Crews searching through the wreckage of the crashed China Eastern Boeing 737-800 jet have found the second black box.
Flight MU5735 crashed into a mountainside in southern China on March 21, killing all 132 people on board. Nine crew members are among the dead.
The black box, which records flight data, could shed light on the cause of the crash. It has been sent to Beijing for analysis, state media reported.
The first black box, the cockpit voice recorder, was delivered to the Chinese capital after being found last Wednesday.
The crash was the deadliest aviation disaster on mainland China for 28 years.
The plane was heading to coastal Guangzhou from the south-western city of Kunming when it dived from its cruising altitude at about the time it should have started its landing descent.
It briefly appeared to pull out of its nosedive before resuming its plunge to Earth, flight tracking website FlightRadar24 found. Its data showed the aircraft was plummeting about 9,450 metres a minute.
The pilots did not respond to repeated calls from air-traffic controllers and nearby planes during its rapid descent, authorities said.
It was too soon to determine the cause of the accident because crashes often result from a combination of factors, experts said.
The second black box was dug out of a slope at the crash site at about 9.20am on Sunday. Conditions were muddy because it rained in recent days.
The device, part of which was badly damaged, was recovered 1.5 metres underground and 40 metres from the point of impact, said Zhu Tao, head of aviation safety at the Civil Aviation Administration of China.
"Civil aviation investigators at the site confirmed that the storage unit of the flight data recorder has been found," Mr Zhu said in Guangxi.
"Parts of the recorder were seriously damaged, but the outside of the storage unit was in fairly good condition."
The crash was the deadliest since in 1994, when a China Northwest Airlines flight from Xian to Guangzhou crashed, killing all 160 people on board.
The Flight MU5735 disaster has shocked China, with social media users sharing what little was known about the crash on several platforms.
China's cyberspace watchdog ordered social media platforms and websites to clamp down on rumours, conspiracy theories and mockery of the disaster.
Authorities have barred users and closed accounts to tackle more than 167,000 rumours, from the deaths of seven directors of a company to prophesies of a plane crash by the end of March.
China is leading the crash investigation. The US has been invited to take part, because the Boeing 737-800 was designed and manufactured there.
The US National Transportation Safety Board said it was working with American and Chinese authorities to resolve issues around visas and Covid-19 quarantine rules before participating.
