to improve the timeliness and cost-effectiveness of the

agency’s acquisition of equipment.22 The new system includes

requirements to improve the agency’s management of modernization

programs, including (1) identifying critical shortfalls in the NAS’ capability

and technologies that could be used, among other things, to improve the

NAS’ safety and efficiency; (2) establishing critical performance parameters

and benefits that a program must achieve and setting boundaries for cost

and schedule; and (3) developing metrics of critical performance

measures, such as time, cost, and customer satisfaction. According to FAA,

it has followed this system for acquiring the individual free flight

technologies. FAA also indicated that it plans to use both Free Flight Phase

1 and Flight 2000 (now the Free Flight Operational Enhancement

Program) to gather the data needed to conduct investment analyses before

deploying free flight technologies on a larger scale.

Detailed Plans Are Needed

for Implementing Free

Flight

Stakeholders believe that more detailed plans are needed to provide the

aviation community with assurances that moving forward with free flight

is warranted. They believe that these plans should include the results of

cost/benefit analyses, new procedures, and schedules for equipment

installation.

Users Seek Assurance That

Technology Investments Will

Provide Benefits

Because they expect that equipping with free flight technologies will be

expensive, many users believe that FAA needs to demonstrate the

near-term benefits of the new equipment—especially given FAA’s poor

record of delivering promised benefits. As part of its efforts to develop

plans for implementing free flight, FAA has conducted cost/benefit analyses

to provide justification for free flight investments. However, stakeholders

have raised concerns that these analyses have focused almost exclusively

on the benefits to FAA. As a result, they believe that these analyses are of

22P.L. 104-50 directed FAA to develop a new acquisition management system, which the agency

implemented in Apr. 1996.

Page 37 GAO/RCED-98-246 Free Flight Initiatives
Chapter 3 

FAA and the Aviation Community Face

Many Challenges in Implementing Free

Flight Cost-Effectively

little value to users that must make business decisions about investing in

new technologies. As one airframe manufacturer noted, FAA should

develop a convincing case for changing the functions of the present

system before selecting new technologies.

While users expressed a desire for studies that consider their business

needs, one airline official told us that meaningful cost/benefit analyses are

very difficult to establish for the airline industry because the costs and

benefits of equipping will vary considerably both among and within

airlines. For example, the cost of investments and associated benefits will

vary with factors such as (1) the cost of installing new avionics—including

the cost of retrofitting older aircraft, (2) the timing of requirements for

completing the installation of equipment, and (3) the routes flown. Even

though these factors vary from one airline to another, some airlines expect

FAA to conduct analyses that demonstrate that technology investments will

be cost-effective for them.

Similarly, DOD and general aviation users are concerned about potential

penalties for not equipping their aircraft with technologies that will be

needed to conduct operations under free flight. For example, DOD officials

told us that they need more detailed information about whether—or under

what circumstances—they may be excluded from certain airspace if they

fail to equip with free flight technologies. DOD is also concerned that the

lack of specificity in FAA’s plans may negatively affect its ability to meet its

mission readiness requirements—including the ability to fly cost-efficient

and effective routes. Some stakeholders have expressed concern that the

cost of equipping with avionics for participation in the free flight

environment may be prohibitive for the recreational end of the general

aviation community. FAA is aware of this concern and plans to use the

Flight 2000 demonstration (now the Free Flight Operational Enhancement

Program) as a means for streamlining its process for ensuring the safety of

new equipment for flight operations and developing affordable avionics for

general aviation.

New Procedures for Free Flight

Need to Be Developed

A number of stakeholders told us that in order for FAA and users to fully

exploit new capabilities to maximize the air traffic control system’s safety,

capacity, and efficiency, the agency will need to develop procedures that

will be used in the free flight environment. Such procedures will affect a

wide range of operations. For example, new procedures will be required to

approve, integrate, and deploy new technologies. New procedures will

also be needed to enable pilots and controllers to use the new

technologies. Hence, some stakeholders noted that it will be important for

Page 38 GAO/RCED-98-246 Free Flight Initiatives
Chapter 3 

FAA and the Aviation Community Face

Many Challenges in Implementing Free

Flight Cost-Effectively

FAA to make explicit any changes in pilots’ and controllers’ roles and

responsibilities. For example, if pilots and controllers are to share

responsibility for making decisions about altitudes, speeds, and routes, the

procedures need to be well defined. Under Free Flight Phase 1, the agency

plans to implement new procedures as needed to demonstrate the use of

new air traffic management tools that controllers will use to improve

conflict detection and air traffic sequencing, among other things. Similarly,

under Flight 2000 (now the Free Flight Operational Enhancement

Program), FAA plans to develop new procedures for the new

communication, navigation, and surveillance technologies that will be

used by pilots and controllers.

FAA is aware of the need to develop procedural changes for operations

under free flight and is currently working with the aviation community to

develop these new procedures. However, some stakeholders are

concerned that the development and implementation of new procedures

will not occur in a timely fashion. One of these stakeholders further

stressed that having new equipment and technology working together is

not enough, without new procedures, to deliver the benefits promised

under free flight.

Equipment Installation Will

Require Adequate Lead Time

Commercial airlines and DOD require adequate lead time to plan for the

cost-effective installation of new equipment. To facilitate an efficient

equipment installation process, FAA will need to work with users to

consider their unique needs as they develop plans for moving to free flight

operations. For example, to minimize costs, airlines would prefer to install

new avionics within an aircraft’s regularly scheduled maintenance cycle.

In addition, airlines do not want to install new equipment too early

because they want to be able to take advantage of opportunities to

purchase the best technologies at the lowest cost; however, they do not

want to equip too late and miss out on the benefits. Similarly, because DOD

must request funding well before installing new equipment, it needs ample

lead time to develop budget requests and installation schedules for many

of its aircraft, which number more than 16,000. Therefore, it is important

for FAA to make timely decisions about future technology requirements

and stick with those decisions to give all aviation user groups the lead time

needed to ensure that their purchases are cost-effective and their

installation schedules are efficient.

To provide for a smooth transition, FAA has been working with DOD and

other users to move forward with the selection of new technologies for

operations under free flight. FAA’s most recent draft NAS architecture

Page 39 GAO/RCED-98-246 Free Flight Initiatives
Chapter 3 

FAA and the Aviation Community Face

Many Challenges in Implementing Free

Flight Cost-Effectively

(blueprint) represents the agency’s attempt to provide the level of detail

requested by the aviation community. However, some stakeholders have

expressed concern that the draft architecture is too general to use in

planning for future technology upgrades. For example, an airline

representative noted that when airlines place orders for new aircraft, they

request systems that provide maximum flexibility for later modifications

or upgrades. However, future free flight equipment upgrades will still be

costly, and the sooner FAA decides which technologies will be required for

operations under free flight, the more effectively airlines can plan for

those upgrades.

Effective Collaboration

With Stakeholders Is Key

to Developing

Implementation Plans

Collaboration between FAA and stakeholders is critical to developing plans

that will have the level of buy-in needed to start implementing free flight.

FAA’s recent experiences in developing modernization plans have pointed

to the need to work collaboratively with the aviation community from the

onset of a given program to help ensure the effective resolution of issues

as plans are developed. In March 1998, FAA and the aviation community

reached consensus to begin implementing Free Flight Phase 1—including

consensus on which technologies will be deployed and where. In addition,

under this first phase, steps will be taken to identify and mitigate the risks

associated with inserting new technologies and procedures into an

operating air traffic control system.

In contrast, until recently FAA and stakeholders have been sharply divided

over the agency’s plans for conducting Flight 2000—a limited

demonstration of free-flight-related communication, navigation, and

surveillance technologies—primarily in Alaska and Hawaii. Problems

began when the proposal was announced without consulting users and

have persisted, despite FAA’s efforts to work collaboratively with

stakeholders to resolve them. While many stakeholders we interviewed

agreed with the need for FAA to conduct an operational demonstration of

free flight technologies and related procedures, they had strong

reservations about the utility of conducting such a demonstration in

Alaska and Hawaii. In their view, few of the lessons learned would be

transferable to operations in the continental United States, where free

flight implementation will ultimately focus. In addition, stakeholders

expressed concern that FAA has not focused enough attention on

developing the detailed plans that it needs for conducting the

demonstration, as required by the agency’s acquisition management

system. In fact, the Department of Transportation’s fiscal year 1998

appropriation act prohibited FAA from spending any fiscal year 1998 funds

Page 40 GAO/RCED-98-246 Free Flight Initiatives
Chapter 3 

FAA and the Aviation Community Face

Many Challenges in Implementing Free

Flight Cost-Effectively

on the Flight 2000 program. In the accompanying Conference Report for

the act, the conferees noted that additional financial and technical

planning was needed before the Flight 2000 demonstration program could

be implemented. The Congress has not yet decided whether to fund this

demonstration program in fiscal year 1999.

To address these concerns, FAA has been working collaboratively with

stakeholders—through RTCA—to develop a roadmap (general plans) for

restructuring Flight 2000. These efforts have resulted in the

(1) development of selection criteria for the operational capabilities to be

used, (2) selection of demonstration sites in Alaska and the Ohio Valley,

(3) selection of nine operational capabilities (see app. III), (4) proposed

change of the program’s name from Flight 2000 to the “Free Flight

Operational Enhancement Program,” and (5) revision of the time frame

(1999-2004) for conducting the demonstration program. FAA is currently

considering this RTCA proposal. FAA and stakeholders realize that they will

need to continue to work collaboratively to refine these plans. The latest

collaborative efforts appear to be a positive step toward developing the

type of detailed plans FAA needs to carry out the demonstration and secure

the necessary funding.

FAA Needs to Address

Outstanding Issues

Related to Technology

Development and

Deployment

Stakeholders and FAA officials identified several concerns about

technology development and deployment that need to be resolved. Key

among these were (1) the pace and cost of the agency’s process for

ensuring that new equipment is safe for its intended use, (2) issues related

to human factors, (3) uncertainties surrounding the use of GPS as a sole

means of navigation, and (4) issues associated with the use of digital

communication technologies.

Efforts Are Under Way to

Address Shortcomings of

FAA’s Certification Process

Many stakeholders and FAA officials stated that FAA’s certification

process—methods for ensuring that new equipment is safe for its intended

use—is a key challenge to the implementation of free flight because it

takes too long and costs too much; they urged that the process be

streamlined. The certification process could be problematic for free flight

because many new types of equipment, such as those that are required for

the use of new digital communication technology, will need to be certified

before they can be implemented. As one aviation community stakeholder

noted, “If something is going to change the aviation system, it has to go

through the certification knot hole.”

Page 41 GAO/RCED-98-246 Free Flight Initiatives
Chapter 3 

FAA and the Aviation Community Face

Many Challenges in Implementing Free

Flight Cost-Effectively

Recognizing that the certification process poses a barrier to implementing

free flight, FAA has taken a number of steps to address this problem. For

example, FAA asked, and RTCA agreed, to convene a task force to examine

ways to improve the agency’s existing certification practices. The first

meeting took place in June 1998, and the task force expects to report to

FAA within 6 months. Among other things, this task force will (1) develop

baseline information on the current system—including a review of

avionics, infrastructure, and satellite needs; (2) consider human factors in

the certification process—including how best to integrate human factors

into the system’s design and operations; (3) identify ways to improve the

current certification process—including an attempt to determine an

acceptable range of failure for technologies and metrics for technology

design and performance; and (4) review FAA’s certification

services—including what customers should expect from the agency and

alternative methods of satisfying certification requirements, such as

granting approval authority for specific types of technologies to Centers of

Excellence or individuals. In addition, RTCA has a special committee that is

reviewing the use of digital communication technologies for free flight,

including the development of standards that FAA could use to develop

certification requirements. Furthermore, the agency plans to use the Flight

2000 (now the Free Flight Operational Enhancement Program)

demonstration of free flight communication, navigation, and surveillance

technologies as an opportunity for streamlining the agency’s equipment

certification process.

Several stakeholders told us that while the certification process could be

streamlined, both FAA and stakeholders need to take a careful approach.

They noted that the present system may be cumbersome, but it is

providing the desired level of safety. If standards are going to be relaxed,

then redundancies need to be built into the system to ensure that

modifications to the certification process either maintain or improve upon

existing levels of safety.

Implementation of Free

Flight Hinges on the

Satisfactory Resolution of

Human Factors Issues

Many stakeholders told us they believe that the successful implementation

of free flight hinges on issues related to human factors, such as the ability

and willingness of pilots, controllers, and maintenance staff to shift to a

new system of air traffic management. Among the concerns raised are the

need to (1) define the type of training that will best prepare human

operators for the transition; (2) provide a reasonably paced training

schedule to help ensure that pilots, controllers, and maintenance staff, in

particular, are not overburdened with too many changes at one time; and

Page 42 GAO/RCED-98-246 Free Flight Initiatives
Chapter 3 

FAA and the Aviation Community Face

Many Challenges in Implementing Free

Flight Cost-Effectively

(3) identify the risks associated with changes in technologies and

procedures and the potential effects of these changes on human

operations in a free flight environment. For example, a recent report by

the National Research Council on human factors and automation raised

concerns that, among other things, the increased use of automation may

lead to confusion among pilots, controllers, and airline operations

personnel over where control lies, especially in a free flight environment.23

As a result, the report recommended that until these and other human

factors issues are better understood, the introduction of automated tools

should proceed gradually and decision-making authority should continue

to reside on the ground with controllers.

A related issue is the need to incorporate the consideration of human

factors into the product development cycle to avoid costly and

cumbersome changes at the end of the development process. An FAA

human factors official told us that FAA has learned a lot from its experience

with the Standard Terminal Automation Replacement System (STARS)

about the need to involve users in considering human factors throughout

the product development cycle—from the mission needs statement,

forward.24 This official stressed that the agency can pay to consider human

factors throughout the acquisition cycle or pay more later, as it is doing

with STARS, to fix the problems that arise when these factors are not

considered. Furthermore, when human factors are not considered along

the way, problems cannot always be fixed. Fewer options are available at

the end of a development cycle for modifying a given technology.

Stakeholders agreed with this assessment.

While FAA has developed guidelines for considering human factors during

the technology development process, it has not established a formal

requirement for using these guidelines. In June 1996, we reported that

FAA’s work on human factors was not centralized, and we recommended

that the Secretary of Transportation direct FAA to ensure that all units

coordinate their research through the agency’s Human Factors Division.25

According to some FAA officials and one stakeholder, such coordination is

23The Future of Air Traffic Control: Human Operators and Automation, National Research Council

(Feb. 1998).

24Both controller and maintenance worker unions identified numerous human factors problems with

STARS that need to be resolved before the system is deployed. According to union representatives,

many of these problems resulted because users were not adequately involved in the development of

this system. While progress has been made in addressing concerns identified by both unions,

outstanding issues remain, including the source of funds for implementing all solutions.

25Human Factors: Status of Efforts to Integrate Research on Human Factors Into FAA’s Activities

(GAO/RCED-96-151, June 27, 1996).

Page 43 GAO/RCED-98-246 Free Flight Initiatives
Chapter 3 

FAA and the Aviation Community Face

Many Challenges in Implementing Free

Flight Cost-Effectively

still lacking and the agency’s programs would benefit from assigning

responsibility for human factors to a higher level within FAA so that these

issues can receive sufficient attention from the agency’s senior

management. In addition, several stakeholders stressed the importance of

retaining the same members on teams that address concerns about human

factors through the entire development process. One of these stakeholders

believes that such continuity will help ensure that the team’s efforts are

not derailed late in the process by the inclusion of new members and the

introduction of a range of new issues and methods of resolving them.

Human factors must also be considered in the operating environments

where technologies will be deployed. According to one stakeholder

involved in human factors work, because the air traffic control system has

evolved—rather than being designed—it does not operate in a

homogeneous fashion, and when the system is changed, the effects on

humans can vary widely. For example, both en route and terminal facilities

tailor their operations in many ways to factor in local conditions. As a

result, this stakeholder stressed that as many as 1,000 letters of agreement

between various components of FAA and users making adjustments to

operating rules and procedures may exist—making it difficult for the

agency to generalize across the system when considering the introduction

of changes or improvements. In addition, under free flight, users and

controllers (as well as maintenance staff) will rely more heavily on

automated technologies to carry out their responsibilities—making the

integrity of the system even more critical than it is now and increasing the

need for more redundant systems and training to ensure that controllers

can successfully switch, if necessary, to manual control techniques.

FAA Needs to Determine if

GPS Augmentations Will

Provide the Primary or

Sole Means of Navigation

Satellite navigation provides precise information on the position of aircraft

and offers the potential for the required distances between aircraft to be

safely reduced and, in turn, for the air traffic control system’s capacity to

be increased. FAA initially planned its augmented satellite navigation

system to be a sole means of navigation under free flight.26 However, FAA

and stakeholders have expressed concerns about the vulnerability of an

augmented satellite system to both intentional and unintentional (e.g.,

radio frequency interference) jamming, and about problems associated

with the system’s weak signal. In view of these concerns, the Air Transport

Association and the Aircraft Owners and Pilots Association have, in

26If GPS were used as a sole means of navigation, aircraft would not be required to carry additional

types of equipment for navigation. However, if it were used as a primary means of navigation, aircraft

operators would be required to carry additional navigation equipment or to have additional restrictions

placed on when and where they can fly.

Page 44 GAO/RCED-98-246 Free Flight Initiatives
Chapter 3 

FAA and the Aviation Community Face

Many Challenges in Implementing Free

Flight Cost-Effectively

coordination with FAA, developed plans for a risk assessment of

augmentations to satellite navigation. A research organization was

selected in July 1998 to conduct the assessment, and a final report is

expected in January 1999.

An Air Transport Association official told us that this risk assessment will

address concerns about the vulnerability of satellite navigation and

stressed that such a study is critical because the use of satellite navigation

as a sole means of navigation is the centerpiece of FAA’s architecture

(blueprint) and is the basis for the agency’s cost/benefit analyses.

According to this official, a risk assessment is needed to identify the risks

and develop mitigation plans and cost estimates for mitigating each risk.

The results of this study could affect both the costs and benefits for FAA

and users because if FAA does not use the augmented system as a sole

means of navigation, it could incur additional costs to retain some portion

of its ground-based navigational aids. Similarly, users may find it necessary

to maintain existing equipment and to purchase new equipment under free

flight.

Users Await FAA’s

Decisions About Data Link

FAA and stakeholders consider digital communication

technologies—commonly referred to as data link—as critical to

implementing free flight. FAA expects that the use of data link—in

combination with other free flight technologies—will improve safety,

increase capacity, reduce costs, and enhance the productivity of humans

and equipment. Data link will replace or supplement many of the routine

voice interactions between pilots and controllers with nonvocal digital

data messages. For example, during peak periods, one controller often

may be required to communicate on a single radio channel with 25 or more

aircraft—leading to possible operational errors and system delays. FAA

believes that using data link will (1) reduce nearly one-quarter of all

domestic operational errors—caused directly or indirectly by

miscommunication between pilots and controllers, (2) relieve highly

congested voice communication channels, and (3) save the airlines

millions of dollars annually on communication-related delays that occur

during both taxi and in-flight operations.

Data link comprises three components: (1) software

applications—including Controller Pilot Data Link Communications

(CPDLC), weather information, and Automatic Dependent Surveillance

(ADS); (2) hardware systems installed on the ground and avionics in the

cockpit; and (3) the communication medium that allows for the transfer of

Page 45 GAO/RCED-98-246 Free Flight Initiatives
Chapter 3 

FAA and the Aviation Community Face

Many Challenges in Implementing Free

Flight Cost-Effectively

data between the ground and airborne equipment. FAA is responsible for

implementing ground systems, and the aviation community is responsible

for implementing airborne systems. As partners, both FAA and the aviation

community are responsible for ensuring the interoperability of these

systems.

Stakeholders told us that despite the importance of data link, many issues

remain unresolved. Chief among these issues is the lack of agreement

within FAA on how, when, and at what pace to proceed with the use of data

link. This lack of agreement may be attributed, at least in part, to the fact

that data link efforts are being managed and implemented by different

organizational elements of FAA and by the aviation community.

Recognizing this, FAA has been working with stakeholders to reach

agreement on data link issues. In May 1998, a group of FAA officials and

stakeholders under the Administrator’s NAS Modernization Task Force

began developing a consensus plan for implementing controller pilot data

link in the en route environment. In July 1998, this group presented its plan

to RTCA for consideration. In August 1998, RTCA modified the plan and

endorsed the implementation of CPDLC Build 1 as part of Free Flight Phase

1—recommending that the location and communication medium for CPDLC

Build 1 be changed. FAA—in consultation with stakeholders—intends to

further develop the plans for deploying CPDLC Build 1 by the end of 1998.

FAA’s approval is expected by early 1999.

Other Outstanding

Issues May Limit

Effectiveness of Free

Flight’s

Implementation

A number of other issues were identified by FAA officials and stakeholders

as needing resolution for free flight to be implemented successfully.

Among these issues were the need to (1) coordinate modernization

activities with the international aviation community, (2) integrate free

flight technologies, and (3) address airport capacity issues.

FAA Needs to Ensure

Global Coordination of Its

Modernization Efforts

Airlines that operate internationally and DOD believe that FAA needs to

work diligently to ensure that, to the extent possible, carriers do not have

to purchase multiple types of avionics to operate in different parts of the

world. Currently, both FAA and various elements of the aviation community

are working collaboratively with their international counterparts on a

number of modernization issues. For example, FAA is a member of an

airline-led group with international participation—including Eurocontrol27

27Eurocontrol is the organizational entity that addresses air traffic management issues for the

European member states.

Page 46 GAO/RCED-98-246 Free Flight Initiatives
Chapter 3 

FAA and the Aviation Community Face

Many Challenges in Implementing Free

Flight Cost-Effectively

and several foreign airlines—known as the Communication, Navigation,

and Surveillance/Air Traffic Management Focused Team. The purpose of

this team is to facilitate the implementation of new communication,

navigation, and surveillance and air traffic management technologies by

developing consensus among global airlines on economic issues. In

addition, the agency is working with the European community on human

factors issues and data link applications. However, some stakeholders

question the sufficiency of the agency’s efforts to coordinate technology

selection decisions that will allow users to operate worldwide. Because

the airline industry is becoming increasingly global, it requires the

development of compatible operational concepts, technologies, and

systems architectures throughout the world. One airframe manufacturer

noted that the airlines are increasingly demanding global solutions to

minimize the cost of changes to avionics and flight systems. The costs of

purchasing new avionics, retrofitting them into the aircraft (and the down

time required), and training pilots in their use for a large fleet of airplanes

will quickly exceed any benefits if these benefits are not realized as soon

as additional or improved capabilities are introduced.

According to some stakeholders, FAA has historically been the

international leader in air traffic control modernization efforts—a position

that has given the agency the flexibility to develop and deploy

technologies that best serve the needs of users in the United States.

However, many stakeholders expressed concern that FAA’s position as the

international leader in this arena has eroded in recent years. According to

some of these stakeholders, the United States may have to follow the lead

of the European community in selecting the types of new technologies that

will be used under free flight. For example, some stakeholders noted that

Europe is at least 3 years ahead of the United States in developing and

deploying the data link technology that will serve as a centerpiece for

implementing free flight. While several stakeholders noted that valuable

lessons may be learned from the Europeans’ work on data link, one

stakeholder stressed that it is important for the United States to position

itself so that it can make decisions about technology requirements that

best reflect the needs of U.S. operations.

FAA Needs to Integrate

Free Flight Technologies

Some FAA officials and stakeholders told us that the agency needs to

integrate free flight technologies with one another and into the operating

air traffic control system. This integration is expected to allow FAA and

users to fully exploit the capabilities of these technologies to help ensure

that promised improvements in safety, capacity, and efficiency are

Page 47 GAO/RCED-98-246 Free Flight Initiatives
Chapter 3 

FAA and the Aviation Community Face

Many Challenges in Implementing Free

Flight Cost-Effectively

realized. For example, as noted in chapter 2, FAA has new technologies that

are expected to improve the efficiency of operations at high altitudes,

close to the terminal, and on the ground. Because some of these

technologies have not been designed to work together, some stakeholders

and FAA officials contend that their potential benefits—e.g., allowing the

distance between aircraft to be safely reduced, when practical, throughout

a flight’s operation—will not be maximized unless they are integrated.

One airframe manufacturer noted that the key impediment to changing the

NAS is not new technology, but how to integrate that technology into an

operating NAS. As a result, care must be taken to help ensure that planned

changes in operations, procedures, and airspace usage will not adversely

affect safety and will meet users’ future needs. Another stakeholder noted

that integrating new technologies (and associated procedures) into the

present operating system is difficult because there are complex

interdependencies between the technologies currently being

used—making incremental changes to the system complex and the

consequences of introducing abrupt changes unpredictable. Stakeholders

have raised concerns that FAA does not have sufficient internal expertise to

complete integration tasks. FAA officials acknowledge that they do not

have the internal expertise or experience to do the avionics systems

integration work for Flight 2000 (now the Free Flight Operational

Enhancement Program); the agency plans to hire an integration contractor

to do this work. FAA believes that it has sufficient expertise to do the

remainder of the integration work required for free flight. However, to

enhance expertise within the agency, FAA has identified competencies

essential to efficiently manage complex acquisition programs and is

providing a variety of opportunities for staff to further develop their

expertise.

Airport Capacity Issues

Need Attention

Stakeholders questioned whether FAA is paying enough attention to

increasing airport capacity. Many stakeholders stressed that using free

flight in the en route environment may get aircraft to their destinations

sooner, but the planes may then be delayed by limits on airport surface

capacity, such as too few runways and gates. Several stakeholders also

stressed that poor weather conditions limit airports’ capacity and said that

more sophisticated technology is needed to predict hazardous weather

conditions so that airports’ capacity can be optimized. In June 1998, we

reported that FAA has not assigned weather information a high priority in

Page 48 GAO/RCED-98-246 Free Flight Initiatives
Chapter 3 

FAA and the Aviation Community Face

Many Challenges in Implementing Free

Flight Cost-Effectively

its plans for the NAS architecture.28 Because weather information is not

considered critical, research on weather systems is often among the first

to be cut—potentially jeopardizing mulityear studies of weather problems

affecting aviation. Given the significant impact of hazardous weather on

aviation safety and efficiency, improving the weather information available

to all users should be one of FAA’s top priorities. The agency is taking steps

to address its shortcomings in this area, and in fiscal year 1999, FAA is

elevating weather research as a funding priority.

28Aviation Safety: FAA Has Not Fully Implemented Weather-Related Recommendations,

(GAO/RCED-98-130, June 2, 1998).

Page 49 GAO/RCED-98-246 Free Flight Initiatives
Appendix I 

RTCA’s Free Flight Recommendations

On October 26, 1995, RTCA Task Force 3 issued a report29 detailing the

recommended actions and time frames for gradually implementing free

flight. These recommendations were divided into three

categories—(1) near term (1995 through 1997),30 (2) midterm (1998

through 2000),31 and (3) far term (2001 and beyond).32 The following are

the recommendations from this RTCA report. FAA identified 11

recommendations related to Free Flight Phase 1—these are shown in bold.

Near-Term

Recommendations,

1995-97

1. The Federal Aviation Administration (FAA), in cooperation with users,

must develop new procedures which use airplane Random

Navigation/Area Navigation (RNAV) capabilities to reduce congestion over

waypoints. Such procedures should be expedited for the top 50 airports.

2. Institute a process to quickly develop the standards, criteria,

procedures, and training programs necessary to expand implementation

procedures for use of area navigation equipment capabilities, including

vertical guidance, to increase capacity and operating efficiency in terminal

areas.

3. Review existing air traffic control (ATC) procedures to identify changes

for increased use of RNAV routes below Flight Level 180.

4. The planned expansion of the National Route Program (NRP)

should be continued.

5. Where appropriate, decrease 200 nautical mile radius restriction

for NRP filing.

6. Develop mechanisms to provide predeparture feedback to the

flight planners on potential impacts of requested flight plans,

changes to requested flight plans, and systems constraints causing

those changes.

29Final Report of RTCA Task Force 3: Free Flight Implementation, RTCA (Oct. 26, 1995). In Aug. 1996,

RTCA published a follow-on action plan that describes the initiatives needed to implement each of the

recommendations. See RTCA Action Plan (Aug. 15, 1996).

30With one exception, near-term action items are designated by number. The following

recommendation—listed as B—while not designated with a number, falls after recommendation 23.

Recommendation B states, Work with the user community to achieve consensus on the role and

timing of Automatic Dependent Surveillance-Broadcast [ADS-B] technology in delivering specific

near- and long-term benefits.

31Midterm action items are prefaced with MT.

32Far-term action items are prefaced with FT.

Page 50 GAO/RCED-98-246 Free Flight Initiatives
Appendix I 

RTCA’s Free Flight Recommendations

7. Implement rationing-by-schedule during ground delay programs.

8. Establish more flexible ground delay program procedures and

supporting decision support systems (DSS).

9. Establish a coordinated effort among military, FAA, and National

Airspace System (NAS) users to define the information and

capabilities necessary to improve civil use of Special Use Airspaces

(SUA) when not being utilized by DOD.

10. An operational trial in one or more SUA should be conducted to

demonstrate how improved information exchange on the status of

SUA can improve civil use of SUAs when not being utilized by DOD.

11. Develop and implement real-time SUA notification between DOD

and FAA, and between FAA and flight planners. A program plan is

needed in the near term.

12. Streamline the FAA certification process to reduce time and costs for

approval and fielding of new and emerging technologies.

13a. In collaboration with NAS users, the FAA should make a decision on the

initial air/ground data link to be implemented for domestic ATC

communications, navigation, and surveillance.

13b. The FAA should collaborate with the airspace users in the continued

development of oceanic data link (i.e., Satellite Voice and Data

Communications [SATCOM], High Frequency [HF] data link).

14. Improve telecommunication mechanisms to enhance the free flow of

information between users and the Traffic Flow Management (TFM) system

on a machine to machine basis.

15. Incorporate airline schedule updates (e.g., company delays and

cancellations) in FAA decision support systems and decision processes.

16. Enhance, if possible, or replace the current Air Traffic Management

(ATM) monitor/alert function, including, but not limited to, a means of

measuring controller workload and complexity.

17. Expedite the deployment of digital Automatic Terminal

Information Service (ATIS), automated taxi clearance and

Page 51 GAO/RCED-98-246 Free Flight Initiatives
Appendix I 

RTCA’s Free Flight Recommendations

expanded use of a standard taxi clearance as appended to the

Pre-Departure Clearance (PDC). Expedite expansion of PDC to

additional 27 sites. Evaluate expansion beyond the planned 57.

18. FAA should initiate the development of the standards for a cockpit

situational awareness display of traffic information.

19. Deploy a ground-based conflict probe in the near term to

accelerate the selection and development of a conflict probe with

automated planning aids to assist controllers in the identification

and resolution of conflicts.

20a. Expedite the implementation of the technologies and capabilities

(e.g., Center TRACON Automation System [CTAS]) necessary for improved

transition to, from, and operations in the terminal airspace, including the

ability to sequence and schedule aircraft arriving on unstructured routes.

20b. Move mature elements of CTAS forward out of research and

development (R&D) into implementation ensuring adherence to free flight

principles.

21. In cooperation with airspace users, investigate the technical feasibility,

safety, cost, and benefits of using Global Positioning System (GPS) Wide

Area Augmentation System (WAAS) as an en route vertical reference, e.g.,

for Reduced Vertical Separation Minima (RVSM).

22. The FAA should support the Meteorological Data Collection and

Reporting System (MDCRS) to enhance the quality and quantity of

real-time aircraft-reported weather information.

23. Develop the capability—starting with existing capabilities—to generate

more accurate forecasts on convective weather for use in flight and

operational planning.

24. Develop methodology and tools to measure and predict dynamic

density.

25. Develop, evaluate, and implement TFM capability for a cooperative

exchange of information amongst the users and the FAA that will enable

user involvement in the FAA’s TFM decision making process.

Page 52 GAO/RCED-98-246 Free Flight Initiatives
Appendix I 

RTCA’s Free Flight Recommendations

25a. Building on existing activities, such as Traffic Flow

Management-Architecture and Requirements Team (TFM-ART) and

FAA-Airline Data Exchange (FADE), and related programs, the FAA and

users must determine the details of an improved user-TFM interaction.

25b. In concert with the users, FAA must aggressively pursue the testing

and implementation of development programs, and/or more flexible

procedures, aimed at supporting the cooperative exchange of real-time

data and information between the users and TFM system. Start now by

developing TFM scenarios with the users that substitute controlled time of

arrival (CTA) instead of the currently employed departure clearance time.

Evaluate this soon at one airport.

26. FAA and users should establish procedures for aircraft to aircraft

separation when separation responsibility may be transferred to the

aircraft by the air traffic service provider on a case by case basis.

27. Implement precision missed approaches and precision simultaneous

approaches and departures.

28. Investigate the possibility of increasing runway acceptance by

permitting two aircraft to occupy the runway at the same time.

29. Additional expansion of the NRP below Flight Level 290 should

be explored. Accelerate modeling and analysis efforts needed to

facilitate the continued expansion of the NRP.

30. Issue an Advance Notice of Proposed Rulemaking regarding

implementation of domestic reduced vertical separation minima (RVSM)

above Flight Level 290.

31. The FAA should determine the requirements for reduced en route

horizontal separation standards, including surveillance performance.

32. Begin rulemaking to remove the 250 knots below 10,000 feet

restriction in Class B airspace.

33. The FAA should study human perceptions and responses associated

with the time and distance buffers that separate aircraft (protected and

alert zones). FAA must determine that proposed changes in separation rules

and maneuver limits do not increase perceived hazards, statistical risks,

and experienced discomfort. FAA must show that the proposed changes

Page 53 GAO/RCED-98-246 Free Flight Initiatives
Appendix I 

RTCA’s Free Flight Recommendations

will make the present system more efficient, safe, or economical before

implementation.

34. Real-time human-in-the-loop simulations should be conducted to

systematically study controller and pilot behaviors, interactions, and

effects within NAS environments that represent dynamic densities and

sector configurations anticipated for free flight.

35. Reemphasize the role of the Airport Improvement Program in

increasing airport capacity.

Midterm

Recommendations,

1998-2000

MT1. Increase FAA Air-Route Traffic Control Center (ARTCC) decision

support capabilities as soon as possible to include the total U.S.

navigational database.

MT2. Accelerate and expand programs to support GPS/WAAS as a primary

navigation system (e.g., airport surveys, update FAA orders, precision

approaches at majority of airports in the contiguous United States, Hawaii,

Southern Alaska, and the Caribbean).

MT3. Ensure that requirements for Standard Terminal Automation

Replacement System (STARS) for Terminal Radar Approach Controls

(TRACONs) and Display System Replacement (DSR) for ARTCCs be modified

to include a provision, i.e., a “hook” for receiving, processing, and

displaying Automatic Dependent Surveillance-Broadcast (ADS-B) signals

and data link.

MT4. Develop and implement technology for the dissemination of weather

products and flight information to the cockpit. Development of FIS

application standards should be done in coordination with cockpit traffic

display standards.

MT5. FAA must develop and deploy dynamic/adaptive sectors as a means to

facilitate free flight operations.

MT6. Initiate the development of, and implement, ADS to support user

preferred trajectories in non radar areas; includes ground infrastructure

(communications and automation) and user equipage.

Page 54 GAO/RCED-98-246 Free Flight Initiatives
Appendix I 

RTCA’s Free Flight Recommendations

Far-Term

Recommendations,

2001 and Beyond

FT1. Expand the number of airports to receive surface surveillance

capability.

FT2. The FAA should define a surveillance architecture and infrastructure

for en route and terminal airspace incorporating both dependent and

independent surveillance elements. The architecture must meet the

requirements for reduced separation standards, improved coverage, and

lower-cost maintenance determined by other related studies and

investigations, and should facilitate enhancing both near-term surveillance

capabilities and those required for mature free flight.

FT3. Determine Local Area Augmentation System (LAAS) capability to

enable increased availability of Category I, II, III approaches and

implement LAAS, as appropriate.

Page 55 GAO/RCED-98-246 Free Flight Initiatives
Appendix II 

Status of Selected RTCA Recommendations

Related to Free Flight Phase 1, as of

July 1998

RECOMMENDATION INITIATIVE STATUSa

4. The planned expansion of the National

Route Program (NRP) should be continued.

a. FAA Notice 7110.147, National Route

Program, dated 12/20/95, has been

revised to create a more aggressive

expansion form.

Completed. Effective 2/26/97 Notice will be

incorporated into FAA Order 7210.3

chapter 18.

b. Conduct ATC system impact analysis

and modeling.

Completed by MITRE-CAASD.

c. NRP expansion to FL 290. Completed 10/96.

d. Conduct postexpansion workload

analysis to identify issues and lessons

learned from planned expansion to FL 290.

Database for tracking issues concerning

NRP developed. Ongoing historical data

collection.

RECOMMENDATION INITIATIVE STATUSa

5. Where appropriate, decrease

200-nautical-mile- radius restriction for NRP

filing.

a. Examine feasibility of reducing the

200-nautical-mile radius using existing

modeling and analysis capabilities.

Analysis should address issues such as

workload and redesign of national

airspace. Initial simulation analysis

completed. Additional simulation and

Human in the Loop (HITL) analyses are

planned.

MITRE Corporation did some initial

analysis on reduction of 200-nautical-mile

restriction in increments of 50 nautical

miles. The results were not especially

useful because the modeling was

designed to set a baseline and did not

reflect realistic expectations of increased

airline participation. Further consideration

indicated this was not a realistic approach

because (1) the ingress/egress mileage

would vary greatly from airport to airport

and (2) programming of airline databases

to account for airport variations would be

cumbersome and time consuming.

b. Develop procedures for use of

Instrument Departure Procedures (DP) and

Standard Terminal Arrival Routes (STAR)

for filing a Standard Instrument Departure

(SID) to the NRP to a STAR at destination.

Development of the DP/STAR goal to allow

users to file Instrument Departure

Procedures transitions to join an NRP

route, and exit an NRP route via the

transition of a Standard Terminal Arrival

Route.

c. Begin testing and evaluation of

DP/STAR egress/ingress program at

airport city pairs as agreed upon by FAA

and industry working groups.

A notification under the provisions of the

collective bargaining agreement was

issued to NATCA on 2/10/97.

d.Implement DP/STAR egress/ingress

program nationally. Identify and

disseminate ingress/egress points inside

or outside 200-nautical-mile radius (those

that do not have DPs/STARs).

•On 4/1/98, a committee consisting of

National Air Traffic Controllers Association

(NATCA), ATO-100/200, and the Airline

Transport Association convened to outline

the DP/STAR project and to provide

national oversight. The National Business

Aircraft Association and Regional Aircraft

Association were invited to attend and will

continue to be invited to participate on the

committee.

(continued)

Page 56 GAO/RCED-98-246 Free Flight Initiatives
Appendix II 

Status of Selected RTCA Recommendations

Related to Free Flight Phase 1, as of

July 1998

RECOMMENDATION INITIATIVE STATUSa

•Regions and facilities will be tasked to

review DP/STAR transitions to area airports

to evaluate applicability to the DP/STAR

goal.

•Procedures for implementing the

DP/STAR program have been developed

and agreed upon by FAA and industry

work group members.

•Initial list of select cities has been

developed consisting of 24 DPs and 11

STARs.

•Coordination with NATCA on

implementation of initial cities list

completed 3/25/98.

•Initial list of DPs/STARs changed. New list

includes Denver, Albuquerque,

Minneapolis/St. Paul, and Salt Lake City. A

total of 14 DPs with 73 transitions, and 19

STARS with 40 transitions approved for

implementation.

•All transitions of each DP/STAR may not

be available/published because of facility

procedural constraints.

•Advisory Circular 90-91B and FAA Notice

7210.468 defining program requirements

published 4/15/98.

•Workgroup met 7/8/98-7/9/98 to develop

and agree upon next airports for

implementation later in 1998.

•Program name changed to “Departure

Procedure/Standard Terminal Arrival Route

Transition to the National Route Program.”

Airports that do not have DP/STAR routes

are not likely to be the primary

departure/destination points of the users.

After the DP/STAR program is

implemented at most major sites, attention

can be given to address those airports and

determine a reasonable distance

expectation for users to join a published

route. (Published route indicating a jet or

victor airway, as opposed to published

preferred Instrument Flight Rules (IFR)

route.) The latter are navigational aids.

Page 57 GAO/RCED-98-246 Free Flight Initiatives
Appendix II 

Status of Selected RTCA Recommendations

Related to Free Flight Phase 1, as of

July 1998

RECOMMENDATION INITIATIVE STATUSa

6. Develop mechanisms to provide

predeparture feedback to the flight planners

on potential impact of requested flight plans,

changes to requested flight plans, and

system constraints causing those changes.

a. RTCA Special Committee (SC) 169

Working Group 5 to define detailed and

prioritized near- and longer-term needs

and benefits estimate, including

requirements for a centralized database

identifying NAS status for flight planning.

Data exchange mechanism in place.

Traffic Flow Management (TFM) R&D

activity with industry has indicated that this

capability will evolve naturally at a later

stage of data exchange development.

Therefore, work on this recommendation is

being deferred until the appropriate time.

b. FAA will identify, with industry, near-term

procedural changes to increase

information available on system constraints

for flight planning, including general

aviation requirements.

c. Working Group 5 will develop

operational concept automated

predeparture feedback and flight plan

amendments for operations via direct

interface between the Airline Operations

Centers (AOC) and traffic management.

d. Define interface requirements between

AOAS/DOTS.

RECOMMENDATION INITIATIVE STATUSa

9. Establish a coordinated effort among

military, FAA, and NAS users to define the

information and capabilities necessary to

improve civil use of SUAs when not being

utilized by DOD.

a. Establish working group of military, FAA,

other government agencies, NATCA, and

users to determine specific information

requirements concerning SUA availability

and time frames for notification of

availability.

Additional activities/site visits the SUA

work group has been involved with: Delta

Airlines Operations Center (AOC),

American Airlines AOC, Jacksonville Air

Route Traffic Control Center (ARTCC), Fort

Worth ARTCC, Jacksonville Fleet Area

Control and Surveillance Facility, Fort

Worth Joint Reserve Base, White Sands

Missile Range, USS John C. Stennis

aircraft carrier, Gainesville Automated

Flight Service Station (AFSS), Fort Worth

AFSS, Gulf of Mexico Users Meeting, and

the Government/Industry Aeronautical

Charting Forum.

b. Implement FAA system of tracking SUA

availability (SAMS).

SAMS has been installed at all ARTCCs,

Honolulu and San Juan Combined

Center-Military Radar Approach Control

(RAPCON), Fayetteville, High Desert, and

Pensacola TRACONs, and Fort Worth

AFSS.

(continued)

Page 58 GAO/RCED-98-246 Free Flight Initiatives
Appendix II 

Status of Selected RTCA Recommendations

Related to Free Flight Phase 1, as of

July 1998

RECOMMENDATION INITIATIVE STATUSa

c. FAA will develop rules and procedures

to support identified requirements for

supporting improved civil access to SUA.

The procedures to disseminate SUA

schedules developed in Action Item 10a

have been replicated at Jacksonville

ARTCC and New York ARTCC for warning

area information, and Albuquerque ARTCC

for White Sands Missile Range information.

The Industry/Government Aeronautical

Charting Forum is reviewing the work

group’s request to chart frequencies for

SUA information on aeronautical charts

used by general aviation pilots, and to

display Air Traffic Control Assigned

Airspace on pertinent aeronautical charts.

d. DOD SUA scheduling system to provide

electronic schedules to FAA systems by

1998.

Negotiations are ongoing between FAA

and DOD; tentative initial operating

capability is 8/98.

e. Define and implement interface between

SAMS and Enhanced Traffic Management

System (ETMS)/Notices to Airman

(NOTAM)/other systems to allow for

transfer of SUA information to users.

Remaining software development

requirements include, but are not limited

to, analysis reports and interfaces with

Enhanced Traffic Management System,

Military Airspace Management System,

and distribution of the data to Flight

Service Stations. ADTN2000 was selected

as the telecommunications network for the

SAMS v3.0 system. Installation of the

network began in 9/96. Currently there are

six sites remaining that are awaiting

connectivity or line installation. In addition,

Internet Protocol (IP) addresses have not

been tested which provide connectivity to

the main server site at the Air Traffic

Control System Command Center

(ATCSCC) and the other sites.

(continued)

Page 59 GAO/RCED-98-246 Free Flight Initiatives
Appendix II 

Status of Selected RTCA Recommendations

Related to Free Flight Phase 1, as of

July 1998

RECOMMENDATION INITIATIVE STATUSa

f. FAA will compare available capabilities

with identified requirements to determine if

additional infrastructure development (e.g.,

air/ground communication) is required.

Cost/benefit of additional development will

be assessed.

Free Flight working group was formed to

address real-time SUA management as it

applies to free flight. The group consists of

representatives from FAA, commercial

aviation, general aviation, DOD,

Department of the Interior, (DOI), and

NATCA. The group met and

teleconferenced several times since their

initial meeting 8/8/96, to address items 9,

10, and 11, including an on-site visit to

Edwards AFB/R-2508 Complex. The

following points have been made: (1) DOD

policy of returning SUA back to the

controlling agency (FAA) when not in use

is considered fundamentally sound and

supported by all concerned. The

implementation of this policy was observed

at Edwards AFB. (2) Non-DOD NAS users

(commercial and general aviation)

reiterated that they seek access to SUA

when that airspace is not in use. (3)

Non-DOD NAS users understand that their

request to gain access to SUA, when that

airspace is inactive, requires coordination

and approval through FAA. (4) DOD

requires flexible scheduling to accomplish

its mission. Rigid scheduling requirements

would not accommodate the many

variables that could affect the mission, i.e.,

weather, telemetry/instrumentation, aircraft

availability, etc.

(5) Non-DOD NAS users indicated that

they require SUA status information from

FAA as soon as FAA knows it. This

includes air traffic control assigned

airspace (ATCAA) and its charting.

(6) Information dissemination to non-DOD

NAS users, by FAA, appears to be a major

issue where most follow-on action must be

focused. FAA acknowledges its

responsibility for information sharing and

those inefficiencies in information

dissemination that need to be addressed,

i.e., who gets the information, how do they

get it, when do they get it, and where do

they get it?

(continued)

Page 60 GAO/RCED-98-246 Free Flight Initiatives
Appendix II 

Status of Selected RTCA Recommendations

Related to Free Flight Phase 1, as of

July 1998

RECOMMENDATION INITIATIVE STATUSa

g. Establish a measurement capability to

track SUA volume, utilization, and

management.

Free Flight working group was formed to

address real-time SUA management as it

applies to free flight. The group consists of

representatives from FAA, commercial

aviation, general aviation, DOD, DOI, and

NATCA. The group met and

teleconferenced several times since their

initial meeting 8/8/96, to address items 9,

10, and 11, including an on-site visit to

Edwards AFB/R-2508 Complex. The

following points have been made: (1)

DOD’s policy of returning SUA back to the

controlling agency (FAA) when not in use

is considered fundamentally sound and is

supported by all concerned. The

implementation of this policy was observed

at Edwards AFB. (2) Non-DOD NAS users

(commercial and general aviation)

reiterated that they seek access to SUA

when that airspace is not in use. (3)

Non-DOD NAS users understand that their

request to gain access to SUA, when that

airspace is inactive, requires coordination

and approval through FAA. 

(4) DOD requires flexible scheduling to

accomplish its mission. Rigid scheduling

requirements would not accommodate the

many variables that could affect the

mission, i.e., weather,

telemetry/instrumentation, aircraft

availability, etc. (5) Non-DOD NAS users

indicated that they require SUA status

information from FAA as soon as FAA

knows it. (6) Information dissemination to

non-DOD NAS users, by FAA, appears to

be the major issue where most follow-on

action must be focused. FAA

acknowledges its responsibility for

information sharing and those

inefficiencies in information dissemination

that need to be addressed, i.e., who gets

the information, how do they get it, when

do they get it, and where do they get it?

Page 61 GAO/RCED-98-246 Free Flight Initiatives
Appendix II 

Status of Selected RTCA Recommendations

Related to Free Flight Phase 1, as of

July 1998

RECOMMENDATION INITIATIVE STATUSa

10. An operational trial in one or more SUA

should be conducted to demonstrate how

improved information exchange on the status

of SUA can improve civil use of SUAs when

not being utilized by DOD.

a. Technical working group (formed in

Rec. 9a) identifies one or more SUAs for

operational trials of data sharing with

existing capabilities.

The working group recommended an

operational trial at the R-2508 Complex

(Edwards AFB). SUA information was

disseminated by Oakland ARTCC via the

ETMS mail system to air carriers with no

disruption to DOD operations. The trial was

conducted in 2/97 and 3/97 and required

the cooperation and coordination of FAA’s

Western-Pacific Region Air Traffic Division,

R-2508 Complex Control Board, Oakland

ARTCC, High Desert TRACON, Los

Angeles ARTCC, and the user community.

A second trial commenced on 12/20/97

between New York metropolitan (JFK,

LGA, EWR) airports and Orlando

International Airport. Aircraft are being

routed offshore and transitioned, if

feasible, through the warning areas on a

real-time basis.

b. Identify FAA and DOD lead for this

effort, and identify priority status of this

effort.

Completed.

c. FAA and DOD collect benefits and

operational issues during trials.

FAA, DOD, and other users collected

information during the operational trial at

the R-2508 Complex. One airline stated it

was saving $30,000 per month through

fuel loading decisions for the trial, while

there was no impact on DOD’s operations.

The procedure was implemented on a

permanent basis at the R-2508 Complex.

Data are still being collected for the

Orlando International Airport trial.

d. Results (costs and benefits) of

operational trial will be fed into procedure

and infrastructure development activities in

Rec. 9.

The procedures for the R-2508 Complex

were implemented at Jacksonville and

New York ARTCCs for warning area

information, and at Albuquerque ARTCC

for the White Sands Complex of SUA.

Data are still being collected for the

Jacksonville trial.

(continued)

Page 62 GAO/RCED-98-246 Free Flight Initiatives
Appendix II 

Status of Selected RTCA Recommendations

Related to Free Flight Phase 1, as of

July 1998

RECOMMENDATION INITIATIVE STATUSa

e. FAA/DOD agreement on national

procedures.

The following points were made:

(1) The R-2508 Complex dynamically

accommodates civil in-flight requests for

flight within the R-2508 airspace.

(2) Information sharing between DOD and

FAA in the R-2508 Complex is

accomplished very efficiently through a

variety of electronic exchanges, as well as

being physically collocated in the

TRACON facility. 

(3) Information sharing between FAA and

Non-DOD NAS users normally occurred on

a tactical, real-time basis. 

(4) Filing and approval of more preferred

routing through the R-2508 Complex in a

southeast direction, i.e., J-110, with

Oakland Center has been a problem for

the airlines. Filing and approval of more

preferred routing in the northwest direction

through R-2508 via J-110 has not been a

problem. 

(5) Participants are tasked to compile a list

of SUAs that they believe would be

candidates for another operational trial.

Another on-site visit has been scheduled

tentatively for the North Florida area. 

(6) The operational trial at the R-2508

Complex will be incorporated into standard

operating procedures. 

(7) An attempt will be made to transfer this

strategy to provide air carriers with

information about the availability of certain

airspace.

Page 63 GAO/RCED-98-246 Free Flight Initiatives
Appendix II 

Status of Selected RTCA Recommendations

Related to Free Flight Phase 1, as of

July 1998

RECOMMENDATION INITIATIVE STATUSa

11. Develop and implement real-time SUA

notification between DOD and FAA, and

between FAA and flight planners. A program

plan is needed in the near term.

a. The joint team (formed in Rec. 9a) will

assess the need for real-time SUA

notifications and will develop a program

plan to reflect needed changes in systems,

procedures, and training to implement

real-time exchanges of schedule

information.

The work group in Rec. 9 wanted FAA to

provide the information to users as it is

received.

b. Examine needed internal and external

FAA infrastructure changes to enable

real-time SUA notification, such as an

interface between SAMS and the Host.

The Host Replacement Mission Need

Statement has been approved by FAA.

The entry and display of SUA information

will be available to the air traffic controller.

RECOMMENDATION INITIATIVE STATUSa

17. Expedite the deployment of Digital

Automatic Terminal Information Service

(D-ATIS), automated taxi clearance, and

expanded use of a standard taxi clearance as

appended to the Pre-Departure Clearance

(PDC). Expedite expansion of PDC to

additional 27 sites. Evaluate expansion

beyond the planned 57.

a. Deliver all 57 tower data link sites for

PDC and D-ATIS.

PDC is operational at all 57 sites. D-ATIS is

operational at 49 sites, and the other 8 are

awaiting completion of D-ATIS local

refresher training. D-ATIS operation

expected at remaining sites by 5/98.

b. Complete Detroit demonstration of taxi

route delivery.

Four-month demonstration under way, to

be followed by a 1-month evaluation,

expected to be completed by 6/98.

c. Publish charted standard taxi routes for

national implementation.

The activity is postponed until benefits

have been assessed on the basis of the

Detroit demonstrations’ results.

d. Free Flight Steering Committee identifies

additional sites for tower data link services,

conducts cost/benefit analyses, and

makes recommendations to FAA.

No candidate sites for expansion have

been identified.

e. Notify Free Flight Steering Committee on

decision for additional sites.

No candidate sites for expansion have

been identified.

Page 64 GAO/RCED-98-246 Free Flight Initiatives
Appendix II 

Status of Selected RTCA Recommendations

Related to Free Flight Phase 1, as of

July 1998

RECOMMENDATION INITIATIVE STATUSa

19. Deploy a ground-based conflict probe in

the near term to accelerate the selection and

development of a conflict probe with

automated planning aids to assist controllers

in the identification and resolution of conflicts.

a. Deploy mature components of present

conflict probe and automated planning

research at selected field facilities for

concept development and evaluation.

(Move from laboratory to field evaluation.)

Efforts under way that may lead to

operationally deployable capabilities

include:

User Request Evaluation Tool (URET) at

Indianapolis and Memphis (ZID and ZME)

Centers,

Prediction Resolution Advisory Tool (PRAT)

at Boston (ZBW) Center, 

User Preferred Routing Conflict Probe

(UPR) at Denver (ZDV) Center, and

Free Flight Evaluation Work Station at

Kansas City (ZKC) Center.

The evaluation of the PRAT system at ZBW

was completed in 9/96. PRAT is a source

of potential requirements for the follow-on

Initial Conflict Probe (ICP) capability. Full

evaluation of PRAT was handicapped by

issues associated with proprietary

software. The field evaluation of the URET

operational prototype system began in

2/96 at ZID and 6/97 at ZME and remains

in progress. Daily use (8 hours per day, 5

days per week) of URET began at ZID in

9/97 and at ZME in 11/97 using the

baseline software version D2.1. Evaluation

of the Interfacility Automation (IFA) version

D3.0 between ZID and ZME began in

10/97 and was completed in 2/98. D3.0

(without IFA) was implemented as the daily

use software in 2/98. Daily use was

expanded to 12 hours per day in 3/98.

D3R3, a component of D3a1, to correct

Red Route Processing and Airport Arrival

Stream filtering, was delivered in 2/98 and

evaluated in 3/98 and 4/98. D3R3 became

the daily use software in 5/98. The

remainder of the D3a1 (now D3a since the

D3a2 delivery was eliminated) was to be

delivered in 7/98.

A preliminary Systems Specification and

algorithmic definition documents for key

algorithmic areas have been developed on

the basis of URET evaluations done to date

and evaluation reports.

The initial technology transfer process from

MITRE/CAASD to FAA and its development

contractors for DSR ICP was completed in

late 1997. Technology transfers continue

on the additional functionality. A MITRE

Technical Assessment Report positively

assessed the URET operational concept

and also identified the need for substantial

re-architecture and re-coding of the

software for full scale DSR ICP

development. URET is presently regarded

as a source of requirements and

algorithms for both ICP and Future Conflict

Probe (FCP).

(continued)

Page 65 GAO/RCED-98-246 Free Flight Initiatives
Appendix II 

Status of Selected RTCA Recommendations

Related to Free Flight Phase 1, as of

July 1998

RECOMMENDATION INITIATIVE STATUSa

An initial field trial of the UPR Transition

Airspace Tool was conducted as a

research activity at ZDV in 9/96.

Simulations using the UPR Transition

Airspace Tool with controllers were

conducted in 11/96. A “shadow mode”

(office area) version of the UPR Transition

Airspace Tool was installed at ZDV in

12/96.

A full field evaluation of the UPR Transition

Airspace Tool was completed by NASA at

Denver in 9/97. A process for technology

transfer of the UPR Transition Airspace

Tool additions to CTAS Build 2 was

initiated in 5/97. The UPR Transition

Airspace Tool is viewed as a source of

requirements and reusable components

for the FCP initiative.

The Free Flight Evaluation System (FFES)

is a MITRE/CAASD research activity at

ZKC looking at long-term requirements for

automation to support free flight. No

detailed FAA explanation of FFES is

planned. FFES is in the concept

exploration stage. FFES is viewed as a

source of requirements for the FCP

capability and later enhancements.

b. FAA, with users and NATCA, will

develop an incremental plan and concept

for deploying components of conflict probe

prototypes to improve functionality. This

plan will identify procedural and regulatory

changes and agreements that will be

needed to address issues of operational

deployment.

FAA’s development strategy for ICP has

been focused on the URET operational

prototype, user acceptance, and display

refinement. A URET implementation

viability assessment was completed in

12/96. MITRE/CAASD is continuing to

refine detailed technical requirements for

key areas; these areas include Interfacility

Automation (IFA) and conflict probability

prediction.

Options being explored for the ICP

implementation included re-architecting

URET as an integral part of DSR to achieve

the initial DSR ICP requirements and

specifications.

(continued)

Page 66 GAO/RCED-98-246 Free Flight Initiatives
Appendix II 

Status of Selected RTCA Recommendations

Related to Free Flight Phase 1, as of

July 1998

RECOMMENDATION INITIATIVE STATUSa

A formal investment decision (JRC) on fullscale implementation of DSR ICP was

scheduled for 3/98 but postponed

because of the Core Capabilities Limited

Development Free Flight Phase 1 (CCLD

FFP1) initiative. Data collected for the JRC

include cost, benefits, schedule, and

technical requirements baseline data. This

includes a benefits assessment conducted

at the ZID DySim in 1/98.

FAA has been analyzing a

recommendation by RTCA/ATA for

deploying URET to five additional sites.

The proposed ARTCCs are Cleveland,

Atlanta, Chicago, Memphis, Kansas City,

Washington, and Indianapolis. The

proposal includes options for URET as a

stand-alone system similar to the ZID and

ZME installations or integrated with DSR.

Either would include functionality

equivalent to URET D3.1. ATO and NATCA

have indicated that a single display,

keyboard, and pointing device would be

required, necessitating an integrated

architecture. Deployment schedules

continue to evolve to support funding

profiles and DSR schedules. The initial

daily use of CCLD URET (Build 1) is

estimated for 11/01 and Build 2 for 10/02.

The benefits analyses of CCLD will drive

FAA’s decisions for deployment of an ICP

or ERATMDST. Currently, the intention is to

deploy the initial FCP 12 months after FSD

of DSR ICP.

Activities leading to the development of a

specification for the FCP (integrated

ICP/DA/TMA) system was initiated in 4/97,

with the initial draft specification to be

released in 3/99. Operational evaluation of

this system will evolve from a basic

capability of ICP being provided to the

R-Side and Traffic Management Advisor to

the D-Side, up to and including integration

and similar capabilities available to both Dand R-Sides.

(continued)

Page 67 GAO/RCED-98-246 Free Flight Initiatives
Appendix II 

Status of Selected RTCA Recommendations

Related to Free Flight Phase 1, as of

July 1998

RECOMMENDATION INITIATIVE STATUSa

c. With users and NATCA, FAA will

evaluate limited deployment prototypes

and will determine if, where, and when it

will be possible to implement components

of those prototypes to provide benefits

before DSR implementation. (Move from

prototype to local operational deployment.)

FAA’s development strategy for ICP has

been focused on the URET operational

prototype. The initial URET technology

transfer from MITRE/CAASD to FAA and its

contractors is complete. MITRE/CAASD is

continuing to refine the detailed technical

requirements for key areas of the ICP

capability; these areas include Interfacility

Automation (IFA), automated coordination,

and conflict probability prediction.

The implementation of ICP was planned as

the first Pre-Planned Product Improvement

(PPPI) for DSR, 6 months following FSD. A

formal investment decision (JRC) was

planned for full-scale implementation of

ICP by 3/98 but was deferred to

accommodate FFP1 planning. Cost,

benefit, schedule, and technical

requirements baseline data are being

collected to support a decision for ICP.

Most recent planning calls for URET CCLD

as part of the FFP1 initiative. With the

establishment of a System Program Office

(SPO) to manage the CCLD FFP1, the

direction after URET CCLD Build 2 is still

evolving. Options would include a

nationally deployed DSR ICP or FCP.

Preliminary benefits analyses are based on

limited experimentation at Indianapolis

ARTCC. Baseline measures for ATM with

and without automation decision support

tools are being developed.

The URET operational prototype was

installed at all sectors at ZID and ZME by

1/98. It was expanded from 8 hours a day,

5 days per week, to 12 hours per day. It is

intended to be available 16 hours a day, 5

days per week. The initial goal of 16 by 7

will be dependent on funding availability.

Daily use of URET began at ZID in 9/97

and ZME in 11/97.

d. Implement components of conflict probe

prototypes to provide benefit before DSR

implementation. (Move from local

deployment to national deployment.)

FAA’s deployment strategy for ICP has

been focused on the URET prototype. User

acceptance and display refinement are

more advanced for the URET system than

other candidate systems. A URET

implementation viability assessment was

completed in 12/96. MITRE/CAASD is

continuing to refine the detailed technical

requirements for key areas of the ICP

capability; these areas include IFA and

conflict probability prediction.

(continued)

Page 68 GAO/RCED-98-246 Free Flight Initiatives
Appendix II 

Status of Selected RTCA Recommendations

Related to Free Flight Phase 1, as of

July 1998

RECOMMENDATION INITIATIVE STATUSa

Options explored for the ICP

implementation were using URET software,

re-architecting URET as an integral part of

DSR, or re-using portions of various

systems and prototypes (e.g., CTAS, UPR,

URET) to achieve DSR ICP requirements.

The decision was made to use URET.

In 3/98, FAA began evaluation of an

RTCA/ATA recommendation to deploy

URET “as is” to five additional centers. The

stand-alone URET will continue to be used

at ZID and ZME and because of the DSR

schedule, will not be deployed to

additional ARTCCs. The CCLD FFP1

initiative plans to deploy URET CCLD to

seven ARTCCs to permit a robust

evaluation of user benefits and support of

free flight.

A formal investment decision (JRC) on the

full-scale implementation of ACD-D was

scheduled for 3/98 but deferred pending a

recommended position on FFP1. Data

being collected for the JRC include costs,

benefits, schedules, and technical

requirements baseline information.

The URET operational prototype was

installed “as is” to all sectors at ZID and

ZME in 1/98. It expanded to 12 hours, 5

days per week, in 4/98 and is to evolve to

16 hours per day, 5 days a week. Daily use

began at ZID in 9/97 and ZME in 11/97.

Daily use in at least three areas was to be

achieved at both ZID and ZME by 9/98. As

of 6/98, all sectors at ZID are approved for

use, and four of five areas at ZME have

been approved. Well over half the

controllers have been trained and the

remainder will be trained by 12/31/98. A

critical functionality, two-way Host

interface, is scheduled for delivery to the

WJHTC in 10/98 and the ARTCCs in 12/98.

The daily-use URET system will continue to

be used to gather data to support

operational development of the FSD ICP

system. The URET evaluation systems will

also support benefits data collection as

well as controller evaluation of CHI and

functionality.

Page 69 GAO/RCED-98-246 Free Flight Initiatives
Appendix II 

Status of Selected RTCA Recommendations

Related to Free Flight Phase 1, as of

July 1998

RECOMMENDATION INITIATIVE STATUSa

22. FAA should support the Meteorological

Data Collection and Reporting System

(MDCRS) to enhance the quality and quantity

of real-time aircraft-reported weather

information.

a. National Weather Service (NWS) review

of processing options for aircraft

meteorological data.

The NWS review of processing options is

complete. The ARINC Corporation will

continue to decode the ACARS data from

the airlines and process it into the MDCRS

format. The data are processed on a

platform called the ATS server, which

replaced the TANDEM processor.

Deployment was completed 7/97.

b. Memorandum of agreement on cost

sharing between FAA and NWS.

The establishment of a memorandum of

agreement on cost sharing between FAA

and NWS has not been formalized.

However, under the current ARINC

contract FAA and NWS have equally

shared the cost of developing the new ATS

server. The ATS server processes and

sends MDCRS data via communication

circuits to the NWS gateway.

c. Industry-sponsored user education

program to solicit participation by more

aircraft.

ARINC continues to sponsor user

education programs to solicit participation

from airlines. Two additional airlines are

expected to provide meteorological data in

1998.

RECOMMENDATION INITIATIVE STATUS

29. Additional expansion of the NRP below FL

290 should be explored. Accelerate modeling

and analysis efforts needed to facilitate NRP’s

continued expansion.

a. Form a working group consisting of

industry, NATCA, and FAA to identify

methods to accommodate user-preferred

routing below FL 290.

Working groups have been formed and are

meeting.

b. Conduct modeling and simulation to

identify impact of increased user-preferred

routing below FL 290. Evaluate airspace

capacity and demand, sector design,

controller workload, communication, and

information requirements.

MITRE/CAASD study complete.

c. Build on FAA/NATCA composite direct

route document with fixes for direct routing

at lower altitudes.

Deferred until enhancements to program

are completed in RTCA recommendation 5.

Page 70 GAO/RCED-98-246 Free Flight Initiatives
Appendix II 

Status of Selected RTCA Recommendations

Related to Free Flight Phase 1, as of

July 1998

RECOMMENDATION INITIATIVE STATUSa

32. Begin rule-making to remove the 250-knot

speed limit for departing aircraft at elevations

below 10,000 feet in Class B airspace.

a. Using existing laboratory simulation

capabilities, evaluate removing the

250-knot restriction, assessing capacity,

environmental (noise), safety and workload

issues.

•Initial simulations

The field test at Houston has provided

partial validation of the operational

feasibility of modifying or removing the

250-knot speed limit for departing aircraft.

The results of the preliminary evaluation

are, for the most part, positive. Even where

metrics indicated some effects on the

areas examined, the results may be

considered positive in the sense that the

test did not produce any conclusive

indication that modifying the speed

restriction is unworkable.

b. Field test removal of restriction at

selected airports.

The field test at Houston Intercontinental

began 6/26/97. On the basis of preliminary

evaluation, FAA is recommending that the

test be extended to a second site.

c. Remove restriction incrementally. Pending completion of field testing.

aThe status of each initiative is as described by the responsible FAA official.

Source: FAA.

Page 71 GAO/RCED-98-246 Free Flight Initiatives
Appendix III 

Proposed Operational Capabilities for Flight

2000, Renamed the Free Flight Operational

Enhancement Program

This table describes the proposed operational capabilities contained in the

roadmap for the revised Flight 2000 program that was developed by RTCA

and was submitted in September 1998 to FAA for approval. A decision is

expected in fall 1998. Over 70 operational capabilities were reviewed using

four criteria1

 and 9 were selected as essential for the successful evolution

of the NAS. The revised demonstration is tentatively planned for

implementation between 1999 and 2004. Each of the nine capabilities is

described below, including the expected operational benefits and the

locations where deployment is planned.

Operational capability Description Expected operational benefits Locationsa

Flight Information Service (FIS) for

Special Use Airspace (SUA) Status,

Weather, Wind-Shear, Notice to

Airmen (NOTAM), Pilot Reports

(PIREP)

Use FIS to provide pilots and

controllers with current and

forecasted weather and

weather-related information as

well as the status of SUAs; the

information will be displayed

graphically to the pilot

•Increased availability of flight

services

•Increased timeliness and quality of

data on weather and system status

•Increased access to airspace

•Reduced flight times and distances

Alaska

Cost-Effective Controlled Flight Into

Terrain (CFIT) Avoidance Through

Graphical Position Display

Provide a cost-effective terrain

database and display in the

cockpit

•Increased pilot awareness of

surrounding terrain

•Reduction in the CFIT rate

•Increased access to low-altitude

airspace where terrain-imposed

restrictions exist

Alaska

Improved Terminal Operations in

Low-Visibility Conditions

Use Automatic Dependent

Surveillance-Broadcast (ADS-B)b,

Cockpit Display of Traffic

Information (CDTI), and Traffic

Information Service (TIS) during

low-visibility approach operations

so that the flight crew will be

better able to identify and judge

the distance and speed of the

aircraft they are following

•Improved ability of crew to

accomplish approaches at lower

minimums

•Ability of flight crew to maintain

better spacing during Visual Flight

Rules (VFR) and Instrument Flight

Rules (IFR) approaches

•Increased access to airports

•Increased arrival rates

•Reduced arrival and departure

delays

•Increased predictability of arrival

times

•Increased flexibility of arrival

scheduling

Ohio Valley

Enhanced See and Avoid Provide traffic information

electronically to the cockpit using

ADS-B, and CDTI, and TIS or

Traffic Information

Service-Broadcast (TIS-B)

•Improved ability of pilots to

maintain awareness of surrounding

traffic, even in instrument

meteorological conditions

•Increased safety

Ohio Valley, Alaska

(continued)

1

In general, under these criteria (1) industry and FAA must address all aspects of modernization to be

successful in moving toward free flight; (2) expected benefits are the major reason for implementing a

given capability; (3) the capability does not interfere with or slow down any near-term activities; and

(4) the risks associated with operational capabilities that require the integration of multiple

communication, navigation, and surveillance technologies should be addressed.

Page 72 GAO/RCED-98-246 Free Flight Initiatives
Appendix III 

Proposed Operational Capabilities for Flight

2000, Renamed the Free Flight Operational

Enhancement Program

Operational capability Description Expected operational benefits Locationsa

Enhanced Operations for En Route

Air-to-Air

Evaluate the use of Cockpit

Display of Traffic Information

(CDTI) and Automatic Dependent

Surveillance-Broadcast (ADS-B)

to allow delegation of separation

authority to the cockpit

•Increased access to airspace

•Reduced flight delays

and distances flown

•Increased predictability of flight

times and distances flown

•Increased flexibility in routes flown

Ohio Valley, Alaska

Improved Surface Navigation Equip aircraft and ground

vehicles with a moving-map

display that allows pilots and

vehicle operators to “see” all other

traffic

•Improved ability of pilots and

vehicle operators to navigate the

airport surface, including the ability

of pilots to taxi using augmented

Global Positioning System (GPS)

navigation and maps and, in

extremely low-visibility conditions,

using Local Area Augmentation

System (LAAS)

•Reduced runway incursion incidents

•Reduced taxi delays

•Increased predictability of taxi times

Ohio Valley, Alaska

Enhanced Airport Surface

Surveillance for the Controller

Equip aircraft and ground

vehicles in the airport movement

area with ADS-B using

augmented GPS-derived positions

•Enables local and ground

controllers to monitor the positions

and speeds of all vehicles on the

airport surface, even in low-visibility

conditions

•Reduced runway incursion incidents

•Reduced taxi delays

•Reduced arrival delays

•Increased predictability of taxi times

•Increased departure/arrival rates

Ohio Valley, Alaska

Automatic Dependent

Surveillance-Broadcast (ADS-B) for

Surveillance in Non-Radar Airspace

•Use ADS-B to provide additional

surveillance coverage and fill

gaps in radar coverage

•Examine how ADS-B could

eventually replace some radars

•Improved controller ability to

provide separation services and

reduced reliance on procedural

separation

•Increased access to airspace

•Increased arrival and departure

rates

•Reduced flight delays

and distances flown

•Increased predictability of flight

times and distances flown

•Reduced deviations from the

intended route

•Increased flexibility in the routes

flown

•Increased safety

Alaska

Establish ADS-B Based Separation

Standards

•Integrate ADS-B data with radar

and conflict alert to determine if

separation standards can be

reduced

•Ultimately integrate ADS-B with

advanced decision support

automation

•Increased efficiency

•Maintained or increased safety

Alaska

(Table notes on next page)

Page 73 GAO/RCED-98-246 Free Flight Initiatives
Appendix III 

Proposed Operational Capabilities for Flight

2000, Renamed the Free Flight Operational

Enhancement Program

aSelected sites for demonstrations in the Ohio Valley include Memphis, Tennessee; Wilmington,

Ohio; Louisville, Kentucky; Scott Air Force Base (Belleville, Illinois); and Nashville, Tennessee.

Additionally, Alaska was chosen as a second location primarily for the demonstration of the safety

aspects associated with the selected operational capabilities.

bADS-B avionics periodically broadcast aircraft position information derived from GPS

augmentations to enable other aircraft and ground systems to perform surveillance of equipped

aircraft on the airport surface or in terminal and en route phases of flight.

Page 74 GAO/RCED-98-246 Free Flight Initiatives
Appendix IV 

Expert Advisors on Free Flight

Dr. R. John Hansman, Jr., Professor of Aeronautics and Astronautics,

Massachusetts Institute of Technology.

Dr. Wesley L. Harris, Professor of Aeronautics and Astronautics,

Massachusetts Institute of Technology.

Page 75 GAO/RCED-98-246 Free Flight Initiatives
Appendix V 

Major Contributors to This Report

Resources,

Community, and

Economic

Development

Division, Washington,

D.C.

John H. Anderson, Jr.

Monique C. Austin

Beverly Norwood Dulaney

Elizabeth R. Eisenstadt

David B. Goldstein

Belva M. Martin

Office of General

Counsel

David K. Hooper

(348025) Page 76 GAO/RCED-98-246 Free Flight Initiatives
Ordering Information

The first copy of each GAO report and testimony is free.

Additional copies are $2 each. Orders should be sent to the

following address, accompanied by a check or money order

made out to the Superintendent of Documents, when

necessary. VISA and MasterCard credit cards are accepted, also.

Orders for 100 or more copies to be mailed to a single address

are discounted 25 percent.

Orders by mail:

U.S. General Accounting Office

P.O. Box 37050

Washington, DC 20013

or visit:

Room 1100

700 4th St. NW (corner of 4th and G Sts. NW)

U.S. General Accounting Office

Washington, DC

Orders may also be placed by calling (202) 512-6000 

or by using fax number (202) 512-6061, or TDD (202) 512-2537.

Each day, GAO issues a list of newly available reports and

testimony. To receive facsimile copies of the daily list or any

list from the past 30 days, please call (202) 512-6000 using a

touchtone phone. A recorded menu will provide information on

how to obtain these lists.

For information on how to access GAO reports on the INTERNET,

send an e-mail message with "info" in the body to:

info@www.gao.gov

or visit GAO’s World Wide Web Home Page at:

http://www.gao.gov

PRINTED ON RECYCLED PAPER
United States

General Accounting Office

Washington, D.C. 20548-0001

Official Business

Penalty for Private Use $300

Address Correction Requested

Bulk Rate

Postage & Fees Paid

GAO

Permit No. G100