But Duncan Steel, a scientist on a panel of experts that has advised the Australian government, said the arc might have been drawn too far south. Investigators have assumed the plane was at cruising altitude when it sent its last signal, he said, but if the plane had started descending earlier as it ran low on fuel, it would have covered less distance before it hit the ocean.

Investigators said on May 12 that two pieces of debris recovered in March from South Africa and from Rodrigues Island, part of Mauritius, were “almost certainly” from the missing plane. But neither part — a piece of the interior panel in the main cabin and a piece of engine covering — provided significant information about the aircraft’s final location.

Australia’s minister of infrastructure and transport, Darren Chester, announced on May 26 that two more pieces of debris had been found in Mauritius and another in Mozambique that would also be examined for possible links to the missing aircraft.

The Australian government said on Friday that four more pieces of debris, three found on Madagascar and one on a southern Australian island, would be checked to determine whether they came from the missing plane.

Three other pieces linked to the plane were discovered on African beaches last year and early this year. One was identified as clearly belonging to the right wing, while another was identified as “almost certainly” coming from the right wing and a third as “almost certainly” coming from the right side of the tail.

The accumulation of parts from the aircraft’s right side has led some to suggest that the plane may have changed course before it crashed, possibly under the control of a conscious pilot.