Incident Overview
During touchdown, the left main landing gear spring assembly failed. Post-incident examination of the failed component disclosed a low cycle fatigue failure mode, but with no clear point of origin identified. The pilot had recorded approximately 200 landings since the last annual inspection.
Historical Service Note
In 1974, Schweizer Aircraft Corp issued a service note that defined the failure conditions and outlined inspection procedures for the landing gear spring assembly. The fracture analysis identified classical failure properties that were described in that service note.
Component Examination
The fractured spring assembly was examined to determine the nature of the failure. The analysis confirmed a low cycle fatigue mechanism, consistent with the properties detailed in the 1974 service note. However, no distinct initiation point could be pinpointed on the fracture surface.
Operational Context
At the time of the incident, the aircraft had accumulated roughly 200 landings since its last annual inspection. No further operational details or maintenance history were provided in the investigation report.