What happened
On 31 January 2022, a DJI Mavic 2 drone, registered as ZT-UWB, departed from the Sun City Helipad in the North West Province for a surveying mission over the local mountainous terrain. The flight was being conducted under Part 101 regulations during clear weather conditions.
During the initial climb to an assigned altitude of approximately 426 feet, the pilot received a notification on her mobile device. To avoid distraction, the pilot used the controller to pause the flight and walked to a nearby vehicle to attend to the message. Upon returning and resuming the flight, the pilot noticed the aircraft was no longer following its intended path. Shortly thereafter, the drone lost connection with the controller and visual contact was lost. Despite attempts to use the return-to-home function and search for a better signal, the aircraft could not be located and is presumed to have crashed.
The investigation
An internal investigation by the operator's safety manager included an analysis of the flight logs (Pixhawk T-Log). The data revealed that the drone successfully navigated past the first peak but experienced a brief connection loss of 2.6 seconds before a subsequent, permanent loss of connection occurred.
The investigation confirmed that the pilot held a valid Remote Pilot Licence (RPL) and the aircraft had undergone a mandatory periodic inspection earlier that month. However, several operational discrepancies were identified during the review of the mission parameters.
Findings
- The pilot had inadvertently used the incorrect waypoint file for the intended mission.
- The collision avoidance system on the aircraft was deactivated at the time of the flight.
- The flight altitude of 130 meters (approximately 426 feet) was lower than the 150-meter (500 feet) height of the local terrain peaks.
- The loss of control and subsequent crash were linked to the aircraft following an erroneous flight path.