Perth

THE search for Malaysia Airlines' missing Flight 370 on the floor of the southern Indian Ocean is nearing an end with no sign of the plane in the area that investigators had concluded it most likely went down, prompting a last-ditch reassessment of assumptions used to calculate its final descent and draw the search zone.

At issue are estimates of how far the plane may have travelled after it ran out of fuel, notably whether it followed a tight or broad spiral down as it fell or glided towards the ocean, officials said. "We're really doing further work to test our assumption about the end of flight, which defines our search area," said Martin Dolan, chief commissioner of the Australian Transport Safety Bureau. "It's really testing to make sure we haven't missed anything, and that our assumptions remain valid."