Fuel Pump Software, Inlet Door Hinges Questioned. Flights Resume Tuesday

The Pentagon late last week suspended flight testing of all variants of the F-35 Lightning II Joint Strike Fighter after problems were discovered with software that controls the airplane's three fuel boost pumps. An additional issue was discovered with the auxiliary inlet door hinge during a post-flight inspection of the BF-1 STOVL aircraft, and short takeoff/vertical landing mode testing has also been prohibited while that problem is addressed.

File Photo

The aux inlet doors are just aft of the lift fan and open to allow additional air to enter the engine during STOVL operations such as hover and slow flight.

The Air Force Times reports that the software problem affects the fuel pumps in all three models of the JSF was discovered during lab testing. Pentagon spokesperson Cheryl Irwin said that the problem "could have possibly triggered a shutdown on the three boost pumps, which could potentially cause an engine stall.” While she said a simultaneous shutdown of all three pumps would be very unlikely, “prudence dictated a suspension of operations, temporarily, until the fuel boost pump signal timing was corrected.”

STOVL F-35

Lockheed Martin spokesperson John Kent said that flight testing was set to resume Tuesday after updated software was delivered and installed over the weekend, but that STOVL testing would not resume until the root cause of the hinge issue has been identified.

FMI: www.lockheedmaritn.com, www.defense.gov