An independent analysis of previously secret data from missing Malaysia Airlines flight MH370 has confirmed that the Boeing 777 was in a spiral dive in its final moments and it is unlikely that anyone was in control.

The analysis released yesterday by the Independent Group, a team of aviation and mathematical experts, confirms the Australian Transport Safety Bureau’s long-held view on the plane’s disappearance on March 8, 2014 with 239 people aboard.

Conspiracy theorists have suggested that the Boeing 777 was under the control of one of the pilots and “landed” on the ocean.

The search for the plane, which has been led by Australia, was suspended this year by Malaysia despite a new area being identified as the potential location of the wreckage.

That new area of 25,000sqkm, identified by reverse drift analysis of debris, is just to the north of the original search area.

In his review of the new data, Victor Iannello of the Independent Group says “considering that the newly available data generally support the conclusions of the official investigators, it remains a mystery as to why Malaysia withheld the data for so long, and why it chose to release the data at this time”.

The data contained all the information transmitted by an Inmarsat satellite link on the plane’s previous flight, MH371, from Beijing to Kuala Lumpur.

This enabled researchers to identify any aspects that were common to both flights and eliminate anomalies in MH370’s communications.

Camera Icon Debris from MH370 washed up on the French Indian Ocean island of La Reunion in July, 2015. Credit: AFP

Mr Iannello said that “the previous flight, MH371, seems to have been normal in all respects”.

“Using the satellite data from MH371, we have a higher level of confidence that for MH370 the aircraft was in an increasingly steep descent at its final log-on” to the satellite just before it crashed into the ocean.

CSIRO scientists are increasingly confident about drift modelling used to predict the location of MH370 and say a resumed search would need to target a relatively small area.

A CSIRO report released in April concluded a region in the Southern Indian Ocean near the so-called seventh arc and latitude 35°S was the likely resting place of the airliner.

The finding was consistent with findings in 2016 by a group of international experts that the airliner is probably in a 25,000 sq. km area north of where the plane was originally thought to be.

The CSIRO team led by Dr David Griffin has since made further refinements and narrowed down the prospective search area after looking more closely at an ocean current flowing towards the northwest in the weeks after the crash.