What happened
On 15 August 2014, a BAE Systems Jetstream 31, registration G-GAVA, was performing a scheduled commercial passenger flight from Belfast City Airport to Doncaster Sheffield Airport. The flight, carrying two crew members and one passenger, proceeded normally through departure, cruise, and approach.
Upon touchdown on Runway 20 at 1836 hrs, the aircraft was within design landing parameters. However, approximately eight seconds after the wheels touched the ground, the left wing dropped abruptly. The aircraft began to yaw left, and the pilot lost directional control via the rudder and nosewheel steering. The left main landing gear detached from its mounts, causing the aircraft to slide along the runway on its remaining gear, wingtip, and luggage pannier. The aircraft eventually veered off the runway and came to rest on the adjacent grass. All three occupants evacuated the aircraft without injury.
The investigation
The AAIB investigation examined the aircraft's flight data, cockpit voice recorder, and terrain awareness system. Investigators performed a preliminary inspection of the accident site and the aircraft's wreckage. The examination focused on the left main landing gear, which had broken away from its trunnions. Metallurgical analysis of the fracture faces revealed that the failure originated at the top outer edge of the forward yoke pintle. The investigation also reviewed the maintenance history of the landing gear, which had been overhauled in late 2012 and had undergone recent inspections and modifications.
Findings
- The primary cause of the landing gear failure was stress corrosion cracking in the forward yoke pintle.
- The failure was likely triggered by rotational wear on the forward face of the yoke pintle housing, which degraded the protective surface treatment.
- Evidence suggested that a protective washer, installed to prevent such corrosion, may have rotated out of position, thereby negating its protective function.
- The aircraft's landing parameters, including weight and descent rate, were within safe design limits.
- The investigation noted that the same aircraft, under a different registration, had experienced a similar right-side gear failure in 2012 due to similar corrosion issues.