'Screaming' alarms filled the cockpit of the AirAsia QZ8501 flight during the critical moments as pilots tried to gain control over the plane before it crashed into the Java Sea on 28 December.
Investigators heard the noise of warning alarms in the recordings of the cockpit voice recorder, and said that pilots' voices were drowned out by the sound of the alarms.
"The warning alarms, we can say, were screaming, while in the background they (the pilot and co-pilot) were busy trying to recover," an investigator told AFP.
The two black boxes - the cockpit voice recorder and the flight data recorder - were pulled out of the sea last week, and Indonesia's National Transportation Safety Committee is set to bring out a preliminary report on the analysis of the plane's black box next week, though details will not be made public.
Investigators have eliminated the probability of a 'terrorism' angle behind the crash, after they found no "suspicious noise or explosion" while analysing the voice recorders.
Indonesia's transport minister had said on Tuesday that the plane likely crashed after it stalled while climbing at the abnormally high rate of 6,000 feet a minute.
"In the final minutes, the plane climbed at a speed which was beyond normal," Transport Minister Ignasius Jonan told reporters.
The investigator told AFP that one of the alarms heard in the cockpit was to indicate that the plane was stalling.
