AAIB investigation to Parrot Anafi (UAS, registration N/A) 170720
Propeller failure, Green Lane, Yeadon, West Yorkshire, 17 July 2020.
Summary:
The operator was conducting a night search of roof tops. About 15 minutes after takeoff, when the UA was at about 50 agl, the pilot noticed the control screen flicker and heard the speed of the UA’s motors increase without any input from him. The UA then started to turn and, despite inputs from the pilot, was unresponsive. He attempted to descend the UA to conduct an emergency landing and then selected the ‘Return to Home’ function, but it did not respond. The UA then entered an uncontrolled descent onto the roof, where it came to rest.
The UA was recovered with damage to its two front left propellers and battery. There was also minor damage to the roof covering.
The pilot believed that, given the clean fractures on the propellers and the way the motors reacted, the UA had suffered a failure of the two propellers.
The AAIB published another reported failure of propellers on a Parrot Anafi in its 9/2020 Bulletin.
Safety actions
Previously the operator would only replace damaged propellers but, as a result of the safety action taken in the published event, they will now also change the propellers every 5 hours flight time. They will also make a video recording of all pre- and post-flight safety checks.
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