How Well Do You Know Aerodrome Traffic Zone Procedures?
An article produced by CAA DAP in December 2012.
Pilots will be very familiar with the term ‘aerodrome traffic zone’ (ATZ). In fact the term is familiar all around the world courtesy of ICAO’s definition of an ATZ as "an airspace of defined dimensions established around an aerodrome for the protection of aerodrome traffic.” What may not be immediately apparent is that, unlike many other countries, the UK has taken the basic concept of an ATZ further than ICAO and fixed the dimensions associated with these.
The legal basis for ATZs as established in the UK is Article 258 of the Air Navigation Order. Essentially, subject to runway length ATZs will have a lateral boundary of either a 2 or 2½nm radius centred upon the mid-point of the longest runway. In all cases ATZs extend vertically from the surface to a height of 2000ft above the level of the aerodrome. So remember, the upper limit of an ATZ will vary in amsl terms. Laterally, ATZs may not overlap, meaning that a number of adjacent ATZs have abutting boundaries. ATZs will assume the background classification of the airspace in which they are established. In practice, most ATZs are encountered in Class G airspace but airfields within Control Zones will also have an ATZ. For details of ATZs at licensed aerodromes check out individual aerodrome entries the AIP AD-2 section; details of ATZs at unlicensed and Government aerodromes are at ENR 2.2 (the online version of the AIP can be found at http://www.nats-uk.eadit.com/public/index.php.html).
Not only are the boundaries of an ATZ defined in the UK, there are also established requirements to be met when flying in any one of the 150+ ATZs that currently exist.
These requirements are set out at Rule 45 of the Rules of the Air Regulations 2007 and are repeated in the UK AIP. Why are they needed? Well, the aim of an ATZ is to provide a degree of protection to traffic in the immediate vicinity of an aerodrome. That said, ATZs are not established with the aim of providing segregation between various (and potentially disparate) operations but with the goal of enhancing the safe integration of these in the immediate vicinity of an aerodrome.
Rule 45 Requirements
Every year a number of ATZs are infringed by pilots. Some of the affected airfields provide air traffic control (ATC) services, some provide Aerodrome Flight Information Service (AFIS), while others have Air-Ground (A/G) facilities. Individual AIP AD2 entries will tell pilots what level of air traffic service is available at each airfield, and this information also appears in commercial VFR guides. While ‘TWR’, ‘AFIS’ and ‘A/G’ indications are provided on VFR chart Frequency Reference Cards, the VFR charts themselves don’t provide any such clues.
As part of their pre-flight planning it’s essential that pilots understand the communications requirements associated with any ATZs that may be crossed along their intended route. It’s equally essential that contact is established with the controlling authorities of affected ATZs before entering them. This is a requirement of Rule 45 – so the pilot of an aircraft crossing an ATZ without establishing this contact is in breach of the Rules of the Air.
To dispense with any of the ‘myths and legends’ associated with operating in an ATZ that seem to exist, it’s essential that the fundamentals of Rule 45 are readily understood. These can be summarised as follows:

During the notified times of ATZ activation:
 Pilots are required to establish and maintain RT contact with the appropriate ATC, AFIS or A/G communications unit before operating within an ATZ and throughout the period of operations within it.
 Where the ATZ is served by an ATC unit, operations within it are subject to the permission of the ATC unit. In other words a clearance to enter the ATZ must be obtained before entering it.
 Where the ATZ is served by AFIS or A/G only the pilot must obtain information from the FISO or A/G Operator such that he/she can ensure that that the flight within the ATZ can be conducted safely.
In a nutshell, and subject to certain conditions that might facilitate non-RT operations, a pilot wishing to fly within an ATZ needs to establish and maintain 2-way communications with the relevant ATC, AFIS or A/G communications unit prior to entering an ATZ.
A Common Myth
Some pilots seem to believe that if they call three times on the assigned frequency and don’t establish two-way contact as required by Rule 45, then it is OK to enter the ATZ. Or is it?
NO IT ISN’T! Any suggestion that upon receiving no reply to any number of calls on the appropriate frequency a pilot may operate within an ATZ that is notified as being active is incorrect and contrary to the provisions of Rule 45. Put simply, if for whatever reason you are unable to establish 2-way communications with the aerodrome during its notified ATZ hours you cannot comply with Rule 45 and therefore should avoid the ATZ.
Outside the notified hours of any ATZ the requirements of Rule 45 do not apply. However, given that it is quite possible that the aerodrome might still be active beyond the ATZ notified hours, it remains a sensible option to call on the published frequency to establish what activity is taking place.
Military Air Traffic Zones (MATZs) and their ATZs
Pilots need to be mindful that military airfields that have a MATZ around it will also have an ATZ. When crossing a MATZ it is a pilot’s responsibility to ensure that permission is also obtained to transit the ATZ – Rule 45’s requirements apply here too. Good Airmanship
Good Airmanship
As ever, thorough pre-flight planning is essential and checking aerodrome and airspace times is a key part of preparation. Check the AIP and NOTAMS. Know the rules and requirements for each, remain aware that notified ATZ hours may not be the same as notified aerodrome opening hours, and that aerodromes can be active outside notified opening hours.
Any ATZ Queries?
If you have any queries concerning ATZ policy and operations within them, these should in the first instance be addressed to Directorate of Airspace Policy by e-mail to ora@caa.co.uk, or by phoning 0207 453 6545.