Piper AEROSTAR 602P N301FW accident near Reno, Nevada

Probable cause

The failure of the left main landing gear to fully extend for reasons that could not be determined because postaccident examination and testing did not reveal any evidence of preimpact mechanical failures or malfunctions that would have precluded normal operation.

NTSB analysis

The airline transport pilot reported that, nearing the airport at the conclusion of a personal cross-country flight, he performed the before landing checklist. When he extended the landing gear, he noted that only the nose and right main landing gear (MLG) lights were illuminated, which indicated that the left MLG was not locked in the extended position. He then climbed and performed the emergency gear extension checklist, but the left MLG still did not extend. The pilot chose to continue flying to exhaust the fuel in the left tank before attempting to land. During landing, the airplane sustained substantial damage to the left wing and impacted two taxiway signs before coming to rest. A witness reported that it appeared that the left-side tire was sitting against the inside gear door and not fully extended.

The pilot reported that the accident flight was the first flight after a recent owner-assisted annual inspection, during which the left landing gear control valve was resealed with new "O" rings. Postaccident examination of the airplane revealed that the right MLG side brace was broken, which would prevent gear retraction. During a partial gear-swing test, the MLG gear started to retract; however, immediately thereafter, the left side push-pull rod assembly that connected the gear door actuator to the MLG and door control valve failed and broke in half, likely due to impact damage.

The push-pull rod and control valve were subsequently examined, and there was no evidence of any preimpact mechanical failures or malfunctions that would have precluded normal operation. The reason for the failure of the left MLG to fully extend could not be determined.

Text from the NTSB. Open the NTSB docket for WPR17LA076 for the full record.