Pratt & Whitney is inspecting an F135 test engine after it shut down automatically following a stall indication during hover mode testing of the propulsion system for the short take-off and landing Lockheed Martin F-35B Joint Strike Fighter.
The anomaly occurred on 30 August on a test stand at P&W's West Palm Beach, Florida facility, during control model verification testing with the engine in powered lift mode - the shaft-driven lift fan, rolls posts and three-bearing swivel nozzle operating.
P&W says it does not know what caused the anomaly, which had not occurred before on this or other F135 test engines, and has stopped all testing until the cause is know. But it is not expected to delay first flight of the STOVL F-35B in May next year.
Meanwhile, the fourth and final US Congressional subcommitte has voted to restore funding for the General Electric/Rolls-Royce F136 alternative engine for the JSF. The US Department of Defense had tried to cancel the programme to save money.