Indonesia has recovered the cockpit voice recorder of the Sriwijaya Air jet that crashed in January.
Indonesia's air accident investigator said on Wednesday it could take up to a week to be able to listen to the recording.
All 62 people on board the Boeing plane were killed when it crashed into the Java sea minutes after take off from Jakarta.
A preliminary report by investigators showed that the plane had an imbalance in engine thrust.
The report included information from the flight data recorder, but now with the cockpit voice recorder, investigators could learn more about the pilots' actions during the brief flight.
Indonesia's National Transportation safety chief Soerjanto Tjahjono explained what would happen next:
"We will bring the Cockpit Voice Recorder to the lab to process. It will take around three days to one week to read it. After that, we will do a transcript and match with the information extracted from the Flight Data Recorder, to find out the situation that unfolded in the cockpit"
Divers first found the casing and beacon of the voice recorder within days of the crash.
They then spent nearly three months searching for the memory unit in relatively shallow but muddy waters.
A navy official said it had been found under a meter of mud.
Safety experts say most air accidents are caused by a combination of factors that can take months to establish.
Under international standards, the final report is due within a year of the crash.