TACTICAL AIRCRAFT

Comparison of F-22A 

and Legacy Fighter 

Modernization 

Programs

Report to the Subcommittee on 

Defense, Committee on Appropriations, 

U.S. Senate

April 2012

GAO-12-524

United States Government Accountability Office

GAO
United States Government Accountability Office

Highlights of GAO-12-524, a report to the 

Subcommittee on Defense, Committee on 

Appropriations, U.S. Senate 

April 2012 

TACTICAL AIRCRAFT 

Comparison of F-22A and Legacy Fighter 

Modernization Programs

Why GAO Did This Study

The Air Force expects to invest a total 

of $9.7 billion in F-22A modernization

through 2023. The Air Force and Navy 

have modernized many of their fighter

and attack aircraft over the past 

several decades. Given this historical 

experience and concerns about the 

mounting cost of F-22A modernization,

GAO was asked to examine the history 

of the modernization programs of the 

F-15, F-16, and F/A-18, and compare 

those legacy programs with the F-22A 

modernization program.

To identify differences and similarities 

between the F-22A modernization 

program and those of the selected 

legacy programs, GAO reviewed 

official service history documents and

current and historical program 

documents; analyzed program cost, 

schedule, performance, and quantity 

data; and spoke with current and 

former Air Force, Navy, and contractor 

officials. 

DOD reviewed a draft of this report and 

had no formal written comments.

What GAO Found

The F-22A and legacy modernization programs GAO reviewed were rooted in 

different development strategies. The F-22A began as a single-step program and 

did not anticipate the need for future modernization, while the legacy programs 

each began with the expectation that their aircraft would be incrementally 

upgraded over time. F-22A modernization began in reaction to a major shift in the 

aircraft’s basic mission, which required the development of new capabilities that 

had not been planned for as part of the initial development program. In contrast, 

the legacy modernization programs made planned incremental improvements to 

existing mission capabilities. All of the modernization programs began at about 

the same time in development and procurement. The F-22A program is 

developing and retrofitting new capabilities onto a complex stealth aircraft, which 

is costly—currently estimated at $9.7 billion total. Legacy modernization 

programs were less complex, and thus less costly, and incorporated mature 

technologies onto new production aircraft. Accurately identifying and comparing 

the total cost of each modernization program is difficult. Each of the programs, 

including the F-22A, initially managed and funded modernization as a 

continuation of its baseline program, so modernization costs and funding were 

not clearly identified in selected acquisition reports or budget documents. 

Comparison of the Differences and Similarities among Modernization Programs 

Legacy aircraft F-22A 

Differences

Initial development was incremental with plans to 

increase capabilities over time 

Initial development was single-step with no plans 

for future incremental upgrades 

Initial development took 5 to 7 years Initial development took 14 years

Ultimately procured thousands of aircraft Ultimately procured 179 aircraft 

Proactively modernized as requirements evolved 

and new technologies matured 

Reactively modernized when a new mission was 

added 

Incorporated upgrades into production lines and 

delivered new upgraded aircraft 

Retrofitting upgrades into fielded aircraft because 

production has ended 

Conventional aircraft designs and federated 

avionics reduced complexity and costs

Stealth aircraft design and integrated avionics 

make retrofits complex and costly 

Similarities

Began modernizing with more than 85 percent of estimated development costs funded 

Began modernizing with less than 33 percent of estimated procurement costs funded

Began modernizing with less than 20 percent of estimated procurement aircraft purchased

a

Managed modernization as a continuation of the original development program

a

Began modernizing while in production and around the time of initial operating capability

b

Source: GAO. 

a

The F-15 program was further into procurement when it began modernizing. 

View b

Later increments of the F/A-18 program were funded and managed as distinct acquisition efforts, 

and the F-22A is planning to fund and manage Increment 3.2B as its own acquisition effort. 

GAO-12-524. For more information, 

contact Michael Sullivan at (202) 512-4841 or 

sullivanm@gao.gov. 
Page i GAO-12-524 F-22A Modernization Comparison

Letter 1 

Background 2

F-22 and Legacy Modernization Programs Took Different 

Approaches to Developing and Fielding Capabilities 3

Concluding Observations 14

Agency Comments 15

Appendix I Scope and Methodology 17

Appendix II System Modernization Summaries 19

Appendix III GAO Contact and Staff Acknowledgments 39

Related GAO Products 40

Tables

Table 1: Comparison of the Differences and Similarities among 

Modernization Programs 4

Table 2: Cumulative Cost, Quantity, and Capability Increments over 

20 Years Following Development Start 8

Figures

Figure 1: Comparison of Investment Progress Prior to 

Modernization 12

Figure 2: F-22A Raptor 20

Figure 3: F-22A Modernization Timeline 21

Figure 4: F-15 Eagle/Strike Eagle 24

Figure 5: F-15 Modernization Timeline 25

Figure 6: F-16 Fighting Falcon 28

Figure 7: F-16 Modernization Timeline 30

Figure 8: F/A-18 Hornet/Super Hornet/Growler 34

Figure 9: F/A-18 Modernization Timeline 35

Contents
Page ii GAO-12-524 F-22A Modernization Comparison

Abbreviations

DOD Department of Defense

HARM High-speed Antiradiation Missile

IOC initial operating capability

LANTIRN Low Altitude Navigation and Targeting Infrared for Night

MSIP Multinational Staged Improvement Program

OSD Office of the Secretary of Defense

PEP-2000 Production Eagle Package-2000

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Page 1 GAO-12-524 F-22A Modernization Comparison

United States Government Accountability Office 

Washington, DC 20548

April 26, 2012

The Honorable Daniel K. Inouye

Chairman

The Honorable Thad Cochran

Ranking Member

Subcommittee on Defense

Committee on Appropriations

United States Senate

The Air Force currently expects to invest a total of $9.7 billion in its F-22A 

modernization program from 2003 through 2023.

1

To conduct our work we reviewed historical documents and data and 

discussed the development and modernization programs of the F-22A, as 

well as the F-15, F-16, F/A-18, and F-117A with current and former 

service and contractor officials. According to the service officials we 

spoke with, modernization is generally a process whereby upgrades and 

modifications are made in response to new requirements and to capitalize 

on advances in technology to increase an aircraft’s capabilities over time. 

To better understand the overall development approach of each program, 

we reviewed selected acquisition reports

Fighter aircraft 

modernization is not new within the Department of Defense (DOD). In 

fact, the Air Force and Navy have modernized many of their fighter and 

attack aircraft over the past several decades. Given this historical 

experience, and citing the mounting cost and timing of F-22A 

modernization, you requested that we examine the history of the 

modernization programs of the F-15, F-16, F/A-18, and F-117A, and 

compare those legacy programs with the F-22A modernization program. 

In response, this report identifies and discusses key differences and 

similarities in the F-22A modernization strategy and those of the legacy 

programs you identified.

2

 

1 In addition, the Air Force also expects to invest nearly $2 billion in F-22A reliability 

improvements from 2003 through 2023. 

, budget documents, program 

briefings, acquisition decision memorandums, official service history 

2 Selected acquisition reports are key recurring summary status reports to the Congress 

on the cost, schedule, and performance of DOD’s major defense acquisition programs. 10 

U.S.C. § 2432.

 
 

Page 2 GAO-12-524 F-22A Modernization Comparison

documents, prior GAO reports, and other pertinent documents. We met 

with, and in some cases reviewed the writings of, current and former Air 

Force, Navy, and contractor officials with firsthand knowledge of the 

programs we were reviewing in order to gain additional insights into 

when, why, and how they went about modernizing. In the course of our 

work, we talked with contractor and former program officials who provided 

limited insights into the initial development of the F-117A stealth aircraft. 

However, because of to the amount of time that had passed and the 

highly classified nature of the program, key documentation and data were 

not readily accessible. As a result, we were not able to collect sufficient 

information relevant to our reporting objectives and thus did not include 

the F-117A in this report. See appendix I for a more detailed discussion of 

our scope and methodology.

We conducted this performance audit from June 2011 to April 2012 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.

The Air Force’s F-22A Raptor is the only operational tactical aircraft 

incorporating a low observable (stealth) and highly maneuverable 

airframe, advanced integrated avionics, and a supercruise engine 

capable of sustained supersonic flight. The F-22A acquisition program 

began in 1991 with an intended development period of 12 years and 

planned a procurement of 648 aircraft. The system development and 

demonstration period eventually spanned more than 14 years, during 

which time threats, missions, and a number of requirements changed. As 

a result, development costs substantially increased and procurement 

quantities greatly decreased—resulting in the procurement of only 179 

aircraft, plus 9 development aircraft. The final aircraft is scheduled to be 

delivered in May 2012.

In 2003, the Air Force established a modernization program primarily to 

develop and insert new and enhanced ground attack capabilities that 

were considered necessary to meet current and future threats. The F-22A 

modernization program is broken into four phases, known as increments, 

with each phase being made up of multiple projects:

Background
 

Page 3 GAO-12-524 F-22A Modernization Comparison

• Increment 2, the initial phase of modernization, addressed some 

requirements deferred from the acquisition program and added new 

ground attack capability.3

• Increment 3.1 began fielding in November 2011 and adds enhanced 

radar and enhanced air-to-ground attack capabilities.

It has been fielded.

• Increment 3.2A is a software upgrade to increase the F-22A’s 

electronic protection, combat identification, and capability to receive 

data over DOD’s Link-16 data network.

• Increment 3.2B is expected to increase the F-22A’s geolocation, 

electronic protection, and Intra Flight Data Link capabilities and 

integrate AIM-9X and AIM-120D missiles.

Some of the key content originally planned for Increment 3.2B has been 

deferred, the estimated cost of the overall modernization program has 

doubled, and the schedule has slipped by 7 years—which program 

officials attribute to requirements and funding instability. The most recent 

program schedule indicates that 3.2B will begin fielding in 2017.

The F-22A and legacy modernization programs we reviewed were rooted 

in very different development strategies, although they shared some 

similar characteristics. These differences and similarities are summarized 

in table 1.

 

3 The Air Force numbering scheme considers Increment 1 to be the baseline capabilities 

delivered by the F-22A acquisition program.

F-22 and Legacy 

Modernization 

Programs Took 

Different Approaches 

to Developing and 

Fielding Capabilities
 

Page 4 GAO-12-524 F-22A Modernization Comparison

Table 1: Comparison of the Differences and Similarities among Modernization 

Programs 

Source: GAO.

a

The F-15 program was further into procurement when it began modernizing. 

b

Later increments of the F/A-18 program were funded and managed as distinct acquisition efforts, 

and the Air Force is planning to fund and manage F-22A Increment 3.2B as its own acquisition effort. 

The F-22A began as a single-step program and did not anticipate the 

need for significant future modernization. The legacy programs, on the 

other hand, began with the expectation that their aircraft would be 

incrementally upgraded and modified over time. F-22A modernization 

began in reaction to a major shift in the aircraft’s basic mission, which 

required the development of robust ground attack capabilities that were 

not part of the initial development program. In contrast, the legacy 

modernization programs were primarily initiated to make incremental 

improvements to existing mission capabilities. The F-22A and legacy 

modernization programs all began at about the same time in development 

and procurement. The F-22A program is more complex and costly than 

the legacy programs, primarily because the new capabilities have to be 

retrofitted onto complex, stealth aircraft that have integrated avionics 

systems, which, according to program and contractor officials, adds labor 

hours and cost. The current total estimated cost of F-22A modernization 

Legacy aircraft F-22A

Differences

Initial development was incremental with plans 

to increase capabilities over time

Initial development was single step with 

no plans for future incremental upgrades 

Initial development took 5 to 7 years Initial development took 14 years

Ultimately procured thousands of aircraft Ultimately procured 179 aircraft

Proactively modernized as requirements 

evolved and new technologies matured 

Reactively modernized when a new 

mission was added

Incorporated upgrades into production lines 

and delivered new upgraded aircraft

Retrofitting upgrades into fielded aircraft 

because production has ended

Conventional aircraft designs and federated 

avionics reduced complexity and costs

Stealth aircraft design and integrated 

avionics make retrofits complex and 

costly 

Similarities

Began modernizing with more than 85 percent of estimated development costs funded

Began modernizing with less than 33 percent of estimated procurement costs funded

Began modernizing with less than 20 percent of estimated procurement aircraft 

purchased

a

Managed modernization as a continuation of the original development program

a

Began modernizing while in production and around initial operating capability

b
 

Page 5 GAO-12-524 F-22A Modernization Comparison

is $9.7 billion. The legacy programs incorporated planned incremental 

upgrades into new production aircraft that had less complex avionics 

systems and were not required to be stealthy. Because the legacy 

programs managed and funded modernization as a continuation of their 

baseline programs, it is difficult to isolate and compare the full costs of 

modernization.

The Air Force did not expect any major shifts in the F-22A’s primary 

mission and thus did not plan for future modernization upgrades. From 

the outset, the Air Force’s F-22A development strategy was to pursue a 

quantum leap in capability in a single development program, referred to 

as a single-step approach, to develop and field a stealthy aircraft with 

advanced capabilities to replace its aging F-15C/D fleet and perform air 

superiority missions. Recognizing the magnitude of this development 

effort, the Air Force estimated that it would need more than 12 years to 

develop and deliver an initial F-22A operating capability.

In 2003, we testified that the Air Force took on significant risk and 

onerous technological challenges by committing to an approach to F-22A 

development that promised to deliver all of the required capabilities in a 

single step.4 We noted that while it may have allowed the F-22A program 

to compete for funding, it hamstrung the program with little knowledge 

about its true technology, funding, and schedule needs. In addition, the 

Air Force did not make early trade-offs between requirements and 

available resources and therefore never established an executable 

business case.5

In contrast, the legacy programs we reviewed approached development 

of their aircraft as an incremental process in which initial capabilities 

Ultimately F-22A development took more than 14 years, 

encountered significant cost increases and quantity reductions, and has 

not yet fully met established requirements, specifically those related to 

reliability and maintainability.

 

4 GAO, Best Practices: Better Acquisition Outcomes Are Possible If DOD Can Apply 

Lessons from F/A-22 Program, GAO-03-645T (Washington, D.C.: Apr. 11, 2003).

5 Based on GAO’s past work, a business case is defined as demonstrated evidence that 

(1) the warfighter need exists and that it can best be met with the chosen concept and 

(2) the concept can be developed and produced within existing resources—including 

design knowledge, demonstrated technologies, adequate funding, and adequate time to 

deliver the product.

Different Fundamental 

Development Strategies 

Laid Distinct Foundations 

for Modernization
 

Page 6 GAO-12-524 F-22A Modernization Comparison

would quickly be developed and fielded, and as requirements evolved 

and technologies became available, additional increments of aircraft 

would then be developed. All of the legacy programs encountered 

difficulties during their initial development programs, yet they all delivered 

initial increments of operational aircraft within 5 to 7 years. In some

cases, the initial aircraft provided only a limited operating capability 

because certain performance requirements could not be achieved. In 

most cases, the users deemed the limited capability acceptable, with the 

understanding that future increments of the aircraft could address the 

shortfalls. The following are illustrative examples from each program6

• F-15 Eagle: In the late 1960s, the Air Force identified the need to 

develop and field a new air superiority aircraft to counter emerging 

threats. The new aircraft, designated the F-15 Eagle, was expected to 

possess advanced capabilities, excel in close combat and 

maneuvering situations, and specialize in the tactical missions 

including escort and combat air patrol. Prior to the start of full-scale 

development in 1970, key decision makers made trade-offs, such as 

opting not to include 2,000 pounds of additional fuel capacity, to 

ensure that the program would be able to deliver a useful increment of 

capability within a relatively short time frame. Those early trade-offs 

were made with the understanding that the traded capabilities could 

potentially be added in the future if requirements demanded them and 

resources were available. While the F-15 development program was 

considered expensive relative to other programs at that time, and 

encountered significant difficulties with its engines, it was able to 

deliver an initial operating capability in 1975—5 years after the start of 

development—and quickly fielded hundreds of operational aircraft.

(see app. II for a more detailed discussion of each program):

• F-16 Fighting Falcon: The F-16 development program that began in 

1975 was essentially the continuation of a competitive prototype 

program that had been ongoing since 1972 known as the Lightweight 

Fighter Prototype program. In fact, the Lightweight Fighter Prototype 

program’s requirements document became the initial basis of the F-16 

full-scale development program. According to the requirements 

document, “the Air Force intend[ed] to investigate the feasibility and 

operational utility of highly maneuverable lightweight fighter aircraft 

 

6 In addition to the F-15, F-16, and F/A-18 programs, we were also asked to look at the 

F-117A program, but because sufficient historical documentation and data were not 

readily accessible it is not included here as an example. 
 

Page 7 GAO-12-524 F-22A Modernization Comparison

through a prototype design, fabrication, and flight test program.” In 

addition, the requirements emphasized the need for the aircraft to be 

“relatively low cost.” The Air Force also expected the F-16 to be the 

low-end complement to its high-end F-15 fleet. The program was 

designated as a design-to-cost effort, meaning that cost was the key 

requirement against which all other requirements were traded. As a 

result, the baseline F-16 aircraft—ultimately designated as F-16A/B—

were day-only, fair-weather fighters with relatively basic capabilities, 

although they did possess some more advanced capabilities like 

computer-aided flight controls known as fly-by-wire. The radar system 

in the initial F-16 aircraft did not fully meet performance specifications, 

and similar to the F-15, the aircraft had significant difficulties with its 

engine. Regardless, the Air Force delivered an initial operating 

capability just over 5 years after development start and quickly fielded 

hundreds of operational aircraft.

• F/A-18 Hornet: The Navy’s F/A-18 development program that began 

in 1975 was rooted in the Lightweight Fighter Prototype program. 

Despite direction to procure the same aircraft as the Air Force—the 

F-16—the Navy chose to develop its own unique fighter and attack 

aircraft, citing the need for two engines and other unique features that 

it believed were necessary to operate from an aircraft carrier. As a 

result, the Navy developed its own requirements and planned for a 

7-year development program that some documents indicate was also 

to be a design-to-cost program. According to current F/A-18 program 

officials, the Navy established a formal plan for future F/A-18 

improvements and upgrades at the time the development program 

began. While the baseline F/A-18 program was able to achieve initial 

operating capability in 1983, slightly later than originally planned, it did 

not fully meet its established requirements for combat radius or “bring 

back” capacity—that is, the capacity of the aircraft to return to the 

aircraft carrier with unused weapons and fuel. Program officials 

pointed out, however, that those capability shortfalls were deemed 

acceptable by the warfighters, and deferred into the future to allow for 

the production and fielding of hundreds of operational F/A-18A/B 

aircraft.

A comparison of data from F-22A, F-15, F-16, and F/A-18 selected 

acquisition reports at 5-year intervals over the first 20 years following the 

start of development for each program shows that the incremental 

development approaches of the legacy systems quickly produced large 

quantities of operational aircraft and introduced several new increments 

of aircraft over that time span (see table 2). The data also highlight the 

high cost—in comparable 2012 dollars—of the overall F-22A program 

relative to the legacy aircraft we reviewed, and the relatively low 
 

Page 8 GAO-12-524 F-22A Modernization Comparison

quantities of baseline aircraft that its single-step development approach 

produced over that same time frame.

Table 2: Cumulative Cost, Quantity, and Capability Increments over 20 Years 

Following Development Start 

Millions of 2012 dollars

Program Data type Year 5 Year 10 Year 15 Year 20

F-22A Cost $16,605.1 $30,329.9 $56,830.0 $74,632.5

Quantity 

(procured)

0 2 92 179

Increments 

(series) 

- A A A 

F-15 Cost $12,961.7 $33,265.8 $44,042.3 $56,787.7

Quantity 

(procured)

92 579 792 1,002

Increments 

(series) 

A/B A/B, C/D A/B, C/D A/B, C/D, E

F-16 Cost $10,109.6 $29,477.8 $51,315.9 $61,562.6

Quantity 

(procured)

250 989 1,859 2,201

Increments 

(blocks) 

5, 10, 15 25, 30/32 25, 30/32, 

40/42

25, 30/32, 40/42, 

50/52

F/A-18 Cost $5,788.3 $25,311.5 $41,750.9 $66,203.9a

Quantity 

(procured)

9 325 745 979

Increments 

(series) 

A/B A/B A/B, C/D A/B, C/D

Source: GAO analysis of DOD data.

a

a

Nearly $4 billion of the cumulative cost increase in the F/A-18 program between year 15 and year 20 

is directly attributable to the beginning of F/A-18E/F development, but because the F/A-18E/F had not 

been fielded as of year 20 it is not listed as a new Increment (series) in this table. 
 

Page 9 GAO-12-524 F-22A Modernization Comparison

The F-22A modernization program began in reaction to a significant 

change in the aircraft’s primary mission. In contrast, the legacy programs 

we reviewed established modernization requirements that focused on 

using mature technologies to upgrade the capabilities of their respective 

aircraft to better perform the missions for which they had been initially 

developed.7

F-22A modernization was initiated in 2003, in response to new 

requirements for the aircraft to perform ground attack missions in addition 

to the air supremacy missions it had originally been designed for. Given 

the magnitude of this shift in mission, and because the original 

development program had not anticipated the need for such a change, 

critical information about requirements, technical scope, schedule, and 

funding was not available at the time modernization began. As a result, 

the initial cost and schedule estimates for the overall modernization 

program were not fully informed—that is, they were not knowledge 

based—and have since changed significantly, with costs doubling and 

schedule slipping by more than 7 years.

The F-22A and legacy programs we reviewed all began 

modernizing when their respective development programs were either 

complete or nearing completion—around the time that the baseline 

program achieved initial operating capability—and nearly all of the 

programs were early in procurement, with the exception of F-15, which 

was further along.

Because the legacy programs anticipated future upgrades, they began 

planning and working with other program offices, contractors, and in 

some cases, foreign governments, to identify potential new technologies 

for future increments while their initial development programs were 

ongoing. In many cases, this collaborative approach allowed programs to 

leverage investments in new technology that had been made by other 

programs or even foreign governments that had purchased variants of the 

respective programs’ aircraft. The programs also worked closely with the 

warfighters to ensure that the technologies they were pursuing would 

provide new capabilities to address new requirements or would 

sufficiently enhance existing capabilities. In some cases, this approach 

required the warfighters to agree to eliminate or defer some desired 

 

7 The F-15E Strike Eagle and the EA-18G Growler are two cases where upgrades were 

driven by significant mission changes, similar to the F-22A. However, unlike the F-22A, 

those new F-15 and F/A-18 variants benefitted from knowledge gained through the 

operational use of hundreds of previously fielded aircraft.

Modernization Began for 

Different Reasons but at 

Similar Points in 

Development and 

Procurement
 

Page 10 GAO-12-524 F-22A Modernization Comparison

capabilities indefinitely because they were not technologically feasible or 

because they were not affordable. For example, former F-16 program 

officials explained that the warfighters had stated a desire to include the 

Low Altitude Navigation and Targeting Infrared for Night (LANTIRN) 

subsystem in the first major F-16 upgrade that was expected to provide 

aircrew with the ability to fly both day and night and in adverse weather, 

while improving terrain-following and targeting capabilities. However, the 

technology was not mature at the time and as a result the program office 

deferred the capability. The former officials noted that the F-16 eventually 

received LANTIRN as part of its Block 40/42 upgrade, but only after the 

technology had been matured for use on the F-15E.

While making these types of trade-offs meant that not every desire would 

be met, it allowed the programs to establish sound business cases for 

moving forward with new increments, and provided the warfighters with 

some assurance that the end product would be delivered quickly and 

perform as expected. This type of proactive approach allowed the legacy 

programs to begin fielding their first increments of modernized aircraft—in 

each case designated as C/D series aircraft—in less than 5 years from 

the start of their respective modernization programs. The following 

examples from the F-16 and F/A-18 programs provide further illustration:

• F-16 Fighting Falcon: The Air Force established an F-16 

Multinational Staged Improvement Program in February 1980. The 

program provided a structured means of incrementally modifying and 

upgrading the F-16, and was originally conceived with three stages. 

Although the specific content of each future stage was not fully 

defined at the outset, the program office worked closely with the 

warfighters, technology developers, and other program offices to 

establish feasible and affordable requirements as each successive 

stage approached. According to a RAND Corporation study8

 

8 RAND Corporation, The F-16 Multinational Staged Improvement Program: A Case Study 

of Risk Assessment and Risk Management, N-3619-AF (Santa Monica, Calif.: 1993).

done for 

the Air Force in 1993, “[the staged improvement program was] 

essentially a management device for coordinating many concurrent 

efforts to integrate subsystems with one another and an F-16 

airframe. That is, in each stage, new designs of the F-16 [were] 

conceived that integrate[d] many new subsystems to create a 

coherent aircraft with new combat capabilities.” As new subsystems 

with potential for future F-16 integration were developed, the F-16 
 

Page 11 GAO-12-524 F-22A Modernization Comparison

program office established a relationship with the subsystem program 

office, in some cases providing aircraft for testing and influencing 

design, to help mature the technology and facilitate future integration 

onto the F-16. In most cases, new technologies were incorporated 

onto new production aircraft on the production line. The first F-16C/D 

aircraft was delivered to the Air Force on schedule in December 1984, 

less than 5 years after the beginning of the improvement program.9

• F/A-18 Hornet: The first major upgrade of the F/A-18 began in 1984, 

with the issuance of an engineering change proposal. The Navy’s 

stated goal was to improve the F/A-18’s existing capabilities while 

also providing some new capabilities in the areas of avionics, 

armament, and electronic warfare.10

Although the programs began for different reasons, our analysis of 

program data provided to the Congress in selected acquisition reports in 

December of the year immediately preceding the start of each respective 

modernization program indicates that they began at essentially the same 

points in development and procurement. For example, we found that the 

F-16, F/A-18, and F-22A had all funded more than 85 percent of their 

projected development costs, funded less than one-third of their 

The upgrade was also expected 

to provide new mission computers with adequate speed, interface, 

and memory capacity to facilitate future growth. The Navy planned to 

use technologies, or subsystems, that had been developed and 

matured outside of the F/A-18 program. In its December 1985 

selected acquisition report to the Congress, the Navy noted that the 

new subsystems, or technologies, for the F/A-18 upgrade would be 

provided as government-furnished equipment. Therefore, the costs 

and risks associated with developing and maturing the technologies 

were not borne by the F/A-18 program. The program integrated the 

new technologies into its production line in 1986 and received the first 

F/A-18C/D aircraft as scheduled the following year—only 3 years after 

the engineering change proposal was first issued.

 

9 Although the F-16 modernization program began in February 1980, the first stage of the 

program simply focused on adding structural and wiring provisions to the baseline aircraft 

to support future upgrades. The aircraft receiving those upgrades were ultimately 

designated as Block 15 aircraft. The first major upgrade came in the second stage of 

modernization, leading to development and delivery of the first F-16C/D series aircraft, 

designated as a Block 25.

10 These capability upgrades were primarily expected to come from the addition of the 

Advanced Medium Range Air-to-Air Missile, Joint Tactical Information Distribution System, 

Flight Incident Recorder and Aircraft Monitoring System, and Advanced Self Protection 

Jammer. 
 

Page 12 GAO-12-524 F-22A Modernization Comparison

estimated procurement costs, and procured less than 20 percent of their 

total estimated aircraft quantities. The F-15 program was also nearly done 

with development when it started modernizing, but it was further along in 

procurement, having funded and procured more than 40 percent of its 

projected aircraft. Figure 1 compares and contrasts the specific 

percentages for each program, and to provide additional context, it 

identifies the total estimated costs—converted to 2012 dollars—and total 

procurement quantities from which the percentages were calculated.

Figure 1: Comparison of Investment Progress Prior to Modernization
 

Page 13 GAO-12-524 F-22A Modernization Comparison

All of the modernization programs also began around similar acquisition 

events. Our review of program selected acquisition reports and other 

program data found that all of the programs began modernizing after they 

had initiated production and around the time they achieved initial 

operating capability. It is important to note, however, that those 

acquisition events took place much later in the F-22A program, primarily 

because the original development program was over 14 years long, while 

the legacy development programs were 5 to 7 years long.

Nearly all F-22A modernization upgrades will have to be retrofitted onto 

fielded aircraft while the legacy programs integrated their upgrades into 

new production aircraft. The Air Force began integrating F-22A Increment 

2 onto production aircraft in 2007, and received the first Increment 2 

aircraft from the contractor the following year. All of the remaining aircraft 

were produced and delivered with Increment 2 upgrades incorporated. 

However, F-22A production was terminated in 2009, before the second 

modernization increment (Increment 3.1) had finished development, so 

the remaining modernization increments will have to be retrofitted into the 

fleet. As a result, the aircraft will have used up some of their service life 

by the time they are fully upgraded. Based on F-22A flight hour data 

provided by the program office our analysis indicates that a large number 

of aircraft are likely to have flown more than 1,500 hours, or nearly 20 

percent of their 8,000-hour service lives, before the Increment 3.2B 

upgrades are fielded.11

It should also be noted that retrofitting upgrades onto stealth aircraft with 

fully integrated computer systems—referred to as fused or integrated 

avionics—like the F-22A is a riskier and more complex process than 

integrating new technologies into a conventional aircraft with separate 

and distinct computer systems and software for each subsystem—known 

as federated avionics—even if the technologies are mature. In large part, 

this is because any changes made to the F-22A have to conform to the 

In contrast, the legacy programs produced entirely 

new upgraded aircraft.

 

11 We obtained actual flight hour data from the F-22A program office for January 2007 

through January 2012. We then calculated the average flight hours per year for each of 

those aircraft over that 5-year period, and used those averages to project the number of 

hours that each aircraft might fly from January 2012 through January 2018, around the 

time Increment 3.2B begins fielding. We then added those projected hours to the actual 

number of hours flown by each aircraft through January 2012. 

F-22A Upgrades Are Being 

Retrofitted onto Complex, 

Stealth Aircraft While 

Legacy Programs 

Incorporated Upgrades 

into Production of New, 

Less Complex Aircraft
 

Page 14 GAO-12-524 F-22A Modernization Comparison

aircraft’s overall stealth design and will require updates to the aircraft’s 

computer operating software. For example, the F-22A requires missiles 

that are carried and launched from internal weapons bays—not hung on 

the wings or under the fuselage as is the case with the F-16, F-15, and 

F/A-18. In addition, any new weapon added to the aircraft will also require 

new software to target and launch the weapon. For the F-22A, that 

software will have to be fully integrated into the aircraft’s overall avionics 

system and tested thoroughly to determine its impact on all of the 

aircraft’s other systems, which is costly and time consuming. Office of the 

Secretary of Defense officials point out that the legacy systems also had 

to integrate and test new software to ensure that it would work properly, 

but because the avionics systems were federated that process did not 

take as long and was less costly. In addition, the legacy aircraft had 

greater freedom to place new technologies onto the exterior of the aircraft 

or make structural changes as needed.

Given the stealth and avionics complexities of the F-22A, it is likely that it 

will be more costly to modernize than the F-15, F-16, or F/A-18. F-22A 

contractor officials emphasize that these complexities translate into labor 

hours and ultimately costs that the legacy programs would not have 

incurred. The total cost of F-22A modernization—through Increment 

3.2B—is currently estimated to be $9.7 billion. We were not able to isolate 

comparable costs for the legacy modernization programs, primarily 

because they all funded and managed modernization as a continuation of 

their initial baselines. As a result, their respective selected acquisition 

reports and budget requests did not explicitly identify all of their 

modernization costs or funding needs.12

As DOD pursues more complex and costly fighter aircraft to meet the 

advanced threats of the future, it is increasingly important that programs 

begin planning for incremental modernization at the earliest possible 

point. An overall incremental approach to development and early 

modernization planning were keys to the success of the legacy aircraft 

modernization programs we reviewed. From the beginning, they worked 

with the warfighters, technology developers, and in some cases foreign 

governments, to match requirements with available resources, and 

 

12 The F/A-18E/F and EA-18G programs are two exceptions. Both of these later F/A-18 

upgrades were essentially managed as new acquisition efforts, and thus had distinct cost 

and funding baselines, selected acquisition reports, and budget requests.

Concluding 

Observations
 

Page 15 GAO-12-524 F-22A Modernization Comparison

quickly developed and delivered new increments of upgraded aircraft to 

the warfighters. In most cases, the programs delivered initial increments 

of aircraft with limited capabilities, with the expectation that they would be 

upgraded over time as funding and technologies became available. 

Although the legacy and F-22A programs began modernizing at the same 

general points in time, the F-22A did not originally plan for a major 

modernization program, so when the aircraft’s mission changed in 2003, 

the resources—primarily technology and funding—needed to meet the 

new requirements had not been fully developed or identified. As a result, 

the cost, schedule, and performance projections for the F-22A 

modernization program were not well founded and, over time, costs have 

doubled and the delivery of the full required capability has been delayed 

by more than 7 years. In addition, the majority of the F-22A modernization 

upgrades will be retrofitted onto fielded aircraft—a complex and costly 

undertaking—and by the time all of the required capabilities are fielded 

the amount of useful life remaining on the aircraft will likely be limited.

DOD reviewed a draft of this report and had no formal written comments. 

However, DOD did provide technical comments that were incorporated as 

appropriate.

We are sending copies of this report to the Secretary of Defense, the 

Secretary of the Air Force, the Secretary of the Navy, the Commandant of 

the Marine Corps, the Director, Office of Management and Budget, and 

interested Congressional Committees. In addition, the report is available 

at no charge on the GAO website at http://www.gao.gov. 

If you or your staff have any questions about this report, please contact 

me at (202) 512-4841 or sullivanm@gao.gov. Contact points for our 

Offices of Congressional Relations and Public Affairs may be found on 

Agency Comments 
 

Page 16 GAO-12-524 F-22A Modernization Comparison

the last page of this report. GAO staff who made key contributions to this 

report are listed in appendix III. 

Michael J. Sullivan, Director

Acquisition and Source Management
Appendix I: Scope and Methodology

Page 17 GAO-12-524 F-22A Modernization Comparison

In order to compare and contrast the F-22A modernization program with 

those of the F-15, F-16, and F/A-18, we examined key program 

requirements and acquisition documents and prior GAO work. In addition, 

we interviewed knowledgeable Office of the Secretary of Defense (OSD), 

Air Force, Navy, and contractor officials, as well as former program 

officials. We also reviewed relevant studies done by the RAND 

Corporation and discussed those studies with knowledgeable RAND 

Corporation officials. We obtained documents, data, and other information 

from officials at the Aeronautical Systems Center, Wright-Patterson Air 

Force Base, Ohio; Air Combat Command, Langley Air Force Base, 

Virginia; Naval Air Systems Command, Naval Air Station Patuxent River, 

Maryland; and Lockheed Martin Corporation. We were also asked to 

review the F-117A program, and while we were able to discuss the 

program with some former contractor and program officials, we were not 

able to collect sufficient information relevant to the objectives of this 

report. The officials we met with noted that most of the primary source 

documentation related to the original program is either still highly 

classified or difficult to access because of the amount of time that has 

passed.

In conducting our analysis, we identified relevant cost, schedule, and 

requirements information from selected acquisition reports, budget 

documents, program briefings, and official service histories. To ensure 

that our comparisons reflected programs at common points in 

development and procurement, we first summarized and compared the 

data for each program at 5-, 10-, 15-, and 20-year intervals following the 

start of the initial development program. We then used the start of 

modernization as our common point and identified and compared the 

cost, schedule, and quantity status of each program—in percentage 

terms to normalize the data—based on data in the selected acquisition 

reports provided to the Congress in December of the year preceding the 

start of modernization. According to the service officials we spoke with, 

modernization is generally a process whereby upgrades and 

modifications are made in response to new requirements and to capitalize 

on advances in technology to increase an aircraft’s capabilities over time.

To estimate the likely number of flights hours that F-22A aircraft will have 

flown before Increment 3.2B is fielded, we obtained actual flight hour data 

from the F-22A program office for January 2007 through January 2012. 

We then calculated the average flight hours per year for each of those 

aircraft over that 5-year period, and used those averages to project the 

number of hours that each aircraft might fly from January 2012 through 

January 2018, around the time Increment 3.2B begins fielding. We then 

Appendix I: Scope and Methodology
Appendix I: Scope and Methodology

Page 18 GAO-12-524 F-22A Modernization Comparison

added those projected hours to the actual number of hours flown by each 

aircraft through January 2012.

To assess the reliability of the program cost, funding, schedule, quantity, 

and flight hour data we used, we talked to agency officials about the 

processes and practices used to generate the data. We also corroborated 

the data by reviewing relevant documentation from various sources. We 

determined that the data were sufficiently reliable for the purposes of this 

report.

We conducted this performance audit from June 2011 to April 2012 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: System Modernization Summaries

Page 19 GAO-12-524 F-22A Modernization Comparison

This appendix provides more details on the modernization programs of 

the fighter and attack aircraft addressed in the body of this report. Each 

system summary includes a general overview of the modernization 

program and a more detailed discussion of key aspects of each 

modernization increment. Each program summary also includes a 

modernization timeline. The timelines depict the length of the original 

development program and illustrate the amount of time between the start 

of development—represented by year 0—and other key program events, 

including initial operating capability (IOC), the beginning of modernization, 

and the delivery of new upgraded capabilities. The F-22A timeline depicts 

the total estimated time frame for retrofitting the fleet with full global strike 

capability, from Increment 2 through Increment 3.2B, and the timelines for 

the F-15, F-16, and F/A-18 depict the time frames for the fielding of each 

new increment (series) of aircraft.

Appendix II: System Modernization 

Summaries 
Appendix II: System Modernization Summaries

Page 20 GAO-12-524 F-22A Modernization Comparison

Figure 2: F-22A Raptor

Development start: June 1991

Initial operating capability: December 2005

Development cycle time: 14 years

Production cycle time: 11 years

Total aircraft procured: 179

In 2003, the Air Force established the F-22A modernization program in 

response to requirements for robust air-to-ground and other new 

capabilities. Around that same time, the Air Force also initiated efforts to 

improve the reliability and maintainability of the aircraft, although those 

efforts are not officially part of the modernization program. The new 

requirements represented a significant change from the F-22A’s original 

air superiority mission. Initial development work on modernization 

enhancements started in 2003 and was initially planned to extend over a 

Program Modernization 

Overview
Appendix II: System Modernization Summaries 

Page 21 GAO-12-524 F-22A Modernization Comparison

7-year period with fielding of the full increment of required capabilities 

expected to start by 2010 and cost more than $4 billion. However, the 

program has since been restructured—largely because of requirements 

changes and funding instability according to program officials. Program 

officials are not sure when the full required capability will be delivered, 

and the total amount invested from 2003 through 2023 is currently 

estimated to be $9.7 billion.

The Air Force plans to achieve the full increment of air-to-ground attack 

capability by developing portions of that capability and retrofitting them 

into its F-22A fleet in several phases. The first phase—known as 

Increment 2—has been fielded. The second phase—known as Increment 

3.1—has completed operational testing and is now being retrofitted onto 

the aircraft. The Air Force expects to issue the final operational test and 

evaluation report for Increment 3.1 in 2012. The third phase—known as 

Increment 3.2—has been divided into two smaller phases referred to as 

Increments 3.2A and 3.2B. Increment 3.2A is almost exclusively software 

focused and is currently in development. The Air Force will manage 

Increment 3.2B as a separate major defense acquisition program and 

recently received approval from OSD to begin preparation for a Milestone 

B review in the first quarter of fiscal year 2013. Figure 3 provides a 

timeline of F-22A modernization highlighting key events such as the start 

of the original aircraft development program, the beginning of production, 

the achievement of IOC, the start of the modernization program, and the 

overall time frame for fully fielding new global strike capabilities from the 

beginning of Increment 2 retrofits through the planned completion of 

Increment 3.2B retrofits. 

Figure 3: F-22A Modernization Timeline
Appendix II: System Modernization Summaries

Page 22 GAO-12-524 F-22A Modernization Comparison

The Air Force began production of the F-22A before all of the basic 

program requirements had been met. As a result, it was forced to begin a 

modernization program to fully mature and retrofit technologies onto 

aircraft that had already been delivered to the war fighter. The Air Force 

began F-22A modernization in 2003 with Increment 2, which was the first 

of four phases needed to achieve the full required capability. This phase 

was expected to fix problems left over from the original development 

program and provide some basic air-to-ground attack capabilities. Many 

of the upgrades in this phase were software related, although the 

incorporation of the Joint Direct Attack Munition for basic air-to-ground 

missions was also included.

Follow-on operational testing and evaluation for F-22A fighters 

incorporating Increment 2 capabilities, including assessments of 

expanded air-to-ground mission capability and improvements in system 

suitability, were successfully completed in August 2007. The related 

upgrades were subsequently incorporated into the F-22A production line. 

Aircraft configured with Increment 2 capabilities were found to be 

operationally effective in suppressing and destroying fixed enemy air 

defenses, and also demonstrated fixes of some deficiencies and weapons 

integration problems that had been significant detractors in the original 

test program. Aircraft demonstrated the ability to employ the Joint Direct 

Attack Munition at supersonic speeds in a high-threat anti-access 

environment where stealth capabilities are needed. In comparison, the 

baseline aircraft (pre-Increment 2) were only capable of launching the 

Joint Direct Attack Munition at fixed targets in lower-threat environments 

and at slower speeds.

Increment 3.1 is now being fielded and adds enhanced air-to-ground 

attack and enhanced radar capabilities. These capabilities are expected 

to further enhance the F-22A’s air-to-ground capability by allowing the 

aircraft to find and target ground targets with on-board systems, rather 

than relying on external personnel and platforms for targeting. Increment 

3.1 began development in December 2006. The Air Force began 

retrofitting aircraft with Increment 3.1 capabilities in 2011 and expects to 

continue retrofitting through 2016.

The Air Force began Increment 3.1 operational testing in January 2011 

but soon encountered flight delays—because of the grounding of the 

fleet—that persisted from May to September 2011. However, the Air 

Force was able to complete flight testing for Increment 3.1 in November 

Increment 2

Increment 3.1
Appendix II: System Modernization Summaries

Page 23 GAO-12-524 F-22A Modernization Comparison

2011 and now expects to release the operational test report in late March 

2012.

Increment 3.2 has been broken into two phases, referred to as 

Increments 3.2A and 3.2B, and is expected to deliver additional advanced 

global strike capabilities. The Air Force initially expected this phase to 

deliver the final installment of capabilities that would meet the full air-toground requirements. The related capabilities include enhanced 

weapons, improved communications, and self-protection upgrades. The 

program office originally expected to begin fielding these capabilities in 

2010, but according to program officials, requirements and funding 

instability have caused the program schedule to slip by more than 7 

years, and they do not currently known when the full capability will be 

achieved.

Increment 3.2A development began in November 2011 and is expected to 

update existing software to enhance Electronic Protection and Combat 

Identification capabilities. The first developmental test events for this 

increment are expected to start in late 2012 and be completed in late 

2013. Operational testing is planned to conclude in early 2014 with 

fielding of Increment 3.2A planned to occur between 2014 and 2016.

In December 2011, the Air Force received approval from OSD to begin 

the process of structuring Increment 3.2B as a new major defense 

acquisition program. The formal start of system development—Milestone 

B—on Increment 3.2B is planned for the first quarter of fiscal year 2013, 

with fielding to take place between 2017 and 2020. Key efforts in 

Increment 3.2B include integration of the AIM-9X and AIM-120D missiles 

and upgrading Geolocation and Electronic Protection subsystems.

Increment 3.2
Appendix II: System Modernization Summaries

Page 24 GAO-12-524 F-22A Modernization Comparison

Figure 4: F-15 Eagle/Strike Eagle

Development start: January 1970

Initial operating capability: September 1975

Development cycle time: 5 years

Production cycle time: 30 years

Total aircraft procured: 1,074

For more than three decades, the Air Force has focused on upgrading 

and modifying the F-15 by defining, developing, and producing 

increments of militarily useful capabilities. The primary drivers behind 

F-15 modernization included basic capability improvements as well as the 

need to address capability gaps and respond to evolving threats. Since 

the beginning of the original development program in 1970, there have 

been two major F-15 upgrades: one that resulted in the production of the 

F-15C/D series aircraft and another more extensive upgrade that resulted 

Program Modernization 

Overview
Appendix II: System Modernization Summaries

Page 25 GAO-12-524 F-22A Modernization Comparison

in the production of the F-15E multimission aircraft series. Figure 5 

provides a timeline of F-15 modernization highlighting several key 

program events, such as the start of the original aircraft development 

program, the beginning of production, the achievement of IOC, and the 

start of each major modernization upgrade. The figure also indicates 

when the first upgraded F-15C/D and F-15E were delivered to the Air 

Force.

Figure 5: F-15 Modernization Timeline

The Air Force began the F-15 program with the intent to quickly develop 

and acquire a weapon system capable of operating as an advanced, 

high-performance, air superiority fighter. The Air Force made several 

other changes to the F-15 platform to reduce costs and bring the program 

within funding constraints while still retaining an acceptable level of 

capability. In one instance, officials decided to reduce the size of the 

F-15’s internal fuel tanks to reduce cost, which subsequently resulted in a 

reduction in the aircraft’s mission radius. Officials believed that a reduced 

internal fuel capacity would still provide them with an acceptable mission 

radius, along with the added benefit of reducing the size, weight, and cost 

of the aircraft. Several changes were also made to the F-15’s avionics 

systems to make the aircraft more affordable. Although the F-15 program 

ended up being costly relative to other programs at the time, the Air Force 

was able to begin delivering initial increments of operational aircraft within 

5 years.

Although the F-15 was able to develop and deliver an initial operating 

capability of its baseline aircraft (F-15A/B) just 5 years after development, 
Appendix II: System Modernization Summaries

Page 26 GAO-12-524 F-22A Modernization Comparison

as well as quickly deliver new increments of F-15C/D and F-15E aircraft, 

the overall program was not without difficulties. For example, in the early 

years the F-15A/B program had problems with its engines as well as 

performance problems with its tactical electronic warfare system. 

Additionally, the F-15C/D experienced problems with malfunctioning 

landing gear and the F-15E had difficulties with electronic warfare 

software development.

The transition from F-15A/B1

The Air Force recognized that the F-15 upgrade, which was designated 

Production Eagle Package-2000 (PEP-2000), was going to require 

significant modifications to the aircraft’s airframe. The primary focus of 

PEP-2000 was to increase the aircraft’s internal fuel capacity by 2,000 

pounds, thereby increasing mission radius. The upgrade was authorized 

in October 1976 and development began in January 1977, just 16 months 

after the first F-15 squadron achieved initial operating capability. In 

addition to adding 2,000 pounds of fuel, the PEP-2000 program was also 

focused on incorporating 8,000 pounds of additional equipment, such as 

provisions for carrying exterior conformal fuel pallets, and improved 

landing gear. The F-15A with PEP-2000 would become the F-15C, and 

to F-15C/D represented the first significant 

F-15 modernization effort. By the mid 1970s the Air Force had determined 

that the baseline F-15 needed to be upgraded, largely to increase the 

aircraft’s mission radius, which had been reduced earlier in the program 

to achieve cost savings. This first major F-15 upgrade was managed and 

funded as a continuation of the baseline F-15 program. As such, 

management and investment decisions were primarily made at the 

service and program levels and did not go through the higher-level—

OSD—review and approval process. The Air Force did not develop or 

produce any detailed mission needs statement or requirements 

documentation specifically for the upgrade program. No distinct cost or 

schedule baselines were developed, funding was requested and provided 

through the F-15 baseline budget, and program progress was reported to 

the Congress through the existing F-15 selected acquisition reports. The 

Air Force’s approach to upgrading the F-15 focused on incorporating new 

technologies into a modified variant of the basic F-15 airframe.

 

1 The primary distinction between F-15As and F-15Bs is that A-series aircraft have a 

single seat cockpit while the B-series aircraft have a dual-seat cockpit and are used for 

training. The same distinction exists between F-15C and F-15D.

F-15C/D
Appendix II: System Modernization Summaries

Page 27 GAO-12-524 F-22A Modernization Comparison

the F-15B with PEP-2000 would become the F-15D. The first F-15C was 

delivered to the Air Force in May 1979, just a little over 2 years after the 

PEP-2000 program began.

In 1982, the Air Force began to evaluate the need for a multirole (air-to-air 

and air-to-ground) fighter capable of operating at night and in adverse 

weather conditions. The Air Force received competitive demonstrations of 

advanced versions of the F-15 and F-16—designated the F-15E and 

F-16XL—from the respective aircraft contractors and on February 24, 

1984, chose the F-15E to meet the dual-role fighter requirement. At the 

time the Air Force selected the F-15E to meet its multirole fighter 

requirement, the baseline F-15 had been operational for over 8 years and 

the F-15 program had produced 834 total aircraft.

The F-15E was designed to provide a long-range, large-payload 

capability to strike second echelon targets at night and in adverse 

weather while retaining superior air defense capability. Additionally, the 

F-15E, which was originally designed as a derivative of the F-15D twoseater, would support two crew members. While the F-15E was treated 

as a new aircraft build, it was managed and funded as a continuation of 

the baseline F-15 program, similar to the PEP-2000 upgrade. However, 

the F-15E was developed and procured under a new contract that 

required competition, while the PEP-2000 upgrade was developed and 

procured as a program management directive that required no 

competition and no new contract. Much like earlier F-15 models, the 

F-15E program was committed to using existing technologies as much as 

possible and chose to build on a mature and proven airframe, the 

F-15C/D. The Air Force received its first F-15E in March 1987, and the 

new aircraft achieved limited initial operating capability in September 

1989.2

 

2 The F-15E achieved a limited initial operating capability on September 30, 1989. The 

limited operational capability resulted from the lack of certain features, including automatic 

terrain following, the Low Altitude Navigation and Targeting Infrared for Night pod, a new 

ammunition feed system, and in part from delayed installation of the electronic 

countermeasures system. 

F-15E
Appendix II: System Modernization Summaries 

Page 28 GAO-12-524 F-22A Modernization Comparison

Figure 6: F-16 Fighting Falcon

Development Start: April 1975

Initial Operating Capability: October 1980

Development Cycle Time: 5.5 years

Production Cycle Time: 28 years

Total Aircraft Procured: 2,231

The Air Force has modernized the F-16 over the past three decades by 

making incremental upgrades and modifications to a baseline aircraft. 

Over that time span, the Air Force has developed and fielded two major 

Program Modernization 

Overview
Appendix II: System Modernization Summaries

Page 29 GAO-12-524 F-22A Modernization Comparison

F-16 increments, or aircraft series, the F-16A/B and the F-16C/D.3

In February 1980, several months before the baseline aircraft achieved 

initial operating capability, the Air Force established the Multinational 

Staged Improvement Program (MSIP) for the F-16, primarily to provide a 

structured means of incrementally modifying and upgrading the aircraft 

over time. The program was originally conceived with three stages, 

although the detailed content of each stage was not fully defined. Figure 7 

provides a timeline of F-16 modernization highlighting key events, such 

as the start of the original aircraft development program, the beginning of 

production, the achievement of initial operating capability, and the start of 

the overall modernization program. The figure also indicates when the 

first upgraded F-16C/D was delivered to the Air Force and notes the start 

of each block upgrade.

Within 

those major increments several subgroups, or blocks of aircraft with 

common capabilities, have also been developed and produced. The first 

three blocks, Blocks 5, 10, and 15, were all F-16A/B series aircraft, while 

the last four blocks, Blocks 25, 30/32, 40/42, and 50/52, were all F-16C/D 

series aircraft.

 

3 The A and B series aircraft are essentially identical with the exception of the number of 

seats in the cockpit. The A series aircraft have one seat while the B series aircraft have 

two. This same distinction exists for the C and D series aircraft as well. Given this high 

degree of commonality, each series pairing is typically referred to as a single unified 

increment, like A/B and C/D and not four distinct increments.
Appendix II: System Modernization Summaries

Page 30 GAO-12-524 F-22A Modernization Comparison

Figure 7: F-16 Modernization Timeline

The Air Force’s approach to the original F-16 development program 

provides insight into some of the basic management principles and 

practices that have continued to guide the aircraft’s evolution. Those 

principles and practices have focused on ensuring affordability and 

technical feasibility before making large investments. This has required a 

consistent willingness on the part of decision makers and warfighters to 

accept incremental capability improvements and resist the pressure to 

attempt to make large capability leaps in a single step. This simplified, 

limited-capability approach has been evident from the beginning of F-16 

development. When full-scale development of the F-16 began in April 

1975, the Air Force had not documented any official requirements for the 

aircraft. Instead, the Air Force chose to use a concept paper issued in 

January 1973 to guide a fighter prototype program, known as the 

Lightweight Fighter Prototype Program. According to the concept paper, 

“The [lightweight fighter] prototype [was] expected to demonstrate in 

hardware the technology leading to a relatively low cost, high thrust-toweight ratio in advance of stated operational requirements.” Given this 

early development work, and despite concerns about high levels of 

concurrency between development and production, the Air Force initiated 

F-16 production less than 2 years after the start of full-scale development 

and achieved initial operating capability in 1980, only 5 years after the 

start of development.
Appendix II: System Modernization Summaries

Page 31 GAO-12-524 F-22A Modernization Comparison

While the F-16 was able to quickly develop and deliver differing versions 

of the aircraft to the warfighter over time, it was not without some 

difficulty. For example, the F-16A/B had problems with its radar that 

required additional development and testing. The F-16C/D also 

experienced radar problems stemming from marginal performance and 

inaccurate readings.

The Air Force started F-16 modernization very early in the aircraft’s life 

cycle, formally starting MSIP Stage I in February 1980. MSIP was funded 

and managed as a continuation of the original F-16 development 

program. This first stage primarily focused on making structural, wiring, 

interface, and cooling modifications, and resulted in the production of 

F-16A/B Block 15 aircraft. The modifications were relatively minor and did 

not require much new design or development work. However, the Air 

Force believed these modifications were essential to support future 

upgrades and preclude the need for costly modifications and retrofits. 

Also, as part of Stage I, the Air Force increased the size of the aircraft’s 

vertical tail to address performance issues identified during flight testing. 

The aircraft contractor delivered the first Block 15 aircraft in November 

1981, less than 2 years after Stage I began.

The Air Force worked closely with the aircraft contractor to identify and 

agree to the specific modifications that would be made as part of Stage I. 

Once agreement was reached, the Air Force and contractor had agreed 

to a number of structural, wiring, and interface modifications. However, 

the modifications required little new design or development work, so the 

Air Force was able to incorporate the changes directly onto the F-16 

production line and quickly integrate them into production aircraft. In total, 

the Air Force expected to incorporate Stage I modifications into 455 

production aircraft starting in November 1981. The RAND Corporation 

reported in 1993 that “because little design work was required, 

developers viewed this stage as presenting little technical risk; rather, the 

main risk was associated with [Stage I] was whether provision made for 

future systems were the right ones. If future needs differed from those 

anticipated during Stage I, rework would be required to retrofit future 

systems.”

The beginning of MSIP Stage II, which started 15 months after the 

beginning of Stage I, was officially authorized by the F-16 Joint 

Multinational Configuration Control Board in May 1981. Many of the Stage 

II modifications built on the provisions made during Stage I and focused 

Stage I: F-16A/B Block 15

Stage II: F-16C/D Blocks 25 

and 30/32
Appendix II: System Modernization Summaries

Page 32 GAO-12-524 F-22A Modernization Comparison

on further increasing the aircraft’s capacity to accommodate additional 

upgrades. One RAND Corporation official we met with told us that at one 

point early in the F-16 program the aircraft was “gaining a pound a day” 

because of the number of requirements changes and related 

modifications that were being made. Stage II modifications were much 

more extensive than those in Stage I. The Stage II modifications included 

the incorporation of a new fire-control radar, additional electrical power 

and cooling capacity, additional computer memory, provisions for the 

Advanced Medium Range Air-to-Air Missile, and an alternate aircraft 

engine. The Air Force not only assigned Stage II aircraft unique block 

numbers—beginning with Block 25 and eventually moving to Block 

30/32—but it also changed the aircraft series designation from F-16A/B to 

F-16C/D. The aircraft contractor delivered the first F-16C/D, a Block 25 

aircraft, in December 1984, less than 4 years after Stage II began.

The Air Force’s approach to MSIP Stage II was not significantly different 

from its approach to Stage I—that is, an incremental, but highly 

concurrent approach. Most of the modifications and upgrades planned for 

Stage II were based on variants of subsystems and technologies that 

were already in use on other fighter aircraft, bomber aircraft, or both. 

According to the RAND Corporation’s detailed review of MSIP, the MSIP 

managers viewed the risk associated with this stage as low to moderate 

because of the stage’s evolutionary nature. They pointed out that as new 

capabilities became available—that is, as technologies matured—the Air 

Force would begin to plan for the integration of those capabilities into the 

F-16 production line. Similar to the first MSIP stage, nearly all of the 

modifications and upgrades for Stage II were ultimately worked into the 

F-16 production line, with some limited retrofitting of fielded aircraft. The 

Air Force was able to work the changes into the production line largely 

because production of F-16A/B aircraft had continued during the early 

phases of Stage II. This highly concurrent environment continued. While 

the Block 25 aircraft were in production, the MSIP officials continued to 

explore additional possible modifications and ultimately made changes 

that resulted in another aircraft configuration, designated the Block 30/32. 

Between Blocks 25 and 30/32 the Air Force added new weapon 

capabilities and incorporated an alternate fighter engine.

4

 

4 The difference between the Block 30 and Block 32 aircraft is simply which fighter engine 

the aircraft have. The Air Force carried this same distinction forward into the Block 40/42 

and 50/52 aircraft as well.
Appendix II: System Modernization Summaries

Page 33 GAO-12-524 F-22A Modernization Comparison

The Air Force received approval to start MSIP Stage III in June 1985. 

This stage introduced further advances in the F-16 fire-control radar and 

computer capacity, in addition to introducing night vision infrared 

navigation and targeting, global positioning system, and High-speed 

Antiradiation Missiles (HARM), among other changes in weapon, radar, 

and avionics systems. Stage III ultimately resulted in two new F-16C/D 

block configurations—Block 40/42 and Block 50/52—each with its own 

distinct mission focus. According to the RAND Corporation, the Air 

Force’s approach was a “development-and-integration approach” that 

was marked by “the continual introduction of pre-planned changes and 

updates.” During Stage III, the Air Force continued to monitor the 

technology market and work closely with technology developers to mature 

and integrate new capabilities into the aircraft while concurrently 

producing and fielding of Block 30/32 aircraft.

The key focus of the Block 40/42 modifications was the incorporation of 

nighttime flying and targeting capability, primarily provided by the Low 

Altitude Navigation and Targeting Infrared for Night (LANTIRN) system, to 

support precision strike missions, which had been deferred from the Block 

25 program. In contrast, the Block 50/52 modifications focused on fully 

integrating the HARM targeting system to provide the capability to 

suppress enemy air defenses. While the development programs for both 

LANTIRN and HARM were managed and funded as distinct acquisition 

efforts, the F-16 program office provided aircraft for flight testing. This 

collaborative approach, which had also been used during previous MSIP 

stages, allowed the technology programs to mature while also allowing 

the F-16 program to address integration and performance problems 

before investing in significant modifications. The Air Force procured a 

combined total of 913 Block 40/42 and 50/52 aircraft between fiscal years 

1987 and 2001. The first Block 40/42 aircraft was funded for procurement 

in fiscal year 1987 and delivered to the Air Force in December 1988—less 

than 4 years after Stage III began. The first Block 50/52 was funded for 

procurement in fiscal year 1990 and delivered to the Air Force in October 

1991, over 6 years after Stage III began.

Stage III: F-16C/D Blocks 

40/42 and 50/52
Appendix II: System Modernization Summaries

Page 34 GAO-12-524 F-22A Modernization Comparison

Figure 8: F/A-18 Hornet/Super Hornet/Growler

Development start: December 1975

Initial operating capability: March 1983

Development cycle time: 7 years

Production cycle time: > 35 years

Total aircraft procured: 1,685

The Navy has taken an evolutionary approach to modernizing its F/A-18 

aircraft through incremental upgrades and modifications. The Navy has 

focused on upgrading and modifying the F/A-18 by defining, developing, 

and producing increments of militarily useful capabilities—both improving 

existing capabilities and adding new capabilities. Since the beginning of 

the original development program in 1975, there have been three major 

F/A-18 upgrades that produced the F/A-18C/D; the F/A-18E/F, 

designated the Super Hornet; and the EA-18G, designated the Growler. 

Figure 9 provides a the timeline of F/A-18 modernization highlighting key 

Program Modernization

Overview
Appendix II: System Modernization Summaries 

Page 35 GAO-12-524 F-22A Modernization Comparison

events, such as the start of the original aircraft development program, the 

beginning of production, the achievement of initial operating capability, 

and the start of each major modernization upgrade. The figure also 

indicates when the first upgraded F/A-18C/D and F/A-18E/F aircraft were 

delivered to the Navy.

Figure 9: F/A-18 Modernization Timeline

F/A-18 modernization has been driven by a combination of factors, 

including the need for regular capability improvements, the need to 

replace aging legacy aircraft to ensure that adequate force structure is 

maintained, and the need to respond to evolving threats and capability 

gaps with new available technologies. Program officials note that Navy 

has taken a basic evolutionary approach to modernizing the F/A-18. 

While the ultimate required capabilities—that is, the E/F or G series 

capabilities—had not been fully defined when the C/D series upgrades 

began, the engineering change proposal that guided the C/D series 

upgrade fully defined the requirements for that increment of capability.

The Navy initiated the first major F/A-18 upgrade relatively early in the 

program’s life cycle with the issuance of an engineering change proposal 

in August 1984. At the time, the Navy had finished development of the 

F/A-18C/D
Appendix II: System Modernization Summaries

Page 36 GAO-12-524 F-22A Modernization Comparison

F/A-18A/B5 and was in the early stages of producing and fielding 

operational aircraft. The upgrade began just over 1 year after the first 

F/A-18 squadron achieved initial operating capability, just over 3 years 

after production started, and less than 9 years after the start of full-scale 

development. The decision to upgrade the F/A-18A/B was largely driven 

by the Navy’s desire to keep the aircraft’s capabilities current by taking 

advantage of newer and more advanced technologies. The Navy’s 

primary goal in issuing the engineering change proposal was to improve 

existing capabilities and provide some new capabilities in the areas of 

avionics, armament, and electronic warfare.6

The Navy managed and funded this first major F/A-18 upgrade as a 

continuation of the baseline program. As such, management and 

investment decisions were not required to go through higher-level DOD 

reviews, but were instead made at the service level by Navy leadership. 

The Navy did not develop or produce any detailed mission needs 

statement or requirements documentation to support the upgrade. No 

distinct cost or schedule baselines were developed, funding was 

requested and provided through the F/A-18 baseline budget, and program 

In addition, the upgrade was 

expected to provide new mission computers with adequate speed, 

interface, and memory capacity to facilitate future growth. The Navy 

planned to use technologies, or subsystems, that had been developed 

and matured outside of the F/A-18 program. The program’s December 

1985 selected acquisition report noted that the technologies were 

expected to be provided to the program as government-furnished 

equipment. The engineering change proposal noted that the modifications 

would be made to aircraft on the production line, beginning with the 

aircraft planned for procurement in fiscal year 1986. The first F/A-18C/D 

aircraft was delivered to the Navy in October 1987, a little more than 3 

years after modernization began. The Navy procured a total of 627 

F/A-18C/D aircraft over a nearly 13-year period, with the final aircraft 

being delivered in August 2000.

 

5 The primary distinction between F/A-18As and F/A-18Bs is that A-series aircraft have a 

single-seat cockpit while the B-series aircraft have a dual-seat cockpit. The same 

distinction exists between F/A-18C and F/A-18D, as well as the F/A-18E and F/A-18F 

series aircraft. 

6 These capability upgrades were primarily expected to come from the addition of the 

Advanced Medium Range Air-to-Air Missile, Joint Tactical Information Distribution System, 

Flight Incident Recorder and Aircraft Monitoring System, and Advanced Self Protection 

Jammer. 
Appendix II: System Modernization Summaries

Page 37 GAO-12-524 F-22A Modernization Comparison

progress was reported to the Congress through the existing F/A-18 

selected acquisition reports. Program officials note that the Navy’s 

approach emphasized use of mature technologies and the integration of 

those technologies onto F/A-18 airframes that were already in production. 

They point out that with the exception of some minor modifications, the 

upgrade did not require any structural changes to the existing F/A-18 

airframe.

In May 1992, the Navy sought and received OSD approval to begin fullscale development of its second major F/A-18 upgrade, designated the 

F/A-18E/F Super Hornet.7

Unlike the first major upgrade, which was funded and managed as a 

continuation of the baseline program, the F/A-18E/F upgrade was 

approached as a new formal acquisition program. Although the Navy 

considered the F/A-18E/F development a modification—in its estimation, 

it was a logical continuation of the general F/A-18 upgrade strategy—the 

program was funded and managed as a new acquisition program within 

the framework of DOD’s acquisition policies. The F/A-18E/F program was 

committed to using existing technologies as much as possible and chose 

to build on a mature and proven aircraft, the F/A-18C/D. The Navy 

received its first production F/A-18E in December 1998, less than 7 years 

after development began, and achieved initial operating capability in 

September 2001. As of December 2010, the Navy expected to procure a 

At the time, the F/A-18 aircraft had been 

operational for nearly 10 years. The decision to develop the F/A-18E/F 

was based on the Navy’s determination that it needed an upgraded 

carrier-based, multi-role fighter to ensure that it had enough operational 

aircraft to adequately man its aircraft carriers in the 1990s and early 

2000s. The Navy expected the upgrade to address shortfalls in the 

F/A-18’s range and ability to return to the carrier with unused weapons 

and stores (referred to as carrier recovery payload). In addition, the 

upgraded aircraft were expected to be stealthier and thus more survivable 

than the F/A-18A-D aircraft they would replace.

 

7 In January 1988, more than 4 years before beginning full-scale development of the 

F/A-18E/F, the Navy and the aircraft contractor began to study concepts for a more 

advanced variant of the F/A-18, which was referred to as Hornet 2000. At the same time, 

the Navy awarded a fixed-price development contract for the A-12 stealth aircraft, which 

subsequently encountered significant cost and schedule problems, and was ultimately 

terminated by the Secretary of Defense in 1991. 

F/A-18E/F
Appendix II: System Modernization Summaries

Page 38 GAO-12-524 F-22A Modernization Comparison

total of 556 F/A-18E/F aircraft, with the final procurement projected to 

occur in fiscal year 2014.

The most recent variant of the F/A-18 aircraft is the EA-18G Growler, 

which is an electronic warfare-equipped F/A-18F. An analysis of 

alternatives was conducted to identify platforms that would be dedicated 

to providing advanced jamming capabilities for the suppression of enemy 

air defenses. The analysis was driven by a projected shortfall in the 

electronic attack inventory primarily caused by attrition and the increasing 

cost of operating the current aging fleet of EA-6B Prowlers. Based on the 

analysis of alternatives, the Navy chose to modify an F/A-18F instead of 

building an entirely new aircraft. OSD approved the start of EA-18G 

development in December 2003.

The Navy has managed the EA-18G program as a distinct major 

acquisition effort from the beginning. In fact, F/A-18 program officials 

emphasize that the EA-18G did not evolve from any F/A-18 

modernization or preplanned improvement program, but instead was 

selected from an analysis of alternatives to replace critical airborne 

electronic attack capabilities. They also emphasize that the EA-18G has 

distinctly different mission—electronic warfare—and therefore, while it is a 

variant of the F/A-18F, it is not viewed as a new increment.

At the time the EA-18G development program started, the Navy still had a 

significant amount F/A-18E/F procurement remaining with approximately 

370 aircraft still to be purchased, although it had already achieved initial 

operating capability. As a result, EA-18G development and procurement 

ended up being highly concurrent with F/A-18E/F procurement. The Navy 

received approval to begin EA-18G production in July 2007 and the 

aircraft achieved initial operating capability in September 2009. As of 

December 2010, the Navy anticipates procuring a total of 114 EA-18G 

aircraft, with the final procurement being made in fiscal year 2013.

EA-18G
Appendix III: GAO Contact and Staff 

Acknowledgments

Page 39 GAO-12-524 F-22A Modernization Comparison

Michael J. Sullivan, (202) 512-4841 or sullivanm@gao.gov

In addition to the contact named above, Bruce Fairbairn, Assistant 

Director; Travis Masters; Robert Miller; Marie Ahearn; Marvin Bonner; 

Laura Greifner; and Roxanna Sun made key contributions to the report.

Appendix III: GAO Contact and Staff 

Acknowledgments 

GAO Contact

Staff 

Acknowledgments
Related GAO Products

Page 40 GAO-12-524 F-22A Modernization Comparison

Defense Acquisitions: Assessments of Selected Weapon Programs. 

GAO-11-233SP. Washington, D.C.: March 29, 2011.

Tactical Aircraft: DOD’s Ability to Meet Future Requirements Is Uncertain, 

with Key Analyses Needed to Inform Upcoming Investment Decisions. 

GAO-10-789. Washington, D.C.: July 29, 2010.

Tactical Aircraft: DOD Need a Joint and Integrated Investment Strategy. 

GAO-07-415. Washington, D.C.: April 2, 2007.

Tactical Aircraft: DOD Should Present a New F-22A Business Case 

before Making Further Investments. GAO-06-455R. (Washington, D.C.: 

June 20, 2006).

Tactical Aircraft: Air Force Still Needs Business Case to Support F/A-22 

Quantities and Increased Capabilities. GAO-05-304. Washington, D.C.:

March 15, 2005.

Best Practices: Better Acquisition Outcomes Are Possible If DOD Can 

Apply Lessons from F/A-22 Program. GAO-03-645T. Washington, D.C.: 

April 11, 2003.

Best Practices: Capturing Design and Manufacturing Knowledge Early 

Improves Acquisition Outcomes. GAO-02-701. Washington, D.C.: July 15, 

2002.

Best Practices: Better Matching of Needs and Resources Will Lead to 

Better Weapon System Outcomes. GAO-01-288. Washington, D.C.: 

March 8, 2001.

F-22 Aircraft: Issues in Achieving Engineering and Manufacturing 

Development Goals. GAO/NSIAD-99-55. Washington, D.C.: March 15, 

1999.

Related GAO Products

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