United States General Accounting Office

GAO Report to the Chairman, Subcommittee

on Government Management,

Information, and Technology, Committee

on Government Reform and Oversight

House of Representatives

June 1996 OPERATIONAL

SUPPORT AIRLIFT

Analysis of Joint Staff

Estimate of Military

Wartime Requirements

G O A

years

1921 - 1996

GAO/NSIAD-96-157

GAO United States

General Accounting Office

Washington, D.C. 20548

National Security and

International Affairs Division

B-271915 

June 21, 1996

The Honorable Stephen Horn

Chairman, Subcommittee on Government Management, 

 Information, and Technology

Committee on Government Reform and Oversight

House of Representatives

Dear Mr. Chairman:

In December 1995, we testified1

 that the Joint Chiefs of Staff had studied2

wartime requirements for Operational Support Airlift (OSA) across the

Department of Defense (DOD). OSA aircraft are used to meet short notice,

generally smaller cargo and passenger requirements that cannot be met by

regularly scheduled tactical resupply aircraft. The Joint Staff’s study found

that the joint wartime requirement for OSA is 391 aircraft, or about 100 less

than the fleet that existed at the time of the study. You asked us to

determine if the 391 aircraft level was excessive. As a result, we

(1) recalculated the Joint Staff’s estimate using the same computerized

model and (2) determined how changes in the flight frequency

assumptions affected the calculation of the aircraft requirements.

Background In May 1995, the Commission on Roles and Missions reviewed DOD’s

post-Cold War direction and the plans to proceed in that direction. Among

other things, its report concluded that there were too many OSA aircraft

and recommended changes to eliminate the excess capacity. In response,

the Deputy Secretary of Defense asked the Chairman of the Joint Chiefs of

Staff to determine wartime requirements and to recommend management

changes to improve efficiency. The Joint Staff subsequently formed an OSA

working group to study the matter.

The group developed an activity-based model to determine OSA

requirements for a conventional war involving two major regional

contingencies. The model, applicable to any theater, was based on

notional requirements of the various commanders in chief for OSA-type

aircraft. The methodology divided each theater or geographic area into a

number of support regions. Within each support region, airfield nodes

(single airfields or a group of neighboring airfields) were identified. OSA

capability was established to connect each airfield node within a support

1

Travel of Government Officials on Government Aircraft (GAO/T-NSIAD-96-85, Dec. 29, 1995).

2

Wartime Requirements for Operational Support Airlift, the Joint Staff (Oct. 1995).

Page 1 GAO/NSIAD-96-157 Operational Support Airlift
B-271915 

region and to connect each support region to every other support region in

the area.

Airfield nodes in each overseas support region were to be connected to all

other nodes within that region by nonstop flights three times a day.

Likewise, each support region in an overseas area was to be connected to

every support region in that area by nonstop flights three times a day.

Because of the ready availability of commercial flights, nodes within the

continental United States were connected an average of 1.5 times a day

and support regions were connected to every other region once a day.

After activity-based requirements were determined, mission-specific

aircraft requirements were identified. Mission-specific requirements

include key commander mobility, required user transportation, remote

link (Caribbean, Iceland, Azores, Africa, South East Asia, etc.)

requirements, surge, and other requirements identified by the commander

in chief. Total aircraft requirements were then determined by applying

service planning factors (10 percent for short-range aircraft and 15 percent

for long-range aircraft) to allow for attrition reserve, maintenance

withholds, and proficiency training. A mission capability rate of 85 percent

for long-range aircraft and 80 percent for short-range aircraft was

validated by the services and built into the Joint Staff’s model.

Results in Brief Our calculation of the activity-based demand differed slightly from the

Joint Staff’s estimate. Using the assumptions set forth in the Joint Staff

study, we found that the Joint Staff estimate was overstated by 

6 aircraft—391 versus our estimate of 385 aircraft.

Subsequent to our initial analysis, we were informed by DOD officials that

they had used a different capability assumption in computing the Pacific

Command’s (PACOM) requirement for long-range aircraft. Instead of using

the assumption that these aircraft can average two round trips per day

between regions, as shown in the Joint Staff study and as reflected in

related briefing charts, their requirement was based on the assumption

that long-range aircraft can average only 1.5 flights per day in PACOM. If we

substitute this assumption in our analysis, we get the same overall aircraft

requirement that was reported in the Joint Staff study. However, our

figures still differ slightly in the appropriate mix of aircraft.

To test how changing the assumption on the number of flights needed

each day between and within overseas regions would affect the Joint

Page 2 GAO/NSIAD-96-157 Operational Support Airlift
B-271915 

Staff’s estimate, we calculated the requirement based on the need for two

rather than three flights a day. Our calculation resulted in a requirement

for 55 fewer aircraft than reported in the Joint Staff’s study. We

recalculated the requirement merely to demonstrate the impact that

changing the assumption would have on aircraft requirements; we are not

questioning the flight frequency requirement established by the

commanders in chief.

Minor Differences

Between Joint Staff

Study and Our

Analysis

Our recalculation of the activity-based demand differed slightly from the

demand determined by the Joint Staff. We determined that five fewer

aircraft would be required. Additionally, our analysis of the service

planning factor yielded a difference of one long-range aircraft. Overall, our

analysis showed a requirement for 6 fewer aircraft than the Joint Staff’s

study, 385 versus 391 aircraft. Table 1 compares the requirement

determination of the Joint Staff with our analysis.

Table 1: Our Recalculation of the Joint

Staff’s Requirement Computation Joint Staff report Our analysis

LongrangeShortrange TotalLongrangeShortrange Total

Mission-specific

requirements 74 50 124 74 50 124

Activity-based 

requirements 62 157 219 59 155 214

Service planning

allowances 21 21 42 20 21 41

Fleet

adjustments 4 2 6 4 2 6

Total aircraft

requirement 161 230 391 157 228 385

Except for two minor differences, our recalculation of the Joint Staff’s

activity-based model matched the Joint Staff’s requirement computation

for each theater. These two differences affect (1) the within-region in the

Northwest continental United States and (2) PACOM’s between-region

requirements. Each involves a mix of long- and short-range aircraft. Table

2 shows the differences.

Page 3 GAO/NSIAD-96-157 Operational Support Airlift
B-271915 

Table 2: Differences in Activity-Based

Requirement Calculation Joint Staff report Our analysis

LongrangeShortrange TotalLongrangeShortrange Total

Northwest 

within-region 5 11 16 4 12 16

PACOM

between-region 19 5 24 17 2 19

Total aircraft

requirement 24 16 40 21 14 35

When we presented our findings to DOD officials, they reviewed the Joint

Staff study for technical accuracy. Their review identified an error in the

Joint Staff study. The study indicated that one of the model’s assumptions

was that long-range aircraft can average two round trips per day between

regions. DOD officials now say that their analysis was based on the

assumption that long-range aircraft in PACOM can average only 1.5 round

trips per day between regions. The lower rate for PACOM is due to the

theater commander’s assessment that two trips per day exceeded

acceptable risk parameters.

Substituting this assumption for the one described in the Joint Staff study,

we recalculated PACOM requirements. We found that the total number of

aircraft needed was 24 as reflected in the Joint Staff study. However, our

analysis did differ slightly on the appropriate mix of aircraft. The Joint

Staff study shows a need for 19 long-range aircraft and 5 short-range

aircraft, whereas our recalculation identified this need as 22 long-range

and 2 short-range aircraft. In other words, changing the assumption

resulted in our analysis agreeing with the 391 requirement established by

the Joint Staff study.

We do want to note that the geographic distances between regions in the

PACOM theater are comparable to those in other overseas areas that use the

standard assumption of two round trips a day. Since we are not aware of

any other factors that would produce significantly different flight

durations in the PACOM theater, we question why the PACOM theater

commander believes the long-range aircraft capability in PACOM is different

than in other overseas theaters.

Sensitivity to Change

in Flight Frequency

The Joint Staff’s activity-based model was based on the commanders in

chief’s assumption that each region in an overseas theater and each node

within a region have to be linked via direct, nonstop flights three times a

Page 4 GAO/NSIAD-96-157 Operational Support Airlift
B-271915 

day. Although we are obliged to accept this assumption, we conducted a

sensitivity analysis using the assumption that two rather than three daily

flights between and within overseas regions would suffice. We found that

the OSA requirement would be reduced by 55 aircraft—33 short-range and

22 long-range aircraft.3

We are not implying that the commanders in chief’s flight frequency

estimate is in any way flawed. Our intent is only to show how a change in

flight frequency could potentially affect the number of OSA aircraft

required to meet wartime requirements.

Agency Comments In commenting on a draft of this report, DOD officials generally concurred

with our report as written. They did, however, reiterate their position

concerning the assumption employed in their calculation of PACOM

requirements for long-range aircraft.

Scope and

Methodology

To validate DOD’s wartime requirement for OSA aircraft, we examined the

following documents from the Joint Staff: a report on wartime

requirements for operational support airlift (Oct. 1995), briefing charts on

the OSA wartime force size methodology, and computer spreadsheets

documenting the OSA study methodology.

Our examination included a review of the above referenced documents

and a recalculation of the Joint Staff’s spreadsheet model and analytical

procedures. We verified the mathematical accuracy of the force-level

estimates in the Joint Staff’s formal report. We fully accepted the Joint

Staff’s judgments about the military scenario and OSA mission

requirements without additional review. We also accepted the report’s

assumptions on mission-specific requirements as well as the operations

and maintenance of OSA aircraft.

We conducted our review from January 1996 to April 1996 in accordance

with generally accepted government auditing standards.

3

We did not recalculate OSA requirements within the continental United States because the ready

availability of commercial flights had already been factored into the Joint Staff model.

Page 5 GAO/NSIAD-96-157 Operational Support Airlift
B-271915 

We are sending copies of this report to the Secretary of Defense. Copies

will be made available to others upon request.

Sincerely yours,

Mark E. Gebicke

Director, Military Operations and 

 Capabilities Issues

(703131) Page 6 GAO/NSIAD-96-157 Operational Support Airlift
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