Primary finding
Probable cause
Failure of the company station manager to follow proper dispatch procedures, and ice accumulation on the nose gear locking mechanism. Factors related to the incident were: wet snow (slush) on the runway at the departure airport, and inadequate design which allowed ice to render the nose gear downlock system inoperative.
Investigator assessment
Analysis narrative
Down & locked indication of nose gear was not achieved for landing. Crew recycled gear, used alternate gear extension system & made a fly-by. After being told gear appeared to be extended, crew landed, but nose gear collapsed at end of landing roll. Right main outboard tire also blew-out during landing due to frozen brake. Investigation revealed nose- wheel well was susceptible to ice contamination. Nose gear down lock plunger was frozen & would not extend to down & locked position. At departure airport, slush had accumulated on nose gear down lock & froze. Use of alternate extension system would have dumped the 500 psi hydraulic pressure that normally assisted in holding gear in extended position. Usair procedures stated that takeoff should not be made if slush or wet snow in excess of 1/2 inch covered runway. At least 1 inch of wet snow & slush was reported on departure runway, 22 minutes before departure; however, acting station manager did not follow usair procedures that required reporting this to dispatcher & captain of flight.
Source record
Factual narrative
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