AEDC testing benefits future of F-35 fleet

Published Nov. 4, 2015
By Deidre Ortiz
AEDC/PA

ARNOLD AIR FORCE BASE, TENN. -- The full hot-life capability of Pratt & Whitney's F135 engine, which is used in the F-35 Lightning II, was successfully demonstrated during Accelerated Mission Testing in test cell Sea Level 2 at the Arnold Engineering Development Complex.

Sponsored by the U.S. Air Force Engine Component Improvement Program Office, the test focused mainly on the Conventional Takeoff and Landing engine variant that powers the F-35A model for the service. CTOL development represents a key milestone of the F135 program.

According to Michael Astahoff, chief of the CIP Branch for the Air Force, "Due to the component commonality across all three F-35 variant engines, the lessons learned will save costs for the entire fleet, including the [other] services and the non-U.S. participating countries."

The engine achieved 5,210 total accumulated cycles, or more than seven years of operation, in 235 days of testing. This is equivalent to approximately 1,200 F-35 missions.

AMT is performed to evaluate reliability and maintainability performance of the engine over its life span. The testing is also used to identify potential issues before they are encountered by the operational fleet. During AMT, engines accumulate hours under monitored conditions and accrue hours at a faster rate than when operating in the aircraft.

John Kelly, deputy for operations of the Aeropropulsion Combined Test Force at AEDC, stated that, on average, 55 total accumulated cycles were achieved in a single day of testing, with the maximum number of 101 TACs in a day. That amounts to about 30 sorties in the field.

Kelly added this was the first time that SL-2 has been used for an F135 Test.

"The CIP Office helped fund the SL-2 upgrade to F135 capability because they see the value in AEDC testing," he said.

Mike Dent, deputy director of the Aeropropulsion Combined Test Force, also commends Kelly for diligently advocating to CIP for the upgrade as a high pay-off, risk reduction strategy.

"[Kelly] foresaw increased workload where there may be a need for capability to test more than one F135 at once," Dent said. "He was proven correct. During planning for the upgrade, it was determined that we would have F135s in the SL-3 and SL-2 facilities at the same time. The upgrade was completed just five weeks prior to commencement of the F135 CTOL engine AMT."

Mark Buongiorno, vice president of the F135 Propulsion System for Pratt & Whitney, commented in a press release that the test results are beneficial to the future maintenance of the F-35 fleet.

"We are delighted with the exceptional performance of the F135, and are proud to partner with our U.S. Air Force customer on this important program testing," he said. "Being able to conduct a full-life overhaul, years ahead of the remainder of the operational fleet, provides valuable insight and confidence in the robustness of this engine's design."

Advanced data from the test program has led to improvement opportunities aimed at determining the life cycle cost expectations for the entire F135 CTOL powered F-35 fleet.

In all, the F135 program has tested over 5,510 hours in five different test cells at AEDC.