What happened
On the night of 20 February 2023, a DJI Mavic 2 Enterprise Advanced with registration ZT-YIT was deployed for aerial surveillance at the Welverdiend Pump Station in Springbok, Mpumalanga. The mission was being conducted under Beyond Visual Line of Sight (BVLOS) regulations for mining area monitoring.
Following a standard pre-flight inspection that showed no anomalies and a full battery charge, the pilot launched the aircraft. Approximately three minutes into the flight, the controller unit began displaying low battery voltage warnings. Despite the pilot attempting to clear the error and initiating the return-to-launch (RTL) function, the controller screen suddenly went black, severing the link with the aircraft. A subsequent attempt to locate the drone using a second RPA was unsuccessful, and the aircraft remains missing.
The investigation
SACAA AIID examined flight logs and data from the operator's AIRDATA and Mission Planner software. The investigation confirmed that the pilot was properly licensed for BVLOS and multirotor operations and held a valid medical certificate. The operator also held the necessary approvals for the mission.
Analysis of the flight data revealed that as the aircraft reached an altitude of 400 feet AGL, the battery current dropped significantly. This drop in current led to a loss of communication between the aircraft and the controller. Further examination of the battery cells showed a voltage drop between two and three minutes into the flight, accompanied by a hardware warning indicating a faulty battery.
Findings
- The primary cause of the incident was a hardware failure involving the battery during flight.
- A contributing factor was that the battery had exceeded the 250-cycle lifespan recommended by the manufacturer.
- The loss of power caused the C2Link communication to fail, preventing the return-to-launch sequence from completing.