What happened
On 13 February 2009, an Avro 146-RJ100, registration G-BXAR, was performing a scheduled passenger flight from Amsterdam to London City Airport. The approach and touchdown on Runway 27 were initially uneventful. However, immediately after the main wheels made contact, the nose landing gear collapsed.
The failure caused the nose gear to fold rearwards, penetrating the forward fuselage and damaging the equipment bay. This structural breach allowed hydraulic fluid to leak into the aircraft, resulting in smoke and fumes filling the cockpit and cabin. The aircraft came to a halt approximately 500 metres from the touchdown point.
Following the engine shutdown, the loss of electrical power caused the passenger address system to fail. The crew ordered an evacuation, and all passengers and crew exited the aircraft. During the process, two passengers sustained minor injuries and were treated in hospital.
The investigation
The AAIB investigation focused on the structural failure of the nose landing gear. Examination of the nose gear main fitting revealed that the upper internal bore had developed fatigue cracks. These cracks originated from machining grooves within the bore surface.
Investigators found that while the component's records indicated the incorporation of a service bulletin intended to improve surface finish, the actual surface roughness was significantly higher than the permitted limit. This excessive roughness, combined with the presence of machining grooves, facilitated the rapid development of fatigue cracks.
Findings
- The nose landing gear main fitting failed due to the formation of multiple fatigue cracks in the upper section of the internal bore.
- These cracks originated at the base of machining grooves produced during manufacturing.
- The primary cause was the failure to properly implement a required improved surface finish during a previous overhaul, despite maintenance records claiming the work had been completed.
- The resulting high surface roughness significantly accelerated the fatigue process.
- The collapse caused the nose gear to penetrate the fuselage, leading to the release of hydraulic fluid and subsequent smoke in the cabin.