Swearingen SA227-AC N3108B incident near Williston, North Dakota

Probable cause

The snowplow driver’s failure to ensure that the runway was clear before driving onto it, which resulted in a runway incursion with a departing airplane.

NTSB analysis

The pilot reported that he made several radio calls announcing his intention to take off and that he did not hear any radio calls from other aircraft or vehicles. At the end of the ground roll, he heard a "garbled" transmission stating something about the departure runway. He stated that, as the airplane lifted off, he saw a snowplow on the runway heading in the opposite direction. He continued the takeoff and flew over the snowplow. The snowplow driver stated that he did not hear any radios transmissions from the airplane until after it was airborne and that he had been plowing for about 30 minutes and had made radio calls every 2 to 3 minutes announcing his position. Another pilot who landed about 30 minutes after the incident reported that he also saw a snowplow operating on the airport and that he did not hear any radio calls from the snowplow even after it had crossed a runway. A postincident check of the snowplow and airplane radios revealed that they were functioning properly. The reason why the pilot and snowplow driver were not aware of each other's presence could not be determined due to the lack of recorded radio transmissions and because the airplane and snowplow radios were functioning properly. However, Federal Aviation Administration guidelines to ground vehicle operators state that they need to yield right-of-way to moving aircraft and that they need to ensure that no potential conflict with a moving aircraft exists.

Text from the NTSB. Open the NTSB docket for CEN13IA107 for the full record.