A section of wing from missing Malaysia Airlines flight MH370 shows evidence it was extended upon landing, suggesting a rogue pilot brought it down, an air crash expert says.

World expert air crash investigator Larry Vance believes no other theory can explain the fate of the doomed aircraft.

“Somebody was flying the airplane into the water,” he told Channel Nine’s 60 Minutes program on Sunday.

The Australian search has been based on the theory the jet was not under human control when it crashed with 239 people on board, en route from Kuala Lumpur to Beijing on 8 March 2014, after it inexplicably veered off course and headed south over the Indian Ocean.

Vance believes a small section of wing, called the flaperon, found a year ago off the coast of Madagascar, shows “definite evidence” it was extended at the time of landing – and the extending can only be activated by a person.

The failure to find floating debris could also be explained by a slow, controlled landing, he said.

Australian Transport Safety Bureau crash investigator Peter Foley agreed the crash could have been the work of a rogue pilot. He said analysis from French authorities showed it was possible the plane was in a “deployed state”.

The flaperon is in the hands of the French, and Malaysian investigators have been unable to take possession of it, a year after its discovery.

“I think it’s been a frustration for the investigation,” Foley said.

He conceded that if the plane was piloted until the end, it could have landed outside the current search area: “There is a possibility there was someone in control at the end and we’re actively looking for evidence to support that.”

It was recently revealed the captain’s home flight simulator showed a month before the doomed flight, he plotted an almost identical route deep into the southern Indian Ocean.

Foley said the reason it hasn’t been included in an interim report on the investigation was a “question for the Malaysians”, but it should form part of a final report.

Another piece of evidence, a wing part recently found in Tanzania, was being analysed to determine if it was extended at the end of the flight.

If it was extended, it meant someone was in charge of the aircraft,Foley said.

However, Vance said the discovery of the flaperon, which showed damage consistent with the force of water, should have prompted experts to conclude the crash was caused by a rogue pilot.

“Everybody should then have concluded in my opinion that this was a human engineered event, there’s no other explanation,” he said.