AAIB investigation to DJI Matrice 210 RTK (UAS, registration n/a)
DJI Matrice 210 RTK (UAS, registration) n/a Loss of power due to erroneously high reported battery state of charge, Manchester Piccadilly Gardens, 20 October 2018.
Summary:
The operator deployed the DJI Matrice 210 RTK unmanned aircraft system in the City Centre of Manchester. Whilst the aircraft was in a static hover at 260 ft above the takeoff point with an estimated remaining flight time of 12 minutes and 9 seconds displayed on the controller, the aircraft suddenly descended and slewed sideways uncontrollably. It hit the ground causing extensive damage to the airframe, batteries and cameras. No persons or other property were hit by the aircraft.
Analysis confirmed that one of the batteries was indicating an erroneously high state of charge (SOC) and the aircraft had initiated automatic landing due to critically low battery voltage. It subsequently lost all power less than 2.5 seconds later, which resulted in an uncontrolled descent followed by impact with the ground.
The cause of the erroneously high SOC is discussed in the report on the accident to DJI Matrice 210 on 4 September 2018 (ref EW/G2018/09/04, AAIB Bulletin 11/2019).
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