Cockpit voice recorder
An Indonesian official looks at the cockpit voice recorder of AirAsia QZ8501 during news conference at the National Transportation Safety Committee office in Jakarta Jan. 13, 2015. Reuters/Pius Erlangga

Investigators examining the crash of AirAsia Flight 8501 will now focus on human error and aircraft damage as possible reasons for the plane's downing, officials said Tuesday, a day after ruling out terrorist involvement as a cause.

Indonesia's National Transportation Safety Committee (NTSC), which is investigating the incident, reportedly said that it will release a preliminary report about the crash on Jan. 28. Earlier, investigators had said they found no evidence linking terrorism to Flight 8501’s crash, after analyzing data from the cockpit voice recorder.

"We didn't hear any voice of other persons other than the pilots," Nurcahyo Utomo, an investigator, told Reuters. "We didn't hear any sounds of gunfire or explosions. For the time being, based on that, we can eliminate the possibility of terrorism." Utomo also reportedly said that he could not reveal Flight 8501’s final moments due to legal issues.

An investigator had told BBC on Monday that there were indications in the recordings that the plane had encountered bad weather, but did not reveal any other detail. Indonesia's meteorological agency had previously said that bad weather may have caused the crash after the plane went off radar following a request from the pilot for a change of course due to unfavorable weather.

Andreas Hananto, another NTSC investigator, reportedly said that the final minutes were full of "sounds of machines and sounds of warnings," which needed to be filtered to get a complete transcript of what was said in the plane's cockpit, from the voice data recorder.

NTSC investigator Ertata Lananggalih told Agence France-Presse that no other detail about the contents of the flight data recorders would be released before the preliminary report.

Divers are currently attempting to reach the fuselage at the bottom of the Java Sea where the bodies of several passengers are expected to be trapped, but search operations are being hindered by rough seas and strong currents.

The Airbus A320-200, with 162 people on board, crashed on Dec. 28, about halfway through its flight from Surabaya, Indonesia, to Singapore's Changi International Airport. So far, 53 bodies have been recovered from the sea and 45 have been identified.