POLICE lost control of a drone before it crashed into a Poole house and landed on a first floor balcony.

A report by the Air Accident Investigation Branch (AAIB) found if people had been on the balcony they could have been “seriously injured” by the drone’s propeller blades.

Officers from Dorset Police were using the unmanned DJI Matrice 210 aircraft at 400feet during an operation back in November 2020 when wind speeds went above those forecast and in excess of the device’s limit.

The AAIB said shortly after the officers launched the drone one of its two batteries became disconnected, which reduced maximum pitch and maximum speed.

A notice displaying the battery communication message included the words ‘land as soon as possible’ but the officer piloting the drone controls did not notice it.

Bournemouth Echo: The drone flight path in Poole shown in a red line. Picture: AAIB/Google EarthThe drone flight path in Poole shown in a red line. Picture: AAIB/Google Earth

When the wind measured by the drone exceeded manufacturer DJI’s wind limit the alert message to the pilot advised him to ‘fly with caution’ instead of to ‘land as soon as possible’.

The wind was stronger than forecast and at time above the restricted maximum speed of the drone so the pilot could not fly it back towards him.

After communication was lost with the drone, it entered an auto-land mode but it was unable to avoid colliding with the wall of a property in the Park Lane Road area, near the Poole Park boating lake.

The collision damaged the propellor blades before the aircraft came to rest on the balcony.

Bournemouth Echo: The drone was found on a first floor balcony. Picture: AAIBThe drone was found on a first floor balcony. Picture: AAIB

A summary by the AAIB said: “The investigation revealed that shortly after take-off one of the unmanned aircraft’s two batteries had disconnected which resulted in its maximum speed being restricted, but this restriction is not referenced in the user manual and neither the remote pilot nor operator were aware of it.

“When the unmanned aircraft detected that the manufacturer’s wind limit had been exceeded, the message triggered on the pilot’s controller display was ‘Fly with caution, strong wind’ instead of advising the pilot that the limit had been exceeded and that the UA should be landed as soon as possible.

“Three safety recommendations are made to the unmanned aircraft system’s manufacturer and one to the Civil Aviation Authority on visual line of sight guidance.”

Bournemouth Echo: The drone collided with the wall of a house before falling onto a balcony. Picture: AAIBThe drone collided with the wall of a house before falling onto a balcony. Picture: AAIB

Since the incident, Dorset Police retired their DJI Matrice 210 drones and used the newer Matrice M300.

A Dorset Police spokeswoman said the force fully co-operated with the AAIB throughout its investigation.

"The drone was deployed in line with manufacturer regulations at the time. Recording the wind speed and direction is one of our pre-flight checks, which all pilots must complete prior to take-off and where this exceeds the manufacturers recommendations, a drone is not deployed as air safety is a priority," the spokesperson said.

"Since the incident in November 2020, the team has replaced the type of drones used to an updated model.

"The aircraft that is now used has a higher wind resistance capability, as well as being able to give the pilot an accurate wind speed and direction during flight, which the previous generation of drone was unable to do.

"While there were no formal recommendations for the force, a number of learning points were implemented across the alliance, including ensuring that all pilots have up-to- date training and the introduction of a buddy check system."