Incident Overview
A Boeing 727-200 experienced a malfunction during taxi, resulting in minor damage to the aircraft. The left main landing gear side strut separated from the main shock strut during the taxi operation.
Examination Findings
Inspection of the right main landing gear revealed that the side strut assembly had also separated from the main shock strut, and the gear door was open. The threaded portion of the main strut attachment clevis was separated from the side strut assembly, while the clevis remained attached to the main shock strut. The clevis bolt was found to be dry and corroded, with broken and stripped threads. No evidence of lubrication was present on the clevis bolt. The retaining nut and lock nut inside the lower end of the side strut were also dry and corroded, showing corresponding damaged and stripped threads inside the lock nut.
Metallurgical Analysis
Metallurgical examination determined that the threads had suffered severe corrosion damage prior to being stripped.
Manufacturer's Response
The aircraft manufacturer stated that a redesign for the side strut assembly was in development to block moisture ingress, prevent corrosion, and improve lubrication for the assembly.