FLAP ASYMMETRY, the suspected cause of the 4 August fatal crash, of the Peregrine PJ-2 two-seat jet-powered light aircraft, has occurred twice before on the Bede BD-10, on which the PJ-2 is based. Neither incident resulted in the loss of the aircraft.
Minden, Nevada-based Peregrine Flight International is still investigating the crash, which killed company president Joseph Henderson, but confirms that flap asymmetry is suspected.
Previous company president, Michael Van Wagenen was killed in the crash, on 30 December1994, of the BD-10-based PJ-1, which was caused by structural failure of the tail.
Peregrine acquired the BD-10 design from Bede Aircraft and subsequently withdrew the aircraft from the kitplane market to focus on certification. The PJ-1 essentially, an unmodified BD-10 broke up during a high-speed flight- testing. The causes were structural failure of the vertical tail and flutter of the horizontal tail, says production manager Peter Wilson.
The PJ-2 was modified with redesigned and strengthened vertical and horizontal tails. The aircraft was flown for the first time on 21 June and 33.5h had been accumulated in 26 flights by the time of the accident. Examination of the wreckage revealed that the left flap had been fully extended and the right flap fully retracted at the time of the crash.
The flap mechanism was unmodified from that of the BD-10 and consisted of an electric motor driving two flexible shafts, which powered the left and right flap-actuators.
There was no asymmetry protection. In the previous incidents of flap asymmetry, the aircraft remained controllable. BD-10 designer Jim Bede says, that he now plans to add a tube connecting the left and right flaps, to prevent asymmetry.
Wilson says that privately owned Peregrine has yet to decide whether to proceed with the PJ-2 certification programme. A second aircraft is about two months from completion, he says.
Two BD-10s are being flown, Bede's prototype and a customer's aircraft, and two more are under construction, but no more civil examples of the BD-10 will be produced, Wilson says.
Source: Flight International
