In an opinion piece published in The Australian, Mike Keane, a senior commercial airline and fighter pilot, said the investigation into the matter seemed to clear the MH370 pilots from suspicion by suggesting third-party involvement instead.

“The Malaysian investigation, to my mind, has failed on all of these criteria (to make the report credible) and has not provided justice to the victims and families.

“The one factor that has not been adequately addressed in the main report of 450 pages and another 1,000 pages of appendices is pilot involvement,” Keane said.

He said he believed the MH370 tragedy was not an accident but the deliberate destruction of the aircraft, resulting in the deaths of 239 innocent victims.

MH370 vanished on March 8, 2014, en route to Beijing from Kuala Lumpur.

Investigators have never been able to explain why the jet abandoned its route shortly into the flight, traversed Malaysia and then cruised south over the Indian Ocean.

The MH370 investigation team recently said that they were unable to determine why the flight, considered to be the greatest aviation mystery in history, had diverted from its original route.

It said it was difficult to attribute the aircraft’s change in course to any specific system failure, adding system manipulation was more likely.

“The possibility of intervention by a third party cannot be excluded,” said Kok Soo Chon, chief inspector the MH370 investigation team.

But Keane was adamant that pilot hijack by the captain was the “only realistic scenario that fits with the known facts.”

“(This) raises the question as to how a third party could have gained access to the cockpit, disabled the aircraft’s electronic equipment, “neutralised” the two pilots, then seated themselves before flying the aircraft through a demanding manoeuvre in the space of two minutes.

“It beggars belief. Besides, access could be gained only through a locked cockpit door that is also monitored by a flight deck entry video system from the cockpit,” he explained.

Captain Zaharie Ahmad Shah was the pilot in command. His first officer was Fariq Abdul Hamid.

Keane also claimed Zaharie had made a “lazy turn” and routed the aircraft to Penang, where he was born and went to school.

“The 10 nautical miles displacement to the south of the island would have provided him with a good view from the left seat of the aircraft.

“This could be interpreted as a last, emotional farewell,” he said.

He also claimed Zaharie was upset about PKR president Anwar Ibrahim’s 2012 sodomy conviction.

Anwar was sentenced to prison on the day the MH370 had left Malaysia.

“There is no mention in the investigation regarding Zaharie’s involvement in politics – I feel it is relevant and should have been addressed,” he added.

“From a pilot’s point of view, MH370’s deviation from its planned route shows that the person flying the aircraft had meticulously planned, and executed an aircraft hijacking.

“It’s also a reasonable assumption that he would stay conscious until the end. Why then does the Malaysian government, and indeed our Australian Transport Safety Bureau (ATSB), insist that this was a “ghost flight” with dead pilots at the end?

“There is little or no evidence to support this supposition.”

The MH370 investigation report has concluded that there is no evidence linking Zaharie to jeopardising the flight that day.

In May, Malaysia called off a privately-funded underwater search for the aircraft after US-based firm Ocean Infinity found no significant new findings.

This was the second major search for the airplane, after Australia, China and Malaysia ended a fruitless A$200 million search across an area of 120,000 sq km last year.

An analysis by the Australian government suggested MH370 ran out of fuel before plummeting – at as much as 25,000 feet a minute – into the water.

Other investigators have speculated that a person was at the controls to the very end, gliding the plane into the ocean beyond the furthest limit of any search area.

A few pieces of wreckage washed up in Africa but no bodies have ever been recovered.

Prime Minister Dr Mahathir Mohamad has since said Malaysia would consider resuming the search if new clues came to light.