Incident Overview
The pilot of a single-engine aircraft received multiple weather briefings prior to departure. The briefings included information about a severe cold front and thunderstorms along the intended route. The pilot was advised that visual flight rules (VFR) flight was not recommended, but the aircraft departed nonetheless.
En Route Events
During the flight, the pilot reported that he was "totally obscured." Shortly thereafter, he experienced difficulty maintaining a heading and noted that his directional gyro and magnetic compasses were spinning. Radio and radar contact with the aircraft were lost soon after these reports.
Crash and Examination
The aircraft subsequently crashed in a wooded area. An examination of the vacuum pump revealed no evidence of preimpact failure. The directional gyro was disassembled and showed signs of wear in the upper and lower gimbal ring bearings. According to the examination, this wear could have resulted in erratic operation or excessive precession of the gyro.