PAUL LEWIS / LANGLEY AFB
The US Air Force remains optimistic that the Lockheed Martin/Boeing F-22 Raptor will enter frontline service by late 2005, despite recent developmental problems and setbacks that will probably delay the start of dedicated initial operational test and evaluation (IOT&E) by up to six months.
"The decision to begin [IOT&E] is event driven and that means we'll make a decision when we're confident the aircraft will enter and pass. The current schedule has that starting in April 2003É.We have some funding reserves so that if we slip that date we can afford to do that. It appears that slip may be three or six months," says Brig Gen William Jabour, USAF F-22 programme director.
One issue is the recent discovery of vortex buffeting of the fins. A number of solutions have been considered including installing fences on the engine inlet, but the USAF's preferred solution is to strengthen the tail tip and modify the rudder actuator. Evaluating the fix will add another month to flight testing.
Another area of concern is mission system software, which periodically needs rebooting. "We have made significant progress over the five or six months, but stability is not where we want it and we need to make some improvements before IOT&E," say Jabour. More time is needed to clear the flight envelope, test avionics functionality and verify maintenance technical orders.
IOT&E will involve the last three of the nine F-22 development fighters - the last of which was delivered to Edwards AFB, California, on 31 May - and the first two of eight production representative test vehicles. "If we can begin IOT&E by the middle of next year, we can still hold to the IOC [initial operational capability] date," says Jabour.
IOC requires the first squadron to have enough trained pilots and a full complement of 24 Raptors by December 2005.
Source: Flight International
