What happened
The flight was conducting an approach for landing when weather conditions included blowing snow, as reported by the Automatic Terminal Information Service (ATIS). The crew initially acquired visual reference with the ground and approach lights at approximately 200 feet above ground level. This was followed by a visual sighting of the runway. Because the ATIS had reported blowing snow, the crew anticipated seeing snow on the runway and was not surprised when they observed snow blowing across the runway about 2,000 feet beyond the threshold.
As the aircraft continued its descent, approximately 2,200 feet down the runway, it entered a dense cloud of snow. In these conditions, the right wing struck a large snow sweeping vehicle. The vehicle was traveling in the same direction as the aircraft and was positioned to the right of the runway centerline. The impact caused the aircraft's right wing to separate from the fuselage. Following the collision, the aircraft swerved off the runway.
The investigation
Investigations into the air traffic control procedures revealed significant communication gaps. Neither the approach controller nor the local controller advised the flight of ongoing snow removal operations. Furthermore, the local controller did not communicate with the snow sweeper after taking over responsibility for the flight from the approach controller. The local controller stated that he was unaware of the snow sweeper's location when he cleared the flight to land.
Findings
The primary contributing factors involved the interaction between the aircraft and ground equipment during low-visibility conditions. The crew's expectation of seeing snow did not prevent the collision because the specific location of the snow removal vehicle was unknown to air traffic control. The lack of coordination between controllers and ground vehicles created a hazardous situation where the aircraft was cleared to land without knowledge of obstacles on the runway.