The Civil Aviation Administration of China (CAAC) said in a statement on 20 April that the black boxes of the crashed China Eastern Airlines Boeing 737-800 plane were severely damaged.
They added that they are still recovering and analyzing the data from the black boxes to ascertain the cause of the plane crash.
CAAC previously confirmed on 26 March that all 132 persons on board the plane were confirmed dead.
CAAC said in a statement on their preliminary crash report that the flight crew was qualified, the weather was fine and the plane was properly maintained.
The last communication the air traffic controllers had with the plane with at 2.16 pm local time, about 5 minutes before the plane started deviating from its flight path.
The last recording of radar information about the plane was at 2.21 pm, before the signal disappeared – the plane was flying at an altitude of about 3,380m at a speed of 1,010km/h, with a heading of 117 degrees.
CAAC added that they have completed the preliminary report (which must be filed to the UN’s ICAO under international rules) although a final report could take more than a year to complete.