What happened
While operating under instrument conditions, the pilot of Airspur 8773 requested to hold north of the VOR at 12,000 feet msl to wait for improved weather. At the time, visibility was reported at 1.75 statute miles with a 200-foot overcast ceiling. During the holding pattern, the pilot reported encountering light rime icing.
Following the hold, the aircraft was cleared for a VOR instrument approach. Witnesses observed the aircraft type on the downwind leg at approximately 500 feet altitude. Shortly after, an observer noted a sudden increase in engine power, describing a sensation similar to a propeller pitch reversal. Multiple witnesses then observed the plane emerge from the clouds performing a series of sharp, alternating banks before rolling inverted. The aircraft struck a highway south of the airport perimeter, slid down an embankment, and ended up partially submerged in a lake. At the time of the accident, heavy snow was falling and the roadway was covered in slush.
Findings
An examination of the wreckage showed the flaps were set to 30 degrees, the wing deice boots were ribbed, and the inertial separator was in the open position. Toxicological analysis of the pilot's blood and urine revealed the presence of several substances, including the antidepressant sertraline, the antihistamine chlorpheniramine, the decongestant pseudoephedrine, and acetaminophen. The presence of these medications, particularly the psychotropic antidepressant, is noted as a disqualifying factor under aviation medical guidelines. The use of chlorpheniramine and pseudoephedrine is associated with potential side effects such as drowsiness, dizziness, and impaired coordination.