RM&A Evaluation Was Less Demanding Than Originally Planned

The C-17 met or exceeded 10 of the 11 RM&A evaluation contract specification requirements. The decrease weakened the link between the evaluation as executed and the RM&A measurement criteria. In addition, the evaluation was less demanding because the number of airdrops and landings on small austere airfields was decreased and lighter average cargo loads than called for in the contract specifications were carried. Command officials were also concerned that the 1992 draft plan would not demonstrate the aircraft’s wartime surge utilization rates included in the C-17 Operational Requirements Document. In July 1994, the Air Force issued the revised RM&A evaluation plan. The impact of these changes was longer duration wartime sorties and a reduced ratio of sorties to flying hours, resulting in less stress on the RM&A aircraft than originally planned. However, the evaluation was not intended to provide a statistically valid basis for predicting the C-17’s ability to meet its wartime surge rate. Aircraft Could Not Perform Formation Personnel Airdrop or Aeromedical Evacuation Missions

According to the C-17 development contract, the RM&A incentive fee was to be based on the degree that the contractor met each of 11 individual RM&A parameter goals. In our opinion, none of the aircraft should have been considered full mission capable during the evaluation. First, the Air Force, based on the results of developmental testing, had restricted the aircraft from executing the formation personnel airdrop mission under operational conditions for safety reasons. Comparison of C-17 30-Day RM&A Evaluation With Results of Operational Test and Evaluation

RM&A evaluation July 7 to August 5, 1995 MTBM(i)
MTBM(c)
Mission capable (capable to perform at least one mission) Full mission capable (capable to perform all missions) Mission completion success probability (complete mission objectives without experiencing failure or performance degradation due to equipment problems) Mean time between maintenance-inherent (mean flight hours between unscheduled, on-equipment, inherent maintenance actions) Mean time between maintenance-corrective (mean flight hours between unscheduled corrective actions) Mean time between removal (mean flying hours between removal of any repairable equipment) Maintenance man hours per flying hour (total maintenance hours expended for each flight hour) Mean man hours to repair (the mean maintenance man hours required to complete a corrective maintenance action) Built-in-test fault detection (percentage of occurrences in which BIT correctly detects a malfunction) Built-in-test fault isolation (percentage of occurrences in which BIT correctly isolates a detected malfunction to the failed equipment item) Built-in-test false fault indication (percentage of occurrences in which BIT indicated a malfunction when none existed)

Comparision of Flight Hours, Sorties, and Average Sortie Time Between Original RM&A Plan, Revised Plan, and Actual

Revised plan (July 1994)
Original plan (October 1992)
Difference between revised and original (36) (17) (32) (15) (0.16) (05)

Comparison of Actual RM&A C-17 Aircraft Cycles/Sorties With Estimated Cycles/Sorties Using Average Sortie Times Contained in Original Plan

RM&A Evaluation Incentive Award Fee Calculation

MTBM (I)
MTBM (C)

Comments From the Department of Defense

Major Contributors to This Report

	National Security and International Affairs Division, Washington, D.C.

	Los Angeles Field Office

Noel J. Lance Dorian R. Dunbar Larry J. Bridges The first copy of each GAO report and testimony is free.
Why GAO Did This Study

Pursuant to a congressional request, GAO reviewed the Air Force's reliability, maintainability, and availability (RM&A) evaluation of the C-17 aircraft, focusing on: (1) RM&A planning, preparation, execution, and results; and (2) whether the evaluation demonstrated the aircraft's wartime surge rate.

What GAO Found

GAO found that: (1) the Air Force reported that the C-17 aircraft met or exceeded 10 of the 11 contract requirements during its RM&A evaluation, but the evaluation was less demanding than originally planned; (2) although the revised RM&A evaluation plan increased total flying hours, the number of sorties, and average wartime sortie duration, it decreased the ratio of sorties to flying hours, which weakened the application of RM&A measurement criteria and lessened the stress on the aircraft; (3) the RM&A evaluation also had fewer airdrops and austere airfield landings than originally planned, and the aircraft flew cargo loads that averaged less than one-half the weight projected in contract specifications; (4) three years of operational testing show that the aircraft generally met RM&A requirements with the exception of those related to built-in-test parameters; (5) the RM&A evaluation was not a statistically valid test for determining C-17 fleet wartime utilization rates because the test's duration was too short; and (6) the incentive fee should have been reduced, since the aircraft could not perform the formation personnel airdrop mission under operational conditions, or the aeromedical evacuation mission.