Lockheed Martin's long-delayed F-35 flight-test programme faces a new level of pressure to perform this year, but so far the company is keeping on track.
First flight of an F-35C test aircraft, featuring a 22% longer wing to land on aircraft carriers, ended successfully in Fort Worth, Texas on 6 June. With its 13.1m (42.9ft) wingspan, the carrier variant landed at 135kt (250km/h), compared with 150kt for the F-35's other two versions.
The milestone event came much later than originally planned. The aircraft - named CF-1 - ceremoniously "rolled out" nearly 11 months ago. But the US government approved a new schedule earlier this year, and CF-1's airborne debut is another sign that the flight-test programme is roughly adhering to a reduced series of goals.
Tom Burbage, Lockheed's executive vice-president and general manager of the F-35, admits shortfalls remain.
Lockheed is scheduled to complete 394 flight-test sorties this year, averaging 10 test points per flight. So far, it is tracking slightly above the required number of flight tests but slightly below the goal for test points, Burbage says.
Keeping on schedule has assumed a new importance this year. A frustrated House of Representatives has proposed slapping conditions on F-35 funding next year.
If the House's version of the fiscal year 2011 defence authorisation bill clears the Senate, the Department of Defense could withhold funds for 12 of 42 F-35s. To release the funding, Lockheed must complete all scheduled flight tests, test points and, not least, first flight of CF-1.
Meanwhile, the flight-test fleet continues to grow. CF-1 is the eighth aircraft built under the system development and demonstration phase to enter flight-testing. The ninth flying aircraft - also the third conventional take-off and landing (CTOL) variant named AF-3 - was also poised to achieve its first flight in early June.
As the focus of flight-testing shifts from basic flight sciences to mission systems, Lockheed is entering a more challenging phase. Both AF-3 and the fourth short take-off and vertical landing (STOVL) aircraft, BF-4, which started flying two months ago, are dedicated to checking out the aircraft's advanced sensors and avionics.
Lockheed still remains cautiously optimistic. Static tests are now completed on the CTOL and STOVL versions, Burbage says. The carrier variant's static testing is 80% complete, and, he adds, has gone so well that programme officials may reduce the number of test points for the flight test aircraft to complete.