One of the two black boxes was found badly damaged by China Eastern flight MU5735 which crashed on Monday.
The Boeing 737-800 was traveling between Kunming and Guangzhou, China, with 132 people on board, when it crashed in the mountains of Guangxi.
It has since been confirmed that there were no survivors.
Director of the Aviation Safety Bureau of the Civil Aviation Authority of China, Zhu Tao, said the outer casing of the black box suffered the most damage while the rest of the device is “relatively intact”.
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Mr Tao said the device would be sent back for further analysis which would offer insight into the cause of the crash.
“This will provide important evidence as to the cause of the crash,” he added. he said.
In order to better understand what happened, investigators will continue to search for the flight data recorder.
Civil Aviation Authority accident investigation director Mao Yanfeng said a large-scale operation was underway to locate the second black box.
The wet weather and location hampered search efforts, with water filling the hole left by the plane’s impact.
Fire and Rescue Service chief Zheng Xi said the invasive grass and weeds had made search efforts more difficult.
“The area is overgrown with weeds and the terrain is steep,” he said, adding, “With the rain, visibility was poor, introducing some degree of difficulty to the rescue operation.” did he declare.
So far, search teams have managed to locate a number of wallets, ID cards and bank cars among the debris.
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