Controlled Airspace

As a drone pilot you must adhere to all airspace rules and regulations as laid out by the CAA and international law but one area of drone flights that often cause some confusion are those large, red areas around aerodromes. These are the CTR's (Controlled Traffic Regions) and FRZ's (Flight Restriction Zones). Let's look at both of these.

Flight Restriction Zone (FRZ)

An FRZ is heavily restricted airspace and your drone will probably not even allow you to fly into this zone. That said, an FRZ is not necessarily a no-go area for drone pilots. It may be possible to fly inside an FRZ by requesting permission from ATC for that area.

The image above shows Bournemouth Airport. The outermost area is the CTR. Moving inward, to the circle with the protruding lines is the FRZ, and the airport is right at the centre of that circle. As a drone pilot you can fly within the outer CTR region (despite Drone Assist showing it as red) but you can't fly into the inner region - the FRZ - without specific permission from ATC.

Controlled Traffic Region (CTR)

Think of the CTR as an area of 3D airspace that surrounds an airport/aerodrome. The CTR is designed to protect aircraft that are entering and leaving the airport. When looking at an aviation chart, the CTR will extend from the surface to (typically) 2,500 feet above ground level and often looks oval in shape, extending out from the inner FRZ (Flight Restriction Zone), and are generally longer at each end, extending out from the runways.

Note: Airspace around aerodromes is generally Class D Airspace. Apps such as the DJI Fly App may show the CTR as Class D Airspace.

Enhanced Warning Zone

An Enhanced Warning Zone around an aerodrome is not the same as a CTR. As discussed above, a CTR is a controlled airspace established around an aerodrome to manage and control air traffic in the vicinity of the aerodrome. An Enhanced Warning Zone on the other hand is typically an advisory airspace designed to provide additional warning and protection to aircraft, but it may not be subject to the same level of control or restrictions as a CTR.

Enhanced Warning Zones are often seen around smaller aerodromes for light aircraft.

In Conclusion

Apps such as Drone Assist show CTR's as red areas suggesting you are unable to fly here. This is not the case. CTR's apply to manned aviation and do not apply drones/unmanned aircraft. As a drone pilot you can fly in a CTR without prior permission but it is extremely important to keep in mind, you are going to encounter more aircraft traffic in these areas. You may also want to consider speaking to ATC before flying within a CTR out of courtesy so they know drones are operating in the area.

More Information

This is a very interesting and clear video explaining this further.