AirAsia flight QZ8501: Aircraft's behaviour before crash 'on the edge of logic', according to expert

Only eight bodies have been recovered from the crash

Indonesian Air Force personnel during a search operation for the victims of the crashed AirAsia plane over the Java Sea, 1 January 2015 (EPA)

AirAsia flight QZ8501, which crashed into the Java Sea on Sunday, behaved in ways “bordering on the edge of logic”, according to an Indonesian aviation expert.

Comments from various experts come as France's crash investigation agency said its specialist black box search team and equipment would arrive early Friday at the search area for the AirAsia flight. The black box will reveal what happened in the final moments of the crash, as the truth behind the cause is still unknown.

Only eight victims have been recovered from the Java Sea despite a a brief window of clear conditions on Thursday. Officials say 162 people died the plane crashed on route from Surabaya to Singapore on Sunday.

Indonesian aviation analyst Gerry Soejatman believes the aircraft rose up as fast as a fighter jet and then dropped back into the ocean almost vertically into the water.

And the extreme weather which Airbus 320-200 encountered meant the pilots were helpless to save the passengers and crew on-board, Soejatman told Fairfax media after he examined figures leaked from the official air crash investigation team.

He said “It’s really hard to comprehend [the plane acted in a way] bordering on the edge of logic,” as it plunged into the water “‘like a piece of metal being thrown down.”

Mr Soejatman believes the crash occurred because the aircraft was caught in a severe updraft, followed by an equally severe ground draft, with the leaked figures showing that it climbed at a staggering rate of 6000ft to 9000ft per minute.

The aircraft then fell at 11,000ft a minute, with bursts of up to 24,000ft – in marked contrast to regular circumstances, when a plane would climb between 1000ft to 1500ft on a sustained basis, gaining 3000ft in a burst.

“You can’t do that at altitude in an Airbus 320 with pilot action,” he argued.

In contrast, aviation expert Peter Marosszeky, from the University of NSW, told the Sydney Morning Herald that the extremely low speed of the aircraft’s descent - as low as 61 knots - would suggest the plane was heading almost straight down, explaining why it has been found in water just 10km from its last point of radar contact.

Mr Marosszeky surmised that a climb rate of at least 6000ft a minute would indicate a “severe weather event,” because that rate of climb was a ‘domain for jet fighters.’

But both experts agree that the jet plunged into the water almost vertically because of a freak weather pattern that placed it under extraordinary force.

Meanwhile, Dudi Sudibyo, a senior editor of aviation magazine Angkasa instead claimed that the pilot managed to land on the sea before the craft was overwhelmed, the Mirror reported.

He suggested the plane landed safely as a heavy impact would have set off emergency locator transmitters on board – but there is no evidence this happened.

The craft was then swamped before sinking below the waves due to the stormy weather, he claimed.

Earlier in the week, AirAsia chief executive Tony Fernandes suggested the jet had encountered "very unique weather” and suggested climate change may be making flights more risky, particularly in the tropics.