No Fly Zones
Every cubic centimetre of sky above the UK is within a block of airspace that has a formal designation, and for which there are rules that govern who or what can fly in it and under what circumstances.
ICAO airspace classification
The UK uses the system of international airspace classification developed by the International Civil Aviation Organisation (ICAO) whereby the status of a piece of airspace is denoted by a letter that is shown on all aeronautical charts. It is this letter that determines the rules applying to it. Airspace Classes A, B, C, D and E are all forms of controlled airspace, while airspace Classes F and G are uncontrolled.
Controlled airspace comes in various shapes and sizes: aeronautical charts depict the horizontal boundaries accurately and state the vertical dimensions.
ANO Article 166 places restrictions on the operators of SUAs weighing more than 7kg. This prevents them operating in airspace Classes A, C, D and E, and also prevents them operating within an active aerodrome traffic zone (without ATC permission). There are no such restrictions on SUAs weighing less than 7kg – except that you must be reasonable satisfied that the flight can be safely made. (But be aware that even sub 7kg SUAs are subject to the laws governing Danger Areas, Restricted Areas and Prohibited Areas – so may only be operated in these locations if and when permitted.)
Other types of airspace
Even within ‘uncontrolled’ Class G airspace there are various non-ICAO types of airspace that have entry restrictions or requirements, some of which are described below.
Aerodrome Traffic Zone (ATZ)
Aerodromes with an ATZ have it shown on the charts, except where they are already inside controlled airspace (in which case they still have one but it is not shown). An ATZ consists of the airspace from the surface to a height of 2000 ft above the level of the aerodrome, bounded by a circle of either 2 nautical miles or 2.5 nautical miles radius, depending on the length of the main runway. (The horizontal dimensions are drawn accurately on the aeronautical chart.) The aerodrome’s altitude is printed alongside the symbol.
SUAs weighing less than 7kg can be flown within active ATZs – but the pilot would need to be confident that the flight can be safely made – which would be impossible unless the drone pilot had a full understanding and knowledge of aircraft procedures at the aerodrome and a full safety briefing with all parties involved.
Lots of airfields are ‘unlicensed’ and so do not have an ATZ. They are shown on the charts with just a small location symbol. These can also be very busy places with lots of aircraft movements. It would be extremely foolish / reckless to operate model aircraft/ drones at or near to such an airfield when aircraft are operating, except within an agreed safe area.
Military Aerodrome Traffic Zone (MATZ)
These typically consist of the airspace from the surface to a height of 3000 ft above the aerodrome’s altitude (which is printed alongside the symbol, as with ATZs), bounded by a circle of radius 5 nautical miles from the aerodrome’s reference point – plus a projecting stub aligned with the principal runway 5 nautical miles long and 4 nautical miles wide – between 1000 ft and 3000 ft above the aerodrome’s altitude. They look like a pan with a very oversized handle; indeed, the stub is sometimes called the pan-handle. Some MATZs have no stub, or have two or more stubs, or form part of a combined MATZ (CMATZ). Again, the aeronautical charts clearly show their horizontal dimensions.
Every MATZ contains an ATZ, and a MATZ is usually a very busy bit of sky, especially midweek.
Temporary controlled airspace (CAS-T) is established for short periods of time (usually a matter of hours) to protect flights in fixed wing aircraft by some Royal family members and V.V.I.P’s, whenever they operate outside of existing Class A / C airspace.
A Royal Low Level Corridor (RLLC) is established for Royal helicopter flights.
Information on Royal Flights is available daily on Freephone 0500 3548021 and on the Web at www.ais.org.uk.
A Danger Area is exactly that: an area where there is an activity that is dangerous to aircraft. Not all of them have by-laws prohibiting entry – but they are all best left well alone unless you are certain that they are inactive. They usually extend from the surface upwards. On the charts they are identified with a ‘D’ number, e.g. D306/5. The first part is the serial number of the Danger Area, and the final figure (or figures) is the altitude in thousands of feet that it goes up to. The charts also differentiate between those Danger Areas that have published hours of activity (which may be varied by NOTAM) and those that are only activated by NOTAM.
Prohibited and Restricted Areas
As with Danger Areas, the number on the chart after the ‘P’ or ‘R’ number indicates the altitude to which the area extends, usually from the surface. The names Prohibited and Restricted are self-explanatory, referring to areas that are established to protect places or activities that are potentially very hazardous or have security implications. Prohibited areas are exactly that: details of the rules governing specific Restricted Areas can be found in En-Route 5.1, a section of the AIP (Go to the IAIP tab, then ‘Enroute Information – ENR Index’ and then scroll down to ‘ENR 5.1’.) In the absence of accurate information to the contrary, all Restricted Areas should be avoided. Temporary Restricted Airspace (RA[T]) is set up from time to time, and this is notified on Freefone 0500 354802 and on the Web at www.ais.org.uk daily).
High Intensity Radio Transmission Areas (HIRTAs)
Again this is self-explanatory: these sites are likely to be on private MOD land with restricted access – but the transmissions are highly likely to disrupt your R/C link so you may want to keep away in any case.
These include a variety of things, including areas where free-fall parachuting takes place.
On the ICAO chart you will see a lot of other symbols. Obviously navigation aids such as TACANs, NDBs, VORs and DMEs do not matter to us, but you should not operate close to non-ATZ airfields, microlight, gliding and parascending sites unless you have permission.
The information in this chapter is a brief synopsis of the airspace rules as they affect drones / SUA pilots, and is believed to be accurate at the time of writing. In case of doubt, the authoritative primary sources should be consulted. These are:
- the Air Navigation Order
- the Rules of the Air Regulations
- the UK Aeronautical Information Publication.