Incident Overview
During a night arrival, the pilot contacted approach control, located in the control tower, and received vectors for an ILS runway 6 approach. During the first approach, the radar controller observed that the airplane drifted left of course and descended below the glideslope. This resulted in a low-altitude aural alarm, and the radar controller issued a low-altitude alert. The pilot executed a missed approach and stated that he 'had a mismatch of the two compasses.'
Second Approach Attempt
The pilot was vectored for a second approach and instructed to maintain 3,000 feet until established on the approach. The pilot was then transferred to tower frequency and cleared to land. About six miles from the runway, the airplane again drifted left of course, and another low-altitude alert was activated. The tower controller stated that he did not hear the low-altitude aural alarm because he was focused on another airplane that was landing. A supervisor controller, situated on the other side of the control cab, heard the alarm and prompted the tower controller to take remedial action.
Final Moments
The airplane crashed into an open field outside the outer marker in a wings-level attitude. Impact occurred at an elevation of 1,500 feet. The ILS glideslope crossing altitude at the outer marker was 2,800 feet.
Investigation Findings
The extent of the reported compass mismatch was not verified. No preimpact mechanical malfunction of the airplane was found. The pilot had flown nine instrument approaches since receiving an instrument competency check on April 27, 1995, and had logged 15.7 hours of night flight time.