What happened
On 2 November 2021, a DJI Matrice M210 V2 remotely piloted aircraft, registered as ZT-UWG, was conducting an aerial inspection at the Thungela Shared Services facility in Witbank, Mpumalanga. The flight was being operated under visual flight rules (VFR) in accordance with Part 101 regulations.
After successfully completing an initial flight, the pilot commenced a final mission. While flying at approximately 400 feet above ground level and roughly 700 meters from the landing zone, the pilot observed the aircraft malfunctioning while monitoring the transmitter screen. The drone immediately entered a rapid, uncontrolled descent. No high winds or prior warnings were noted by the pilot, and the aircraft's battery was at 85% capacity at the time of the incident. The aircraft subsequently lost line-of-sight and crashed in a nearby field, resulting in the destruction of the aircraft.
The investigation
SACAA AIID reviewed the flight data and maintenance records provided by the operator. The investigation examined the aircraft's internal logs, including the Inertial Measurement Unit (IMU) and air data. Analysis of the flight logs revealed that the aircraft experienced a loss of thrust and recorded errors related to the electronic speed control (ESC) and the smart motors.
While the IMU logs confirmed that no impact occurred during the flight itself, they showed the aircraft began falling at an accelerated rate. The investigation also reviewed the pilot's credentials, noting the pilot was fully qualified with a valid Remote Pilot Licence and appropriate multirotor endorsements. Maintenance and pre-flight records for the operator were also reviewed, and no issues were found regarding the power systems or sensors prior to the flight.
Findings
- The primary cause of the accident was an ESC or motor failure during flight, which caused the aircraft to lose synchronization and enter a terminal descent.
- A hardware or component failure acted as a contributing factor to the loss of control.