What happened
On July 2, 2021, at approximately 13:58 local time, an Aero41 SA (AGv2-16) unmanned aircraft was conducting a commercial work flight in Meilen, Canton of Zurich. The operation was being conducted under Visual Line of Sight (VLOS) rules. During the flight, the drone began performing autonomous maneuvers that were neither intended by the remote pilot nor controllable via the ground station. This uncontrolled flight, commonly referred to as a fly-away, caused the aircraft to deviate from its planned path and collide with a tree, which subsequently led to the drone crashing.
The investigation
The Swiss Transportation Safety Investigation Board (SUST) examined the circumstances surrounding the loss of control of the aircraft. The investigation focused on the sequence of events leading from the start of the uncommanded maneuvers to the impact with the vegetation. The investigation confirmed that the drone was operated by a single remote pilot and that the flight was part of a professional work mission.
Findings
- The primary cause of the accident was a fly-away event characterized by autonomous maneuvers that the remote pilot could not intercept or correct.
- The impact with a tree resulted in heavy damage to the Aero41 SA.
- There were no injuries to third parties or the operator during the incident.