What happened
While stopped on the runway awaiting takeoff clearance, the aircraft experienced a collapse of the left main landing gear bogie. The incident occurred while the aircraft was stationary and not in active flight.
The investigation
A post-incident examination of the landing gear assembly revealed that the aft bogie swivel joint lugs had failed. Investigators determined that the failure was caused by stress corrosion cracking.
The investigation found that the swivel joint lacked proper lubrication, a component necessary to keep water out of the mechanism. This lack of lubrication allowed corrosion to form on the surface of the lugs, which subsequently led to crack initiation at the corrosion pits.
Maintenance requirements for the operator specified that the swivel joint should be lubricated during every weekend check and every 'A' check. While the work cards for these inspections included narrative instructions for lubricating the bogie pivot joint, they directed the technician to locate the swivel joint by referencing a specific number on an illustration rather than explicitly naming the component.