Incident Overview
During an arrival, an aircraft was vectored to intercept the ILS Runway 27 localizer before reaching the MUNCI initial approach fix (IAF), located 21.5 miles from the runway. The air traffic controller instructed the pilot to maintain 4,000 feet until established on the localizer, then cleared the aircraft for the approach.
Approach Sequence
From the IAF, the minimum altitude on the approach was 3,700 feet until intercepting the ILS glide slope at the Picture Rocks NDB, which served as the final approach fix. The NDB was 9.4 miles from the airport, and the outer marker was 4.8 miles from the runway.
Communication
As the pilot continued the approach, he reported that his instruments indicated he was on the glide slope at 2,700 feet, but that he was still flying inbound toward the NDB. The controller responded by warning that the aircraft should be at 3,700 feet until reaching the NDB and repeated the altimeter setting.
Subsequent Events
Shortly after this exchange, the controller lost radio contact with the aircraft. The aircraft crashed near the top of a hill in wooded terrain at an elevation of approximately 2,400 feet, about 9 miles before reaching the NDB.
Investigation Findings
An examination of the aircraft's navigation equipment revealed that it was properly set. No preimpact malfunction or failure was found. The ILS system was flight checked and determined to be operating normally.