The AAIB released their final investigation reporting regarding the accident involving a Jetstream 31 in October 2006.
The aircraft was on a scheduled flight from Aberdeen to Wick. 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 The crew had not checked the indication prior to landing and were therefore unaware that the landing gear was retracted. (AAIB)