The data stream that was interrupted shortly after 1 a.m. on March 8 flows through a two-way onboard computer system known as ACARS, the Aircraft Communications Addressing and Reporting System.
“It is very possible for you as a pilot in the cockpit to turn off the ACARS system,” the official said. “If you knew what you were doing in the cockpit, you could shut off ACARS transmission.”
But the ability of the satellite to locate the plane — which he referred to as a “handshake” in which no information is exchanged — cannot be terminated from the cockpit.
“There’s no push button,” he said. “There’s no circuit breaker that would allow you to shut off the handshake.”
That satellite handshake took place on a system operated by Inmarsat, a British satellite company that provides global mobile telecommunications services.
U.S. officials declined to say how closely that handshake allowed them to track the path of the missing plane.