The Earth
The Solar System & Time
Using Aeronautical Charts
Basics of Navigation
Distance, Speed & Time
Vertical Navigation
Fuel Planning
Practical Navigation Techniques
Radio Navigation
Practice Exam


Controlled Airspace

Controlled airspace on the 1:500 000 aeronautical chart is shown as a solid or dashed line with tinted banding. Along the edge are the airspace class, title, and vertical limits:

The airspace title is written
The airspace class is written inside a coloured box
The airspace vertical limits are written as an altitude AMSL or Flight Levels

The airspace is colour-coded to make the distinction between class A (in which VFR aircraft cannot fly without special permission) and Classes B – E more obvious.

Class A airspace is brown
Classes B, C, D, and E are blue

Aerodrome Traffic Zone (ATZ)

Larger airports and airfields will generally be surrounded by an Aerodrome Traffic Zone (ATZ). The ATZ is marked on the 1:500 000 chart by a ring of brownish-purple dots, with a shaded circular area.

Alongside the ATZ is the elevation of the airfield (its altitude above sea level), the airport ICAO code, and the relevant radio frequency.

Caernarfon ATZ as shown on the 1:500 000 chart. In this case, the airport elevation is 14 feet, the ICAO code is EGCK and the relevant frequency is 122.255

The size of the ATZ depends on the length of the airport’s longest runway:

Runway 1,850m or less, the ATZ has a radius of 2nm
Runway longer than 1,850m, the ATZ has a radius of 2.5nm

The ATZ extends vertically 2,000ft above the aerodrome elevation. So if the aerodrome is 230ft above mean sea level (AMSL), the ATZ extends up to 2,230ft AMSL.

Some ATZs may not be circular in shape due to the surrounding airspace.

Military Aerodrome Traffic Zone (MATZ)

A MATZ is an area of military airspace that has 2 sections:

A circle around the aerodrome with a radius of 5nm and a vertical extent of 3,000ft above the aerodrome
Two stubs that are 4nm wide and extend 5nm out from the centre circle. The stubs extend vertically from 1,000ft to 3,000ft above aerodrome level.

The two stubs are aligned with the aerodrome’s main runway.

A MATZ is marked on the 1:500 000 aeronautical charts with a purple dotted outline and purple shading

There is usually a standard ATZ within the MATZ. Strictly speaking, there is no legal requirement for civilian pilots to contact the military aerodrome before flying through a MATZ but it is strongly advised that you do – the military is often flying very fast and hard to see aircraft!

You are required to contact them before passing through the ATZ, just like any other ATZ!

Not all MATZ conform to this standard shape and sometimes two or more MATZ are combined.

TMZs and RMZs

Transponder Mandatory Zones (TMZs) are areas in which it is mandatory to have a functioning transponder that is transmitting both your position and altitude before entering.

TMZs are marked on the chart by brown half-circles.

Radio Mandatory Zones (RMZs) are areas in which it is mandatory to establish radio contact with the relevant Air Traffic Service Unit (ATSU) before entering.

RMZs are marked on the chart by blue half-circles.