This photo provided by by the French air accident investigation authority BEA on Thursday, March 14, 2019, shows one of the black box flight recorder from the crashed Ethiopian Airlines jet, in le Bourget, north of Paris. The French air accident investigation agency has released a photo of the data recorder from the crashed Ethiopian Airlines jet. The agency, known by its French acronym BEA, received the flight's data recorder and voice recorder Thursday. (BEA via AP) Investigators have started studying the cockpit voice recorder of the crashed Ethiopian Airlines jet.
The French air accident investigation agency BEA tweeted that technical work on the recorder began Saturday. The BEA also said work resumed on the flight's data recorders.
The recorders, also known as black boxes, were sent to France because the BEA has extensive expertise in analyzing such devices. Experts from the U.S. National Transportation Safety Board and the plane's manufacturer Boeing are among those involved in the investigation.
In Ethiopia, forensic DNA work has begun on identifying the remains. It may take six months to identify the victims' remains, although death certificates should be issued in two weeks. The 157 who died in the crash came from 35 countries.
A mass memorial service for the dead is planned in Addis Ababa to take place Sunday, one week after the crash. Muslim families have already held prayers for the dead and are anxious to have something to bury as soon as possible.
The Ethiopian disaster and a crash last year in Indonesia were both of the Boeing 737 Max 8 planes. The United States and many other countries have grounded the Max 8s as the U.S.-based company faces the challenge of proving the jets are safe to fly amid suspicions that faulty sensors and software contributed to the two crashes that killed 346 people in less than six months.
This aerial image made from video shows recovery work continuing at the scene where the Ethiopian Airlines Boeing 737 Max 8 crashed shortly after takeoff on Sunday killing all 157 on board, near Bishoftu, south-east of Addis Ababa, in Ethiopia Friday, March 15, 2019. Analysis of the flight recorders has begun in France, the airline said Friday, while in Ethiopia officials started taking DNA samples from victims' family members to assist in identifying remains. (AP Photo/Yidnek Kirubel) The U.S. Federal Aviation Administration said regulators had new data from satellite-based tracking that showed the movements of Ethiopian Airlines Flight 302 were similar to those of Lion Air Flight 610, which crashed off Indonesia in October, killing 189 people.
Both planes flew with erratic altitude changes that could indicate the pilots struggled to control the aircraft. Shortly after their takeoffs, both crews tried to return to the airports but crashed.
Boeing said it supports the grounding of its planes as a precautionary step, while reiterating "full confidence" in their safety. Engineers are making changes to the system designed to prevent an aerodynamic stall if sensors detect that the jet's nose is pointed too high and its speed is too slow.
Investigators looking into the Indonesian crash are examining whether the software automatically pushed the plane's nose down repeatedly, and whether the Lion Air pilots knew how to solve that problem. Ethiopian Airlines says its pilots received special training on the software.
In this photo taken Thursday, March 14, 2019, sister Goreti Kimani consoles brother Chira Kageche at a memorial service for their brother, Catholic priest Rev. George Mukua Kageche, 40, who died in the recent plane crash in Ethiopia, in his home town of Githunguri, near Nairobi, in Kenya. The Rev. George Kageche Mukua was one of 32 Kenyans killed when Ethiopian Airlines flight 302 faltered shortly after takeoff from Addis Ababa and crashed, a numbingly high toll on a flight carrying people from 35 countries. (AP Photo/Sayyid Abdul Azim) 
In this photo taken Thursday, March 14, 2019, Father Michael Wa Mugi lights a candle and signs the book of condolence next to a photo of Catholic priest Rev. George Mukua Kageche, 40, who died in the recent plane crash in Ethiopia, at a prayers ceremony held at his home in Githunguri, near Nairobi, in Kenya. The Rev. George Kageche Mukua was one of 32 Kenyans killed when Ethiopian Airlines flight 302 faltered shortly after takeoff from Addis Ababa and crashed, a numbingly high toll on a flight carrying people from 35 countries. (AP Photo/Sayyid Abdul Azim) 
Two United Nations security officers stand beside a memorial wreath during a ceremony at United Nations headquarters, Friday March 15, 2019, for U.N. personnel that were aboard Ethiopian Airlines Flight ET302. At least 21 U.N. personnel were among the 157 people from 35 countries who died Sunday morning when an Ethiopian Airlines Boeing 737 MAX 8 jetliner crashed shortly after takeoff from Addis Ababa en route to Nairobi, Kenya. (United Nations Photo by Manuel Elias via AP)
Explore further: Ethiopian Airlines says analysis of flight recorders begins