Inadvertent crew braking during taxi pushback likely led to the nose landing gear (NLG) collapsing on a 2000 Bombardier Learjet 45 (registration C-GMCP) on May 4, 2019, at Scotland's Edinburgh Airport, according to a UK AAIB final report released today. There were no reported injuries to the two passengers or two crewmembers.

At the time of the mishap, the captain had 2,669 hours in type and 12,920 hours total time. The aircraft appears to have been operated by Skyservice Business Aviation.

The pilots started both engines at the gate before the aircraft was pushed back using a TLD 150 Max tug. As the aircraft was being turned to line up on the taxiway, the NLG suddenly collapsed aft and the aircraft came to rest.

During pushback, the copilot had been carrying out checks and had started adjusting the position of his rudder pedals. He was bringing the pedals aft and he said there was a possibility he might have tapped the brakes, but was not aware of having done so.

Examination of the aircraft showed that the nose leg bracket connected to the gear actuator had failed, allowing the NLG to collapse aft. (The Learjet 45's nose gear retracts in the forward direction.)

The bracket was examined at a metallurgical lab, revealing that it had failed due to overload. There was no evidence of material defects or fatigue, the AAIB said. It added that the aircraft manufacturer had examined photographs of the structural damage to the NLG bay and stated that this damage and the damage to the bracket was similar to the damage that occurred to a Learjet 45 at its production facility, which occurred during pushback with brake application. The company said it was also aware of two other in-service events in which brake application during pushback resulted in the same rearward NLG collapse.