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: Increment 2, the initial phase of modernization, addressed some requirements deferred from the acquisition program and added new ground attack capability. It has been fielded. Increment 3.1 began fielding in November 2011 and adds enhanced radar and enhanced air-to-ground attack capabilities. 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. 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 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. 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. 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. In contrast, the legacy programs we reviewed approached development of their aircraft as an incremental process in which initial capabilities 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 program(see app. II for a more detailed discussion of each program): 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. 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 to investigate the feasibility and operational utility of highly maneuverable lightweight fighter aircraft 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).