A drone carrying out an aerial survey over a construction site in the Cheetham Hill area of Manchester struck the top of a tower crane and fell about 120 m to the ground, according to the latest bulletin from the Air Accidents Investigation Branch (AAIB).
The incident happened in August. It was notified to the AAIB, but no formal investigation was opened, and neither the site nor the contractor involved was identified.
What the bulletin records
According to the AAIB, the unmanned aircraft was flying a pre-selected flight path over a construction site in an urban area. The obstacle avoidance feature was enabled at the time, yet the aircraft still hit the top of the crane and dropped roughly 120 m.
The account draws on an internal investigation by the construction company, which concluded that the company and its remote pilots might not have fully understood the limitations of the obstacle avoidance software.
Points to note
- The flight followed a pre-programmed route rather than being flown manually.
- Obstacle avoidance was active but did not prevent the collision with the crane.
- No formal AAIB investigation was launched and the parties involved were not named.
For operators, the bulletin points to a practical issue: a planned survey route over an urban site can pass close to tall structures such as cranes, and in this case the automated safety feature did not stop the aircraft from striking one. The AAIB bulletin gives no further detail on the outcome of the flight beyond the collision and the fall.