Incident Overview
At night, the destination airport was unattended. The pilot received a weather briefing at 0519 CDT, but no current weather information was available. During arrival, air traffic control vectored the aircraft for an Instrument Landing System (ILS) approach to Runway 24. The pilot was advised that current weather information was still unavailable.
Approach and Missed Approach
Before reaching the outer marker (the final approach fix), the pilot stated twice that he was not receiving the ILS localizer. However, the aircraft, which was equipped with an Automatic Direction Finder (ADF), tracked back on course and crossed over the outer marker/localizer marker beacon. At 0801, the pilot was cleared for the approach and radar service was terminated. Approximately seven minutes later, the pilot declared a missed approach, after which radio and radar contact were lost.
Accident Location and Weather
The aircraft was found where it crashed about 1 mile southeast of the airport at an elevation of 3,575 feet. The airport elevation was 3,792 feet. Since the local altimeter setting was not available, the Roanoke setting was used; minimums for the approach were a 630-foot ceiling and 2 miles visibility. The 0810 weather report indicated, in part: 100 feet obscured and 1/8 mile visibility with fog.
Investigation Findings
An investigation revealed that the ILS localizer had tripped off for an unknown reason at some time before 0755 while the airport was unattended. The localizer was found to work correctly after being reset.