What happened
On 18 April 2021, a Parrot Anafi USA was conducting a commercial survey of fields and woodland near Princes Risborough, Buckinghamshire. The unmanned aircraft was flying at an altitude of 60 m agl, with an operator controlling the flight and camera while an observer maintained visual line of sight. The weather conditions were characterized by low wind and good visibility despite overcast skies.
After approximately 11 minutes of stable flight, the aircraft was hovering while the operator performed a yaw maneuver to pan the camera. During this maneuver, the controller suddenly lost all connection with the aircraft, and the video feed on the control tablet reverted to white noise. The operator observed the Wi-Fi signal strength indicator drop from green to red, but no further error messages were provided.
The observer witnessed the aircraft pitch forward and enter a rapid descent into a nearby wooded area. The aircraft was later located 300 m from its last known position, resting upside down. The impact resulted in damage to the rotor blade, propeller arms, and the battery locking mechanism.
The investigation
Following the incident, the aircraft was recovered and sent to the manufacturer for a detailed technical examination. The investigation focused on the sudden loss of telemetry and the subsequent uncontrolled descent.
Findings
- The manufacturer determined that an abnormal solder connection likely occurred during the component surface mounting process.
- This faulty connection between the aircraft's printed circuit board (PCB) power circuit and the battery caused the aircraft to lose power mid-flight.
- A subsequent audit of the manufacturer's production processes, equipment, and existing stock—including demonstration units and service returns—revealed no other instances of similar soldering abnormalities.