1977 United Airlines Flight 2860 Mountain Crash in Utah (N8047U)

Accident Overview and Immediate Sequence of Events On December 18, 1977, at approximately 0138:28 Mountain Standard Time, a United Airlines, Inc. DC-8F-54 cargo aircraft operating as Flight 2860 struck a mountain in the Wasatch Range near Kaysville, Utah. The aircraft was destroyed, and the three flightcrew members, who were the only people aboard, were killed. During its descent and approach to Salt Lake City Airport, Flight 2860 experienced electrical system problems. The crew requested a holding clearance, which was issued by the approach controller and accepted by the flight crew. The flight then asked to leave the approach control frequency for a short period to contact company maintenance, and that request was granted. ## Loss of Communication and Terrain Encounter Flight 2860 remained off the approach control frequency for 7.5 minutes. While absent from the frequency, the aircraft entered an area near hazardous terrain. The approach controller became aware of the flight’s difficult position but could not reach the crew. When Flight 2860 returned to the approach control frequency, the controller advised the crew that the aircraft was too close to terrain on its right and instructed it to make a left turn. After the controller repeated the instruction, the flight began a left turn. About 15 seconds later, the controller told the flight to climb immediately to 8,000 feet. Eleven seconds after that, the flight reported it was climbing from 6,000 feet to 8,000 feet. The aircraft then crashed into a 7,665-foot mountain near the 7,200-foot level. ## Official Probable Cause and Contributing Factors The official investigation attributed the accident to the approach controller’s issuance and the flight crew’s acceptance of an incomplete and ambiguous holding clearance, combined with the flight crew’s failure to follow prescribed impairment-of-communications procedures and prescribed holding procedures. The report stated that the controller’s and flight crew’s actions were attributed to probable habits of imprecise communication and imprecise adherence to procedures developed through years of exposure to operations in a radar environment. A contributing factor was the failure of the aircraft’s No. 1 electrical system for unknown reasons.