AAIB investigation to Piper PA-24-250 Comanche, G-BYTI
Landing gear collapsed after landing, Retford Gamston Airfield, Nottinghamshire, 21 May 2017.
Summary:
This was the first flight after the main landing gear had been refitted following repairs. A new squat (safety) switch was installed prior to the flight and landing gear functional tests were completed in accordance with the published procedures.
The pilot’s intention was to fly one circuit with the landing gear down, before landing and coming to a full stop. He reported that everything was normal with the landing gear indicating down and locked until he applied the brakes after touchdown, at which point the undercarriage collapsed.
The maintenance agency reported that the landing gear retraction mechanism was undamaged and the configuration of the ball screw and transmission indicated that the landing gear had been retracted by the electric motor. The circuit breaker for the electric motor was found to have tripped.
The safety switch prevents the landing gear from retracting if the left main landing gear leg is compressed and multiple failures are required for the landing gear to retract without selection. The pilot reported that he had not operated the landing gear selector lever at any stage of the flight.
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