MH370 plunged into the ocean at high speed—up to 20,000 feet a minute—reinforcing analysis that the missing Malaysia Airlines jet crashed in the current search zone, a report said.
The Boeing 777 disappeared on March 8, 2014 en route from Kuala Lumpur to Beijing with 239 people onboard.
An extensive underwater hunt in the southern Indian Ocean has not yet found the crash site, fuelling speculation it may be outside the current search zone, particularly if someone was at the controls at the end of the flight.
A manned plane could have been glided down, allowing it to enter the water outside the 1,20,000 square kilometre area being searched, some experts have suggested.
But extensive testing by aircraft manufacturer Boeing and new Australian defence department data analysis both suggest that regardless of the possible actions of one or both of the pilots the jet dived into the ocean at high speed, The Australian reported.
Once MH370 ran out of fuel and the engines flamed, it slowed before plunging down towards the water in a series of swoops dropping from 35,000 feet at a rate of between 12,000 feet a minute and 20,000 feet a minute, Boeing said, according to the report.
The sharp dive was confirmed by a new data analysis by Australia's defence department involving signals sent automatically between the plane and a satellite, the head of the agency leading the MH370 hunt said.
Australian Transport and Safety Bureau chief Greg Hood said this supported the view MH370 "was likely to have crashed in the 120,000 square kilometre area now being searched," the paper said.
The area was defined under the ATSB's "most likely" scenario that no-one was at the controls and the plane ran out of fuel.
"The Australians leading the search do not doubt that the pilot may well have been responsible for the jet's disappearance but they say critics of the search strategy are wrong to assume that they are looking in the wrong place," the report added.
Malaysian officials said last week that one of the pilots used a home-made flight simulator to plot a very similar course to MH370's presumed final route, but warned this did not prove he deliberately crashed the plane.