At 9:57 on the morning of May 20, 1964, the radio operator at Zamboanga Airport received a garbled, blind transmission. The voice was presumed to be the pilot of Flight F26, attempting to report the weather. When the operator called back, there was no answer. Three minutes later, a De Havilland Canada DHC-3 Otter struck a hillside at Sibuco Point, approximately 200 feet above sea level, in heavy rain with near-zero visibility. The aircraft hit a molave tree in a left bank, severing the left wing. The nose section struck another tree before the wreckage settled at a 30-degree angle. Fire consumed what remained. There were no survivors.
The DHC-3 Otter was built for exactly the kind of flying the Philippines demanded: short runways, rough strips, remote communities. Philippine Air Lines operated six of them as part of their Rural Air Service, connecting towns that had no other reliable transportation link. The aircraft that flew Flight F26 -- construction number 68 -- was the first Otter delivered to the airline, acquired in February 1955. It had been test-flown at Downsview in Toronto, then disassembled, shipped to Manila, and reassembled for Philippine service. By the morning of the crash, it had accumulated 7,197 flight hours and was properly maintained according to its manual, with an airworthiness certificate valid until August of that year.
Flight F26 departed Zamboanga Airport at 6:50 AM on a route that would take it to Siocon, then Liloy, then Dipolog, before returning through Siocon and back to Zamboanga. The Otter landed at Siocon at 7:30, where the pilot -- a 32-year-old captain with 4,163 hours of flight time, including 342 on the DHC-3 -- learned that weather conditions ahead and at his destination were unfavorable. He decided to skip the rest of the route and return directly to Zamboanga. Heavy rain and squalls had settled over the western Mindanao coast, conditions that were emphatically unsuitable for visual flight. The DHC-3 Otter carried no navigational aids. It could only fly under visual flight rules.
The pilot took off from Siocon and flew southward along the jagged coastline toward Zamboanga. The weather was worse than unfavorable -- it was, by the investigation's assessment, practically zero visibility due to heavy rain. A squall sat directly over Sibuco Point. The aircraft had no instrument landing capability, no automatic direction finder, and no way to navigate except by looking out the windshield at terrain that had disappeared behind a wall of water. At approximately 10:00 AM, the Otter struck the hillside. The wreckage was found hours later. It was the fourth PAL DHC-3 Otter to crash.
The Civil Aviation Administration acted quickly. PAL's remaining Otters were grounded until they could be fitted with automatic direction finders and more powerful high-frequency radios, and the airline was ordered to exercise greater supervision over its pilots based at Zamboanga. But the Otters never returned to regular service. The two surviving aircraft in PAL's fleet were eventually used only for charter flights before being sold. The Rural Air Service that had connected Mindanao's small communities lost its workhorses. The crash at Sibuco Point did not just end eleven lives -- it ended an era of bush flying in the Philippine archipelago.
The crash site at Sibuco Point is at approximately 7.251N, 122.017E on the western Mindanao coast between Siocon and Zamboanga City. The terrain is hilly and rises steeply from irregular, jagged shorelines -- the impact occurred at about 200 ft ASL. Zamboanga International Airport (RPMZ) is approximately 40 km to the south. The route from Siocon to Zamboanga follows the coast, with hills rising sharply from the shore. Pilots should note that this corridor remains prone to sudden heavy rain and squalls, particularly during monsoon season. The lesson of Flight F26 -- that VFR flight along this coast in poor visibility is lethal -- remains relevant.