Passengers on flight MH370 died of oxygen starvation hours before the pilot performed a controlled ditching in the Indian Ocean, according to a new study into the disaster.
Analysis by a veteran air accident investigator suggests that all 239 people lost consciousness up to four hours before the Boeing 777 disappeared beneath the waves.
The most likely scenario is that pilot Zaharie Ahmad Shah deliberately depressurised the cabin, thereby depriving those on board of air, the research concludes.
Although oxygen masks would have dropped down automatically from above the seats, their supply was limited to just 20 minutes.
Those unable to grab a mask, including sleeping passengers, would have passed out within the space of a few minutes.
The entire ‘ghost plane’, including her cabin crew whose air supply is only marginally longer, would have slipped into a coma and died shortly after from oxygen starvation.
Ahmad Shah, who locked his co-pilot out of the cockpit, survived long enough – either by re-pressurising the aircraft, or from breathing his own, more extensive air supply – to evade radar and “execute his master plan”, researchers have concluded.
He then performed a controlled ditching in the sea, which would explain why no debris has been found because the plane landed and sank in one piece.
The theory is the result of the first independent study into March’s disaster by the New Zealand-based air accident investigator, Ewan Wilson.
Wilson, the founder of Kiwi Airlines and a commercial pilot himself, arrived at the shocking conclusion after considering “every conceivable alternative scenario”.
An earlier report from the Australian Transport Safety Bureau (ATSB) also concluded that passengers may have died from hypoxia. And Malaysian authorities previously named Ahmad Shah as their prime suspect.
But the ATSB report contained no new evidence from within the aircraft and, until now, the pilot’s premeditated actions – and the disturbing scenario that played out in the cabin – have never before come to light.
The remarkable claims are made in the book ‘Goodnight Malaysian 370’, the culmination of a four-month study into the incident, which Wilson co-wrote with the New Zealand broadsheet journalist, Geoff Taylor.
Wilson, a qualified transport safety investigator, said: “One of our objectives in writing this book was, in some small way, to convey the human stories of the tragedy. Our other, more important task was to pursue the truth about what really happened; that is one small contribution we felt we could make to this whole, terrible affair.
“We could never have foreseen the information we uncovered, or their implications. Neither could we have imagined the horrific scenario that our research suggests took place on board that fateful plane.”
Wilson and Taylor’s entire scenario makes for difficult reading. They believe that Ahmad Shah, who they have concluded was suffering from mental illness, tricked his co-pilot Fariq Hamid into taking a break about 40 minutes after take-off.
After locking Hamid out of the cockpit, Ahmad Shah made his last broadcast to air traffic control – “Goodnight, Malaysian 370” – before switching off the aircraft’s air-to-ground communication links.
Alone at the controls, he took MH370 up to 39,000 feet and depressurised the aircraft, giving passengers crew less than 60 seconds of Time of Useful Consciousness (TUC) time.
While Ahmad Shah could not have prevented the plane’s oxygen masks from automatically dropping down, or an automated emergency announcement in English.
But Flight 370 was a night flight and, with the cabin lights off, the majority of passengers would have been asleep, or close to it. For 227 of the 239 passengers, English was not their first language.
Cabin crew would have tried to help those on board, but would have had to have donned their own facemasks first.
“It would have been a frightening and confusing time throughout the cabin,” Taylor said. “By the time some of the passengers had woken up groggy, heard the commotion and looked around in confusion, it would have been too late for them.
“Those passengers who did not react within 60 seconds or less would have lapsed into unconsciousness and death would have followed within four to six minutes.”
Those who had found a mask would have had between 12 and 22 minutes of breathing time before blacking out.
The cabin crew’s oxygen supply would have lasted for about 70 minutes, depending upon the height of the aircraft.
By the time MH370 returned to cruising altitude, everyone on board would have perished.
Ahmad Shah would have had three hours’ worth of oxygen – plenty enough, the authors believe, to carry out the “final act of his performance”.
They conclude that he set a course for the southern Indian Ocean and, after the fuel ran dry, glided the aircraft for a further 100 nautical miles before performing a controlled ditching on the surface of the water.
Wilson, a trained commercial pilot, said: “Ahmad Shah was a man known for his methodical, thorough nature, for his love of the technical, and probably for his ego, too.
“This would have been his final sad act to his family and to the world: ‘find this one’.”