a

GAO

United States Government Accountability Office

Report to Congressional Requesters

June 2005 NATIONAL AIRSPACE 

SYSTEM

FAA Has Made 

Progress but 

Continues to Face 

Challenges in 

Acquiring Major Air 

Traffic Control 

Systems

GAO-05-331
What GAO Found

United States Government Accountability Office

Why GAO Did This Study

Highlights

Accountability Integrity Reliability

www.gao.gov/cgi-bin/getrpt?GAO-05-331.

To view the full product, including the scope 

and methodology, click on the link above. 

For more information, contact Gerald L. 

Dillingham, (202) 512-2834, 

dillinghamg@gao.gov. 

Highlights of GAO-05-331, a report to 

congressional requesters 

June 2005

NATIONAL AIRSPACE SYSTEM

FAA Has Made Progress but Continues to 

Face Challenges in Acquiring Major Air 

Traffic Control Systems 

The ATO met its acquisition goal for fiscal year 2004. However, prior to the 

establishment of the ATO, FAA had experienced more than two decades of 

cost, schedule, and/or performance shortfalls in acquiring major systems 

under its ATC modernization program. For example, 13 of the 16 major 

system acquisitions that we reviewed in detail have experienced cost, 

schedule, and/or performance shortfalls when assessed against their original 

milestones. These 13 system acquisitions experienced total cost growth from 

$1.1 million to about $1.5 billion; schedule extensions ranging from 1 to 13 

years; and performance shortfalls, including safety problems. We found that 

one or more of four factors—funding, requirements growth and/or unplanned 

work, stakeholder involvement, and software complexity—have contributed 

to these legacy challenges. While FAA met its recent acquisition goal, it is 

important to note that this goal is based on updated program milestones and 

cost targets for system acquisitions, not those set at their inception. 

Consequently, they do not provide a consistent benchmark for assessing 

progress over time. Also, as indicators of annual progress, they cannot be 

used in isolation to measure progress over the life of an acquisition. 

Although additional steps are warranted, FAA has taken some positive steps 

to address key legacy challenges it has had with acquiring major systems 

under the modernization program. For example, the ATO has cut funding for 

some major systems that were not meeting their goals and is reassessing all 

capital investments to help ensure that priority systems receive needed 

funding. The ATO has improved its management of software-intensive 

acquisitions and information technology investments and begun to more 

actively involve stakeholders. As we recommended, the ATO plans to 

establish an overall policy to apply its process improvement model to all 

software-intensive acquisitions. However, additional steps could be taken to 

improve its management of system acquisitions. For example, the ATO could 

use a knowledge-based approach to managing system acquisitions, 

characteristic of best commercial practices, to help avoid cost, schedule, and 

performance problems. 

The ATO will also be challenged to modernize the ATC system under 

constrained budget targets, which would provide FAA with about $2 billion 

less than it planned to spend through 2009. To fund its major system 

acquisitions and remain within these targets, the ATO has eliminated planned 

funding to start new projects and substantially reduced planned funding for 

other areas. However, when forwarding its budget submission for review by 

senior officials at FAA, DOT, the Office of Management and Budget, and 

Congress, the ATO provides no detail on the impact of the planned funding 

reductions on ATC modernization and related activities to modernize the 

NAS. Our work shows that the ATO should provide these decisionmakers 

with detailed information in its budget submissions about the impact of 

funding decisions on modernization efforts. Without this type of information, 

decision-makers lack important details when considering FAA’s annual 

budget submissions.

The Federal Aviation 

Administration’s (FAA) 

multibillion-dollar effort to 

modernize the nation’s air traffic 

control (ATC) system has suffered 

from cost, schedule, and/or 

performance shortfalls in its 

system acquisitions for more than 

two decades and has been on our 

list of high risk programs since 

1995. FAA’s performance-based 

Air Traffic Organization (ATO) was 

created in February 2004, in part, to 

address these legacy challenges. 

In this report, GAO examined (1) 

FAA’s experience in meeting cost, 

schedule, and performance targets 

for major ATC system acquisitions; 

(2) steps taken to address legacy 

problems with the program and 

additional steps needed; and (3) the 

potential impact of the constrained 

federal budget on this program. 

What GAO Recommends

GAO recommends that the 

Secretary of Transportation direct 

FAA to provide detailed 

information to Congress about the 

impact of planned funding cuts on 

the agency’s ability to modernize 

the ATC system, and the National 

Airspace System (NAS). 

In commenting on a draft of this 

report, the Department of 

Transportation (DOT), FAA, and 

ATO said they generally agreed 

with the report. They did not 

comment on the recommendation.
Page i GAO-05-331 National Airspace System

Contents

Letter 1

Results in Brief 4

Background 7

FAA Has Had Difficulty Meeting Cost, Schedule, and/or Performance 

Targets for Major System Acquisitions, but Made Progress in 

Fiscal Year 2004 11

FAA Has Taken Some Positive Steps to Address Key Legacy 

Challenges, but Additional Steps Are Warranted to Reduce Risk 

and Strengthen Oversight 24

A Constrained Budgetary Environment Could Further Challenge the 

ATO’s Efforts to Modernize the ATC System 30

Conclusions 33

Recommendation for Executive Action 34

Agency Comments 34

Appendixes

Appendix I: Background and Status of FAA’s 16 Major System 

Acquisitions We Reviewed in Detail 36

Airport Surface Detection Equipment–Model X (ASDE-X) 36

Airport Surveillance Radar Model-11 (ASR-11) 38

Air Traffic Control Radar Beacon Interrogator-Replacement 

(ATCBI-6) 40

Advanced Technologies and Oceanic Procedures (ATOP) 42

Controller-Pilot Data Link Communications (CPDLC) 45

En Route Communications Gateway (ECG) 47

En Route Automation Modernization (ERAM) 49

Free Flight Phase 2 (FFP2) 50

FAA Telecommunications Infrastructure (FTI) 52

Integrated Terminal Weather System (ITWS) 54

Local Area Augmentation System (LAAS) 56

Next Generation Air-to-Ground Communication (NEXCOM) 59

NAS Infrastructure Management System—Phase 2 (NIMS-2) 61

Operational and Supportability Implementation System (OASIS) 63

Standard Terminal Automation Replacement System (STARS) 66

Wide Area Augmentation System (WAAS) 69

Appendix II: Information on the 39 Additional Systems under the ATC 

Modernization Program 72

Appendix III: Objectives, Scope, and Methodology 80

Appendix IV: GAO Contact and Staff Acknowledgments 83
Contents

Page ii GAO-05-331 National Airspace System

Tables Table 1: Changes in Cost and Schedule Targets for 16 Major ATC 

System Acquisitions 12

Table 2: Four Key Factors Contributing to Cost Growth, Schedule 

Extensions, and/or Performance Problems for 13 ATC 

System Acquisitions 16

Table 3: Description and Status of Nine Additional Major ATC 

System Acquisitions with Cost, Schedule, and 

Performance Targets 22

Table 4: Cost and Schedule Information for Nine Additional Major 

Systems under the ATC Modernization Program 72

Table 5: Cost and Schedule Information for the 30 

Buy-It-by-the-Pound Systems under the ATC 

Modernization Program 74

Figures Figure 1: Sixteen Major Systems We Examined in Detail by Phase 

of Flight 10

Figure 2: ASDE-X Screen Depicting an Airport Layout with Active 

Aircraft Targets 36

Figure 3: Changes to ASDE-X Schedule and Cost Targets 37

Figure 4: ASR-11 Equipment 38

Figure 5: Changes to ASR-11 Schedule and Cost Targets 39

Figure 6: ATCBI-6 Screen Display Depicting All 

Transponder-Equipped Aircraft 40

Figure 7: Changes to ATCBI-6 Cost and Schedule Targets 41

Figure 8: ATOP Equipment Reporting Aircraft Position 

Information 42

Figure 9: Changes to ATOP Schedule and Cost Targets 43

Figure 10: CPDLC Text Message on an Aircraft Display 45

Figure 11: Changes to CPDLC Schedule and Cost Targets 46

Figure 12: ECG Maintenance Workstation Display 47

Figure 13: Changes to ECG Schedule and Cost Targets 48

Figure 14: Changes to ERAM Schedule and Cost Targets 49

Figure 15: Free Flight Phase 2 User Request Evaluation Tool 50

Figure 16: Changes to FFP2 Schedule and Cost Targets 51

Figure 17: FTI Primary Network Operations Control Center 52

Figure 18: Changes to FTI Schedule and Cost Targets 53

Figure 19: ITWS Situation Display 54

Figure 20: Changes to ITWS Schedule and Cost Targets 55

Figure 21: Key Components of LAAS 56

Figure 22: Changes to LAAS Schedule and Cost Targets 57

Figure 23: Multimode Digital Radio 59
Contents

Page iii GAO-05-331 National Airspace System

Figure 24: Changes to NEXCOM Schedule and Cost Targets 60

Figure 25: NIMS Infrastructure 61

Figure 26: Changes to NIMS–Phase 2 Schedule and Cost Targets 62

Figure 27: OASIS Dual Screen Display 63

Figure 28: Changes to OASIS Schedule and Cost Estimates 64

Figure 29: STARS Controller Workstation 66

Figure 30: Changes to STARS Schedule and Cost Targets 67

Figure 31: Key Components of WAAS 69

Figure 32: Change to WAAS Schedule and Cost Targets 70

Abbreviations

ACE-IDS Automated Surface Observing System Controller Equipment 

Information Display System

ADL Aeronautical Data Link 

ADS-B Automatic Dependent Surveillance-Broadcast 

AFSS Automated Flight Service Stations 

ALSIP Approach Lighting System Improvement Program

AMS Acquisition Management System

ARCSCC FAA Air Traffic Control System Command Center 

ARTCC Air Route Traffic Control Centers 

ARTS Automated Radar Terminal System 

ASWON Aviation Surface Weather Observation Network 

ASDE-X Airport Surface Detection Equipment – Model X

ASOS Automated Surface Observing System

ASR-9 Airport Surveillance Radar – Model 9

ASR-11 Airport Surveillance Radar – Model 11

ATC Air Traffic Control

ATCBI-6 Air Traffic Control Beacon Interrogator Replacement 

ATCT Air Traffic Control Towers 

ATO Air Traffic Organization

ATOP Advanced Technologies and Oceanic Procedures

AWOS Automated Weather Observing System

AWSS Automated Weather Sensors Systems

C3 Command, Control, and Communications

CARTS Common Automated Radar Terminal System

CCS Command Center Conference Control System

CDM Collaborative Decision Making 

CFE Communications Facilities Enhancements

CMMI Capability Maturity Model Integration

CNS Communications, Navigation, and Surveillance 
Contents

Page iv GAO-05-331 National Airspace System

CIWS Corridor Integrated Weather System 

COTS Commercial-Off-the-Shelf 

CPDLC Controller-Pilot Data Link Communications

CTS Critical Telecommunications Support 

DME Distance Measuring Equipment

DOD Department of Defense

DSP Departure Spacing Program 

E-Scan Electronic Scan 

ECG En Route Communication Gateway 

ERAM En Route Automation Modernization

ETVS Enhanced Terminal Voice Switches

FAA Federal Aviation Administration

FFP2 Free Flight Phase 2 

FIS Flight Information Service 

FISDL Flight Information Service Data Link 

FTI FAA Telecommunications Infrastructure 

GAO U.S. Government Accountability Office

GNSS Global Navigation Surveillance Systems

HAATS Houston Area Air Traffic System 

HOCSR HOST/Oceanic Computer System Replacement 

IATS Initial Academy Training System 

ICAO International Civil Aviation Organization 

iCMM integrated Capability Maturity Model

ILS Instrument Landing System

IOC Initial Operating Capability

IT Information Technology

ITIM Information Technology Investment Management 

ITWS Integrated Terminal Weather System

JRC Joint Resources Council

LAAS Local Area Augmentation System

LRR Long-range Radar 

NAS National Airspace System

NDI Non-Developmental Item 

NASR National Airspace System Resources

NEXCOM Next Generation Air-to-Ground Communication System

NEXRAD Next Generation Weather Radar

NIMS-2 National Airspace System Infrastructure Management 

System-Phase 2

NOTAM Notice to Airmen 

NTSB National Transportation Safety Board

NWS National Weather Service 

OASIS Operational and Supportability Implementation System
Contents

Page v GAO-05-331 National Airspace System

OMB Office of Management and Budget

ORD Operational Readiness Date

PRM Precision Runway Monitor

RFI Radio Frequency Interference

RIRP Runway Incursion Reduction Program

RTCA Radio Technical Commission for Aeronautics

RVR Runway Visual Range

SAWS Stand-alone Weather Sensors 

SF-21 Safe Flight 21 Program 

SLEP Service Life Extension Program 

STARS Standard Terminal Automation Replacement System

TDLS Tower Data Link Services

TFM-I Traffic Flow Management-Infrastructure

TMA Traffic Management Advisor

UHF Ultra High Frequency 

URET User Request Evaluation Tool

VOR Very High Frequency Omni-directional Range

VORTAC Very High Frequency Omni-directional Collocated with Tactical 

Air Navigation 

VRRP Voice Recorder Replacement Program

VSCS Voice Switching and Control System 

WAAS Wide Area Augmentation System

WMSCR Weather Message Switching Center Replacement

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Page 1 GAO-05-331 National Airspace System

United States Government Accountability Office

Washington, D.C. 20548

A

June 10, 2005 Letr

Congressional Requesters

In 1981, the Federal Aviation Administration (FAA) began what it initially 

envisioned as a 10-year modernization program to upgrade and replace the 

National Airspace System’s (NAS) facilities and equipment to meet 

projected increases in traffic volumes, enhance the system’s margin of 

safety, and increase the efficiency of the air traffic control (ATC) system—a 

principal component of the NAS. To date, FAA has spent $43.5 billion for its 

NAS modernization effort1

 and plans to spend an additional $9.6 billion 

through fiscal year 2009, primarily to upgrade and replace ATC systems and 

facilities.2

 For more than two decades, ATC system acquisitions under the 

NAS modernization program3 have experienced significant cost growth, 

schedule delays, and performance problems. As a result, the ATC 

modernization program has been on our list of high-risk programs since 

1995. To improve FAA’s management of the modernization program, 

Congress, in 1995, gave the agency acquisition and human capital 

flexibilities,4

 which FAA has largely implemented.

In 2000, Congress and the administration took further steps to improve the 

modernization program’s management. Through legislation and an 

executive order, they laid the foundation for, among other things, a 

performance-based organization to manage FAA’s ATC investments and 

operations and a chief operating officer to lead it. In response, FAA hired a 

chief operating officer in August 2003 and created the Air Traffic

1

For purposes of this report, “NAS modernization” refers to ATC facilities, equipment, and 

related expenses.

2

The estimates are presented in then-year dollars, which means that they represent the 

nominal dollar sum of the estimated spending in different years. To estimate future-year 

spending, FAA incorporates assumptions on inflation developed by the Office of 

Management and Budget (OMB). 

3

This report, as well as our work for more than two decades on FAA’s ATC modernization 

program, has assessed progress for major ATC system acquisitions based on the cost, 

schedule, and performance goals set at the inception of each program. 

4

Department of Transportation Appropriations Act, Pub. L. 104-50, § 348 (1995).
Page 2 GAO-05-331 National Airspace System

Organization (ATO)5 in February 2004. The ATO inherited the decades-long 

legacy of cost, schedule, and/or performance problems with major ATC 

system acquisitions and at the same time received $400 million less for 

fiscal year 2005 than it had planned to spend for ATC modernization. In 

addition, projected funding levels from the administration are about $2 

billion less than FAA had planned to spend for fiscal years 2005 through 

2009. 

The ATC modernization program is critical to meeting future air traffic 

safety, capacity, and efficiency needs. FAA reported that U.S. airlines 

carried nearly 690 million passengers in 2004 and that it expects the 

number of passengers to reach 1 billion by 2015. According to FAA, the 

agency has spent about 58 percent, or $25.1 billion, of the $43.5 billion total 

for NAS modernization on system acquisitions designed to replace or 

upgrade various ATC systems. 

In light of past problems with and continuing concerns about funding 

major ATC system acquisitions under the ATC modernization program, you 

asked us to examine (1) FAA’s experience in meeting cost, schedule, and/or 

performance targets for major system acquisitions under its ATC 

modernization program; (2) the steps FAA has taken to address longstanding challenges with the ATC modernization program and additional 

steps that are needed; and (3) the potential effects of the constrained 

budget environment on FAA’s ability to modernize the ATC system. To 

address these objectives, we reviewed in detail 16 of the 55 system 

acquisitions6

 under the ATC modernization program, primarily by 

interviewing FAA officials and obtaining and analyzing key acquisition

5

Wendell H. Ford Aviation Investment and Reform Act for the 21st Century, Pub. L. 106-181, 

§ 303 (2000); E.O.13180. Under the executive order, part of the ATO’s purpose is to “develop 

methods to accelerate air traffic control modernization and to improve aviation safety 

related to air traffic control.” 

6

According to FAA officials, the number of system acquisitions in the ATC modernization 

program can vary annually, when Congress earmarks funds for a specific system acquisition. 

As of March 2005, the number of system acquisitions under the program was 55. 
Page 3 GAO-05-331 National Airspace System

documents.7 We selected these 16 systems in July 2004, when this review 

was still a part of our broader work on FAA’s efforts to modernize the

NAS.8,9 Specifically, we selected the 16 ATC system acquisitions with the 

largest life-cycle costs that met the following criteria: each system had cost, 

schedule, and performance targets; was discussed in prior GAO and 

Department of Transportation Inspector General (DOT IG) reports, had not 

been fully implemented or deployed by 2004, and received funding in 2004. 

We reviewed this list with FAA officials to ensure that we did not exclude 

any significant system. In fiscal year 2005, these 16 major ATC system 

acquisitions account for about 36 percent of FAA’s facilities and equipment 

budget.10 (See app. I for additional information on these 16 systems.) We 

also collected information on the remaining 39 system acquisitions under 

this program, which account for about 19 percent of FAA’s facilities and 

equipment account for fiscal year 2005.11 (See app. II for additional 

information on these 39 systems.) In addition, we reviewed past GAO and 

DOT IG reports. We interviewed FAA officials within the recently created 

ATO and collected and analyzed the documents they provided. We also 

interviewed officials with the Aircraft Owners and Pilots Association, Air 

Transport Association, Department of Defense (DOD), National Air Traffic

7

At the time of our audit, FAA planned to deploy 64 Operational and Supportability 

Implementation Systems (OASIS) to automated flight service stations by 2005. However, 

after deploying 19 such systems in 2004, FAA discontinued the system’s deployment, 

pending a decision about whether to contract out the operation of automated flight service 

stations. In February 2005, FAA awarded a contract to Lockheed Martin to operate these 

stations.

8

Our methodology for selecting the 16 system acquisitions to review in detail was based on 

the fiscal year 2004 appropriation for FAA’s facilities and equipment budget, which was 

available when the engagement was designed. However, to make the report as current as 

possible, we have used fiscal year 2005 funding levels where appropriate, including the 

status sheets for each of the 16 systems in appendix I. See app. III for additional information 

on our methodology.

9

Our review of FAA’s NAS modernization efforts will be issued later this year.

10FAA does not have a formal definition of “major” systems under its Acquisition 

Management System; however, agency officials told us that if a system acquisition has a 

formally approved baseline, we could consider it “major.” Using this definition, 25 of the 55 

system acquisitions under the ATC modernization program are major. 

11The remaining 45 percent of the facilities and equipment budget for fiscal year 2005 will be 

spent on facilities, mission support, and personnel-related activities. 
Page 4 GAO-05-331 National Airspace System

Controllers Association, and RTCA.12 Furthermore, we convened a panel of 

international aviation experts.13 Our review did not focus on FAA’s efforts 

to modernize its airports and other agency facilities. We conducted our 

review from November 2004 through May 2005 in accordance with 

generally accepted government auditing standards. (See app. III for 

additional information on our objectives, scope, and methodology.)

Results in Brief The ATO has shown progress during its first year of operation by meeting 

its acquisition goal for fiscal year 2004. However, for more than two 

decades, FAA has experienced cost growth, schedule extensions, and/or 

performance problems in acquiring major systems under its ATC 

modernization program and has been on our list of high-risk programs 

since 1995.14 Since their inception, 13 of the 16 major system acquisitions 

that we reviewed in detail for this engagement have experienced cost, 

schedule, and/or performance shortfalls when assessed against their 

original baselines or performance targets. Specifically, the total cost for 

these 13 major system acquisitions ranged from $1.1 million to about 

$1.5 billion over their original cost targets. In addition, these 13 system 

acquisitions also experienced schedule extensions that ranged from 1 to 13 

years15 over their original schedule targets. Furthermore, several of these 

13 system acquisitions experienced performance shortfalls related to 

12Organized in 1935 and once called the Radio Technical Commission for Aeronautics, RTCA 

is today known just by its acronym. RTCA is a private, not-for-profit corporation that 

develops consensus-based performance standards for ATC systems. RTCA serves as a 

federal advisory committee, and its recommendations are the basis for a number of FAA’s 

policy, program, and regulatory decisions.

13GAO, Experts’ Views on Improving the U.S. Air Traffic Control Modernization Program, 

GAO-05-333SP (Washington, D.C.: April 2005). 

14GAO, High-Risk Series: An Update, GAO-05-207 (Washington, D.C.: January 2005); GAO, 

Air Traffic Control: FAA Needs to Ensure Better Coordination When Approving Air 

Traffic Control Systems, GAO-05-11 (Washington, D.C.: Nov. 17, 2004); GAO, Air Traffic 

Control: FAA’s Acquisition Management Has Improved, but Policies and Oversight Need 

Strengthening to Help Ensure Results, GAO-05-23 (Washington, D.C.: Nov. 12, 2004); GAO, 

Information Technology: FAA Has Many Investment Management Capabilities in Place, 

but More Oversight of Operational Systems Is Needed, GAO-04-822 (Washington, D.C.: Aug. 

20, 2004); and GAO, Air Traffic Control: System Management Capabilities Improved, but 

More Can Be Done to Institutionalize Improvements, GAO-04-901 (Washington, D.C.: Aug. 

20, 2004). 

15Schedule extensions were calculated based on the date FAA plans to deploy the last 

system.
Page 5 GAO-05-331 National Airspace System

safety. Our work indicates that one or more of the following four factors 

have contributed to the legacy challenges FAA has experienced in meeting 

system acquisitions’ cost, schedule, and/or performance targets: (1) 

receiving funding for acquisitions at lower levels than called for in agency 

planning documents, (2) adding requirements and/or unplanned work, (3) 

not sufficiently involving stakeholders throughout system development, 

and (4) underestimating the complexity of software development. Three of 

the major 16 ATC system acquisitions we reviewed in detail are currently 

operating within their original cost, schedule, and performance targets, 

despite challenges that are symptomatic of past problems. To its credit, the 

ATO has reported that it met its annual acquisition performance goal for 

fiscal year 2004: to meet 80 percent of designated milestones and maintain 

80 percent of critical program costs within 10 percent of the budget as 

published in its Capital Investment Plan. However, in our opinion, having 

and meeting such performance goals is commendable, but it is important to 

note that these goals are updated program milestones and cost targets, not 

those set at the program’s inception.16 Consequently, they do not provide a 

consistent benchmark for assessing progress over time. Moreover, as 

indicators of annual progress, the goals cannot be used in isolation to 

measure progress in meeting cost and schedule targets over the life of an 

acquisition. Finally, given the problems FAA has had in acquiring major 

ATC systems for over two decades, it is too soon to tell whether meeting 

these annual performance goals will ultimately improve the agency’s ability 

to deliver system acquisitions as promised.

FAA has taken a number of positive steps, primarily through the ATO, to 

address key legacy challenges it has had with acquiring major systems 

under its ATC modernization program; however, additional steps are 

warranted to reduce risk and strengthen oversight. Some of the positive 

steps taken directly address the four factors we identified as contributing 

to cost, schedule, and/or performance problems, while others support 

more general efforts to improve the modernization program’s management. 

For example, the ATO has demonstrated a willingness to cut some major 

acquisitions that are not meeting their performance targets, even after 

investments of significant resources, and is reassessing all of its capital 

investments to help ensure that high-priority system acquisitions receive 

needed funding. The ATO has also improved its management of information 

16Our statements about cost, schedule, and/or performance in this report and in our past 

reports are based on the original targets that FAA established and approved at the start of its 

acquisition programs.
Page 6 GAO-05-331 National Airspace System

technology investments and software-intensive acquisitions; these efforts 

are positive steps toward minimizing growth in requirements and 

unplanned work and better assessing the complexity of software 

development. For example, on a number of software-intensive acquisition 

projects, the ATO has applied a process improvement model that resulted 

in positive outcomes such as enhanced productivity and greater ability to 

predict schedules and resources. As we recommended, FAA plans to 

institutionalize the use of this model by establishing a policy to define the 

ATO’s expectations for process improvements and a plan to address and 

coordinate process improvement activities throughout the organization.17

The ATO has also begun to include stakeholders in all phases of system 

development, so that they can provide input in response to technical or 

financial developments. However, we have identified additional steps that 

are needed to reduce risk and strengthen oversight. For example, we found 

that the ATO does not use a knowledge-based approach to system 

acquisitions, characteristic of best commercial practices for managing 

commercial and DOD product developments, which would help avoid cost, 

schedule, and/or performance problems.18 We recommended, among other 

things, that FAA take several actions to more closely align its acquisition 

management system with commercial best practices. FAA said that our 

recommendations would be helpful to them as they continue to refine this 

system. Continued improvement and management attention will be crucial 

if the organization is to succeed in addressing key legacy challenges.19

The current constrained budget environment, which includes lower future 

budget targets than those of recent years, poses further challenges to the 

ATO as it attempts to modernize the ATC system. FAA plans to spend 

$4.4 billion from fiscal year 2005 through fiscal year 2009 to fund key 

modernization efforts; however, this funding level is about $2 billion less 

than the agency had expected in appropriations for this 5-year period. To 

fund its major system acquisitions while remaining within the budget 

targets, the ATO has eliminated planned funding to start new projects and 

reduced planned funding for other areas. However, when forwarding its 

budget submission for review by senior FAA, DOT, and OMB officials and 

by Congress, the ATO provides no detail on the impact of the planned 

funding reductions on ATC modernization and related activities to 

17GAO-04-901.

18GAO-05-23.

19GAO-05-207.
Page 7 GAO-05-331 National Airspace System

modernize the NAS. Our work shows that the ATO should provide these 

officials and Congress with detailed information in its budget submissions 

about the impact of reduced budgets on both ATC and NAS modernization. 

To do so, the ATO should explicitly identify the trade-offs it is making to 

reach budget targets, highlighting those programs slated for increased 

funding and those slated for reduced funding. Without this type of 

information, decision-makers lack important details when considering 

FAA’s annual budget submissions. We are recommending that FAA provide 

this information to Congress annually. 

In commenting on draft of this report, DOT, FAA, and ATO generally agreed 

with the report and provided technical comments, which we incorporated 

as appropriate. The FAA officials said they are continuing to consider our 

recommendation and indicated they would provide a written statement 

required by 31 U.S.C. 720.20

Background The mission of FAA, as a DOT agency, is to provide the safest, most 

efficient aerospace system in the world. To fulfill its mission, FAA must rely 

on an extensive use of technology, including many software-intensive 

systems. FAA constantly relies on the adequacy and reliability of the 

nation’s ATC system, which comprises a vast network of radars; automated 

data processing, navigation, and communications equipment; and ATC 

facilities.21 Through this system, FAA provides services such as controlling 

takeoffs and landings and managing the flow of traffic between airports.

FAA is organized into several staff support offices and five lines of 

business, which include Airports, Aviation Safety, Commercial Space 

2031 U.S.C. § 720 requires, in part, that agencies report the actions taken on our 

recommendation to the Senate Committee on Homeland Security and Governmental Affairs 

and to the House Committee on Government Reform not later than 60 days from the date of 

the report.

21FAA uses three types of facilities to control traffic: airport towers, terminal radar approach 

control facilities, and en route centers. Airport towers direct traffic on the ground, before 

landing, and after takeoff within 5 nautical miles of the airport and about 3,000 feet above 

the airport. Terminal radar approach control facilities sequence and separate aircraft as they 

approach and leave airports, beginning about 5 nautical miles and ending about 50 nautical 

miles from the airport and generally up to 10,000 feet above the ground. Air route traffic 

control centers, called en route centers, control aircraft in transit and during approaches to 

some airports, generally controlling air space that extends above 18,000 feet for commercial 

aircraft. 
Page 8 GAO-05-331 National Airspace System

Transportation, the Office of Security and Hazardous Materials, and the 

newly formed ATO.22 The ATO was formed in February 2004 to, among 

other things, improve the provision of air traffic services and accelerate 

modernization efforts. To create the ATO, FAA combined its Research and 

Acquisition and Air Traffic Services into one performance-based 

organization, bringing together those who acquire systems and those who 

use them, respectively. The ATO is led by FAA’s chief operating officer, 

consists of 10 service units,23 and has 36,000 of FAA’s 48,000 employees.

The ATO is the principal FAA organizational unit responsible for acquiring 

ATC systems through the use of the agency’s Acquisition Management 

System (AMS). Because FAA formerly contended that some of its 

modernization problems were caused by federal acquisition regulations, 

Congress enacted legislation in November 1995 that exempted the agency 

from most federal procurement laws and regulations and directed FAA to 

develop and implement a new acquisition management system that would 

address the unique needs of the agency. In April 1996, FAA implemented 

AMS. AMS was intended to reduce the time and cost of fielding new system 

acquisitions by introducing (1) a new investment system that spans the life 

cycle of an acquisition, (2) a new procurement system that provides 

flexibility in selecting and managing contractors, and (3) organizational 

and human capital reforms that support the new acquisition system. 

AMS provides high-level acquisition policy and guidance for selecting and 

controlling ATC system acquisitions through all phases of the acquisition 

life cycle, which is organized into a series of phases and decision points 

that include (1) mission analysis, (2) investment analysis, (3) solution 

implementation, and (4) in-service management. To select system 

acquisitions, FAA has two processes--mission analysis and investment 

analysis–that together constitute a set of policies and procedures, as well 

as guidance, that enhance the agency’s ability to screen system acquisitions 

submitted for funding. Also through these two processes, FAA assesses and 

ranks each system acquisition according to its relative costs, benefits, 

22Executive Order 13180 created the ATO. The executive order was later amended by 

Executive Order 13264, which removed the description of air traffic services as an 

“inherently governmental function.”

23The 10 service units that make up the ATO include Safety, Communications, Operations 

Planning, Finance, Acquisition and Business Services, En Route and Oceanic Services, 

Terminal Services, Flight Services, System Operations Services, and Technical Operations 

Services. 
Page 9 GAO-05-331 National Airspace System

risks, and contribution to FAA’s mission; a senior, corporate-level decisionmaking group then selects system acquisitions for funding. After a system 

acquisition has been selected, FAA officials are required to formally 

establish the life-cycle cost, schedule, benefits, and performance targets—

known as acquisition program baselines,24 which are used to monitor the 

status of the system acquisition throughout the remaining phases of its life 

cycle. 

Through its NAS modernization program, FAA is upgrading and replacing 

ATC facilities and equipment to help improve the system’s safety, efficiency, 

and capacity. These systems involve improvement in the areas of 

automation, communication, navigation and landing, surveillance, and 

weather to support the following five phases of flight (see fig. 1):

• Preflight – The pilot performs flight checks and the aircraft is pushedback from the gate. For preflight, we looked at Collaborative Decision 

Making (CDM) and OASIS.

• Airport Surface – The aircraft taxis to the runway for takeoff or, after 

landing, to the destination gate to park at the terminal. For airport 

surface, we examined the Airport Surface Detection Equipment – Model 

X (ASDE-X).

• Terminal Departure – The aircraft lifts off the ground and climbs to a 

cruising altitude. For terminal departure, we examined the following 

systems: Airport Surveillance Radar (ASR-11), Integrated Terminal 

Weather System (ITWS), Local Area Augmentation System (LAAS), 

Standard Terminal Automation Replacement System (STARS), and 

Traffic Management Advisor (TMA).

• En route/Oceanic -- The aircraft travels through one or more center 

airspaces and approaches the destination airport. For en route and 

oceanic, we examined the following systems: Air Traffic Control Radar 

Beacon Interrogator-Replacement (ATCBI-6), Advanced Technologies 

and Oceanic Procedures (ATOP), Controller-Pilot Data Link 

Communications (CPDLC), and User Request Evaluation Tool (URET). 

24In December 2004, FAA revised its Acquisition Management System, including changing 

the name Acquisition Program Baseline to Exhibit 300 Program Baseline. 
Page 10 GAO-05-331 National Airspace System

• Terminal Arrival -- The pilot lowers, maneuvers, aligns, and lands the 

aircraft on the destination airport’s designated landing runway. For 

terminal arrival, we looked at the systems already listed under terminal 

departure: ASR-11, ITWS, LAAS, STARS, and TMA. 

In addition, for the major ATC systems that support multiple phases of 

flight, we examined the following systems: En Route Communications 

Gateway (ECG), En Route Automation Modernization (ERAM), NextGeneration Air-to-Ground Communication (NEXCOM), and Wide Area 

Augmentation System (WAAS). Furthermore, for major ATC systems that 

support NAS infrastructure, we examined FAA Telecommunications 

Infrastructure (FTI) and NAS Infrastructure Management System (NIMS)– 

Phase Two.25 (See app. I for additional information on these 16 systems.)

Figure 1: Sixteen Major Systems We Examined in Detail by Phase of Flight

a

CDM, TMA, and URET are decision support tools that fall under the Free Flight program, which is 

currently called Free Flight Phase 2 (FFP2). We reviewed FFP2 as a single system acquisition. 

25Air Traffic Control involves a number of other systems, such as the Common Automated 

Radar Terminal System, used in the terminal arrival and terminal departure phases.

Preflight

Multiple stages of flight

ECG, ERAM, NEXCOM, WAAS

Infrastructure

FTI, NIMS

Airport

surface

Terminal

departure

En route/

oceanic

Terminal

arrival

Airport

surface

CDMa

OASIS

ASDE-X ASR-11

ITWS

LAAS

STARS

TMAa

ATCBI-6

ATOP

CPDLC

URETa

ASR-11

ITWS

LAAS

STARS

TMAa

ASDE-X

Source: FAA.
Page 11 GAO-05-331 National Airspace System

FAA Has Had Difficulty 

Meeting Cost, 

Schedule, and/or 

Performance Targets 

for Major System 

Acquisitions, but Made 

Progress in Fiscal Year 

2004

For more than two decades, FAA has experienced cost growth, schedule 

extensions, and/or performance problems in acquiring major systems 

under its ATC modernization program and has been on our list of high-risk 

programs since 1995. For example, 13 of the 16 major system acquisitions 

we reviewed in detail continue to experience cost, schedule, and/or 

performance shortfalls when assessed against their original baselines. The 

three other major system acquisitions that we reviewed in detail are 

currently operating within their original cost, schedule, and performance 

targets, but are experiencing challenges symptomatic of past problems. Of 

the remaining 39 system acquisitions within the ATC modernization 

program, few have had problems meeting cost and schedule targets.26

However, the ATO made progress during its first year of operation by 

meeting its acquisition goal for fiscal year 2004.

Thirteen of the 16 Major 

ATC System Acquisitions 

We Reviewed in Detail 

Continue to Experience 

Shortfalls When Assessed 

against Original 

Performance Targets

Thirteen of the 16 major system acquisitions that we reviewed in detail for 

this engagement under the ATC modernization program have continued to 

experience cost growth, schedule delays, and/or performance problems 

when assessed against their original performance targets (see table 1). 

These major system acquisitions had total cost growth ranging from $1.1 

million to about $1.5 billion over their original cost targets. In addition, 

these systems required extensions in their initial deployment schedules 

ranging from 1 to 13 years. Furthermore, several systems experienced 

safety-related performance problems. 

26Many of these systems are referred to as “buy-it-by-the-pound” systems, which, generally, 

are commercially available at a set level of performance, and, therefore, do not have 

performance goals per se. 
Page 12 GAO-05-331 National Airspace System

Table 1: Changes in Cost and Schedule Targets for 16 Major ATC System Acquisitions

Dollars in millions

Cost targets Last-site implementation targets

ATC system

Original 

date

Original

cost

Current cost

(as of March

2005) Change

Original

date

Current

date

Change (in

years)

Airport Surface Detection 

Equipment – Model X 

(ASDE-X)

September 

2001

$424.3 $510.2 $85.9a 2007 2009b 2

Airport Surveillance 

Radar Model – 11 (ASR11)

November 

1997

$743 $916 $173 2005 2013 8

ATC Radar Beacon 

Interrogator – 

Replacement (ATCBI-6)

August 

1997

$281.8 $282.9 $1.10 2004 2008 4

Advanced Technologies 

and Oceanic Procedures 

(ATOP) 

June 2001 $548.2 $548.2 None 2006 2006 None

Controller-Pilot Data Link 

Communications 

(CPDLC) 

1999 $166.7 To be

determined

N/A June 2005 To be

determined

N/A

En Route 

Communications 

Gateway (ECG) 

March 

2002

$245.2 $245.2 None 2005 2005 None

En Route Automation 

Modernization (ERAM) 

June 2003 $2,150 $2,150 None December

2010

December

2010

None

Free Flight Phase 2 

(FFP2) 

June 2002 $546.2 $546.2 None 2006 2007 1

FAA Telecommunications 

Infrastructure (FTI) 

July 1999 $205.7 $310.2 $104.5c 2008 2008 None

Integrated Terminal 

Weather System (ITWS) 

June 1997 $276.1 $286.1 $10.0 July 2003 2009+ 6+

Local Area Augmentation 

System (LAAS) 

January 

1998

$530.1 $696.1 $166.0 2006 To be

determined

N/A

Next Generation Air-toGround Communication 

(NEXCOM) 

September 

1998

$405.7

(First segment

only)

$986.4

(First segment

only)

$580.7 2008 To be

determined

N/A

NAS Infrastructure 

Management System – 

Phase 2 (NIMS–2)

May 2000 $172.9 $172.9 None 2005 2010d 5

Operational and 

Supportability 

Implementation System 

(OASIS) 

April 1997 $174.7 $155.50 ($19.2) 2001 2004 3
Page 13 GAO-05-331 National Airspace System

Source: GAO presentation of FAA data.

N/A: Not applicable.

a

According to FAA officials, the change in cost target for ASDE-X was due to an increase in the scope 

of the project.

b

FAA plans to extend ASDE-X’s current deployment target from 2007 to 2009 because the project’s 

budgets were cut in fiscal years 2004 and 2005.

c

The increased costs were for requirements which, while included in the original baseline, were 

unknown at the time the original baseline was prepared.

d

In light of reduced funding, FAA is revising NIMS-2’s targets; a Joint Resource Council decision is 

planned for May 2005.

e

September 1999 and May 2004 estimates for WAAS development exclude $1.3 billion in satellite 

communications leases.

For 12 of the 13 major system acquisitions27 we reviewed in detail with 

cost, schedule, and performance shortfalls, one or more of the following 

four key factors contributed to these shortfalls:

(1) The funding level received was less than called for in agency 

planning documents. Most major ATC system acquisitions have cost, 

schedule, and performance baselines that are approved by FAA’s Joint 

Resources Council--the agency’s body responsible for approving and 

overseeing major system acquisitions. Each baseline28 includes annual 

funding levels that the council agrees are needed for a system acquisition to 

meet its cost, schedule, and/or performance targets. The estimated cost for 

a given year assumes that the program received all funding for prior fiscal 

Standard Terminal 

Automation Replacement 

System (STARS) 

February 

1996

$940 $1,460

(Phase 1 only)

$520 2005 2008 3

Wide Area Augmentation 

System (WAAS) 

1994 $509 $2,036e $1,527 December

2000

2013 13

(Continued From Previous Page)

Dollars in millions

Cost targets Last-site implementation targets

ATC system

Original 

date

Original

cost

Current cost

(as of March

2005) Change

Original

date

Current

date

Change (in

years)

27FAA Telecommunications Infrastructure was not directly affected by these four factors, 

but did experience cost growth.

28In December 2004, FAA revised its acquisition management system policy by replacing the 

requirement for an acquisition program baseline with a requirement for preparing an OMB 

Exhibit 300 Baseline, which includes additional information required for FAA’s annual 

budget formulation and submission process. 
Page 14 GAO-05-331 National Airspace System

years as described in the baseline. In practice, however, this is not always 

the case. For example, when FAA’s budget level does not allow all system 

acquisitions to be fully funded at the levels approved in their baselines, 

FAA may elect to fully fund higher-priority acquisitions and provide less 

funding for lower-priority acquisitions than called for in their baselines. 

When a system acquisition does not receive the annual funding levels called 

for in its baseline, its ability to meet cost, schedule, and/or performance 

targets can be jeopardized, for example, by requiring the agency to defer 

funding for essential development or deployment activities until sufficient 

funding becomes available, which, in turn, could require FAA to maintain 

costly legacy systems until a new system is deployed. Receiving less 

funding than the agency approved for a given acquisition was a factor 

contributing to the inability of 8 of the 16 major system acquisitions we 

reviewed in detail to meet their cost, schedule, and/or performance targets. 

The ASR-11 acquisition, a digital radar system, illustrates how reduced 

funding has resulted in schedule delays. FAA officials stated that because 

of funding reductions and reprogramming, the program received $46.45 

million less than requested for fiscal years 2004 and 2005 and program 

officials plan to request that the program’s deployment schedule be 

extended to 2013.29 According to FAA officials, in general, schedules for 

system acquisitions may slip under such circumstances (e.g., the rate of 

software development may be reduced and planned hardware and software 

deployments may be delayed). The ATO’s chief operating officer testified in 

April 2005 that receiving multiyear rather than annual funding from 

Congress for system acquisitions would help FAA to address this problem 

by providing funding stability for system acquisitions. In addition, 

according to a senior DOT official, 50 percent of cost growth is a result of 

an unstable funding stream. 

(2) The system acquisition experienced requirements growth and/or 

unplanned work. Requirements that are inadequate or poorly defined prior 

to developing a system may contribute to the inability of system 

acquisitions to meet their original cost, schedule, and/or performance 

targets. In addition, unplanned development work can occur when the 

agency misjudges the extent to which commercial-off-the-shelf (COTS)/ 

29The ASR-11 program is scheduled to go to the Joint Resources Council in fiscal year 2005 

to extend the program’s schedule to 2013 and to revise the baseline funding. 
Page 15 GAO-05-331 National Airspace System

nondevelopmental item (NDI)30 solutions, such as those procured by 

another agency, will meet FAA’s needs. Requirements growth and/or 

unplanned work contributed to the inability of 7 of the 16 major system 

acquisitions we reviewed in detail to meet their cost, schedule, and/or 

performance targets. 

(3) Stakeholders were not sufficiently involved in design and 

development: Insufficient involvement of relevant stakeholders, such as air 

traffic controllers and maintenance technicians, throughout the 

development and approval processes for a system acquisition can lead to 

costly changes in requirements and unplanned work late in the 

development process. Not involving stakeholders sufficiently contributed 

to the inability of 4 of the 16 major system acquisitions to meet their cost, 

schedule, and/or performance targets. 

(4) The complexity of software development was underestimated.31

Underestimating the complexity of developing software for system 

acquisitions or the difficulty of modifying available software to fulfill FAA’s 

mission needs may contribute to unexpected software development, higher 

costs, and schedule delays. Underestimation contributed to the inability of 

3 of the 16 major system acquisitions we reviewed in detail to meet their 

cost, schedule, and/or performance targets. (See table 2.)

30FAA defines a COTS item as a product or service that has been developed for sale, lease, or 

license to the general public. The product is currently available at a fair market value. FAA 

defines a NDI as an item that was previously developed for use by a government (federal, 

state, local, or foreign) and that requires limited further development. For example, the 

Army’s SINCGARS radio is the core of FAA’s NEXCOM radio, and the software FAA selected 

for ATOP was NDI software from New Zealand’s air navigation system.

31For purposes of this report, the underestimation of software complexity refers to poor 

estimation of the level of effort that would be required to modify software to meet 

requirements (e.g., COTS or NDI).
Page 16 GAO-05-331 National Airspace System

Table 2: Four Key Factors Contributing to Cost Growth, Schedule Extensions, and/or Performance Problems for 13 ATC System 

Acquisitions

Source: GAO presentation of FAA data.

Note: Blank spaces in the chart denote that the specific factor was not a key contributor to a program’s 

inability to meet cost, schedule, or performance targets.

a

FTI was not directly impacted by any of these four factors, but did experience cost growth.

Several of the 16 major systems acquisitions we reviewed in detail 

effectively illustrate how these four factors can interact to contribute to 

cost growth, schedule extensions, and performance problems. For 

example, for WAAS, a precision approach and landing system augmented 

by satellites, two of the four key factors came into play: underestimation of 

software complexity and insufficient stakeholder involvement. Specifically, 

FAA underestimated the complexity of the software that would be needed 

to support this system when it accelerated the implementation of 

performance targets, which included moving up the commissioning of 

WAAS by 3 years. FAA originally planned to commission WAAS by 2000; 

however, at the urging of government and aviation industry groups in the 

1990s, it decided to change the commissioning date to 1997. FAA then tried 

to develop, test, and deploy WAAS within 28 months, although the software 

development alone was expected to take 24 to 28 months. 

Name of system 

The funding level 

received was less 

than called for in 

agency planning 

documents 

The system acquisition 

experienced requirements 

growth and/or unplanned 

work

The complexity of 

software development 

was underestimated 

Stakeholders were 

not sufficiently 

involved 

ASDE-X X

ASR-11 X X

ATCBI-6 X

CPDLC X

FFP2 X

ITWS X X X

LAAS X X X

NEXCOM X X

NIMS-2 X X

OASIS X X X

STARS X X

WAAS X X

FTIa
Page 17 GAO-05-331 National Airspace System

In retrospect, FAA acknowledged that the agency’s in-house technical 

expertise was not sufficient to address WAAS’s technical challenges and 

that expert stakeholders should have been involved earlier. Although 

WAAS was being developed by an integrated product team that included 

representatives from several FAA offices, the team did not effectively 

resolve problems in meeting a required performance capability—that pilots 

be warned in a timely manner when a system may be giving them 

potentially misleading and therefore hazardous information. Consequently, 

in 2000, FAA convened a panel of expert stakeholders to help it meet this 

requirement. These actions resulted in unplanned work and contributed to 

the rise in WAAS’s cost from the original estimate of $509 million in 1994 to 

$2.036 billion in 2005, and to a 6-year extension in its commissioning date. 

According to FAA, adding 6 years to the program’s life cycle also 

contributed to increased costs.32

Another example involves STARS, a joint program of FAA and DOD that 

replaced outdated monochromatic controller workstation monitors with 

multicolor monitors in ATC facilities. While joint FAA and DOD 

acquisitions offer the opportunity to leverage federal resources, in the case 

of STARS, the interaction of insufficient stakeholder involvement and 

subsequent unplanned work contributed to cost growth and schedule 

extensions. Specifically, FAA and DOD decided to acquire COTS 

equipment, rather than developing a new system. This strategy envisioned 

immediately deploying STARS to the highest priority ATC facilities and 

making further improvements later, thereby avoiding the increasing cost of 

maintaining the legacy system. However, this strategy provided for only 

limited evaluation by FAA and DOD controllers and maintenance 

technicians during the system’s development phase, although these 

employees were identified as stakeholders in developing the system’s 

requirements. While DOD controllers adopted and began using the original 

COTS version of STARS, FAA elected to modify the acquisition strategy and 

suspended the STARS deployment to address FAA controller and 

technician concerns with the new system. These concerns included, for 

example, that many features of the old equipment could be operated with 

knobs, allowing controllers to focus on the screen. By contrast, STARS was 

menu-driven and required the controllers to make several keystrokes and 

use a trackball, diverting their attention from the screen. The maintenance 

32FAA also transferred $1.3 billion--the cost of satellite leases--from the operations account 

to the facilities and equipment account, bringing the total estimate at completion cost to 

$3.3 billion.
Page 18 GAO-05-331 National Airspace System

technicians also identified differences between STARS and its backup 

system that made it difficult to monitor the system. For example, the visual 

warning alarms and the color codes identifying problems were not the 

same for the two systems.

According to FAA, the original COTS acquisition strategy that limited the 

involvement of controllers and maintenance technicians to just prior to 

deployment caused unplanned work for the agency because it had to revise 

its strategy for acquiring and approving STARS; this contributed to an 

increase in the overall cost of STARS of $500 million and a schedule 

extension of 5 years to deploy the system to its first site. The interaction of 

these factors also contributed to the agency’s ability to deploy STARS at 

only 47 of the 172 facilities initially planned. As of February 2005, FAA was 

developing a long-term acquisition plan to modernize or upgrade the 

highest-priority Terminal Radar Approach Control facilities that direct 

aircraft in the airspace that extends from the point where the tower’s 

control ends to about 50 nautical miles from the airport. The plan consists 

of alternatives to STARS, including the existing Common Automated Radar 

Terminal System (CARTS), which STARS was designed to replace.33 Finally, 

to help avoid similar problems in the future, stemming from the insufficient 

involvement of stakeholders during critical phases of a system’s design, 

development, and implementation, FAA has been more proactive in 

involving the stakeholders that will operate and maintain system 

acquisitions. 

A final example of how these factors can interact is FAA’s acquisition of 

OASIS, which is designed to replace outdated technology in FAA’s 

automated flight service stations. The new system is intended to improve 

the ability of air traffic specialists34 to process flight plans, deliver weather 

information, and provide search and rescue services to general aviation 

pilots. In August 1997, FAA awarded a contract to replace the Flight Service 

33FAA began fielding CARTS in 1997, as the interim primary terminal automation system 

until it was replaced with STARS. To date, the agency has not ruled out keeping CARTS as 

an alternative, if STARS proves to be unaffordable or does not perform as expected. CARTS 

was not one of the systems FAA was acquiring in fiscal year 2004, when we designed our 

methodology. 

34Air traffic specialists are controllers and automation specialists who work at flight service 

stations throughout the United States and provide, among other things, briefings of weather 

conditions along a pilot’s route of flight and information on traffic conditions for landing and 

departing at airports where there is no control tower and no restrictions on the use of 

airspace.
Page 19 GAO-05-331 National Airspace System

Automation System and console workstations. However, unplanned work, 

insufficient involvement of stakeholders, and lower funding than the 

agency had determined was needed to meet cost, schedule, and 

performance targets have together contributed to cost growth and 

schedules extensions. For example, the agency saw the system acquisition 

schedule slip because of a larger-than-planned development effort. 

According to the DOT IG, FAA identified a number of significant concerns, 

including the inadequate weather graphics capabilities for air traffic 

specialists. In our view, this indicates that stakeholders were not 

sufficiently involved throughout the system’s design and development 

phases. As a result, FAA eliminated the option of COTS procurement. In 

addition, the OASIS program was rebaselined in March 2000, when the 

system acquisition received only $10 million of the $21.5 million called for 

in its baseline for that year. This reduction in funding reduced the rate of 

software development, delayed and reduced the rate of planned hardware 

and console deployments, and led to the incremental deployment of 

operational software. This contributed to a delay in the first-site 

implementation from July 1998 to July 2002. According to FAA officials, 

because OASIS received less funding than the agency had approved for 

fiscal year 2004 and 2005, its deployment to automated flight service 

stations was postponed. 

As of February 2005, FAA had deployed 19 OASIS units: 16 at automated 

flight service stations and 3 at other sites. Software upgrades that are under 

way will be completed by June 2005. FAA plans neither installations nor 

software upgrades beyond those at the automated sites, because the 

agency awarded a contract to a private vendor in February 2005 to operate 

flight service stations. Until then, FAA has directed the program to remain 

within its current Capital Investment Plan funding levels for fiscal years 

2004 through 2006.35 According to FAA, since it completed its evaluation of 

OASIS in February 2005, planning for the program’s implementation and 

baseline remain unchanged. FAA plans to phase out OASIS between March 

2006 and March 2007 in accordance with the new service provider’s 

transition plan. 

35The Capital Investment Plan, a 5-year financial plan, allocates funds to NAS projects on the 

basis of a detailed analysis of project funding by FAA functional working groups. The plan 

includes estimates for the current fiscal-year budget and for 4 future-year expenditures for 

each line item in the facilities and equipment budget.
Page 20 GAO-05-331 National Airspace System

Three of the Major ATC 

System Acquisitions We 

Reviewed in Detail 

Currently Operate within 

Their Original Cost, 

Schedule, and Performance 

Targets, Despite Challenges

Three of the 16 major ATC system acquisitions we reviewed in detail are 

currently operating within their original cost, schedule, and performance 

targets; however they have experienced challenges, including symptoms of 

one or more of the four factors cited earlier, such as requirements growth. 

These system acquisitions include (1) ECG, a communications system 

gateway that serves as the point of entry and exit for data used by FAA 

personnel to provide air traffic control at 20 en route facilities; (2) ERAM, a 

replacement for the primary computer system used to control air traffic; 

and (3) ATOP, an integrated system for processing flight data for oceanic 

flights. 

While ECG has not exceeded its original cost, schedule, and performance 

targets, it encountered requirements growth when FAA added a new 

capability to address a security weakness. According to FAA officials, 

correcting this weakness cost about $25,000, and an additional $480,000 

will likely be needed to improve the monitoring capability for this system’s 

operation. However, these cost increases will not exceed the system’s cost 

or schedule targets. ERAM and ATOP also have areas that warrant 

attention. For example, ERAM is a high-risk effort because of its size and 

the amount of software that needs to be developed—over 1 million lines of 

code are expected to be written for this effort. In addition, the DOT IG 

reports that, to date, ERAM has experienced software growth of about 

70,000 lines of code. While the DOT IG considers this amount of software 

growth to be modest, given FAA’s long-standing difficulties with developing 

this volume of software for system acquisitions while remaining within 

cost, schedule, and/or performance targets, sustained management 

attention is warranted. For ATOP, when FAA tried to accelerate the initial 

deployment of this system by 14 months, it was unable to do so, because of 

poorly defined requirements, unrealistic schedule estimates, and 

inadequate evaluation by the contractor. In addition, according to contract 

provisions, FAA assumed responsibility in February 2005 for the cost of 

resolving any additional software problems it identifies. 

Overall, although these system acquisitions are currently operating within 

their cost, schedule, and performance targets, the challenges they have 

experienced thus far indicate that they will require the sustained attention 

of FAA’s senior managers to help ensure that they stay on track.36

36GAO-05-207.
Page 21 GAO-05-331 National Airspace System

FAA Has Experienced Cost 

Growth and Schedule 

Extensions for the 

Remaining 39 System 

Acquisitions under the ATC 

Modernization Program

For the 39 system acquisitions that make up the balance of FAA’s ATC 

modernization program, only 9 are considered “major” or directly 

comparable to the 16 major ATC system acquisitions we reviewed in 

detail.37 (See table 3.) Of these 9 major systems, 2 have required changes in 

their cost targets. For example, for an automated weather observation 

system, the Aviation Surface Weather Observation Network,38 the cost has 

increased by 15 percent because of system capacity issues, among other 

things. For another system that will be used on an interim basis for 

managing air traffic until the new primary computer system is available, the 

Host and Oceanic Computer System Replacement, the cost has decreased 

by 13 percent because the agency determined that parts of the existing 

system could be sustained through fiscal year 2008, which is within the 

scope of the program.39 The remaining 30 systems are not directly 

comparable, because they do not involve acquiring a new system. Instead, 

they are what FAA terms “buy-it-by-the pound” purchases—systems that 

are commercially available and ready for FAA to use without modification, 

such as a landing system purchased to replace one that has reached the end 

of its useful life. (See app. II for additional information on these 39 

systems.)

37As mentioned previously, FAA does not have a formal definition of “major” systems, but 

suggested that we consider a system as major if it has a baseline for cost, schedule, and 

performance formally approved by senior agency officials. Using this definition, we 

consider 9 of the remaining 39 systems major. These 9 major systems bring the total number 

of major systems under the ATC modernization program to 25.

38Aviation Surface Weather Observation Network (ASWON) automates surface weather 

observation information, replacing labor-intensive and high-cost manual surface weather 

observations.

39The Host and Oceanic Computer System Replacement (HOCSR) is an interim upgrade and 

modernization program designed to replace the En Route Host Computer hardware, 

software, and peripheral equipment to reduce delays and improve reliability. 
Page 22 GAO-05-331 National Airspace System

Table 3: Description and Status of Nine Additional Major ATC System Acquisitions with Cost, Schedule, and Performance 

Targets 

Dollars in millions

ATC system acquisition and system description

Development costs Deployment schedule

Original Current Original Current

HOST/Oceanic Computer System Replacement (HOCSR) -

The HOCSR program replaces the main ATC computer processor and 

some peripherals, while ensuring the supportability of other peripherals 

until they are replaced by En Route Automation Modernization 

(ERAM). 

$424.10 $368.50 Start: December 

1998

Finish:June 

2004

Start: December 

1998

Finish: April 2004

Command Center Conference Control System (CCS) - Replace 

OTS - This ongoing program involves replacing the existing telephone 

system at the FAA Air Traffic Control System Command Center 

(ARCSCC) in Herndon, Va. The existing telephone system is becoming 

unsupportable and can no longer perform ARCSCC command 

functions.

12.70 12.70 Start: Fiscal 

Year 2005 

Finish: Fiscal 

Year 2005

Start: Fiscal Year

2005

Finish: Fiscal Year 

2005

Ultra High Frequency (UHF) Radio Replacement - The UHF radio 

replacement project replaces aging equipment used to communicate 

with DOD aircraft. FAA maintains the UHF air and/or ground 

communication service for air traffic control of military operations in the 

United States. 

85.15 85.15 Start: Fiscal 

Year 2003

Finish:

Fiscal Year 2010

Start: Fiscal Year 

2010

Finish:

Fiscal Year 2010

Capstone Phase 1 - Capstone is a congressionally directed 

demonstration program primarily intended to improve aviation system 

safety in Alaska through the introduction of new communications, 

navigation, and surveillance technologies. The Capstone program is a 

part of a larger program known as the Safe Flight 21 Program (SF-21), 

which is designed to establish pockets of broadcast service technology 

enhancements to support the demonstration of new technology-driven 

safety and efficiency benefits. 

18.55 18.55 Start: Fiscal 

Year 2000

Finish:

Fiscal Year 2003

Start: N/A

Finish:

N/A

ASR-9 / Mode S Service Life Extension Program (SLEP) - The 

ASR-9 program provides aircraft detection and separation services at 

congested airports, which reduces aircraft delays and improves safety. 

186.50 186.50 Start: TBD

Finish:

TBD

Start: TBD

Finish:

TBD

Precision Runway Monitor (PRM) – The PRM system is an accurate, 

electronic scan radar that tracks and processes aircraft targets at a 1- 

second update rate. 

145.80 145.80 Start: October 

1997

Finish:

2007

Start: October 

1997

Finish: January 

2007

En Route System Modification – This program will replace obsolete 

en route components, such as processors; upgrade the controllers’ 

displays and the infrastructure that supports those displays; and 

configure the consoles to accommodate additional processors. 

201.90 201.90 Start: N/A

Finish: May 

2009

Start: N/A

Finish: N/A

Initial Academy Training System (IATS) – This high-fidelity training 

system for the FAA Academy will enable the training of an increasing 

number of new air traffic controllers as the existing workforce retires.

23.35 23.35 Start: 

September 2005

Finish: 

September 2005

Start: September 

2005

Finish: September 

2005
Page 23 GAO-05-331 National Airspace System

Source: GAO presentation of FAA data.

To its credit, FAA has reported that it met its annual acquisition 

performance goal for fiscal year 2004--to meet 80 percent of designated 

milestones and maintain 80 percent of critical program costs within 10 

percent of the budget as published in its Capital Investment Plan.40

Specifically, it set annual performance cost goals and schedule milestones 

for 41 of the 55 system acquisitions under the ATC modernization program. 

For these 41 system acquisitions, FAA set 51 schedule milestones and met 

46 of them—with “meeting the goal” defined as achieving 80 percent of its 

designated program milestones. It also set and met its annual cost 

performance goals for each of these 41 system acquisitions. In our opinion, 

having and meeting such performance goals is commendable, but it is 

important to note that these goals are updated program milestones and 

cost targets, not those set at the program’s inception.41 Consequently, they 

do not provide a consistent benchmark for assessing progress over time. 

Moreover, as indicators of annual progress, they cannot be used in isolation 

to measure progress in meeting cost and schedule targets over the life of an 

acquisition. Finally, given the problems FAA has had in acquiring major 

ATC systems for over two decades, it is too soon to tell whether meeting 

these annual performance goals will ultimately improve the agency’s ability 

to deliver system acquisitions as promised.

Aviation Surface Weather Observation Network (ASWON) – The 

primary purpose of ASWON is to support FAA and National Weather 

Service (NWS) modernization by automating surface weather 

observation to meet the needs of pilots, operators, and air traffic 

personnel without incurring the high costs of labor-intensive manual 

surface weather observations. 

$350.90 $403.80 Start: 

September 2002

Finish:

September 2010

Start: Unknown

Finish:

Unknown

(Continued From Previous Page)

Dollars in millions

ATC system acquisition and system description

Development costs Deployment schedule

Original Current Original Current

40According to FAA, 43 capital projects were included in the fiscal year 2004 acquisition 

performance goal--41 of these projects fall under the ATC modernization program. 

41Our statements about meeting cost, schedule, and/or performance targaets in this report 

and in our past reports are based on the original targets that FAA established and approved 

at the start of its acquisition programs.
Page 24 GAO-05-331 National Airspace System

FAA Has Taken Some 

Positive Steps to 

Address Key Legacy 

Challenges, but 

Additional Steps Are 

Warranted to Reduce 

Risk and Strengthen 

Oversight 

FAA has taken a number of positive steps, primarily through the ATO, to 

address key legacy challenges in acquiring major systems under its ATC 

modernization program; however, we have identified additional steps that 

are warranted to reduce risk and strengthen oversight. Some of the steps 

FAA has taken directly address the four factors we identified as 

contributing to cost, schedule, and/or performance problems, while others 

support more general efforts to improve the modernization program’s 

management. The steps taken and additional steps needed are discussed 

below by key areas. 

Steps Taken to Address the 

Four Factors We Identified 

As Contributing to 

Performance Shortfalls and 

Additional Steps Needed

To address the concern that some system acquisitions have had difficulty 

meeting performance targets because they have not received annual 

funding at the levels called for in key planning documents, the ATO has 

taken several steps. For example, the ATO has demonstrated a willingness 

to cut major programs that were not meeting their performance targets 

even after a significant investment of agency resources. The ATO is 

currently reviewing all of its capital projects to reassess priorities. Both of 

these actions should help improve the chances that sufficient funding will 

be available for priority system acquisitions to conduct the annual activities 

necessary to keep them on track to meet cost, schedule, and performance 

targets. 

Specifically, for fiscal year 2005, the appropriation for FAA’s facilities and 

equipment budget, which funds the ATC modernization program, was $393 

million less than the agency had planned to spend. FAA absorbed the $393 

million reduction largely by cutting funding for three of the major system 

acquisitions we reviewed in detail: a digital e-mail-type capability between 

controllers and pilots was suspended (CPDLC);the next generation air-toground communication system had the funding cut for a major component 

(NEXCOM); and a precision-landing system augmented by satellites for use 

primarily by commercial airlines (LAAS) was returned to research and 

development to focus the remaining funding for the system on resolving a 

key performance shortfall. FAA also plans to defer funding for CPDLC and 

LAAS for fiscal year 2006. 

FAA decisions to cut or eliminate funding for system acquisitions in its 

current ATC modernization system may prove to be positive in the long 

run. For example, although FAA and National Air Traffic Controllers 
Page 25 GAO-05-331 National Airspace System

Association officials say that the cuts the agency made to 3 of its 16 major 

ATC system acquisitions will delay system benefits until the acquisitions 

are fully developed and deployed, the cuts demonstrate FAA’s willingness 

to suspend major ATC system acquisitions, despite large resource 

investments. In addition, by delaying a system acquisition, FAA may later 

be able to save time and money by leveraging the experiences that others 

have had with developing and deploying systems that provide similar 

capabilities (e.g., the controller-pilot e-mail-type capability for which FAA 

cut funding is now in use in both Canada and Europe). Furthermore, as 

FAA continues to reassesses its funding priorities, it could explore costsaving options including taking steps to systematically (1) evaluate the 

costs and benefits of continuing to fund system acquisitions across the ATC 

modernization program at current and planned levels to identify potential 

areas for savings and (2) identify potentially lower-cost alternatives to 

current system acquisitions, such as lower-cost controller workstations. 

FAA has also taken a number of steps to address two other factors—reduce 

the risk of requirements growth and/or the need to undertake unplanned 

work—and to improve its ability to better assess and manage the risks 

associated with acquiring major ATC systems that require complex 

software development. However, additional steps are needed in these 

areas. 

• Processes for acquiring software and systems: FAA has made progress 

in improving its process for acquiring software-intensive systems--

including establishing a framework for improving its system 

management processes, and performing many of the desired practices 

for selected FAA projects.42 The quality of these systems and software, 

which are essential to FAA’s ATC modernization program, depends on 

the value and maturity of the processes used to acquire, develop, 

manage, and maintain them. In response to our previous 

recommendations, FAA developed an FAA-integrated capability 

maturity model (iCMM). Since FAA implemented the model, a growing 

number of system acquisitions have adopted the model, and its use has 

paid off in enhanced productivity, higher quality, greater ability to 

predict schedules and resources, better morale, and improved 

communication and teamwork. However, ATO did not mandate the use 

of the process improvement model for all software-intensive acquisition 

42GAO, Air Traffic Control: System Management Capabilities Improved, but More Can Be 

Done to Institutionalize Improvements, GAO-04-901 (Washington, D.C.: Aug. 20, 2004).
Page 26 GAO-05-331 National Airspace System

projects. In response to our recommendation, the ATO informed us of 

its plans to establish, by June 30, 2005, an overall policy defining the 

ATO’s expectations for process improvement, and by September 30, 

2005, a process improvement plan to address and coordinate 

improvement activities throughout the organization.

• Management of information technology investments: In 2004, we 

reported that FAA has made considerable progress in managing its 

information technology investments.43 However, we also found that 

FAA’s lack of regular review of investments that are more than 2 years 

into their operations is a weakness in the agency’s ability to oversee 

more than $1 billion of its information technology investments as a total 

package of competing investment options and pursue those that best 

meet the agency’s goals. FAA recently informed us that it has taken a 

number of steps aimed at achieving a higher maturity level, including 

establishing service-level mission need statements and service-level 

reviews, which address operational systems to ensure that they are 

achieving the expected level of performance. While these steps could 

resolve some of the deficiencies that we previously reported, we have 

not yet performed our own evaluation of these steps. FAA could 

potentially realize considerable savings or performance improvements if 

these reviews result in the discontinuation of some investments, since 

operating systems beyond their second year of service accounted for 37 

percent of FAA’s total investment in information technology in fiscal 

year 2004.

• Enterprise architecture: FAA has established a project office to develop 

a NAS enterprise architecture—a blueprint for modernization—and 

designated a chief architect, and has committed resources to this effort, 

and issued its latest version of its architecture.44 However, FAA has not 

yet taken key steps to improve its architecture development, such as 

designating a committee or group representing the enterprise to direct, 

oversee, or approve the architecture; establishing a policy for 

developing, maintaining, and implementing the architecture; or fully 

developing architecture products that meet contemporary guidance and 

43GAO-04-822. 

44GAO, Federal Aviation Administration: Stronger Architecture Program Needed to Guide 

Systems Modernization Efforts, GAO-05-266 (Washington, D.C.: Apr. 29, 2005).
Page 27 GAO-05-331 National Airspace System

describe both the “As Is” and “To Be” environments and developing a 

sequencing plan for transitioning between the two. 

To help address concerns that stakeholders have not been sufficiently 

involved throughout the development of major systems acquisitions, FAA 

has taken a number of steps. For example, when the ATO was created, it 

brought together the FAA entities that develop systems and those who will 

ultimately use them. Specifically, it reorganized FAA’s air traffic services 

and research and acquisition organizations along functional lines of 

business to bring stakeholders together and integrate goals. The ATO is 

also continuing with a phased approach to system acquisitions that it began 

using under Free Flight Phase 1,45 through which it has begun to involve 

stakeholders more actively throughout a system acquisition’s development 

and deployment. However, as we reported in November 2004, FAA needs to 

take additional steps to ensure the continued and active involvement of 

stakeholders in certifying new ATC system acquisitions.46 In addition, the 

union that represents the specialists who install, maintain, troubleshoot, 

and certify NAS systems, recently testified that over the past 2 years, FAA 

has systematically eliminated the participation of these specialists in all but 

a few modernization programs.47 Given the importance of stakeholder 

involvement in the development and deployment of new ATC systems, their 

continued involvement in ATC modernization efforts will be important to 

help avoid the types of problems that led to cost growth and delays for 

STARS. 

Other Steps FAA Has Taken 

to Improve the 

Modernization Program’s 

Management and Additional 

Steps That Are Needed 

Reassessment of capital investment to decrease operating costs: Both the 

FAA Administrator and the ATO’s chief operating officer have committed to 

basing future funding decisions for system acquisitions on their 

contribution to reducing the agency’s operating costs while maintaining 

safety. This is consistent with our 2004 recommendation that FAA consider 

its total portfolio of investments as a package of competing options. 

45Under Free Flight Phase 1, FAA developed a suite of tools to assist controllers with 

managing air traffic.

46GAO-05-11.

47On Transforming the Federal Aviation Administration: A Review of the Air Traffic 

Organization (ATO) and the Joint Program Development Office (JPDO), Statement of 

Thomas Brantley, President, Professional Airways Systems Specialists (PASS) AFL-CIO, 

before the House Committee on Transportation and Infrastructure, Subcommittee on 

Aviation, April 7, 2005.
Page 28 GAO-05-331 National Airspace System

Currently, only 1 of the 55 system acquisitions in FAA’s ATC modernization 

program—FAA Telecommunications Infrastructure—helps to reduce the 

agency’s operating costs. Most of FAA’s major system acquisitions are 

aimed at increasing the capacity of the NAS and delivering benefits to 

system users. The ATO is in the process of reviewing all of its capital 

investments, including system acquisitions under the ATC modernization 

program, to identify areas of cost savings and to focus limited funding on 

investments that will reduce operating costs. However, because FAA has 

only recently begun to incorporate this type of analysis of the costs and 

operational efficiency of system acquisitions into the decision-making and 

management processes, it is too early to assess the results. 

Acquisition Management System: The ATO has taken a number of steps to 

improve its Acquisition Management System (AMS). For example, it has 

revised AMS to require that acquisition planning documents be prepared in 

a format consistent with that prescribed by OMB for use in justifying all 

major capital investments. In addition, the ATO revised AMS in December 

2004, in part to respond to recommendations we made about needed 

changes in its investment management practices for information 

technology.48 However, we have not yet independently assessed the 

sufficiency of these changes. Moreover, additional changes to AMS are 

warranted. For example, while AMS provides some discipline for acquiring 

major ATC systems, it does not use a knowledge-based approach to 

acquisitions, characteristic of best commercial and DOD practices. A 

knowledge-based approach includes using established criteria to attain 

specific knowledge at three critical junctures in the acquisition cycle, 

which we call knowledge points, and requiring oversight at the corporate 

executive level for each of these knowledge points. Experience has shown 

that not attaining the level of knowledge called for at each knowledge point 

increases the risk of cost growth and schedule delays.49 We recommended, 

among other things, that FAA take several actions to more closely align its 

acquisition management system with commercial best practices. FAA said 

that our recommendations would be helpful to them as they continue to 

refine this system. 

48GAO-04-822.

49For more information on using a knowledge-based approach, see GAO, Air Traffic 

Control: FAA’s Acquisition Management Has Improved, but Policies and Oversight Need 

Strengthening to Help Ensure Results, GAO-05-23 (Washington, D.C.: Nov. 12, 2004).
Page 29 GAO-05-331 National Airspace System

Cost accounting and cost estimating practices: FAA has improved its 

financial management by moving forward with the development of a cost 

accounting system, which it plans to fully deploy by 2006. Ultimately, FAA 

plans to use this cost information routinely in its decision-making. When 

implemented, this cost accounting system will address a long-standing 

GAO concern that FAA has not had the needed cost accounting practices in 

place to effectively manage software-intensive investments, which 

characterize many of agency’s major ATC system acquisitions. This type of 

information can be used to improve future estimates of cost for these 

acquisitions.50

Organizational culture: FAA has also sought to establish an organizational 

culture that supports sound acquisitions. We have ongoing work to assess 

FAA’s efforts concerning cultural change.

ATO business practices: To improve its investment management decisionmaking and oversight of major ATC acquisitions, the ATO has informed us 

that it has initiated the following steps, which we have reported are 

important to effective oversight:51

• integrated AMS and OMB’s Capital Planning and Investment Control 

Process to develop a process for analyzing, tracking, and evaluating the 

risks and results of all major capital investments made by FAA;

• conducted Executive Council52 reviews of project breaches of 5 percent 

in cost, schedule, and/or performance to better manage cost growth;

• issued monthly variance reports to upper management to keep them 

apprised of cost and schedule trends; and

50GAO, High-Risk Series: An Update, GAO-05-207 (Washington, D.C.: January 2005).

51GAO-05-23; GAO-04-822.

52The ATO’s Executive Council is responsible for further implementing acquisition reform 

for major ATC system acquisitions.
Page 30 GAO-05-331 National Airspace System

• increased the use of cost monitoring or earned value management53

systems to improve oversight of programs.

However, much work remains before the ATO will have key business 

practices in place. 

Specifically, according to the ATO’s chief operating officer, it will be at least 

2 years before the ATO has completed the basic management processes 

needed to use the new financial management systems it has been putting in 

place.

Despite progress to date, until the agency addresses the residual issues 

cited above, it will continue to risk the project management problems 

affecting cost, schedule, and/or performance that have hampered its ability 

to acquire systems for improving air traffic control. 

A Constrained 

Budgetary 

Environment Could 

Further Challenge the 

ATO’s Efforts to 

Modernize the ATC 

System 

The ATO will be further challenged to modernize the ATC system in the 

current constrained budget environment and remain within the 

administration’s future budget targets, which are lower than those of recent 

years. Specifically, for fiscal year 2005, FAA requested $393 million less 

than it had planned to spend for activities under the facilities and 

equipment budget account, which funds the ATC modernization program 

and related modernization activities. In addition, the President’s fiscal year 

2006 budget submission calls for an additional cut to this budget account of 

$77 million from FAA’s planned level, which would bring the fiscal year 

2006 funding level to about $470 million below the fiscal year 2004 

appropriation. Moreover, FAA officials told us that funding for the facilities 

and equipment account is likely to hold near fiscal year 2004 levels, or at 

about $2.5 billion annually, for the next 5 years. In total, FAA plans to spend 

$4.4 billion during fiscal years 2005 through 2009 on key modernization 

efforts, despite FAA receiving about $2 billion less than it had planned in 

appropriations over this 5-year period for its facilities and equipment 

53Earned value management compares the actual work performed at certain stages of a job 

to its actual costs—rather than comparing budgeted and actual costs, the traditional 

management approach to assessing progress. By measuring the value of the work that has 

been completed at certain stages in a job, earned value management can alert program 

managers, contractors, and administrators to potential cost growth and schedule delays 

before they occur and to problems that need correcting before they worsen. 
Page 31 GAO-05-331 National Airspace System

budget, which funds the ATC modernization program and related 

modernization activities.

To fund its major system acquisitions while remaining within the 

administration’s budget targets, the ATO has eliminated planned funding to 

start new projects and substantially reduced planned funding for other 

areas. These funding decisions are reflected in FAA’s updated Capital 

Investment Plan. This plan shows substantially reduced funding for two 

major system acquisitions in fiscal year 2005—CPDLC and LAAS--and 

defers funding for them in fiscal year 2006. For the remaining 14 major ATC 

system acquisitions we reviewed in detail, FAA plans to increase funding by 

$533 million between fiscal year 2005 and fiscal year 2009. In contrast, for 

the remaining 39 system acquisitions, FAA has reduced funding by $420 

million for this period. 

The planned increases in funding for these 14 major system acquisitions 

also come at the expense of other modernization activities outside the ATC 

modernization program, such as capital expenditures to replace aging ATC 

facilities that will house the system acquisitions. For example, FAA reports 

that it needs $2.5 billion (2005 dollars) annually to renew its aging physical 

infrastructure—assuming a $30 billion value of its assets and a 7- to 12-year 

useful life. According to the ATO, much of its physical infrastructure, 

including the buildings and towers that house costly ATC systems, is over 

30 years old and needs to be refurbished or replaced.54 However, FAA plans 

to reduce funding for facilities by nearly $790 million between fiscal year 

2005 and fiscal year 2009—a plan that runs counter to its reported need to 

refurbish or replace its physical infrastructure. Furthermore, FAA also 

plans to cut $1.4 billion from its spending plans for fiscal years 2005 

through 2009 for, among other things, new system acquisitions in the ATC 

modernization pipeline that do not yet have agency-approved cost, 

schedule, and performance targets or baselines (e.g., a new technology that 

would allow pilots to “see” the location of other aircraft on cockpit 

display).55

Our work has shown that FAA has taken some important steps to prioritize 

the 55 system acquisitions under its ATC modernization program. These 

54We have not verified FAA’s reported needs to refurbish or replace these structures/ 

facilities.

55Automatic Dependent Surveillance-Broadcast (ADS-B).
Page 32 GAO-05-331 National Airspace System

revised priorities are reflected in its most recent plans, which detail the 

areas where FAA plans to make cuts within its facilities and equipment 

budget to live within its expected means during fiscal years 2005 through 

2009. However, our work has also shown that these plans do not provide 

detailed information about the trade-offs that are underlie decisions to fully 

fund some systems and to defer, reduce, or eliminate funding for others and 

how these cuts will affect FAA’s modernization efforts, including what 

impact they will have on interdependent system acquisitions. To convey 

information to decision-makers on the impact of reduced funding on 

modernization, the ATO should detail its rationale and explicitly identify 

the trade-offs it is making to reach the administration’s budget targets, 

highlighting those programs slated for increased funding and those slated 

for reduced funding. Key information includes delayed benefits, the impact 

of cutting one ATC system acquisition on related or interdependent 

systems, and increased costs for maintaining legacy systems until new 

systems are deployed. Overall, the ATO needs to explicitly identify the 

implications of deferring, reducing, or cutting funding for a particular 

system or activity on the agency’s ability to modernize both the ATC system 

and related components of the NAS in the near, mid, and longer term. While 

funding deferrals, reductions, and cuts to ATC system acquisitions and 

related activities in FAA’s facilities and equipment budget may be beneficial 

and necessary in the long run, it is important for senior agency, department, 

OMB, and congressional decision-makers to have complete information to 

make informed decisions about the trade-offs that are being made when 

they consider annual budget submissions. 

As part of our research, we sought the perspective of an international 

group of experts, who also suggested that the ATO should provide the 

administration and Congress with detailed information in its budget 

submissions about the impact of reduced budgets on both ATC and NAS 

modernization.56 These experts were a part of an international panel of 

aviation experts we convened to address, among other issues, how federal 

56The panel consisted of foreign and domestic aviation experts from industry, government, 

private think tanks, and academia. Their fields of expertise included aviation safety, 

economics, and engineering; transportation research and policy; and government and 

private-sector management. Former FAA officials and current executives of the air traffic 

organizations in Canada and the United Kingdom were among the experts, as was the 

chairman of EUROCONTROL’s Performance Review Commission. GAO, Experts’ Views on 

Improving the U.S. Air Traffic Control Modernization Program, GAO-05-333SP

(Washington, D.C.: April 2005). 
Page 33 GAO-05-331 National Airspace System

budget constraints have affected ATC modernization and what steps the 

ATO could take in the short term to address these constraints.

For example, aviation experts emphasized the need for the ATO—which is 

now the organizational entity responsible for acquiring ATC systems—to 

prioritize its capital investments, as well as its investment in operating 

systems, with affordability in mind. These experts believe that the ATO 

needs to review all of its spending plans for modernization, determine 

which programs can realistically be funded, and select programs to cut. 

Moreover, they indicated that the ATO should have a mechanism to explain 

to Congress the implications that cutting one system has on other systems. 

For example, according to one of these experts, the current budget process 

tears apart a highly layered, interdependent system and does not reveal 

synergies between projects. Then, when the budget request goes to 

Congress, he said, “you have no opportunity to try to explain to anybody 

the interconnections of these programs.” As a result, when the 

appropriators decide not to fund a project, they may not understand how 

their decision will affect other projects. 

Conclusions The constrained budgetary environment makes it more important than ever 

for FAA to meet cost, schedule, and performance targets for each of the 

major ATC systems it continues to fund and to ensure that related 

activities, such as those to refurbish or replace the buildings that house 

ATC modernization systems, receive sufficient funding. The need for FAA 

to accommodate a 25 percent increase in demand for air travel over the 

next decade underscores the importance of these efforts. FAA has 

demonstrated a commitment to live within its expected means during fiscal 

years 2005 through 2009 by setting priorities among its ATC system 

acquisitions and identifying areas where it plans to cut funding. However, 

without detailed information about the trade-offs that underlie decisions to 

fully fund some systems and to defer, reduce, or eliminate funding for 

others, FAA’s plans do not allow senior agency, department, OMB, and 

congressional decision-makers to assess the implications of approving 

annual budget submissions for the ATC modernization program and related 

modernization activities that support more comprehensive efforts to 

modernize the NAS. 
Page 34 GAO-05-331 National Airspace System

Recommendation for 

Executive Action

To help ensure that key administration and congressional decision-makers 

have more complete information to assess the potential impact of annual 

budget submissions on individual ATC system acquisitions, the overall ATC 

modernization program, and related larger-scale NAS modernization 

activities funded through the facilities and equipment budget, we 

recommend that the Secretary of Transportation direct FAA to identify 

which activities under the ATC modernization program have had funding 

deferred, reduced, or eliminated and to provide detailed information about 

the impact of those decisions on FAA’s ability to modernize the ATC system 

and related components of the NAS in the near, mid, and longer term. This 

information should be reported to Congress annually.

Agency Comments We provided a copy of our draft report to DOT for review and comment. 

The draft was reviewed by officials throughout DOT and FAA, including the 

Vice President for Acquisition and Business Service. These officials 

provided comments through email. They generally agreed with the report 

and provided technical comments on specific aspects of the report, which 

we incorporated as appropriate. The FAA officials said they are continuing 

to consider our recommendation and indicated they would provide a 

response to it as required by 31 U.S.C. §720.

As agreed with your offices, unless you publicly announce the contents of 

this report earlier, we plan no further distribution until 30 days from the 

report date. At that time, we will send copies of this report to interested 

congressional committees, the Secretary of Transportation, and the 

Administrator, FAA. We will also make copies available to others upon 

request. In addition, the report will be available at no charge on the GAO 

Web site at http://www.gao.gov.

Please call me at (202) 512-2834 if you or your staff have any questions 

about this report. Contact points for our Offices of Congressional Relations 

and Public Affairs may be found on the last page of this report. Key 

contributors to this report are listed in appendix IV.

Gerald L. Dillingham, Ph.D.

Director, Physical Infrastructure Issues 
Page 35 GAO-05-331 National Airspace System

List of Congressional Requesters

The Honorable Tom Davis

Chairman

The Honorable Henry A. Waxman

Ranking Minority Member

Committee on Government Reform

House of Representatives

The Honorable Don Young

Chairman

The Honorable James L. Oberstar

Ranking Democratic Member

Committee on Transportation and Infrastructure

House of Representatives

The Honorable John L. Mica

Chairman

The Honorable Jerry Costello

Ranking Democratic Member

Subcommittee on Aviation

Committee on Transportation and Infrastructure

House of Representatives
Page 36 GAO-05-331 National Airspace System

Appendix I

Background and Status of FAA’s 16 Major Apendxies

System Acquisitions We Reviewed in Detail ApendxiI

Airport Surface 

Detection Equipment–

Model X (ASDE-X)

Figure 2: ASDE-X Screen Depicting an Airport Layout with Active Aircraft Targets

Note: Contractor for this system is Sensis Corporation.

Purpose and Status ASDE-X enables air traffic controllers to track the surface movement of 

aircraft and vehicles. It was developed to reduce runway incursions, 

reported as increasing from 186 in 1993 to 383 in 2001.1

 ASDE-X improves 

the ability of controllers to maintain awareness of the operational 

environment and to anticipate contingencies. The detection system 

automatically predicts potential conflicts and seamlessly covers airport 

runways, taxiways, and other areas. 

Source: Photo courtesy of FAA.

1

FAA defines runway incursion as any occurrence at an airport involving an aircraft, vehicle, 

person, or object on the ground that creates a collision hazard or results in a loss of 

separation between aircraft taking off, intending to take off, landing, or intending to land.
Appendix I

Background and Status of FAA’s 16 Major 

System Acquisitions We Reviewed in Detail

Page 37 GAO-05-331 National Airspace System

Figure 3: Changes to ASDE-X Schedule and Cost Targets

a

According to FAA officials, the change in cost target for ASDE-X was due to an increase in the scope 

of the project.

b

FAA plans to extend ASDE-X’s current deployment target from 2007 to 2009 because the project’s 

budgets were cut in fiscal years 2004 and 2005.

In June 2002, FAA decided to upgrade seven additional airports increasing 

the project’s total cost by $80.9 million. As of September 2004, FAA had 

placed three systems in operation and installed six others. FAA officials 

said they propose to extend the deployment baseline from 2007 to 2009 

because budgets were cut in fiscal years 2004 and 2005; in addition, internal 

and external funding was reprogrammed for other high-priority activities. 

The ASDE-X program office is working on alternative cost estimates and 

plans to present them to the Joint Resources Council by June 2005. 

0

100

200

300

400

500

600

2001 2002 2003 2004 2005 2006 2007 2008 2009

Deployment

adjustments

Estimated cost of

development

(dollars in millions)

Number of ASDE-X

systems

Initial schedule for deployment

Current schedule for deployment

424.3

510.2a

30

38 

0

10

20

30

40

Initial deployment

Final deployment

Initial Current Initial Current

Source: GAO presentation of FAA data.

b
Appendix I

Background and Status of FAA’s 16 Major 

System Acquisitions We Reviewed in Detail

Page 38 GAO-05-331 National Airspace System

Airport Surveillance 

Radar Model-11 (ASR11)

Figure 4: ASR-11 Equipment

Note: Contractor for this system is Raytheon.

Purpose and Status ASR-11 replaces aging analog radars, such as ASR-7 and ASR-8, with a 

single, integrated digital radar system. ASR-11 reduces operational costs, 

improves safety, and accommodates future capacity increases. ASR-11 also 

provides surveillance information to existing systems, such as the Standard 

Terminal Automation Replacement System (STARS) in terminal facilities 

and other systems in en route ATC facilities. As of March 2005, five sites 

have been commissioned into the NAS and five additional sites are in full 

operational capability. 

Source: Photo courtesy of FAA.
Appendix I

Background and Status of FAA’s 16 Major 

System Acquisitions We Reviewed in Detail

Page 39 GAO-05-331 National Airspace System

Figure 5: Changes to ASR-11 Schedule and Cost Targets

ASR-11 has experienced unplanned work, and the funding level received 

was less than the agency-approved funding level for the system acquisition; 

both factors contributed to schedule extensions and cost increases. FAA 

misjudged the extent to which the high-level requirements that were used 

to support the Department of Defense’s procurement of the commercialoff-the-shelf/nondevelopmental item (COTS/NDI) could result in a product 

capable of meeting FAA’s mission or user needs. As a result, unplanned 

software changes were required. The program requested $98.8 million for 

fiscal year 2004, based on the system’s acquisition program baseline, but 

received $74.3 million. In May 2004, FAA reprogrammed $2.35 million from 

ASR-11’s appropriated funds to the Essential Air Service.2

 Due to funding 

reductions, FAA decreased the number of ASR-11 systems to be purchased 

from 112 to 111. The 2005 request of $107.6 million was not approved; the 

reduction to $87.5 million may result in additional cost growth or the 

elimination of planned replacement sites. The ASR-11 program is 

scheduled to go to the Joint Resources Council in fiscal year 2005 to extend 

the program’s schedule to 2013 and to revise the baseline funding, primarily 

because of deferrals and budget reductions. As of March 2005, five sites 

have been commissioned into the NAS and five additional sites are fully 

operational.

0

25

50

75

100

125

1997 1999 2000 2001 2002 2003 2004 2005 1998 2006 2007 2008 2013

Deployment

adjustments

Estimated cost of

development 

(dollars in millions)

Number of facilities

receiving ASR-11

Initial schedule for deployment

Current schedule for deployment

743.3

916 112 111

Initial deployment

Final deployment

Initial Current Initial Current

Source: GAO presentation of FAA data.

0

200

400

600

800

1,000

2

The objective of the Essential Air Service program is to ensure that small communities that 

had received scheduled passenger air service before deregulation will continue to have 

access to the nation’s air transportation system.
Appendix I

Background and Status of FAA’s 16 Major 

System Acquisitions We Reviewed in Detail

Page 40 GAO-05-331 National Airspace System

Air Traffic Control 

Radar Beacon 

InterrogatorReplacement 

(ATCBI-6)

Figure 6: ATCBI-6 Screen Display Depicting All Transponder-Equipped Aircraft

Note: Contractor for this system is Raytheon.

Purpose and Status ATCBI-6 is part of the agency’s continuing effort to upgrade equipment to 

provide greater system capability and reliability that will, in turn, reduce 

operating costs. The ATCBI-6 replacement program will replace existing en 

route air traffic control beacon interrogator (ATCBI-4/5) equipment. The 

new ATCBI-6 radars will be able to determine both range and direction to 

and from aircraft, in addition to forwarding this information to the 

appropriate Air Route Traffic Control Centers’ automation systems. 

Source: Photo courtesy of FAA.
Appendix I

Background and Status of FAA’s 16 Major 

System Acquisitions We Reviewed in Detail

Page 41 GAO-05-331 National Airspace System

Figure 7: Changes to ATCBI-6 Cost and Schedule Targets

Funding reductions of $31.0 million for fiscal years 2002 and 2003 

contributed to the extension of ATCBI-6’s schedule. According to FAA, if 

funding reductions continue, further delays could occur with the system’s 

deployment, installation, and commissioning activities. As of September 

2004, the contractor has been meeting the new contract delivery schedule. 

0

50

100

150

200

1997 2000 2001 2002 2003 2004 2005 2006 1998 1999 2007 2008

Deployment

adjustments

Estimated cost of

development 

(dollars in millions)

Number of facilities

receiving ATCBI-6

Initial schedule for deployment

Current schedule for deployment

281.8 282.9

127 129

Initial deployment

Final deployment

Initial Current Initial Current

Source: GAO presentation of FAA data.

0

100

200

300
Appendix I

Background and Status of FAA’s 16 Major 

System Acquisitions We Reviewed in Detail

Page 42 GAO-05-331 National Airspace System

Advanced 

Technologies and 

Oceanic Procedures 

(ATOP) Figure 8: ATOP Equipment Reporting Aircraft Position Information

Note: Contractor for this system is Lockheed Martin.

Purpose and Status ATOP replaces aging oceanic ATC systems and procedures with an 

integrated system of new controller workstations, data-processing 

equipment, and software that will enhance the control and flow of oceanic 

air traffic to and from the United States. The system automatically updates 

information on an aircraft’s location and supersedes the current manual 

process. FAA controls oceanic air traffic at three sites: Anchorage, Alaska; 

New York, New York; and Oakland, California.

Source: Photo courtesy of FAA.
Appendix I

Background and Status of FAA’s 16 Major 

System Acquisitions We Reviewed in Detail

Page 43 GAO-05-331 National Airspace System

Figure 9: Changes to ATOP Schedule and Cost Targets

The ATOP program is operating within its cost, schedule, and performance 

targets. ATOP achieved its initial operational capability milestone in June 

2004. The contractor had originally agreed to a more aggressive 

development schedule in order to achieve this milestone by April 2003, or 

14 months earlier. FAA determined, however, that the contractor could not 

meet this accelerated date because of poor requirements development, 

unrealistic schedule targets, and inadequate estimation of software 

complexity. This exacerbated the scheduled transition from the current 

oceanic system to ATOP. Consequently, FAA spent an additional $4 million 

a year to operate and maintain the old system until ATOP is fully 

operational. According to FAA, the ATOP program office did not 

overspecify the operational and performance requirements; it wrote the 

technical document at a level that allowed the contractor to select the 

appropriate solutions and did not restrict design innovations. Yet, FAA’s 

internal documents revealed that the requirements were not adequately 

defined. For example, the ATOP Investment Analysis Study reported to the 

Joint Resources Council prior to the contract award that the lack of more 

detailed ATOP requirements at this stage of acquisition added risk and was 

of concern to the investment analysis team. 

According to FAA, the agency has taken steps to recognize the concerns 

identified by the ATOP Investment Analysis Study by maintaining 

requirements, encouraging controller participation, and robustly testing the 

system. FAA officials stated that the agency has developed a transition plan 

for the three sites. To accelerate the transition schedule and offset facility 

attrition, the ATOP program filled eight new controller positions at the New 

0

200

400

600

800

1,000

2001 2002 2003 2004 2005 2006 2007 2008

Deployment

adjustments

Estimated cost of

development

(dollars in millions)

Number of ATOP

systems

Initial schedule for deployment

Current schedule for deployment

548.2 548.2 3 3

Initial deployment

Final deployment

Initial Current Initial Current

Source: GAO presentation of FAA data.

0

1

2

3

4

5
Appendix I

Background and Status of FAA’s 16 Major 

System Acquisitions We Reviewed in Detail

Page 44 GAO-05-331 National Airspace System

York site and six at the Oakland site. In addition, ATOP training schedules 

are in place, and classes for FAA’s Air Traffic and Airway Facilities 

personnel are under way. Although the contractor’s costs to develop ATOP 

have grown by approximately $20 million, FAA is not responsible for 

payment because it has a fixed-price contract arrangement with the 

contractor. Yet, according to the Department of Transportation’s Inspector 

General, FAA would have to pay for all software problems after February 

28, 2005. After February 2005, Lockheed Martin will continue to work on 

software changes under the time and materials portion of the ATOP 

contract. FAA plans to maintain the acquisition program baseline 

milestones by relying on current contractor staffing and resources. FAA 

expects to conduct full transition exercises in June 2005 at the New York 

and Oakland sites.
Appendix I

Background and Status of FAA’s 16 Major 

System Acquisitions We Reviewed in Detail

Page 45 GAO-05-331 National Airspace System

Controller-Pilot Data 

Link Communications 

(CPDLC)

Figure 10: CPDLC Text Message on an Aircraft Display

Note: Contractor for this system is to be determined.

Purpose and Status CPDLC will allow pilots and controllers to transmit digital data messages 

directly between FAA automated ground computers and aircraft. By 

digitally transmitting routine air traffic control (ATC) messages between 

pilots and controllers, CPDLC will alleviate voice congestion, enhance ATC 

efficiency, and increase capacity by allowing controllers to handle more 

aircraft. FAA originally planned to implement CPDLC in several phases. 

Build 1, the initial development phase, was deployed in Miami for 2 years 

and consisted of four information services: initial contact, transfer of 

communications, altimeter setting, and predefined menu text. Build 1A 

would have added five additional services, including speed, altitude, and 

route clearance, but it was deferred by a Joint Resources Council decision 

in April 2003. Presently, FAA is conducting a preliminary investment 

analysis of National Build, which is intended to deploy the CPDLC system 

Source: Photo courtesy of FAA.
Appendix I

Background and Status of FAA’s 16 Major 

System Acquisitions We Reviewed in Detail

Page 46 GAO-05-331 National Airspace System

to all 20 Air Route Traffic Control Centers after they have implemented the 

En Route Automation Modernization (ERAM) program.

Figure 11: Changes to CPDLC Schedule and Cost Targets

CPDLC Build 1, implemented at Miami Air Route Traffic Control Center in 

October 2002, operated for 2 years. FAA’s acquisitions office had awarded 

the CPDLC Build 1A development contract before fully understanding the 

system’s requirements, including those of FAA’s aircraft certification office. 

Additionally, detailed interoperability requirements of air and ground 

equipment were not complete before the contract was awarded. According 

to FAA, additional CPDLC hardware, software, and other requirements 

increased costs by $69.8 million over the original baseline of $166.7 million. 

The revised cost target presented to the Joint Resources Council in April 

2003 was $236.5 million, about a 42 percent increase from its original cost 

target, for only 8 of the 20 proposed Build 1A locations. FAA decided to 

suspend acquisition of Build 1A because of concerns about the high costs 

of communications service provider messages, the uncertainty of 

integrating CPDLC with ERAM, and the ability of airlines to install, and 

benefit from, the CPDLC avionics equipment.

0

50

100

150

200

1999 2002 2003 2004 2005 2006 2007 2008 2000 2001 2009 2010

Deployment

adjustments

Estimated cost of

development

(dollars in millions)

Number of facilities

receiving CDPLC Build 1A

Initial schedule for deployment

Current schedule for deployment

166.7

20

Initial deployment

Final deployment

Initial Current Initial Current

Source: GAO presentation of FAA data.

0

5

10

15

20

25

30

Undetermined
Appendix I

Background and Status of FAA’s 16 Major 

System Acquisitions We Reviewed in Detail

Page 47 GAO-05-331 National Airspace System

En Route 

Communications 

Gateway (ECG)

Figure 12: ECG Maintenance Workstation Display

Note: Contractor for this system is Lockheed Martin.

Purpose and Status ECG replaces the interim Peripheral Adapter Module Replacement Item 

(PAMRI). Providing an interface from radar sites to en route centers, 

PAMRI has been operating for 10 years and has exceeded its life 

expectancy. The open and expandable platform of the ECG will allow for 

new connectivity and functionality as the NAS evolves.

Source: Photo courtesy of FAA.
Appendix I

Background and Status of FAA’s 16 Major 

System Acquisitions We Reviewed in Detail

Page 48 GAO-05-331 National Airspace System

Figure 13: Changes to ECG Schedule and Cost Targets

FAA is on schedule to complete ECG deployment in calendar year 2005. 

Tests revealed a weakness in security: limitations in designing the 

monitoring capability prevented appropriate monitoring unless a system 

technician remained logged on. To ensure that only authorized personnel 

had access to the system and that the monitoring could be done without a 

technician on-site, the ECG program office implemented a “guest” logon 

that enabled monitoring and prevented unauthorized access. According to 

FAA officials, correcting the weakness cost about $25,000, which falls 

within the program’s budget and schedule. An additional challenge 

concerns monitoring the ECG system from the System Operations Control 

(SOC)3

 positions. This issue may require SOC personnel to leave their posts 

if ECG requires some intervention to, among other things, discover why an 

event occurred. FAA is evaluating an improvement in the monitoring 

capability at the SOC positions. The estimated cost is $480,000, which falls 

within the program’s budget and schedule.

0

10

20

30

40

50

0

100

200

300

400

500

2002 2005 2006 2007 2003 2004

Deployment

adjustments

Estimated cost of

development

(dollars in millions)

Number of facilities

receiving ECG

Initial schedule for deployment

Current schedule for deployment

245.2 245.2 25 25

Initial deployment

Final deployment

Initial Current Initial Current

Source: GAO presentation of FAA data.

3

The System Operations Center (SOC) is the workspace on the operations control room 

floor where managers monitor the state of the equipment providing air traffic services.
Appendix I

Background and Status of FAA’s 16 Major 

System Acquisitions We Reviewed in Detail

Page 49 GAO-05-331 National Airspace System

En Route Automation 

Modernization (ERAM)

Purpose and Status Modular and expandable, ERAM will replace software and hardware in the 

host computers at FAA’s 20 en route air traffic control centers, which 

provide separation, routing, and advisory information. ERAM’s flight data 

processing capabilities will provide flexible routing around restrictions, 

such as congestion and weather. It will improve surveillance by increasing 

the number and types of surveillance sources, such as radars. ERAM will 

provide safety alerts to prevent aircraft collisions and congestion.

Figure 14: Changes to ERAM Schedule and Cost Targets 

ERAM has not breached schedule or cost parameters, but it remains a highrisk program because of its size and its amount of software code (more 

than 1 million lines). The contractor has reported that engineering costs are 

rising because of lower productivity than originally planned and an 

increase in the number of lines of software code. According to FAA 

officials, the contractor’s management reserve can absorb additional 

software development costs.

0

5

10

15

20

25

0

1

2

3

4

2003 2005 2006 2007 2008 2009 2010 2011 2004 2012 2013 2014 2015

Deployment

adjustments

Estimated cost of

development 

(dollars in billions)

Number of facilities

receiving ERAM

Initial schedule for deployment

Current schedule for deployment

2.15 2.15

20 20

Initial deployment

Final deployment

Initial Current Initial Current

Source: GAO presentation of FAA data.
Appendix I

Background and Status of FAA’s 16 Major 

System Acquisitions We Reviewed in Detail

Page 50 GAO-05-331 National Airspace System

Free Flight Phase 2 

(FFP2)

Figure 15: Free Flight Phase 2 User Request Evaluation Tool

Note: Contractors for this system are Computer Sciences Corporation, ITT, Lockheed Martin, and 

Metron.

Purpose and Status FFP2 builds on Free Flight Phase 1, which established the concept of 

managing air traffic in a way that enhances the safety, capacity, and 

efficiency of the NAS. Under FFP2, FAA expects air traffic control 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 while keeping air traffic controllers 

informed of such changes. FFP2 will allow controllers to manage pilot 

requests for flight information in en route airspace, identify and resolve 

possible mid-air conflicts up to 20 minutes in advance, and develop arrival 

sequence plans.

Source: Photo courtesy of FAA.
Appendix I

Background and Status of FAA’s 16 Major 

System Acquisitions We Reviewed in Detail

Page 51 GAO-05-331 National Airspace System

Figure 16: Changes to FFP2 Schedule and Cost Targets

According to FAA officials, the schedule delay in FFP2’s deployment from 

2006 to 2007 because, among other things, the funding level received was 

less than the agency-approved funding level for the system acquisition. 

Since the transition from Free Flight Phase 1 to Phase 2, the program has 

received less than the expected level of funding. For example, in fiscal year 

2003, FAA requested $107 million; however, due to external and internal 

budget cuts, the funding was reduced to $70 million.

0

10

20

30

40

50

0

200

400

600

800

1,000

2002 2005 2006 2007 2008 2009 2003 2004

Deployment

adjustments

Estimated cost of

development

(dollars in millions)

Number of facilities

receiving FFP2 systems

Initial schedule for deployment

Current schedule for deployment

546.2 546.2

21 21

Initial deployment

Final deployment

Initial Current Initial Current

Source: GAO presentation of FAA data.
Appendix I

Background and Status of FAA’s 16 Major 

System Acquisitions We Reviewed in Detail

Page 52 GAO-05-331 National Airspace System

FAA 

Telecommunications 

Infrastructure (FTI)

Figure 17: FTI Primary Network Operations Control Center

Note: Contractor for this system is Harris Corporation.

Purpose and Status FTI will replace costly networks of separately managed systems and 

services—both leased and owned—by integrating advanced 

telecommunications services within the NAS and non-NAS infrastructures. 

FTI will provide FAA with commercial telecommunications services that 

can meet present and future telecommunications needs between facilities. 

Its modern and reliable consolidated network will furnish multi-service 

capabilities. 

Source: Photo courtesy of FAA.
Appendix I

Background and Status of FAA’s 16 Major 

System Acquisitions We Reviewed in Detail

Page 53 GAO-05-331 National Airspace System

Figure 18: Changes to FTI Schedule and Cost Targets

FTI’s two-phase transition will take about 5 years to complete. Phase I was 

implemented at 21 Air Route Traffic Control Centers and 2 National 

Network Operations Control Centers. Deployment of Phase II, which is 

under way, will extend service to the remaining 4,477 NAS facilities. 

In June 2003, the FTI program returned to the Joint Resources Council with 

a proposed revision to the baseline that was based on actual contract 

prices for NAS operational services and estimated prices for mission 

support services. The council deferred revising the baseline until the 

program negotiated prices for mission support services. A consolidated 

Acquisition Program Baseline package for the full scope of NAS 

operational and mission support services was then completed in December 

2004. The Joint Resources Council approved the revised baseline on 

December 8, 2004.

1999 2002 2003 2004 2005 2006 2007 2008 2000 2001 2009 2010

Deployment

adjustments

Estimated cost of

development 

(dollars in millions)

Number of facilities

receiving FTI

Initial schedule for deployment

Current schedule for deployment

205.7

310.2

4,500 4,500

Initial deployment

Final deployment

Initial Current Initial Current

Source: GAO presentation of FAA data.

0

2,000

4,000

6,000

8,000

10,000

0

100

200

300

400
Appendix I

Background and Status of FAA’s 16 Major 

System Acquisitions We Reviewed in Detail

Page 54 GAO-05-331 National Airspace System

Integrated Terminal 

Weather System 

(ITWS)

Figure 19: ITWS Situation Display

Note: Contractor for this system is Raytheon.

Purpose and Status ITWS furnishes air traffic controllers and supervisors with full-color 

graphic displays of weather information concerning airport terminal 

airspace within a 60-mile radius. It provides a comprehensive current 

weather situation and precise forecasts of expected weather conditions for 

the next 60 minutes. ITWS requires no meteorological interpretation by air 

traffic controllers or pilots. 

Source: Photo courtesy of FAA.
Appendix I

Background and Status of FAA’s 16 Major 

System Acquisitions We Reviewed in Detail

Page 55 GAO-05-331 National Airspace System

Figure 20: Changes to ITWS Schedule and Cost Targets

a

FAA initially projected that its first ITWS deployment would occur between September 2001 and 

August 2002 and that final system deployment would occur between January 2003 and July 2003.

ITWS experienced delays because its software development was complex 

and the funding level received was less than the agency-approved funding 

level for the system acquisition. The program appeared to be progressing 

according to its baseline; however, immediately after the critical design 

review in September 1998, the contractor revealed that the program had 

exceeded the target cost by $4 million. Consequently, ITWS experienced 

schedule delays and cost increases, along with performance shortfalls. 

In May 2004, FAA’s Joint Resources Council revised the baseline for the 

ITWS program to include, in production, the capability to predict weather 

conditions 60 minutes into the future. Because of constrained funding, the 

ATO Executive Council froze funding for fiscal years 2005, 2006, and 2007. 

In addition, FAA postponed deploying 12 of the 34 systems until an 

undefined future date. In January 2005, FAA management decided that the 

ITWS program would use already-procured equipment to install the next 

six sites and transition to Airport Improvement Program grants for the 

remaining scheduled sites. The ITWS program office is currently studying 

the impact of the decision on the system’s baseline. According to the 

contractor and the original acquisition plan, all systems were scheduled for 

delivery by December 2001, but that date has now been extended to after 

2009. 

0

10

20

30

40

50

1997 1999 2000 2001 2002 2003 2004 2005 1998 2006 2007 2008 2009

Deployment

adjustments

Estimated cost of

development 

(dollars in millions)

Number of facilities

receiving ITWS

Initial schedule for deploymenta

Current schedule for deployment

276.1 286.1

34 34

Initial deployment

Final deployment

Initial Current Initial Current

Source: GAO presentation of FAA data.

0

100

200

300
Appendix I

Background and Status of FAA’s 16 Major 

System Acquisitions We Reviewed in Detail

Page 56 GAO-05-331 National Airspace System

Local Area 

Augmentation System 

(LAAS)

Figure 21: Key Components of LAAS

Note: Contractor for this system is Honeywell.

Purpose and Status LAAS will allow aircraft to execute precision instrument approaches and 

landings in all weather conditions. Its global positioning system will 

broadcast highly accurate information to aircraft in a flight’s final phases, 

providing more precise approach paths than the current instrument landing 

system, reducing the required separation between incoming aircraft, and 

increasing airspace capacity. LAAS will also provide airports with precision 

approach capability for all runways, eliminating the need for multipleinstrument landing system installations. 

Source: Photo courtesy of FAA.
Appendix I

Background and Status of FAA’s 16 Major 

System Acquisitions We Reviewed in Detail

Page 57 GAO-05-331 National Airspace System

Figure 22: Changes to LAAS Schedule and Cost Targets

For LAAS, three of the four factors we discussed have contributed to the 

system’s cost increases, schedule extensions, and performance problems. 

Specifically, poorly established requirements resulted in the addition of 113 

new requirements to the initial specification, entailing unplanned work 

including significant software and hardware changes. In addition, FAA 

underestimated LAAS’ software complexity because it inadequately 

assessed the system’s technology maturity. In particular, the agency 

misunderstood the potential for radio interference through the 

atmosphere, which could limit LAAS’ operations. FAA also did not fully 

engage technical experts early in the approval process of LAAS. According 

to the Department of Transportation Inspector General, although FAA has 

had a LAAS Integrity Panel in place since 1996 to assist with its research 

and development activities, the panel was not formally tasked with 

resolving the integrity requirement4

 early in the approval process, which 

might have enabled FAA to develop a quicker solution.5

 In 2003, FAA 

focused the LAAS Integrity Panel on developing a solution to meet the 

integrity requirement. 

1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2011

Deployment

adjustments

Estimated cost of 

development

(dollars in millions)

Number of LAAS

systems

Initial schedule for deployment

Current schedule for deployment unknown

530.1

696.1

160

143

0

40

80

120

160

200

Initial Current Initial Current

Initial deployment

Final deployment

Source: GAO presentation of FAA data.

0

100

200

300

400

500

600

700

4

The system’s integrity requirement alerts pilots of erroneous information not more often 

than once every 47 years, or 10-7.

5

Department of Transportation’s Inspector General, FAA Needs to Reset Expectations for 

LAAS Because Considerable Work Is Required before It Can Be Deployed for Operational 

Use, AV-2003-006 (Dec. 16, 2002).
Appendix I

Background and Status of FAA’s 16 Major 

System Acquisitions We Reviewed in Detail

Page 58 GAO-05-331 National Airspace System

The contractor has experienced difficulties ensuring that the system will 

alert pilots when it produces erroneous information. FAA and the 

contractor agree that these difficulties have resulted from a lack of 

communication. When the contract was awarded, FAA assumed that LAAS 

was 80-percent developed but later discovered that only about 20 percent 

was complete. FAA therefore suspended funding in fiscal year 2005 and 

used the remaining $18 million to resolve the integrity requirement 

problem, among other things, in fiscal year 2004. Although FAA had not 

requested funding, Congress did approve an additional $10 million for 

LAAS in fiscal year 2005. The FAA will continue to work on resolving LAAS 

integrity and safety assurance issues during fiscal year 2005. During fiscal 

year 2006, the program office will develop a business case justification on 

whether to continue the LAAS program.
Appendix I

Background and Status of FAA’s 16 Major 

System Acquisitions We Reviewed in Detail

Page 59 GAO-05-331 National Airspace System

Next Generation Air-toGround 

Communication 

(NEXCOM) Figure 23: Multimode Digital Radio

Note: Contracter for this system is ITT (segiment 1A).

Purpose and Status NEXCOM will improve air traffic control communications by replacing 

controller-pilot analog communication with a state-of-the-art digital 

system. Consisting of multimode digital radios, avionics, and ground 

stations, NEXCOM will enhance security by requiring digital authentication 

and preventing “phantom controllers” from gaining access to the 

communications system. NEXCOM Segment 1A will replace 30- to 40-yearold radios, deploying 12,000 new radio sets that use analog and digital 

communications with aircraft. Segment 1B will create ground stations to 

communicate with aircraft equipped with digital capability. 

Source: Photo courtesy of FAA.
Appendix I

Background and Status of FAA’s 16 Major 

System Acquisitions We Reviewed in Detail

Page 60 GAO-05-331 National Airspace System

Figure 24: Changes to NEXCOM Schedule and Cost Targets

NEXCOM experienced schedule slippages in developing Segment 1A—the 

multimode radio sets—because the vendor failed to meet interference 

requirements and to perform additional tests to avoid risks associated with 

future upgrades. FAA’s initial plans did require meeting interference 

requirements. The initial schedule assumed FAA could procure a 

nondevelopmental item (NDI) product that met the interference 

requirements. The vendor’s product did not meet the established 

interference requirements. A solution had to be developed and tested. The 

project schedule had to be adjusted to accommodate additional 

development and testing. As a result, the system’s approval was delayed by 

about 20 months. In September 2003, NEXCOM Segment 1A was initially 

deployed at Jacksonville, Florida. Segment 1A cost and schedule baseline is 

scheduled for a Joint Resources Council review in August 2005.

NEXCOM’s cost growth has resulted from additional software and 

hardware requirements. Because the funding level received was less than 

the agency-approved funding level for the system acquisition, FAA 

postponed funding Segment 1B—the ground stations—until at least fiscal 

year 2008. FAA has no current estimate for the last deployment date. 

FAA plans to develop and deploy NEXCOM Segment 2 between 2008 and 

2013. This segment will provide a digital data link to aircraft at high and 

super-high altitudes. Segment 3, scheduled between 2011 and 2013, will 

provide digital voice and data link capabilities throughout the ATC system. 

FAA has not developed funding estimates for these two segments.

0

3,000

6,000

9,000

12,000

15,000

0

200

400

600

800

1,000

1998 2000 2001 2002 2003 2004 2005 2006 1999 2007 2008

Deployment

adjustments

Estimated cost of

development

(dollars in millions)

Number of NEXCOM

radiosets

Initial schedule for deployment

Current schedule for deployment

405.7

986.4

12,000 12,000

Initial deployment

Final deployment

Undetermined

Initial Current Initial Current

Source: GAO presentation of FAA data.
Appendix I

Background and Status of FAA’s 16 Major 

System Acquisitions We Reviewed in Detail

Page 61 GAO-05-331 National Airspace System

NAS Infrastructure 

Management System—

Phase 2 (NIMS-2)

Figure 25: NIMS Infrastructure

Note: Contractor for this system is Digicon.

Purpose and Status NIMS, a centralized maintenance management system, will operate and 

maintain the NAS infrastructure, including its facilities, systems, and 

equipment (e.g., communications, radars, and navigational aids). NIMS will 

decrease the number of en route delays by reducing the time required to 

restore systems to full operation following maintenance. NIMS—Phase 1 

Source: Photo courtesy of FAA.
Appendix I

Background and Status of FAA’s 16 Major 

System Acquisitions We Reviewed in Detail

Page 62 GAO-05-331 National Airspace System

currently provides initial Operational Control Center capability,6 along with 

remote monitoring and control functionality, to 3,700 NAS facilities and 

5,800 deployed maintenance data terminals. By fully implementing 

resource management and enterprise management software, NIMS—Phase 

2 will focus on increasing workforce productivity in such priority activities 

as receiving orders and managing resources. Future NIMS phases will 

allow for information sharing that is in sync with NAS’ technological 

improvements.

Figure 26: Changes to NIMS–Phase 2 Schedule and Cost Targets

According to FAA, the funding for NIMS–Phase 2 was $96.4 million below 

the approved amount in agency planning documents. Subsequently, FAA 

had to defer additional system requirements, extend the schedule by 5 

years, and increase the system’s cost estimate by $84.0 million. FAA is 

revising the baseline for Phase 2, as shown in figure 26; a Joint Resources 

Council decision is planned for August 2005.

6

Operational Control Center capability, established in 2001, is a standard set of tools and 

procedures needed to open the control centers. The tools provide the initial enterprise 

management and resource management technical capabilities needed at Operational 

Control Centers.

0

50

100

150

200

2000 2003 2004 2005 2006 2007 2008 2009 2001 2002 2010 2011 2011

Deployment

adjustments

Estimated cost of

development 

(dollars in millions)

Number of facilities

receiving NIMS

Initial schedule for deployment

Current schedule for deployment

172.9 172.9

Initial deployment

Final deployment

Initial Current Initial Current

N/A N/A

Source: GAO presentation of FAA data.
Appendix I

Background and Status of FAA’s 16 Major 

System Acquisitions We Reviewed in Detail

Page 63 GAO-05-331 National Airspace System

Operational and 

Supportability 

Implementation 

System (OASIS) Figure 27: OASIS Dual Screen Display

Note: Contractors for this system are Harris Corporation (OASIS workstations) and Evans Corporation 

(consoles), respectively.

Purpose and Status OASIS, a modified commercial-off-the-shelf system, replaces workstation 

consoles, among other things, at automated flight service stations. It also 

replaces the Flight Services Automation system for which spare parts and 

hardware support have been difficult for FAA to maintain. OASIS furnishes 

up-to-the-minute weather graphics by integrating real-time weather and 

flight planning data with overlays of flight routes. It also provides 

operational support, retrieves reports, and supplies lightning data and icing 

images, among other things.

Source: Photo courtesy of FAA.
Appendix I

Background and Status of FAA’s 16 Major 

System Acquisitions We Reviewed in Detail

Page 64 GAO-05-331 National Airspace System

Figure 28: Changes to OASIS Schedule and Cost Estimates

OASIS has experienced schedule extensions and cost increases because of 

unplanned work, insufficient stakeholder involvement, and funding that is 

less than the agency had approved as needed for meeting the system’s 

schedule, cost, and performance targets. For example, the system 

acquisition schedule slipped because of a larger-than-planned development 

effort. FAA’s 1998 review of the contractor system’s architecture for OASIS 

revealed that the commercial-off-the-shelf solution was not as mature as 

FAA had envisioned when the contract was awarded and revealed that the 

contractor’s commercial products did not fully satisfy its requirements. 

According to the Department of Transportation’s Inspector General, FAA 

had identified a number of significant human factors concerns, such as 

inadequate weather graphics. This indicated that stakeholders were not 

sufficiently involved throughout the system’s design and development. As a 

result, FAA eliminated the option of commercial-off-the-shelf procurement. 

In addition, the OASIS program was rebaselined in March 2000 due to fiscal 

year 2000 appropriations being reduced to $10 million from the $21.5 

million baseline. The reduction in funding resulted in a reduced rate of 

software development, delayed and reduced the rate of planned hardware 

and console deployments, and resulted in the incremental deployment of 

operational software. This contributed to FAA’s delay of its first-site 

implementation from July 1998 to 2002. 

According to FAA officials, receiving less funding than the agency had 

approved for fiscal years 2004 and 2005 also resulted in a delay in OASIS’ 

deployment to automated flight service stations. As of February 2005, FAA 

had deployed 19 systems: 16 at Automated Flight Service Stations (AFSS) 

0

10

20

30

40

50

60

70

0

25

50

75

100

125

150

175

200

1997 1999 2000 2001 2002 2003 2004 2005 1998 2006

Deployment

adjustments

Estimated cost of

development 

(dollars in millions)

Number of OASIS

systems

Initial schedule for deployment

Current schedule for deployment

174.7

155.5

64

19

Initial deployment

Final deployment

Initial Current Initial Current

Source: GAO presentation of FAA data.
Appendix I

Background and Status of FAA’s 16 Major 

System Acquisitions We Reviewed in Detail

Page 65 GAO-05-331 National Airspace System

and 3 at other sites. Software upgrades that are under way will be 

completed by June 2005. FAA had no plans for installations or software 

upgrades beyond those at the AFSS sites, pending an evaluation of privatesector bids to operate flight service stations. Until then, FAA had directed 

the program to remain within the funding levels of its Capital Investment 

Plan for fiscal years 2004 to 2006.7

 According to FAA, since completion of 

the evaluation of bids in February 2005, OASIS’ implementation remains 

unchanged. FAA does not plan on additional OASIS funding for software 

enhancements or more installations. FAA plans to phase out OASIS 

between March 2006 and March 2007 in accordance with the new service 

provider’s transition plan.

7

The Capital Investment Plan, a 5-year financial plan, allocates funds to NAS projects on the 

basis of a detailed analysis of project funding by FAA functional working groups. The plan 

includes estimates for the current fiscal year budget and for 4 future year expenditures for 

each line item in the facilities and equipment budget.
Appendix I

Background and Status of FAA’s 16 Major 

System Acquisitions We Reviewed in Detail

Page 66 GAO-05-331 National Airspace System

Standard Terminal 

Automation 

Replacement System 

(STARS) Figure 29: STARS Controller Workstation

Note: Contractor for this system is Raytheon.

Purpose and Status STARS—a joint program of FAA, the Department of Defense (DOD), and 

the Department of Transportation (DOT)—replaces aging FAA and DOD 

terminal systems with state-of-the-art terminal air traffic control systems. 

The system is designed to prevent duplication of development and logistic 

costs. Civil and military air traffic controllers use STARS to direct aircraft 

near major U.S. airports. Its open and expandable terminal automation 

platform can accommodate air traffic growth, as well as new hardware and 

software that promote safety, maximize operational efficiency, and improve 

controllers’ productivity. 

Source: Photo courtesy of FAA.
Appendix I

Background and Status of FAA’s 16 Major 

System Acquisitions We Reviewed in Detail

Page 67 GAO-05-331 National Airspace System

Figure 30: Changes to STARS Schedule and Cost Targets

a

This estimate includes development costs only and does not include technology refresh and terminal 

automation enhancement. 

b

Based on the May 2004 FAA approved Acquisition Program Baseline for development and 

procurement estimates.

c

The February 1996 baseline included limited human factor evaluations and a basic commercial-offthe-shelf configuration. 

FAA revised its baseline for the STARS program in May 2004, changing the 

acquisition to a phased approach that divides large programs into smaller 

phases to allow the agency to evaluate other alternatives of system 

implementation. For Phase 1, STARS was approved for deployment to 51 

Terminal Radar Approach Control (TRACON) facilities. Following the 

system’s release and FAA’s concurrence with the November 23, 2004, report 

from the DOT Inspector General, FAA reduced STARS’ deployment to 47 

TRACON facilities. STARS is fully operational at 29 FAA terminal radar 

control facilities and 21 DOD radar control facilities. If approved in 2005, 

DOD plans to deploy STARS to 106 Radar Approach and Control 

(RAPCON) facilities and 75 towers nationally and worldwide. With 

completion of DOD’s transition in 2004 to FAA’s new STARS’ configuration, 

both DOD and FAA are operating together on a single national software and 

hardware configuration baseline. 

During STARS’ development, schedule slippages and cost increases 

occurred because the original commercial-off-the-shelf (COTS) acquisition 

strategy focused on early adoption of commercial technology by FAA and 

DOD could avoid the increasing cost of supporting legacy systems by 

quickly deploying STARS to the highest-priority air traffic control facilities, 

and then making further improvements. FAA had compressed STARS’ 

1996 1999 2000 2001 2002 2003 2004 2005 1997 1998 2006 2007 2008

Deployment

adjustments

Estimated cost of

developmenta

(dollars in billions)

Number of facilities

receiving STARS

Initial schedule for deployment

Current schedule for deployment

0

.25

.50

.75

1.00

1.25

1.50

.94

1.46b

0

40

80

120

160

200 172

47 

Initial deployment

Final deployment

Initial Current Initial Current

Source: GAO presentation of FAA data.

c
Appendix I

Background and Status of FAA’s 16 Major 

System Acquisitions We Reviewed in Detail

Page 68 GAO-05-331 National Airspace System

original development and testing schedule from 32 to 25 months, leaving 

only limited time for human factors evaluations. Allowing insufficient time 

to involve stakeholders, FAA and the contractor had to restructure the 

contract to address technicians’ and controllers’ concerns, including an 

inconsistency in visual warning alarms and color codes between the old 

and the new systems. However, the STARS initial system configuration was 

satisfactory for use by DOD as deployed. The FAA modified the COTS 

strategy and suspended STARS deployments until FAA controller and 

technician requirements were developed. FAA estimates the COTS 

acquisition strategy, which limited involvement of controllers and 

maintenance technicians in the system’s development added 3 years and 

$500 million to the development of more than 160 system requirements. 

The first phase of the three-phase deployment plan comprises 47 systems. 

FAA and the DOT are currently determining a safe, economical, and 

affordable site mix for follow-up phases.
Appendix I

Background and Status of FAA’s 16 Major 

System Acquisitions We Reviewed in Detail

Page 69 GAO-05-331 National Airspace System

Wide Area 

Augmentation System 

(WAAS)

Figure 31: Key Components of WAAS

Note: Contractor for this system is Raytheon.

Purpose and Status WAAS uses global positioning system satellites to provide precise 

navigation and landing guidance to aircraft at all airports, including 

thousands that have no ground-based instrument landing capability. WAAS 

also provides safer and more efficient arrival, en route, and departure 

operations by allowing user equipment to augment the global positioning 

system while increasing its position accuracy and reliability, among other 

things. 

Source: Photo courtesy of FAA.
Appendix I

Background and Status of FAA’s 16 Major 

System Acquisitions We Reviewed in Detail

Page 70 GAO-05-331 National Airspace System

Figure 32: Change to WAAS Schedule and Cost Targets

a

September 1999 and May 2004 estimates for WAAS development exclude $1.3 billion in satellite 

communications leases. 

When WAAS has full operating capability, it will provide en route 

navigation guidance from the surface up to 100,000 feet and instrument 

landing guidance down to 200 feet. It currently provides full en route 

navigation up to 100,000 feet and instrument landing guidance down to 250 

feet at all qualified airports in the continental United States. FAA has begun 

to publish WAAS instrument flight procedures for some runways; however, 

pilots cannot use WAAS for landing guidance on those runways for which 

FAA has not written guidance. To achieve full operating capability, a 

second civil aviation frequency must be added to new global positioning 

system satellites to allow aircraft to conduct precision runway approach 

operations during ionospheric interruptions, such as “solar storms.” The 

Department of Defense, which is responsible for providing this frequency, 

plans to add it between 2013 and 2019.

FAA encountered cost, schedule, and performance problems because its 

scheduling was accelerated, coordination among its offices proved 

insufficient, and technical challenges delayed its meeting the integrity 

requirement—a requirement that pilots be alerted in a timely manner when 

the system should not be used. At the urging of government and aviation 

industry groups in the early 1990s, FAA accelerated WAAS’ schedule by 

attempting to develop, test, and deploy the system within 28 months, even 

though software development alone was expected to take 24 to 28 months. 

Rather than shortening the total development time, these steps contributed 

to schedule delays. FAA also set development milestones before 

0

500

1,000

1,500

2,000

2,500

1994 1999 2000 2001 2002 1995 1996 1997 1998 2003 2004 2005 2013

Deployment

adjustments

Estimated cost of

development 

(dollars in millions)

Satellite lease for WAAS 

(dollars in millions)

Initial schedule for deployment

Current schedule for deployment

Initial operating capability

Full operating capability

Initial Current Initial Current

509

1,304

2,036a

0

500

1,000

1,500

2,000

2,500

Source: GAO presentation of FAA data.
Appendix I

Background and Status of FAA’s 16 Major 

System Acquisitions We Reviewed in Detail

Page 71 GAO-05-331 National Airspace System

completing the research and development required to prove WAAS’ 

capability. Since officials on WAAS’ integrated product development team 

within the aircraft certification office did not participate regularly during 

design and development, FAA did not recognize its difficulty in meeting the 

integrity requirement or its lack of scientific and technical expertise. FAA 

eventually acquired the expertise, and a team of satellite navigation experts 

solved the problem. These actions resulted in unplanned work and 

contributed to the rise in WAAS’s cost from the original estimate of $509 

million in 1994 to $2.036 billion in 2005, and to a 6-year extension in its 

commissioning date. According to FAA, adding 6 years to the program’s life 

cycle also contributed to increased costs.8

8

FAA also transferred $1.3 billion--the cost of satellite leases--from the operations account to 

the facilities and equipment account, bringing the total estimate at completion cost to $3.3 

billion.
Page 72 GAO-05-331 National Airspace System

Appendix II

Information on the 39 Additional Systems 

under the ATC Modernization Program ApendxiI

Table 4: Cost and Schedule Information for Nine Additional Major Systems under the ATC Modernization Program

Dollars in millions

Program/system description

Original

cost

target

Current

cost

target

1st year 

funded

Last year 

funding 

planned

Original 

schedule 

initial 

deployment 

target

Current 

schedule 

initial 

deployment 

target

Original 

schedule 

last 

deployment 

target

Current 

schedule 

last 

deployment 

target

HOST/Oceanic Computer 

System Replacement 

(HOCSR): Replaces the main 

ATC computer processor and 

some peripherals and ensures 

supportability of other 

peripherals until replaced by 

ERAM. 

$424.10 $368.50 FY 97 FY 05 December 

1998

December 

1998

June 2004 April 2004 

En Route System 

Modification: Will replace 

obsolete components, upgrade 

controllers’ displays and 

supporting infrastructure, and 

configure consoles to 

accommodate additional 

processors. 

$201.90 $201.90 FY 00 FY 09 N/A N/A May 2009 N/A 

Initial Academy Training 

System (IATS): Enables the 

training of an increasing 

number of new air traffic 

controllers at the FAA 

Academy. 

$23.35 $23.35 FY 03 FY 08 September 

2005

September 

2005

September 

2005

September 

2005 

Ultra High Frequency (UHF) 

Radio Replacement: 

Replaces aging equipment 

used to communicate with 

Department of Defense aircraft 

in support of military 

operations. 

$85.15 $85.15 FY 01 Beyond 

FY 09

FY 03 FY 10 FY 10 FY 10

Command Center 

Conference Control System 

(CCS) - Replace Operational 

Telephone Voice Switch 

(OTS): Replaces the existing 

telephone system at the FAA 

Air Route Control System 

Command Center in Herndon, 

Va. The existing telephone 

system is becoming 

unsupportable and can no 

longer perform required 

functions. 

$12.70 $12.70 FY 02 FY 05 FY 05 FY 05 FY 05 FY 05 
Appendix II

Information on the 39 Additional Systems 

under the ATC Modernization Program

Page 73 GAO-05-331 National Airspace System

Source: GAO presentation of FAA data.

Program/system description

Original

cost

target

Current

cost

target

1st year 

funded

Last year 

funding 

planned

Original 

schedule 

initial 

deployment 

target

Current 

schedule 

initial 

deployment 

target

Original 

schedule 

last 

deployment 

target

Current 

schedule 

last 

deployment 

target

Capstone Phase I (a part of 

the Safe Flight 21 program): 

A demonstration program, 

intended to improve aviation 

system safety in Alaska 

through the introduction of new 

communications, navigation, 

and surveillance technologies, 

as well as improving aviation 

system capacity and efficiency. 

$18.55 $18.55 N/A N/A FY 00 N/A FY 03 N/A 

Automated Surveillance 

Radar-Model 9 (ASR-9)/Mode 

Service Life Extension 

(SLEP): Extends the service 

life of the radar by replacing 

obsolete components to 

sustain existing system 

capabilities, such as providing 

aircraft detection and 

separation services to reduce 

aircraft delays and improve 

safety at congested airports.

$186.50 $186.50 FY 01 Beyond 

FY 09

TBD TBD TBD TBD 

Aviation Surface Weather 

Observation Network 

(ASWON): A suite of five 

weather systems that provides 

automated surface weather 

observation to meet the needs 

of pilots, operators, and air 

traffic controllers. 

$350.90 $403.80 FY 98 Beyond 

FY 09

September 

2002

N/A September 

2010

N/A 

Precision Runway Monitor 

(PRM): An electronic scan 

radar that tracks and 

processes aircraft targets at a 

1-second update rate and 

allows simultaneous 

approaches on runways 

spaced less than 4,300 feet 

apart, thereby increasing 

capacity and reducing delays 

during adverse weather 

conditions. 

$145.80 $145.80 FY 88 FY 07 October

1997

October

1997

January 

2007

January

 2007 

(Continued From Previous Page)

Dollars in millions
Appendix II

Information on the 39 Additional Systems 

under the ATC Modernization Program

Page 74 GAO-05-331 National Airspace System

Table 5: Cost and Schedule Information for the 30 Buy-It-by-the-Pound Systems under the ATC Modernization Program

Dollars in millions

Program/system description

Appropriated

funding for 1st

year

Appropriated

funding

through FY 04

1st year 

funded

Last year 

funding 

planned

1st initial 

operating 

capability/ 

operational 

readiness 

date

Last initial 

operating 

capability/ 

operational 

readiness date

En Route Enhancements: Maintains 

current software systems and supports 

development, integration, and 

implementation of upgrades to, among 

other things, the Host software. 

$5.30 $36.50 FY 01 Beyond 

FY 09

N/A N/A

Terminal Sustainment: Will maintain 

the existing FAA terminal automation 

systems, such as Common Automated 

Radar Terminal System (CARTS) 

ARTS IIEs and IIIEs, until the Terminal 

Automation Modernization and 

Replacement program replaces or 

upgrades the systems.a

$6.30 $73.60 FY 00 Beyond 

FY 09

N/A N/A

Current Enhanced Traffic 

Management System (ETMS) OPS:

Maintains and supports mission-critical 

traffic flow management (TFM) 

operations in 85 ATC facilities and 

makes necessary upgrades to support 

enhanced traffic management services. 

$13.40 $116.50 FY 98 FY 05 N/A N/A

Traffic Flow Management 

Infrastructure (TFM-I)

Modernization: Modernizes the TFM 

decision support systems and tools that 

help balance growing flight demands 

with NAS capacity within an 

environment. 

$8.50 $30.40 FY 02 Beyond 

FY 09

February 

2008

N/A

Departure Spacing Program (DSP): 

Assists controllers in the more efficient 

management of departures from 

multiple airports within the New York 

and Philadelphia metropolitan areas. 

$7.50 $48.50 FY 01 FY 06 Prior to FY 03 Prior to FY 03

NAS Resources/Notice to Airmen 

(NOTAM): Provides an automated, 

centralized, standardized, and timely 

distribution system for NOTAMS using a 

dedicated telecommunications network. 

$1.70 $10.90 FY 04 Beyond 

FY 09

N/A N/A
Appendix II

Information on the 39 Additional Systems 

under the ATC Modernization Program

Page 75 GAO-05-331 National Airspace System

Program/ system description

Appropriated

funding for 1st

year

Appropriated

funding

through FY 04

1st year 

funded

Last year 

funding 

planned

1st initial 

operating 

capability/ 

operational 

readiness 

date

Last initial 

operating 

capability/ 

operational 

readiness date

Voice Switching and Control System 

(VSCS)b

: Upgrade and tech refresh to 

ensure that the air-to-ground and 

ground-to-ground communications 

capabilities are reliable and available 

for separating aircraft, coordinating 

flight plans, and transferring information 

between en route ATC facilities. 

$13.60 $60.00 FY 01 Beyond 

FY 09

October 2006 N/A

Weather Message Switching Center 

Replacement (WMSCR) Transition:

Will upgrade obsolete processors, 

output devices, display screens, backup 

systems and software. This will allow 

pilots quick and accurate access to 

weather data and NOTAMS.

$2.50 $8.50 FY 01 FY 05 N/A N/A

Enhanced Terminal Voice Switch 

(ETVS): Replaces obsolete voice 

switches in the ATC Towers and 

Terminal Radar Approach Control 

facilities. Voice switches enable air 

traffic controllers to communicate with 

aircraft as well as other ATC facilities. 

$2.00 $95.40 FY 95 FY 09 May 1998 N/A

Communications Facilities 

Expansion (CFE): Provides a vehicle 

for facilities to improve communications 

coverage to meet specific operational 

requirements based upon, among other 

things, air traffic demand. 

$6.00 $53.00 FY 91 Beyond 

FY 09

N/A N/A

Air/Ground Communications Radio 

Frequency Interference (RFI) 

Elimination: Provides equipment to 

improve air and/or ground 

communications and provides support 

for remote communication facilities. 

The equipment will reduce the need for 

inter-modulation products, thus 

eliminating the major source of radio 

frequency interference at congested 

sites. 

$1.20 $26.40 FY 89 Beyond 

FY 09

1st delivery on 

current 

contract June 

1996

Ongoing

(Continued From Previous Page)

Dollars in millions
Appendix II

Information on the 39 Additional Systems 

under the ATC Modernization Program

Page 76 GAO-05-331 National Airspace System

Program/ system description

Appropriated

funding for 1st

year

Appropriated

funding

through FY 04

1st year 

funded

Last year 

funding 

planned

1st initial 

operating 

capability/ 

operational 

readiness

date

Last initial 

operating 

capability/ 

operational 

readiness date

Critical Telecommunications 

Support (CTS): Enables FAA to 

nationally manage programmed, 

unprogrammed, and emergency 

telecommunications network 

requirements for the NAS. 

$9.90 $63.00 FY 89 FY 05 N/A N/A

Recovery Communications 

(RCOM ) - Command and Control 

Communications (C3): Provides FAA 

with the minimum command-andcontrol communications capability 

necessary to direct the management, 

operation, and reconstruction of the 

NAS during regional or local 

emergencies when normal common 

carrier communications are interrupted. 

C3 also provides minimum capabilities 

for continuity of operations for FAA.

$6.30 $51.10 FY 92 Beyond 

FY 09

June 2003 N/A

Aeronautical Data Link (ADL) - Flight 

Information Service (FIS): Provides 

data link broadcasts of graphic and text 

flight information service data to the 

cockpit that are consistent with 

information available to air traffic 

controllers and flight service specialists 

in the NAS. 

$3.30 $8.50 FY 99 FY 08 June 2000 N/A

Tower Data Link Services (TDLS): 

Displays the clearances received from 

Air Route Traffic Control Centers 

(ARTCC) to the tower, distributes flight 

plan data, weather information, and 

general information messages from the 

ARTCC National Airspace Center 

computer to ARTCC printers and Air 

Traffic Control Towers (ATCT) remote 

sites. In addition, the system displays 

weather information received via ATCT 

weather interface. 

$2.30 $10.80 FY 00 FY 05 Tech refresh

start May 

2002

N/A

(Continued From Previous Page)

Dollars in millions
Appendix II

Information on the 39 Additional Systems 

under the ATC Modernization Program

Page 77 GAO-05-331 National Airspace System

Program/ system description

Appropriated

funding for 1st

year

Appropriated

funding

through FY 04

1st year 

funded

Last year 

funding 

planned

1st initial 

operating 

capability/ 

operational 

readiness

date

Last initial 

operating 

capability/ 

operational 

readiness date

Voice Recorder Replacement 

Program (VRRP): Replaces a total of 

530 aging analog systems with modern 

digital systems that will reduce both lifecycle maintenance costs and 

maintenance staffing requirements.

$3.60 $24.80 FY 97 Beyond 

FY 09

January 1996 N/A

Houston Area Air Traffic System 

(HAATS): Provides the focal point and 

support for infrastructure, national 

airspace improvements, and 

implementation of the new procedures 

and airspace design for the Houston 

area.

$12.00 $52.10 FY 01 FY 08 N/A N/A

Instrument Landing Systems (ILS):c

Provides precision guidance 

(horizontal, vertical, and distance) 

information to allow category I, II, and 

III landing approaches at large and 

medium airports. 

$5.70 $455.30 FY 89 Beyond 

FY 09

April 1995, 

February 2007

N/A

Visual Navaids for New Qualifiers: 

Procures and installs visual 

navigational aids approach lighting 

systems to enhance landing 

capabilities at designated airports 

throughout the United States.

$9.80 $40.90 FY 93 Beyond 

FY 09

June 2006 N/A

Approach Lighting System 

Improvement (ALSIP) Continuation: 

Retrofits rigid lighting systems with 

lightweight and low-impact resistant 

structures that collapse or break apart 

at impact, thereby reducing damage to 

aircraft that may strike these structures 

during departure or landing. 

$5.80 $183.20 FY 93 Beyond 

FY 09

September 

1996

N/A

Visual Navaids-Sustain, Replace, 

Relocate: Replaces aging, obsolete 

visual navigational aids and other 

ground-based navigation and landing 

aids to maintain current en route, 

approach, and landing capabilities at 

various airports throughout the United 

States. 

$3.00 $6.00 FY 02 Beyond 

FY 09

N/A N/A

(Continued From Previous Page)

Dollars in millions
Appendix II

Information on the 39 Additional Systems 

under the ATC Modernization Program

Page 78 GAO-05-331 National Airspace System

Program/ system description

Appropriated

funding for 1st

year

Appropriated

funding

through FY 04

1st year 

funded

Last year 

funding 

planned

1st initial 

operating 

capability/ 

operational 

readiness

date

Last initial 

operating 

capability/ 

operational 

readiness date

Very High Frequency Omnidirectional Range (VOR) Collocated 

with Tactical Air Navigation 

(VORTAC): Replaces, relocates, or 

converts VORTAC facilities used for 

aerial navigation. General aviation, 

commercial carriers, and other groups 

use this navigation capability for en 

route navigation and approach 

operations into airports. 

$1.60 $27.00 FY 93 Beyond 

FY 09

NA N/A

Runway Visual Range (RVR) - 

Replacement/Establishment: 

Replaces aging, maintenanceintensive, and difficult-to-support RVR 

legacy systems. Pilots receive critical 

meteorological visibility data that are 

used to decide whether it is safe to take 

off or land when visibility is limited. 

$2.80 $42.50 FY 98 Beyond 

FY 09

N/A N/A

Sustain Distance Measuring 

Equipment (DME): Replaces older 

DME, which is difficult and expensive to 

maintain because replacement parts 

are largely unavailable, and provides 

current technology electronics to 

improve operations and facilities 

performance. 

$1.20 $13.90 FY 99 Beyond 

FY 09

August 2003 N/A

Long Range Radars (LRR) 

Improvements - Infrastructure 

Upgrades: Sustains and improves 

LRRs, many of which are over 50 years 

old, and require upgrades to prevent 

outages and reduce maintenance 

costs. 

$1.00 $20.20 FY 00 FY 09 N/A N/A

Runway Incursion Reduction 

Program (RIRP) - ATDP: Provides 

research, development, and 

operational evaluation of technologies 

to improve runway safety. 

$1.40 $35.40 FY 99 Beyond 

FY 09

N/A N/A

(Continued From Previous Page)

Dollars in millions
Appendix II

Information on the 39 Additional Systems 

under the ATC Modernization Program

Page 79 GAO-05-331 National Airspace System

Source: GAO presentation of FAA data.

a

Terminal Automation Modernization and Replacement program is intended to replace aging 

automation and display systems at the Nation’s terminal air traffic control facilities.

b

The VSCS tech refresh does not have a baseline; an investment analysis is pending. 

c

The April 1995 operational readiness data (ORD) is under the original contract, while the new contract 

will be in effect in fiscal year 2006. Additional systems added in appropriations may affect the last 

ORD.

Program/ system description

Appropriated

funding for 1st

year

Appropriated

funding

through FY 04

1st year 

funded

Last year 

funding 

planned

1st initial 

operating 

capability/ 

operational 

readiness 

date

Last initial 

operating 

capability/ 

operational 

readiness date

Automatic Dependent SurveillanceBroadcast (ADS-B): Broadcasts 

derived aircraft position data from an 

onboard navigation system such as 

global navigation satellite system 

thereby allowing pilots and air traffic 

controllers to “see” location of nearby 

aircraft and engage in collaborative 

decisionmaking. 

$3.50 $14.30 FY 99 FY 09 N/A N/A

Next Generation Weather Radar 

(NEXRAD) Open Systems Upgrades: 

Detects, processes, distributes, and 

displays hazardous and routine 

weather information on air traffic 

controller consoles. 

$2.00 $32.90 FY 98 FY 06 February 2000 N/A

Terminal Doppler Weather Radar 

(TDWR) – Service Life Extension 

Program (SLEP): Maintains the 

current level of service until 2020 and 

improves deteriorating system 

reliability. The service provides air 

traffic controllers with reports of 

hazardous windshear and other severe 

weather in and near an airport's 

terminal approach and departure zone 

at higher-density airports with high 

occurrences of thunderstorms. 

$3.30 $3.30 FY 03 FY 09 September 

2004

N/A

Corridor Integrated Weather System 

(CIWS): Will improve airspace capacity 

during adverse weather in congested 

airspace. The key approach is to 

provide accurate and timely prediction 

of hazardous weather activity. 

$5.00 $9.10 FY 02 Beyond 

FY 09

N/A N/A

(Continued From Previous Page)

Dollars in millions
Page 80 GAO-05-331 National Airspace System

Appendix III

Objectives, Scope, and Methodology ApendxiI

We examined (1) FAA’s experience in meeting cost, schedule, and/or 

performance targets for major system acquisitions under its ATC 

modernization program, (2) the steps FAA has taken to address longstanding challenges with the ATC modernization program and additional 

steps that are needed, and (3) the potential effects of the constrained 

budget environment on FAA’s ability to modernize the ATC system.

To address the first objective, we selected 16 of the 55 system acquisitions 

in the ATC modernization program to review in detail.1

 We selected these 

16 systems in July 2004, when this review was still a part of our broader 

work on FAA’s efforts to modernize the National Airspace System (NAS).2 

Specifically, we selected the 16 ATC system acquisitions with the largest 

life-cycle costs that met the following criteria: each system had cost, 

schedule, and/or performance targets, was discussed in our prior and 

Department of Transportation Inspector General reports, had not been 

fully implemented or deployed by 2004, and received funding in 2004. We 

reviewed this list with FAA officials to ensure that we did not exclude any 

significant system.3

 (See app. I for additional information on these 16 

systems.) FAA does not have a formal definition of major systems under its 

Acquisition Management System; however, agency officials told us that if a 

system acquisition has a formally approved baseline, we could consider it 

“major.” Using this definition, we determined that 25 of the 55 system 

acquisitions under the ATC modernization program are major. The 

remaining 30 system acquisitions are generally what FAA refers to as buy-itby-the-pound systems that are commercially available and ready to use 

without modification, such as those to replace a system that has reached 

the end of its useful life. 

For fiscal year 2005, the 55 systems accounted for about 55 percent of 

FAA’s facilities and equipment (F&E) budget, or $1.38 billion of the $2.52 

billion appropriated for the F&E budget. The 16 major systems accounted 

for 36 percent ($917.3 million), and the other 39 system acquisitions 

accounted for about 19 percent ($460 million). The remaining 45 percent of 

1

According to FAA officials, the number of system acquisitions in the ATC modernization 

program can vary annually, when Congress earmarks funds for a specific system acquisition. 

As of March 2005, the number of system acquisitions under the program was 55. 

2

Our review of FAA’s NAS modernization efforts will be issued later this year.

3

To make the report as current as possible, we have used fiscal year 2005 funding levels 

where appropriate, including the status sheets for each of the 16 systems in appendix I. 
Appendix III

Objectives, Scope, and Methodology

Page 81 GAO-05-331 National Airspace System

the F&E budget will be spent on facilities, mission support, and personnelrelated activities ($1.14 billion).

To assess the 16 major system acquisitions, we relied largely on data 

collected from FAA and contracting officials for two engagements we 

issued in November 2004 on FAA’s acquisition and certification processes.4

In turn, we updated this information and collected data on the remaining 39 

systems under the modernization program, primarily through interviews 

with FAA officials and analyses of the data they provided, including key 

acquisition documents.(See app. II for additional information on these 39 

system acquisitions.) In addition, we reviewed our past reports and those 

of the Department of Transportation’s Inspector General. Furthermore, we 

interviewed FAA officials within the recently created ATO and collected 

and analyzed the documents they provided. We also interviewed officials 

with the Aircraft Owners and Pilots Association, Air Transport Association, 

Department of Defense, National Air Traffic Controllers Association, and 

RTCA.5

 Furthermore, we convened a panel of international aviation 

experts6 to obtain their views on, among other things, the factors that have 

affected the cost, schedule, and/or performance of FAA’s ATC 

modernization program. 

In addition, we assessed the reliability of FAA’s cost and schedule 

estimates. Through interviews with FAA officials about their data system 

and quality controls, we determined that the cost and schedule estimates 

were appropriate for use in our report. Specifically, the estimates are 

sufficiently authoritative, appropriate, and reliable to allow us to use them 

without conducting any further assessment. The estimates appear to be 

based on reasonable assumptions. Our review did not focus on FAA’s 

efforts to modernize its facilities. 

4

GAO, Air Traffic Control: FAA Needs to Ensure Better Coordination When Approving Air 

Traffic Control Systems, GAO-05-11 (Washington, D.C.: Nov. 17, 2004); GAO, Air Traffic 

Control: FAA’s Acquisition Management Has Improved, but Policies and Oversight Need 

Strengthening to Help Ensure Results, GAO-05-23 (Washington, D.C.: Nov. 12, 2004).

5

Organized in 1935 and once called the Radio Technical Commission for Aeronautics, RTCA 

is today known just by its acronym. RTCA is a private, not-for-profit corporation that 

develops consensus-based performance standards for ATC systems. RTCA serves as a 

federal advisory committee, and its recommendations are the basis for a number of FAA’s 

policy, program, and regulatory decisions.

6

GAO, Experts’ Views on Improving the U.S. Air Traffic Control Modernization Program, 

GAO-05-333SP (Washington, D.C.: April 2005). 
Appendix III

Objectives, Scope, and Methodology

Page 82 GAO-05-331 National Airspace System

To address the second objective, we interviewed FAA officials, primarily 

within the recently created ATO, and collected and analyzed the documents 

they provided. We also interviewed officials with the Aircraft Owners and 

Pilots Association, Air Transport Association, Department of Defense, 

National Air Traffic Controllers Association, and RTCA.

We also reviewed past GAO reports and those of the Department of 

Transportation’s Inspector General. In addition, we obtained the views of 

the international aviation experts who participated in our panel on what 

steps the ATO could take in the short term to address the factors that have 

affected the cost, schedule, and/or performance of FAA’s ATC 

modernization program.

To address the third objective, we interviewed officials within FAA’s ATO 

and obtained and analyzed data on FAA’s capital investments and annual 

budgets. We also interviewed officials with other organizations cited above. 

In addition, we obtained the views of the international aviation panelists on 

how federal budget constraints have affected ATC modernization and what 

steps the ATO could take in the short term to address these constraints. We 

conducted our review from November 2004 through May 2005 in 

accordance with generally accepted government auditing standards.
Page 83 GAO-05-331 National Airspace System

Appendix IV

GAO Contact and Staff Acknowledgments ApendxiIV

GAO Contact Gerald L. Dillingham, Ph.D. (202) 512-2834

Staff 

Acknowledgments

In addition to the person named above, Beverly L. Norwood, Tamera 

Dorland, Seth Dykes, Elizabeth Eisenstadt, Brandon Haller, Bert Japikse, 

Maren McAvoy, and Ed Menoche made key contributions to this report.

(540096)
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