What happened
The pilot was cleared for a localizer and distance measuring equipment (DME) runway 15 approach to Ukiah Airport. At 1307 Pacific Daylight Time, the pilot initiated the approach at the Tucci intersection, located approximately 15.5 miles north of the runway. By 1311:04, radar contact indicated the aircraft was roughly 5 miles north of the airport.
At 1313, personnel at the Ukiah Flight Service Station requested the aircraft's position. The pilot reported being 5.5 miles on the DME, which corresponded to a location 5.5 miles north of the airport. No further communications were received from the aircraft. The aircraft subsequently crashed on rising mountainous terrain about 4 miles south of the airport at an elevation of 200 feet.
The investigation
An examination of the navigation equipment revealed a critical configuration error. The DME was selected to the number 2 navigation receiver, which was tuned to the Ukiah VOR. This VOR is located approximately 6 miles south-southeast of the airport. For the intended approach, the DME should have been selected on the number 1 navigation receiver, which was correctly tuned to the localizer/DME at the airport.
Findings
Weather conditions at 1324 at Ukiah included an overcast ceiling at 1000 feet with obscured skies, visibility of 1.5 miles, light rain, and fog. The wind was from 130 degrees at 8 knots. The misselection of the navigation receiver led to incorrect distance information, contributing to the controlled flight into terrain.
Safety message
Pilots must verify that all navigation receivers are correctly tuned and selected for the specific approach being flown, particularly when multiple navaids are in proximity.