Malaysian Airlines Flight 370's transponder and communications were deliberately turned off before it reached the east coast of the Malaysian Peninsula. Mikael Robertsson, co-founder of the flight-tracking website FlightRadar24, tells us how the plane could continue to fly under the radar.
KUALA LUMPUR, Malaysia—Malaysia's prime minister said he believes that "deliberate action" caused the disappearance of Malaysia Airlines 3786.KU +2.13% Flight 370, and authorities are now focusing on two areas in the search for the plane.
In the first definitive comments from the nation's government on how the jet came to vanish March 8, Najib Razak said at a news conference Saturday that data relayed by the plane to a satellite has confirmed it turned from its original course. He added that the last satellite communication from the plane was at 8:11 a.m. Malaysia time, well past the scheduled arrival time in Beijing. It had taken off from Kuala Lumpur International Airport at 12:41 a.m.
Malaysia's leader says communications systems on Flight 370 were cut off by "deliberate action." U.S. officials are investigating whether a third system, on the plane's lower deck, was also compromised. WSJ's Jason Bellini explains. Image: AP
The prime minister's comments appear to corroborate the analysis of U.S. investigators, which determined that one or more people on the plane deliberately changed its course and tried to mask its location.
The routine messages sent by the aircraft show that Flight 370 was still airborne nearly six hours after it disappeared from Malaysian military radar. The BoeingBA +1.00% 777-200 plane with 239 people on board was carrying enough fuel to fly for eight hours, Malaysia Airlines confirmed on Saturday.
Mr. Najib said that while hijacking has been raised as a possibility, "we are still investigating all possibilities as to what caused MH370 to deviate from its original flight path."
Based on the new data, aviation authorities of Malaysia and counterparts in other countries have determined that the plane's last satellite communication came from one of two corridors, Mr. Najib said: a northern one stretching approximately from the Kazakhstan-Turkmenistan border to northern Thailand or a southern one stretching approximately from Indonesia to the southern Indian Ocean.
If Flight 370 traveled north, it might have been above Thailand, China, Myanmar, Kazakhstan, Uzbekistan or Turkmenistan at 8.11 a.m., according to the satellite data released by Kuala Lumpur. However, it would have needed to fly through the airspace of several countries to have reached that point, and it is unlikely that it could have done so undetected, especially if it passed close to China or India, both of which have air-defense systems.
The automated message would have revealed the plane's distance from the satellite at 8.11 a.m., but not its precise location, said Mikael Robertsson, co-founder of Flightradar24, a website that uses satellite data to track commercial flights.
Authorities have "refocused" attention onto the crew and passengers, said Mr. Najib. While he said there is a "high degree of certainty" that the plane's two communications systems were disabled, it remains unclear who might have taken that step and whether he or she was acting with others on the flight.
Physically disconnecting communications systems would require detailed knowledge of the aircraft's internal structure and systems, aviation officials said. But a possible motive for such a disconnection remains unclear. Malaysia Airlines confirmed Saturday that Flight 370 wasn't carrying any valuable cargo.
Mr. Najib didn't take questions from the reporters who packed the airport-hotel function room where he spoke.
Search teams have been withdrawn from the South China Sea, the area from which the plane's transponder, which relays identification signals to ground radar, sent its last signal. "Clearly, the search for MH370 has entered a new phase," he said.
As of Saturday, 43 ships and 58 aircraft from 14 countries are involved in the search, the prime minister said.
The latest revelations indicate that the search areas will be significantly expanded, while Vietnam announced it would cease search operations following the prime minister's statement.
On Saturday, the U.S. Navy's Seventh Fleet confirmed that it had spent the day searching the Bay of Bengal far to the northwest of Malaysia. However, it now appears unlikely that Flight 370 could have flown there, given the bay's distance from both corridors highlighted by the prime minister.
A spokesman for the Seventh Fleet said patrol schedules were planned only one day in advance and the U.S. Navy "will not fly to the south" of the Bay of Bengal on Sunday, despite Mr. Najib's statement.
Malaysian Prime Minister Najib Razak says investigators are looking at profiles of passengers and crew on Flight 370. The WSJ's Jeffrey Ng tells us where the investigation is headed next.
China's Ministry of Foreign Affairs said the country will adjust its search efforts based on the prime minister's statement, but that it was seeking more detailed information from Malaysia.
Beijing, which has deployed eight sea vessels, two aircraft and five helicopters to search in the South China Sea, has repeatedly pressed Malaysia to redouble its efforts, as Chinese officials have come under criticism for inaction from the passengers' family members. "Time is life," the ministry said.
Some of the families of Flight 370 passengers said following the prime minister's remarks that there is hope their loved ones are alive.
A friend of Norli Akmar Hamid of Kuala Lumpur, who was headed to Beijing on her honeymoon, said, "At least we know that she was alive up to 8:11 a.m. on March 8." The friend, who asked not to be identified, added, "Previously, I thought the plane crashed when it was lost from the radar. There is still hope."
A father of a Malaysian aircraft engineer on Flight 370 said he is hopeful, too. "The chances of finding the aircraft was brighter. The situation is clearer," said Selamat Omar, the father of 29-year-old Mohamad Khairul Amri.
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Selamat Omar, father of 29-year-old Mohamad Khairul Amri, who was on Flight 370, said he is hopeful. Jake Watts Maxwell/The Wall Street Journal
Based on new satellite information, investigators suspect the plane's Aircraft Communications Addressing and Reporting System, or Acars, was disabled just before the aircraft reached the east coast of Malaysia. Shortly afterward, near the border between Malaysian and Vietnamese air traffic control, the transponder was switched off.
The plane then flew west back over Malaysia before turning northwest, Mr. Najib said, citing Royal Malaysian Air Force radar data, now confirmed by the National Transportation Safety Board and the Federal Aviation Administration of the U.S., and the Air Accidents Investigation Branch of the U.K.
To refine the search, investigators are now calculating how far the aircraft could have flown after this last point of contact.
"As the two new corridors involve many countries, the relevant foreign embassies have been invited to a briefing on the new information today by the Malaysian Foreign Ministry and the technical experts," the prime minister said.
Malaysia Airlines has been informing the families of the passengers and crew of the new developments.
Mr. Robertsson, of Flightradar24, said a crash on land rather than into the sea was unlikely because the aircraft's emergency beacon would have automatically flashed its location via satellite or radio. The beacon's signals are less easy to find if an aircraft crashes into the sea.
—Celine Fernandez and Trefor Moss in Kuala Lumpur and Laurie Burkitt in Beijing contributed to this article.