The aircraft was a
Douglas DC-3 manufactured in the United States and had its first flight in 1944, registered as 43-16107, before being delivered to
Philippine Airlines and re-registered as PI-C17. It had an airworthiness certificate valid until July 18, 1966. The aircraft underwent an airframe and engine check about 9 hours before the crash. Maintenance records showed that due to mechanical defects, the left propeller assembly was changed thrice between February and June 1966, and the right propeller assembly was changed twice during the month of May 1966. 4 days before the accident, the co-pilot's altimeter was found to be indicated lower than the captain's altimeter on the same settings. Despite the altimeter errors, the aircraft was released for scheduled operations until it was replaced on June 27. It was equipped with two
automatic direction finders and a
VOR rating it suitable for IFR flights. The aircraft's center of gravity was within allowable limits.
Crew The captain (35) held an airline pilot's license with instrument ratings on the
Douglas DC-3 and
Hawker Siddeley HS 748. His records indicated that he was scheduled for a route qualification check on the Manila-Mamburao-San Jose route in September 1965, however because
Mamburao Airport was closed for operations at the time, it was redirected to Lubang. He had flown this route four times between January and June 1966, and had flown a total of 4,240 hours. His medical certificate showed no waivers or limitation, and was valid until the end of August 1966. The first officer (29) held a commercial pilot's license with instrument ratings on the DC-3 and light aircraft. As of August 1965 he flew a total of 1,777 hours. His medical certificate also showed no waivers or limitation, and was valid until August 1966. There was also another observer pilot (21) who acquired a student pilot license on October 8, 1964, but also acquired a commercial pilot's license by the
FAA on single-engine aircraft. He applied for a commercial pilot's license in January 1966 however he didn't meet the requirements for qualification yet. As of February 1966 he flew a total of 181 hours on light aircraft.{{Cite web |title=Final Accident Report regarding PI-C17 == Crash ==