Malaysian investigators are no “closer to knowing” what caused the disappearance of flight MH370 despite a 15,000-page report.

The Malaysia Airlines plane disappeared four years ago on a routine trip from Kuala Lumpur to Beijing.

It had 239 people on board, including six Australians.

A report into the flight’s disappearance has been handed down in Malaysia but it’s still not known what happened.

Lead investigator Kok Soo Chon says it’s possible the plane was taken over.

Investigators found the plane wasn’t being controlled remotely or put into auto-pilot, but they say they’ll never have a definitive answer unless the wreckage is found.

Final report into disappearance of #MH370 with 239 passengers on-board just released by Malaysian Safety Investigation team. Says aircraft did turn back under manual control & cannot discount external forces taking control. @MAS @9NewsAUS https://t.co/4sgdFmxtOn pic.twitter.com/CgMMtvJjnX

— Ross Greenwood (@Ross_Greenwood) July 30, 2018

Former Qantas Head of Safety and AvLaw International Founder Ron Bartsch tells Ross Greenwood it’s “unprecedented”.

“It is quite amazing and unprecedented that in this day and age we can just have a civil airline disappearing and four years later, and a 15,000-page report, still no conclusive… or even ideas as to what went wrong.

“What really amazes me is the fact the Chinese air traffic controllers did not follow international protocol and raise the alert phase as soon as they realised that the aircraft hadn’t reported at the appropriate time.”

Mr Bartsch says the “most damning” part of the report is “there is no closure”.

“We’re still no closer to knowing.”

Click PLAY below to hear the full interview