Investigators are advising BAe Jetstream crews to cross-check landing-gear selection on approach, after an Eastern Airways aircraft suffered damage from ground contact when the crew failed to realise the undercarriage had not deployed.
The pilots aborted the attempted landing, at Wick in Scotland on 3 October 2006. Despite damage to its fuselage and propellers, the J32 twin-turboprop (G-BUVC) returned to Aberdeen where it landed without further incident.
Examination of the aircraft by the UK Air Accidents Investigation Branch revealed a cupric oxide build-up in part of the landing-gear selector switch. This deposit, caused by mechanical wear and electrical arcing, insulated the switch contacts, preventing activation of the circuit which lowers the landing-gear.
But the AAIB points out that the three landing-gear indication lights in the instrument panel were not affected, and says: "The crew had not checked the indication prior to landing and were therefore unaware that the landing-gear was retracted."
Other poles on the landing-gear selector switch had functioned properly, stopping terrain-awareness warnings from sounding.
During the initial landing flare on Wick's runway 31 the captain quickly realised the J32 was sinking further that it should, and executed a go-around.
The flight attendant had heard the aircraft contact the runway but did not inform the pilots, who were unaware of any damage. After recycling the undercarriage and verifying that it had deployed, the crew opted to return to Aberdeen.
Eastern Airways has since amended its Jetstream procedures, which had been based on those in the manufacturer's flight manual. Investigators are advising Jetstream operators to adopt a similar change to ensure both pilots cross-check the position of the landing-gear selector switch and the status of the cockpit indicator lights during approach.