Aircraft Accident/Incident Report

Tooele, Utah 84704
Wednesday, March 7, 2007 21:35 MST

The airplane broke apart in flight while the pilot was maneuvering at cruise altitude. A witness in another airplane, who was 4 to 5 miles in trail of the accident flight at the same altitude, clearly saw the strobe lights of the accident airplane in front of him. The witness climbed to 9,500 feet and encountered what he described as cumulonimbus clouds and light icing. He stated that the temperature was 32-34 degrees Fahrenheit. He descended to 7,500 feet where he encountered severe turbulence, which caused him to hit his head violently against the cabin ceiling. He observed that he was below the accident airplane, and estimated that it was at 8,500 feet. He then lost sight of it. Radar data indicated that the accident flight turned left, and then began a descending right turn. The airplane broke apart during the turn. The fracture surfaces indicated a positive overload condition on all separated wing and tail components, with significant permanent set deformation of major structural elements in the wings and tail observed. A metabolite of diazepam (a prescription anti-anxiety medication commonly known by the trade name Valium), was found in the pilot's kidney and liver on toxicology testing. The pilot had a prior history of anxiety and depression that was treated with medication, though he had reportedly not received any recent medical treatment or medication. No blood or urine was available for analysis, so it is not possible to estimate when in the previous days or weeks that diazepam might have most recently been used or to determine the relevance, if any, of the medication or the condition for which it was used.

The pilot exceeded the design stress limits of the airplane, which resulted in the in-flight separation of the wings and horizontal stabilizers. Contributing to the accident were the night lighting conditions, clouds, turbulence and icing conditions.