Investigators believe the missing Malaysia Airlines flight changed directions and altitudes a number of times before it likely crashed in the Indian Ocean, a senior U.S. official told The New York Times.
Even further, a number of a clues point to the plane's disappearance being the result of sabotage from a hijacker or crew member with intimate knowledge of aircraft systems, according to The Wall Street Journal.
On Thursday, sources speaking with ABC said they believed the data reporting system was shut down at 1:07 a.m., while the transponder — sending out location and altitude data — was shut down at 1:21 a.m. The 14-minute delay between the systems shutdown raises more questions but reveals the strong possibility the systems were purposely shut down rather than malfunctioned or failed in some sort of catastrophic accident.
As a number of commercial pilots told NPR's "All Things Considered" on Friday, with the exception of the transponder, which can be shut off at the flick of a switch, other onboard tracking systems are not as easy to disable.
"They said you'd have to go through big checklists, you'd have to possibly pull circuit breakers if you wanted to deactivate [all the communications equipment]," NPR's Geoff Brumfiel said, citing interviews with pilots. "So, to do this, you'd have to have some degree of premeditation and a lot of knowledge of the aircraft."
Such actions — to deliberately mask where the plane could be headed — point toward a possible criminal act, although investigators are not ruling out pilot error, mechanical trouble, or a catastrophic event.
"Increasingly, it seems to be heading into the criminal arena," Richard Healing, a former member of the NTSB, told WSJ. The latest findings from investigators, he continued, "indicate the emphasis is on determining if a hijacker or crew member diverted the plane."
While the investigation intensifies on a possible hijacking or actions of rogue crew that later led to a crash, the previously reported scenario that the plane could have landed somewhere for later use in a terrorist attack was considered then dismissed.
“[Radar data] leads them to believe that it either ran out of fuel or crashed right before it ran out of fuel," a senior U.S. official told the Times. "The idea it could cross into Indian airspace and not get picked up made no sense."
With in-flight tracking systems turned off, a combination of satellite tracking and military radar has left some clues for investigators to piece together what happened next.
After falling off of civilian radar, radar signals from the Malaysian military appear to show the Boeing 777 climbing above the plane's maximum ceiling to 45,000 feet before it made a sharp turn toward the west. The data then shows another turn to the southwest and descent to 23,000 feet before it finally settled on a higher altitude and bearing toward the Indian Ocean.
The latest report comes just one day after two U.S. officials revealed their belief the plane's disappearance was less likely the result of catastrophic failure and more the result of a "deliberate act."
Investigators, who widened their search area on Thursday to the Indian Ocean based on faint electronic "pings" of technical data from the flight, have now expanded into the Andaman Sea northwest of the Malay Peninsula, based on another "ping" picked up five or six times by a satellite before it was completely lost, Reuters reports.
Six days on, an unprecedented international search effort has emerged with a number of government agencies, militaries, and civilian personnel pooling resources to find the jet that went missing with 239 people on board.
"It is like finding a needle in a haystack and the area is enormous. Finding anything rapidly is going to be very difficult," Marc Pircher, director of France's Toulouse space center, told Reuters. "The area and scale of the task is such that 99 percent of what you are getting are false alarms."
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