Overview
On 1 July 1966, the wreckage of Flight 785 was discovered at 2,300 feet above mean sea level in a ravine on the northern slope of Mount Rabangan (elevation 3,500 feet). The aircraft was en route from Mamburao, where it had made an intermediate stop, to San Jose. The flight had departed Manila at 1030 hours local time and arrived uneventfully at Mamburao. It departed Mamburao at 1204 hours.
Sequence of Events
At 1215 hours, Flight 785 requested terminal weather information from San Jose Radio Station. The station transmitted the requested information, but the flight did not acknowledge. A witness reported seeing an aircraft flying at very low altitude toward the mountain on a heading of approximately 065°. Shortly after, the witness heard a loud explosion emanating from the mountains east of his position. Subsequent attempts by San Jose Radio Station to contact the flight on VHF and HF frequencies were unsuccessful.
Wreckage and Injuries
Investigators found the wreckage in the afternoon on 1 July 1966. Two passengers were seriously injured; the other 26 occupants were killed. The accident site was approximately 10 nautical miles inland, midway between Mamburao and San Jose.
Weather Conditions
At the time the aircraft was observed over Sablayan, the sky condition was described as low, thick, dark clouds with strong wind and heavy rain. The actual weather near the crash site was substantially similar to the forecast that had been conveyed to the pilot by the dispatcher during the pre-flight weather briefing. Thirteen minutes after take-off from Mamburao, the pilot encountered instrument meteorological conditions while operating under a VFR flight clearance.
Probable Cause
The Board determined that the probable cause of the accident was misjudgment of terrain clearance, which resulted in collision with trees. Contributing factors included the instrument meteorological conditions en route, accompanied by severe turbulence and strong gusty winds over the crash site.