What happened
During an arrival procedure, the crew of USAir flight 499 opted to land on runway 24 because visibility met the requirements for that specific strip, whereas the previously planned ILS approach to runway 06 was not possible due to low RVR. The runway surface was covered in snow, and braking action was reported as ranging from fair to poor. During the landing roll, the Boeing 737 touched down significantly past the displaced threshold, estimated between 1,800 and 2,000 feet.
As the aircraft decelerated, the spoilers failed to deploy automatically despite being in the armed position, necessitating manual intervention by the captain. Although the crew utilized reverse thrust, braking, and lowered the nose, the brakes failed to stop the aircraft effectively. The plane continued down the runway, striking a runway end light and a fence before coming to a halt across a road. There were 23 occupants on board, including 1 injury and 22 people who remained uninjured.
Findings
Investigation into the accident identified several contributing environmental and operational factors. The approach was conducted with a quarterknot tailwind and at an airspeed approximately 10 knots above Vref, despite regulations prohibiting tailwind landings on runway 24 under slippery conditions. Key findings included the presence of snow, fog, and low ceilings, as well as the pilot's decision to proceed with the landing rather than performing a go-around. The overrun was further exacerbated by the failure to maintain an appropriate touchdown point and the aircraft's contact with runway infrastructure and terrain.