Military Aircraft:

C-17 Wing Flap Requires Additional Testing

NSIAD-92-160: Published: Jul 8, 1992. Publicly Released: Jul 8, 1992.

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GAO reviewed results of temperature and acoustic testing on the C-17 aircraft's flap to determine whether the contractor had demonstrated that the flap would achieve the required 30,000-hour life expectancy.

GAO found that: (1) the Air Force's review of the contractor's test results raised serious concerns about whether the current flap design could meet the contract performance requirement of 30,000 flight hours; (2) the Air Force and the contractor have begun to acquire flight test data from the developmental aircraft, which will result in assessments of aircraft performance, but will not yield flap life-expectancy estimates; (3) to obtain life-expectancy estimates, the acquired data would have to be used in an environment test that would account for the effects of sound and heat on the flap; and (4) the contractor believes that additional testing is unnecessary and plans to rely on analysis and extrapolation from the actual data.

Recommendation for Executive Action

  1. Status: Closed - Implemented

    Comments: The Air Force has determined that both the flaps and slats need to be redesigned to ensure that they meet a 30,000 hour life expectancy. The redesign is complete and the aircraft are in the process of being retrofitted.

    Recommendation: The Secretary of the Air Force should direct the Program Executive Officer to establish test plans to determine whether the C-17 flap meets the required 30,000-hour life expectancy before the C-17 goes into full-rate production.

    Agency Affected: Department of Defense: Department of the Air Force


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