Expanded flight envelope and more stable software needed as attack role takes on new importance

The newly redesignated Lockheed Martin/Boeing F/A-22 Raptor will be ready for operational testing in the third quarter of next year, according to the US Air Force, following restructuring of the flight- test programme. Operational testing had been planned to begin in April, but aircraft and avionics testing is behind schedule.

Brig Gen Jay Jabour, programme executive officer, fighters and bombers, says there are "several major challenges to conquer" before the F/A-22 can enter initial operational testing. These include "performing the test points to clear enough of the flight envelope". Two aircraft have been "carved out" of the test programme and are being flown more intensively to "clear the part of the envelope that pilots use" before operational testing begins.

Fin buffet fixes have yet to be flight tested, but "we will be done with the issue in a couple of months", said Jabour, speaking at the Air Force Association convention in Washington DC last week. Modified "blow-by" rudder actuators will solve the low-frequency problem, he says. High-frequency vibration will be tackled by altering three ribs at each vertical tail tip from composite to titanium.

The other issue, avionics stability, will be tackled by freezing software development with the next release, Block 3.1.1, and incorporating two minor builds "to ensure it is stable before we move on", says Jabour. This will stretch the schedule, but still support operational testing next year, he says, as Block 3.1.1 has the functionality required for initial operational capability, except Link 16, intraflight datalink and embedded training.

The fighter/attack designation has been adopted "to reflect the aircraft's inherent capabilities", says Jabour. The change results from a "clean sheet" review of the programme ordered earlier this year, and comes as the Department of Defense decides how many the US Air Force will buy. Numbers considered have been as low as 180 and as high as 762, with reports suggesting the USAF wants at least 381F/A-22s compared to the previous plan for 295 F-22s.

The USAF says the F/A-22 will be used for deep strike against mobile targets, such as missile launchers. Armament at service entry in 2005 will include two 450kg (1,000lb) Joint Direct Attack Munitions. An improved radar to be delivered from 2007 will allow new air-to-ground modes to be introduced, and the Small Diameter Bomb will be added once it is developed.


Source: Flight International