The pilot(s) of the AirAsia aircraft did not issue a distress signal, disappeared after an attempt to get permission to fly higher to avoid bad weather or because of heavy air traffic. It was flying at 32,000 feet and had asked for clearance to climb to 38,000 feet. When air traffic controllers granted permission for a climb to 34,000 feet shortly after, no response was received from the aircraft. It is possible that when the request for an altitude change was made, the aircraft was already in trouble.
Speculation among pilots has centred on unconfirmed radar data from Malaysia suggesting the aircraft was climbing at a speed of 353 knots – about 100 knots too slow – which may have led to an aerodynamic stall. That the debris field relatively close to the last known radar plot of the plane also points to an aerodynamic stall, most likely due to bad weather.
It is possible that the crew took too long to request permission to climb, or could have ascended on their own initiative earlier, and that poor weather could have played a part as well. If the weather was so bad, perhaps a return to Surabaya may have been considered.
One possibility was that the plane’s pitot iced up in a tropical thunderstorm, giving the pilots inaccurate readings.
The absence of a distress call may indicate that the pilots may have realised too late they were in trouble and were too busy attempting to bring the aircraft under control to issue send a distress call.
The captain of the flight was a former air force pilot with 6,100 flying hours, and the plane last underwent maintenance in mid-November.
This of course is all speculation. When the CVR and FDR are located this will indicate exactly what has occurred.
Our prayers are with the family and friends of the passengers of this flight.