Piper PA-24-260 N9267P accident near San Jose, California

Probable cause

A landing gear collapse due to an inadequately maintained landing gear extension and retraction system.

NTSB analysis

The pilot reported the takeoff and flight were uneventful. During the landing approach, the landing gear did not extend. After performing a series of troubleshooting steps with no success, the pilot decided to return to his home airport and perform a manual gear extension. During the return flight, the manual gear system appeared to be jammed, so he continued to troubleshoot and performed a series of high-G maneuvers to help the gear extend. After multiple attempts the landing gear extended; however, the gear indication system did not show the gear was locked in the down position. The pilot continued with the landing, which was uneventful, until he retarded the throttle during the landing roll and the nose gear and main gear retracted.

Postaccident examination revealed that the landing gear extension motor would intermittently seize, often without tripping its circuit breaker. Because the airplane was equipped with an emergency gear extension system, this event alone should not have been cause for concern, and the pilot followed the correct procedures to resolve the problem. However, the manual emergency gear extension system was also jammed because of significant wear to its release arm. Additionally, due to a worn and out of adjustment nose gear drag link assembly, even when the pilot was able to force the gear down with the manual system, it did not lock in place. Due to the design of the system, this out of adjustment condition was masked by the landing gear motor transmission, which under normal operation drove the drag links into the locked position.

An airworthiness directive had been issued to resolve the gear collapse issue following manual extension, and this appeared to have been completed and was not due at the time of the accident. Even though it was not due, the wear observed to multiple landing gear components should have warranted further examination and repair by maintenance personnel during the annual inspection, which was completed one week before the accident.

Text from the NTSB. Open the NTSB docket for WPR23LA116 for the full record.