The Air Accidents Investigation Branch (AAIB) has published a report on its investigation into a DJI Matrice 210 crash apparently caused by rain.
The AAIB’s January 2020 Bulletin includes its first eight reports on UAS investigations.
The report on the DJI Matrice 210 crash found that moisture in the fourth motor electronic speed controller (ESC) was the cause of the failure. Moisture in the third motor ESC was found, but whether it played a factor was not determined.
AAIB’s investigation revealed other similar incidents with DJI Matrice 200 Series drones. Moisture ingress into the motors causes a loss of control and vertical descent to the ground.
This, AAIB said, poses a risk to bystanders.
In response it has made two suggestions to the UK CAA: that Matrice 200 users are made aware of the possibility of failure when flying in rain; and that the CAA create regulations limiting the conditions in which drones can be flown over people.
A DJI spokesperson commented: “With safety being our top priority, we take any events regarding failures very seriously.
“The DJI Matrice 200 Series has been independently certified by a third party that it has an IP43 rating. This certifies that ‘water falling as a spray at any angle up to 60° from the vertical shall have no harmful effect’. However, the M200 is not suitable for, and should not be operated in, conditions or precipitation greater than those stated by the certification.
“All users of M200 series drones should refer to our current maintenance guidelines and safety information to help manage their aircraft and maximise flight safety.”