Cessna T210K N727FA accident near Midland, Texas

Probable cause

The failure of the right main landing gear to fully extend before landing due to a bent downlock adjustment screw.

NTSB analysis

The pilot realized that the right main landing gear failed to extend before landing; they followed the emergency checklist procedure to manually pump the gear down. However, the pilot was unable to extend the gear, and the right main landing gear collapsed upon landing. When the airplane was recovered, the right gear was locked in the extended position, and the airplane was towed to a hangar and placed on jacks. The landing gear was then cycled successfully numerous times; the right main landing gear's failure to extend could not be duplicated. Further examination revealed that the top end of the right main landing gear's downlock adjustment screw was slightly bent. When the bent screw was positioned so that it leaned against the landing gear's downlock mechanism during the extension cycle, the landing gear system's downlock engaged before the gear was fully seated in the gear saddle. The position of the adjustment downlock screw was not documented until after the landing gear had been cycled several times; however, the condition is consistent with the pilot’s inability to manually extend the landing gear using the emergency hand pump. No other mechanical anomalies were noted, and the landing gear system operated normally after the adjustment downlock screw was replaced. It is unknown how the downlock adjustment screw got bent or how long it had been in that condition.

Text from the NTSB. Open the NTSB docket for CEN12LA300 for the full record.