Flight MH370 which went missing a decade ago took on extra fuel and oxygen before take-off, leaked documents have revealed.
The flight with 239 passengers heading for Beijing disappeared from flight radar over the South China Sea and has never been found.
A leading theory is that Captain Zaharie Ahmad Shah may have crashed the plane on purpose, thereby killing himself and those on board.
British Boeing 777 pilot Simon Hardy believes flight documents showing extra oxygen and fuel being put onto the plane could be a key clue.
He told The Sun how the addition could add weight to the theory that the plane's disappearance was premeditated.
He said oxygen levels would have been sufficient enough for a short flight to Beijing and didn't meet the official requirements to be topped up.
But a scribbled note on the log reveals that the oxygen solely for the cockpit was topped up as a last-minute request but not for the cabin crew or the passengers.
The extra fuel would have given the pilot an extra half hour flying time which would have allowed the plane to make it past dawn and into daylight when a premeditated ditching would be easier.
Mr Hardy told the Sun: "It's an incredible coincidence that just before this aircraft disappears forever, one of the last things that was done as the engineer says nil noted[no oxygen added], then someone else gets on onboard and says it's a bit low.
"Well it's not really low at all… it's a strange coincidence that the last engineering task that was done before it headed off to oblivion was topping up crew oxygen which is only for the cockpit, not for the cabin crew."
He said the extra oxygen would mean the plane's pilot could have have been in control the whole time until he ditched. He calculates that the likely zone the flight ditched was in the South Indian Ocean in an area yet to be searched.
A possible resting pace could have been the Geelvinck Fracture Zone, he told the Sun.
The trench is hundreds of miles long and prone to earthquakes which could mean the plane is under rocks.
On the extra fuel on board he said: "If you want to do a good ditching, you do it in daylight or at least half daylight.
"In the case of MH370, if the pilot has another half an hour of fuel it will be daylight.
"Another half an hour of flying would be another 244 nautical miles and the most important thing is that it will be dawn."
