The flight recorders from the Indonesian plane that crash-landed in Java on Wednesday have arrived in Australia for analysis.
The retrieved black boxes were immediately flown to Australia
Experts are examining the black boxes to piece together what happened when the Garuda Airlines Boeing 737-400 tried to land at Yogyakarta airport.
Investigators say they hope for initial results within a few days.
Indonesia says it has identified the 21 people who died, among them five Australians. There were 119 survivors.
Australia has confirmed that four of its staff in Indonesia as well as a Jakarta-based financial journalist are among the missing, but said it had yet to positively identify the bodies.
Both technical failure and human error have been cited by the authorities as possible causes of the crash.
But Capt Stephanus Geraldus, president of the Garuda pilot's association, said no conclusions should be drawn until the flight recorder data had been analysed.
The pilot had said he was caught in a "powerful downdraft" just before landing, Capt Geraldus told the Associated Press.
Australia's Federal Police Commissioner Mick Keelty said he too had heard of the pilot's account, from Indonesian investigators, but like Capt Geraldus cautioned against speculation.
"We really won't know until all the data is known and all the exhibits put back together," he told Australia's ABC news.
Both the cockpit voice recorder and the flight data recorder were damaged in the fire that engulfed the plane, but crash investigators said they were confident they could still recover the information from them.
"We're just seeing how the crew were operating on approach, whether there was anything unusual, any warnings on the flight deck," Neil Campbell of the Australian Transport Safety Bureau said.
"From the flight data recorder we can tell the aircraft's speed on approach, its rate of descent, engine settings, flap settings, things like that. It's all very useful information."
Flight GA200 crash-landed about 440km (270 miles) south-east of the capital, Jakarta.
The front wheel of the plane was on fire as it landed, causing it to veer off the runway and hit a boundary fence, the operations chief at Yogyakarta airport said.
He said an engine had then broken away from the plane and the fuselage burst into flames. The aircraft came to rest in the middle of a rice field.
Among those on board were an Australian delegation of officials and reporters covering a visit to Indonesia by the Australian Foreign Minister, Alexander Downer, who was expected on the next flight.
Two members of the Royal Australian Airforce who survived the crash said the plane came in to land too fast and then bounced along the ground.