Missing Malaysian plane mystery deepens as new timeline revealed

Malaysian officials said earlier that those words came after one of the jetliner's data communications systems — the Aircraft Communications Addressing and Reporting System — had been switched off, suggesting the voice from the cockpit may have been trying to deceive ground controllers.

However, Ahmad said that while the last data transmission from ACARS — which gives plane performance and maintenance information — came before that, it was still unclear at what point the system was switched off, making any implications of the timing murkier.

The new information opened the possibility that both ACARS and the plane's transponders, which make the plane visible to civilian air traffic controllers, were turned off at about the same time. It also suggests that the message delivered from the cockpit could have preceded any of the severed communications.

Turning off a transponder is easy and, in rare instances, there may be good reason to do so in flight — for example, if it were reporting incorrect data.

The Malaysian plane does not appear to fit that scenario, said John Gadzinski, a 737 captain.

"There is a raised eyebrow, like Spock on Star Trek — you just sit there and go, 'Why would anybody do that?"' Gadzinski said of what he is hearing among pilots.

Other pilots in the United States cautioned against reading too much into what little is known so far about the actions of the Malaysia Airlines crew.

"You can't take anything off the table until everything is on the table, and we don't even have an aircraft," said Boeing 737 pilot Mike Karn, president of the Coalition of Airline Pilots Associations.