Graham Warwick/FARNBOROUGH
Flight testing of the Lockheed Martin/Boeing F-22 is "on track" to meet a deadline set by the US Congress, which wants to be convinced that the fighter is meeting its performance goals before releasing funds for the first production-standard aircraft.
Congress has demanded that 183h of flight testing be completed before funding for two "production representative test vehicles" can be released. The US Department of Defense (DoD), meanwhile, has established some key test points, or "exit criteria", which must be accomplished before a 31 December deadline also tied to release of the funds.
F-22 chief test pilot Paul Metz says the US Air Force has tasked the test team at Edwards AFB, California, with achieving the Congressional and DoD targets by late November, to ensure that conditions are met for release of production funding at the beginning of next year. USAF F-22 test pilot Col Steve Raimey says the team should have "no problem" meeting the deadline.
The two F-22s now flying had accumulated a total of 60h by the beginning of September. Several of the DoD exit criteria have already been achieved, says Metz, including: clearance of the so-called E-0 and E-1 flight envelope zones; flights in the E-2 and -2A zones; aerial refuelling; and flight above 30,000ft (9,000m).
The second flight-test F-22, aircraft 4002, was scheduled to begin high angle-of-attack testing in the first week of September, with the aim of meeting the requirement of flying above 18í. Metz says the aim is to reach 26í by October. The first F-22, aircraft 4001, has to complete a full ground vibration test now under way and is then expected to make the fighter's first supersonic flight, also in October. Opening and closing the weapons bay doors, another of the DoD's exit criteria, is expected to be accomplished "in the next couple of months", says Metz.
The test team praises the handling qualities of the F-22, saying there have been few problems. A "roll jerk" phenomenon has been traced to the rudders being more effective than required. "The rudders are exactly as effective as the windtunnel said they would be, but that was not the case with the prototype," says Metz, who says that the problem will be cured by modifying the flight control software.
Source: Flight International
