Here’s How We Know MH370 Kept Flying for Hours

Ground staff work on a Malaysia Airlines plane at Kuala Lumpur International Airport in Sepang, Malaysia, Wednesday, March 12, 2014. (AP Photo/Lai Seng Sin)

[The Washington Post]

Ground staff work on a Malaysia Airlines plane at Kuala Lumpur International Airport in Sepang, Malaysia, Wednesday, March 12, 2014. (AP Photo/Lai Seng Sin)
Ground staff work on a Malaysia Airlines plane at Kuala Lumpur International Airport in Sepang, Malaysia, Wednesday, March 12, 2014. (AP Photo/Lai Seng Sin)

As the search for Malaysia Airlines Flight 370 continues, attention is turning to the onboard technology that allowed the plane itself, rather than the pilots, to communicate with the ground.

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. In the case of Air France 447, which plunged into the ocean off the coast of Brazil in 2009, the doomed aircraft sent 29 ACARS transmissions warning of a problem before the plane crashed.

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