THE mystery over the fate of Malaysia Airlines Flight 370 and its 239 passengers is “almost inconceivable”, says a report by the body which co-ordinated the massive, 1,046-day search.

The Australian Transport Safety Bureau’s final report on the search concedes that authorities are no closer to knowing the reasons for the plane’s disappearance, or its exact location.

The Boeing 777 carrying 227 passengers and 12 crew disappeared soon into its flight from Kuala Lumpur to Beijing on March 8 2014.

A 52-day surface search covered an area of several million square miles in the Indian Ocean west of Australia, before an underwater search mapped 274,000 square miles (710,000 sq km) of seabed at depths of up to 20,000ft (6,000m). They were the largest aviation searches of their kind in history, the bureau said.

“It is almost inconceivable and certainly societally unacceptable in the modern aviation era [...] for a large commercial aircraft to be missing and for the world not to know with certainty what became of the aircraft and those on board,” said the bureau.

“The ATSB expresses our deepest sympathies to the families of the passengers and crew on board MH370. We share your profound and prolonged grief, and deeply regret that we have not been able to locate the aircraft, nor those 239 souls on board that remain missing.”