The Australian authority in charge of the search for Malaysia Airlines flight MH370 says the “ghost flight theory” continues to guide its investigations.
The clarification comes amid reports the theory that a rogue pilot deliberately brought down the plane could be revived.
The Boeing 777-200ER aircraft took off from Kuala Lumpur on a scheduled passenger service to Beijing on 8 March 2014, then disappeared with 227 passengers and 12 crew on board.
The Australian Transport Safety Bureau has been searching a 60,000 sq km (46,000 sq mile) area of the southern Indian Ocean off Western Australia, a long but narrow arc determined by calculations of where the plane would have come down after its fuel ran out.
The hypothesis governing the search is that, after it had turned off course and travelled across the Malaysian peninsula, MH370 became a “ghost flight”, travelling on autopilot and crashing when its fuel ran out.
This is supported by analysis of satellite data that the plane continued to fly for more than six hours after contact was lost.
A flaperon from MH370 washed up on remote Réunion Island off the east coast of Madagascar in July last year, but no other trace of the plane has been found.
The search will conclude at some point in June, depending on progress between now and then, and external factors such as weather.
If at that point the plane has not been found, the bureau will have to posit theories as to why it was not in the search area, one of which is that it was piloted down deliberately.
The ATSB chief commissioner, Martin Dolan, told The Times the investigation was not yet at that point, since it was still likely the aircraft would be found in the search area. But if that didn’t happen, “we will have to explain to governments what the alternative is”.
The “rogue pilot theory” would become “a more significant possibility” only if the entire current search area was eliminated.
Dolan was unavailable to comment to Guardian Australia, but a spokesman said the search for MH370 continued to be governed by the theory there was no control input on the aircraft for the last portion of the flight.
“We haven’t seen anything to change our perspective on the search,” he said.
He also said Australia’s responsibility was to look for MH370 in the predetermined area of the southern Indian ocean.
Malaysian authorities had been tasked with investigating what happened on the flight, and he could not comment on how that investigation was progressing.
“It is not ATSB’s role to put forward theories about what may have happened or why. Mr Dolan has indicated the sorts of considerations that might need to be addressed in a report to governments at the conclusion of the search.
“As set out in the reports on our website, the ATSB is searching on the basis that there were no control inputs at the end of the aircraft’s flight.
“Any analysis or conclusion based on the results of our search are matters for the Malaysian investigations.”
In late January, the Malaysian transport ministry announced that a piece of suspected plane wreckage found off the coast of southern Thailand days earlier had not belonged to flight MH370.
