The Boeing Lockheed Martin F-22 programme faces a four month delay in the start of the critical initial operational test and evaluation (IOTE), because of a shortfall in development flight testing.

"We might be 100h short as we lay out the plan to transition to IOTE," says Lawrence Delaney, air force assistant secretary for acquisition "We're looking at the number of flight months and looking at the flight test matrix and there is no doubt it is tight."

Three pre-production F-22s amassed nearly 635 hours by mid-June. This was after an almost four-week grounding after the discovery of "hairline surface cracks" between 6mm and 13mm (0.25 and 0.50in) long in the canopy transparency and frame attachment area. An earlier problem with the delamination of a composite flaperon rib is also cited as a cause for the shortfall in flying time.

Flight tests were due to be finished by late 2002, with 25% of flying due to have been completed this year. This comes at a critical time for the F-22 programme, which is under pressure on two fronts to met a Congressionally mandated end of year development criteria and cost cutting plan.


The fourth pre-production F-22, equipped with full sensor fused Block 3.0 software, is due to fly on 4 December. The release of funds for the first 10 low rate initial production aircraft depends on the success of test flying this aircraft. Raptor 04 is undergoing engine test runs and will make its first flight in mid-August equipped with Block 1.2 software.

Boeing F-22 avionics director Michael Harris says the initial Block 3S software, of which only 30% is fused, has logged 45h on the Boeing 757 flying test bed (FTB). Block 3.0 is to be released on 6 October and the aircraft will undergo "five weeks of pretty intensive FTB testing before being delivered to Lockheed Martin," says Harris.

Additional end of year criteria call for first flight of the sixth pre-production F-22, now set for 20 December, 100h of load testing and completion of 40% of initial life fatigue testing, to start in October. "We are meeting all our objectives," says Delaney.

Source: Flight International