Former Sudanese vice-president Abel Alier, a member of the international team probing the crash, said late Friday that black boxes retrieved from Russian-built M1-172 chopper would be flown to Moscow for analysis where a report will be compiled and the boxes then returned to Uganda.
"A group composed of ourselves (Sudanese), Ugandans and Kenyans will accompany the flight data recorder and cockpit voice recorder retrieved from the helicopter debris to Russia," Alier said, adding "We are trying to get all the available information."
Garang died on July 30 when the helicopter taking him back to southern Sudan from Uganda came down. Most believe the accident was due to poor weather, darkness or possible pilot error.
But suspicion over the facts surrounding Garang's death sparked violence between northern and southern Sudanese, leaving at least 130 people dead and prompting Khartoum to form a national committee to investigate the crash with international experts.
Dennis Jones, the US National Transportation Safety Board's chief investigator, said it would take about five days to study the data boxes and estimated the crash investigation could take up to six months.
Broadly, the probe will focus on forensic, ballistics, recorders, operations, airworthiness, air-traffic control and weather, accident site survey, and security and intelligence, according to investigators.