A year to the day after Malaysia Airlines Flight MH370 vanished, not a trace of the missing jet has been found despite a multi-million dollar search operation. NBC News’ Lester Holt went aboard a Boeing 777 simulator and spoke with two aviation experts to examine several theories about what happened on March 8, 2014.
The pilots may have tried to turn around because of smoke or fire in the cabin
Despite losing contact with air traffic control, MH370 was picked up by Malaysian military radar traveling west shortly afterwards. This would have required a sharp turn to the left from the aircraft’s scheduled route from Kuala Lumpur to Beijing. Retired commercial airline pilot Rob Johnson accompanied NBC News inside the Boeing 777 simulator to look at what could have prompted this action: "Possibly something’s gone wrong in the aircraft, in the flight deck, in the cabin, and they want to turn the aircraft around and get back home." Johnson said fumes or fire could be the culprit in this potential scenario, perhaps originating from an air conditioning pack or another electrical component on board the plane.
In a bid to try to stop this emergency, the pilots may have disconnected their communications
Minutes after its last message to air traffic control — "Goodnight, Malaysian three seven zero" — the plane’s transponder, which communicates with ground radar, stopped transmitting. Johnson used the simulator to show how the pilots may have switched off this vital piece of equipment in a desperate bid to stop the potential on-board emergency. "Right now, the most immediate problem is the source of this smoke and fumes," he said, mapping out what could have happened. "I’m going to get the checklist out, I’m going to start shutting off electrics." Johnson said the pilots may have been "so engrossed in the checklist procedure — smoke, fumes — they may have disconnected" the communications. "There’s no use talking to somebody if you’re going to be dead in four or five minutes."
The aircraft may have then flown for hours while everyone on board was unconscious
Johnson said a likely course of action for pilots dealing with such an emergency would be a rapid descent to 12,000 feet, where the air is breathable and the cabin can be depressurized. If the crew were overcome with fumes, as investigators theorized in June, there would be nothing stopping the aircraft maintaining its course until its tanks were empty. “We haven't shut off the engines," Johnson said, demonstrating this course of action in the simulator. "They've got 86 metric tons of fuel, they are going to go for another six or seven hours easily." If the fuel did run out, MH370 would have "become a glider into the water," Johnson said, estimating it would have crashed 30 to 40 miles later. This fuel calculation, as well as satellite data, was what investigators used to map out the current search area.
One or both of the pilots may have steered the plane off course and crashed it deliberately
The theory that the pilots turned west because of an emergency is undermined because they did not head back toward Kuala Lumpur, according to retired NTSB senior investigator Greg Feith. The emergency scenario does not "hold true when you start to develop what would the crew do under these circumstances," Feith told said in a separate interview. Feith said that turning off the communications and taking the aircraft to the remote Indian Ocean was a course of action consistent with someone trying to purposefully lose an airliner. "It's 20,000-plus feet deep there," Feith said. "It's going be very difficult to find." He added that "the first thing you’re going to do” as a pilot during an emergency is “don the oxygen mask" and "confess to ATC [air traffic control], 'We've got an issue, we need to return.'" Feith, who investigated other so-called "murder-suicide" airline crashes while at the NTSB, said that he has “always postured at least that this was an intentional act by one or both pilots." This theory, he said, is supported by lingering questions over deleted information on the pilot's personal flight simulator.
The likely scenario is that we will never know
"There isn't really a model" for the MH370 investigation, Feith said, pointing the lack of other airliners going missing in recent aviation history. "Investigators are really hampered by the fact that we don't have a lot of data for MH370," he said. Even if search teams do find pieces of the wreckage — or the much sought black boxes — this may not be enough to solve the mystery. The cockpit voice recorder rewrites itself every two hours, so would unlikely give clues to why the plane changed course. The flight data recorder has a 25-hour memory. But Feith said it would only "tell us is what the airplane was doing. It won't tell us why."