Authorities now have a much better understanding of where missing Malaysian Airlines flight MH370 is located but still do not know why it crashed, a new report has revealed.
In its final report into the search for the missing aircraft, the Australian Transport Safety Bureau (ATSB) said the search area had been considerably narrowed to an area of less than 25,000 square kilometres that had the "highest likelihood" of containing MH370.
"The understanding of where MH370 may be located is better now than it has ever been," the report found.
The aircraft was lost during a flight from Kuala Lumpur to Beijing on March 8 2014, carrying 227 passengers and 12 crew members.
Its disappearance is one of the greatest mysteries in aviation history.
The surface and underwater searches which followed off the coast of Western Australia were the biggest in history.
"At the time the underwater search was suspended in January 2017, more than 120,000 square kilometres of seafloor had been searched and eliminated with a high degree of confidence," the report found.
The ATSB said debris found on islands in the Indian Ocean and on the coast of Africa helped establish that the aircraft was "not configured for a ditching at the end-of-flight".
Recent re-analysis of satellite imagery taken two weeks after the aircraft disappeared had also identified objects which may have been debris from MH370, it found.
The Malaysian Government was continuing work on the investigation into the circumstances surrounding the loss of the aircraft, the ATSB added.
"It is almost inconceivable and certainly societally unacceptable in the modern aviation era with 10 million passengers boarding commercial aircraft every day, 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," the report said.
However, the ATSB said reasons for the loss of the aircraft "cannot be established with certainty until the aircraft is found".
"The ATSB expresses our deepest sympathies to the families of the passengers and crew on board MH370," the bureau said.
"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."