GE-RR Halt F136 Tests for Debris Check
Guy Norris/Dayton, Ohio guy_norris@aviationweek.com 
The GE Rolls-Royce F136 Fighter Engine Team is investigating the source of debris in the oil system that has forced tests of the F-35 Joint Strike Fighter alternative engine to be halted.
The first production-configuration F136 has been running since Jan 30, and was nearing the end of its initial test runs when engineers noted a drop off in test data, even though the engine continued to operate smoothly. A GE R-R spokesman says tests were halted as a precaution when monitors detected debris in the oil system.
The joint venture says "critical instrumentation sensors were lost," and that as a result the engine is being disassembled to investigate the issues, "as well as to evaluate test results and findings from the break-in run. An estimate for returning to test is pending the investigation findings."
Engineers are working three shifts a day to address the issue, says GE R-R, which currently has only this single test asset available to the program. Not only is it keen to resume tests of the initial engine, 625-004, but GE R-R is also eager to discover any issues that may need to be corrected before subsequent engines are completed. These include upcoming conventional-flight test engines 005 and 006. Engine 006 will be used for initial flight readiness qualification for the first F136-powered F-35 flight in 2010.
The first F136 for flight tests is scheduled to be delivered to JSF prime Lockheed Martin in March 2010. Engines 007 and 008 are aimed at short-takeoff-and-landing (STOVL) tests, with 008 undertaking the flight qualification work. First flight of the F136-powered F-35B STOVL variant is set for 2011.
Although nothing is said officially, program sources indicate the engine could be ready to resume tests in three to four weeks time.
With critical questions looming over the upcoming budget and expectations of yet another battle for funding, the GE R-R team is playing down the incident. "As testing on the F136 began a month ahead of contract date, that will diminish any impact to the test schedule," it says. It also adds that in tests so-far, engine light-off, acceleration and vibration characteristics have "met or exceeded pre-test predictions."
The F136 is being developed under a system-development-and-demonstration contract with the F-35 Joint Program Office as the alternate engine to Pratt & Whitney's F135. The Defense Department and the Air Force have officially declined to support the alternative program for years, saying precious funding could be better used elsewhere. However, USAF officials have privately said an alternative power plant is not necessarily a bad idea as long it does not detract from other JSF funding. Congress has repeatedly earmarked for the alternative engine despite White House objections under the last Bush administration.
Photo credit: Lockheed Martin
