What happened
On 13 January 2005, a Piper PA-24-260 Comanche, registration G-BRXW, was returning to Coventry Airport following a flight to Leicester. During the approach, the pilot attempted to extend the landing gear, but the mechanism stopped while only partially deployed. The pilot observed that the landing gear motor circuit breaker had tripped and would not reset. After being notified by the control tower that the nose gear appeared unlocked, the pilot proceeded to a nearby visual reference point at Drayton Water to attempt the manual free-fall mechanism. This attempt was unsuccessful.
After orbiting the area for approximately 50 minutes to reduce fuel weight and wait for the sun glare to subside, the pilot followed air traffic control advice to land on the grass section of the northern taxiway. Upon touchdown, all three landing gear units collapsed, causing the aircraft to slide to a stop. The pilot and one passenger evacuated the aircraft without any injuries.
The investigation
The investigation focused on the electrical and mechanical operation of the landing gear system. The Piper PA-24-260 Comanche utilizes a single electric motor to actuate all three gears via a transmission and a system of cables and rods. Investigators determined that the landing gear motor relay had suffered an internal short-circuit, which caused the circuit breaker to trip and halted the motor's operation.
While the aircraft is equipped with a manual release lever to allow the gear to drop via gravity, this mechanism failed to function. The investigation noted that the landing loads during the collapse caused significant damage to the actuation system. It was suggested that the unusual position of the semi-extended gear may have created mechanical forces that prevented the successful use of the manual release.
Findings
- The primary cause of the electrical failure was an internal short-circuit within the landing gear motor relay.
- The landing gear remained partially extended because the motor could not operate due to the tripped circuit breaker.
- The manual free-fall mechanism was rendered ineffective, potentially due to the specific semi-extended state of the gear at the time of the attempt.