The lost Malaysia Airlines Flight 370 flew most likely on autopilot for several hours before the crash with the crew incapacitated probably due to hypoxia, an investigation report has revealed.
Released more than 100 days after the plane’s mysterious disappearance and after months of fruitless search, the 55-page analysis by the Australian Transport Safety Board (ATSB) has reviewed the sporadic evidence about the aircraft’s whereabouts, mostly based on satellite and early radar data.
"Given these observations, the final stages of the unresponsive crew, hypoxia event type appeared to best fit the available evidence for the final period of MH370's flight when it was heading in a generally southerly direction," the ATSB report said.
A new search area has been determined, focusing on a spot on the seventh arc established by UK satellite operator Inmarsat. The seven arcs mark zones which the doomed airplane must have crossed and where its satellite systems exchanged regular handshakes with Inmarsat’s spacecraft.
The last, seventh arc, was established upon analyses of a final incomplete handshake, which led investigators to the conclusion it must have taken place shortly before the plane crashed.
"It is highly, highly likely that the aircraft was on autopilot otherwise it could not have followed the orderly path that has been identified through the satellite sightings," Australian Deputy Prime Minister Warren Truss told reporters in Canberra.
"The new priority area is still focused on the seventh arc, where the aircraft last communicated with satellite. We are now shifting our attention to an area further south along the arc,"
Last week, BBC Horizon revealed the search teams haven’t yet reached the area believed by Inmarsat to be the most likely resting place of the ill-fated Boeing 777.
In April this year, en route to this hot spot, the search vessels intercepted what was believed to be signals from the plane’s black boxes. The sea floor in the area was subsequently scanned by an underwater drone with no positive results.
One month later, officials conceded the wreckage was not in area where the supposed pings were intercepted, some 1,600 km (1,000 miles) off the northwest coast of Australia, and the search area would have to be expanded.
Investigators believe the plane was deliberately diverted thousands of kilometres from its scheduled route before eventually plunging into the Indian Ocean. The hypoxia hypothesis would fit this explanation. Citing Tony Cable, a former air accidents investigator, BBC Horizon suggested the plane might have been steered by someone other than the pilots.
In August 2005 a Boeing 737-31S operated by Helios Airways crashed near Athens in Greece. As the aircraft was unresponsive prior to the crash, fighter jets were sent to establish contact. The jets pilots reported seeing a man in the cockpit, who was later determined to be a steward who realised the plane went through a decompression event and tried to steer the plane after the pilots slipped into unconsciousness.
The next phase of the search for MH370 is expected to start in August and take a year, covering some 60,000 square km at a cost of A$60 million ($56 million) or more. The search is already the most expensive in aviation history.
The new priority search area is around 2,000 km west of Perth, a stretch of isolated ocean frequently lashed by storm force winds and massive swells.
Two vessels, one Chinese and one from Dutch engineering company Fugro, are currently mapping the sea floor along the arc, where depths exceed 5,000 metres in parts.
A tender to find a commercial operator to conduct the sea floor search closes on Monday.