Watertown

The pilot landed at Watertown, loaded and off-loaded cargo, and departed without getting out of the airplane. A witness reported seeing the airplane over the runway at an altitude of about 50 feet agl. The airplane was described to be bouncing and buffeting. Another witness reported the weather as overcast with occasional snow flakes. The airplane then descended, impacted the terrain and exploded. Post accident inspection revealed a 1/2 to 3/4 inch thick ridge of rime ice along the leading edge of the left horizontal stabilizer. Pieces of arc shaped ice were located along the wreckage path. Inspection of the wreckage failed to reveal any preimpact failure/malfunction of the engine or airframe which would have prevented flight.

During descent into Billings, the Citation was sequenced behind a Boeing 757, and both airplanes were eventually cleared for visual approaches. About 1-1/2 mile from the runway the Citation was observed to roll rapidly to the inverted position and descended almost vertically into the ground. According to ATC transcripts and the airplane's cockpit voice recorder, the crew of the Citation had maintained visual awareness of the position of the B757 throughout the approach. At the time of the upset, the vertical separation between airplanes was 600 - 1,000 feet, and the horizontal separation was decreasing below 2.6 miles. One of the Citation captain's last comments was 'almost ran over a seven fifty seven.' Winds were 5 knots. All eight occupants were killed.

Just after liftoff, while climbing, the airplane struck a flock of birds (13 inland seagulls). Both engines flamed out and the airplane lost speed and height. The right wing stalled and struck an installation approach light on T-bar before the airplane crashed in flames 150 meters further. All six occupants were injured and the aircraft was destroyed.