Authorities have been combing an area roughly the size of Greece for two years

Authorities leading the underwater hunt for the missing Malaysia Airlines jet MH370 say they believe the plane may have glided down rather than dived in the final moments, meaning they have been scouring the wrong patch of ocean for two years.

Flight MH370 searchers led by engineering group Fugro have been combing an area roughly the size of Greece for two years.

The search, spread over 120,000 square kilometres of the southern Indian Ocean off Western Australia, is expected to end in three months and could be called off after that following a meeting of Malaysia, China and Australia on Friday.

“If it's not there, it means it's somewhere else,” Fugro project director Paul Kennedy told Reuters.

“If it was manned it could glide for a long way,” Mr. Kennedy said. “You could glide it for further than our search area is, so I believe the logical conclusion will be well maybe that is the other scenario.”

The latest development is expected to fuel calls for all data to be made publicly available so that academics and rival companies can pursue an "open source” solution — a collaborative public answer to the airline industry's greatest mystery.

The glide view is not supported by the investigating agencies: America's Boeing Co, France's Thales SA , U.S. investigator the National Transportation Safety Board, British satellite company Inmarsat PLC, the U.K. Air Accidents Investigation Branch and the Australian Defence Science and Technology Organisation.

But Mr. Kennedy said a skilled pilot could glide the plane approximately 120 miles (193 km) from its cruising altitude after running out of fuel. One pilot told Reuters it would be slightly less than that.

For the aircraft to continue gliding after fuel has run out, someone must manually put the aircraft into a glide - nose down with controlled speed.

“If you lose all power, the auto-pilot kicks out. If there is nobody at the controls, the aircraft will plummet down,” said a captain with experience flying Boeing 777s — the same as MH370. Like all pilots interviewed for this story, he declined to be named given the controversy around the lost jet.