What happened
On 17 September 2011, a Beech 76 Duchess, registration G-OADY, was conducting a training flight at Leeds Bradford Airport. The flight was being operated by a pilot undergoing instruction for a Commercial Pilot’s Licence, accompanied by an instructor. During the flight, the crew performed stall recovery exercises in a landing configuration.
As the aircraft approached the circuit, the pilot-under-instruction noticed the airspeed was lower than expected. During the landing roll, approximately 100 to 150 metres into the run, the nose landing gear collapsed, causing the aircraft to come to an abrupt halt. The incident resulted in no injuries to the two crew members, though the aircraft sustained damage to the engines, propellers, nose cone, and nosewheel bay doors.
The investigation
The investigation focused on why the nose gear failed to remain extended. The crew initially believed the landing gear lever might have been accidentally moved to the UP position by the student pilot's knee. However, testing revealed that the gear selector requires being pulled out before it can be moved to the UP position, making an accidental knock from the locked-down position impossible.
Investigators established that while the three green lights remained illuminated, the gear was not actually locked down. It was determined that the selector lever had been moved several times during the training exercises and may have been left in a position where the gear was down but not mechanically locked. The investigation found that if the selector is pulled out and the gear is not fully locked, the lights can remain green even though the gear is unsafe.
Findings
- The nose landing gear collapsed because the gear was not mechanically locked in the down position.
- The landing gear selector lever had been manipulated during training exercises and was likely left in a partially unlocked state.
- The landing gear was not properly locked down despite the green lights being illuminated.
- The aircraft's hydraulic interlock system allowed the green lights to remain active even when the gear was not securely locked.