What happened
During the landing roll following touchdown, the flight crew of a commercial passenger jet noticed a vibration that grew more severe as the aircraft decelerated. This was followed by the airplane tilting and yawing to the left. The pilot-in-command responded by applying rudder and braking, eventually bringing the aircraft to a stop near the center of the runway.
The investigation
An examination of the left main landing gear (MLG) determined that the upper torque link had failed. This failure allowed the sliding strut to pivot, which led to the subsequent separation of both wheels on the left main landing gear.
A tolerance check performed on the upper and lower torque links revealed that the clearances for the clevis lug and the pintle pin were out of specifications. Additionally, investigators observed several small fatigue cracks in the area surrounding the torque link fracture.
Maintenance records indicated that inspection criteria required the MLG and its tolerances to be checked every 1,150 hours during a 'B' check; the most recent inspection of the left MLG had taken place 475 hours before the accident. Furthermore, aircraft records showed a recent history of landing gear vibrations.