Accident Overview
The aircraft crashed on a wheat field during a night instrument training flight. The pilot had declared a vacuum system failure approximately 40 minutes after takeoff but declined ATC assistance for a no-gyro approach to Columbus. Two minutes after the radio call, radar contact was lost.
Radar Data
Radar data disclosed erratic heading and airspeed changes during the last minute of flight.
Post-Crash Investigation
During the post-accident investigation, each of the instruments was found to contain a suction cup. However, no evidence of failure or malfunction of the vacuum system was found. The aircraft had also been modified with a standby vacuum system for use in an emergency after failure of the primary system. Only pieces of the standby system were found due to the destruction of the aircraft, but the available evidence showed no signs of malfunction or failure. Suction cups, like the one found, are used by instructors to cover instruments for partial panel training.