Incident Overview
At 0834 Eastern Standard Time, a pilot departed Bradford Airport on an instrument flight rules (IFR) flight destined for Alton, Illinois. Approximately four minutes after departure, the pilot advised air traffic control that he was encountering difficulties with his flight instruments while operating in IFR conditions.
Flight Details
The pilot attempted to return to the departure airport using directional finder (D.F.) steers but was unable to do so. He then contacted Cleveland Center and was cleared to climb to 8,000 feet mean sea level (MSL). The center recommended that the pilot proceed to Toronto, Canada, which had the nearest airport with acceptable weather conditions. However, the pilot reported being unable to control his altitude and heading, and subsequently entered a dive and crashed.
Instrument Failure
Post-accident examination revealed that the horizontal situation indicator (HSI), directional gyro, and turn coordinator were pneumatic pressure instruments that all operated from the same system. The pneumatic pressure system incorporated two pressure pumps, one on each engine. Inspection of the pumps found that both pump drives had sheared. Radio calls from the pilot had indicated that all pressure instrument readings were faulty.
Weather Conditions
At the time of the incident, weather conditions included turbulence, low ceiling, and snow.