The last satellite transmission from a Malaysian airliner missing for a week has been traced to the Indian Ocean off Australia, far from where searches have taken place, according to a person familiar with the analysis.
A path from Malaysia to the ocean off Australia would have taken as much as 3,000 miles, about the maximum distance the Boeing Co. 777-200 could have flown with its fuel load.
Flight 370 may have flown beyond its last known position about 1,000 miles west of Perth, and that location may not be an indication of where the plane ended up, said the person, who spoke on condition of not being named because of the sensitivity of the information.
Investigators have also found that someone in the cockpit of the Boeing Co. 777-200 programmed it to turn away from its intended path to Beijing after turning off a device identifying the jet to radar, according to another person in the U.S. government familiar with the probe.
That adds to the increasing evidence pointing to a deliberate diversion by an experienced pilot. The Malaysian Airline System Bhd. jet vanished a week ago with 239 passengers and crew members on board while flying to Beijing from Kuala Lumpur.
The plane’s last known position was fixed by analyzing pings from a transmitter that sent signals to a satellite about once an hour for 4 to 5 hours after its transponder beacon went dead and the plane changed course, the person said.
The command to change direction was captured by the Malaysian Airline System Bhd. plane’s Aircraft Communications Addressing and Reporting System, which transmits text messages and data to and from aircraft, one person said. The pilot then shut off Acars’s ability to report on the flight’s progress, the person said.
Investigators narrowed the missing Malaysian jetliner’s possible routes by mapping hours of satellite contacts that continued after Acars and other systems were shut down, according to three people familiar with the work.
The pulses provide no data about the plane’s speed, location or altitude. Still, they allow calculations of an arc along the earth’s surface where the plane was each time it communicated with the satellite. The person declined to describe the accuracy of the estimates.
Whoever was in the cockpit switched off a transponder, which sends radio beacons to radars that provide altitude and a plane’s identity as it neared Vietnamese airspace. It then made a turn to the left, flying west over Malaysia.
Unlike with the transponder, which can be shut off with a cockpit switch, disabling Acars transmissions is a more complex process, Kenneth Musser, a retired 777 pilot of Roswell, Georgia, said in an interview. It would require multiple steps, possibly requiring a pilot to consult the flight manual, Musser said.
“It’s not an accident” if it were shut off, he said.
The satellite communications came from the Acars system, according to a person in the U.S. government familiar with the equipment. Acars can communicate to ground-based stations on two different radio frequencies and via satellite while traveling over water or the poles, the person said.
Even though Acars’s ability to transmit had been blocked by someone on the Malaysian Air plane, the satellite antenna remained active and responded to radio queries from a satellite once an hour, the person said.
U.S. investigators had been studying a radar blip detected hundreds of miles west of the plane’s intended route, in the area of the Malacca Strait, about 2:15 a.m. local time March 8, about 45 minutes after the last transponder signal.
Raw radar from Malaysian military facilities appears to show the plane making abrupt altitude changes. Without a transponder to provide a plane’s altitude, radars aren’t able to provide accurate altitude data and investigators discounted the data, one of the people familiar with the case said.
The search widened yesterday even with the attempts to map the satellite contacts.
At Malaysia’s request, India’s navy started checking an area of 9,000 square kilometers (3,475 square miles) along the Chennai coast. The latest patrol area is a strip measuring 15 kilometers long by 600 miles wide, according to an Indian navy statement.
Indian surface vessels and aircraft continued to scour waters east of the Andaman and Nicobar Islands, the navy said in the statement, even as the naval official cast doubt on the possibility that Flight 370 could have reached the area undetected by radar. Malaysia said yesterday that it pushed the search farther east into the South China Sea and to the west into the Indian Ocean.
The Andaman Sea surveillance had opened a new front for investigators as signs mounted that the plane doubled back on its Kuala Lumpur-to-Beijing route and possibly flew for hours after controllers lost contact almost a week ago.
The Andaman Sea and Bay of Bengal are on the opposite side of Malaysia far from Flight 370’s intended path and from the initial search areas in the Gulf of Thailand and South China Sea. Malaysia said the hunt for the plane now involves 57 ships and 48 aircraft.