Given ideal weather conditions and the modern aircraft they were flying, pilot Zaharie Ahmad Shah and first officer Fariq Ab Hamid probably had the autopilot engaged when Flight 370 disappeared from view, Hong Kong aviation experts said yesterday.
At the time contact was lost, the Beijing-bound Boeing 777 would have been at the cruise stage of its flight from Kuala Lumpur, they said. Two hours after take-off, the plane was moving at mach 0.84, or 1,000km/h, and flying at an altitude of 11,000 metres during what is considered the safest stage of the journey.
"It should be the easiest part of the flight," said Dai Evans, flight operations manager for the Hong Kong Government Flying Service.
"When you're in the cruise mode, you've hardly got anything to do. The most would be to change where you are going, either left or right."
A senior executive with a major Hong Kong-based airline said that at the two-hour mark in the journey, the plane would almost certainly have been in autopilot.
"It is bizarre. I would have no idea [why there would be a problem that means a plane disappears]," he said.
"There would be many things that would cause the autopilot to not work, but it would have to be multiple failures."
Evans, who has worked in search and rescue for 27 years with experience in Britain, Cyprus and the Falkland Islands, said that the most dangerous times of a flight are during take-off and landing.
"That's because it is operating closer to the aircraft limits and flying at the stalling speed," he said, referring to a slower speed that pilots must fly at when preparing to land or take off.
"But when you are cruising on autopilot, you're not flying close to the ground and not changing speed or height."
Another pilot with more than 30 years' experience said the cruising time was "very low risk".
"In cruise, it's quite relaxed," he said.
"At 35,000 feet [11,000 metres], there's no terrain issue and there are less things happening. You're not descending or ascending."
During take-off and landing, the procedures are "quite intensive" and there are strict limitations on the pilots.