What happened
On 4 May 2019, at approximately 21:59 UTC, a Learjet 45, registration C-GMCP, was undergoing pushback from its gate at Edinburgh Airport. The aircraft, operating as non-revenue commercial air transport, was being moved by a TLD 150 Max tug. During the maneuver, as the tug was turning the aircraft to align with the taxiway, the nose landing gear suddenly collapsed toward the rear. There were no injuries to the two crew members or the two passengers on board, though the aircraft sustained damage to the nose landing gear leg, its support, and the actuation mechanism.
The investigation
The AAIB examined the aircraft's nose landing gear assembly, noting that on this specific model, the gear is designed to retract in a forward direction. Investigators identified that a bracket to which the nose landing gear actuator is attached had failed. A metallurgical analysis of this bracket determined that the failure was the result of an overload, with no evidence of fatigue or pre-existing material defects being present.
During the investigation, the co-pilot noted that he had been performing cockpit checks and adjusting the position of the rudder pedals. He indicated that he might have unintentionally applied the brakes during the process, though he was not certain.
Findings
- The failure of the bracket was caused by an overload.
- The aircraft manufacturer noted that the damage pattern observed was consistent with previous incidents involving the Learjet 45, including an event at their own production facility and two other in-service occurrences where brake application during pushback led to a rearward gear collapse.
- The collapse of the nose landing gear on C-GMCP was most likely caused by the inadvertent application of the brakes during the pushback operation.