Faulty Parts Delay F-35B STOVL Flight Tests

Failed components and delayed follow-on maintenance are to blame for F-35B STOVL flight tests falling behind schedule.

On Lockheed Martin’s 2nd quarter conference call yesterday, CEO Bob Stevens told Wall Street analysts (transcript here) the F-35 Joint Strike Fighter program was at a “critical juncture” as it transitions from development into production.

The systems development and demonstration phase is about 80 percent complete, he said. Of the 19 planned test aircraft, 15 have been delivered; only 13 will actually fly, the others are for structural tests. Nine of the “flyers” have so far completed a total of 136 test flights: the F-35A has flown 56 times; the F-35B short-takeoff and landing version has flown 74 times: and the carrier variant F-35C has flown six times.

"While the 74 test flights of the F-35B might look impressive, its actually behind schedule; it was supposed to have flown 95 times by now", Stevens said. “Higher than predicted” failure rates of component parts have grounded some F-35B test aircraft. Stevens described the failing parts as sub-components, not major parts such as the engine, which has been performing well.

“The components that are failing are more of the things that would appear either smaller or more ordinary like thermal cooling fans, door actuators, selected valves or switches or components of the power system.”

Yet, testers have had to pull the engines out to access those failed components and the follow-on maintenance has taken far longer than expected, Stevens said. Lockheed and its suppliers are trying to figure out whether the problems lie in botched manufacturing (Friday jobs), whether the design of the parts must be changed or whether the program needs to buy more spares. Stevens said the problem is fixable.

By: Shelldrake