What happened
On 15 August 2014, a BAE Systems Jetstream 31, registration G-GAVA, was operating a scheduled commercial passenger flight from Belfast City Airport to Doncaster Sheffield Airport. The flight, carrying two crew members and one passenger, landed on Runway 20 at 1836 hrs under stable weather conditions.
Approximately eight seconds after touchdown, while the aircraft was decelerating at 65 kt, the left wing suddenly dropped. The left main landing gear detached from its mounts, causing the aircraft to yaw uncontrollably. The aircraft slid along the runway, with the left engine propeller and landing gear cylinder striking the surface, before veering off the runway onto the adjacent grass. The aircraft came to rest on its belly, the right landing gear, and the left wingtip. All occupants evacuated the aircraft without none injuries.
The investigation
The AAIB investigation examined the aircraft's flight data, cockpit voice recorder, and a preliminary inspection of the wreckage. Investigators focused on the structural integrity of the landing gear, specifically the forward yoke pintle. The investigation also reviewed the maintenance history of the gear, which had been overhauled in December 2012, and the implementation of a recent modification involving a protective washer.
Findings
- The left main landing gear failed because the forward yoke pintle housing fractured.
- The failure was initiated by stress corrosion cracking at the top outer edge of the forward yoke pintle.
- Evidence of rotational wear and corrosion pitting was found on the mating surfaces of the pintle housing.
- While a protective washer had been installed to prevent such issues, it was observed that the washer's position may have been compromised, potentially negating its protective effect and allowing for surface degradation.
- The landing parameters were within design limits, and the aircraft weight was well below the maximum permissible landing weight.
Safety action
- Safety Recommendation 2014-038: It is recommended that the EASA take action to ensure the continued airworthiness of Jetstream 31 main landing gear legs manufactured from DTD 5094 aluminium alloy that have embodied SB 32-JM7862.
- Safety Recommendation 2014-039: It is recommended that the EASA mandate an effective inspection regime for the Jetstream 31 to detect cracking and prevent failure of the yoke pintle on main landing gear legs manufactured from DTD 5094 aluminium alloy.