What happened
The aircraft had initially returned to the airport for a precautionary landing after the crew noted excessive vibration from the number four engine ten minutes into the flight. Upon arrival, the aircraft touched down with approximately 4,000 pounds over the maximum allowable landing weight limit. Following the landing, maintenance personnel examined the affected engine. After determining the issue was resolved, the aircraft was released for further flight operations.
An exchange of pilot in command occurred before the aircraft began taxiing for takeoff. During this taxi phase, the nose gear assembly failed and collapsed. The incident resulted in significant damage to the landing gear structure.
The investigation
Post-incident examination of the aircraft revealed that the nose gear assembly had suffered an overload failure. The investigation determined that the structural integrity of the nose gear was compromised due to excessive stress during the taxi maneuver.