NATIONAL 

AIRSPACE SYSTEM

Improved Budgeting

Could Help FAA 

Better Determine 

Future Operations and 

Maintenance Priorities 

Report to Congressional Requesters

August 2013

GAO-13-693

United States Government Accountability Office
United States Government Accountability Office

Highlights of GAO-13-693, a report to 

congressional requesters

August 2013

NATIONAL AIRSPACE SYSTEM 

Improved Budgeting Could Help FAA Better

Determine Future Operations and Maintenance 

Priorities 

Why GAO Did This Study

Through the NextGen initiative, FAA

plans to transform the current groundbased radar air-traffic control system to 

a system based on satellite navigation, 

automated position reporting, and 

digital communications. The NextGen 

transition will be a complex, multi-year, 

incremental process. Decisions 

affecting how long the transition will 

take and the number of existing 

systems that will remain in operation 

during the transition have implications 

for FAA’s existing systems, workforce, 

facilities, and budget. 

GAO was asked to continue monitoring

the progress and challenges 

associated with the NextGen transition 

and implementation. In this report, 

GAO examined (1) FAA’s progress in 

addressing key challenges affecting its 

ability to execute the NextGen 

transition; (2) the performance and 

condition of current air traffic control 

system and facilities; (3) FAA’s efforts 

to address maintenance requirements 

of its current systems and facilities; 

and (4) the extent to which FAA has 

planned for the financial resources for 

sustaining existing systems and 

facilities and the NextGen transition. In 

doing so, GAO analyzed FAA system 

performance data and documents and 

interviewed FAA officials and aviation 

stakeholders. 

What GAO Recommends

To improve FAA’s efforts to manage 

the transition, GAO recommends that 

FAA develop a strategy to improve 

planning of its operations budget and 

ensure sufficient data are available to 

support these efforts. DOT did not 

agree or disagree with this

recommendation but provided 

technical comments.

What GAO Found

The Federal Aviation Administration (FAA) has made some progress in 

addressing key challenges as it begins the gradual transition to the Next 

Generation Air Transportation System (NextGen). It has filled key leadership 

positions and developed tools to manage interdependent NextGen programs. 

FAA is working to address other identified challenges, including incentivizing 

aircraft operators to equip with NextGen technologies, identifying workforce roles

under NextGen, and realigning and consolidating facilities. However, FAA has 

yet to make some decisions needed to move forward with these efforts. For 

example, FAA is evaluating realignment options to help realize efficiencies but 

has not yet identified which facilities will be consolidated or realigned. 

FAA reports that operational availability of current air traffic control systems at 

the largest airports has exceeded 99 percent, and underlying data suggest 

increasing maintenance requirements for current systems and facilities, some of 

which may have to operate for many more years during the NextGen transition. 

For example, from fiscal years 2001 through 2012, planned, or scheduled, 

system outages doubled while unscheduled outages increased 45 percent, an 

increase due, in part, to the age and deteriorating condition of existing systems.

FAA data on facilities and infrastructure condition, although limited, also suggest

potentially increasing maintenance requirements. FAA is working to establish a 

new performance measure to publicly report on system condition and replace the 

operational availability measure, which was discontinued in 2012. 

Recognizing that FAA’s cost estimates for maintaining existing systems and 

facilities and implementing NextGen exceed anticipated funding levels, the 

agency is developing a plan to address its system and facilities maintenance

issues, which it expects to complete by September 2013. In developing the plan, 

it recognizes that many unstaffed facilities, such as shelters and communication

towers, face deteriorating conditions that can put employees maintaining these 

facilities at risk of injury. However, the process used to collect condition data 

does not facilitate an agency-wide priority assessment, as each location 

established its own priorities. Thus, FAA cannot target its limited resources on 

those projects in greatest need of repair and most critical to the national airspace 

system. FAA is also working to retire systems that are no longer needed as 

NextGen capabilities are deployed but will need to overcome challenges in 

securing stakeholder buy-in and funding. 

FAA’s budget planning does not fully account for future operations and 

maintenance needs and priorities of existing and NextGen systems. While FAA’s 

capital plan identifies priorities based on 5-year funding projections, better data 

on FAA infrastructure could help prioritize competing resource demands of 

existing systems and facilities and NextGen deployment. FAA data on life-cycle 

operations and maintenance costs give some indication of future requirements, 

but FAA has not determined how these costs might be paid for, particularly if it 

has to maintain a growing number of existing systems as NextGen is deployed. 

FAA has identified improvements needed for its operations budget process and 

proposed to develop a 5-year operations plan that better links capital investments 

with future operations costs, but has yet to institute these improvements. View GAO-13-693. For more information, 

contact Gerald L. Dillingham at (202) 512-

2834 or dillinghamg@gao.gov. 
Page i GAO-13-693 National Airspace System

Letter 1 

Background 2

FAA Has Made Progress in Addressing Key Transition Challenges, 

but Significant Issues Remain to Be Addressed to Realize 

NextGen Benefits 9

Existing System Performance Remains High, but the Reported 

Measure Is Insufficient to Determine Overall System Condition 20

FAA’s Efforts to Develop a Long-term Systems and Facilities 

Maintenance Strategy Could Be Hampered by Limited Data on 

Condition 28

FAA’s Budget Process Lacks Sufficient Data to Determine Future 

Operations and Maintenance Needs and Priorities 33

Conclusions 44

Recommendation for Executive Action 46

Agency Comments 46

Appendix I Scope and Methodology 50

Appendix II Status of NextGen Acquisition Programs, as of June 2013 52

Appendix III GAO Contact and Staff Acknowledgments 53

Tables

Table 1: FAA Workforce, Facilities, and Systems and Unstaffed 

Infrastructure Supporting and Operating in the National 

Airspace System, 2012 3

Table 2: The Federal Aviation Administration’s (FAA) Capital Plan 

and Deferred Maintenance Levels for Selected Unstaffed 

Air Traffic Control Infrastructure and Systems 27

Table 3: Status of NextGen Programs with Baselined Segments 52

Table 4: Status of NextGen Programs without Baselined Segments 52

Contents 
Page ii GAO-13-693 National Airspace System

Figures

Figure 1: Examples of NextGen Changes and Benefits 5

Figure 2: Current Federal Aviation Administration (FAA) 

Organizational Structure with Next Generation Air 

Transportation (NextGen) Responsibilities 7

Figure 3: Annual Reported Performance Measure for Air Traffic 

Control System Operational Availability for 30 Airports 

with the Most Activity, Actual and Target, Fiscal Years 

2004–2011 22

Figure 4: Number of Systems and System Outages throughout the 

National Airspace System, Fiscal Years 2001–2012 23

Figure 5: Very High Frequency Omnidirectional Radio Range (VOR) 

Station 31

Figure 6: Estimated and Actual Facilities and Equipment Funding 

Levels for NextGen and Existing Systems, Fiscal Years 

2007–2017 34

Figure 7: Federal Aviation Administration’s Planned Transition for 

Surveillance Capabilities, 2012 36

Figure 8: The Federal Aviation Administration’s (FAA) Enacted 

Budget Authority for the Operations Account Fiscal Years 

2000–2013 38

Figure 9: The Federal Aviation Administration’s (FAA) Projected 

Operations and Maintenance Costs for Baselined Existing 

and NextGen Programs, Fiscal Years 2013–2017 and 2018 

and Beyond 40

Figure 10: The Federal Aviation Administration’s (FAA) Operations 

Funding and the Air Traffic Organization’s (ATO) Portion 

of This Funding, Fiscal Year 2012 42
Page iii GAO-13-693 National Airspace System

Abbreviations

ADS-B Automatic Dependent Surveillance Broadcast

AIP Airport Improvement Program

ATO Air Traffic Organization

CIP Capital Investment Plan 

CRS Congressional Research Service

DME Distance Measuring Equipment

DOD Department of Defense

DOT Department of Transportation

FAA Federal Aviation Administration 

GSA General Services Administration

JPDO Joint Planning and Development Office

JRC Joint Resources Council

I2I Ideas to In-Service 

ICF Integrated Control Facility

ILS instrument landing system 

LCMS Learning Content Management System

NAS National Airspace System

NATCA National Air Traffic Controllers Association

NextGen Next Generation Air Transportation System

NGIP NextGen Implementation Plan

OEP Operational Evolution Partnership

OMB Office of Management and Budget

PASS Professional Aviation Safety Specialists

PMO Program Management Office

RTCA Radio Technical Commission for Aeronautics

TRACON terminal radar approach control

VOR VHF omnidirectional radio range 

VHF very high frequency

This is a work of the U.S. government and is not subject to copyright protection in the 

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Page 1 GAO-13-693 National Airspace System

441 G St. N.W.

Washington, DC 20548

August 22, 2013

Congressional Requesters

Through the Next Generation Air Transportation System (NextGen) 

initiative, the Federal Aviation Administration (FAA) plans to transform the 

current ground radar-based air-traffic control system to a system based 

on satellite navigation, automated position reporting, and digital 

communications. After almost a decade since Congress directed FAA to 

conceptualize and plan the initiative, the agency has been moving from 

planning to initial implementation of NextGen systems. The transition to 

NextGen—which encompasses multiple programs, procedures, and 

systems at different levels of maturity—will be a complex, incremental, 

multi-year process. Since 2006, we have monitored FAA’s development 

of NextGen and identified a number of key challenges facing the agency’s 

efforts to implement the transition. For example, we have reported that 

various investment and policy decisions, including what existing air traffic 

control systems and facilities will remain in the national air space system 

during the transition and for how long, have yet to be made.1

You requested that we continue to monitor the progress and challenges 

associated with the transition and implementation of NextGen. In 

response, this report addresses: (1) FAA’s progress in addressing 

challenges we have identified that affect its ability to execute the 

For the 

systems and facilities that remain, FAA will have to monitor and maintain 

their performance and condition while the agency coordinates and 

implements the NextGen transition. In addition, some new systems that 

are being, or were scheduled to be, implemented to support the transition 

have experienced costly delays, which may require FAA to maintain 

existing systems and facilities longer than originally anticipated. 

Uncertainty about how long the transition will take and how long existing 

systems will remain in operation also has implications for FAA’s workforce 

and facilities, including how and to what extent FAA will continue to train 

employees on aging air traffic control systems and facilities as well as on 

new NextGen systems, procedures, and upgraded facilities.

 

1

GAO, Integration of Current Implementation Efforts with Long-term Planning for the Next 

Generation Air Transportation System, GAO-11-132R (Washington, D.C.: Nov. 22, 2010) 

and Next Generation Air Transportation System: FAA Faces Implementation Challenges, 

GAO-12-1011T (Washington, D.C.: Sept. 12, 2012).

 
 

Page 2 GAO-13-693 National Airspace System

transition to NextGen, including preparing its workforce and facilities; (2) 

changes in the performance and condition of current air traffic control 

systems and facilities from 2001 through 2012; (3) FAA’s efforts to 

address maintenance requirements of its current systems and facilities; 

and (4) the extent to which FAA has planned for the financial resources to 

sustain existing systems and facilities during the NextGen transition. To 

address these four objectives, we reviewed agency-provided 

documentation, including NextGen planning documents such as the 2012 

and 2013 NextGen Implementation Plans, internal reports related to the 

agency’s NextGen initiatives, air traffic control system performance and 

condition data, and FAA process and procedure documentation. We 

interviewed FAA officials from multiple offices within the NextGen 

Organization and Air Traffic Organization who have a key role in 

implementing NextGen, as well as those from offices responsible for 

maintaining the existing systems and facilities. We also interviewed a 

variety of stakeholders and experts with knowledge and experience 

related to NextGen implementation, including industry associations, the 

air traffic controllers union, and the bargaining unit representing the 

airway transportation system specialists—whom we refer to as 

technicians in this report. We conducted this performance audit from 

January 2012 through August 2013 in accordance with generally 

accepted government auditing standards. Those standards require that 

we plan and perform the audit to obtain sufficient, appropriate evidence to 

provide a reasonable basis for our findings and conclusions based on our 

audit objectives. We believe that the evidence obtained provides a 

reasonable basis for our findings and conclusions based on our audit 

objectives. For more information on our scope and methodology, see 

appendix I.

FAA’s primary mission is to provide the safest, most efficient aerospace 

system in the world. This system, known as the national airspace system, 

handles over 50,000 flights a day and more than 700 million passengers 

each year. As table 1 shows, FAA operates and maintains this system 

through (1) the FAA workforce that operates and maintains the NAS, 

including approximately 6,000 technicians and 14,000 air traffic 

controllers who work in airport towers, terminal areas, en route centers, 

oceanic air traffic control centers, and other facilities, and (2) air traffic 

control and other supporting systems and infrastructure, including groundBackground 

Workforce and 

Infrastructure in 

the Current National 

Airspace System
 

Page 3 GAO-13-693 National Airspace System

based surveillance radar facilities, communication equipment, and 

automation systems and facilities that house and support these systems.

Table 1: FAA Workforce, Facilities, and Systems and Unstaffed Infrastructure Supporting and Operating in the National 

Airspace System, 2012

Number

FAA workforce

FAA air traffic controllers 15,454

FAA technicians 6,076

Other FAA employees 25,501

Total workforce 47,031

FAA staffed facilities 

En route control centers 23

Terminal radar approach facilities and towersa 402

Other staffed facilitiesb 148

Total staffed facilities 573c

FAA systems and unstaffed infrastructure

Navigation systems and infrastructured 13,484

Surveillance systems and infrastructuree 1,742

Communications systems and infrastructuref 18,903

Weather systems and infrastructureg 2,268

Other infrastructureh 23,536

Mission supporti 4,344

Automation systemsj 2,293

Total systems and unstaffed infrastructure 66,570

Source: FAA Facility, Service, and Equipment Profile database and FAA Administrator’s Fact Book, June 2012.

a

This number includes the 106 federal contract tower owned by the government but does not include 

the 137 federal contract towers that are owned by airport sponsors.

b

This number includes government-owned facilities at the FAA Mike Monroney Aeronautical Center 

and William J. Hughes Technical Center as well as government-owned facilities that FAA uses under 

occupancy agreement with the General Services Administration (GSA).

c

This number does not include the other staffed facilities that FAA leases or that GSA leases on 

behalf of FAA for FAA staff.

d

This number includes various navigation systems, such as the 1,500 instrument landing systems and 

967 very high frequency omnidirectional radio range (VOR) systems.

e

This number includes FAA’s radar systems, including 100 long-range radar systems, 250 terminal

radar systems, and 50 surface surveillance radar systems.

f

This number includes a wide range of communication systems, such as the 750 very high 

frequency/frequency modulation digital communication systems and nearly 500 voice recording 

systems.

g

This number includes various weather systems, such as the 1,900 surface weather observation 

systems and 35 integrated weather systems.
 

Page 4 GAO-13-693 National Airspace System

h

This number includes 2,400 support shelters and 3,400 fuel storage tanks.

i

This number includes supporting infrastructure and systems, such as 380 closed circuit television 

systems.

j

Automation systems include the En Route Automation Modernization systems being installed in each 

of the 23 en route centers.

In 2003, recognizing the need for a transformation of the national 

airspace system, Congress directed FAA to conceptualize and plan 

NextGen.2

 

2

Vision 100—Century of Aviation Reauthorization Act, Pub. L. No. 108-176, § 709, 117 

Stat. 2490, 2582-2585 (2003). Vision 100 directed the creation of the Joint Planning and 

Development Office (JPDO) within FAA to create and carryout an integrated plan for 

developing NextGen and to facilitate collaboration between FAA and other federal 

agencies involved in the effort. In addition to FAA, federal partner agencies include the 

Departments of Commerce, Defense, Homeland Security, and Transportation; the 

National Aeronautics and Space Administration (NASA); and the White House Office of 

Science and Technology Policy.

NextGen was envisioned as a major redesign of the air 

transportation system to increase efficiency, enhance safety, and reduce 

flight delays that would entail precision satellite navigation and 

surveillance; digital, networked communications; an integrated weather 

system; and more. Figure 1 provides examples of changes and benefits 

that are expected to come from NextGen. This complex undertaking 

requires acquiring new integrated air-traffic control systems; developing 

new flight procedures, standards, and regulations; and creating and 

maintaining new supporting infrastructure. This transformation is 

designed to dramatically change the roles and responsibilities of both air 

traffic controllers and pilots and change the way they interface with their 

systems. In addition, the transformation requires FAA to have a sufficient 

number of skilled technicians to ensure that both the existing and new 

systems are properly maintained and certified throughout the transition. 

The involvement of airlines and other aviation stakeholders is also critical 

since full implementation of NextGen will necessitate investment by 

airlines and others in new technologies.

FAA’s Transition 

to NextGen
 

Page 5 GAO-13-693 National Airspace System

Figure 1: Examples of NextGen Changes and Benefits

Notes: The baseline reflects an aircraft’s flight path in the current air-traffic control system. 

“Four-dimensional (4-D) trajectory” operations is an air traffic management concept in which every 

aircraft that is operating in or managed by the air traffic control system is represented in four 

dimensions—latitude, longitude, altitude, and with time. 

a

Automatic Dependent Surveillance-Broadcast (ADS-B) is a technology that enables aircraft to 

continually broadcast flight data—such as position, air speed, and altitude— among other types of 

information, to air traffic controllers and other aircraft.

FAA has a number of plans outlining the actions needed to execute the 

transition to NextGen over the next decade. Within these plans are 

decision points regarding which existing systems and facilities will remain 

in service and for how long. For example, FAA expects that as NextGen

technologies come online, it will be able to make decisions in 2016 on 

whether to reduce some of the current predominant navigation aids in the 
 

Page 6 GAO-13-693 National Airspace System

national airspace system—the instrument landing systems (ILS).3 In 

another example, FAA has begun developing new air-traffic control voice 

communication infrastructure to replace its current inventory of 12 

different voice switches. According to its plans, FAA expects to make 

decisions in the 2017—2019 timeframe on when it might be able to 

discontinue use of some of the existing voice switches.

Various offices within FAA are involved in NextGen development and 

implementation (see fig. 2). FAA’s Deputy Administrator is responsible for 

overseeing NextGen implementation and is supported by the Assistant 

Administrator for NextGen, who is responsible for planning and 

integrating NextGen systems and procedure deployment. The Air Traffic 

Organization (ATO) is responsible for the operations and maintenance of 

the air-traffic control system as well as implementing and managing 

NextGen programs and is led by the Chief Operating Officer, who is 

supported by 8 vice presidents responsible for different aspects of the airtraffic control system. One such vice president heads the Program 

Management Organization, which was created within ATO in 2011 to 

centralize oversight over all FAA program development, including 

NextGen programs. The Joint Planning and Development (JPDO) 

Director reports to the Deputy Administrator and is responsible for longterm NextGen vision and coordinating and collaborating across the 

federal government on cross-cutting NextGen issues, such as the 

integration of unmanned aerial systems in the national airspace system. 

Beyond these key leadership positions, successful NextGen 

implementation requires involvement of offices throughout FAA to 

facilitate the acquisition of integrated NextGen systems and the 

development of flight procedures, aircraft performance capabilities, and 

supporting infrastructure.

 

3

An Instrument Landing System (ILS) provides aircraft with precision vertical and 

horizontal navigation guidance information during approach and landing. FAA’s decision in 

2016 will be on whether to begin to draw down its category I ground-based instrument 

landing systems. According to FAA, existing category II and III instrument-landing system 

precision approaches will be retained for the foreseeable future. 

FAA Organizational 

Structure 
 

Page 7 GAO-13-693 National Airspace System

Figure 2: Current Federal Aviation Administration (FAA) Organizational Structure with Next Generation Air Transportation 

(NextGen) Responsibilities

Note: Other offices reporting to the FAA Administrator and Deputy Administrator include the Director 

for Audit and Evaluation, Assistant Administrator for Human Resource Management, Assistant 

Administrator for Civil Rights, Assistant Administrator for Communications, Assistant Administrator for 

Government and Industry Affairs, Assistant Administrator for Security and Hazardous Material Safety, 

Assistant Administrator for Commercial Space Transportation, and the Office of Chief Counsel. 

Annually, funds are made available to FAA for the following four 

accounts.

• The operations account funds, among other things, the operation 

and maintenance of the air traffic control system, including employee 

compensation and benefits and safety inspections. FAA received $9.6 

billion for the operations account, which was 60 percent of FAA’s total 

fiscal year 2012 funding. 

FAA Budget and Funding
 

Page 8 GAO-13-693 National Airspace System

• The facilities and equipment account funds technological 

improvements to the air traffic control system, including NextGen and 

existing systems and facilities. The funding in this account is tied to 

the annually updated Capital Investment Plan (CIP), which identifies 

planned capital investment in the national airspace system for the 

next 5 years consistent with the amount requested in the agency’s 

annual budget submission. FAA’s facilities and equipment account 

received $2.7 billion, or 17 percent of FAA’s fiscal year 2012 funding. 

• The research, engineering, and development account funds 

research on issues related to aviation safety, mobility, and NextGen 

systems. This account received $167 million, or 1 percent of FAA’s 

fiscal year 2012 funding. 

• The Airport Improvement Program (AIP) account provides grants 

for airport planning and development. For fiscal year 2012, AIP 

received $3.5 billion, or 22 percent of FAA’s funding. 

The Airport and Airway Trust Fund, which receives revenues from a 

series of excise taxes paid by users of the national airspace system, 

provides nearly all of the funding for FAA’s capital investments in the 

airport and airway system. The trust fund also provides a substantial 

portion—between 43 and 84 percent over the last 10 years—of funding 

for operations with the remaining amount appropriated from general 

revenues.4

 

4

As the Congressional Research Service (CRS) has reported, there has been general 

acceptance that there is a public interest component to the operation of the national 

airspace system, which is appropriated from the U.S. Treasury’s general revenues. This 

compensates for what the military, government, and nonuser beneficiaries (also known as 

societal users) might have contributed if they had actually paid into the trust fund. See 

GAO, Whether the Airport and Airway Trust Fund was created solely to finance aviation 

infrastructure, B-281779 (Feb. 12, 1999) and CRS, Aviation Finance: Federal Aviation 

Administration (FAA) Reauthorization and Related Issues (Washington, D.C.: Apr. 21, 

2008). 
 

Page 9 GAO-13-693 National Airspace System

Based on our prior work, we have identified five areas and related 

challenges facing FAA’s long-term transition to NextGen: (1) sustained 

leadership; (2) managing NextGen interdependencies; (3) equipping 

aircraft with NextGen technologies; (4) preparing FAA’s workforce; and 

(5) consolidating and realigning FAA’s facilities. FAA has made progress 

in addressing these challenges, including filling NextGen leadership 

positions and developing tools to manage NextGen interdependencies. 

The agency is also working to address other identified challenges, 

including incentivizing aircraft operators to equip with NextGen 

technologies, identifying workforce roles under NextGen, and planning for 

facility consolidation and realignment, but has yet to make some 

decisions needed to move forward with these efforts.

As we have previously reported, FAA has struggled to have the 

leadership in place to manage and oversee NextGen implementation, but 

more recently, has begun to fill these positions.5 Since 2003, FAA has on 

several occasions adjusted the reporting lines for both its NextGen 

leadership positions and the JPDO Director. According to FAA, it has 

made various changes in response to industry and congressional 

concerns about fragmented authority over NextGen as well as a 2011

internal assessment of its organization structure. The FAA Modernization 

and Reform Act of 2012 elevates the JPDO Director—redesignating the 

JPDO Director as an Associate Administrator reporting directly to the FAA 

Administrator—a change that has not yet been fully implemented.

6 In 

June 2013, a new Deputy Administrator was appointed and designated 

Chief NextGen Officer, in response to a provision in the FAA 

Modernization and Reform Act.7

While making organizational changes to improve coordination, 

accountability, and oversight of NextGen implementation are positive 

steps, leadership is a critical element of success for large-scale 

Also, according to FAA officials, the 

agency is in the process of searching for qualified candidates for the 

Assistant Administrator for NextGen position, which has been vacant 

since January 2013.

 

5

GAO-13-264. 

6

Pub. L. No. 112–95, § 208(a), 126 Stat. 11, 40.

7

Pub. L. No. 112–95, § 204, 126 Stat., 37. 

FAA Has Made 

Progress in 

Addressing Key 

Transition Challenges, 

but Significant Issues 

Remain to Be 

Addressed to Realize 

NextGen Benefits

More Recently, FAA 

Has Filled Key 

Leadership Positions
 

Page 10 GAO-13-693 National Airspace System

collaborative and system integration efforts like NextGen. As our work on 

interagency collaboration has shown, designating one leader—such as 

the Deputy Administrator’s responsibility over NextGen—can be 

beneficial because it centralizes accountability and can speed decisionmaking. However, complex transformations, such as NextGen, require 

substantial leadership commitment over a sustained period, and 

transitions and inconsistent leadership can weaken the effectiveness of 

the internal and external collaboration required to successfully implement 

NextGen.8 Now that FAA has a new Deputy Administrator that is also 

serving as the Chief NextGen Officer, it will likely be in a better position to 

resolve these leadership challenges.

We have previously reported that interdependencies among FAA’s air 

traffic control acquisition programs have become more prominent as the 

NextGen program shifts from planning to implementation, so that cost 

increases and schedule delays in one program could have a cascading 

effect on other programs.9 While FAA’s acquisition management system 

was not designed for managing NextGen programs in an integrated way, 

FAA has developed processes for overseeing NextGen’s program 

implementation. For example, beginning in February 2012, the Program 

Management Office established a biweekly program review process 

involving FAA Finance, Contracts, NextGen, and ATO staff to discuss and 

address program status, risks, and mitigation strategies.10

 

8

GAO, Managing for Results: Key Considerations for Implementing Interagency 

Collaborative Mechanisms, 

In addition, the 

GAO-12-1022 (Washington, D.C.: Sept. 27, 2012). 

9

GAO-12-223. 

10The Program Management Office within ATO combined acquisition programs into one 

organization. This change was part of a broader effort to reorganize FAA’s NextGen 

efforts around its “Ideas to In-Service Management” (I2I) process. Also part of the I2I 

process, the ATO was divided into two branches: operations and NextGen program 

management. The operations branch focuses on the day-to-day management of the 

national airspace system, while the program management branch is responsible for 

developing and implementing NextGen programs while working with operations to ensure 

proper integration. According to FAA, this process was established to better manage the 

overall process of moving from concept and requirements to investment and 

implementation and to improve the interface between the NextGen organization and the 

program offices implementing NextGen technologies within ATO.

FAA Has Established 

Processes for Overseeing 

NextGen Implementation 

to Help Address 

Challenges in 

Managing NextGen 

Interdependencies 
 

Page 11 GAO-13-693 National Airspace System

Program Management Office reports to the NextGen Management Board, 

which includes the heads of ATO and the key agency lines of business.11

In part, in response to our 2012 recommendation to develop an integrated 

master schedule for each major acquisition, FAA continues to develop its 

NextGen integrated master schedule—a key tool for overseeing 

implementation of the entire NextGen initiative. This tool, when fully 

populated, should capture and track the progress of key NextGen

activities and milestones and provide portfolio-level monitoring of the 

overall NextGen effort, including how changes in one program’s 

milestones may affect other programs and the timelines for NextGen 

implementation as a whole.12 FAA has included implementation activities 

in its integrated master schedule that support the delivery of operational 

capabilities through 2015.13 The agency is still further defining preimplementation activities and their related schedules for 2015 through 

2020, which will be required before it can use this tool to track program 

interdependencies and identify potential risks. According to FAA officials, 

the agency expects this work to be completed by December 2013. See 

appendix II for the status of NextGen acquisitions, as of June 2013, many 

of which are in the early stages of deployment.

 

11The NextGen Management Board is chaired by the FAA Deputy Administrator and 

currently consists of ATO’s Chief Operating Officer as well as the Deputy Chief Operating 

Officer, the Deputy Associate Administrator for Aviation Safety, the Associate 

Administrator for Airports, the Assistant Administrator for Finance and Management, the 

Assistant Associate Administrator for Policy, International Affairs and Environment, the 

Deputy Associate Administrator of Commercial Space Transportation, the Acting Assistant 

Administrator of the NextGen Organization, the Director of JPDO, and the Acquisition 

Executive Other key stakeholder groups, including representatives from FAA’s labor 

unions and the Department of Defense, are invited to send representatives to the 

meetings. 

12FAA has organized NextGen into various portfolios of capabilities, each focusing on a 

series of related operational improvements that together will bring about midterm 

improvements. In March 2013, the Department of Transportation Office of Inspector 

General identified its recommendation to FAA to develop an integrated master schedule 

for implementing the six programs that will provide NextGen’s foundational technologies 

and infrastructure as one of the top 10 highest priority open recommendations for DOT to 

implement.

13FAA previously indicated that implementation activities along with program 

interdependencies through 2018 would be included in the integrated master schedule by 

December 2012.
 

Page 12 GAO-13-693 National Airspace System

FAA continues to assess operational and financial options for 

incentivizing aircraft equipage, as recommended by an industry advisory 

group in 2009, but has yet to make final decisions on how to move 

forward with these efforts.14 While some operational improvements can 

be made with existing aircraft equipment, a number of NextGen 

capabilities that may offer more significant NextGen benefits require a 

critical mass of properly equipped aircraft.15 FAA estimates that the 

NextGen avionics needed on aircraft to realize significant NextGen 

benefits will cost private operators about $19 billion from 2011 through 

2030.16 We have previously reported that reaching a critical mass of 

equipped aircraft is a significant challenge because the first aircraft 

operators to equip will not obtain a full return on their investment until 

many other operators also adopt NextGen technologies.17 In addition, we 

and others have reported that aircraft operators are hesitant to make 

these investments if they do not have confidence that benefits will be 

realized from their investments.18

 

14In 2009, the NextGen Mid-Term Implementation Task Force—which was established to 

prioritize NextGen operational improvements that can be implemented and deliver benefits 

in the midterm (2013—2018) and to build support for long-term NextGen 

implementation—recommended that FAA incentivize equipage through financial 

incentives; streamlining operational procedure delivery; and incorporating a bestequipped, best-served strategy.

For example, while FAA is on track to 

install the ground infrastructure supporting the NextGen surveillance 

system—Automatic Dependent Surveillance-Broadcast (ADS-B)—by 

September 2014, FAA will not be able to realize important benefits from 

ADS-B capabilities until aircraft operators have purchased and installed 

15GAO, Next Generation Air Transportation System: Challenges with Partner Agencies 

and FAA Coordination Continue, and Efforts to Integrate Near-, Mid-, and Long-term 

Activities Are Ongoing, GAO-10-649T (Washington, D.C.: Apr 21, 2010) and 

Transportation: Integration of Current Implementation Efforts with Long-term Planning for 

the Next Generation Air Transportation System, GAO-11-132R, (Washington, D.C.: Nov 

22, 2010).

16FAA, The Business Case for the Next Generation Air Transportation System, August 

2012. 

17An aircraft operator’s return on investment can also depend on operator type and use 

and availability of the technologies.

18GAO, Next Generation Air Transportation System: FAA Has Made Some Progress in 

Midterm Implementation, but Ongoing Challenges Limit Expected Benefits, GAO-13-264

(Washington, D.C.: Apr. 8, 2013).

Creating Incentives 

for Aircraft Operators 

to Purchase NextGen 

Avionics Remains 

a Challenge
 

Page 13 GAO-13-693 National Airspace System

ADS-B Out in their aircraft.19 While FAA has mandated that aircraft equip 

with ADS-B Out20 by January 1, 2020, aircraft operators may delay 

purchase and installation of ADS-B equipment until the deadline because 

of uncertainty about both equipage costs and benefits.21

The FAA Modernization and Reform Act requires FAA to report on 

options to encourage equipping aircraft with NextGen technologies, 

including a policy that gives priority to aircraft equipped with ADS-B 

technology, and the costs and benefits of each option.

According to 

FAA, the agency is addressing this concern by entering into cooperative 

agreements with airlines, aviation institutions, and avionics manufacturers 

to help validate the business case for early adoption of ADS-B. FAA 

officials stated that through its agreements with airlines, the agency would 

collect ADS-B data that will help FAA measure operational benefits, 

reduce uncertainty, and determine timeframes for aircraft operators to 

obtain a return on their investment.

22 In July 2013, 

FAA officials noted that this report—which was due in June 2012—is 

being reviewed and a timeline for its release has not yet been 

established. It is unclear whether this report will address the practical 

implications of establishing benefits for operators that do equip, such as 

granting those operators the use of preferred airspace, routings, or 

runway access. We have reported that designing operational incentives 

and analyzing how they can work in practice would present significant 

challenges.23

 

19ADS-B is a technology that will enable aircraft to continually broadcast flight data, such 

as position, velocity, and altitude, among other types of information, to air traffic controllers 

and other aircraft. As of February 2013, FAA had installed more than 500 of the 790 ADSB ground stations—a key technology in moving toward improved surveillance—with the 

remaining ground stations to be installed by September 2014. 

For example, mechanisms would have to be created so that 

controllers know which aircraft are best equipped—and thus should 

receive the operational benefits—without adversely affecting controller 

20The ADS-B system consists of ADS-B Out—the ability to transmit ADS-B signals, and 

ADS-B In—the ability to receive ADS-B signals from ground and other aircraft, process 

those signals, and display traffic and weather information to flight crews. FAA mandated 

that airplanes be equipped with ADS-B Out by January 1, 2020. As is the case for most 

NextGen equipment, aircraft operators are not required to install ADS-B In but may 

choose to do so.

21GAO-10-188T and RTCA.

22Pub. L. No. 112–95, §§ 211(c), 222, 126 Stat., 46, 54.

23GAO-10-188T. 
 

Page 14 GAO-13-693 National Airspace System

workload or safety. In addition, we recommended in April 2013 that FAA 

include better information in its NextGen planning documents, such as 

forecast benefits for NextGen operational improvements by either location 

or usage, as well as anticipated implementation dates, to help aircraft 

operators better understand when and where they can expect to realize 

benefits, which would include those resulting from operational incentives. 

FAA concurred with the recommendation and is working to integrate its 

NextGen plans to provide additional details and connectivity and map 

interdependencies between planned operational improvements. It expects 

to complete this work by September 2014. In addition, according to FAA, 

the agency has been collaborating with aircraft operators and avionics 

developers to develop stakeholder knowledge and confidence in NextGen 

and encourage equipage.

In May 2012, FAA began the process of determining how to design and 

implement a public-private equipage-financing program.24 In developing 

the program, FAA officials said that they reached out to other federal 

agencies—such as the Departments of Agriculture, Education, Energy, 

and the modal administrations of Transportation—to understand various 

options for establishing a loan-guarantee program. FAA proposed a 

minimum bundle of equipment and a bundle of optional equipment that 

could be financed under such a program, and then conducted outreach 

through public meetings, market surveys, and individual meetings with 

aviation representatives to get industry perspectives on the overall 

program structure and the proposed equipage bundles. FAA officials 

noted that they are continuing to develop the program and do not expect 

to be in a position to issue loan guarantees until at least 2014.

FAA has worked to address longstanding challenges associated with 

involving its air-traffic controller (controllers) and technician workforce in 

developing and implementing NextGen systems, which is critical to the 

successful implementation of NextGen. As we have previously reported, 

the lack of stakeholder involvement—particularly, controllers—in air traffic 

 

24The FAA Modernization and Reform Act authorized the creation of a program to 

facilitate public-private financing, such as loan guarantees and other credit assistance 

tools, for equipping general aviation and commercial aircraft with NextGen technologies.

Pub. L. No. 112–95, § 221, 126 Stat., 54. Such programs must also meet the 

requirements established by the Federal Credit Reform Act of 1990, Pub. L. No. 101-508,

§ 13,201, 204 Stat. 1388-609 , amending title V of the Congressional Budget Act of 1974 

and codified at 2 U.S.C. §§ 661-681.

FAA Has Addressed Some 

Workforce Challenges, 

and Efforts Are Under Way 

to Address Others
 

Page 15 GAO-13-693 National Airspace System

control modernization efforts contributed both to the delayed 

implementation of new technologies and optimized flight routes and to 

cost increases.25

FAA efforts to align its workforce planning with controller, technician, and 

acquisition workforce needs under NextGen, however, remain a work in 

progress. During the NextGen transition, FAA will need a sufficient 

number of skilled controllers who are able to increasingly rely on 

automation and technicians who are able to properly maintain and certify 

both existing and NextGen systems. FAA will also require a sufficient 

acquisitions workforce, which is key to successfully acquiring NextGen 

systems and equipment. In 2011, we reported that FAA had just begun to 

consider how NextGen technology might affect its technician workforce 

and in 2013, found that FAA faced various challenges with its acquisition 

workforce. As described below, the FAA Modernization and Reform Act 

requirements related to assessing and improving FAA’s workforce 

planning, in conjunction with the workforce planning efforts FAA has 

under way, may provide a more strategic focus to FAA’s management of 

its workforce during the transition to NextGen.

Both the controller and technician labor agreements now 

include provisions that require representatives from both labor groups to 

be involved in developing and testing NextGen technologies. The 

involvement of FAA’s workforce in the development of these systems will 

be critical in identifying and remedying operational challenges that may 

arise and obtaining workforce support for transitioning to the new 

technologies.

• Controller workforce: FAA’s 10-year controller workforce plan aligns 

the controller’s staffing levels with anticipated traffic. However, these 

staffing projections do not take into account NextGen improvements, 

which FAA expects to lead to increased workforce productivity. FAA’s 

plan explains that these improvements are not considered because 

the increased productivity from NextGen capabilities and its impact on 

workforce size and composition will evolve over time and, at this time, 

cannot be accurately projected. As required by the FAA Modernization 

and Reform Act, the National Academy of Science is conducting a 

study of the standards used to estimate FAA’s controller staffing 

 

25GAO, Air Traffic Control: FAA Reports Progress in System Acquisitions, but Changes in 

Performance Measurement Could Improve Usefulness of Information, GAO-08-42

(Washington, D.C.: Dec. 18, 2007) and GAO-13-264. 
 

Page 16 GAO-13-693 National Airspace System

needs,26

• Technician workforce: We recommended in 2010 that FAA develop a 

comprehensive, written strategy for its technician workforce that fully 

incorporates key leading practices in strategic workforce planning, 

such as determining the critical skills and competencies that will be 

needed to achieve current and future results.

which it expects to complete in mid-2014. According to FAA 

officials, they will then assess and determine how to incorporate the 

findings of this study into their controller staffing models.

27 FAA officials anticipate 

completing a technician-staffing model by December 2013. In June 

2013, a National Academies of Science committee tasked with

examining the model, however, cast doubts on FAA’s ability to meet 

that timeframe given the complexities involved in developing and 

implementing a staffing model. The committee also reported that 

changes in the national airspace system, such as those from NextGen 

and unspecified policies on reducing existing systems and 

infrastructure, make the technicians’ workload ambiguous and 

complicate FAA’s task. For example, some NextGen technologies, 

like ADS-B, are being or are planned to be installed, owned, and 

maintained by a contractor while the services or data are or will be 

leased by FAA. While FAA technicians will not service and maintain 

this equipment, they will play a role in certifying the services provided 

by this equipment. A provision in the FAA Modernization and Reform 

Act requires that the administrator ensure that equipment, systems, or 

services meet appropriate certification requirements regardless of 

whether they are publicly or privately owned.

28

 

26Pub. L. No. 112–95, § 608, 126 Stat., 115.

FAA policy had been 

to require technicians to certify only FAA-owned systems, 

subsystems, and services as well as provide oversight of systems 

owned by the military, other agencies, and non-federal entities. FAA 

has yet to determine how this change might affect its current 

maintenance policies and technicians’ responsibilities for ADS-B or 

future equipment that is under a service contract. FAA officials 

indicated that they are developing a policy to provide additional 

oversight for leased services that would include periodic inspections 

and expect the policy to be in place later this year.

27GAO, Federal Aviation Administration: Agency Is Taking Steps to Plan for and Train Its

Technician Workforce, but a More Strategic Approach Is Warranted, GAO-11-91

(Washington, D.C.: Oct 22, 2010).

28Pub. L. No. 112-95, § 215, 126 Stat., 51.
 

Page 17 GAO-13-693 National Airspace System

• Acquisition workforce: As we reported in January 2013, FAA has also 

identified staffing challenges for segments of its acquisition workforce, 

including program/project management and research and 

engineering.29

We previously reported that FAA must adjust its training strategy as 

NextGen capabilities are brought online, and the FAA Modernization and 

Reform Act called for assessments of and improvements in FAA’s 

controller and technician training programs.

Challenges included an anticipated growth in workforce 

requirements, combined with expected retirements (e.g., 39 percent of 

FAA project/program managers are eligible to retire in 2015) and the 

difficulty in hiring experienced, highly qualified candidates. In addition, 

we found that some of FAA’s estimates of acquisition workforce 

requirements may be understated because they were based on, or 

revised to reflect, budget realities, as opposed to the number of staff 

needed to do the work. FAA officials indicated that they are taking 

steps to address these challenges.

30 FAA is restructuring its 

training program to better align job tasks with course material and to 

improve overall course management. According to FAA officials, they 

have begun to develop a strategic training improvement plan for FAA’s 

controllers and expect to complete a job task analysis by August 2013, 

but have not identified a timeline for completing its plan. As part of this 

effort, FAA is assessing the extent to which controllers’ current job tasks 

align with the controller’s training curriculum and determining whether the 

controllers’ responsibilities would change based on NextGen 

technologies, automation, and procedures that are planned through 2018, 

thus necessitating curriculum changes. FAA also expects to complete by 

September 2013 a strategic training improvement plan for technicians, 

which we recommended in 2010.31

 

29GAO, Acquisition Workforce: DOT Lacks Data, Oversight, and Strategic Focus Needed 

to Address Significant Workforce Challenges, 

However, while FAA is able to assess 

the extent to which technicians’ current job tasks align with the technician 

training curriculum, FAA training officials noted that they cannot project 

future training needs because, as noted, the agency has not yet fully 

determined technicians’ responsibilities under NextGen. FAA is also in 

the early stages of centralizing the management of its training curriculum 

GAO-13-117 (Washington, D.C.: Jan. 23, 

2013).

30Pub. L. No. 112-95, §§ 224, 605, 126 Stat., 55, 113. 

31GAO-11-91. 
 

Page 18 GAO-13-693 National Airspace System

to reduce duplication of infrastructure, resources, and personnel resulting 

from its current decentralized processes. FAA is developing a Learning 

Content Management System (LCMS) to serve as a single database to 

help FAA administer, develop, track, report, and deliver training programs 

and to allow for increased collaboration with course development, which 

could help reduce course development time. 

In November 2011, FAA approved an initial plan to consolidate en-route 

centers and terminal radar approach control (TRACON) facilities into 

large, integrated facilities. This initial plan called for consolidation to occur 

over the next two decades (through 2034).32 FAA planned to begin this 

consolidation effort by building a new integrated facility for managing 

airspace in the New York/New Jersey/Philadelphia metropolitan areas. 

This facility—referred to as the New York Integrated Control Facility (New 

York ICF)—would integrate the activities of two major facilities in the 

Northeast—the New York En Route Center and New York TRACON. The 

New York ICF is estimated to cost $235 million to construct, which FAA 

has requested in its fiscal year 2014-budget request.33

In a separate effort, FAA is still working to prepare a national-facilities 

realignment and consolidation report, which was required by the FAA 

Modernization and Reform Act to be completed by June 2012. This report 

is to include the agency’s recommended realignment and consolidation 

actions along with justifications, projected costs and savings, and 

proposed timing for implementation of each recommendation.

However, FAA has 

yet to approve construction for this new facility—a decision originally 

scheduled for November 2012. FAA officials have stated that, in light of 

the current budget constraints, the agency is considering adjusting its 

current plans, further limiting project scope, and exploring different 

financing options, such as partnerships with local and other government 

agencies.

34

 

32This long-term plan divided the national airspace system into six segments across the 

nation and realigned and consolidated facilities based on operations, airspace 

responsibility, and geographic location.

In 

33The President’s fiscal year 2014 budget request calls for an immediate $50 billion 

transportation initiative to finance upfront infrastructure costs, including the New York ICF. 

This funding request is in addition to DOT’s current budget authority. 

34Pub.L.112-95, §804, 126 Stat., 119. 

FAA Cannot Proceed 

with Realigning and 

Consolidating Facilities 

Until Key Decisions 

Are Made
 

Page 19 GAO-13-693 National Airspace System

September 2012, FAA chartered a collaborative working group with FAA 

management and the controller and technicians unions to recommend 

criteria for evaluating realignment and consolidation scenarios of FAA 

TRACON services and facilities based on an assessment of existing 

models and criteria. According to FAA officials, this collaborative 

approach had not previously existed. In July 2013, FAA officials noted 

that they had developed a process for identifying potential facilities for 

consolidation and realignment and were evaluating realignment options 

as required by the FAA Modernization and Reform Act, but had not yet 

identified which facilities would be consolidated or realigned or a time 

frame for developing such a list.35

FAA’s efforts to establish assessment criteria could help it address prior 

challenges in presenting sound business cases for previous consolidation 

efforts.36 For example, in a few instances in the past 3 years (e.g., 

attempts to consolidate Boise, Idaho, and Salt Lake City, Utah terminal 

facilities, as well as consolidation efforts in Texas), flawed estimates of 

cost savings and operational efficiencies slowed or halted FAA’s 

consolidation efforts. Our work has shown that consolidation initiatives 

that are based on a clearly presented business-case or cost-benefit 

analysis, grounded in accurate and reliable data, can provide a datadriven rationale for why an agency is undertaking a particular initiative 

and show stakeholders that a range of alternatives has been 

considered.37

We have previously reported that once FAA develops a facility 

consolidation plan, it can identify which existing facilities to repair and 

maintain and, in doing so, potentially reduce overall facility repair and 

 

35Additionally, FAA’s contract with the air traffic controllers’ union requires that FAA notify 

the union as soon as possible but not less than one year in advance of the closure of a 

facility, facility consolidation, or inter-facility reorganization requiring reassignment of 

employees. This provision, along with the status of FAA’s realignment and consolidation 

efforts, suggests that it will be no less than 2 years before realignments and 

consolidations occur. 

36A business-case analysis, a comparative analysis that presents facts and supporting 

details among competing alternatives, can help agencies ensure they are using public 

funds most effectively and preparing to meet future performance goals.

37GAO, Streamlining Government: Questions to Consider When Evaluating Proposals to 

Consolidate Physical Infrastructure and Management Functions, GAO-12-542

(Washington, D.C.: May 23, 2012.)
 

Page 20 GAO-13-693 National Airspace System

maintenance costs. Fully realizing the benefits of NextGen’s capabilities 

requires reconfiguring facilities that handle air traffic control, but 

maintaining existing facilities will also be critical during the projected 20-

year transition (2014–2034). While FAA’s efforts to sustain and realign 

existing facilities and develop future facilities plans are under one FAA 

office, these efforts are not yet coordinated so that FAA can identify which 

existing facilities to continue to repair and maintain and for how long. FAA 

facilities officials emphasized that FAA’s broader consolidation efforts are 

still undefined and that its plans for realignment have not yet been 

approved by external stakeholders. Officials expect that once its 

realignment plans are finalized, they will coordinate schedules and align 

timelines for facilities maintenance, replacement, and realignment 

evaluations. Making timely decisions on how best to realign and 

consolidate facilities—in addition to aligning those efforts with its current 

facilities maintenance plans—could help FAA avoid unnecessarily 

investing in facilities that may not be needed for NextGen.

FAA data show high operational availability of its air-traffic control 

systems. Specifically, FAA’s Performance and Accountability Reports in 

fiscal years 2004 through 2011 reported on how unscheduled, or 

unanticipated, outages affect the availability of air traffic control systems 

at the airports with the most air traffic control activity.38 Since FAA started 

publicly reporting this measure in 2004, it has reported exceeding its goal 

of 99 percent operational availability for all years, except the first year—

which was the only year that the measure’s calculation included both 

scheduled and unscheduled outages (fig. 3).39

 

38FAA calculates adjusted operational availability as a ratio of maximum facility/service 

hours minus all unscheduled outage time over maximum facility/service hours, expressed 

as a percentage. According to the FAA NAPRS Order JO 6060.15E, an outage is based 

on a full interruption of 1 minute or more.

FAA officials said that the 

agency changed the measure in fiscal year 2005 to eliminate outages due 

to airport or runway construction and equipment modifications and focus 

on FAA’s ability to respond to unscheduled, or unplanned, outages. While 

some of the airports included in this measure have changed over time, 

39In 2004, according to the FAA, it did not achieve 99 percent operational availability 

because of a 0.38 percent increase in scheduled downtime from improvement projects. In 

2005, the formula was redefined to exclude scheduled outages. FAA then recalculated its 

fiscal year 2004 and found that it had exceeded 99 percent under this new measure 

definition.

Existing System 

Performance Remains 

High, but the 

Reported Measure 

Is Insufficient to 

Determine Overall 

System Condition
 

Page 21 GAO-13-693 National Airspace System

the 30 airports that have been consistently included in the measure since 

2004 enplane 63 percent of the country’s passengers and account for 68 

percent of air traffic operations, but include only 6 percent of the total 

national airspace systems.40

 

40In 2004, this measure tracked the operational availability—i.e., the effect of scheduled 

and unscheduled outages on overall availability—for the 35 Operational Evolution 

Partnership (OEP) airports—defined as the U.S. airports with the most significant 

commercial activity. In 2005, FAA then began tracking “adjusted operational availability” 

for these same airports; adjusted operational availability excludes scheduled outages from 

the calculation. In 2011, FAA changed the metric again to report adjusted operational 

availability for the recently defined “Core 30” airports. FAA replaced the OEP airports with 

the “Core 30” airports because they represent the top 30 airports in terms of passenger 

activity.

According to FAA officials, the agency 

focuses on maintaining a high level of operational availability for the 

systems at these airports since loss of radar or communications 

equipment at these airports can affect overall system capacity and result 

in delays at airports across the national airspace system. According to 

FAA, such delays can cost millions of dollars per occurrence. FAA data 

also show that operational availability for all systems—including the 

remaining 94 percent of FAA systems not included in the publicly reported 

measure—also remains above 99 percent. FAA maintains redundancies 

in the system to keep operational availability high. For example, a radar 

may continue to provide service if one channel has failed because a 

redundant channel is capable of providing service.
 

Page 22 GAO-13-693 National Airspace System

Figure 3: Annual Reported Performance Measure for Air Traffic Control System 

Operational Availability for 30 Airports with the Most Activity, Actual and Target, 

Fiscal Years 2004–2011

Notes: 2004 is the only year that the measure’s calculation included both scheduled and unscheduled 

outages. In 2004, according to the FAA, it did not achieve 99 percent operational availability because 

of a 0.38 percent increase in scheduled downtime from improvement projects. In 2005, the formula 

was redefined to exclude scheduled outages. FAA then recalculated its fiscal year 2004 and found 

that it had exceeded 99 percent under this new measure definition. According to the Fiscal Year 2012 

Performance and Accountability Report, FAA discontinued its reporting of this measure after fiscal 

year 2011. 

a

As previously noted, FAA’s 2004 measure included both scheduled and unscheduled outages. 

According to the FAA, it did not achieve 99 percent operational availability because of a 0.38 percent 

increase in scheduled downtime from improvement projects. 

b

The measure was revised in 2011 to include the “Core 30 airports,” which represent the top 30 

airport as measured by passenger activity.

However, the reported high operational availability levels do not fully 

illustrate the underlying performance and condition of FAA’s air traffic 

control systems, some of which have experienced increasing outages. To 

obtain a fuller picture of overall system performance and maintenance 

requirements, we analyzed trends in the underlying number and duration 

of unscheduled and scheduled outages for almost 36,000 systems in the 
 

Page 23 GAO-13-693 National Airspace System

national airspace system from fiscal years 2001 through 2012. As figure 4 

shows, while the number of systems has increased by approximately 19 

percent from fiscal year 2001 to fiscal year 2012, the total scheduled and 

unscheduled outages greatly outpaced the increase in systems during 

this time period. From fiscal year 2001 to fiscal year 2012, scheduled 

outages doubled while unscheduled outages increased 45 percent. In 

addition, the total duration of unscheduled outages increased 132 percent 

from fiscal year 2001 to fiscal year 2012 while total duration of scheduled 

outages increased 172 percent from fiscal year 2001 to fiscal year 2012.

Figure 4: Number of Systems and System Outages throughout the National Airspace System, Fiscal Years 2001–2012

FAA cited a number of factors contributing to these generally increasing 

trends in scheduled and unscheduled outages, as well as to increases in 

scheduled and unscheduled outage time, including:

• the age of the existing systems;

• the agency’s 2006 changes to its maintenance policy, including 

moving to more centralized reporting of outages; and
 

Page 24 GAO-13-693 National Airspace System

• the agency’s 2007 effort to tighten its reporting procedures for 

unscheduled outages.

In addition, the increased outage time may indicate, in part, that 

maintenance and troubleshooting activities are requiring more effort and 

longer periods of time. FAA officials expect the number and duration of 

outages to increase in fiscal year 2013 because of required budget 

reductions.41

Furthermore, according to FAA, many of the existing systems that have to 

be maintained for many years face growing agency concerns about parts 

availability and technology obsolescence, as well as the need for 

continued upgrades to extend their service life through the transition. For 

example, one of FAA’s navigation systems—the Distance Measuring 

Equipment (DME) system—has obsolete parts that require reengineering 

and remanufacturing of existing parts for system repairs.42 According to 

FAA, while individual repairs of DMEs are infrequent, these repairs are 

becoming more expensive because of the effort required to develop parts 

for repairs. FAA also determined that further extending the service life of 

DMEs would require “cannibalization” of old DME equipment that has 

been decommissioned.43

 

41According to FAA officials, when fiscal resources became constrained in fiscal year 

2013, FAA began focusing on maintaining equipment at airports with the most significant 

air traffic control activity and impact on overall operations in the national airspace system 

and applying a “run-to-fault” maintenance approach for supporting systems at the 

remaining airports. These officials noted that FAA was able to adjust its approach once 

The Reducing Flight Delays Act of 2013 was enacted granting the agency flexibility to 

transfer funds. Pub. L. No. 113-9, § 2, 127 Stat. 443, 444 (2013). 

In another example, under current FAA plans, 

one of FAA’s primary radar systems, which was originally installed in 130 

locations between 1989 and 1994, is expected to remain in service 

through 2025. Following service life extension of this system in 2008 and 

2010, FAA is making further modifications to these radar systems to 

upgrade the current hardware, which is beyond its current service life and 

integral to continuous operation of the national airspace system.

42DME provides the pilot with direct positioning information between the aircraft and the 

DME. 

43Cannibalization means that pieces of a discarded part are reclaimed and re-assembled 

to create a functional part and is typically used a last-resort support option.
 

Page 25 GAO-13-693 National Airspace System

Additionally, FAA internally tracks the maintenance needs of the facilities 

and infrastructure that support these systems, which suggest potentially 

increasing deferred maintenance.

Staffed facilities: According to FAA estimates for fiscal year 2012, the 

deferred maintenance backlogs for the 23 en-route facilities and 134 

terminal facilities that had been inspected were $98 million and $82 

million, respectively.44 These estimates do not include the 409 terminal 

facilities, which have not been inspected.45

Unstaffed infrastructure and facilities: According to FAA assessments, 

half of the agency’s over 28,000 unstaffed infrastructure and facilities—

which include shelters, roofs, towers, heating ventilation and cooling 

systems, interior electrical distribution, and security fences—is at or 

beyond the end of its service life and requires modernization or 

replacement that, if not addressed, could affect this infrastructure’s 

support of ensuring reliable operations in the national airspace system. 

For example, FAA found in 2008 that many towers and platforms 

associated with its surveillance facilities, as well as many of its 

communication towers, do not meet federal occupational health and 

safety protection standards, making it difficult for FAA technicians to 

safely maintain the related systems.

We have a separate ongoing 

job that is assessing FAA staffed facility condition and the statistical 

method used to estimate the condition of its uninspected terminal facilities 

and plan to report our final results later this year. 

FAA’s data on deferred maintenance levels also suggest deteriorating 

conditions of the unstaffed infrastructure, but given the limited universe of 

data, this estimate may not be an accurate reflection of the true level of 

 

44For its en-route and terminal facilities, FAA defines deferred maintenance as the cost of 

rebuilding or replacing components whose service life has exceeded their scheduled 

lifetime as of the forecast year. FAA does not include preventative maintenance and minor 

repairs in its deferred maintenance calculations.

45FAA uses a technical consultant to annually inspect a portion of its en-route and terminal 

facilities. The consultant inspects each en route facility approximately once every 4 to 5 

years, and “roll-up” reports for these facilities contain actual inspection results for each of 

the 23 facilities. For terminal facilities, “roll-up” reports contain actual inspection results 

from facilities inspected over the most recent 6-year period. FAA’s most recent terminal 

facility “roll-up” report, for example, contains information from 134 facilities inspected—

which reflect less than one quarter of all terminal facilities—from January 2007 through 

December 2012.
 

Page 26 GAO-13-693 National Airspace System

deferred maintenance, which we discuss later in this report. Table 2 

shows almost $3 billion in total deferred maintenance for some of FAA’s 

unstaffed infrastructure and system, based on the most recently available 

FAA capital-funding estimates. FAA used its 2008 survey of about 34 

percent of its unstaffed infrastructure and facilities to estimate that 

deferred maintenance of its entire unstaffed infrastructure would double 

from about $212 million in 2008 to about $446 million in 2012.46 At current 

funding projections, FAA estimates that the total deferred maintenance for 

this infrastructure will grow by an average annual rate of roughly $27 

million and reach approximately $715 million by 2022. While FAA states 

that it is striving to reduce the backlog of deferred maintenance, a 

substantial deferred maintenance backlog can increase the risk for 

operational failures and premature equipment replacement. For example, 

a leaking landing system shelter roof could affect either the electronics 

housed inside, thus creating an outage, or the heating and cooling

systems, which are vital to ensuring the continued performance of the 

housed hardware and software.

 

46Between 2006 and 2008, FAA conducted condition assessments on roughly 34 percent 

of its unstaffed infrastructure and facilities to collect information on their condition. FAA 

used the results of this non-random sampling of facilities to extrapolate an estimate for the 

remaining unstaffed infrastructure and facilities. 
 

Page 27 GAO-13-693 National Airspace System

Table 2: The Federal Aviation Administration’s (FAA) Capital Plan and Deferred Maintenance Levels for Selected Unstaffed Air 

Traffic Control Infrastructure and Systems 

Other air control facilities

2013-2017 Capital Plan 

(in millions)

Deferred maintenance 

(in millions)

Difference

(in millions)

Long-range radar $15.0 $114.0 $99.0

Fuel storage tank replacement and monitoring 58.4 181.8 123.4

Unstaffed infrastructure sustainment 151.2 444.6 293.4

Airport cable loop systems support 78.7 2,000.0 1,921.3

Electrical power systems sustainment 468.0 992.0 524.0

Total $771.3 $3,732.4 $2,961.1

Source: FAA.

Note: According to FAA, this list reflects the unstaffed infrastructure and systems with the largest 

estimated deferred maintenance levels in 2012.

While FAA has various internal metrics showing the deteriorating 

condition of the current systems, it no longer reports on a measure that 

communicates the condition of its existing systems. According to FAA, its 

goals, such as those in the annual Portfolio of Goals and the Performance 

and Accountability Report, are intended to assist managers and policy 

makers and inform the public on what the agency has accomplished with 

its available resources. However, FAA’s 2012 Performance and 

Accountability Report did not include the operational availability measure, 

though FAA still tracks this internally for trending and performance 

management purposes. When we asked FAA Technical Operations 

officials why the adjusted operational availability measure was removed, 

they told us that the measure was prematurely removed from the report 

and that efforts are under way to identify a better measure of FAA’s 

national airspace services. FAA officials did not provide details on the 

factors being considered in establishing a new publicly reported measure 

or a time frame for this effort. We reported in April 2013 that FAA is 

currently conducting an agency-wide effort to review and harmonize its 

performance metrics to bring order, consistency, and accuracy to metrics 

reporting across its business lines and that it has made progress in 

developing various performance metrics, including those that respond to 

the FAA Modernization and Reform Act requirements and to 

recommendations we made in 2010.47

 

47

We also emphasized the 

GAO-13-264. 
 

Page 28 GAO-13-693 National Airspace System

importance of continued progress in this area. Additional information on 

current system condition could help FAA stakeholders, such as Congress, 

assess and make decisions about how to fund and monitor FAA’s efforts, 

particularly in light of current budget constraints and continued 

investments in NextGen, as we discuss later in this report.

Recognizing that its cost estimates for sustaining current systems, 

facilities, and infrastructure and implementing NextGen exceed 

anticipated funding levels, FAA is developing a plan to address 

maintenance and sustainment issues for both existing FAA systems and 

facilities. According to FAA officials, the plan will help decision makers 

understand the funding levels needed to address the maintenance and 

sustainment issues of the current systems and facilities. In November 

2012, FAA began developing this plan to address facilities sustainment 

issues. To help prepare this plan and the fiscal year 2015 budget, FAA is 

developing a standardized process that would prioritize sustainment 

projects for all types of facilities, including towers, en-route centers, 

TRACONs, and unstaffed infrastructure. This approach differs from prior 

years where facility sustainment activities were decentralized, with 

different offices within ATO individually prioritizing their facilities’ 

sustainment projects. According to FAA officials, they plan to use a new 

two-tier process where program officials rank their projects first and then 

those projects are prioritized by operational need, risk, employee safety, 

mission critical needs, and environmental requirements across all 

facilities types. In January 2013, FAA decided to expand its facilities 

maintenance and sustainment plan to also include system sustainment

issues. To support this effort, FAA Technical Operations officials noted 

that they are developing a “get well” plan for national airspace systems 

that will include specific goals, measures, and outcomes. In developing 

this plan, officials noted that they have developed a prioritization process 

for systems maintenance and sustainment to support efforts to “right size” 

the national airspace system, reduce costs, and simplify complexity to 

support the transition to NextGen. FAA expects to complete its planning 

effort by September 30, 2013, in line with its fiscal year 2013 business 

plan. 

In developing the plan, FAA will be considering issues that may prove 

difficult to resolve. In particular, FAA noted that there has been a funding 

imbalance between staffed and unstaffed facilities, with many unstaffed 

facilities facing deteriorating infrastructure issues that put employees at 

risk of injury when they perform maintenance. However, FAA lacks 

sufficient data on the condition of these facilities to identify the size of the 

FAA’s Efforts to 

Develop a Long-term 

Systems and Facilities 

Maintenance Strategy 

Could Be Hampered 

by Limited Data on 

Condition 
 

Page 29 GAO-13-693 National Airspace System

deferred maintenance backlog and the potential resources needed to 

maintain that infrastructure. FAA is using data from its 2008 assessment 

of unstaffed infrastructure—which was a non-random sample that 

covered 34 percent of this infrastructure—to begin developing an asset 

database to help track the age and replacement dates for its unstaffed 

infrastructure inventory. FAA has not determined time frames or methods 

for either collecting condition information on the remaining 66 percent of 

the unstaffed infrastructure or developing estimates that more accurately 

represent the condition of those facilities, but the agency recognized the 

need to accurately survey its unstaffed infrastructure and is currently 

examining the best and most cost effective means to survey these 

facilities.

48 FAA uses a decentralized approach—similar to what had been 

used for facility sustainment prioritization—to identify unstaffed 

infrastructure sustainment projects where field technicians or engineers 

prepare project requests, which are based on type of project and mission 

criticality. However, because FAA’s project priorities are being 

established at the individual program office level and not against 

established criteria from an agency perspective—a leading practice for 

making capital investment decisions—FAA cannot ensure that identifying 

those projects that are most critical to operating the overall national 

airspace system.49

 

48FAA currently relies on service support center managers assigned to a certain 

geographic area to identify and submit unstaffed infrastructure condition issues as part of 

their work in the field. FAA facilities officials noted that one approach to identifying 

unstaffed infrastructure condition would be for technicians to collect the information as part 

of their regularly scheduled system maintenance. However, officials recognize that if they 

were to apply such an approach, they would need to determine whether technicians would 

know what to look for and would have the additional time to assess infrastructure condition 

as part of their duties.

FAA also recognized that without an accurate number 

and facility condition, the agency cannot identify the financial needs, 

priority list, or remediation strategies for these structures. In addition, as 

FAA deploys new NextGen technologies, there may be opportunities to 

consolidate equipment onto fewer pieces of unstaffed infrastructure. 

Without more complete data, however, FAA will be challenged to identify 

consolidation opportunities and realize the potential cost savings that 

might come from consolidating unstaffed facilities and infrastructure. In 

the meantime, the office overseeing unstaffed infrastructure is working to 

coordinate with the NextGen program schedule to avoid having to remove 

and reinstall equipment to upgrade or replace navigation and landing 

49GAO, Federal Buildings Fund: Improved Transparency and Long-term Plan Needed to 

Clarify Capital Funding Priorities, GAO-12-646 (Washington, D.C.: July 12, 2012).
 

Page 30 GAO-13-693 National Airspace System

infrastructure. In addition, FAA recognizes that some reductions in 

NextGen programs or other projects may be necessary to shift funding to 

sustain existing systems and facilities, and FAA will need to merge the 

priorities established in its maintenance plan with the NextGen 

implementation plan in order to understand and make the necessary 

trade-offs given overall resource levels. As we discuss in the next section, 

under current budget estimates, FAA could face reduced budget levels in 

the coming years, making the agency’s efforts in developing this plan 

critical in identifying how it will sustain all systems and control costs over 

the long term in a constrained budget environment.

FAA also plans to discontinue the use of systems facing significant 

sustainment issues or that are no longer needed as NextGen capabilities 

are deployed.50 While FAA discontinues the use of equipment from the 

national airspace system on a regular basis, these efforts have been 

more limited than the full-scale initiatives that are expected to occur 

during the NextGen transition. FAA’s NextGen plans identify dates for 

when the agency will make decisions on discontinuing certain existing 

systems and facilities, such as navigation aids like the 1,500 Instrument 

Landing Systems, as well as surveillance, weather, and communication 

systems. FAA’s first major effort is to discontinue half of the 967 very high 

frequency omnidirectional radio range (VOR) systems (see fig. 5), 

between 2014 through 2020 and establish a minimal operating network of 

VORs.51

 

50A review of FAA Handbook 7031.3 appears to draw no clear distinction between 

discontinuance and decommissioning of a navigational service, but discussion with FAA 

personnel appeared to distinguish between discontinuance of a service as opposed to 

decommissioning of a facility.

According to FAA data, the number of unscheduled outages for 

VORs increased 130 percent between fiscal years 2001 and 2011, and 9 

out of 10 VORs are beyond their useful service life. Because parts for this 

system can no longer be procured, FAA has to reengineer and construct 

new parts from existing VOR parts, which is a time- and resourceintensive process. Current costs for operating and maintaining VORs 

exceed $110 million per year and are increasing, in addition to the costs 

51A VOR is a ground-based system radiating Very High Frequency (VHF) radio signals to 

compatible airborne receivers, providing pilots a direct indication of location relative to the 

facility.
 

Page 31 GAO-13-693 National Airspace System

associated with maintaining the flight procedures needed to operate with 

this technology.52

Figure 5: Very High Frequency Omnidirectional Radio Range (VOR) Station

While FAA anticipates developing an agreed-upon list of VORs to 

discontinue and the dates when they will be discontinued by September 

2014, the agency will first need to overcome challenges in obtaining 

stakeholder buy-in and securing funding. FAA’s efforts to discontinue 

other existing systems will involve these same types of steps and will 

likely face similar difficulties. For example, decisions on discontinuing 

radar sites will involve coordination with the Departments of Defense and 

Homeland Security and other aviation stakeholders to ensure that FAA’s 

surveillance network, among other things, can detect, identify, and track 

aircraft.

 

52The cost for operating the VORs is being validated as FAA develops its business case

for the VOR’s minimum operating-network implementation program.
 

Page 32 GAO-13-693 National Airspace System

• Stakeholder buy-in: FAA has encountered difficulties in obtaining 

agreement on exactly which VORs to retain and whether those 

selected will provide sufficient backup service. As part of its effort to 

develop a minimum operating network of VORs, FAA released a highlevel plan outlining the transition from current navigation aids to 

performance-based navigation services under NextGen. In 

commenting on this plan, several stakeholders—while supportive of 

the transition—raised concerns about the timing of the VOR network 

reduction, questioning whether aircraft operators would have the 

necessary equipment to transition from using VORs to performancebased navigation as a primary means of navigation by 2020. For 

example, the Department of Defense (DOD) raised concerns that only 

about 30 percent of its fleet of 14,600 aircraft have performancebased navigation capabilities and initially estimated that increasing 

that equipage rate to approximately 75 percent would cost 

approximately $3.7 billion.53 DOD noted that FAA’s goal to 

discontinue navigation aids, such as VORs, by 2020 did not provide 

DOD sufficient time to budget, modify, test, and certify fleet aircraft to 

meet the potential new equipment standards.54

 

53DOD noted that due to the interrelationship between en route and terminal approach 

equipage requirements, portions of this cost estimate include performance navigation 

upgrades beyond what might be needed to operate in a reduced VOR network.

According to FAA 

officials, they asked DOD to identify where the department would 

need VOR coverage in the national airspace system and agreed to 

address those requirements, although FAA anticipates that it could 

affect fewer than 50 VORs. In addition, according to FAA’s disposition 

of comments on the proposed strategy, of the 330 comments 

received, a number of those comments expressed concerns about 

whether a reduced VOR network would provide the necessary backup 

service in the event of interference or disruption with satellite-based 

systems. General aviation stakeholders agreed that while the number 

of VORs should be reduced, they want more details on how FAA 

would make this transition—including the specific VORs that would be 

retained or discontinued and whether adequate flight approach 

procedures would continue to be available or impacted by the 

drawdown. FAA is developing a communications plan to guide its 

efforts in soliciting stakeholder input, which could help address these 

54DOD also noted in its comments that as the industry will be making modifications to 

aircraft navigation systems to comply with the ADS‐B Out mandate by 2020, FAA must 

properly synchronize the discontinuance of navigation systems to minimize disruptions of 

aircraft upgrade schedules and prevent multiple aircraft modifications.
 

Page 33 GAO-13-693 National Airspace System

concerns. FAA also has to obtain agreement among the 18 FAA 

offices and two bargaining units affected by the VOR reduction and, to 

do so, has begun vetting a list of potential VORs to discontinue within 

the agency. Later in 2013 or early 2014, FAA anticipates releasing for 

external stakeholder input an agency-vetted list of potential VORs to 

retain.

• Funding: Concurrent with its efforts to identify the VORs to maintain, 

FAA officials with the navigation program are developing a business 

case for obtaining the $6 million in annual funding between fiscal 

years 2014 and 2020 to execute the plan. These officials noted that if 

the agency were not able to secure funding, the current timeframe for 

reducing the VORs would not be achievable. Additionally, if these 

dates were to slip, FAA officials noted that parts availability for 

maintaining existing VORs would become an increasing problem, 

further challenging FAA’s ability to maintain this aging equipment.

As figure 5 shows, the funding for NextGen capital improvements has 

generally been growing since fiscal year 2007, while funding for existing 

systems has gradually decreased (fig. 6). According to FAA’s latest 

facilities and equipment funding estimates for fiscal years 2014 through 

2017, FAA expects funding for existing systems to continue to decline, 

accounting for about 57 percent of the total funding for its capital plan in 

fiscal year 2017.

FAA’s Budget Process 

Lacks Sufficient Data 

to Determine Future 

Operations and 

Maintenance Needs 

and Priorities

Better Data Could 

Help FAA Prioritize 

Competing Deferred 

Maintenance and NextGen 

Resource Demands
 

Page 34 GAO-13-693 National Airspace System

Figure 6: Estimated and Actual Facilities and Equipment Funding Levels for NextGen and Existing Systems, Fiscal Years 

2007–2017

Note: Data for fiscal years 2007 through 2013 reflect the appropriated amounts while the data for 

fiscal years 2014 through 2017 are the latest available budget estimates.

While FAA’s capital plan reflects the agency’s priorities based on the 

facilities and equipment funding that it receives in a given year, better 

data on the condition of its infrastructure, as previously noted, could help 

FAA prioritize the competing resource demands of existing systems and 

facilities and NextGen deployment. Through its annual capital planning 

efforts, FAA determines how it will prioritize investments, given available 

funding.55

 

55FAA annually prepares a comprehensive capital investment plan, as required by 

provisions in legislation. This plan describes the planned capital investments for the next 5 

years consistent with the amount requested in the President’s annual budget submission 

and outyear funding estimates. As of July 2013, FAA has yet to release its fiscal years 

2014—2018 capital investment plan. According to FAA officials, the plan is under review, 

but there is no timetable for its release.

This plan, however, does not include data on the breadth of 
 

Page 35 GAO-13-693 National Airspace System

deferred maintenance facing those systems and infrastructure that will 

have to be maintained for many years during the transition to NextGen. 

FAA’s efforts to develop a plan to address significant deferred 

maintenance for both existing FAA systems and facilities could provide a 

more complete picture on FAA’s deferred maintenance and sustainment 

priorities through the transition to NextGen. As we previously mentioned, 

more sufficient data on FAA’s infrastructure could support efforts to 

establish maintenance priorities as well as facilities and equipment 

investment decisions. Furthermore, if the agency is faced with reduced 

funding levels—a possibility given the current fiscal environment and the 

Balanced Budget and Emergency Deficit Control Act56—then FAA efforts 

to establish priorities would become critical in mitigating budget shortfalls. 

Recently, FAA tasked the NextGen Advisory Committee to review current 

FAA plans and activities that have an effect on NextGen implementation 

and develop a prioritized list of activities, which can assist in the agency’s 

efforts to prioritize resources in a constrained budget environment.57

Weighing the priorities of existing systems and facilities and NextGen 

programs, however, could become increasingly difficult as FAA’s 

decisions on how long to maintain existing systems are evolving and 

could require investment in these systems for longer than initially 

anticipated. For example, FAA plans to maintain more existing radar sites 

for a longer time frame than it originally anticipated. Specifically, FAA 

initially planned to retain all of its primary surveillance radar sites for 

national security purposes and decommission all of its secondary 

surveillance radars and surface surveillance radar sites once ADS-B was 

deployed. However, after FAA completed a study examining alternative 

backup strategies for ADS-B in 2008, the agency decided that it would 

need to maintain roughly half of its secondary surveillance radar sites as 

backup for ADS-B. This decision was based on safety and security 

concerns—GPS signals can be susceptible to disruptions from 

atmospheric effects, signal blockage from buildings, and interference from 

 

56The Balanced Budget and Emergency Deficit Control Act (BBEDCA) established 

discretionary spending limits for fiscal years 2012 to 2021. 2 U.S.C. § 901, as amended. 

57The NextGen Advisory Committee is comprised of aviation stakeholders from the 

government and industry. The committee works to develop a common understanding of 

priorities in the context of overall NextGen capabilities and implementation constraints, 

with an emphasis on improvements through 2018. The committee primarily focuses on 

implementation issues, including prioritization criteria at a national level, joint investment 

priorities, and location and timing of capability implementation.
 

Page 36 GAO-13-693 National Airspace System

communications equipment, as well as from deliberate acts—and FAA 

plans to design, test, and deploy a new generation radar to serve as 

backup. As a result, the agency expects to continue operating 

approximately 420 primary radar sites through at least 2020 and maintain 

many of its ground-based radar sites as a backup system beyond 2030 

(see fig. 7). FAA will then face decisions on whether and for how long to 

continue upgrading existing radar sites or when and how many new 

generation radars will need to be deployed to serve as a system back-up. 

In addition, if FAA does not obtain stakeholder buy-in or funding for its 

efforts to reduce the VOR network within planned timeframes, the agency 

will have to continue maintaining this network until these issues are 

resolved. As previously noted, decisions related to upgrading and 

modernizing existing equipment and facilities will have to be balanced 

with NextGen and ATO Program Management Organization priorities, all 

of which could be competing for potentially declining resources in future 

years. Over the past 2 years, competing resource demands have resulted 

in FAA’s delaying investment in the development, testing, and evaluation 

of some NextGen and NextGen-related programs, a deferral that could 

ultimately lead to delaying the implementation of various NextGen 

systems that depend on those programs.

Figure 7: Federal Aviation Administration’s Planned Transition for Surveillance Capabilities, 2012
 

Page 37 GAO-13-693 National Airspace System

In addition, FAA’s resolution of how NextGen service contracts will be 

treated in the budget could also put pressure on FAA’s future facilities 

and equipment resource demands, adding to the agency’s challenges in 

establishing funding priorities. For example, two key NextGen programs—

ADS-B and Data Communications (DataComm)58—are in varying stages 

of development and deployment and are under performance-based 

service contracts. These two key programs are currently funded through 

FAA’s facilities and equipment account since the programs are still being 

developed and installed. According to FAA officials, the agency is still 

determining how these contracts will be treated in the budget after these 

systems are deployed and operational. Under FAA’s accounting 

procedures, even after a program under a service contract has been 

deployed, the vendor’s operation and maintenance cost attributed to the 

equipment are paid from the facilities and equipment account. FAA 

currently estimates the life cycle operations and maintenance costs for 

both ADS-B and DataComm will be roughly $141 million to $175 million 

per year once these systems are deployed.59

FAA’s operations account—which pays for the ongoing operations and 

maintenance of the existing systems—grew $3.6 billion, or 62 percent, 

from fiscal years 2000 through 2013 (fig. 8). However, the authorized 

levels for FAA’s fiscal years 2013 through 2015 operations funding 

roughly maintain the fiscal year 2012 levels—around $9.5 billion to $9.7 

billion.

Paying these costs from the 

facilities and equipment account—which, as previously noted, received 

$2.7 billion in fiscal year 2012—however, may limit the availability of 

funding for new capital acquisitions.

 

58DataComm is planned provide capabilities for pilots and controllers to transmit digital 

messages and will eventually replace the analog voice communication system currently in 

use.

59FAA estimates that the recurring life cycle operations and maintenance costs for both 

ADS-B and DataComm to be $141 million per year for 2015 through 2019 and $175 

million for 2020 through 2024.

FAA’s Budget Process Does 

Not Adequately Plan for 

the Costs of Operating and 

Maintaining Two Systems 

through the Transition
 

Page 38 GAO-13-693 National Airspace System

Figure 8: The Federal Aviation Administration’s (FAA) Enacted Budget Authority for the Operations Account Fiscal Years 

2000–2013

Note: Budget authority is authority provided by federal law to enter into financial obligations that will 

result in immediate or future outlays involving federal government funds. GAO, A Glossary of Terms 

Used in the Federal Budget Process, GAO-05-734SP (Washington, D.C.: Sep. 2005).

Unlike for the capital plan, FAA does not generate projections of future 

operating costs for its annual operations account. FAA’s life-cycle cost 

estimates for its major acquisitions—which FAA requires as part of its 

acquisition process—provide some indication of how FAA’s operations 

and maintenance costs are expected to grow in the coming years.60

 

60As we found in 2012, the Office of Management and Budget prepares estimates of 

FAA’s outyear budget authority for each account, including operations. Since these 

estimates are based on inflation adjustments and other factors, the estimates for FAA’s 

fiscal years 2016 to 2021 expenditures was projected to increase roughly at the forecast 

rate of GDP growth—around 2.3 percent to 2.5 percent annually. GAO, Airport and Airway 

Trust Fund: Factors Affecting Revenue Forecast Accuracy and Realizing Future FAA 

Expenditures, 

For 

example, as shown in figure 9, FAA estimates that operations and 

maintenance costs for existing systems for fiscal years 2013 through 

2017 will be 20 times greater than the operations and maintenance for 

GAO-12-222 (Washington, D.C.: Jan. 23, 2012).
 

Page 39 GAO-13-693 National Airspace System

NextGen systems over that same time period, given that few NextGen 

systems will be operational through 2017. However, as more NextGen 

systems become operational, the associated operations and maintenance 

costs of those systems will add to the amounts shown.61 FAA expects 

operations and maintenance costs for existing systems to continue for the 

foreseeable future since current NextGen plans do not show significant 

discontinuing or decommissioning of existing systems at least through 

2025.62

 

61These estimates only include those NextGen programs that have been “baselined” (i.e., 

those programs whose estimated schedules and budgets have received FAA executive 

approval), meaning that the operations and maintenance costs, particularly for the outyears, could be higher. 

62According to FAA’s plans, FAA is not making any additional decision on discontinuing or 

decommissioning existing systems until 2016 when it may decide how many instrument 

landing systems to maintain. Once those decisions are made, it can take years to develop 

and implement plans to discontinue these systems.
 

Page 40 GAO-13-693 National Airspace System

Figure 9: The Federal Aviation Administration’s (FAA) Projected Operations and 

Maintenance Costs for Baselined Existing and NextGen Programs, Fiscal Years 

2013–2017 and 2018 and Beyond

Note: These estimates reflect the operations and maintenance lifecycle costs of acquisition programs 

that have been baselined as of May 2013. A baselined program refers to a program with an estimated 

schedule and budget that has received FAA executive approval. The NextGen operations and 

maintenance lifecycle cost estimates do not include future NextGen systems, such as NextGen 

Weather and Voice Switch, because these programs are in the early stages of development and the 

acquisition process. Also, because programs have different lifecycle timeframes, FAA’s data does not 

identify a specific ending date because the data are aggregated across numerous programs.

While the data on lifecycle operations and maintenance costs give some 

indication of future operation and maintenance costs, FAA has not 

determined how these costs might be absorbed, particularly if it faces 

slow growing or reduced budgets in the years to come and has to 

maintain a growing number of systems as NextGen is deployed. In fiscal 

year 2012, over three-fourths, or $7 billion, of FAA’s operations account 

went to ATO to operate and maintain the national airspace system (see 

fig. 10). Within ATO’s portion, nearly 90 percent went to compensation 

and benefits costs ($5 billion) and fixed costs ($1.2 billion), such as 

building leases, utilities, and telecommunications costs. The remaining 
 

Page 41 GAO-13-693 National Airspace System

roughly $600 million went to non-fixed costs, including system and 

facilities maintenance and engineering services. According to FAA 

officials, when budget reductions occur, non-fixed costs, including those 

for maintenance, are reduced in order to continue funding fixed costs, 

which cannot be immediately adjusted because of the potential need for 

contract renegotiations with third parties outside FAA, transition and 

termination costs, and coordinated reductions for related system 

requirements. For example, when resources became constrained in 2013, 

FAA officials noted that they focused on maintaining equipment at the 

airports with the most significant activity and impact on the national 

airspace system and reduced its preventive maintenance and equipment 

support for all equipment in the national airspace system, until the agency 

was provided flexibility to transfer resources.63

 

63The Reducing Flight Delays Act of 2013 allowed DOT to transfer funds from AIP to avoid 

air traffic controllers’ furloughs and reduce the impacts of other reductions. Pub. L. No. 

113-9, § 2, 127 Stat. 443, 444.
 

Page 42 GAO-13-693 National Airspace System

Figure 10: The Federal Aviation Administration’s (FAA) Operations Funding and the Air Traffic Organization’s (ATO) Portion 

of This Funding, Fiscal Year 2012

Note: FAA’s operations account funds the recurring cost of annual administrative, operating and 

maintenance expenses for conducting the agency’s business, which includes the operation and 

maintenance of the air-traffic control system, employee compensation and benefits, and safety 

inspections. As noted in the report, ATO’s non-compensation fixed costs include building leases, 

utilities, and telecommunications costs while its non-compensation, non-fixed costs include system 

and facilities maintenance and engineering services, among other expenses. Also, according to FAA, 

ATO set asides reflect operational budget items that are centrally billed and monitored and are not 

distributed throughout the ATO service units’ budgets.

FAA has begun efforts to improve its operations account formulation. In 

2012, the ATO established an operations review board consisting of staff 

from various ATO offices to develop and institutionalize a more 

centralized, program-oriented, and repeatable operations budget process, 

beginning with the fiscal year 2013 operations budget. According to FAA 

officials involved with the board’s process for fiscal year 2013, this 
 

Page 43 GAO-13-693 National Airspace System

process enabled officials to identify a number of additional issues with 

FAA’s operations budget process, including uncoordinated and poorly 

planned decisions that lead to future budget liabilities. In September 

2012, the board made several recommendations to the ATO Chief 

Operating Officer, including:

• developing a 5-year operations budget that will include operations 

estimates for all capital programs to ensure a better link between the 

capital and operations portions of the budget;

• implementing controls to strengthen budget formulation and 

execution, such as mandating that all decisions on requirements that 

create operations budget liabilities beyond the current fiscal year be 

made at an executive level;

• requiring the board’s review of capital programs going to FAA’s Joint 

Resources Council64

• better integrating NextGen life-cycle-planning costs with operations 

budget formulation; and

for final investment decision or baseline change;

• establishing spending plans and periodically reporting on spending 

levels.

FAA has yet to institute these recommended changes that could help the 

agency better link its capital plans with future operations costs and 

mitigate potential budget shortfalls. As of March 2013, FAA officials said 

that they had done some work on planning for their fiscal year 2014 

operations budget and started work on formulating their 2015 operations 

budget but put these efforts on hold while working to address sequester 

activities.65

 

64The Joint Resources Council is an FAA executive body consisting of associate and 

assistant administrators, acquisition program executives, the Chief Financial Officer, the 

Chief Information Officer, and legal counsel. The JRC makes executive-level decisions, 

including those that determine whether a program meets a mission need and should 

proceed.

Officials were unclear when they would address the issues the 

board identified. Our prior work has noted the importance of developing 

information on long-term operations and maintenance resource needs to 

help decision makers determine whether these needs are adequately 

65BBEDCA also required the Office of Management and Budget to calculate, and the 

President to order, a sequestration, i.e., cancellation, of budgetary resources on March 1, 

2013. See 2 U.S.C. § 901a. For fiscal year 2013, the President ordered a sequestration of 

about $85 billion. Sequestration Order for Fiscal Year 2013 Pursuant to Section 251A of 

the Balanced Budget and Emergency Deficit Control Act, As Amended, 78 Fed. Reg. 

14633 (Mar. 6, 2013).
 

Page 44 GAO-13-693 National Airspace System

planned for and funded.66 Without a more visibility into current and future 

operations resource estimates, such as that envisioned in the board’s 

recommendations, FAA cannot effectively help Congress weigh priorities 

and assess budget trade-offs, such as those related to concurrently 

operating and maintaining existing and NextGen systems, if faced with 

declining budget resources.

After almost 10 years of planning and developing NextGen, FAA is 

implementing key NextGen systems and capabilities. Both the magnitude 

of the multi-year transition itself, as well as the numerous efforts under 

way throughout FAA to effectuate that transition, will require FAA to 

manage all aspects of NextGen in a strategic, timely, and coordinated 

fashion. To support a more coordinated and strategic approach, FAA 

needs to clearly define NextGen leadership roles and follow through on its 

efforts to fully populate the NextGen integrate master schedule—which 

can support real-time monitoring of the overall NextGen effort. FAA’s 

efforts to identify the roles its facilities and workforce will play in NextGen 

and determine how best to train its personnel to undertake new or 

changed responsibilities are also ongoing. Addressing these transition 

challenges is important not only to the successful transition to NextGen, 

but also to avoid extended reliance on the aging legacy equipment and 

systems. Specifically, FAA must follow through on planned efforts to 

integrate near- and long-term efforts to realign and consolidate facilities 

with its plans to maintain existing facilities as well as discontinue the use 

of systems facing significant sustainment issues or that are no longer 

needed as NextGen capabilities are deployed. Failure to follow through 

on these efforts means that FAA will miss potential opportunities to 

reduce its overall maintenance costs at a time when resources needed to 

maintain both systems will become scarcer, particularly if some facilities 

and systems are not discontinued or decommissioned.

Meanwhile, FAA reports that it continues to maintain the current air traffic 

control system at an operational availability level that exceeds 99 percent. 

However, this metric does not really illustrate the underlying performance 

and condition of all of FAA’s air traffic control systems, some of which 

have experienced increasing outages, yet need to be maintained for 

 

66GAO, Embassy Construction: State Has Made Progress Constructing New Embassies, 

but Better Planning Is Needed for Operations and Maintenance Requirements, 

GAO-06-641 (Washington, D.C.: June 30, 2006).

Conclusions 
 

Page 45 GAO-13-693 National Airspace System

another 10 years or more. FAA collects additional metrics and information 

on the entire system that shows that its existing equipment is aging and 

has mounting maintenance requirements, but this information is limited, 

and the condition of the majority of FAA’s unstaffed infrastructure and 

facilities is unknown, and therefore, the costs of deferred maintenance for 

these systems is only known within a rough order of magnitude. Without 

more information on the condition of its existing infrastructure and the size 

of its maintenance backlog, FAA is limited in its ability to estimate or 

control the costs to operate and maintain the existing systems during the 

NextGen transition, particularly since systems that were initial planned to 

be discontinued could continue on for many years, due to delays in 

NextGen implementation as well as difficulties associated with obtaining 

agreement from stakeholders to shut down those systems. 

Since 2000, FAA has seen about a 60 percent growth in its overall 

budget, driven by a roughly 60 percent growth in its operations budget, 

but current law suggests reduced federal spending levels going forward 

are possible. Should FAA face reduced funding, while its operations and 

maintenance costs rise, along with its funding needs to support NextGen 

implementation, FAA will face difficult choices about how to allocate its 

available resources. FAA has a capital plan that outlines projects and 

related funding over a 5-year period that it adjusts on an annual basis to 

changes in funding levels. FAA does not, however, have a similar plan to 

help the agency plan for operating costs in future years, including the 

potential impact of future systems that will be deployed and the need for 

continued operations and maintenance of existing systems. FAA’s ATO

operations review board recognized the limitations in FAA’s management 

of its operations budget and made several recommendations to FAA’s 

ATO Chief Operating Officer to improve FAA’s budgeting process, 

including developing a 5-year operations plan. However, FAA officials 

have delayed implementation and have not identified a timeframe for 

returning to the board’s recommendations. Better planning of the 

operations budget could help FAA position itself to make effective 

decisions on how to balance the maintenance costs required to continue 

operating existing systems during the transition to NextGen as well as 

fund the operations and maintenance costs associated with the new 

NextGen systems that will be deployed. In addition, improved budget 

planning and more sufficient data on infrastructure condition could help 

Congress better understand the funding requirements of existing systems 

and facilities and facilitate FAA’s efforts to support the agency’s mission 

of continuing to operate a safe aviation system along with the longerterm goal of transforming the system to NextGen.
 

Page 46 GAO-13-693 National Airspace System

To improve FAA’s efforts to manage the transition between the existing 

air traffic control and NextGen systems, GAO recommends that the 

Secretary of Transportation direct the Administrator of FAA to develop a 

strategy for implementing the ATO operations review board 

recommendations, such as developing a 5-year operations plan that 

better identifies the operations and maintenance costs associated with 

existing and NextGen systems, establish a timeline for this effort, and 

ensure that sufficient data, including data on the condition of unstaffed 

infrastructure, are available to support establishing agency priorities.

We provided the Department of Transportation (DOT) with a draft of this 

report for review and comment. DOT responded by email and did not 

agree or disagree with our recommendation, but provided technical 

clarifications, which we incorporated into the report as appropriate.

Recommendation for 

Executive Action

Agency Comments
 

Page 47 GAO-13-693 National Airspace System

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 the 

Department of Transportation, the appropriate congressional committees, 

and other interested parties. In addition, the report will be available at no 

charge on the GAO website at http://www.gao.gov. 

If you or your staff members have any questions about this report, please 

contact me on (202) 512-2834 or at dillinghamg@gao.gov. 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 III.

Gerald L. Dillingham, Ph.D.

Director, Physical Infrastructure Issues
 

Page 48 GAO-13-693 National Airspace System

List of Requesters

The Honorable John D. Rockefeller IV

Chairman

Committee on Commerce, Science, and Transportation

United States Senate

The Honorable John Thune

Ranking Member

Committee on Commerce, Science, and Transportation

United States Senate

The Honorable Bill Shuster

Chairman

Committee on Transportation and Infrastructure

House of Representatives

The Honorable Frank A. LoBiondo

Chairman

Subcommittee on Aviation

Committee on Transportation and Infrastructure

House of Representatives

The Honorable Rick Larsen

Ranking Member

Subcommittee on Aviation

Committee on Transportation and Infrastructure

House of Representatives

The Honorable Lamar Smith

Chairman

Committee on Science, Space, and Technology

House of Representatives

The Honorable Eddie Bernice Johnson

Ranking Member

Committee on Science, Space, and Technology

House of Representatives

The Honorable Ralph Hall

House of Representatives 
 

Page 49 GAO-13-693 National Airspace System

The Honorable Thomas E. Petri

House of Representatives
Appendix I: Scope and Methodology

Page 50 GAO-13-693 National Airspace System

To determine the Federal Aviation Administration’s (FAA) progress in 

addressing past challenges affecting its ability to execute the transition to 

the Next Generation Air Transportation System (NextGen), we reviewed 

prior GAO reports to help identify key challenges that FAA has faced in 

developing and implementing NextGen, including (1) sustained 

leadership; (2) managing NextGen interdependencies; (3) equipping 

aircraft with NextGen technologies; (4) preparing FAA’s workforce; and 

(5) consolidating and realigning FAA’s facilities sustained leadership. To 

identify FAA’s efforts to address these challenges, if any, we assessed 

FAA’s NextGen planning documents, including the NextGen Enterprise 

Architecture and the 2012 and 2013 NextGen Implementation Plans, 

relevant legislation, and other agency-provided documentation on its 

NextGen acquisitions, workforce planning, and facilities consolidation 

efforts. We interviewed FAA officials from various offices within the Air 

Traffic Organization (ATO) and NextGen Organization to clarify our 

understanding of the information presented in these documents and 

identify any actions that the agency planned to take in response to these 

challenges. We also interviewed representatives with the National Air 

Traffic Controllers Union (NATCA) and Professional Aviation Safety 

Specialists (PASS)—the employee unions representing FAA controllers 

and technicians—to discuss FAA’s efforts to address workforce 

challenges.

To identify changes in the performance and condition of existing air traffic 

control systems and facilities, we reviewed FAA’s annual Performance 

and Accountability Reports to identify FAA’s publicly-reported 

performance measure—operational availability of the air-traffic control 

system—and changes in the performance of that measure. To obtain a 

fuller picture of overall system performance, we obtained and analyzed 

data on the number and duration of unscheduled and scheduled outages 

for FAA’s air traffic control systems for fiscal years 2001 through 2012. 

We also obtained data from FAA on the condition of its staffed and 

unstaffed facilities and infrastructure supporting these systems. We 

reviewed agency-prepared documents, such as assessments on the 

condition on system performance and maintenance requirements for 

individual air traffic control systems, and interviewed FAA officials in 

Washington, D.C., and Oklahoma City, Oklahoma, responsible for 

maintaining FAA’s air traffic control systems and facilities to understand 

FAA’s measures of system performance and facility and infrastructure 

condition and reasons for any changes in these measures. We also 

assessed the reliability of the system performance and infrastructure 

condition data by reviewing relevant documentation, such as procedures 

and controls for collecting and verifying the data, and interviewing agency 

Appendix I: Scope and Methodology
Appendix I: Scope and Methodology

Page 51 GAO-13-693 National Airspace System

officials. Except where noted in the presentation of the data, we 

determined these data were of sufficient quality to be used for the 

purposes of this report. To determine FAA’s efforts to address 

maintenance requirements of existing systems and infrastructure, we 

reviewed FAA maintenance policies and other documents describing the 

agency’s approach to maintaining existing systems and facilities and 

discontinuing obsolete systems and facilities. We interviewed FAA 

officials responsible for the maintaining these systems and facilities, FAA 

officials responsible for developing plans to discontinue the use of 

obsolete systems, NATCA, and PASS to further discuss FAA’s approach.

To determine the extent to which FAA has planned for the financial 

resources to sustain existing systems and facilities and the NextGen 

transition, we analyzed FAA budget data from fiscal year 2000 through 

fiscal year 2012 to identify trends in FAA’s capital and operations funding. 

We reviewed FAA’s budget justifications and the latest version of FAA’s 

capital improvement plan for fiscal years 2013 through 2017 to identify 

projected capital spending levels. We also analyzed FAA’s life-cycle cost 

estimates for its major acquisition programs to identify potential future 

operations and maintenance costs. We reviewed FAA briefings and other 

documents and interviewed FAA ATO, budget, and financial officials on 

FAA’s capital and operations budget planning efforts, including the efforts 

of the ATO operations review board. We updated our prior assessments 

on the reliability of the budget and acquisition data by reviewing relevant 

documentation and determined that these data were of sufficient quality 

to be used for the purposes of this report.

We conducted this performance audit from January 2012 to August 2013 

in accordance with generally accepted government auditing standards. 

Those standards require that we plan and perform the audit to obtain 

sufficient, appropriate evidence to provide a reasonable basis for our 

findings and conclusions based on our audit objectives. We believe that 

the evidence obtained provides a reasonable basis for our findings and 

conclusions based on our audit objectives.
Appendix II: Status of NextGen Acquisition 

Programs, as of June 2013

Page 52 GAO-13-693 National Airspace System

Table 3: Status of NextGen Programs with Baselined Segments

Program Segment/Phase

Projected cost 

(in millions) Start date

Completion 

date 

On time 

and budget 

per FAA?

Automatic Dependant 

Surveillance-Broadcast

Segment 1-2 $1,726 2007 2014 Yes

Collaborative Air Traffic 

Management Technologiesa 

Work package 1-3 $567 2005 2015 Yes

Data communications Segment 1, phase 1 $741 2012 2019 Yes

System Wide Information 

Management Systemb

 

Segment 1-2A $430 2009 2017 Yes

Source: GAO analysis of FAA documents.

Note: A “baselined” program refers to a program with an estimated schedule and budget that has 

received FAA executive approval. This information is based on the most recent information from FAA 

and is subject to change.

a

Work package 4 is estimated to begin in 2015.

b

Segment 2B is estimated to begin in 2014.

Table 4: Status of NextGen Programs without Baselined Segments

Program Estimated start date as of June 2013

Common Support Services—Weathera 2014

NextGen Future Facilities, Segment 1 To be determinedb

National Airspace System Voice Systems, Segment 2c 2014

NextGen Weather Processor 2014

Source: GAO analysis of FAA documents.

Note: Cost and completion date information is not available until the program has officially started.

a

This program was previously known as NextGen Network Enabled Weather.

b

As previously noted, in light of current budget constraints, FAA is assessing options for moving 

forward.

c

According to FAA, the first segment of this program involves testing that will be used to conduct the 

investment analysis activities to support the final investment decision for segment 2.

Appendix II: Status of NextGen Acquisition 

Programs, as of June 2013
Appendix III: GAO Contact and Staff 

Acknowledgments

Page 53 GAO-13-693 National Airspace System

Gerald L. Dillingham, Ph.D., (202) 512-2834, or dillinghamg@gao.gov

In addition to the individual named above, Heather Krause, Assistant 

Director; Kevin Egan; Carol Henn; Bert Japikse; Delwen Jones; Bonnie 

Pignatiello Leer; SaraAnn Moessbauer; Dominic Nadarski; and Josh 

Ormond made key contributions to this report.

Appendix III: GAO Contact and Staff 

Acknowledgments 

GAO Contact

Staff 

Acknowledgments 

(540238)
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