A drone near an airport can stop flight operations within minutes. A recent incident at Brussels Airport shows how much disruption one unauthorised drone can cause — and why stopping it safely is not always simple.
On 11 September, flights at Brussels Airport were temporarily suspended after a drone was reported nearby. Skeyes, the Belgian air navigation service provider, activated its drone procedures. Runway operations stopped for 30 minutes after the last sighting.
There was no reported collision. However, airports must take drone sightings seriously, especially near runways or aircraft.
What happens when a drone is reported?
The first step is to establish what someone has seen and where the drone is.
Reports can come from pilots, air traffic controllers, airport employees or members of the public. Airport teams and air traffic controllers assess the situation and decide whether flight operations need to be restricted.
Depending on the drone’s location, aircraft may have to hold, departures may be delayed, or runway operations may stop temporarily.
At Brussels, runway traffic stops for a set period after the last sighting. During this time, Skeyes and air traffic control check whether it is safe to resume flights. This procedure applies even if the drone is seen only briefly.
How do airports detect drones?
Detecting a drone can be difficult. Aircraft, vehicles, birds and other objects move around the airfield and the surrounding airspace.
Airports can use radar, radio-frequency sensors and cameras to detect and track drones. Radio-frequency sensors detect radio signals from drones. Together, these systems help teams establish the drone’s position and check whether it is still in the area.
Prevention is also important. Most UK airports have a Flight Restriction Zone (FRZ), where drone operators need permission to fly.
The zone usually extends several kilometres around the airport. Additional protection around runways can extend up to 5 km from the runway ends and reach 2,000 ft above the ground.
Operators who break these rules may face fines, lose their registration or certificate for a period of time, or even go to prison.
Why is it difficult to stop a drone safely?
UK Airprox Board reports for 2025 recorded at least seven drone encounters involving aircraft around Heathrow. In several cases, pilots reported that a drone passed within 100 ft of their aircraft.
However, detecting a drone does not mean that authorities can safely bring it down. If they disable it, it could fall onto a runway, hit an aircraft or land in an area where people live.
Counter-drone systems are equipment used to detect or stop drones. Some of these systems can also affect other equipment, so they must be used carefully.
Airport teams therefore have to protect aircraft without creating another safety problem.
Not every drone sighting is an attack. An operator may enter restricted airspace by mistake or may not understand the risks. Whatever the reason, the airport’s immediate priority is to keep aircraft and passengers safe.
How much disruption can one drone cause?
A drone does not need to collide with an aircraft to cause serious disruption. The possibility of a collision can be enough to stop flights.
A single sighting may cause aircraft to hold or divert while airport teams and air traffic controllers check whether operations can continue safely.
At a major airport, delays can quickly affect flight schedules, aircraft movements and passengers. The cost in time and money can be high. The Brussels incident shows how a small unmanned aircraft can create a much larger operational problem.
What will airports need in the future?
As drones become easier to obtain and more capable, airports will need to improve how they detect and respond to unauthorised flights.
The main challenge is to identify a genuine threat, respond quickly and resume normal operations once the airspace is safe.