Chinese authorities have recovered the second black box from the China Eastern Airlines jet that plunged into a mountainside last Monday with 132 people on board.
The discovery, reported by state media, follows the retrieval of the cockpit voice recorder (CVR) on Wednesday.
Mystery remains as to what caused the Boeing 737 plane to suddenly nose dive as it headed from Kunming to Guangzhou last Monday, killing 123 passengers and nine crew.
It appears to have crashed into a remote hillside at around 350mph and while investigators have found a black box it is uncertain if data can be retrieved from it due to its damaged state.
Search teams have been looking through the debris at the crash site over the days since, for clues as to what happened.
Horrifying footage shows the aircraft nosediving to the ground - with one aviation expert saying a technical fault would not have caused such a sudden and rapid manoeuvre.
Flight MU5735 had departed the city of Kunming at 1.11pm local time (5.11am GMT) and was due to arrive in Guangzhou at 3.05pm.
But as it prepared to descend, the aircraft lost altitude and dropped thousands of feet in seconds.
Despite momentarily regaining height at close to 9,000ft, it hit the ground at an estimated 350mph in a hilly woodland area near the city of Wuzhou.
China Eastern has grounded all of its Boeing 737-800s as a precaution.
Black boxes, which are not actually black but high-visibility orange, have become synonymous with the quest for answers when planes crash.
Their aim is not to establish legal liability but to identify causes and help prevent accidents.
Upon the recovery of black boxes, technicians peel away protective material and carefully clean connections to make sure they do not accidentally erase data.
The audio or data file must be downloaded and copied.
The data itself means nothing at first. It must be decoded from raw files before being turned into graphs.
Investigators sometimes use "spectral analysis" - a way of examining sounds that allows scientists to pick out barely audible alarms or the first fleeting crack of an explosion.
Both of the China Eastern jet's black boxes were manufactured by Honeywell, Chinese accident investigator Mao Yanfeng told reporters on Wednesday, without naming the models.
The CVR installed at the rear of the passenger cabin had a recording time of two to three hours, with four channels including the captain and first officer, a backup channel and one for ambient noise in the cockpit, he said.
The China Eastern plane crashed 66 minutes after take-off.
The FDR at the back of the cargo bay had a recording time of 25 hours including around 1,000 data parameters, Mao said.
Interim reports into a crash, using information recovered from a black box, are published after a month but are often sparse.
Deeper investigations take a year or more to complete.
Experts say air accidents usually result from a combination of factors.
