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Here’s how we know MH370 kept flying for hours

Here's how we know MH370 kept flying for hours

Even if an aircraft's transponder has been disabled, its most basic systems, such as the engines, can also send status information back to ground stations, including the engine manufacturer  or the airline. Investigators have now determined that some of these systems were still active on Flight 370 hours after it initially lost contact with air traffic controllers. The question is whether this low-level data is enough to provide new insight on where the plane may have gone.

What is this technology, and how does it work?

Investigators are focusing on data relayed by a system called ACARS, or Aircraft Communications Addressing and Reporting System. In basic versions of the service, the airplane shares data automatically in short radio bursts with airline officials. ACARS allows the plane to send multiple types of messages, including information about fuel levels and engine status.

You mentioned basic implementations. There's more than one ACARS?

Think of it like a cable TV package. According to Bill Waldock, an air crash investigator and a professor at Embry-Riddle Aeronautical University, more expensive ACARS packages come with a console that can receive short faxes  or send basic messages. Depending on what an airline is willing to pay for, its planes will be able to take advantage of more and better ACARS features.

Okay. So can this technology tell us where Flight 370 is?

Not necessarily — it can really only tell us whether the plane is still functioning.

"Normally, ACARS doesn’t send an actual location," Waldock said. "They're sending essentially system data. They don't indicate altitude or direction. But as long as it’s pinging, you know the airplane is not down."

Investigators now say that based on ACARS information, Flight 370 deviated from its flight path and was in the air for hours after it ceased communications with air traffic controllers.

"The facts are all over the place," said a U.S. official who asked not to be identified because he is not authorized to speak publicly. "It's looking less and less like an accident. It's looking more like a criminal event."

Meanwhile, a satellite operator offered a glimmer of hope Friday when it confirmed it had received "ping" signals from MH370. The company, Inmarsat, said it might be able to use the angle of the incoming transmissions to calculate MH 370's position relative to the satellite. (Here is the news release from the company.)

Could passenger cellphones hold a clue?

Maybe. But it would depend on a) whether MH370 crossed back over land; b) whether there were cell towers nearby; c) whether the plane was moving low and slow enough to pick up the signals; and d) whether the towers were capable of handing off the devices from one to another well enough to establish a geographic fix as the passengers zipped by at high speeds.

"It's certainly possible under 10,000 feet," said Daniel Berninger, a communications architect and former Bell Labs employee. "But at 35,000 feet, going at 500 mph? I'm not aware of any signals being able to connect. ... The coverage between the cell towers and the handoffs is a whole complex process that doesn't always work. It doesn't even work that great when you're going 55 miles per hour in a car."

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Missing Airliner May Have Reached Central Asia. Could the Passengers Still Be Alive?

Not likely, but possible, it would be the best news ;)

Posted by some pilot friends supporting the theory that the plane shadowed another jet heading West:

"After looking at all the details, it is my opinion that MH370 snuck out of the Bay of Bengal using SIA68 as the perfect cover.  It entered radar coverage already in the radar shadow of the other 777, stayed there throughout coverage, and then exited SIA68’s shadow and then most likely landed in one of several land locations north of India and Afghanistan."


Well documented thread circulating among avionics buffs on Facebook.

Interesting theory.  I wonder if we will ever know?

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