History of the flight
The aircraft, a TBM 700C1 (N700GY), departed Biggin Hill for Alderney with one pilot on board. When the pilot selected the landing gear up, the green nose gear light did not extinguish and the red landing gear warning light remained on. The pilot made several unsuccessful attempts to retract the gear before consulting the Pilot's Operating Handbook (POH) and decided to continue with the gear down. The aircraft landed at Alderney with three green lights and a continuous red light showing. During the rollout at approximately 40 kt, the nose gear leg collapsed, causing the propeller and nose to strike the paved runway. The aircraft departed the runway and came to a stop on a taxiway. The pilot shut down the engine and evacuated via the main door. No injuries were sustained.
Post-accident examination
The nose gear actuator was removed and examined at the manufacturer's facility. Functional testing revealed an anomaly: the actuator successfully retracted and gave correct up-lock indications, but almost simultaneously provided down-lock indications, meaning the actuator had indicated both locked up and down. This anomaly could have produced the continuous red light. Internal examination showed faint witness marks, possibly from small fragments that could have caused a malfunction, but no contamination was found. After reassembly, the actuator operated normally.
Other similar incidents
The aircraft had experienced two similar events in the four months preceding the accident, both occurring during gear retraction. All post-incident maintenance tests found no fault. Another TBM 700 suffered a nose gear collapse at Paris Le Bourget in September 2007 after a similar indication sequence; the pilot did not follow the hand pump procedure.
Analysis and Safety Recommendation
The POH states that a continuous red warning light indicates a landing gear locking problem, irrespective of the condition of the green lights. However, the pilot interpreted the three green lights as confirmation that the gear was locked down. The lack of clarity in the POH regarding the significance of the red light was considered a causal factor. The AAIB issued Safety Recommendation 2009-002, recommending that EADS Socata amend the POH to clarify the need for manual extension of the landing gear if a continuous red light is showing, even if the green lights are lit.