has passed its 2011 flight-test targets for the Joint Strike Fighter, with aircraft now flying at a pace that, if maintained, will allow the company to exceed its target for a significantly higher number of flights in 2012.
The test program completed its 875th flight for the year on Nov. 17, passing the full-year target of 872. A total of 6,809 test points were accumulated on those flights, exceeding the year-end target of 6,622, says J.D. McFarlan, Lockheed vice president for F-35 test and verification.
The 2011 target was passed early despite testing being halted twice: once briefly in March after an inflight dual generator failure, and for two weeks in August after a failure of the aircraft’s integrated power package during ground runs.
Flying of some F-35B short-takeoff-and-landing test aircraft has again been halted, this time to replace structural beams in the lift-fan bay that have developed small cracks. The beams support actuators for the upper and lower lift-fan doors.
McFarlan says the actuator supports were identified as “hot spots” during structural testing, and Stovl (short takeofff and vertical landing) aircraft from test jet BF-5 onward have redesigned beams and are not affected.
Aircraft BF-1 has been fitted with the redesigned support beams and is planned to return to flight at NAS Patuxent River, Md., in December. BF-2 will be modified during scheduled down time, he says.
BF-3 has done less Stovl testing and has not yet developed cracks. It will be modified, as will BF-4, which for now is being used for up-and-away flight testing. “BF-3 and -5 are available to do Stovl work, so this is not holding us up,” McFarlan says.
In January, the F-35 test program was replanned and extended by two years to provide additional margin for discoveries and to refly test points. “Flying rates in the new plan were supposed to accommodate such findings, and we are happy with its ability to do so,” he says.
Since flying resumed in mid-August, the F-35 test fleet has been averaging 100 flights a month. “That is slightly higher than the pace we need in 2012,” McFarlan says. Around 1,100 test flights are planned for next year.
Although Lockheed has exceeded its full-year target for test points, they are not quite in the order planned. “We have about 500 more in the CV [F-35C carrier variant] bucket than the plan and about 100 more of CTOL [conventional-takeoff-and-landing F-35A] and Stovl to accomplish.”
A major objective of flight testing in 2011 was to deliver data to clear the initial envelope for flight training. “We have done that, and delivered several updates to that envelope,” McFarlan says. Training on the F-35A at Eglin AFB, Fla., has yet to begin.