The disappearance of Flight MH370 could have only involved human input, according to a veteran Boeing 777 check captain.
Speaking exclusively to _The West Australian _the check captain said that given the facts we know, for MH370 to end its flight in the southern Indian Ocean, "human input was essential".
"We are not dealing with an out of control plane," he said.
"It is impossible for the Boeing 777 to fly this course by itself."
MH370 made three course changes and at least two altitude changes, according to the Malaysian military.
"To change course requires the pilot to either disengage the flight management computer and dial in a new heading to the autopilot/flight director or fly manually," the check captain said.
The jet then apparently increased its altitude to 45,000ft (13,716m), according to returns to Malaysian military radar, before descending as low as 5000ft (1524m).
"This would have required input to reselect altitude in the autopilot/flight director or manually to fly the plane and typically reduce engine thrust," the check captain said.
MH370 then made two more turns - the first to the north-west and then due south.
According to the check captain, the 777 would have had to climb back to its cruising altitude of 35,000ft (10,668m) because it would never have reached the southern Indian Ocean with the fuel load it had.
"At say 12,000ft (3657m) it burns eight tons of fuel an hour but we can only fly at a top speed of 340 knots (629km/h)," the check captain said.
"But at 35,000ft we would burn seven tons of fuel an hour and fly at 480 knots (890km/h)." If MH370 had stayed at 12,000ft it would have reached only Carnarvon.
The check captain's revelations of human input come as the captain of MH370, Zaharie Ahmad Shah, comes under renewed scrutiny.
According to a New Zealand Herald report, Capt. Shah's wife had just told him she was leaving their marriage.
A friend of Capt. Shah said he "was in no state to fly".
When MH370 ran out of fuel and if nobody was in control, the Boeing 777 would not have glided down slowly, according to the check captain.
"With no engine power and no one flying it would have gone into a spiral and straight down possibly reaching supersonic speeds," he said.
"Parts would have started to break off like ailerons and trim tabs."
However, within one minute of the engines quitting, the plane's auxiliary power unit located in the tail, with its own fuel supply, would have started automatically and brought power back to the electrical systems.
This may account for the final partial ping from the plane picked up by Inmarsat at 8.19am.
No response was received from the plane at 9.15am, when the ground earth station sent the next log on/log off message or ping.
This indicates that the plane was no longer logged on to the network and is consistent with the limit of its range with its fuel load.
Yesterday, the search continued with 11 planes.
More items were spotted but not relocated on second passes.
'It is impossible for the Boeing 777 to fly this course by itself.' " Boeing 777 check captain