JAKARTA:Indonesia's air accident investigator will brief relatives of the 62 victims of last month's Sriwijaya Air crash in Jakarta on Wednesday morning ahead of the release of a preliminary report in the afternoon, a family member told Reuters.

The briefing follows one held for families on Tuesday in Pontianak, the doomed flight's destination, and comes as divers search for the missing memory unit from the plane's cockpit voice recorder.

The 26-year-old Boeing Co 737-500 jet crashed into the Java Sea shortly after take-off from Jakarta, marking Indonesia's third major airline crash in just over six years and shining a spotlight on the country's poor air safety record.

Rafik Alaydrus, whose wife died in the crash, said investigators on Tuesday told family members that the cause had not been determined but that various factors, including the plane's autothrottle system, were being investigated.

"For family of victims, we do not understand about technical issues," he said. "We responded this incident had happened and the victims should get their right compensation."

Investigators quickly located and read the plane's flight data recorder (FDR) and sent parts of the plane, including the autothrottle system that controls engine power automatically, to the United States and Britain for examination.

Citing sources close to the investigation, the Wall Street Journal last month reported the FDR data showed the autothrottle system was not operating properly on one of the plane's engines as it left Jakarta.

Instead of shutting off the system, the FDR indicated the pilots tried to get the stuck throttle to function, the WSJ said. That could create significant differences in power between engines, making the jet harder to control.

National Transportation Safety Committee (KNKT) Chief Soerjanto Tjahjono last week said that the WSJ report was incorrect and that more information would be provided in KNKT's preliminary report.

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.