The National Transportation Safety Commission (KNKT) head, Tatang Kurniadi, says that his institution has downloaded the recording from the voice cockpit recorder (CVR) of AirAsia flight QZ8501, which crashed into the Java Sea on Dec 28 last year.
"We have successfully downloaded the pilots' dialogue from the CVR. The total CVR recording is two hours and four minutes," Tatang said in Jakarta on Friday, as quoted by kontan.co.id.
"The investigators are currently transcribing the recording, while data from the [Airbus A320] plane's FDR [flight data recorder] is now being converted."
He said that the KNKT investigation team was also preparing a preliminary report on the crash of the Surabaya-Singapore flight that would be sent to the International Civil Aviation Organisation (ICAO).
"The preliminary report consists of information and initial analysis of the crash, 30 days after the accident occurred," he explained.
He emphasised that the intention of the investigation was not to blame any party but to improve the air transportation system.
Meanwhile, earlier on Thursday bad weather and poor underwater visibility on Thursday prevented Indonesian navy divers from searching inside the large chuck of AirAsia jet wreckage that is believed to be the fuselage.
At least 15 divers descended to the seabed at a depth of 28 meters to examine the piece of wreckage spotted Wednesday, calculate its weight and search for bodies. They were unable to do so because of the weather and sea conditions, said Suryadi Bambang Supriyadi, the operation director at the National Search and Rescue Agency.
He said it appeared that some parts of the fuselage have been covered with silt. When bodies are found, the divers would try to put them in individual body bags, which rescuers on ships would then hoist to the surface, he said as quoted by Reuters.
The 30-meter-long section of the plane body with a wing attached was sighted on the bottom of the Java Sea by a Singaporean navy ship.
Only 50 bodies have been recovered since the plane disappeared from radar and crashed in the sea Dec. 28 en route from Surabaya, Indonesia, to Singapore. Most of the 162 victims are Indonesian.
Rescuers believe that most of the bodies are inside the main fuselage.
Search and Rescue Agency chief Henry Bambang Soelistyo said the large piece of wreckage would be lifted from the seabed after the search for bodies was no longer considered effective.
Nine aircraft and 10 ships conducted search operations Thursday. Two US ships and one from Singapore have left, Soelistyo said.
The destroyer USS Sampson and combat ship USS Fort Worth left for other assignments after contributing more than 650 search hours for the AirAsia flight.
"The US was extremely proud to assist" the search effort, US Ambassador to Indonesia Robert O. Blake said.
"We are all pleased with the recovery of the black boxes and location of portions of the plane that we hope will shed some light on the cause of this tragedy."