Accident Summary
An aircraft on a flight to Chadron, Nebraska, via the Chadron VOR crashed into trees on a ridge during an attempted NDB approach. The accident occurred in dark night conditions with low ceiling, fog, and light snow. The passenger sustained serious injuries, and both pilots were killed.
Narrative
The flight was proceeding toward the Chadron VOR. Approximately 30 miles south-southeast of the VOR, the pilot requested and received clearance to fly direct to the Ackme Initial Approach Fix (IAF) for an NDB runway 02 approach. The Ackme IAF was located 9 miles southwest of the airport on a bearing of 227°, defined by the intersection with the 356° radial of the Chadron VOR. The NDB itself was at the airport. The aircraft continued toward the VOR, which was in the same general direction but situated 11.9 miles south of the Ackme IAF.
About 3 to 4 miles southeast of the VOR, radar service was terminated and a frequency change was made. Shortly thereafter, the aircraft struck trees on a ridge and crashed. The initial impact occurred in wings-level flight at an elevation of approximately 4,480 feet, on a direct route between the VOR and the Ackme IAF.
Investigation Findings
Post-accident examination revealed no preimpact part failure or malfunction. Radar data indicated that after the frequency change, the aircraft continued to the VOR and then maneuvered as if the pilot was flying the NDB approach but using the VOR as the IAF. Radar contact was lost after the aircraft performed a procedure turn and was outbound about 6 miles northeast of the VOR. The crash site, however, was located approximately 3 miles west-southwest of the last radar contact point.
The reported weather at Chadron included an overcast ceiling at 500 feet, visibility of 1.5 miles, light snow, and fog. No other significant weather was reported.
The official probable cause findings listed the following factors: dark night conditions; low ceiling; fog; snow; improper IFR procedure by the pilot; discontinued planned approach; failure to maintain proper altitude; high terrain; and trees.