Passengers 'conscious until impact'
The captain of Indonesia AirAsia Flight QZ8501 was out of his seat, preoccupied with computer problems, when his plane was swept up by a massive storm updraft.
The plane then stalled and plummeted into the Java Sea, killing all 162 aboard.
Sources close to the crash investigation said that Capt. Iriyanto was out of his seat trying to disconnect the critical dual flight augmentation computers.
This is done through the circuit breakers behind and above the pilots, requiring the non-flying pilot to leave his seat.
Disconnecting the augmentation computers removed a host of features, including the critical cockpit speed warnings and protections.
It also makes the A320 "harder to fly", according to an A320 check and training captain, who did not wish to be named.
"It is highly likely that the French co-pilot, Remi Plesel, who was flying the A320, was preoccupied with the computer problems and not paying attention to the radar and missed the severity of the weather ahead," the A320 pilot said.
Indonesia AirAsia had been having problems with the augmentation computers. The Singapore Straits Times reported there were nine write-ups in the plane's technical log for issues with those computers last year alone.
The co-pilot on that December 28 flight from Surabaya to Singapore had 2247 hours of experience and the captain was a 20,537-hour veteran.
These types of crashes are termed in the industry "light-bulb crashes", referring to the fact a simple malfunction that distracts all the crew can lead to the loss of the plane.
More details have emerged of the passengers and crew's terrifying ride before the plane hit the sea.
When the A320 flew into the storm's updraft, it soared at up to 6000ft a minute before stalling and then turning to the left and spiralling down at up to 24,000ft a minute.
It was thought the G-forces would have rendered passengers unconscious, but pilot experts have said they "would have been conscious through the ordeal until impact".
Ertata Lananggalih, an investigator with Indonesia's National Transportation Safety Committee, said the "pilots were conscious when the manoeuvres happened".
Indonesia is not releasing the preliminary report into the crash for public scrutiny, although all countries involved have received the document.
Authorities have now recovered 70 bodies but have been unable to lift the plane's main cabin from the sea.
