What happened
During the approach for landing, the crew was unable to achieve a down and locked indication for the nose gear. In an attempt to resolve the issue, the crew recycled the landing gear and subsequently utilized the alternate gear extension system. After receiving notification that the gear appeared to be extended, the crew proceeded to land. However, at the end of the landing roll, the nose gear collapsed. Additionally, the right main outboard tire experienced a blowout during the landing due to a frozen brake.
The investigation
The investigation determined that the nose-wheel well was susceptible to ice contamination. Specifically, the nose gear down lock plunger had frozen and could not extend into the down and locked position. It was found that slush had accumulated on the nose gear down lock at the departure airport and subsequently froze. Furthermore, the use of the alternate extension system resulted in the loss of 500 PSI of hydraulic pressure, which normally assists in maintaining the gear in the extended position.
Findings
At the departure airport, at least one inch of wet snow and slush had been reported on the runway 22 minutes prior to departure. US Airways procedures required that takeoff should not be performed if slush or wet snow in excess of 1/2 inch covered the runway. The investigation found that the acting station manager failed to follow company procedures, which required reporting such runway conditions to the dispatcher and the captain of the flight.