United States General Accounting Office

GAO Report to Congressional Committees

February 1997 C-17 GLOBEMASTER

Support of Operation

Joint Endeavor

GAO/NSIAD-97-50

GAO United States

General Accounting Office

Washington, D.C. 20548

National Security and

International Affairs Division

B-275466 

February 14, 1997

Congressional Committees

The initial use of the Air Force’s newest airlifter, the C-17 Globemaster in a

major military operation occurred during the North Atlantic Treaty

Organization (NATO) Peacekeeping Force deployment to Bosnia. At the end

of fiscal year 1996, the Department of Defense (DOD) had spent about

$20.5 billion to develop the C-17 and purchase 28 aircraft. It plans to buy a

total of 120 C-17s at an estimated cost of $43 billion. We have previously

reported on C-17 development, acquisition plans, and testing results.

Because of the significant cost of the C-17 and the continuing

congressional interest in the C-17’s performance, we determined (1) how

the C-17 was used and how well it performed during the deployment and

(2) whether deployment transportation requirements included the need for

airlift aircraft to perform any of the C-17’s expected operational

capabilities. We are addressing this report to you because it falls within

the jurisdiction of your committees and because of your interest in the

subject.

Background Initially, U.S. deployment plans in support of the NATO peacekeeping effort

(known as Operation Joint Endeavor) called for a heavy reliance on road

and rail for transporting troops and equipment into Bosnia. These early

plans assumed only minimal airlift support would be needed and that

would be provided by C-130s based in Europe. However, when the time

available to accomplish the logistics of moving troops and equipment into

Bosnia diminished and when various problems, including weather and rail

strikes limited the use of ground transportation, the U.S. deployment

shifted to heavy reliance on cargo aircraft. The C-130s in the theater were

supplemented by C-141s, C-5s, and C-17s from Air Mobility Command to

meet the increasing need for airlift within the European theater. The range

of airlift requirements for the Bosnia deployment were confined primarily

to intratheater1

 support, with no airdrop or medical evacuation

requirements, and only limited support provided from outside the

European theater.

The C-17 aircraft, which is being produced for the Air Force by the

McDonnell Douglas Corporation, is designed to airlift substantial payloads

over long ranges without refueling. The C-17 is planned to replace the

1

Intratheater refers to short distance transportation support within the European theater. Intertheater

refers to long distance, intercontinental missions.

Page 1 GAO/NSIAD-97-50 C-17 Globemaster
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C-141 transport aircraft in the current fleet and to complement the larger

but less maneuverable C-5 aircraft. In providing airlift support, the C-17 is

intended to deliver cargo and troops directly to forward airfields; fly into

small, austere airfields; land on short runways; transport outsize cargo

such as tanks; and airdrop troops and equipment.

In August 1995, the Air Force completed a 30-day reliability,

maintainability, and availability (RM&A) evaluation of the aircraft’s

compliance with contractual RM&A specifications. During this evaluation,

the C-17’s RM&A performance was assessed during both peace-and wartime

missions, including aerial refueling, equipment and personnel airdrops,

formation flying, low-level operations, and operations into small austere

airfields. Wartime missions ranged from 12.5 to 26 hours, while peacetime

missions ranged from 2 to 20 hours. In July 19962

 we reported that

unresolved questions regarding certain important C-17 capabilities still

remained after the RM&A evaluation. The Office of the Director, Operational

Test and Evaluation, reported in November 1995 that based on its

assessment of the C-17’s operational effectiveness and suitability, the C-17

is suitable for the conduct of air-land missions and effective in the airdrop

of personnel. However, the report also stated that additional testing was

necessary to fully evaluate the aircraft’s capability for the mass airdrop of

personnel, and that the C-17 was not effective or suitable for routine

aeromedical evacuation missions until certain deficiencies were corrected.

Results in Brief During Operation Joint Endeavor, the C-17 accomplished the airlift tasks

required of it, as did other airlifters such as the C-141, the C-5, and the

C-130. Primarily, the C-17 performed short-distance transportation support

within the European theater, and a limited number of long distance,

intercontinental air transport missions. In particular, the C-17 was used to

satisfy the Army’s immediate need for a high-capacity, short distance air

transport to move troops, equipment, and outsize cargo from central

Europe into the Bosnia area of operations. The C-17 performed about

26 percent of the deployment airlift missions and carried about 44 percent

of the cargo moved during the deployment. The C-17 also performed a

limited number of strategic airlift missions in which it delivered cargo

from the continental United States to final destinations in Germany,

Hungary, and Bosnia. The average cargo weight carried by airlift aircraft in

support of Operation Joint Endeavor compared to their maximum payload

capacity showed that no aircraft was over stressed. For example, no airlift

2

C-17 Aircraft: RM&A Evaluation Less Demanding Than Initially Planned (GAO/NSIAD-96-126,

July 1996)

Page 2 GAO/NSIAD-97-50 C-17 Globemaster
B-275466 

aircraft on average carried more than half its maximum payload capacity.

According to contractor reports, the C-17 achieved a mission capable3

 rate

of 86.2 percent during the December 1995 through February 1996 time

frame compared to a required rate of 81.2 percent.

Transportation needs of the Bosnia deployment did not offer the

opportunity for any airlift aircraft to perform or demonstrate several

operational roles and/or missions, which are important parts of the C-17’s

full range of operational capabilities. Consequently, the C-17 was not

required to perform many tasks which it had trouble doing, or did not do,

during operational testing. These included several tasks the Army

considers important like landing at small austere airfields on short, wet

runways; performing strategic airdrops of both troops and equipment; and

providing aeromedical evacuation capability.

C-17 Primarily

Performed an

Intratheater Airlift

Role During

Deployment

Airlift aircraft, particularly the C-17, performed a major transportation

support role during the Operation Joint Endeavor deployment, which

occurred between the December 1995 and February 1996 time frame.

According to Air Mobility Command (AMC) data,4

 the majority of

deployment airlift missions flown were intratheater support, as were the

majority of C-17 deployment missions. (See fig. 1.) Intratheater support

involved moving troops and equipment over short distances within the

European theater, such as from Germany to the initial staging base in

Hungary, or more directly into the American sector in Bosnia. There were

few intertheater deployment requirements, which would have involved

moving troops and equipment from the continental United States into the

European theater. Of the 3,827 airlift missions flown during the

deployment time frame, 2,924 or 76.4 percent were intratheater missions.

Of the 1,000 total C-17 deployment missions, 917 or 91.7 percent were

intratheater missions.

3

An aircraft is considered to be mission capable if it is capable of performing at least one of its

assigned missions. The mission capable rate shown is overall, meaning that it includes all missions

whether intertheater or intratheater.

4

We relied upon several AMC airlift information systems during the conduct of our work. To the extent

that AMC had not completed a reliability assessment of the data contained in those systems, and

because AMC representatives expressed concern about the reliability and accuracy of that data,

analyses in this report are qualified. (See Scope and Methodology section of this report for more

details.)

Page 3 GAO/NSIAD-97-50 C-17 Globemaster
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Figure 1: Breakout of Deployment Missions

Intratheater missions Other

Intra

Other

76.4%

23.6%

All deployment missions

Intra

Other

91.7%

8.3%

C-17 missions

Airlift aircraft moved about 45,369 tons of cargo and about 

18,539 passengers during the deployment. Table 1 shows the amount of

cargo and passengers carried by each type of airlift aircraft.

Table 1: Cargo and Passengers Moved

During Operation Joint Endeavor

Deployment by Airlift Aircraft Type

Type of

airlift aircraft

Number of

deployment

missions

flown

Percent of

missions

flown

Tons of

cargo

moved

Percent of

cargo moved

Number of

passengers

moved

C-5 453 12 12,048 27 5,706

C-17 1,000 26 19,892 44 5,574

C-130 1,365 36 4,901 11 2,218

C-141 987 26 8,391 18 4,815

KC-10 22 <1 137 <1 226

Totals 3,827 100 45,369 100 18,539

As this table shows, the C-17 flew about 26 percent of the total deployment

airlift missions and carried about 44 percent of total cargo and 30 percent

Page 4 GAO/NSIAD-97-50 C-17 Globemaster
B-275466 

of total passengers. In total, the C-17 carried an average cargo load of

39,784 pounds per mission compared to the specified average cargo weight

of 48,649 pounds per mission over the lifetime of the aircraft. This is based

on mission profiles in C-17 contract specifications. Overall, all types of

airlift aircraft carried average cargo weights per mission that were less

than their maximum payload capacities. Table 2 provides a comparison of

average cargo loads per aircraft type, carried during the deployment,

versus maximum aircraft payload capacity.

Table 2: Average Cargo Weight Carried

Versus Maximum Cargo Capacity

Type of airlift aircraft

Maximum

payload capacity

in pounds

Average cargo weight in

pounds per mission

December 1995 through

February 1996

C-5 261,000 53,192

C-17 160,000 39,784

C-130 50,000 7,181

C-141 90,000 17,003

KC-10 169,500 12,454

As this table shows, none of the airlift aircraft carried maximum payload

capacities during the deployment period we evaluated. The C-5 carried the

largest reported average cargo weight per mission of 53,192 pounds while

primarily performing intertheater missions, whereas the C-17 carried an

average of 39,784 pounds while primarily performing intratheater

missions. AMC representatives said that cargo weight data for C-130 aircraft

was particularly unreliable since C-130 operators do not require tracking

of total cargo weight on a per mission basis. In responding to a draft of this

report, DOD noted that cargo weight plays a critical role in airlifter

performance only in relatively rare missions when armored vehicles

and/or ammunition are being carried. Further, DOD stated that less than

maximum cargo weight does not equate to inefficient use of aircraft since

maximum cargo volume, or the maximum volume of cargo that will fit into

an airlifter, is usually reached before maximum cargo weight is reached.

DOD also stated that since most airlift aircraft cargo loads reach maximum

volume first, it would be unusual for any airplane to carry more than

50 percent of its maximum payload weight. Finally, DOD stated that AMC

tracks cargo weight since center-of-gravity information is a safety of flight

issue; however, since cargo volume is not a safety of flight issue, AMC does

not track cargo volume carried on any airframe in the fleet.

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The prime contractor for the C-17 used a variety of performance

parameters to assess C-17 performance during the deployment. DOD used

the same parameters to assess C-17 performance during RM&A evaluation

and initial operational test and evaluation. According to the contractor, the

C-17 achieved better than required performance levels for five key

maintenance and repair parameters during the December 1995 through

February 1996 time frame. In addition, the contractor reported the C-17

achieved a mission capable rate of 86.2 percent versus a requirement of

81.2 percent during the same time period.

The C-17’s overall departure reliability and logistics departure reliability

rates during the deployment also improved over those achieved during

recent RM&A evaluations, according to AMC representatives. Overall

departure reliability is the percentage of aircraft leaving no more than 

20 minutes prior to and no later than 14 minutes after the scheduled

departure time. Logistics departure reliability rate is the percentage of

aircraft achieving on time departure not counting aircraft departure delays

caused by weather. According to AMC, between December 19, 1995, and

January 17, 1996, the C-17 achieved a logistics departure reliability rate of

97.8 percent and an overall departure reliability rate of 83.9 percent. The

C-17 also performed well when moving outsize cargo, according to AMC

representatives. Outsize cargo is defined as a single item that exceeds

1,000 inches long by 117 inches wide by 105 inches high in any one

dimension and requires the use of a C-5 or C-17 aircraft (an M-1 tank, for

example). AMC representatives listed the following examples of the C-17

moving outsize cargo during the deployment: one C-17 landed at Tuzla

with a self-propelled 155-mm howitzer, a support vehicle, and trailer;

seven C-17s moved 15 Bradley fighting vehicles plus support in 1 day

during the deployment; and three C-17s moved 25 pontoon bridge sections

to Hungary.

Deployment Did Not

Include the

Opportunity for the

C-17 to Perform the

Full Range of

Operational

Capabilities

The Bosnia deployment airlift requirements did not include the need for

any airlift aircraft to perform or demonstrate several of the airlift roles and

missions which the Army considers important operational capabilities for

the C-17 in providing support for certain Army missions. The C-17 had

trouble performing, or did not perform, several of these tasks during

operational testing and the RM&A evaluation. For example, Army reports on

the C-17 RM&A evaluation and initial operational testing results have raised

questions regarding the C-17’s ability to operate on short, wet runways;

perform personnel airdrops missions; and provide aeromedical

Page 6 GAO/NSIAD-97-50 C-17 Globemaster
B-275466 

evacuation. The Bosnia deployment did not provide the opportunity for

any airlift aircraft to demonstrate these capabilities.

During initial operational testing, concerns surfaced regarding the C-17’s

ability to operate on short, wet runways. The Army defined a short austere

airfield as a 3,000-foot long runway, either paved or unpaved, for the

purpose of operational testing. Simulations have shown that, during a

landing on wet unpaved surfaces, the C-17 would slide off the end of a

3,000-foot long runway. Rather, simulations suggest that C-17 landings

with a full payload on a wet (paved or unpaved) surface would require a

5,000-foot runway. Since none of the runways used by any airlift aircraft

during the deployment were less than 7,8745

 feet, the Bosnia deployment

did not provide the opportunity to assess any airlifter’s ability to operate

on short, wet runways.

The C-17 also did not have the opportunity to demonstrate its ability to

support personnel airdrops since no airlift aircraft had to fly such missions

during the Operation Joint Endeavor deployment. The Army considers

personnel formation airdrops a logical extension of its personnel airdrop

requirement and, primarily due to safety concerns, it did not certify

personnel formation airdrops for the C-17 during operational testing.

According to DOD, the Army and the Air Force are jointly working to

address C-17 formation personnel airdrop issues.

Airlift aircraft were also not required to perform aeromedical evacuations

during the Bosnia deployment. According to the Army’s report on C-17

initial operational test results, the C-17 demonstrated the capability to

move 36 patients versus an Army requirement to move 48 patients in an

aeromedical evacuation. Further, the Army notes that initial operational

testing found a number of other deficiencies in the C-17 aircraft that make

it unsuitable for use in performing routine aeromedical evacuations. But,

according to AMC, all current C-17s will be capable of fulfilling designated

aeromedical airlift roles by June 1997. According to DOD, in August 1996,

based on the AMC Commander’s recommendation to amend the published

C-17 aeromedical evacuation requirement, the requirement was changed

from 48 to 36 patient litters. DOD notes that while the AMC Commander

cannot change the requirement, the Commander can make declarations of

capability, and the new capability for 36 litters will be reflected in an

updated C-17 Operational Requirements Document.

5

According to DOD, although the full 8,530-foot runway length at Sarajevo was available to the C-130, a

tunnel dug under the runway during previous fighting in Bosnia weakened the runway beyond

5,860 feet. For this reason, both C-141 and C-17 aircraft were restricted to using the first 5,800 feet.

Page 7 GAO/NSIAD-97-50 C-17 Globemaster
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Agency Comments DOD believes the C-17’s performance in the Bosnia deployment validates

the November 1995 Defense Acquisition Executive’s decision to procure

an additional 80 C-17s, for a total of 120 aircraft. The scope of work for

this report did not include a validation/invalidation of that decision.

However, in our report, Military Airlift: Options Exist For Meeting

Requirements While Acquiring Fewer C-17s (GAO/NSIAD-97-38, Feb. 1997), we

suggested that Congress consider funding only 100 C-17s, which would

save over $7 billion in life-cycle costs over the 120 C-17 aircraft program.

We reported that DOD can meet mission requirements with 100 C-17s by

employing various low-cost options and by extending the use of

alternatives for accomplishing the extended range brigade airdrop.

DOD also stated that it was inappropriate to include any discussion

regarding C-17 capabilities to perform short-wet runway operations,

personnel airdrops, and aeromedical evacuations in our report, since

during the deployment there were no missions requiring those capabilities.

We disagree. Our scope of work included an examination of the missions

that the C-17 performed during the deployment and a comparison of how

it was used versus its expected capabilities. A discussion of whether the

C-17 had the opportunity to perform the stated capabilities during the

deployment is appropriate to the discussion, since these are C-17

operational capabilities that have yet to be fully demonstrated. DOD also

provided suggestions for additional comments to be included in the report.

To the extent practical, those comments are reflected in the body of our

report. DOD’s written comments are included in appendix I.

Scope and

Methodology

To determine (1) how the C-17 was used during the deployment and

(2) whether the deployment required airlift aircraft to perform any of the

unique operational capabilities the C-17 is expected to perform, we

interviewed officials and obtained, reviewed, and analyzed reports and

electronic airlift transportation performance information. This information

was provided by the U.S. Transportation Command and AMC. We also

interviewed deployment airlift customers and analyzed reports and data

available from the U.S. European Command; the U.S. Army, Europe; and

the U.S. Air Forces, Europe; as well as discussed and documented their

observations concerning the performance of the C-17 from a customer

perspective.

To determine the operational capabilities required and actually performed

during the deployment, we interviewed C-17 pilots, maintainers, and

loadmasters at the 437th Air Wing, Charleston Air Force Base, South

Page 8 GAO/NSIAD-97-50 C-17 Globemaster
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Carolina; and conducted interviews and analyzed reports on C-17

deployment experience from representatives of the 621st Air Mobility

Operations Group at Travis Air Force Base, California, who comprised and

operated the Tanker Airlift Control Elements at Zagreb, Croatia, and

Taszar, Hungary. The scope of our work did not include an assessment of

the cost-effectiveness of using one airlift aircraft to provide intratheater

airlift support versus another. However, we are currently assessing DOD’s

intratheater airlift requirements and will address the cost-effectiveness

issue in that report.

To assess reported airlift activity by aircraft type during the deployment,

we analyzed data contained in AMC’s Military Airlift Integrated Reporting

System (MAIRS) and the AMC History System (AHS). AHS is a database of

airlift sorties and is intended to replace MAIRS; however, AMC was using

both systems at the time of the Joint Endeavor deployment. AMC

representatives expressed concern about data accuracy and reliability of

both databases. At the time of our review, AMC officials could not provide

us with a statistical error rate or confidence level with which they, or we,

could rely on data derived from these systems. However, AMC used this

data to support some of its C-17 performance claims.

Our assessment of those databases supports various AMC representatives’

concerns regarding data reliability and accuracy. Our review of data within

these systems identified records containing questionable information. For

example, 57 records indicated that aircraft took off but never landed, 

11 records indicated sorties had negative flying hour lengths, and 

438 records indicated that airlift aircraft flew missions into Bosnia and/or

Hungary but carried no cargo or passengers. We presented our

observations in a fact sheet to AMC officials who agreed that our analysis

highlights some problems it needs to address. Further, they indicated

these problems could be the result of data input errors, lack of proper

review of data input in the theater, or a lack of system validation. AMC

officials also said that some of our concerns may have resulted from

problems with our analysis; however, AMC will need to perform a more

detailed review of the data to make that determination. AMC officials are

aware of inaccurate data and reliability problems associated with these

systems and have had an outside contractor working to resolve them since

March 1996. AMC said that the contractor underestimated the effort

required and had revised its completion date to the end of October 1996.

However, the contractor had not completed work by the time we prepared

this report in December 1996.

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Although the accuracy of AMC’s data covering the activities of its airlift

aircraft is questionable, we attempted to obtain an accurate picture of how

the C-17 was used and how well it performed by contacting and

interviewing Air Force operational, maintenance, and loadmaster

personnel who were directly involved with operating the C-17 during the

Joint Endeavor deployment. We also interviewed AMC’s customers in the

European theater, including high-level Army and Air Force officials. In

addition to working with AMC to resolve data issues, we have drafted a

letter of inquiry for the Secretary of Defense regarding concerns we have

about the potential effect of unreliable and/or inaccurate airlift

performance and operational data. We are confident that, in general, we

have a fairly accurate picture of how the C-17 was used and how it

performed during the deployment, although AMC has not taken a formal

position on the reliability and/or accuracy of the specific data in its

databases. Since AMC had not performed a reliability assessment of these

systems, and because it is not able to provide a statistical error rate or

confidence level for data derived from these systems, all of this data must

be qualified.

We conducted our review from May to December 1996 in accordance with

generally accepted government auditing standards. We provided a draft of

this report to DOD and incorporated their comments where appropriate.

The department’s written comments are included in appendix I.

We are providing copies of this report to the appropriate House and

Senate Committees and the Secretaries of Defense, the Air Force, and the

Army. We will also provide copies to other interested parties upon request.

If you or your staff have any questions concerning this report, please call

me on (202) 512-5140. The major contributors to this report were William

C. Meredith, John G. Wiethop, and David J. Henry.

Mark E. Gebicke

Director, Military Operations

and Capabilities

Page 10 GAO/NSIAD-97-50 C-17 Globemaster
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List of Congressional Committees

The Honorable Strom Thurmond

Chairman

The Honorable Carl Levin

Ranking Minority Member

Committee on Armed Services

United States Senate

The Honorable Ted Stevens

Chairman

The Honorable Daniel K. Inouye

Ranking Minority Member

Subcommittee on Defense

Committee on Appropriations

United States Senate

The Honorable Floyd Spence

Chairman

The Honorable Ronald V. Dellums

Ranking Minority Member

Committee on National Security

House of Representatives

The Honorable C.W. Bill Young

Chairman

The Honorable John P. Murtha

Ranking Minority Member

Subcommittee on National Security

Committee on Appropriations

House of Representatives

Page 11 GAO/NSIAD-97-50 C-17 Globemaster
Appendix I 

Comments From the Department of Defense

(703151) Page 12 GAO/NSIAD-97-50 C-17 Globemaster
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