A man was injured after a drone propeller fell on him in Dublin, according to a report from air accident investigators.
The incident occurred during an urban flight by an unmanned drone delivery company in July 2022.
The Air Accident Investigation Unit released a report into the incident on Friday.
It said a propeller blade became separated from the drone during the flight, causing severe vibrations and the subsequent failure of an electric motor.
This triggered the onboard flight termination system and emergency parachute deployment. The drone struck the ground with minor damage.
Meanwhile, the propeller blade that had separated struck a man on the ground.
The man told the investigation that he was mowing the lawn in his back garden when he was struck by what he believed to be part of a propeller from a drone.
He stated that he did not notice anything unusual prior to being struck due to the noise emitted from his lawn mower.
He said that he sustained a small cut to his head but did not require stitches nor hospital attention.
The investigation determined that the probable cause of the accident was a fatigue fracture of a bolt securing the propeller blade, which caused the blade to separate from the drone.
The drone did not have an airworthiness certification, but was not required to have one.
The remote pilot had not been issued a “Practical Assessment Completion Certificate” until after the accident, the report said.
The drone impacted the ground in a public park and sustained some damage.
The AAIU was not notified of the accident as required.
The propeller manufacturer stated that the polymer propeller as used on the drone should not be used in a coaxial configuration. The company subsequently redesigned the propeller hub.
The company has also committed to changing from the current coaxial configuration to a new design consisting of a single propeller mounted on each arm.
