The international search for the missing Malaysian jetliner expanded further into the Indian Ocean on Friday amid signs the aircraft may have flown on for hours after its last contact with air-traffic control nearly a week ago.
A U.S. official told The Associated Press that the Malaysia Airlines plane sent signals to a satellite for four hours after the aircraft went missing early last Saturday, raising the possibility the jet carrying 239 people could have flown far from the current search areas. It also increased speculation that whatever happened to the plane was a deliberate act.
Malaysia's Transport Minister Hishammuddin Hussein said the search was expanding further afield, not because of any new information about the plane's flight, but because the aircraft has not yet been found.
Malaysian officials declined to discuss when —or even whether — they had information about signals to satellites, and that they would release details only when verified. Hishammuddin said Malaysian investigators have worked with U.S. colleagues in Kuala Lumpur since Sunday.
"I hope within a couple of days to have something conclusive," he told a press conference.
If the plane had disintegrated during flight or had suffered some other catastrophic failure, all signals — the pings to the satellite, the data messages and the transponder — would be expected to stop at the same time. Experts say a pilot or passengers with technical expertise may have switched off the transponder in the hope of flying undetected.
No theory, however, has been ruled out in one of aviation history's most puzzling mysteries.
The Beijing-bound Boeing 777-200 last communicated with air traffic base stations east of Malaysia in the South China Sea, which for several days has the main focus of the search. Planes and ships also have been searching the Strait of Malacca west of Malaysia because of a blip on military radar suggested the plane might have turned in that direction after the last confirmed contact.
Mike Glynn, a committee member of the Australian and International Pilots Association, said he considers pilot suicide to be the most likely explanation for the disappearance, as was suspected in a SilkAir crash during a flight from Singapore to Jakarta in 1997 and an EgyptAir flight from Los Angeles to Cairo in 1999.
"A pilot rather than a hijacker is more likely to be able to switch off the communications equipment," Glynn said. "The last thing that I, as a pilot, want is suspicion to fall on the crew, but it's happened twice before."
Glynn said a pilot may have sought to fly the plane into the Indian Ocean to reduce the chances of recovering data recorders, and to conceal the cause of the disaster.
Experts said that if the plane crashed into the ocean, some debris should be floating even if most of the jet is submerged. Past experience shows that finding the wreckage can take weeks or even longer, especially if the location of the plane is in doubt.
Lowy reported from Washington. Associated Press writers Ashok Sharma in New Delhi, Jim Gomez in Kuala Lumpur, Tran V. Minh in Hanoi, Vietnam, Thanyarat Doksone in Bangkok, Rod McGuirk in Canberra, Australia, and Josh Lederman in Washington contributed to this report.