On May 30, 2004, a Cessna T210M (registration N121JR) was involved in an aviation accident near Santa Rosa, CA. Investigators recorded the probable cause as: Maintenance personnel's improper installation and servicing of a retaining ring, which resulted in the failure of the landing gear door actuator and failure of the landing gear extension system during landing. This summary draws on records from the U.S. National Transportation Safety Board (NTSB) historical archive.
Aircraft registered N121JR. Photo: Jeroen Stroes Aviation Photography from Netherlands / CC BY 2.0, via Wikimedia Commons
A single-engine airplane sustained damage after landing with main gear retracted due to a failed main landing gear door actuator, which had been worked on 10.7 hours prior. The retaining clip was improperly installed.
Incident Overview
A pilot experienced a landing gear malfunction while attempting to land. The main landing gear would not extend, and the landing gear down-and-locked light did not illuminate. The hydraulic motor continued running, and the hydraulic fluid reservoir was adequately filled. After performing all recommended emergency procedures for landing gear malfunctions without success, the pilot executed a landing with the nose landing gear extended and the main landing gear only partially extended.
Landing and Runway Excursion
During the landing, the airplane tilted and drifted to the left of the runway, ultimately impacting a sign. The aircraft came to rest with the main landing gear retracted.
Post-Accident Examination
A post-accident examination of the landing gear system revealed that the right main landing gear door actuator had failed. The retaining clip on the actuator was installed improperly. The failed actuator had been worked on 10.7 hours prior to the accident.
