Police DJI M300 Drone Fell 380 Feet After Arm Failed to Lock; UK Investigators Cite Checklist Gap

The UK's Air Accidents Investigation Branch (AAIB) published a report on November 12 on a crash on June 1, 2026 in West Bridgford, Nottinghamshire, England. A police DJI M300 drone lost control after its rear right motor arm folded in flight and fell from about 115 meters (380 feet) onto a residential road. Nobody was hurt. The case matters because the AAIB says the 7.2 kg aircraft could likely have killed a person it hit, and the board has investigated similar M300 crashes before.

A warning nine seconds before the fall

Four minutes and four seconds into the flight, with the drone 355 meters from the pilot, the controller told him to land and check the arm sleeves. Nine seconds later a propulsion system error appeared and the aircraft began spinning and dropping. The crash happened at 03:23 UTC, or 4:23 a.m. local time. The pilot saw very few vehicles and no pedestrians nearby. A police team was searching for suspects and had first flown an Autel MAX 4N for 19 minutes, then switched to the M300 to stream live video because the Autel's stream was less reliable. Wreckage spread over about 20 meters and the batteries landed on the footpath. No property damage was reported, and the drone was damaged beyond economic repair.

Three of the four locking collars were still engaged. The rear right one had come off its thread, and part of the thread had broken away. DJI concluded the M4 arm, the rear right one, had not been properly installed.

The checklist did not cover the arms

The force's pre-flight checklist did not include checking that the arms were locked. The 25-year-old pilot, who had 128 flying hours including 84 on the M300, had set the arms at the start of his shift and said he made a visual check before takeoff. He had not signed off the checklist, and his body-worn camera was switched on only after takeoff. On June 24 the force issued a safety notice requiring pilots to check before every flight that collar marks align and the collar clicks shut.

The National Police Chiefs' Council (NPCC) sent a notice based on it to other forces flying the M300. The bulletin does not name the force involved.

Similar crashes in 2021

The AAIB cites three 2021 M300 crashes in Manchester, Gloucestershire and Chester, where loss of control was attributed to arms not fully secured. DJI later added arm lock detection on its M350 and M400 models.