A Royal New Zealand Air Force aircraft searching for missing MH 370
IN PHOTO: The shadow of a Royal New Zealand Air Force (RNZAF) P3 Orion maritime search aircraft can be seen on low-level clouds as it flies over the southern Indian Ocean looking for missing Malaysian Airlines flight MH370 March 31, 2014. Reuters/Stringer

The missing flight MH370 was set on autopilot before it continues traversing the path towards Southern Indian Ocean, Deputy Prime Minister Warren Truss told press Thursday.

Truss said that it was "highly, highly likely that the aircraft was on autopilot" before it crashed.

"Otherwise it could not have followed the orderly path that has been identified through the satellite sightings," he explained.

Commissioner of the Australian Transport Safety Bureau (ATSB) Martin Dolan agreed.

"Certainly for its path across the Indian Ocean we are confident that the aircraft was operating on autopilot until it went out of fuel," Dolan said.

"The basic assumption would be that if the autopilot is operational it's because it's been switched on," Dolan said when asked whether the autopilot would have to be manually switched on or it could have been automatically activated.

However, why the need for autopilot and when autopilot was switched on remained unknown to the authorities.

"We couldn't accurately, nor have we attempted to, fix the moment when it was put on autopilot. It will be a matter for the Malaysian-based investigation to look at precisely when it may have been put on autopilot," Warren said.

For University of new South Wales aviation expert Peter Marosszéky, if investigation could establish that the autopilot was still working up until the crash, then there was also a deliberate act to switch off the aircraft's communications system. Hence, the plane did not suffer any major malfunction or catastrophe.

"It would appear very unlikely that power was removed from most of the essential systems, because you can't connect your autopilot if your flight management computers aren't operating. It would appear that it lost all communication and identification with air traffic control because those systems were turned off. You can't connect the autopilot if you've got systems that have been put out of action," Marosszéky told the Associated press.

For John Cox, a Washington, D.C.- based aviation consultant, former airline pilot and accident investigator, the autopilot might have been switched on by someone with profound expertise.

"Someone with knowledge interacted with the flight management computer and told it to do certain things which requires knowledge of the proper entry key strokes to get it entered and to have the computer exercise those instructions," Cox told AP.

The theory of MH370 flying on autopilot had been circulating as early as two weeks after the flight went missing but this was the first time that authorities nod on it.

On March 18, Captain Mark Nebbia of American Airlines with over 20,000 hours in the cockpit and flown planes since 1986, explained that MH370 will not just wander off course "unless the autopilot got kicked off".

"In that case, the airplane comes off autopilot and goes into a heading hold, and that essentially means that the aircraft will stay on whatever heading it had at the time that the computer kicked it off. However, I would say that the likelihood of an autopilot getting kicked off is very rare. I've seen aircraft go into heading hold mode close to an airport, but I've never seen it happen on a long-range route, like Malaysia Airlines Flight 370," Nebbia told the Popular Mechanics.

Nebbia explained that "if the airplane is in level flight, autopilot is engaged, the navigation system is hooked up to the flight plan and no changes were entered into the computer navigation system, it would stay on track".

"If the airplane is on autopilot, it thinks that it needs to fly a certain heading, so it's going to try to stay on course the whole time as its fuel runs out and its airspeed bleeds off. Once that happens, the airplane stalls, the autopilot turns off and the airplane is lost," Nebbia pointed out.

Independent of MH370, one expert had said that for a plane to fly on autopilot, someone must be responsible.

Patrick Smith, a veteran airline pilot and author of the book Cockpit Confidential, explained what it means when a plane is being flown on autopilot.

Smith was interviewed regarding the Asiana Airlines, also a Boeing 777 aircraft, that crash-landed from Seoul into to the runway at San Francisco's airport in July of 2013.

Smith says that to say a plane is flying on autopilot, it will be better to use the term "auto flight system".

"'Auto flight system' is preferred "because we're actually talking about a collection of subsystems that help control various aspects of a flight: heading, altitude, course, speed, engine power, etc. Different components are used at different times, and can be used together or separately, depending," Smith told the National Geographic.

"There is a thing called the autopilot, which frees you from having your hands physically on the controls. There's also something called the autothrottle, which controls engine thrust. I say 'controls', but it's doing so in response to what's needed and input by the crew," Smith explained further.

According to Smith, the biggest misconception about autopilot is the notion that pilots just sit there while the plane flies itself from City A to City B.

"It's infuriating to know that people believe this, because it's utterly false. Airplanes do not fly themselves. The crew flies the airplane through the automation. A plane cannot fly itself any more than an operating room, with all of its advanced technical equipment, is able to perform an organ transplant by itself. The equipment makes things easier, but the operation itself is controlled by humans," Smith expounds.

Smith highlighted that controlling the plane using automated systems "hands off" is only performed in extreme low-visibility conditions, and the airplane, pilot, and airport all have to be certified.