Narrative:United Flight 615 departed Boston at 17:32 EST, made scheduled stops at Hartford, Connecticut, and Cleveland, Ohio, and arrived at Chicago, Illinois, at 21:59 CST. The flight departed Chicago at 22:59 CST. At 03:54, while approaching the Oakland area, Flight 615 was cleared to the Newark, California fan marker, with instructions to descend to 6,000 feet, maintain that altitude, and contact Oakland Approach Control over Altamont. At 04:11, the flight reported over Stockton, California, at 9,500 feet, descending. Five minutes later they were over the Altamont Intersection. The flight was cleared by Approach Control to the Oakland radio range station to maintain at least 500 feet above the tops of the clouds. The pilot followed this contact with a request for clearance direct to Newark and a straight-in range approach. This request was granted, with instructions to maintain an altitude of 500 feet on top of the cloud layer between Altamont and Newark. At 04:25 Flight 615 was cleared for a straight-in approach on the southeast course of the Oakland radio range from Newark. At 04:27 the flight reported leaving Newark inbound to Oakland. This was the last radio contact. The aircraft descended until it struck rising mountainous terrain at 983 feet MSL, 26 feet below the crest of the hill and approximately three miles to the right of the southeast on-course signal of the Oakland radio range. The major portion of the structure hurtled over the top of the knoll, scattering on the down-slope and into a canyon beyond. The captain was possibly using the ADF, allowing the DC-6 to be 3 miles to the right of the intended course and about 2500 feet below the 3500 feet minimum altitude. Cloud base was at 1500 feet with patches of fog obscuring terrain.
Probable Cause:PROBABLE CAUSE: "The failure of the captain to adhere to instrument procedures in the Newark area during an approach to the Oakland Municipal Airport."
Controlled Flight Into Terrain (CFIT) - Mountain
» Aviation Disasters / D. Gero
» CAB File No. 1-0058
Follow-up / safety actions
United Air Lines required crews to operate under IFR when above an overcast.