Of the more than 20 items of debris that investigators are interested in, closest scrutiny has been given to several flap sections confirmed to have come from MH370, a Boeing 777-200ER.
Damage analysis was performed on these to determine the state of the aircraft prior to it entering the water. This is important because the investigation’s official line has always been that the aircraft made an uncontrolled decent.
However, many have argued that a pilot was still in control, and ditched the aircraft intentionally. This view received support when it was revealed that captain Zaharie Shah had plotted a course on his home flight simulator to the Southern Indian Ocean – the focal point of search efforts.
Examining a crack in a fibreglass seal pan, investigators concluded that the damage was probably caused by an impact with the support track, along which flaps are extended and retracted on rollers.
“That damage provided further evidence of the support track position within the flap seal pan cavity, indicating that the flaps were retracted at the point of fracture and separation from the wing,” said the Australian Transport Safety Board, which is co-ordinating the investigation.
Retracted flaps would mean that the aircraft was in cruise mode, which backs the official line that there was no controlled descent.
The ATSB also said: "Additional analysis (of) the final satellite communications to and from the aircraft is consistent with the aircraft being in a high and increasing rate of descent at that time."
Even so, it is still possible the aircraft was deliberately flown until it ran out of fuel, which would again suggest a murder-suicide bid.
Evidence for motivation, however, remains scant.