The accident was notified to the Air Accidents Investigation Branch (AAIB) by Wick Air Traffic Control at 1800 hrs on 3 October 2006. The AAIB investigation team consisted of:
Mr A Simmons Investigator-in-Charge
Mr M Ford Flight Recorders
Mr P Hannant Operations
Mr B McDermid Engineering
The aircraft was on a scheduled flight from Aberdeen to Wick. It was the fourth sector of a six-sector day for the crew, during which there had been no significant delays. The crew flew the VOR/DME procedure for Runway 31, and became visual with the runway during the latter stages of the arc portion of the procedure. They configured the aircraft with the landing gear selected ‘DOWN’ and flaps set as required for the approach and landing. The commander, who was the Pilot Flying, flared the aircraft for touchdown at the normal height but as the aircraft continued to sink, he realised that the landing gear was not down. He carried out a go-around and, following a recycling of the landing gear, flew past the control tower. The controller confirmed that the landing gear was down and the aircraft diverted back to Aberdeen Airport where a safe landing was made. It was subsequently found that, during the go-around, the underside of the fuselage and the tips of the right propeller had contacted the runway surface.
The investigation found that contamination of the landing gear selector switch points had acted as an electrical insulator preventing current flow to the landing gear lowering system and audible warning systems. The three green landing gear indicator lights, which are independent of this circuit, had functioned correctly. The crew had not checked the indication prior to landing and were therefore unaware that the landing gear was retracted.
The investigation identified the following causal factors:
Mechanical wear and arcing across one of the poles in the gear selection switch resulted in a piece of cupric oxide acting as an insulator across the pole which should have energised the gear extension circuit.
The flight crew did not identify that the landing gear was not down and locked by visually checking the landing gear green indicator lights.
Due to the failures associated with the gear selection switch, the flight crew received no audible warnings of the landing gear not being in the ‘DOWN’ position.
As a result of the investigation, four Safety Recommendations have been made. Two of these were made at an early stage of the investigation to the US Federal Aviation Administration.
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3-2008 G-BUVC.pdf (3,066.56 kb)