What happened
On 16 January 2022, at approximately 2003Z, a DJI Matrice-200 remotely piloted aircraft, registered ZT-WUL, was conducting a night-time surveillance mission near Ogies, Mpumalanga. The flight was being operated under visual line of sight (VLOS) conditions as part of a security effort at the Glencore Goedgevonden Mine to track individuals suspected of stealing power cables.
While the pilot was monitoring the suspects from roughly 500 metres away, the aircraft experienced a critical malfunction 12 minutes and 45 seconds into the flight. The drone began to spiral downward and crashed at an altitude of approximately 41 metres above ground level. Following the impact, the aircraft lost connection with the controller. Although the pilot searched the area, only fragments of the rotor and the tracking unit were recovered; the main body of the aircraft was not found at the crash site.
The investigation
SACAA AIID examined the operational records and technical data provided by the operator. The investigation confirmed that the pilot held a valid Remote Pilot Licence (RPL) with the appropriate multirotor and VLOS endorsements, and the operator possessed a valid Letter of Approval (LOA).
Technical analysis of the flight data revealed that the aircraft's internal compass experienced interference. This interference was linked to the motor spooling up, which disrupted the drone's navigational sensors.
Findings
- The primary cause of the accident was the failure of the left front motor, which led to the aircraft losing stability and spiralling into the ground.
- A contributing factor was compass interference triggered by motor activity.
- There were no injuries reported as a result of the incident.