Fanal Report: Lift dump problems plague Premier 1
Raytheon 390 Premier I, Blackbushe Airport, Hampshire, UK, April 7, 2004– According to the UK Air Accidents Investigation Branch report, the instrument-rated pilot of Premier N200PR was unable to raise the landing gear after takeoff from Humberside Airport. He tried unsuccessfully to recycle the gear and noticed lift dump and antiskid systems failure indications. He landed at Farnborough to discuss the problem with an engineer from the aircraft’s maintenance organization. There were no obvious problems, but the engineer, aware of a history of lift-dump system problems with the aircraft type, suggested that the aircraft be ferried to Blackbushe, the maintenance base, for further investigation. The pilot did not attempt to raise the gear again. On landing at Blackbushe, the aircraft left the runway, stuck a series of obstructions and was destroyed. The sole-occupant pilot was not injured.
The support bracket for the right main landing gear weight-on-wheels (WOW) switch was found to have failed before the crash, causing the failure indications the pilot reported.
After the owner bought a Premier, the pilot experienced “a number of teething problems,” many involving the lift-dump system. In November 2003, the manufacturer replaced the Premier with a new aircraft. The pilot said that although reliability improved somewhat, some problems remained. The continuing difficulties with the aircraft’s reliability had affected the pilot’s confidence in the machine and, in particular, he lacked confidence in the authenticity of the aircraft’s warning systems.
The Premier’s lift-dump system had six spoiler panels, three on each wing. The two outboard spoiler panels on each wing provided speedbrake function and roll augmentation. The inner spoiler panel along with the two outer spoiler panels accomplished lift dump. If a discrepancy between the left and right WOW switches persists for more than six seconds, the spoiler-control unit will fail the lift-dump system.
Because of a number of previous landing accidents implicating the lift-dump system, the FAA had issued two ADs that imposed restrictions on the aircraft landing performance, and Raytheon issued a Service Bulletin to modify the system. N200PR had been modified.
Another problem the AAIB noted was that the aircraft rolled onto its left side, possibly making it difficult to open the main access door. The emergency exit door on the right side had fallen into the aircraft and the pilot was able to escape. Since the door had fallen inward, due to distortion of the composite airframe during the accident, said the AAIB, if passengers had been seated in the rows adjacent to the door, they might have been injured.
The AAIB issued several recommendations, including that the manufacturer review the weight-on-wheels switches and the logic of inhibiting the system due to a WOW disagree and of displaying an “anti-skid-fail” warning for a WOW disagree, when the system is otherwise operational. The agency also recommended adjustments to the flight manual checklist to make them less susceptible to errors of interpretation.