Approach and Descent
The pilot of N55YS was cleared for a Localizer Runway 31 approach at Columbia Owens Downtown Airport in Columbia, South Carolina. Radar data showed that the aircraft crossed the HIDEE intersection at 1,300 feet msl, which was 500 feet below the published minimum crossing altitude. The Minimum Safe Altitude Warning system activated and displayed a recurring "LA" low altitude alert on the north radar controller's screen, but no safety alert was issued to the pilot.
Missed Approach
The pilot informed the north radar controller that he was executing a missed approach. Instead of following the published missed approach procedure, he initiated a right turn. The minimum descent altitude for the approach was 660 feet, but the aircraft's recorded altitude was 400 feet. The north radar controller instructed the pilot to climb and maintain 2,100 feet and advised him to remain on the localizer and not stray too far north. The pilot acknowledged these instructions.
Subsequent Approach
Weather information was provided for Columbia Metropolitan Airport, and vectors were given for the ILS Runway 11 approach. The pilot was cleared for the ILS Runway 11, four miles from the outer marker, and told to maintain 2,100 feet until established. The decision height for this approach was 436 feet. Radar data indicated that the aircraft crossed the outer marker at 1,700 feet. Low altitude alerts were observed on radar playback for the remainder of the approach, and the north radar controller did not issue any safety alerts. The final low altitude alert was recorded at 300 feet, one mile from the runway end.
Radio Communications
The pilot was instructed to contact the tower and acknowledged. After transferring communications, the local controller was unable to establish radio contact with N55YS. The local controller made multiple transmissions including a low altitude alert, clearance to land, weather information, runway visual range, and position correlation, but received no response. Non-ATC recordings revealed that the pilot did respond to these transmissions, but his radio calls on the local control frequency were not heard by the controller nor recorded by the ATC facility. No further contact was established, and the radar track eventually entered coast mode.
Final Events
The aircraft was located the following morning about one mile west of the runway in a wooded area. Examination of the airframe, flight controls, engine assembly, and accessories found no evidence of a pre-crash mechanical failure or malfunction. Inspection of the flight instruments revealed no anomalies. There was no logbook entry indicating a current altimeter test.