Report to the Committee on Armed 

Services, U.S. Senate 

United States Government Accountability Office

GAO 

March 2006 UNMANNED 

AIRCRAFT SYSTEMS 

New DOD Programs 

Can Learn from Past 

Efforts to Craft Better 

and Less Risky 

Acquisition Strategies 

GAO-06-447 
What GAO Found

United States Government Accountability Office

Why GAO Did This Study

Highlights

Accountability Integrity Reliability

www.gao.gov/cgi-bin/getrpt?GAO-06-447.

To view the full product, including the scope 

and methodology, click on the link above. 

For more information, contact Michael J. 

Sullivan at (202) 512-4841 or 

sullivanm@gao.gov. 

Highlights of GAO-06-447, a report to the 

Committee on Armed Services, U.S. 

Senate 

March 2006

UNMANNED AIRCRAFT SYSTEMS

New DOD Programs Can Learn from Past 

Efforts to Craft Better and Less Risky 

Acquisition Strategies 

While the Global Hawk and Predator both began as successful 

demonstration programs, they adopted different acquisition strategies that 

have led to different outcomes. With substantial overlap in development, 

testing, and production, the Global Hawk program has experienced serious 

cost, schedule, and performance problems. As a result, since the approved 

start of system development, planned quantities of the Global Hawk have 

decreased 19 percent, and acquisition unit costs have increased 75 percent. 

In contrast, the Predator program adopted a more structured acquisition 

strategy that uses an incremental, or evolutionary, approach to 

development—an approach more consistent with DOD’s revised acquisition 

policy preferences and commercial best practices. While the Predator 

program has experienced some problems, the program’s cost growth and 

schedule delays have been relatively minor, and testing of prototypes in 

operational environments has already begun. 

Since its inception as a joint program in 2003, the J-UCAS program has 

experienced funding cuts and leadership changes, and the recent 

Quadrennial Defense Review has directed another restructuring into a Navy 

program to develop a carrier-based unmanned combat air system. 

Regardless of these setbacks and the program’s future organization, DOD 

still has the opportunity to learn from the lessons of the Global Hawk and 

Predator programs. Until DOD develops the knowledge needed to prepare 

solid and feasible business cases to support the acquisition of J-UCAS and 

other advanced unmanned aircraft systems, it will continue to risk cost and 

schedule overruns and delaying fielding capabilities to the warfighter. 

Sought quantum leap in capabilities

Design relied on unproven technologies

Significant overlap of technology development, 

design, testing, and production

Risk tolerant leadership

Funding optimistic and compressed

in a few years

Incremental development of capabilities

Design relied more on proven technologies

Moderate overlap of testing and production 

Strong direction to follow defense acquisition 

policy preferences

Funding realistic and balanced over time

Global Hawk Predator

Sources: Northrop Grumman Corporation and General Atomics-Aeronautical Systems, Inc. (pictures).

 GAO analysis of DOD program data.

Through 2011, the Department of 

Defense (DOD) plans to spend $20 

billion to significantly increase its 

inventory of unmanned aircraft 

systems, which are providing new 

intelligence, surveillance, 

reconnaissance, and strike 

capabilities to U.S. combat 

forces—including those in Iraq and 

Afghanistan. 

Despite their success on the 

battlefield, DOD’s unmanned 

aircraft programs have experienced 

cost and schedule overruns and 

performance shortfalls. Given the 

sizable planned investment in these 

systems, GAO was asked to review 

DOD’s three largest unmanned 

aircraft programs in terms of cost. 

Specifically, GAO assessed the 

Global Hawk and Predator 

programs’ acquisition strategies 

and identified lessons from these 

two programs that can be applied 

to the Joint Unmanned Combat Air 

Systems (J-UCAS) program, the 

next generation of unmanned 

aircraft. 

What GAO Recommends

GAO recommends that DOD (1) 

limit Global Hawk production until 

the program demonstrates an 

integrated system and develops a 

new business case to justify future 

investments and (2) develop a 

sound business case and 

acquisition strategy for J-UCAS and 

follow-on efforts to ensure cost and 

schedule goals are met. DOD did 

not concur with our Global Hawk 

recommendations because it 

believes it is taking appropriate 

measures to manage risk. 
Page i GAO-06-447 Unmanned Aircraft Systems 

Letter 1

Results in Brief 2 

Background 3 

Global Hawk and Predator Had Common Beginnings, but Different 

Acquisition Strategies Have Yielded Different Outcomes 6 

J-UCAS Program Can Benefit from Lessons Learned by Global 

Hawk and Predator Programs 19 

Conclusions 22 

Recommendations for Executive Action 23 

Agency Comments and Our Evaluation 24 

Scope and Methodology 26 

Appendix I Unmanned Aircraft Systems Included in This Review 29 

Appendix II Comments from the Department of Defense 31 

Related GAO Products 35 

Tables 

Table 1: Defense Budget Requests for Unmanned Aircraft Systems 4 

Table 2: Changes in Global Hawk Funding, Quantity, and Unit 

Costs through Completion of the Program 9 

Table 3: Changes in Predator B Funding, Quantity, and Unit Costs 

through Completion of the Program 10 

Table 4: Comparison of Business Case and Acquisition Strategy 

Factors in Current Global Hawk and Predator Programs 11 

Figures 

Figure 1: Comparison of Predator B and Global Hawk Acquisition 

Plans with Best Practices Model 15 

Figure 2: Performance Characteristics of Unmanned Aircraft 

Systems Reviewed by GAO 30 

Contents 
Page ii GAO-06-447 Unmanned Aircraft Systems 

Abbreviations 

ACTD advanced concept technology demonstration 

DARPA Defense Advanced Research Projects Agency 

DOD Department of Defense 

J-UCAS Joint Unmanned Combat Air Systems 

OSD Office of the Secretary of Defense 

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Page 1 GAO-06-447 Unmanned Aircraft Systems 

March 15, 2006 

The Honorable John W. Warner 

Chairman 

The Honorable Carl Levin 

Ranking Minority Member 

Committee on Armed Services 

United States Senate 

Through 2011, the Department of Defense (DOD) plans to spend $20 

billion to develop, procure, and support a rapidly increasing inventory of 

unmanned aircraft systems.1

 Unmanned aircraft systems are providing 

combat forces—including those in Iraq and Afghanistan—with new 

intelligence, surveillance, reconnaissance, and strike capabilities that are 

helping to transform today’s military operations. The success of unmanned 

aircraft has led to greatly increased demand for new and improved 

platforms to be deployed into the field. While there have been successes 

on the battlefield, the development of unmanned aircraft systems has 

shared the same problems as other major weapon systems that begin an 

acquisition program too early, with many uncertainties about 

requirements, technology, design, and production. Likewise, the 

unmanned systems have also experienced similar outcomes—changing 

requirements, cost growth, delays in delivery, and reliability and support 

problems. 

Because of the expanding interest and promise in unmanned systems and 

sizable future investments, you asked us to review the Global Hawk, 

Predator, and Joint Unmanned Combat Air Systems—DOD’s three largest 

unmanned aircraft programs in terms of cost. Specifically, you asked us to 

(1) assess the Global Hawk and Predator programs’ business cases and 

acquisition strategies in terms of delivering their weapon systems on time 

and within cost, and (2) identify any lessons that can be learned and 

applied to the Joint Unmanned Combat Air Systems (J-UCAS) program as 

 1

 Until recently, DOD referred to these aircraft as “unmanned aerial vehicles.” The terms 

“unmanned aircraft” and “unmanned aircraft systems” are consistent with the Federal 

Aviation Administration’s classification and emphasizes that the aircraft is one component 

of the weapon system, which also includes payloads, ground stations, and communications 

equipment. 

United States Government Accountability Office

Washington, DC 20548 
Page 2 GAO-06-447 Unmanned Aircraft Systems 

it moves forward to develop a supportable business case and effective 

acquisition strategy.2

To assess these two objectives, we reviewed Global Hawk and Predator 

acquisition strategies and business cases and evaluated them according to 

best practices criteria utilizing GAO’s Methodology for Assessing Risks on 

Major Weapons System Acquisition Programs. We assessed budget, 

programmatic, and planning documents to determine the extent to which 

acquisition strategies were meeting warfighter requirements. We identified 

lessons learned from these and other programs and identified common 

factors that can contribute to J-UCAS’s success. We interviewed DOD and 

contractor officials and obtained programmatic data for these three 

systems. We leveraged prior work on other systems and on best practices 

of leading companies. We performed our review from August 2005 to 

February 2006 in accordance with generally accepted government auditing 

standards. 

The Global Hawk and Predator programs followed different acquisition 

strategies that resulted in different outcomes. While both programs began 

with top leadership support and accomplished successful, focused 

demonstration efforts, Global Hawk switched to a high-risk acquisition 

strategy by accelerating development and production of a new larger and 

more advanced aircraft. With the substantial overlap in development and 

production, the program experienced significant gaps in knowledge about 

technology, design, and manufacturing capabilities while requiring sizable 

funding. As a result, serious cost and schedule problems have ensued, 

some required capabilities have been deferred or dropped, operational 

tests have identified performance problems, and the Global Hawk program 

is being restructured. In contrast, the Predator program, which has also 

added a new, larger and more advanced aircraft, has pursued an 

acquisition strategy that is more structured and evolutionary and more 

consistent with DOD’s revised acquisition guidance and commercial best 

practices. While the Predator effort to acquire its larger model also has 

overlap in development and production and has experienced some 

problems, cost growth and schedule delays to date have been more 

moderate than those of Global Hawk, and flight testing of prototypes in 

operational environments has already begun. 

 2

 The committee also asked us to review the Army’s Extended Range/Multi-Purpose 

unmanned aircraft system, which we will report on separately. 

Results in Brief 
Page 3 GAO-06-447 Unmanned Aircraft Systems 

The J-UCAS program and its offspring could benefit from the lessons 

learned in the Global Hawk and Predator programs. Since its inception, 

the J-UCAS program has been in flux. Program management and goals 

have changed several times, and the recent Quadrennial Defense Review 

has directed another restructuring into a Navy program to demonstrate a 

carrier-based, air-refuelable unmanned combat air system. The Air Force 

plans to consider J-UCAS technologies and accomplishments in its efforts 

to develop a new long-range strike capability. Before DOD commits to 

major acquisition system development programs, it has the opportunity 

and time to develop the knowledge needed to prepare solid and feasible 

business cases and to adopt a disciplined, evolutionary strategy consistent 

with DOD acquisition policy preferences and best practices. 

We are recommending that the Secretary of Defense direct the Air Force 

to limit the production of Global Hawk B aircraft until integrated systems 

are demonstrated in testing and that the Global Hawk office update its 

business case to reflect the restructured program and justify future 

investments. We are also recommending that the Secretary direct the Navy 

and Air Force to advance with prudence in J-UCAS and follow-on efforts 

to ensure a sound business case and evolutionary, knowledge-based 

strategy guide any future programs and that the services remain 

committed to developing common components and operating systems to 

be more cost-effective and interoperable. DOD concurred with our J-UCAS 

recommendations, but did not concur with our Global Hawk 

recommendations. DOD stated that limiting Global Hawk production will 

incur significant costs and schedule delays, that risk and concurrency are 

being adequately managed, and that ongoing cost and evaluation efforts 

are thorough. We continue to believe that limiting Global Hawk 

procurement to allow technology to mature and thorough testing to occur 

will reduce future problems and lead to better program outcomes. Given 

the magnitude of changes and challenges facing the program, we also 

believe a comprehensive business case to justify and guide investments is 

needed. 

DOD expects unmanned aircraft systems to transform the battlespace with 

innovative tactics, techniques, and procedures and take on the so-called 

“dull, dirty, and dangerous missions” without putting pilots in harm’s way. 

The use of unmanned aircraft systems in military operations has increased 

rapidly since the fall of 2001, with some notable successes. Potential 

missions considered appropriate for unmanned systems have expanded 

from the original focus on the intelligence, surveillance, and 

reconnaissance mission area to limited tactical strike capabilities with 

Background 
Page 4 GAO-06-447 Unmanned Aircraft Systems 

projected plans for persistent ground attack, electronic warfare, and 

suppression of enemy air defenses. The Global Hawk, Predator, and Joint 

Unmanned Combat Air Systems are DOD’s three largest unmanned aircraft 

programs in terms of cost. (For more details on the three systems and 

their performance characteristics, see app. I.) 

Since the terror attacks in September 2001, defense investments in 

unmanned aircraft systems have exponentially increased. In the 10 years 

prior to the attacks, DOD invested a total of about $3.6 billion compared to 

the nearly $24 billion it plans to invest in the subsequent 10 years. DOD 

currently has about 250 unmanned aircraft in inventory and plans to 

increase its inventory to 675 by 2010 and to 1,400 by 2015. (These numbers 

are the larger systems and do not count numerous small and handlaunched systems used by ground forces.) 

In the fiscal year 2001 Defense Authorization Act, Congress set a goal that 

by 2010, one-third of DOD’s deep strike force will be unmanned in order to 

perform this dangerous mission;3

 this would significantly increase the 

number of unmanned aircraft in DOD’s inventory. In addition, foreign 

countries and other federal agencies, including the Department of 

Homeland Security and the Interior Department, are expressing interest in 

unmanned aircraft systems. Table 1 shows the funding in the fiscal year 

2006 Defense budget for research, development, procurement, and support 

of current and planned unmanned aircraft systems. 

Table 1: Defense Budget Requests for Unmanned Aircraft Systems 

(in millions of dollars by year of appropriation) 

 2005 2006 2007 2008 2009 2010 2011 Total 

Development and procurement $1,998.5 $1,670.3 $1,734.8 $1,983.8 $2,550.0 $2,643.4 $2,771.1 $15,351.9

Operationsa $167.3 $275.4 $338.7 $265.6 $295.4 $308.6 $342.0 $1,993.0

Basic and applied researchb $2,553.0

Total $2,165.8 $1,945.7 $2,073.5 $2,249.4 $2,845.4 $2,952.0 $3,113.1 $19,897.9

Source: “Unmanned Aircraft Systems Roadmap 2005-2030,” Office of the Secretary of Defense. 

a

Does not include 2005 supplemental funding for combat operations.

b

Annual breakdown of basic and applied research funding is not provided. 

 3

 Pub. L. No. 106-398, Appendix H.R. 5408, sec. 220 (2000). 
Page 5 GAO-06-447 Unmanned Aircraft Systems 

The 2006 Quadrennial Defense Review contained a number of decisions 

that would further expand investments in unmanned systems and their use 

in military operations. The report states DOD’s intent to nearly double 

unmanned aircraft coverage by accelerating the acquisition of the Predator 

and the Global Hawk. It also restructures the J-UCAS program to develop 

an unmanned, long-range carrier-based aircraft to increase naval reach 

and persistence. It further establishes a plan to develop a new land-based, 

penetrating long-range strike capability by 2018 and sets a goal that about 

45 percent of the future long-range strike force be unmanned. Officials 

told us that elements of the J-UCAS effort will be considered in Air Force 

analyses and efforts supporting future long-range strike capability. 

Unmanned aircraft systems are being developed under DOD’s acquisition 

policy, which emphasizes a knowledge-based, evolutionary approach to 

acquiring major weapon systems. This approach separates technology 

development from product development, as suggested by best practices. In 

implementing the policy, a critical first step to success is formulating a 

comprehensive business case that justifies the investment decision to 

begin development. The business case should validate warfighter needs 

and match product requirements to available resources, including proven 

technologies, sufficient engineering capabilities, adequate time, and 

adequate funds. Several basic factors are critical to establishing a sound 

business case for undertaking a new product development. First, the user’s 

needs must be accurately defined, alternative approaches to satisfying 

these needs properly analyzed, and quantities needed for the chosen 

system must be well understood. The developed product must be 

producible at a cost that matches the users’ expectations and budgetary 

resources. Finally, the developer must have the resources to design the 

product with the features that the customer wants and to deliver it when it 

is needed. If circumstances substantially change, the business case should 

be revisited and revised as appropriate. If the financial, material, and 

intellectual resources to develop the product are not available, a program 

should not move forward. 

Best practices indicate that the business case is best accomplished using 

an evolutionary (or incremental) approach that plans to deliver an early 

but relevant capability first, followed by definable and doable increments 

that ultimately achieve the full capability. Each increment is expected to 

have its own decision milestones and baseline—cost, schedule, and 

performance requirements. An acquisition strategy is the disciplined 

process employed by the service program office and prime contractor to 

manage the acquisition, deliver knowledge at key junctures to make 

Best Practices for 

Achieving Successful 

Acquisition Outcomes 
Page 6 GAO-06-447 Unmanned Aircraft Systems 

further investments, and continue the program. The strategy implements 

the business case; sets schedules for developing, designing, and producing 

the weapon system; and establishes exit/entrance criteria to guide 

acquisition managers and executives through key program milestones to 

control and oversee the acquisition. 

While the Global Hawk and Predator both began as successful advanced 

concept technology demonstration (ACTD) programs, they have since 

adopted different strategies in system development that have led to 

different outcomes. The Global Hawk adopted a riskier acquisition 

strategy that has led to significant cost, schedule, and performance 

problems. Conversely, the Predator program pursued a more structured 

and evolutionary strategy more consistent with DOD’s acquisition policy 

guidance and has thus far experienced fewer negative outcomes. 

Following a successful ACTD, DOD approved an acquisition program in 

2001 to incrementally develop and acquire systems similar to the 

demonstrators, now designated the RQ-4A (Global Hawk A). In 2002, the 

Global Hawk program was substantially restructured to more quickly 

develop and field a new, larger, and more advanced aircraft, designated 

the RQ-4B (Global Hawk B). The new acquisition strategy was now highly 

concurrent, overlapping technology development, design, testing, and 

production. Our November 2004 report on Global Hawk, raised concerns 

about the revised strategy and its elevated risks of poor cost, schedule, 

and performance outcomes. 4

 We recommended limiting procurement to 

only those aircraft needed for testing to allow product knowledge to more 

fully mature and the design and technologies to be tested before 

committing resources to the full program. DOD officials did not agree 

because, in their opinion, we overstated some risks and they were 

effectively mitigating other risks. 

The Global Hawk program is already experiencing problems that are 

associated with high concurrency and gaps in product knowledge. 

Production of the larger Global Hawk B aircraft began in July 2004 with 

 4

 GAO, Unmanned Aerial Vehicles: Changes in Global Hawk’s Acquisition Strategy Are 

Needed to Reduce Program Risks, GAO-05-6 (Washington, D.C.: Nov. 5, 2004). 

Global Hawk and 

Predator Had 

Common Beginnings, 

but Different 

Acquisition Strategies 

Have Yielded 

Different Outcomes 

Global Hawk Program Has 

Experienced Relatively 

Poor Outcomes 
Page 7 GAO-06-447 Unmanned Aircraft Systems 

immature technologies and an unstable design. The design had been 

expected to be very similar to the smaller Global Hawk A, whose 

performance had been proven in the ACTD, but as the larger aircraft 

design matured and production geared up, the differences were more 

extensive, complex, and costly than anticipated. Within a year, there were 

more than 2,000 authorized engineering drawing changes to the total 

baseline of 1,400 drawings, and more than half were considered major 

changes. Also, once manufacturing began, there were recurring quality and 

performance issues on the work of several key subcontractors. The 

subcontractor building the tail scrapped seven of the first eight main 

structural components because of design changes and manufacturing 

process deficiencies. The wing manufacturer had to terminate a key 

subcontractor because of poor performance and quality. Other suppliers 

delivered parts late and with defects. These specific problems have mostly 

been resolved, but the potential for even greater problems exists when the 

major subsystems, still in development, are integrated into the new larger 

aircraft already being produced. 

Outcomes so far have not been good, as the program has experienced 

significant cost increases. Extensive design changes contributed to a $209 

million overrun in the development contract and resulted in a more 

expensive production aircraft than forecast. Requirements growth, 

increased costs of airframe and sensors, and increased support 

requirements significantly increased procurement costs. In April 2005, the 

Air Force reported to Congress a Nunn-McCurdy breach in procurement 

unit costs—an 18 percent increase over the program’s cost baseline 

approved in 2002.5

 In December 2005, we reported the Air Force had failed 

to report $401 million in procurement costs and that the procurement unit 

cost had actually increased 31 percent.6

 Subsequently, in December 2005, 

the Air Force renotified Congress that, if these additional costs were 

included, the procurement unit costs had actually increased by over 25 

percent and that program acquisition unit costs (including development 

and military construction costs in addition to procurement) had also 

breached the thresholds established in the law. Under the law, DOD must 

 5

 To provide for oversight of cost growth in DOD major defense acquisition programs, 

Congress passed legislation in 1982, commonly referred to as Nunn-McCurdy, that, as 

amended, requires DOD to notify Congress when a program’s unit cost growth exceeds (or 

breaches) the latest approved acquisition program baseline by at least 15 percent. This 

requirement is codified at 10 U.S.C. 2433. 

6

 GAO, Unmanned Aircraft Systems: Global Hawk Unit Price Increases Understated in 

Nunn-McCurdy Report, GAO-06-222R (Washington, D.C.: December 15, 2005). 
Page 8 GAO-06-447 Unmanned Aircraft Systems 

now certify the program to Congress.7 The Air Force is currently 

restructuring the Global Hawk program—the fourth restructuring since it 

began as a major acquisition. 

Program schedules and performance have also been negatively affected. 

For example, the start of operational assessment of the Global Hawk A 

slipped about 1 year, and the planned start of initial operational testing of 

the Global Hawk B design has slipped 2 years. The Director, Operational 

Test and Evaluation, reports that operational assessment of the Global 

Hawk A identified significant deficiencies in processing and providing data 

to the warfighter, communication failures, and problems with engine 

performance at high altitudes. In addition, planned delivery dates have 

continued to slip, the procurement for two aircraft were moved to later 

years, and some development work content was deferred or deleted; this 

means that the warfighter will not get anticipated capability at the time 

originally promised. For example, defensive subsystems required by Air 

Combat Command have been pushed off the schedule, and it is not known 

whether they will be added in the future. 

The frequent deployment of Global Hawk demonstrator aircraft to support 

combat operations has further affected costs and schedule, according to 

officials. Support to the warfighter is the program’s top priority. 

Deployments have resulted in increased costs and time delays for 

acquisition but, at the same time, provide a valuable, realistic test for the 

system and its employment concepts to improve its performance and 

responsiveness to the warfighter. Fleet flying hours now exceed 8,000 

hours, more than half in combat operations. 

The following table shows changes in cost and quantities since the 

program started in March 2001. The restructured program tripled 

development costs, reflecting the addition of the new Global Hawk B 

aircraft with advanced capabilities still in technology development. Total 

procurement costs increased moderately, resulting from higher costs for 

the new aircraft tempered by a reduction in the number of aircraft to be 

acquired for reasons of affordability and changed requirements. Total 

program acquisition and procurement unit costs have increased 73 percent 

 7

 If the cost growth has increased at least 25 percent over the baseline, the Secretary of 

Defense must certify to Congress that (1) the program is essential to national security, (2) 

no alternatives exist which will provide equal or greater military capability at less cost, (3) 

new program acquisition or procurement unit cost estimates are reasonable, and (4) the 

management structure is adequate to control unit cost. 
Page 9 GAO-06-447 Unmanned Aircraft Systems 

and 35 percent, respectively, and aircraft quantities decreased by 19 

percent. Thus far, seven Global Hawk As have been delivered to the Air 

Force—14 percent of the combined fleet—and 34 percent of the planned 

budget to completion has been invested. 

Table 2: Changes in Global Hawk Funding, Quantity, and Unit Costs through 

Completion of the Program 

(in millions of base year 2006 dollars)

Cost March 2001 January 2006 Changes Percent

Development $925.2 $2,459.1 $1,533.9 166%

Procurement $3,836.2 $4,197.5 $361.3 9%

Total $4,761.4 $6,656.6 $1,895.2 40%

 

Quantity 

Aircraft 63 51 -12 -19%

Ground stations 14 10 -4 -29%

 

Unit Costs 

Total program $75.6 $130.5 $54.9 73%

Procurement only $60.9 $82.3 $21.4 35%

 

Source: DOD data, GAO analysis. 

Note: Procurement costs include costs for aircraft, ground stations, support equipment, and spares. 

Military construction funding is not included. 

The Predator program began in 1994 as an ACTD to demonstrate and 

deliver what would become the MQ-1 (Predator A). It evolved from an 

earlier unmanned aircraft, the Gnat, allowing delivery of an initial 

demonstrator aircraft to DOD 6 months after contract award. The Predator 

ACTD concluded in 1996 and transitioned to the Air Force in 1997 when 

the Defense Acquisition Board approved the Predator A for production. A 

limited strike capability, to launch Hellfire missiles against ground targets, 

was later added. On the basis of the success of the Predator A, the 

contractor designed and built two prototypes of a larger aircraft capable of 

armed reconnaissance and surveillance. This new aircraft would evolve 

into the second generation MQ-9 (Predator B), a larger and higher-flying 

aircraft with more strike capability. In February 2004, the Predator B 

program was approved as a new system development and demonstration 

Predator Program Has Had 

Better Outcomes than 

Global Hawk 
Page 10 GAO-06-447 Unmanned Aircraft Systems 

program. It is managed separately from Predator A and has its own 

schedule and management reviews. 

The Predator program overall has experienced fewer cost, schedule, and 

performance problems than the Global Hawk program has experienced. 

As of February 2006, the Predator A program has a stable design with little 

cost growth and the Air Force recently increased its planned buys. 

Although early in the acquisition cycle, cost increases in the Predator B 

program have been moderate and schedule changes few. The fiscal year 

2005 report of the Director, Operational Test and Evaluation, cited 

favorable developmental testing results and recommended refining 

acquisition and fielding strategies to permit more focused and effective 

operational testing. To date, about 59 percent of the combined fleet (as 

presented in last year’s budget) has been delivered for about 56 percent of 

the current planned budget. Deliveries include 129 Predator As and 2 

prototype and six production Predator Bs. The combined fleet has tallied 

120,000 flight hours since 1995. Congress has been supportive of both 

Predators, typically adding to annual funding requests and quantities. 

Table 3 summarizes changes in the Predator B program estimates to 

completion since its start of system development. 

Table 3: Changes in Predator B Funding, Quantity, and Unit Costs through 

Completion of the Program 

(in millions of base year 2006 dollars)

Cost February 2004 January 2006 Changes Percent

Development $153.6 $177.5 $23.9 16%

Procurement $935.1 $1,031.9 $96.8 10%

Total $1,088.7 $1,209.4 $120.7 11%

 

Quantity 

Aircraft 63 63 $0.0 0%

 

Unit Costs 

Total program $17.3 $19.2 $1.9 11%

Procurement only $14.8 $16.4 $1.5 10%

Source: DOD data, GAO analysis. 

Note:. Procurement costs include costs for aircraft, ground stations, support equipment, and spares. 

Military construction funding is not included. Totals may not equal 100 because of rounding. 
Page 11 GAO-06-447 Unmanned Aircraft Systems 

The Global Hawk and Predator began with top leadership support and 

successful demonstration efforts as ACTDs, but differences in their 

business practices have been the primary contributors to different cost, 

schedule, and performance outcomes so far in these programs. Both 

programs were under pressure to field capabilities quickly to support the 

warfighter. Original models of both systems have proven to be valuable 

assets in combat operations, and both transitioned from technology 

demonstrations into weapon system acquisition programs with sound 

strategies to complete development and acquire initial systems with 

enhanced capabilities. However, Global Hawk subsequently changed to a 

riskier acquisition strategy that plans to develop technologies concurrently 

with the system design, testing, and production phases of the program. 

Predator, while not immune to typical developmental problems, has 

pursued a more disciplined, structured approach intended to evolve new 

capability in separate programs. Its decisions have been more consistent 

with DOD’s acquisition policy preferences. Table 5 shows some of the 

differences of the current programs that have led to greater success in the 

Predator program so far. 

Table 4: Comparison of Business Case and Acquisition Strategy Factors in Current Global Hawk and Predator Programs 

Acquisition factors Global Hawk Predator 

Acquisition strategy Quantum leap Incremental 

Technologies Immature Mostly mature 

Concurrency Significant overlap of technology development, 

design, testing, and production 

Moderate overlap of technology development, 

testing, and production 

Leadership Less directive and more risk-tolerant Direction to follow acquisition policy preferences 

Funding Optimistic and compressed into a few years Moderate and balanced over time 

Source: GAO analysis of DOD program data. 

The current Global Hawk acquisition strategy is risky. It plans to develop a 

new, larger, and more capable aircraft by integrating as yet 

undemonstrated technologies into a new airframe, also undemonstrated, 

to provide a quantum leap in performance over its ACTD. The Predator 

also added plans for a new, larger aircraft, but chose an incremental 

approach by managing the new investment in a separate program with 

separate decision points. 

The Global Hawk program began in 1994 as an ACTD, managed first by the 

Defense Advanced Research Projects Agency and, since 1998, by the Air 

Force. Seven demonstrator aircraft were built, logged several thousand 

Differences in Global 

Hawk and Predator 

Business Practices Have 

Contributed to the 

Programs’ Outcomes to 

Date 

Global Hawk’s Acquisition 

Strategy Is More Risky than 

Predator’s 
Page 12 GAO-06-447 Unmanned Aircraft Systems 

flight hours, completed several demonstrations and other tests, and passed 

a military utility assessment. Demonstrators subsequently provided 

effective support to military operations in Iraq and Afghanistan. DOD 

judged the demonstration a success, but tests identified the need to make 

significant improvements in reliability, sensor performance, and 

communications before producing operationally effective and suitable 

systems. 

In March 2001, DOD approved the Global Hawk for a combined start of 

system development and limited initial production of six aircraft. The Air 

Force’s acquisition strategy approached best practices standards in terms 

of technology and design maturity. Officials planned to first acquire basic 

systems very similar to the successful demonstrators and then 

incrementally develop and acquire systems with more advanced sensors as 

critical technologies were demonstrated, using the same platform. 

Officials planned to acquire a total of 63 aircraft (Global Hawk As), and 14 

ground stations for mission launch, recovery, and control. These aircraft 

would all be dedicated to single missions, some having imagery 

intelligence capabilities and others having signals intelligence capabilities. 

In 2002, the Air Force radically restructured the Global Hawk program to 

develop and acquire a larger and more advanced aircraft system, the 

Global Hawk B. The decision to acquire the larger aircraft was driven by 

the desire to have multimission capabilities (both signals intelligence and 

imagery intelligence sensors on the same aircraft) and to deliver new 

capabilities associated with advanced signals intelligence and radar 

technologies still in development. The new acquisition strategy abandoned 

an incremental approach and moved toward a strategy that called for 

concurrent development of technologies, systems integration, testing, and 

production. The Air Force planned to set and approve requirements and 

mature technologies over time, instead of at the start of development, and 

to do this at the same time as it designed and produced the new larger and 

heavier aircraft that had never been built or flight-tested. 

For affordability reasons and changing requirements, the restructured 

program also reduced quantities to 51 aircraft—7 Global Hawk As and 44 

Global Hawk Bs—and 10 ground stations. Most of the Global Hawk Bs are 

planned to have multimission capabilities, including the advanced signals 

intelligence sensor, and some will have single-mission capabilities, 

including the advanced radar. Low-rate production was tripled from the 6 

Global Hawk As approved at program start to 19 aircraft as restructured—

7 Global Hawk As and 12 Global Hawk Bs—about 40 percent of the entire 

fleet. To speed up development and field these new capabilities sooner, 
Page 13 GAO-06-447 Unmanned Aircraft Systems 

DOD also approved the program to streamline and accelerate acquisition 

processes, bypassing some normal acquisition policy requirements and 

controls when considered appropriate. For example, the Global Hawk B 

business case did not include a comprehensive analysis of alternatives that 

is intended to rigorously compare expected capabilities of a new system 

with the current capabilities offered by existing weapon systems, such as 

the signals intelligence capabilities provided by U-2 aircraft. 

Although the program could have reduced cost and schedule risks by 

managing a series of discrete increments to develop and acquire the 

different configurations, the Air Force chose to manage it as one program, 

with one baseline and one set of decision milestones. This revised strategy 

attempts to deliver capability to the warfighter that significantly surpasses 

that of the former Global Hawk A program. And the Air Force has 

committed up-front to produce the larger Global Hawk B aircraft in order 

to deliver new capabilities to the warfighter sooner, but the signals 

intelligence sensor and advanced radar technologies critical to meeting 

requirements are still immature and are not expected to be delivered and 

integrated until very late in the program. 

The Predator transitioned from its ACTD program in 1997, when the 

Defense Acquisition Board approved the Predator A for production, 

skipping the system development and design phases. The transition was 

not without difficulty because the focus during the demonstration effort 

had been to quickly ascertain operational capabilities, but without 

emphasis on design and development aspects that make a system more 

reliable and supportable—typically key aspects of a development program. 

The Air Force had to organize a team to respond to these issues until 

reliability and supportability issues could be resolved. Senior leadership, 

however, kept the strategy simple and focused on buying additional 

Predators very similar to the ACTD models. 

In February 2004, the Predator B program was approved as a new system 

development and demonstration program. The Predator B program was 

approved without two fundamental elements of a good business case: 

formal requirements documentation and an analysis of alternatives. 

According to the Air Force, these were not prepared because of the 

exigencies of the Global War on Terror. Officials initially planned to adopt 

an acquisition strategy similar to the Global Hawk’s, but senior leadership 

intervened and the acquisition strategy adopted was incremental and more 

consistent with DOD acquisition policy preferences. Under the revised 

strategy, the Air Force manages the Predator A and B acquisitions as 

separate programs. The new Predator B program balanced requirements 
Page 14 GAO-06-447 Unmanned Aircraft Systems 

and resources for a first increment and included its own sets of milestone 

decision points. Subsequent increments will evolve when future 

requirements and resources can be matched. 

Figure 1 contrasts notional Predator B and Global Hawk schedules for 

implementing their respective acquisition strategies with that espoused by 

best practices and DOD acquisition policy. Predator’s incremental 

approach with less overlap of technology and system development is more 

similar to best practices. 
Page 15 GAO-06-447 Unmanned Aircraft Systems 

Figure 1: Comparison of Predator B and Global Hawk Acquisition Plans with Best Practices Model 

Critical technologies were not sufficiently mature to support the start-up 

of the Global Hawk B program—particularly those associated with the 

signals intelligence and advanced radar, the very capabilities that drove 

the decision to acquire the larger aircraft. Likewise, the larger and heavier 

Global Hawk’s Technologies 

Are Much Less Mature than 

Predator’s 

Initial operational test and evaluation 

Increment 1

Production start

Product development start

Increment 2

Initial operational test and evaluation 

Production start

Product development start

Initial operational test and evaluation 

Increment 1

Product development start

Production start

Increment 2

Product development start

Production start

Best practices

Predator B

Production s Initial operational test and evaluation tart

Product development start

Global Hawk

Technology development

System development

Production

Source: DOD data, GAO analysis.
Page 16 GAO-06-447 Unmanned Aircraft Systems 

aircraft was neither prototyped nor demonstrated. The Predator B’s 

technologies were mostly mature at program start, and the aircraft has 

been built and flown. Mature technologies can leverage the potential for 

success in development, providing early assurance that the warfighter’s 

requirements can be met within cost and schedule goals. 

Although Global Hawk A technologies were demonstrated in the ACTD, 

the level of technology maturity significantly declined when Global Hawk 

B was approved for development. In particular, the new signals 

intelligence and multiplatform radar systems were still in technology 

development, not expected to be mature and be tested in an operational 

environment until sometime between 2009 and 2011. The spillover of 

technology development into product development and overall immaturity 

of technology increase risks of poor cost, schedule, and performance 

outcomes. For example, as the advanced sensors mature and become 

ready to be integrated into the aircraft, there is risk that the aircraft, 

already being produced, will not have sufficient space, power, or cooling 

or that the sensor systems will weigh more than planned, reducing aircraft 

performance and ability to meet overall mission requirements—altitude, 

speed, and endurance. 

Predator A has been in production since 1997 and its technologies are 

mature. All Predator B technologies, except for one, are mature. This one 

meets the DOD standard for maturity—demonstration in a lab 

environment—but has not yet met best practice standards that require 

demonstrations in an operational environment. This technology is 

important to manage the weapons that Predator B will carry and launch—

more than those on Predator A. It relies on a data link that enables the 

operator to release the weapon from the ground. Program officials have 

stated that the current problems with this technology are related to its 

integration into the Predator B weapon system. In unmanned aircraft, 

unlike manned aircraft, there is no one in the cockpit to fire the weapon. 

To develop this capability required revisions to software, cryptologic 

controls, navigation sensors, and flight operations. The Air Force expects 

this capability to be demonstrated in an operational environment after it 

has been integrated into a Predator B in May 2006. 

The Global Hawk’s restructured program includes a significant overlap of 

technology, design, and production. The Predator B program is also 

concurrent, but to a lesser degree. Concurrency—the overlapping of 

development, test, and production schedules—is risky and can be costly 

and delay delivery of a usable capability to the warfighter if testing shows 

design changes are necessary to achieve expected system performance. 

Global Hawk and Predator 

Both Include Concurrent 

Development and Production 
Page 17 GAO-06-447 Unmanned Aircraft Systems 

Once in production, design changes can be an order of magnitude greater 

than changes identified during the design phase. 

By requiring a larger air vehicle to carry new advanced technologies while 

speeding up the acquisition schedule, the Air Force accepted much higher 

risks than the original plan, which followed a more evolutionary approach. 

The Air Force restructured the Global Hawk program, extending the 

development period, delaying testing, and accelerating aircraft production 

and deliveries, resulting in substantial concurrency. The development 

period was expanded by 5 years, and production deliveries were 

accelerated and compressed to fewer years, creating significant overlap 

from fiscal years 2004 to 2010. As a result, the Air Force plans to buy 

almost half of the new larger Global Hawk aircraft before a production 

model is flight-tested and operational evaluations are completed to show 

that the air vehicle design works as required. Substantially more than half 

of the aircraft will be purchased before the airborne signals intelligence 

and multiplatform radar, the two technologies that are required for the 

larger aircraft, complete development and are integrated for flight testing. 

The Predator B program’s revised strategy also overlapped development 

and production. For example, 21 Predator aircraft will be purchased 

before initial operational test and evaluation has been completed. Air 

Force officials acknowledge that the concurrency will require them to 

modify about 10 of these aircraft to bring them up to the full first 

increment capability. Modifications will include the installation of the 

system to manage and launch weapons and the digital electronic engine 

controller. 

Top management attention set the stage for the early success of Global 

Hawk. The Under Secretary of Defense for Acquisition, Technology, and 

Logistics became personally involved in establishing the original plan for 

development. Leadership insisted on fielding an initial capability that 

could be developed within a fixed budget while providing for an 

evolutionary process to add enhancements to succeeding versions. The 

result was a very successful ACTD program that produced seven 

demonstrators, logged several thousand flight hours, passed its military 

usefulness assessment, and has since very effectively supported combat 

operations in Afghanistan and Iraq. Once the Global Hawk was approved 

as a major acquisition program, however, senior Air Force leaders diverted 

Global Hawk to a high-risk spiral development strategy that featured 

frequent changes to development plans and time frames. They also 

approved the larger Global Hawk B with immature critical technologies 

Different Leadership 

Approaches Have Influenced 

Outcomes in Both Programs 
Page 18 GAO-06-447 Unmanned Aircraft Systems 

and a highly concurrent test and production program—much of this 

contrary to best practices and defense acquisition policy preferences. 

The Predator also had top management attention early in the program and 

has maintained its high visibility through a high-ranking group of Air Force 

executives known as Task Force Arnold. Established in 2002 as a senior 

oversight body for the Predator, Task Force Arnold has provided guidance 

and headquarters-level direction to Air Combat Command on the needs 

and capabilities for the system. The group has played a valuable role in 

helping the Predator program maintain a tight focus on program 

requirements and direction. Once the Predator A became operational, Air 

Combat Command was besieged by requests from combatant commanders 

for additional enhancements or capabilities. To alleviate the problem, the 

task force acted as the arbiter for operational requirements. New 

capabilities had to be vetted and prioritized through the task force before 

they were incorporated. This kept a balance between requirements and 

available resources and reduced the burden on Air Combat Command and 

the program office, enabling the program to better manage its 

requirements. 

The task force was instrumental in revising the Predator B plans and 

acquisition strategy. On the basis of an assessment from Task Force 

Arnold, the Secretary of the Air Force directed that the program office 

field an interim combat capability to balance an urgent operational need 

with new acquisition. The Secretary also directed that the program office 

revise its acquisition strategy to incrementally develop the Predator. 

Accordingly, the Air Force restructured the program, dropping the spiral 

development plan for an incremental approach. This strategy extended the 

production schedule by 5 years and delayed initial operating capability by 

3 years—lessening the degree of concurrency and providing more time to 

mature technology and design. Whereas the original strategy called for 

procuring 8 operational aircraft by August 2005, the revised, more 

conservative strategy plans to acquire 6 aircraft delivered 1 year later. 

Global Hawk funding requirements are optimistic, have changed, and 

continue to increase. In 2002 Global Hawk tripled estimated development 

costs and compressed the procurement of aircraft into fewer years. 

Program funding, which previously had been allocated relatively evenly 

across 20 years, was compressed into roughly half the time, tripling Global 

Hawk’s budgetary requirements in certain years. This adds to funding risk 

should large annual amounts be unaffordable as they compete with other 

defense priorities. The Air Force is currently preparing a new acquisition 

Global Hawk Funding 

Requirements Are More 

Compressed than Those of the 

Predator 
Page 19 GAO-06-447 Unmanned Aircraft Systems 

baseline estimate, its fourth baseline since the program started in March 

2001. 

In contrast, Predator funding requirements are less optimistic and are 

spread over a longer production period. The stable Predator A program 

has been in production since 1997 and had been focused on replacing 

aircraft lost through attrition. However, the Air Force increased its buy 

quantities in the fiscal year 2007 budget to reflect increased future force 

requirements. The revised acquisition strategy for the Predator B extended 

the production period by 5 years and decreased annual buy quantities, 

resulting in more even and achievable levels of annual funding. Annual 

funding for both Predators has been increased by Congress in recent 

years, enabling the Air Force to procure additional Predator systems or 

make enhancements to the fielded systems. 

J-UCAS represents the next generation of unmanned aircraft. In addition 

to providing intelligence and surveillance capabilities, J-UCAS is being 

designed as a heavily weaponized and persistent strike aircraft. The joint 

Air Force and Navy technology demonstration combined the two services’ 

separate efforts to develop early models of advanced unmanned attack 

systems. Since the pre-acquisition program was initiated in 2003, it has 

experienced funding cuts and leadership changes. The recent Quadrennial 

Defense Review calls for again restructuring the program into a Navy 

effort to demonstrate an unmanned carrier-based system. Regardless of 

future organization, DOD still has the opportunity to learn from the 

lessons of the Global Hawk and Predator programs to develop the 

knowledge needed to prepare solid and feasible business cases to support 

advanced unmanned aircraft acquisitions. 

Before J-UCAS was established as a joint program, the Air Force and Navy 

had separate unmanned combat aircraft projects under way, each in 

partnership with the Defense Advanced Research Projects Agency 

(DARPA). In 2003, we reported that the Air Force’s original business plan 

provided time to mature technologies and was a relatively low-risk 

approach, but that plans and strategy had changed to a much accelerated 

and higher-risk approach.8

 The new plan proposed to increase 

 8

 GAO, Defense Acquisitions: Matching Resources with Requirements Is Key to the 

Unmanned Combat Air Vehicle Program’s Success, GAO-03-598 (Washington D.C.: June 

30, 2003). 

J-UCAS Program Can 

Benefit from Lessons 

Learned by Global 

Hawk and Predator 

Programs 

J-UCAS Plans and 

Acquisition Strategy 

Continue to Evolve 
Page 20 GAO-06-447 Unmanned Aircraft Systems 

requirements and accelerate the schedule for development and 

production, substantially increasing concurrency of development, test, and 

production activities. The gaps in product knowledge and the unfinished 

technology development added significant risks of poor cost, schedule, 

and performance outcomes. Therefore, we supported DOD’s decision, 

under discussion at the time of our review, which advocated a new joint 

service approach and which reduced risks by significantly slowing down 

the Air Force’s plans. 

DARPA was then designated to lead a joint demonstration program with 

Air Force and Navy participation. The joint office began operations in 

October 2003 and devised a $5 billion pre-acquisition program that would 

develop and demonstrate larger and more advanced versions of the 

original Air Force and Navy prototypes (three from each contractor for a 

total of six aircraft). The office planned to conduct an operational 

assessment starting in 2007 and use the results to inform Air Force and 

Navy decisions for possible system acquisition starts in 2010. The 

demonstrators were expected to meet both the Air Force and Navy 

requirements and to share a common operating system, sensors, and 

weapons. Compared with the revised Air Force plans, the joint approach 

provided a more knowledge-based strategy with decreased risks of poor 

outcomes. The joint strategy delayed the start of system development, 

providing more time to mature the technologies, incorporate new 

requirements, and conduct demonstrations with prototype aircraft. 

In December 2004, the Office of the Secretary of Defense (OSD) reduced 

programmed funding by $1.1 billion and directed that funding and 

leadership be transitioned to the Air Force, with Navy participation, and 

that the joint program be restructured. The funding and leadership 

perturbations added about 19 months to the schedule for completing 

technology demonstration and deciding whether to start new system 

developments. The plan then was to develop and demonstrate five aircraft 

to inform system development decisions in fiscal year 2012. 

Now it appears the J-UCAS program will change one more time as the 2006 

Quadrennial Defense Review directed its restructuring into a Navy 

program to develop an unmanned longer-range carrier-based aircraft 

capable of being air-refueled to provide greater standoff capability, to 

expand payload and launch options, and to increase naval reach and 

persistence. The Quadrennial Defense Review also directed speeding up 

efforts to develop a new land-based, penetrating long-range capability to 

be fielded by 2018. The Air Force is expected to use the accomplishments 

and technologies from the restructured J-UCAS program to inform the 

upcoming analysis of alternatives for the next generation long range strike 
Page 21 GAO-06-447 Unmanned Aircraft Systems 

program. The Air Force has a goal that approximately 45 percent of its 

future long-range strike force will be unmanned. Although the J-UCAS and 

follow-on efforts appear somewhat unstable as they go through these 

changes, we see benefits to this. Addition of requirements and changes in 

user needs can be determined prior to full program initiation. If done after 

an acquisition begins systems integration, these perturbations would be 

much more costly. 

The Navy’s restructured J-UCAS program, the Air Force’s new long-range 

strike effort, and other future programs have opportunities to learn 

lessons from the Global Hawk and Predator programs. As originally 

envisioned, the J-UCAS demonstration effort provided for an extended 

period of time to define warfighter requirements, mature and demonstrate 

technologies, inform the design with systems engineering, and conduct a 

thorough operational assessment to prove concepts and military utility. 

These kinds of actions would establish a foundation for a comprehensive 

business case and effective acquisition strategy. Key lessons that can be 

applied to J-UCAS and its offspring include 

• maintaining disciplined leadership support and direction similar to that 

experienced early in Global Hawk from the Under Secretary of Defense 

for Acquisition, Technology, and Logistics and with the Predator’s Task 

Force Arnold; 

• establishing a clear business case that constrains individual program 

requirements to match available resources based on proven 

technologies and engineering knowledge before committing to system 

development and demonstration; 

• establishing an incremental acquisition strategy that separates 

technology development from product development and minimizes 

concurrency between testing and production; 

• establishing and enforcing controls that require knowledge and 

demonstrations to ensure that appropriate knowledge is captured and 

used at critical decision junctures before moving programs forward 

and investing more money; and 

• managing according to realistic funding requirements that fully 

resource product development and production based on a cost 

estimate that has been informed by proven technologies and a 

preliminary design. 

Additionally, lessons of the Global Hawk and Predator transitions from 

ACTDs into production and operation are important. The advanced 

concept technology demonstration can be a valuable tool to prove 

Lessons Learned 
Page 22 GAO-06-447 Unmanned Aircraft Systems 

concepts and military utility before committing time and funds to a major 

system acquisition. However, designing in product reliability and 

producibility and making informed trade offs among alternative support 

approaches are key aspects of development. If these operational aspects 

of system development are not addressed early before production, they 

can have major negative impacts on life cycle costs. 

Finally, as the J-UCAS evolves one more time—and efforts return to the 

individual services—some key challenges will exist to maintain the 

advantages that were offered by a joint effort. The services need to be 

aware of those advantages and not arbitrarily reject them for parochial 

reasons. For example, exploiting past plans for common operating 

systems, components, and payloads is important to affordability. Common 

systems offer potential for cost savings as well as improved 

interoperability. In particular, the common operating system pursued by 

DARPA is a cutting edge tool to integrate and provide for interoperability 

of air vehicles, allowing groups of unmanned aircraft to fly in a 

coordinated manner and function autonomously (without human input). 

Global Hawk’s high-risk acquisition strategy resulted in increased costs 

and delays. The restructured Global Hawk program is very different from 

the original program that was approved in 2001 for a combined start of 

development and limited production. The restructured program replaced 

the original strategy to slowly and incrementally develop and acquire 

enhanced versions of the proven demonstrator, with a highly concurrent 

and accelerated strategy to develop and acquire a substantially new 

aircraft with much advanced capabilities still in technology development. 

Despite these major changes, officials essentially overlaid the new plans 

on the old and did not prepare a comprehensive business case to support 

the larger aircraft and justify specific quantities of the advanced signals 

intelligence and advanced radar capabilities. Predator B’s strategy is less 

risky, and as a result, the program has had moderate cost growth and has 

delivered assets in a timely manner. 

There are trends that run consistently through the Global Hawk and 

Predator programs, similar to trends in other major defense acquisition 

programs that we have reviewed. That is, when DOD provides strong 

leadership at an appropriate organizational level, it enables innovative, 

evolutionary, and disciplined processes to work. Once leadership is 

removed or diminished, programs have tended to lose control of 

requirements and add technical and funding risks. We have also found that 

after successful demonstrations to quickly field systems with existing 

Conclusions 
Page 23 GAO-06-447 Unmanned Aircraft Systems 

technologies, problems were encountered after the programs transitioned 

into the system development phase of the acquisition process. The 

services pushed programs into production without maturing processes 

and also began to add new requirements that stretched beyond technology 

and design resources. Inadequate technology, design, and production 

knowledge increased risk and led to cost, schedule, and performance 

problems. 

J-UCAS has had a bumpy road with several changes in leadership and 

strategic direction. However, J-UCAS and its offspring as directed by the 

Quadrennial Defense Review will be at a good juncture to establish a 

sound foundation for developing the business case and an effective 

acquisition strategy for follow-on investments by better defining 

warfighter needs and matching them with available resources. Refining 

requirements based on proven technologies and a feasible design based on 

systems engineering are best accomplished in the concept and technology 

development phase that precedes the start of a system acquisition 

program. During this early phase, the environment is conducive to changes 

in requirements that can be accomplished more cost-effectively than after 

systems integration begins and large organizations of engineers, suppliers, 

and manufacturers are formed to prepare for the start of system 

production. 

We are making following recommendations to reduce program risk and 

increase the likelihood of more successful program outcomes by 

delivering capabilities to the warfighter when needed and within available 

resources. Specifically, 

The Secretary of Defense should direct the Global Hawk program office to 

• limit production of the Global Hawk B aircraft to the number needed 

for flight testing until the developer has demonstrated that signals 

intelligence and radar imagery subsystems can be integrated and 

perform as expected in the aircraft, and 

• update business case elements to reflect the restructured program to 

include an analysis of alternatives, a justification for investments in the 

specific quantities needed for each type of Global Hawk Bs being 

procured (signals intelligence and advanced radar imagery), and a 

revised cost estimate. 

The Secretary of Defense should direct the Navy and Air Force 

organizations responsible for the development efforts stemming from the 

Recommendations for 

Executive Action 
Page 24 GAO-06-447 Unmanned Aircraft Systems 

former J-UCAS program to not move into a weapon system acquisition 

program before 

• determining requirements and balancing them to match proven 

technologies, a feasible design based on systems engineering by the 

developer, and available financial resources; 

• developing an evolutionary and knowledge-based acquisition strategy 

that implements the intent of DOD acquisition policy; and 

• establishing strong leadership empowered to carry out the strategy that 

will work in conjunction with the other services to ensure the design 

and development continue to incorporate commonality as initiated 

under the DARPA-managed joint program. 

DOD provided us with written comments on a draft of this report. The 

comments appear in appendix II. DOD concurred with our three 

recommendations on the J-UCAS, but did not concur with our two 

recommendations on the Global Hawk. Separately, DOD provided 

technical comments, which we incorporated where appropriate. 

Regarding our recommendation to limit Global Hawk procurement, DOD 

stated that the program is managing risk and would test the signals 

intelligence sensor and advanced radar on other systems and transition 

them to Global Hawk when mature. DOD stated that our recommendation 

would stop the production line and incur significant cost and schedule 

delays. 

We continue to believe that limiting further Global Hawk B procurement 

to units needed for testing until the aircraft and its advanced technologies 

are integrated and operationally evaluated will lead to better program 

outcomes. The Global Hawk program is experiencing significant cost, 

schedule, and performance problems, and reducing procurement should 

lessen future program risks and allow more time to mature and test the 

new aircraft design and technologies before committing funds for most of 

the fleet. No Global Hawk B aircraft has completed production yet and 

first flight is not expected until November 2006. Initial operational test and 

evaluation of the basic aircraft design with only imagery intelligence 

capabilities has slipped into fiscal year 2009. According to the Air Force's 

current budget plans, more than one-half of the total Global Hawk B fleet 

will have been purchased before starting initial operational test and 

evaluation. Schedules for follow-on operational tests of the aircraft 

integrated with the advanced signals intelligence and radar technologies—

the capabilities that drove the decision to acquire the larger aircraft—have 

Agency Comments 

and Our Evaluation 
Page 25 GAO-06-447 Unmanned Aircraft Systems 

also slipped. While we support Air Force efforts to first test these new 

capabilities on surrogate systems, our concern is again that, by the time 

the Air Force tests fully integrated Global Hawk systems in an operational 

environment, most of the aircraft will already be built or on order. If 

problems are revealed during testing of the aircraft and its technologies, 

they could require costly redesign and remanufacture of items already 

produced and further delay getting these capabilities to combatant 

commanders. 

There are several other compelling reasons to limit procurement plans: 

• Projected delivery dates for the Global Hawk B continue to slip. 

Estimated delivery schedules in the fiscal year 2007 budget show that 

deliveries have slipped an average of almost 10 months since Global 

Hawk B production started in July 2004 and by an average exceeding 6 

months in the last year alone. If any further slippage occurs, 

production may be a year or more behind what the Air Force's 

strategy and financial plan was built upon. With these delays, the Air 

Force should be able to reduce near-term buys and rebalance 

subsequent procurements without materially affecting the flow of 

production. 

• Procurement through fiscal year 2006 will complete its approved lowrate initial production quantity of 19 aircraft. By law, a major weapon 

system cannot proceed beyond the low-rate quantity until initial 

operational test and evaluation has been satisfactorily completed as 

reported by the Director, Operational Test and Evaluation. Again, 

initial operational test and evaluation has been delayed until fiscal 

year 2009. In his annual report, the Director stated that low-rate 

production quantities should not be increased on the Global Hawk 

until after an adequate initial operational test and evaluation of the 

Global Hawk B aircraft and ground segments. 

• Operational assessment of the smaller Global Hawk A is not yet 

complete. Testing and flight operations have experienced engine shutdowns, communication failures, and imagery data processing 

deficiencies. These problems directly affect the Global Hawk B 

because it uses the same engine and similar communication and data 

processing systems. 

Regarding our recommendation to update the Global Hawk’s business 

case, DOD stated that the department’s current Nunn-McCurdy 

certification evaluation and program rebaselining is thorough and provides 
Page 26 GAO-06-447 Unmanned Aircraft Systems 

department leaders with the information they need to make informed 

decisions. Because the Nunn-McCurdy certification and rebaselining effort 

is ongoing, we cannot comment on whether these documents will make up 

a comprehensive business case. However, given the magnitude of the 

program’s continuing changes and challenges discussed in this report, we 

are concerned that these efforts will fall short. A business case should be 

rigorously updated to reflect significant restructurings, to justify specific 

investments in new and emerging technologies, and to match revised 

requirements to available resources. 

Our apprehension is not unfounded. In November 2004, we similarly 

recommended that DOD delay further procurement of the Global Hawk B 

until a new business case—one that reduced risk and applied a 

knowledge-based approach—was completed. DOD chose not to concur 

with this recommendation, arguing that the department was effectively 

mitigating risk. Despite DOD’s assurances, events that triggered the NunnMcCurdy review in April 2005 not only indicate that the risk mitigation 

measures were ineffective but underscore the wisdom of making a new 

business case. In addition to cost increases, schedule delays, and 

performance problems that have altered many of the program’s conditions 

and plans as they were originally envisioned, officials said they are 

rethinking Global Hawk test plans and low-rate quantities, which could 

affect the elements on which a business case is made. Our past work on 

major weapon systems acquisitions has clearly shown the value of 

preparing and maintaining a comprehensive business case to justify and 

guide investments, and the need to revisit the business case if 

circumstances substantially change, as they have on Global Hawk. 

To determine the extent to which Global Hawk and Predator acquisition 

strategies and business cases were effective in meeting warfighter 

requirements we reviewed budget and planning documents. We also 

utilized GAO’s Methodology for Assessing Risks on Major Weapon System 

Acquisition Programs to assess their acquisition strategies and business 

cases with respect to best practices criteria. The methodology is described 

from the best practices and experiences of leading commercial firms and 

successful defense acquisition programs. We interviewed DOD and 

contractor officials and obtained programmatic data and reports for the 

Global Hawk and Predator. We incorporated our recent Global Hawk and 

Predator Quick Look efforts and past GAO reports and testimony. We 

reviewed management plans, cost reports, progress briefings, and risk data 

to identify execution efforts and results to date. 

Scope and 

Methodology 
Page 27 GAO-06-447 Unmanned Aircraft Systems 

The primary comparisons made in the report are for the most part focused 

on the combined Global Hawk program and the Predator B program. 

Information on the Predator A program mainly provides a historical 

perspective and lessons learned from that older and more mature system. 

We received DOD comments questioning whether the Global Hawk and 

Predator B programs can reasonably be compared given the differences in 

time frames; Global Hawk’s system start was in March 2001, 3 years earlier 

than Predator B’s start in February 2004. 

While we agree that there may sometimes be a period of time before 

problems in a newer program become evident, we believe the two 

programs can be compared to provide valuable lessons for future 

acquisitions. First, concerns about acquisition strategy, concurrency, and 

funding profiles are not particularly dependent on time frames. Second, 

the DOD policy preference for incremental acquisitions used as criteria in 

comparing programs was in effect when both programs started. Third, the 

Global Hawk B, which comprises most of the Global Hawk program, did 

not begin production until after the start of Predator B. In a comparable 

time frame since then, the Predator B program has provided some interim 

combat capability and has production models flying and undergoing tests, 

while the first Global Hawk B is expected to make its first flight later this 

year. 

To identify what lessons can be learned and applied on the J-UCAS 

program, or its offspring, we interviewed DOD and contractor officials and 

obtained programmatic data and reports on J-UCAS. We used our 

comparisons of the Global Hawk and Predator, as well as past audit work 

on unmanned and manned systems, to identify factors conducive to 

successful programs and development of effective business cases and 

implementation strategies. We monitored the changes in J-UCAS 

leadership, priorities, and support within the department and Congress, 

including the most recent decisions by the Quadrennial Defense Review. 

We utilized also information obtained in past Quick Look and budget 

review efforts concerning J-UCAS. 

In performing our work, we obtained information and interviewed officials 

from the Global Hawk, Predator, and Joint Unmanned Combat Air Systems 

Program Offices, all at Wright Patterson Air Force Base, Ohio; Air Combat 

Command, Langley Air Force Base, Virginia; Northrop Grumman 

Integrated Systems, Rancho Bernardo and Palmdale, California; General 

Atomics Aeronautical Systems, San Diego and Palmdale, California; and 

DOD Task Force for Unmanned Systems, Office of the Secretary of 

Defense, Washington, D.C. 
Page 28 GAO-06-447 Unmanned Aircraft Systems 

We performed our review from August 2005 to February 2006 in 

accordance with generally accepted government auditing standards. 

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

Secretary of the Air Force, and the Secretary of the Navy, and interested 

congressional committees. We will also make copies available to others 

upon request. In addition, the report will be available at no charge on the 

GAO Web site at http://www.gao.gov. 

If you have any questions regarding this report, please call me at (202) 512-

4841. Contact points for our offices of Congressional Relations and Public 

Affairs are listed on the last page of this report. The following staff made 

key contributions to this report: Michael Hazard, Assistant Director, Bruce 

Fairbairn, Rae Ann Sapp, Charlie Shivers, Adam Vodraska, and Karen 

Sloan. 

Michael J. Sullivan 

Director, Acquisition and 

 Sourcing Management Issues 
Appendix I: Unmanned Aircraft Systems 

Included in This Review 

Page 29 GAO-06-447 Unmanned Aircraft Systems 

The Air Force’s Global Hawk system is a high-altitude, long-endurance 

unmanned aircraft with integrated sensors and ground stations providing 

intelligence, surveillance, and reconnaissance capabilities. After a 

successful technology demonstration, the system entered development 

and limited production in March 2001. Considered a transformational 

system, the program was restructured twice in 2002 to acquire 7 air 

vehicles similar to the original demonstrators (the Global Hawk A) and 44 

of a new, larger, and more capable model (the Global Hawk B). Seven 

Global Hawk As have been delivered to the Air Force. Global Hawk Bs are 

in production with first flight and first delivery expected in fiscal year 

2007. Demonstrators have seen combat operations in Iraq and Afghanistan 

and the first Global Hawk As recently arrived in-theater. 

The Predator began as a technology demonstration in 1994 and 

transitioned to an Air Force program in 1997. Predators have supported 

combat operations since 1995. Originally designed to provide tactical 

reconnaissance, the Predator A was modified in 2001 to employ Hellfire 

missiles, giving it a limited ground strike capability. In response to the 

Global War on Terror initiatives, the Air Force proposed a larger model 

carrying more weapons and flying higher and faster. The Predator B was 

approved as a new system development and demonstration program in 

February 2004. Funding plans at the time of our review were to procure a 

total of 232 Predators—181 A models and 63 B models—with additional 

future buys expected. Through calendar year 2005, 137 aircraft have been 

delivered, 8 Predator Bs and the rest Predator As. 

The Joint Unmanned Combat Systems (J-UCAS) program is a joint Air 

Force and Navy effort begun in October 2003 to develop and demonstrate 

the technical feasibility and operational value of a networked system of 

high-performance, weaponized unmanned aircraft. Planned missions 

include suppression of enemy air defenses, precision strike, persistent 

surveillance, and potentially others such as electronic attack as resources 

and requirements dictate. The program consolidated two formerly 

separate service efforts and was to develop and demonstrate larger, more 

capable, and interoperable aircraft to inform decisions on starting 

acquisition program(s) in fiscal year 2012. The Quadrennial Defense 

Review calls for restructuring J-UCAS into a Navy effort to develop an 

unmanned carrier-based aircraft, while the Air Force will consider J-UCAS 

technologies and accomplishments in its efforts to develop a new, landbased long-range strike capability. 

Figure 2 compares the salient performance characteristics of these 

unmanned aircraft systems. 

Appendix I: Unmanned Aircraft Systems 

Included in This Review 
Appendix I: Unmanned Aircraft Systems 

Included in This Review 

Page 30 GAO-06-447 Unmanned Aircraft Systems 

Figure 2: Performance Characteristics of Unmanned Aircraft Systems Reviewed by GAO 

65,000 ft.

350 knots

32 hrs.

1,950 lbs.

26,750 lbs.

116 ft.

44 ft.

Maximum altitude

Maximum speed

Endurance

Payload capacity

Take-off weight

Wingspan

Fuselage length

60,000 ft.

340 knots

28 hrs.

3,000 lbs.

32,250 lbs.

131 ft.

48 ft.

25,000 ft.

118 knots

24 hrs.

450 lbs.

2,250 lbs.

49 ft.

27 ft.

40,000 ft.

225 knots

16 hrs.

3,800 lbs.

10,500 lbs.

66 ft.

36 ft.

40,000 ft.

460 knots

7 hrs.

4,500 lbs.

36,500 lbs.

49 ft.

39 ft.

40,000 ft.

460 knots

9 hrs.

4,500 lbs.

46,000 lbs.

62 ft.

38 ft.

RQ-4A

Global Hawk

RQ-4B MQ-1A

Predator

MQ-9B X-45C

J-UCAS

X-47B

Sources: Northrop Grumman Corporation; General Atomics-Aeronautical Systems, Incorporated; The Boeing Company; and DOD data.
Appendix II: Comments from the Department 

of Defense 

Page 31 GAO-06-447 Unmanned Aircraft Systems 

Appendix II: Comments from the Department 

of Defense 
Appendix II: Comments from the Department 

of Defense 

Page 32 GAO-06-447 Unmanned Aircraft Systems 
Appendix II: Comments from the Department 

of Defense 

Page 33 GAO-06-447 Unmanned Aircraft Systems 
Appendix II: Comments from the Department 

of Defense 

Page 34 GAO-06-447 Unmanned Aircraft Systems 
Related GAO Products 

Page 35 GAO-06-447 Unmanned Aircraft Systems 

Unmanned Aircraft Systems: Global Hawk Cost Increase Understated in 

Nunn-McCurdy Report. GAO-06-222R. Washington, D.C.: December 15, 

2005. 

Unmanned Aircraft Systems: DOD Needs to More Effectively Promote 

Interoperability and Improve Performance Assessments. GAO-06-49. 

Washington, D.C.: December 13, 2005. 

Best Practices: Better Support of Weapon System Program Managers 

Needed to Improve Outcomes. GAO-06-110. Washington, D.C.: November 

30, 2005. 

DOD Acquisition Outcomes: A Case for Change. GAO-06-257T. 

Washington, D.C.: November 15, 2005. 

Defense Acquisitions: Assessments of Major Weapon Programs. 

GAO-05-301. Washington, D.C.: March 31, 2005. 

Unmanned Aerial Vehicles: Improved Strategic and Acquisition 

Planning Can Help Address Emerging Challenges. GAO-05-395T. 

Washington, D.C.: March 9, 2005. 

Unmanned Aerial Vehicles: Changes in Global Hawk’s Acquisition 

Strategy Are Needed to Reduce Program Risks. GAO-05-6. November 5, 

2004. 

Defense Acquisitions: Assessments of Major Weapon Programs. 

GAO-04-248. Washington, D.C.: March 31, 2004. 

Unmanned Aerial Vehicles: Major Management Issues Facing DOD’s 

Development and Fielding Efforts. GAO-04-530T. Washington, D.C.: March 

17, 2004. 

Force Structure: Improved Strategic Planning Can Enhance DOD’s 

Unmanned Aerial Vehicles Efforts. GAO-04-342. Washington, D.C.: March 

17, 2004. 

Defense Acquisitions: DOD’s Revised Policy Emphasizes Best Practices, 

but More Controls Are Needed. GAO-04-53. Washington, D.C.: November 

10, 2003. 

Related GAO Products 
Related GAO Products 

Page 36 GAO-06-447 Unmanned Aircraft Systems 

Defense Acquisitions: Matching Resources with Requirements Is Key to 

the Unmanned Combat Air Vehicle Program’s Success. GAO-03-598. 

Washington, D.C.: June 30, 2003. 

Best Practices: Capturing Design and Manufacturing Knowledge Early 

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

2002. 

Defense Acquisitions: DOD Faces Challenges in Implementing Best 

Practices. GAO-02-469T. Washington, D.C.: February 27, 2002. 

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

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

8, 2001 

Defense Acquisition: Employing Best Practices Can Shape Better 

Weapon System Decisions. GAO/T-NSIAD-00-137. Washington, D.C.: April 

26, 2000. 

Unmanned Aerial Vehicles: Progress of the Global Hawk Advanced 

Concept Technology Demonstration. GAO/NSIAD-00-78. Washington, D.C. 

April 25, 2000. 

Unmanned Aerial Vehicles: DOD’s Demonstration Approach Has 

Improved Project Outcomes. GAO/NSIAD-99-33. Washington, D.C.: August 

16, 1999. 

(120462) 
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