An official report a year on after the disappearance of Malaysia Airlines flight MH370 has done little to solve the mystery of the missing Boeing 777, aviation experts have concluded.
The 584-page report from the Malaysian Government into the March 8 2014 flight, which had 239 people aboard, points to only one anomaly.
This is the fact that the battery of the aircraft's underwater locator beacon had run out more than a year before.
But the report said that the battery on the locator beacon of the cockpit voice recorder was working.
And according to David Learmount, operations and safety editor of Flightglobal aviation news publication, the underwater beacon would not be detectable at the great depths to which the aircraft is thought to have descended.
He went on: "This finding is of no significance. The report really has not explained anything about this flight."
There has been speculation as to the behaviour of the the flight's captain, father-of-three Zaharie Ahmad Shah, 53. He was in command of the plane which had left Kuala Lumpur bound for Beijing.
Today's report said Capt Shah showed no unusual signs of stress before the plane departed, an interim report on the investigation said.
The report went on: "The captain's ability to handle stress at work and home was good. There was no known history of apathy, anxiety, or irritability.
"There were no significant changes in his lifestyle, interpersonal conflict or family stresses."
It also said there were "no behavioural signs of social isolation, change in habits or interest, self-neglect, drug or alcohol abuse" by Capt Shah, his co-pilot Fariq Abdul Hamid, or the cabin crew.
Financial checks also showed nothing abnormal about their gross monthly income and spending pattern. The report said the captain held several bank accounts and two national trust funds. He had two houses and three vehicles, but there was no record of him having a life insurance policy.
Mr Hamid, had two saving accounts and a national trust fund account. He owned two cars and "spent money on the upkeep" of his cars.
"He does not have much savings in his bank account. He has a life insurance policy," it said.
Mr Learmount has maintained that the eccentric routing of the plane, with the aircraft doing almost a U-turn at one point, proved that the plane had been deliberately flown off course.
He said today; "With publication of this report, we still have no explanation of what really happened."
A huge search operation taking place in the Indian Ocean has so far proved fruitless.
Malaysian Prime Minister Najib Razak said: "The lack of answers and definitive proof - such as aircraft wreckage - has made this more difficult to bear.
"Together with our international partners, we have followed the little evidence that exists. Malaysia remains committed to the search, and hopeful that MH370 will be found."
While the country's government has already formally declared the disappearance of the plane as an accident, and said all those on board are presumed dead, relatives of those on the flight have said they are frustrated by the lack of answers.
Ministers from Australia, China and Malaysia are expected to meet next month to decide on the next course of action for the wide-ranging search.
Australian Prime Minister Tony Abbott said the search for MH370 will not end if the scouring of the current search area comes up empty.