What happened
On July 24, 1971, an international cargo flight operating from San Francisco to Saigon, with scheduled stops in Honolulu, Guam, and Manila, was conducting its final leg from Guam. The initial portions of the journey through Honolulu and Guam proceeded without incident. At approximately 21:25 GMT, the aircraft departed Guam for Manila.
During the approach to Manila, the flight established contact with Manila Control at 00:00 hours, receiving updated meteorological data. After being transferred to Manila approach control, the crew received instructions for a VOR/DME approach to Runway 24 via the Bangbang Intersection, along with weather reports indicating light rain and moderate visibility.
The aircraft began its approach sequence at approximately 00:19 hours. By 00:21 hours, the flight reported being at 22 DME, descending from 5,000 feet to 4,000 feet. Shortly after reporting an altitude of 4,200 feet, communication between the controller and the aircraft was lost.
Investigation revealed that at roughly 00:23 hours, the Boeing 707 (implied cargo flight) struck Mt Kamunay, located approximately 20 miles ENE of the Manila VOR, at an altitude of 2,525 feet. Local witnesses reported hearing an aircraft followed by a series of explosions. The impact resulted in the total destruction of the aircraft and 4 fatalities among the crew.
Findings
Official investigations concluded that the accident was caused by improper crew coordination, which led to the aircraft descending prematurely. The flight was operating nearly 1,000 feet below the required minimum altitude of 7,000 feet at the 23 DPB waypoint. This error occurred because the pilot-in-command misinterpreted ambiguous communications from the co-pilot regarding the aircraft's position and the intended descent profile.