Fishermen found body parts, combat boots and other debris today that were believed to be from a C-130 military transport plane that crashed after taking off in the southern Philippines with nine crew members on board.
Air force chief Lt Gen Pedrito Cadungog would not speculate on the crash's cause.
Sabotage is "always a possibility," especially with the air force leading a massive air and ground assault against Muslim guerrillas, but he said the rebels were not believed to have weapons capable of bringing down a plane flying above a couple of thousand feet.
Cadungog said it is "highly probable" that the remains and debris, including a plane wheel, came from the plane, which lost contact five minutes after taking off from Davao International Airport at 8.50pm yesterday (1350 BST). The weather was clear at the time.
"It's safe to say that the aircraft crashed there, although there is a long process of investigation that has to take place," Cadungog said. "It's based on all the pieces of debris that we retrieved."
Davao police investigator Joel Parojinog said residents from a coastal village told police they recovered from shore two combat boots, human body parts, and some documents, including a C-130 manual.
He said they reported seeing a plane around 9pm Monday "going down into the sea with flames on one of the wings," followed by an underwater explosion.
Cadungog said earlier that the air force had asked for assistance from the US military, its key ally in the anti-terrorism war in the southern Philippines, and a long-range aircraft was expected to join eight other Philippine planes and helicopters later today.
Search efforts focused on a 20-mile radius around the airport, including the nearby sea, Cadungog said.
He said the C-130, with two pilots and seven other crewmen, refuelled in Davao and was headed to central Iloilo city to pick up more than 80 members of the Presidential Security Group after Monday's visit by President Gloria Macapagal Arroyo, who attended the wake of a slain army colonel.
Earlier yesterday, the plane transported combat troops from Fort Magsaysay, an army base in northern Nueva Ecija province, to Davao, a major southern airport on the edge of the coast, Cadungog said.
The central and western parts of Mindanao island have been the site of intense fighting between troops and Muslim rebels. The military has been pursuing three commanders of the Moro Islamic Liberation Front and their men who were blamed for killing dozens of civilians and pillaging communities in three southern provinces last week.
Air force helicopters and planes have been hitting rebel hide-outs "so if you read from that, you will know that if there is one force that the enemy would want to strike, it would be the air force," Cadungog said.
But he said the rebels did not have weapons that could shoot down a plane flying at more than 3,000 feet. At the time the plane lost contact, it was estimated to be flying at about 5,000 feet and climbing, he said.
Cadungog said the aircraft, built in 1971 and acquired by the air force in 1983, was last inspected on August 15, when it was fitted with a new engine. He called the C-130 a "very reliable all-weather aircraft."
Maj Donald Madarang, who flew the plane before it was turned over to another pilot for the Davao flight, said there was nothing wrong with the C-130 except for a minor instrument that helps the engine to start before takeoff. That instrument was immediately fixed, he said. The country's other C-130 was grounded for inspections.Reuse content