United States General Accounting Office

GAO Report to Congressional Committees

January 1995 C-17 AIRCRAFT

Cost and Performance

Issues

GAO/NSIAD-95-26

GAO United States

General Accounting Office

Washington, D.C. 20548

National Security and

International Affairs Division

B-258210 

January 26, 1995

The Honorable Strom Thurmond

Chairman

The Honorable Sam Nunn

Ranking Minority Member

Committee on Armed Services

United States Senate

The Honorable Floyd Spence

Chairman

The Honorable Ronald V. Dellums

Ranking Minority Member

Committee on National Security

House of Representatives

The fiscal year 1994 conference report on the Department of Defense’s authorization act

contains a provision calling for us to assess the C-17’s original justification and the effect of

technical problems and cost increases on the aircraft’s ability to achieve original program

requirements. This report responds to that provision and also discusses some of the

assumptions underlying the conclusions in the recent C-17 cost and operational effectiveness

analysis.

This report was prepared under the direction of Louis J. Rodrigues, Director of Systems

Development and Production Issues, who may be reached on (202) 512-4841 if you or your staff

have any questions. Major contributors are listed in appendix II.

Henry L. Hinton, Jr.

Assistant Comptroller General
Executive Summary

Purpose In recent years, there has been congressional concern about whether the

C-17 is the most cost-effective aircraft to meet the Air Force’s airlift

requirement. The Fiscal Year 1994 National Defense Authorization Act

conference report contains a provision calling for GAO to assess the C-17’s

original justification and the effect of technical problems and cost

increases on the aircraft’s ability to achieve original program

requirements. This report responds to that provision. It also discusses the

nature of the performance problems, the extent of the cost growth, and the

results of the Department of Defense’s (DOD) recent C-17 cost and

operational effectiveness analysis.

Background In 1981, DOD identified a need for additional long-range airlift and

established a fiscally constrained airlift goal of 66 million ton-miles per

day. At that time, long-range airlift capacity was about 29 million ton-miles

per day. To reach the goal, the Air Force procured 50 C-5Bs and 44 KC-10

aircraft and began developing a new airlifter, the C-17.

The Air Force originally planned to acquire 210 C-17 aircraft. However, in

April 1990, as part of DOD’s Major Aircraft Review, the Secretary of

Defense reduced the program to 120 aircraft—a sufficient number to

maintain an airlift capacity of 52 million ton-miles per day, which was

judged to be sufficient in the post-Cold War era. Through fiscal year 1995,

Congress has appropriated almost $18 billion for the C-17 program. Due to

cost, schedule, and performance concerns, the Deputy Secretary of

Defense recently reduced the program to 40 aircraft, pending a Defense

Acquisition Board review currently scheduled to occur in November 1995.

The Air Force, however, is still planning for a 120-aircraft program. This

report is intended to be used in congressional oversight of the pending

decision. The provisional 40-aircraft program is estimated to cost

$22.5 billion, an additional $4.5 billion over the amount appropriated

through fiscal year 1995.

Results in Brief The C-17 was intended to perform several unique military missions, such

as delivering cargo and troops directly to forward airfields, potentially

near the battle zone; operating routinely into small, austere airfields in an

intratheater role; airlifting outsize cargo—the largest items in the Army’s

inventory, for example, tanks—and performing airdrop missions.

However, these capabilities, on which the aircraft was originally justified,

are not likely to be used as originally intended. Meanwhile, the program’s

cost continues to increase. DOD’s recent C-17 cost and operational

Page 2 GAO/NSIAD-95-26 C-17 Aircraft
Executive Summary

effectiveness analysis, while concluding that the C-17 is the preferred

airlifter, showed that a fleet comprised of 40 C-17s and 64 commercial

freighters could meet DOD’s airlift requirements as expressed in the

Mobility Requirements Study. This alternative fleet can be procured at cost

savings of $10.7 billion or more (in constant fiscal year 1993 dollars) when

compared to a fleet of 120 C-17s.

Changes in the C-17’s intended role, the results of DOD’s C-17 cost and

operational effectiveness analysis, and continued program cost growth

lead us to conclude that a 120-aircraft C-17 program is not the most

cost-effective way to meet airlift requirements.

Principal Findings

C-17’s Original Role Has

Changed

The C-17 will not be used as initially envisioned because:

• The Air Force no longer plans to routinely operate the C-17 in an

intratheater shuttle role, largely as a result of DOD’s decision to reduce the

quantity of aircraft from 210 to 120.

• The Army has not incorporated direct delivery1 into its deployment

doctrine or mobility planning exercises and would have to fundamentally

change its deployment doctrine to use direct delivery routinely. Even if the

Army implemented a direct delivery concept, the C-17 would only rarely

be used to deliver cargo to forward airfields near the battle front, in

contrast to the original C-17 concept of operations.

• The Air Force has reported that the C-17’s capability to land on short

airfields would enable it to land on 6,400 more airfields in the free world

(less the United States) than the C-5. However, when wartime landing

requirements, including minimum runway strength, are considered, the

C-17’s wartime airfield advantage decreases from 6,400 to about 1,400

airfields.

• Outsize cargo requirements have declined in the post-Cold War world, and

DOD’s analysis shows that fewer than 120 C-17s are needed to meet current

outsize airlift requirements.

• The Army no longer plans to use the C-17’s unique low-altitude parachute

extraction capability to deliver platforms weighing up to 60,000 pounds,

and, due to airflow problems on the aircraft, the C-17 airdrop requirement

will be reduced.

1

Direct delivery involves bypassing a main operating base to land directly at another base in the theater

of operations. This base may or may not be a small, austere airfield.

Page 3 GAO/NSIAD-95-26 C-17 Aircraft
Executive Summary

Program Cost Increases

Continue

DOD’s original plan was to buy 210 aircraft for a total cost of $41.8 billion.

In December 1992, total program costs for 120 aircraft were estimated to

be $39.5 billion at a maximum production rate of 16 aircraft per year. In

January 1994, estimated program costs increased to $43 billion, in part

because the projected maximum procurement rate was reduced to 

12 aircraft per year.

In May 1994, DOD estimated that program costs would further increase to

$45.4 billion at a maximum production rate of 12 aircraft per year, due to

higher production and support costs. DOD also indicated that, if the

maximum production rate were restricted to eight aircraft per year,

program costs could increase to about $48 billion. In recent years, because

of its concern with ongoing development and production problems,

Congress has reduced funding to slow the C-17’s procurement rate and to

reduce the level of concurrency in the program.

Cost-Effective Alternatives

to the C-17

A recent C-17 cost and operational effectiveness analysis, conducted for

DOD by the Institute for Defense Analyses, compared the delivery

capability of the C-17 to alternative fleets, including a mixed fleet of 40

C-17s and 64 modified commercial freighters. That analysis concluded that

the C-17 is the preferred airlifter. However, this conclusion was based on

questionable assumptions about airfield availability, aircraft utilization

rates, and the C-17’s intratheater capability. If alternative—and, we

believe, more realistic—assumptions are made, the C-17/commercial fleet

could meet airlift requirements at cost savings of about $10.7 billion.

Matter for

Congressional

Consideration

In light of changes in the C-17’s intended role, the results of DOD’s cost and

operational effectiveness analysis, and continued program cost growth,

Congress should not support the C-17 program beyond the minimum

number needed to fulfill unique military requirements. That number has

not yet been determined, but is the subject of several ongoing studies.

Agency Comments

and GAO’s Evaluation

In commenting on a draft of this report, DOD agreed that it would be

premature to commit to buying 120 C-17s at this time. However, DOD stated

that (1) the role of the C-17 has not changed, (2) the C-17 can and will

perform routine direct delivery and intratheater missions, (3) the airfield

accessibility advantage of the C-17 over the C-5 is significant, and

(4) crediting a 120-C-17 fleet with cost savings to reflect a reduced C-130

Page 4 GAO/NSIAD-95-26 C-17 Aircraft
Executive Summary

role was appropriate and did not result in understating the potential

savings associated with mixed fleet alternatives.

GAO’s comparison of the C-17’s originally envisioned role (as discussed in

the 1986 C-17 System Operational Concept and the 1983 Airlift Master

Plan) with how the Air Force currently plans to operate it clearly shows

that a change in the C-17’s role has occurred. The C-17 was originally

intended to routinely deliver cargo directly to areas near the battle front,

but now the Air Force concept of operation says it will only rarely be used

in a direct delivery role into forward areas.

The Air Mobility Command has informed GAO that, given the reduction in

the number of C-17s from 210 to 120, it no longer intends to use the C-17

extensively for intratheater shuttle missions.

Of the 1,400 airfields that comprise the C-17’s advantage over the C-5,

DOD’s 1992 Mobility Requirements Study identified only 3 that would likely

be used in a major regional contingency.

The number of C-130s in the inventory has not been reduced as a result of

the introduction of the C-17 nor are there plans to do so. Therefore, the

C-17 should not be credited with any degree of additional cost savings to

reflect an intratheater shuttle role and a reduction in the use of the C-130.

The inclusion of cost savings in the cost and operational effectiveness

analysis increased the cost of the alternative fleets relative to the C-17.

Page 5 GAO/NSIAD-95-26 C-17 Aircraft
Contents

Executive Summary 2

Chapter 1 

Introduction

8

C-17 Expected to Modernize Airlift Fleet 8

Provisional 40-Aircraft Program Implemented 10

Objective, Scope, and Methodology 10

Chapter 2 

C-17’s Planned Role

Has Changed

12

Justification for the C-17 12

C-17’s Intended Role Has Changed 13

Conclusion 20

Agency Comments and Our Evaluation 20

Chapter 3 

Alternatives to the

C-17 Can Help Meet

Airlift Requirements

at Significantly Lower

Cost

22

C-17 COEA 22

C-17’s Program Cost Continues to Increase 24

Minimum Number of C-17s Needed to Fulfill Unique Military

Requirements Not Yet Determined

25

Conclusion 26

Matter for Congressional Consideration 26

Agency Comments and Our Evaluation 26

Appendixes Appendix I: Comments From the Department of Defense 28

Appendix II: Major Contributors to This Report 50

Figures Figure 1.1: C-17 Aircraft 9

Figure 2.1: C-17 Concept of Operations 13

Figure 2.2: Original C-17 Delivery Concept 15

Figure 2.3: Current C-17 Delivery Concept 16

Abbreviations

AMC Air Mobility Command

COEA cost and operational effectiveness analysis

DOD Department of Defense

IDA Institute for Defense Analysis

LAPES low-altitude parachute extraction system

MRS Mobility Requirements Study

MTM/D million ton-miles per day

Page 6 GAO/NSIAD-95-26 C-17 Aircraft
Page 7 GAO/NSIAD-95-26 C-17 Aircraft
Chapter 1 

Introduction

In the event of a conflict or crisis overseas, the United States must be able

to deliver the troops, equipment, and supplies necessary to meet the

threat. The Department of Defense (DOD) relies on airlift, sealift, and

prepositioned assets to accomplish this mission. Airlift, the vital

component that provides rapid mobility to combat forces, delivers Army

light forces, equipment, initial resupply and bulk ammunition, and nearly

all precision munitions and time-critical items. Airlift can also rapidly

transport troops and supplies to link up with prepositioned equipment,

thus speeding the deployment of heavier units early in a conflict.

C-17 Expected to

Modernize Airlift

Fleet

Airlift is classified as either intertheater (from one theater of operation to

another) or intratheater (operations within a theater). Intertheater airlift

services are provided by the Air Force’s Air Mobility Command (AMC),

which has a fleet of C-5, C-141, and KC-10 aircraft to carry out that

mission. AMC also relies on the Civil Reserve Air Fleet to supplement its

military airlift capacity during contingencies. The Air Combat Command is

responsible for operating C-130 aircraft, which provide intratheater airlift.

In July 1982, the Air Force contracted with McDonnell Douglas

Corporation to develop and produce the C-17, which is an air refuelable,

four-engine jet transport, designed to operate in both the intertheater and

intratheater roles (see fig. 1.1). The C-17 is currently contracted to carry a

maximum payload of 160,000 pounds 2,400 nautical miles unrefueled and

perform the full range of airlift missions, including unique military

missions such as direct delivery to forward airfields, potentially near the

battle zone; routine operations into small, austere airfields in an

intratheater role; airlift of outsize cargo such as tanks; and airdrop.

Page 8 GAO/NSIAD-95-26 C-17 Aircraft
Chapter 1 

Introduction

Figure 1.1: C-17 Aircraft

Source: McDonnell Douglas Corporation.

The Air Force originally planned to acquire 210 C-17 aircraft. However, in

April 1990, as a result of DOD’s Major Aircraft Review, the Secretary of

Defense reduced the program to 120 aircraft. The C-17 is still undergoing

test and evaluation, with the flight test program scheduled to be completed

in June 1995. DOD plans to have a fleet of 120 C-17s delivered by 2004.

Page 9 GAO/NSIAD-95-26 C-17 Aircraft
Chapter 1 

Introduction

Provisional 40-Aircraft

Program Implemented

In recent years, Congress has expressed concern with the C-17’s growing

cost and continuing technical problems. The Fiscal Year 1993 Defense

Authorization Act required DOD to conduct a special Defense Acquisition

Board review of the program. In December 1993, as a result of the review,

the Secretary of Defense announced that the program would be stopped at

40 aircraft unless McDonnell Douglas could demonstrate that program

cost, schedule, and performance warranted completing the 120 aircraft

program. As we recently testified,1 DOD has proposed lowering the C-17’s

payload/range specifications. DOD has also proposed relaxing the aircraft’s

contracted short field landing specifications to levels that the C-17 can

probably achieve. DOD plans to assess the contractor’s improvements in

November 1995, at the scheduled full-rate production decision milestone.

Through fiscal year 1995, Congress has appropriated almost $18 billion for

the C-17 program, including (1) $5.8 billion for research, development,

test, and evaluation; (2) $12 billion for procurement; and (3) $163 million

for military construction. Congress has also authorized the procurement of

32 C-17 aircraft and advance procurement funds for another 8 aircraft. As

of December 1994, 17 production C-17s had been delivered to the Air

Force.

Objective, Scope, and

Methodology

The Fiscal Year 1994 Defense Authorization Act conference report

contains a provision calling for us to assess whether (1) the original C-17

justification remains valid and (2) the C-17 can still achieve its original

program requirements, given cost increases and technical problems. This

report responds to that provision. It also discusses the nature of the

performance problems, the extent of the cost growth, and the results of

DOD’s recent C-17 cost and operational effectiveness analysis (COEA), which

was conducted by the Institute for Defense Analyses (IDA).

To determine if the C-17’s original justification has changed, we reviewed

program documents, including past and current system specifications,

operational requirements documents, concepts of operation, and Army

field manuals and doctrine. We also used our past work on the Major

Aircraft Review, Operation Desert Shield/Storm, the Mobility

Requirements Study (MRS), and the C-17 program. We interviewed officials

from the Office of the Secretary of Defense, the Joint Chiefs of Staff, Air

Force Headquarters, AMC, Army Headquarters, and the Army’s Training and

Doctrine Command.

1

Military Airlift: The C-17 Proposed Settlement and Program Update (GAO/T-NSIAD-94-172, 

Apr. 28, 1994).

Page 10 GAO/NSIAD-95-26 C-17 Aircraft
Chapter 1 

Introduction

We used information from our continuing work to monitor cost, schedule,

and performance issues related to the program at the McDonnell Douglas

plant, Long Beach, California, and C-17 developmental and operational

testing by the Air Force at Edwards Air Force Base, California. We also

reviewed a recent Defense Science Board report on the C-17 and spoke

with members of the Board’s working groups regarding the C-17’s

payload/range performance and other aspects of the program.

To determine whether cost-effective alternatives to the full C-17 program

exist, we reviewed the COEA. We also interviewed officials from IDA, the

Office of the Secretary of Defense, AMC, McDonnell Douglas Corporation,

Boeing Corporation, and Lockheed Corporation.

We conducted our review between April 1993 and December 1994 in

accordance with generally accepted government auditing standards. We

obtained DOD comments on a draft of this report, which are discussed at

the end of each of the following chapters and are presented in their

entirety in appendix I along with our detailed evaluation of them.

Page 11 GAO/NSIAD-95-26 C-17 Aircraft
Chapter 2 

C-17’s Planned Role Has Changed

The Air Force justified the C-17 in the early 1980s on the aircraft’s planned

capabilities to operate routinely in an intratheater shuttle role; perform

direct delivery missions to forward airfields, potentially in hostile areas;

and airlift substantial amounts of outsize cargo such as tanks and

helicopters. The C-17 was also intended to provide the capability to

conduct low-level parachute extractions of the Army’s heavy equipment

and to airdrop troops and equipment. However, the C-17’s envisioned role

has changed, and these capabilities will not be used as originally intended.

Justification for the

C-17

DOD’s 1981 Congressionally Mandated Mobility Study addressed the U.S.

policy objective of concurrently supporting a major North Atlantic Treaty

Organization-Warsaw Pact conflict and a lesser contingency involving a

Soviet-backed threat in the Persian Gulf region. DOD recommended

increasing U.S. airlift capacity by about 20 million ton-miles per day

(MTM/D) to 66 MTM/D—the capacity to lift the required amount of cargo and

troops to Europe and Southwest Asia to counter an imminent threat. The

1981 mobility study highlighted the need for a new airlifter that could land

on small, austere airfields; perform both intertheater and intratheater

airlift missions; and carry outsize cargo—the largest items in the Army’s

inventory. Outsize cargo includes, for example, M1 tanks, Patriot battery

radar, and Apache helicopters.

The Air Force’s 1983 Airlift Master Plan concluded that, in addition to new

C-5B and KC-10 aircraft, procuring 210 C-17s was the most cost-effective

way to reach the goal of 66 MTM/D while providing necessary military

utility. Military utility included the ability to operate from austere airfields

in an intratheater airlift role, perform direct delivery missions to forward

operating locations, carry all types of combat equipment, and airdrop

combat equipment and troops. Figure 2.1 depicts the C-17’s concept of

operations.

Page 12 GAO/NSIAD-95-26 C-17 Aircraft
Chapter 2 

C-17’s Planned Role Has Changed

Figure 2.1: C-17 Concept of Operations

U.S. Base

C-17

C-17

C-130

Typical Method of Deployment 


for Intertheater Airlifters

Main Operating Base

Direct Delivery-


Intertheater

Intratheater


Delivery

Final


Destination


Airfield

Source: Air Force.

C-17’s Intended Role

Has Changed

The C-17’s role has been modified from that envisioned in the 1983 Airlift

Master Plan. The C-17 will not routinely conduct intratheater shuttle

missions, will not routinely perform direct delivery missions, and will

rarely land near the battle front. Furthermore, the dissolution of the Soviet

threat has resulted in a reduced requirement for outsize cargo. In addition,

the number of airfields open to the C-17 but not the C-5 is much less than

the Air Force has previously stated.1

 Finally, the C-17’s unique 

60,000 pound low-altitude parachute extraction system (LAPES) capability

is not needed, and the aircraft cannot meet original airdrop requirements.

C-17 Will Not Perform

Intratheater Shuttle

Missions Routinely

The C-17’s planned intratheater capability was key to its anticipated

cost-effectiveness. Intratheater missions are needed when sealifted cargo

arrives in the theater or when deployed forces need to be repositioned

quickly. These missions are typically carried out by C-130s or ground

1

Military Airlift: Comparison of C-5 and C-17 Airfield Availability (GAO/NSIAD-94-225, July 11, 1994).

Page 13 GAO/NSIAD-95-26 C-17 Aircraft
Chapter 2 

C-17’s Planned Role Has Changed

transportation. Because the C-17 would perform the workload of the

C-130s, the Air Force’s 1983 Airlift Master Plan stated that 198 C-130s

would be retired and not replaced, a key factor in establishing the C-17’s

cost-effectiveness. Current Air Force policy, however, reflects a

substantially diminished intratheater role for the C-17. For example, AMC’s

1993 Air Mobility Master Plan does not discuss using the C-17 in an

intratheater role or retiring a significant number of C-130s.

The Air Force initially anticipated that the C-17 would routinely perform

intratheater missions during contingencies. However, as a result of the

1990 Major Aircraft Review, the Secretary of Defense reduced the number

of C-17s from 210 to 120, citing the changing strategic environment and

diminished Soviet threat. Under the current 120-aircraft program, the

intertheater airlift flow would be adversely affected if C-17s were diverted

to perform intratheater missions on a routine basis. AMC officials

acknowledge that while C-17s will provide theater commanders additional

flexibility when needed, the aircraft will not routinely perform intratheater

missions as originally planned.

Direct Delivery Role May

Not Be Used Routinely

The C-17 was also intended to offer an extended direct delivery capability

by landing at forward airfields near the battle front. However, the Air

Force’s current C-17 operational concept states that the aircraft will rarely

land near the battle front. Moreover, current Army doctrine calls into

question the extent to which the C-17’s direct delivery capability will be

used. The Army—the primary user of airlift—prefers to deploy to main

operating bases rather than directly to final destination airfields.

C-17 Will Rarely Deliver Cargo

to Forward Areas

The C-17’s operational concept has changed from one that emphasizes

direct delivery to forward airfields at the brigade rear area to one that

stresses more standard airlift operations at the corps support area. The

1986 C-17 System Operational Concept stated that “the C-17’s capability to

deliver directly to small, austere airfields close to the battle area will

reduce delivery times, reduce congestion at main operating bases, and

enhance operational flexibility by increasing the number of airfields that

can be used.” This document also stated that the C-17’s routine destination

airfields would likely be located at the brigade rear area. Figure 2.2

provides an illustrative example of this concept.

Page 14 GAO/NSIAD-95-26 C-17 Aircraft
Chapter 2 

C-17’s Planned Role Has Changed

Figure 2.2: Original C-17 Delivery Concept

Brigade 


Support Area

Brigade 


Support Area

Brigade 


Support Area

Division 


Support 


Area

Corps


Support


Area

Corps Rear Area Division Rear Area Brigade Rear Area

Forward edge of the battle area.

Source: GAO representation of Army and Air Force information.

Recently, the Air Force has downplayed the extent to which the C-17 will

fly into forward areas near the front. The 1993 C-17 Employment Concept

of Operations states that the C-17 will rarely deliver cargo to the brigade

support area. The brigade support area is typically near the boundary

between the brigade rear area and the division rear area. Figure 2.3

illustrates the current concept.

Page 15 GAO/NSIAD-95-26 C-17 Aircraft
Chapter 2 

C-17’s Planned Role Has Changed

Figure 2.3: Current C-17 Delivery Concept

Brigade Support Area

Brigade Support Area

Brigade Support Area

Division 


Support 


Area

Corps


Support


Area

The C-17 will routinely land at the corps support area.


The C-17 will occasionally land at the division support area.


The C-17 will only rarely land at the brigade support area


Forward edge of the battle area.


Corps Rear Area Division Rear Area Brigade Rear Area

Source: GAO representation of Army and Air Force information.

Page 16 GAO/NSIAD-95-26 C-17 Aircraft
Chapter 2 

C-17’s Planned Role Has Changed

According to Air Force and Army officials, the C-17 would be very unlikely

to use an airfield not protected by a corps. However, AMC officials stated

that the C-17 will provide theater commanders the flexibility to operate in

forward areas if necessary.

Army Doctrinal Change

Required to Use Direct Delivery

Routinely

The Army’s current method of deployment does not use direct delivery,

even to well-developed airfields. The Army trains and fights based on a

“mass and maneuver” strategy, with forward movements planned from

major bases in the theater of operations. Desert Shield/Storm experience

and the 1992 MRS indicate that the Army remains reluctant to use direct

delivery.

During Desert Shield/Storm, numerous well-developed airfields eventually

became accessible to military airlifters in Saudi Arabia. However, the

Army preferred to use the two main operating bases and was opposed to

sending units directly to other airfields. AMC had to convince some Army

units to use direct delivery to bypass these bases and send troops and

cargo directly to the final destination airfields on C-5s and C-141s. For

example, 3 months after the Desert Shield deployment began, the Army

was still requesting that over 75 percent of its missions go to a main

operating base.

When preparing its deployment database for the MRS, which assumed a

fleet of 80 C-17s would be available, the Army again did not make use of

direct delivery. For example, in the Southwest Asia scenario, the Army

planned to send all troops and cargo to the two main operating bases that

had been used in Desert Shield/Storm. AMC persuaded the Joint Chiefs of

Staff to add more locations to increase delivery capability.

Army, Air Force, and other DOD officials agree that doctrinal changes will

be needed if the Army is to deploy using the direct delivery concept on a

routine basis.

C-17 Can Land at Fewer

Small, Austere Airfields

Than Air Force Has

Reported

The Air Force has reported that the C-17’s capability to land on short

airfields would enable it to land at about 6,400 more airfields in the free

world (less the United States) than the C-5. However, the 6,400 figure is

overstated because it did not take into account runway strength and

included all types of airfields, ranging from concrete and asphalt to gravel,

dirt, and grass, many of which are not suitable for either aircraft. When

Page 17 GAO/NSIAD-95-26 C-17 Aircraft
Chapter 2 

C-17’s Planned Role Has Changed

wartime landing requirements,2 including minimum runway strength, are

considered, the C-17’s wartime airfield advantage decreases from 6,400 to

about 1,400 airfields. More importantly, DOD’s 1992 MRS identified only

three such airfields that would likely be used by the C-17 in the major

regional contingency scenarios. Two are located in Korea and one in Saudi

Arabia.

Outsize Cargo

Requirements Have

Decreased

The 1983 Air Force decision to buy the C-17 was based largely on the

aircraft’s ability to carry outsize cargo. In the North Atlantic Treaty

Organization-Warsaw Pact scenario examined in DOD’s 1981

Congressionally Mandated Mobility Study, 27 percent of the airlifted

equipment was outsize. The post-Cold War scenarios examined in DOD’s

recent MRS, however, require a smaller percentage of outsize cargo than

the Soviet-based scenarios. In the most lift-intensive scenario in the 1992

MRS—simultaneous deployments to Southwest Asia and Korea—about

15 percent of the cargo was outsize. Recent deployment experience also

reflects a smaller outsize cargo requirement. During Desert Shield/Storm,

only 12 percent of the airlifted cargo was outsize.

An Air Force and DOD analysis shows that fewer than 120 C-17s would be

needed, in conjunction with the existing aircraft fleet, to meet the outsize

airlift delivery requirement in the 1992 MRS. The MRS moderate risk airlift

requirement, judged acceptable by DOD, was accomplished with a fleet that

included 80 C-17s. DOD did not determine the minimum number of C-17s

that would be needed to meet the moderate risk requirement. DOD is

currently preparing a new MRS, scheduled to be completed by the end of

January 1995, that will reflect the recommendations in the Department’s

1993 Bottom-up Review. Preliminary AMC data indicate that the percentage

of outsize cargo will not change significantly from the 15 percent assumed

in the 1992 MRS.

Unique C-17 LAPES

Capability No Longer

Required

LAPES is a means of extracting equipment while an airlifter flies at low

levels. At present, the C-130 is the only aircraft capable of LAPES

operations, and it is limited to extracting 42,000 pounds of equipment. In

1981, the Army identified an “urgent need” to develop a LAPES capability up

to 60,000 pounds. According to Army officials, this capability was needed

to extract armored artillery pieces, ammunition, and towing vehicles from

2

The number of airfields on which the C-5 could land was based on a wartime runway length and width

criteria of 5,000 feet by 131 feet since Air Force officials told us this is the narrowest runway that a C-5

has actually landed on during wartime.

Page 18 GAO/NSIAD-95-26 C-17 Aircraft
Chapter 2 

C-17’s Planned Role Has Changed

the same LAPES platform, which would minimize dispersion over the drop

zone. The C-17 was intended to provide this unique capability.

In March 1994, the Army acknowledged that “LAPES has been an expensive,

unused, untrained capability and is potentially of limited battlefield use.”

The Army stated that the current C-130 42,000-pound LAPES capability

“appears to more than adequately address foreseeable Army

requirements.” The Army intends neither to maintain the material systems

and rigging required for the 60,000-pound LAPES platform nor to conduct

C-17 LAPES training. Thus, the C-17 will not be used for this mission.

However, AMC officials noted that testing of a 42,000-pound C-17 LAPES

capability is currently underway.

C-17 Cannot Meet Original

Airdrop Requirements

The ability to airdrop troops and equipment is one of DOD’s most critical

requirements. Currently, only the C-141 and C-130 aircraft are capable of

routinely performing airdrop missions.3

 The Joint Chiefs of Staff recently

revalidated the requirement for a strategic airdrop of a brigade’s worth of

troops and equipment. Because the C-130 cannot fly the long distances

required for this mission and the C-141 fleet is being retired, the C-17 is

expected to fulfill this requirement. However, the C-17 has not been able

to meet initial requirements because of airflow problems caused by its

design. As a result, the Army is lowering its airdrop requirements.

The contracted specifications call for the C-17 to airdrop 102

combat-equipped paratroopers using static line deployed parachutes,

preceded by at least 8, 500-pound equipment bundles, within 55 seconds.

The bundles are to be dropped out of the cargo ramp door while the

paratroopers jump from the two troop doors on the aircraft’s sides. The

Army considers combination drops critical to early entry lethality and

survivability on the battlefield. However, testing has shown that the C-17

has severe airflow problems when the side troop doors and the rear cargo

door and ramp are open.

In March 1994, the Army notified AMC that, due to the C-17’s airflow

problems, it had revised its airdrop requirement in terms of “desired” and

“required” capabilities. The Army’s new desired objective for the

combination airdrop is to drop 102 paratroopers and 8 bundles in 

70 seconds. The required capability is to drop 102 paratroopers and 

2 bundles in 55 seconds. However, AMC officials told us that this is an

3

While the C-5 is capable of airdropping equipment, the Air Force does not routinely use the aircraft in

this role.

Page 19 GAO/NSIAD-95-26 C-17 Aircraft
Chapter 2 

C-17’s Planned Role Has Changed

unrealistic requirement because 102 paratroopers cannot exit the C-17

within this time frame. Accordingly, AMC plans to reduce the C-17 airdrop

requirement.

Another specification requires airdropping 40 containerized delivery

system bundles, weighing 2,350 pounds each. However, the C-17 has been

restricted to dropping only 30 bundles because of safety concerns. The

C-17 program office is making design changes to eliminate this safety

hazard and enable the C-17 to drop 40 bundles.

Conclusion The C-17’s anticipated role has changed and the aircraft will not be used as

originally envisioned. The C-17 was justified on the basis of its unique

capability to routinely deliver the full range of Army combat equipment to

locations inaccessible to other strategic airlifters. The C-17 is not likely to

conduct routine intratheater and direct delivery missions as planned, and

it is no longer expected to operate into forward airfields near the battle

front. Furthermore, the number of airfields in the free world open to the

C-17, but not the C-5, is significantly less than the Air Force claimed in

justifying the C-17. While the C-17 is capable of carrying outsize cargo, a

DOD analysis indicates that a fleet of 120 C-17s may not be necessary to

fulfill outsize delivery requirements. Finally, one of the aircraft’s unique

capabilities—using LAPES to deliver a 60,000-pound platform—will not be

used, and its airdrop capability does not meet the Army’s original

requirements. The aircraft is likely to operate primarily in a routine

intertheater airlift role.

Agency Comments

and Our Evaluation

DOD’s position in commenting on a draft of this report is that (1) the role of

the C-17 has not changed, (2) the C-17 can and will perform routine direct

delivery and intratheater shuttle missions, and (3) the airfield accessibility

advantage of the C-17 over the C-5 is significant.

A comparison of the C-17’s envisioned role as discussed in the 1986 C-17

System Operational Concept, the 1983 Airlift Master Plan, the 1993 C-17

Employment Concept of Operations, and the 1993 Air Mobility Master Plan

shows that the role of the C-17 has clearly changed. For example, the Air

Force no longer plans to use the C-17 to routinely conduct intratheater

shuttle missions. Further, while direct delivery is still a part of the concept

for the C-17, the C-17’s operational concept has changed from one that

emphasized direct delivery to forward airfields near the battle front to one

that emphasizes more standard airlift operations at or near a main

Page 20 GAO/NSIAD-95-26 C-17 Aircraft
Chapter 2 

C-17’s Planned Role Has Changed

operating base. The Army is changing its doctrine to incorporate the use of

direct delivery, but these doctrinal changes do not call for routine direct

delivery to forward airfields near the battle front.

Although the C-17 can land on more airfields than the C-5, the C-17’s

airfield advantage is significantly less than the 6,400 airfields originally

claimed, and the 1992 MRS identified only three small austere airfields that

would likely be used by the C-17 in major regional contingencies.

Page 21 GAO/NSIAD-95-26 C-17 Aircraft
Chapter 3 

Alternatives to the C-17 Can Help Meet

Airlift Requirements at Significantly Lower

Cost

DOD’s COEA showed that the C-17 is the preferred military airlifter because,

when considering delivery of outsize cargo, the C-17 retains its throughput

ability better than the C-5 if (1) airfield constraints are encountered and

(2) the C-17’s planned utilization rate (higher than the C-5’s experienced

rate) is achieved. However, the COEA also showed that alternative airlift

fleets, such as a combination of 40 C-17s and 64 modified commercial

freighters, can meet airlift requirements at a significantly lower cost if

alternative—in our opinion, more reasonable—assumptions are made. In

addition, C-17 program costs have continued to increase, and potential

savings from adopting an alternative to the 120-aircraft fleet could

approach $4 billion more than the $10.7 billion (in constant fiscal year

1993 dollars) we identified in our earlier report.1

C-17 COEA DOD’s COEA examined alternatives to the full C-17 program, including

(1) restarting the C-5 line, (2) extending the service life of the C-141, and

(3) procuring new commercial freighter aircraft. The capability of Boeing

747 freighters was assessed to determine how commercial aircraft would

contribute to airlift missions.2

 The COEA’s conclusion was that an airlift

fleet with 120 C-17s was the preferred choice to meet the requirements set

forth in the 1992 MRS, despite the fact that it was more expensive than a

fleet comprised of C-17s and modified commercial freighters. This

conclusion was based on three major assumptions:

• Airfield availability for airlift use would be extremely constrained.

• The C-17 would achieve a 15.2-hour per day utilization rate while

commercial freighters would achieve only a 12.5-hour per day rate.

• The C-17 would be used routinely in place of the C-130 to accomplish

intratheater delivery, so C-130 operating and support costs should be

added to non-C-17 alternatives.

Our review indicated that alternative assumptions pertaining to airfield

availability, utilization rates, and intratheater capability are more realistic.

Adjusting for these assumptions would result in the C-17 fleet being less

capable and a mixed C-17/commercial fleet being more capable and more

cost-effective than the COEA’s conclusions indicate.

1

Airlift Requirements: Commercial Freighters Can Help Meet Requirements at Greatly Reduced Cost

(GAO/NSIAD-94-209, July 11, 1994).

2

To accommodate the Army’s new 2.5- and 5-ton trucks, commercial freighters’ floors would need to

be strengthened and the side doors would need to be widened or the trucks would have to be fitted

with collapsible cab tops. The COEA reflects the estimated cost and performance of these

modifications.

Page 22 GAO/NSIAD-95-26 C-17 Aircraft
Chapter 3 

Alternatives to the C-17 Can Help Meet

Airlift Requirements at Significantly Lower

Cost

Airfield Constraints Affect

Fleet Capability

The COEA was based on the threat scenario portrayed in the 1992 MRS,

which postulated that an aggressive enemy was moving directly into Saudi

Arabia. Based on this threat, several airfield assumptions were examined.

The COEA showed that the C-17 had a better delivery capability for outsize

cargo than the mixed C-17/commercial aircraft fleet when airfield

availability was extremely limited. Under the assumption that airlift

deliveries would be equivalent to the first 45 days of Desert Shield, when

only one major airlift airfield would be available, the C-17 fleet could meet

the MRS delivery requirement, but the mixed fleet could not. However,

under the airfield assumptions used in the MRS Southwest Asia scenario, in

which more airlift airfields were assumed to be available, the COEA showed

that the mixed fleet of 40 C-17s and 64 747s could deliver the required

amount of cargo. This mixed fleet would cost about $6 billion less than the

fleet of 120 C-17s.

During the first 45 days of Desert Shield, airfield availability was limited to

only one major airlift base, due primarily to the Saudi Arabian

government’s reluctance to allow U.S. access to multiple airfields and the

U.S. Army’s preference for deploying to only major operating bases. In

Desert Shield/Storm, Iraqi troops became entrenched shortly after the

invasion of Kuwait and did not invade Saudi Arabia. We believe that, given

the threat scenario on which the COEA was based, the MRS assumption that

the Saudi government would open additional airlift airfields is more

realistic than the airfield assumption based on early Desert Shield

experience. Under the MRS airfield assumption, the mixed C-17/commercial

fleet meets the airlift requirement.

C-17’s Cost-Effectiveness

Depends on High

Utilization Rate

The COEA indicated that the C-17 would perform better than mixed fleets if

a 15.2-hour per day utilization rate were assumed for the C-17. An aircraft’s

utilization rate is the planned average daily flying hours per aircraft for the

entire fleet and is based on numerous elements, such as mission capable

rate, number of aircrews per aircraft, and availability of spares. The COEA

showed that, based on a 15.2-hour utilization rate for the C-17 and a 12.5

rate for the 747, both alternatives would meet the stated airlift

requirement. The fleet of 120 C-17s could deliver more outsize cargo than

the mixed fleet but would cost $6 billion more. If the 747’s utilization rate

is increased to 15.2, a rate AMC officials acknowledge is feasible, the results

show a significant increase in the mixed fleet’s ability to deliver outsize

and oversize cargo.3

3

Oversize cargo includes trucks, Bradley vehicles, High Mobility Multi-purpose Wheeled Vehicles, and

self-propelled howitzers.

Page 23 GAO/NSIAD-95-26 C-17 Aircraft
Chapter 3 

Alternatives to the C-17 Can Help Meet

Airlift Requirements at Significantly Lower

Cost

The C-17’s 15.2-hour utilization rate is undemonstrated. To sustain this

rate, the C-17 must demonstrate a mission capable rate of 90 percent, and

the Air Force must sufficiently fund C-17 spares and aircrews. The level of

war reserve spares for airlift aircraft has historically been less than

required to sustain projected wartime utilization rates.4

 Air Force officials

told us they believe that the spares level for the C-17 will be fully funded,

in part, because spares funding has recently been made a higher priority.

The Air Force also plans to maintain a higher aircrew to aircraft ratio for

the C-17 than for other strategic airlifters. The relatively higher C-17

aircrew ratio contributes to its ability to maintain a higher utilization rate.

COEA Underestimates

Potential Savings

Associated With Mixed

Fleet Alternative

Because the C-17 was designed to deliver cargo to small, forward airfields

typically used by the C-130, the COEA assumed that the alternative with

only 40 C-17s would need 80 additional C-130s to provide about the same

intratheater movement capability as the fleet of 120 C-17s. Thus, the

life-cycle cost of the mixed fleet alternative was increased by $4.7 billion

over 25 years (in constant fiscal year 1993 dollars). However, as discussed

in chapter 2, the C-17’s planned intratheater role has been largely limited

and the Air Force does not plan to replace C-130s with C-17s for

intratheater missions. Therefore, it was inappropriate to assume the mixed

fleet alternative should include this added $4.7 billion. If this cost is

subtracted from the mixed fleet, the cost of a fleet of 120 C-17s increases

from about $6 billion to about $10.7 billion more than the mixed fleet

alternative.

C-17’s Program Cost

Continues to Increase

In its May 1994 paper, “Department of Defense Airlift Acquisition

Strategy,” DOD included average cost figures that indicate that C-17

program cost estimates continue to increase. In December 1992, total

program costs were estimated to be $39.5 billion (in then-year dollars)5

 at

a maximum rate of 16 aircraft per year. In January 1994, the C-17 program

director estimated that total program costs would increase to $43 billion

because of a reduced procurement rate of 12 aircraft per year and

increased estimates for production and support costs.

DOD’s paper indicated that, at a maximum production rate of 12 aircraft per

year, total program costs would be $45.4 billion. This increase is

attributable to increased production and support costs and the cost of a

4

Military Airlift: Peacetime Use of War Reserve Spares Reduces Wartime Capabilities

(GAO/NSIAD-90-186, June 25, 1990).

5

Then-year dollars include estimates of future year inflation.

Page 24 GAO/NSIAD-95-26 C-17 Aircraft
Chapter 3 

Alternatives to the C-17 Can Help Meet

Airlift Requirements at Significantly Lower

Cost

recently approved business settlement between DOD and McDonnell

Douglas.6

 If the maximum procurement rate were reduced to eight aircraft

per year, DOD’s paper estimated that total program costs would increase

another $2.6 billion, to about $48 billion.7

 In recent years, due to ongoing

development and production problems, Congress has reduced funding to

slow the C-17’s production rate to reduce the level of concurrency in the

program. While the Air Force’s desired procurement rate may eventually

be achieved, the program has been significantly more stretched out than

originally planned.

The C-17 procurement cost estimates reported in DOD’s paper are

significantly higher than those in the C-17 COEA. DOD’s paper indicates that

estimated procurement costs have increased by $2.8 billion to $4 billion

(in constant fiscal year 1993 dollars) since the C-17 COEA. Consequently,

the potential savings from adopting an alternative to the 120-aircraft fleet

would be significantly greater than the $10.7 billion we previously

reported. While estimating the exact amount of savings would be very

difficult because of the many variables involved, we believe the increase in

savings could approach $4 billion. However, this estimate does not take

into account changes that may have occurred in the estimated costs of

modified commercial aircraft.

Minimum Number of

C-17s Needed to

Fulfill Unique Military

Requirements Not Yet

Determined

Determining whether a mixed fleet is a viable alternative to a 120-aircraft

C-17 program depends on the fleet’s capability to fulfill certain unique

military requirements such as direct delivery to forward airfields, routine

operations into small, austere airfields in an intratheater role, airlift of

outsize cargo, and airdrop. The COEA was not intended to address this issue

in detail. DOD has several studies underway, scheduled to be completed

before the November 1995 Defense Acquisition Board decision on C-17

full-rate production, that will assess the capability of various fleet mixes

and identify the minimum number of C-17s needed to fulfill unique military

airlift requirements. As currently planned, nondevelopmental airlift

aircraft source selection and quantity will depend on the C-17 full-rate

production decision. The Defense Acquisition Board will consider several

factors in deciding whether to continue the C-17 program, including C-17

flight test and reliability results, contractor performance, and the findings

of the Air Force’s airlift fleet mix study.

6

Military Airlift: C-17 Settlement Is Not a Good Deal (GAO/NSIAD-94-141, Apr. 15, 1994).

7

These higher program cost estimates do not include a number of contractor cost reduction proposals

that are now undergoing technical evaluation.

Page 25 GAO/NSIAD-95-26 C-17 Aircraft
Chapter 3 

Alternatives to the C-17 Can Help Meet

Airlift Requirements at Significantly Lower

Cost

Conclusion Serious concerns about the C-17’s cost-effectiveness have prompted

Congress to direct DOD to explore alternatives to the full C-17 program.

The COEA identified less costly alternatives that could meet airlift

requirements and save billions of dollars. In addition, the C-17’s program

cost continues to increase. Therefore, the savings associated with a mixed

fleet of C-17s and commercial freighters could be significantly greater than

the COEA reported.

Matter for

Congressional

Consideration

In light of changes in the C-17’s intended role, its less than anticipated

performance, the results of DOD’s COEA, and continued program cost

growth, we continue to believe that Congress should not support the C-17

program beyond the minimum number needed to fulfill unique military

requirements. That number has not yet been determined but is the subject

of several ongoing studies.

Agency Comments

and Our Evaluation

In commenting on a draft of our report, DOD stated that (1) a direct

invasion of Saudi Arabia would still likely result in extremely constrained

theater airfield availability in contrast to that reflected in the 1992 MRS,

(2) two C-17s flew missions to Kuwait and demonstrated higher utilization

rates than required, and (3) its COEA estimate of potential savings

associated with the mixed fleet alternatives was not understated.

While the precise extent of airfield availability in any future contingency is

unknown, the MRS threat suggests that more airfields will be available than

was the case during Desert Shield, when allied forces had the advantage of

a 5-month deployment period. We believe that using the Desert Shield-type

airfield situation juxtaposed against an MRS threat gives the C-17 an

inappropriate advantage over alternative airlifters. In our opinion, a more

valid basis on which to compare the C-17 to alternative airlift fleets is the

COEA’s examination of the MRS airfield availability assumption.

The recent missions to Kuwait are not an adequate basis for establishing

the appropriate sustainable utilization rate because these missions were of

extremely limited duration. DOD has not yet determined how to extrapolate

an inherent utilization rate from the results of the planned July 1995

reliability, maintainability, and availability evaluation. Our position

remains that the projected C-17 utilization rate of 15.2 is, as yet,

undemonstrated and that comparing this rate to a 12.5-hour utilization rate

for commercial airlifters that have demonstrated higher utilization rates

inappropriately favored the C-17 in the COEA.

Page 26 GAO/NSIAD-95-26 C-17 Aircraft
Chapter 3 

Alternatives to the C-17 Can Help Meet

Airlift Requirements at Significantly Lower

Cost

DOD’s position that the C-17’s intratheater role is unchanged from that

depicted in the 1983 Airlift Master Plan, despite an almost 50-percent

reduction in the number of aircraft, is untenable. DOD’s position also

contradicts the comments of Office of the Secretary of Defense and AMC

officials on our July 1994 report on the COEA, as well as the comments of

AMC officials on this report. These officials acknowledged that the C-17’s

intratheater shuttle role has been substantially diminished in the wake of

the reduction from 210 to 120 aircraft. Moreover, they concurred with our

finding that the COEA should not have assumed a cost saving to the C-17 to

account for this intratheater role.

Page 27 GAO/NSIAD-95-26 C-17 Aircraft
Appendix I 

Comments From the Department of Defense

Note: GAO comments

supplementing those in the

report text appear at the

end of this appendix.

See comment 1.

Page 28 GAO/NSIAD-95-26 C-17 Aircraft
Appendix I 

Comments From the Department of Defense

Now on pp. 2-3 and 9-10.

Page 29 GAO/NSIAD-95-26 C-17 Aircraft
Appendix I 

Comments From the Department of Defense

Now on pp. 2-3 and

12-17.

See comment 2.

See comment 3.

Page 30 GAO/NSIAD-95-26 C-17 Aircraft
Appendix I 

Comments From the Department of Defense

See comment 4.

See comment 5.

Page 31 GAO/NSIAD-95-26 C-17 Aircraft
Appendix I 

Comments From the Department of Defense

See comment 6.

See comment 7.

Now on pp. 3 and 14-17.

Page 32 GAO/NSIAD-95-26 C-17 Aircraft
Appendix I 

Comments From the Department of Defense

See comment 8.

Page 33 GAO/NSIAD-95-26 C-17 Aircraft
Appendix I 

Comments From the Department of Defense

See comment 9.

Page 34 GAO/NSIAD-95-26 C-17 Aircraft
Appendix I 

Comments From the Department of Defense

Now on pp. 3 and 17-18.

See comment 10.

Page 35 GAO/NSIAD-95-26 C-17 Aircraft
Appendix I 

Comments From the Department of Defense

See comment 11.

Page 36 GAO/NSIAD-95-26 C-17 Aircraft
Appendix I 

Comments From the Department of Defense

See comment 12.

Now on pp. 3 and 19-20.

See comment 13.

Page 37 GAO/NSIAD-95-26 C-17 Aircraft
Appendix I 

Comments From the Department of Defense

See comment 14.

Page 38 GAO/NSIAD-95-26 C-17 Aircraft
Appendix I 

Comments From the Department of Defense

Now on pp. 4 and 22-23.

See comment 15.

See comment 16.

Page 39 GAO/NSIAD-95-26 C-17 Aircraft
Appendix I 

Comments From the Department of Defense

Now on pp. 22-23.

See comment 17.

Page 40 GAO/NSIAD-95-26 C-17 Aircraft
Appendix I 

Comments From the Department of Defense

See comment 18.

Now on p. 24.

See comment 19.

Page 41 GAO/NSIAD-95-26 C-17 Aircraft
Appendix I 

Comments From the Department of Defense

See comment 20.

Now on pp. 4, 22, 

and 24-25.

See comment 21.

Page 42 GAO/NSIAD-95-26 C-17 Aircraft
Appendix I 

Comments From the Department of Defense

Now on pp. 4 and 25.

Now on pp. 4 and 26.

Page 43 GAO/NSIAD-95-26 C-17 Aircraft
Appendix I 

Comments From the Department of Defense

Page 44 GAO/NSIAD-95-26 C-17 Aircraft
Appendix I 

Comments From the Department of Defense

GAO Comments The following are GAO’s comments on the Department of Defense’s (DOD)

letter dated November 18, 1994.

1. Our response to each of these specific issues is set forth in the

following notes, which are annotated to DOD’s enclosure.

2. A comparison of the C-17’s envisioned role with how the Air Force

currently plans to operate it clearly shows that it will not be used as

originally intended—that is, the C-17 will not routinely conduct

intratheater shuttle missions and will rarely land at the brigade rear area.

DOD’s position is based on the belief that the difference between “routine”

and “rarely” is insignificant.

The basis for DOD’s statement that more, not fewer, C-17s are needed,

when DOD has yet to determine the minimum number of C-17s needed to

meet military-unique airlift requirements, is unclear.

3. Contrary to DOD’s assertion, we do not state that DOD has deleted

intratheater shuttle missions from the requirements for the C-17. Rather,

we state that the C-17 will not routinely perform intratheater missions as

originally planned. In commenting on our 1994 report (Airlift

Requirements: Commercial Freighters Can Help Meet Requirements At

Greatly Reduced Cost), Office of the Secretary of Defense and Air Mobility

Command (AMC) officials acknowledged that the C-17’s intratheater airlift

role had been substantially diminished.

4. DOD suggests that it is planning to procure the C-17, in part, to carry

out humanitarian missions. This rationale needs to be re-examined in light

of the growing cost of the aircraft. Other airlifters can accomplish these

missions at a substantially lower cost.

5. Our report does not state or imply that outsize airlift requirements

involve only percentages of overall cargo weight. Our findings are based,

in part, on AMC’s analysis for the 1992 Mobility Requirements Study (MRS),

which included all types of cargo and which was based on the MRS

time-phased force deployment data. This analysis showed that about 

80 C-17s, along with the other airlifters in the fleet, could meet DOD’s

delivery requirements. A preliminary analysis by AMC indicates that the

outsize cargo requirements in the MRS Bottom-Up Review Update will not

substantially increase from those used in the 1992 MRS. Therefore, outsize

cargo capabilities cannot be considered a basis on which to procure 

120 C-17s.

Page 45 GAO/NSIAD-95-26 C-17 Aircraft
Appendix I 

Comments From the Department of Defense

6. The ability to carry outsize cargo was one of the original capabilities

on which the C-17 was justified. Our report does not present this capability

as the sole justification for the aircraft.

7. We asked for documentation to support this statement. However, the

documentation was not provided to us. We subsequently contacted an

official from the Institute for Defense Analyses who told us that, of two

airlift models used for the cost and operational effectiveness analysis

(COEA), one accounted for the inability of commercial aircraft to carry all

oversize equipment, while the other model did not have the ability to

adjust for item configuration. Moreover, DOD has not provided us with

evidence that the oversize cargo issue would have any significant effect on

the COEA’s outcome.

8. While direct delivery has always been included as a part of the C-17’s

operational concept, we found that the Army had not incorporated direct

delivery into its doctrine. DOD’s comments do not dispute this finding.

9. The C-17’s operational concept has changed from one that emphasized

direct delivery to forward airfields at the brigade rear area to one that

stresses more standard airlift operations at the corps rear area. This

finding is supported by a comparison of original and current C-17

operational documents. As DOD states, the 1993 C-17 Concept of

Operations asserts that the C-17 will rarely direct deliver supplies to the

brigade support areas. This is in direct contrast to the 1986 System

Operational Concept, which states that the C-17 will routinely land at the

brigade rear area, which is closer than the brigade support area to the

forward edge of the battle area. (Emphasis added.)

10. DOD acknowledges that the C-17 can only land on approximately

1,400 more runways than the C-5, not the 6,400 airfields it previously had

asserted. However, even this airfield advantage should be viewed in the

context of major regional contingency scenarios and the fact that the 1992

MRS only identified three small austere airfields that would likely be used

by the C-17.

11. We have seen no evidence that the reduction in the number of C-5s

from 109 to 104 will have a significant impact on the C-17’s cargo-carrying

requirements. Furthermore, our report discusses several of the

justifications for the C-17, not outsize cargo only.

Page 46 GAO/NSIAD-95-26 C-17 Aircraft
Appendix I 

Comments From the Department of Defense

12. While the decreased Army emphasis on low-altitude parachute

extraction system (LAPES) is not unique to the C-17, it eliminates one of the

C-17-unique missions—the 60,000-pound LAPES capability.

13. The ability to airdrop equipment bundles and personnel

simultaneously is a key military requirement. Joint Chiefs of Staff and

Army officials repeatedly emphasized its importance to us during our

review. According to AMC officials, the Army’s current requirement is not

achievable and this C-17 requirement will be reduced.

14. Containerized delivery system testing is still ongoing and no final

conclusion can be made at this time.

15. Desert Shield and Operation Vigilant Warrior were significantly

different than the MRS major regional contingency scenario, which

postulates that an aggressive enemy is attempting to invade Saudi Arabia.

In the 1992 MRS, DOD assumed that more airfields would be available for

airlift operations than was the case during Desert Shield. This assumption

was based specifically on the nature of the MRS threat. The COEA’s

conclusion that the C-17 is the preferred airlifter was based on an

assumption that airfield availability in the MRS scenario would be

extremely constrained—to the point where only one major airlift airfield

was available—as was the case during the first 6 weeks of Desert Shield.

This assumption gave the C-17 an advantage over the other airlifters

because of its projected ability to use available space more efficiently than

a C-5 or a 747.

In light of the imminent threat to Saudi Arabia assumed in the MRS

scenario, we believe a more equitable assumption is the COEA’s alternative

case, which uses the MRS airfield availability assumption, rather than

juxtaposing a Desert Shield-type airfield assumption onto an MRS threat.

In our report on the 1992 MRS, we pointed out that DOD assumed that

numerous airfields would be available without determining the effect of a

range of airfield availability within the theater of operations. We did not

assert that a Desert Shield-type situation was necessarily likely to occur.

DOD’s response to our report was that, given the aggressive threat assumed

in the MRS, more airfields were likely to be available for airlift operations

than was the case during Desert Shield. As the COEA shows, various

degrees of airfield availability have a significant effect on airlift deliveries.

DOD, Air Force, and AMC officials agree that airfield availability for any

future scenario is an unknown. Therefore, choosing the Desert Shield

Page 47 GAO/NSIAD-95-26 C-17 Aircraft
Appendix I 

Comments From the Department of Defense

airfield assumption as the likely case in an MRS major regional contingency

is, in our opinion, not well grounded.

16. Our statement regarding the COEA’s conclusion on airfield availability

was correct as stated. The COEA defines “moderate” airfield constraints as

the availability of the first 6 weeks of Desert Shield, which we consider

extremely constrained. We believe the word “moderate” in this instance is

misleading. The availability of only one major airlift airfield represents in

our view an extremely constrained availability; to have anything less

would be to have no major airlift airfield availability.

17. The COEA’s conclusion that the C-17 is the preferred airlifter was

based, in part, on an assumption that the C-17 would attain a projected

utilization rate that exceeds that of any other airlifter, while the other

airlifters in the study were held to demonstrated or, in the case of

commercial airlifters, lower than demonstrated rates. The performance of

two C-17s on the recent Kuwait mission does not support the use of a

sustained 15.2-hour utilization rate in a COEA because that mission was

limited in scope. In addition, even if the C-17 attains a high utilization rate

during the July 1995 reliability, maintainability, and availability evaluation,

DOD has not yet determined how the evaluation results will be extrapolated

analytically to justify the 15.2-hour rate for a sustained period of time.

Therefore, we continue to believe that, for purposes of a COEA, comparable

utilization rates for the C-17 and the 747 would be a more legitimate basis

for comparison.

The COEA found that, even under airfield constraints reflecting the first 

6 weeks of Desert Shield, the C-17 fleet at a 12.5-hour utilization rate did

not meet the MRS requirement.

18. As DOD’s comment indicates, a comparison of ground times between

the C-17 and modified commercial aircraft has not yet been made. Once

the comparison has been accomplished, DOD should know what impact

loading and unloading of various aircraft will have on utilization rates.

19. DOD’s position contradicts comments provided by officials from the

Office of the Secretary of Defense and AMC on our recent report, Airlift

Requirements: Commercial Freighters Can Help Meet Requirements at

Greatly Reduced Cost, and AMC officials’ comments on this report. Those

officials acknowledged that, due primarily to the reduction in the number

of aircraft from 210 to 120, the C-17 is not likely to operate routinely in an

intratheater shuttle role as originally envisioned. DOD’s position also

Page 48 GAO/NSIAD-95-26 C-17 Aircraft
Appendix I 

Comments From the Department of Defense

contradicts AMC’s explicit intention, as reflected in the 1993 Air Mobility

Master Plan, not to use the C-17 for extensive intratheater shuttle

missions.

20. In its cover letter, DOD indicated that the COEA had not underestimated

potential savings associated with mixed fleet alternatives, but here DOD

indicates that the savings were underestimated by $2.8 billion, not by the

$4.7 billion as we had estimated. These two statements appear

inconsistent.

DOD concluded that C-130 operating and support costs must be borne while

C-130s are substituted for C-17s until all 120 C-17s are procured. This

conclusion was based on the assumption that the C-17 would perform

routine intratheater missions in the place of C-130s. As discussed above,

AMC no longer intends to use the C-17 extensively for intratheater shuttle

missions. The 1993 Air Mobility Master Plan makes no mention of the

C-17’s intratheater role. The number of C-130s in the inventory has not

been reduced as a result of the introduction of the C-17 nor are there plans

to do so. DOD officials have not provided any evidence that C-17s will

replace C-130s for intratheater missions. Therefore, the C-17 should not be

credited with any degree of additional cost savings to reflect such a role.

21. We have modified the report to acknowledge that nondevelopmental

airlift aircraft costs used in the COEA were only estimates and may have

changed since that time.

Page 49 GAO/NSIAD-95-26 C-17 Aircraft
Appendix II 

Major Contributors to This Report

National Security and

International Affairs

Division, Washington,

D.C.

Thomas J. Denomme

James A. Elgas

Michele Mackin

Steve Martinez

Kansas City Regional

Office

Richard E. Burrell

Karen A. Rieger

Los Angeles Regional

Office

Noel J. Lance

Dorian R. Dunbar

Carlos M. Garcia

(707086) Page 50 GAO/NSIAD-95-26 C-17 Aircraft
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