What happened
On the afternoon of 18 June 2023, a DJI Phantom 4 Unmanned Aircraft System (UAS), registered as ZT-UXD, was conducting a training flight near Mooivallei, Potchefstroom. The operation was being carried out under visual line of sight (VLOS) regulations by an approved training organization.
During the flight, while a student pilot was at the controls, the aircraft was flying at an altitude of approximately 8 metres above ground level. Suddenly, a rotor blade detached from the motor hub. This mechanical failure caused the drone to lose both lift and propulsion, resulting in a ground impact. While the aircraft suffered substantial damage, there were no injuries to any persons on the ground.
The investigation
An investigation by the SACAA AIID confirmed that the instructor pilot and student pilot held valid licenses and medical certificates. The operator held all necessary approvals, including a valid UAS Letter of Approval and an Approved Training Organisation certificate. The aircraft's registration was current, and the most recent maintenance inspection had been performed shortly before the incident.
Findings
The investigation established that the primary cause of the incident was the presence of cracks on the propeller blades. These structural defects led to multiple failures of the blades during flight, which directly caused the loss of lift and the subsequent crash.