CTR, TMA, RMZ, TMZ and ATZ

Alongside the airspace classes there are areas with their own names and their own obligations. They are not an additional class but an additional requirement inside a class – which is exactly why they are so often overlooked.

Applicability: Germany (airspace of the Federal Republic of Germany)
Rulemaking authority: Aeronautical Information Publication Germany – AIP VFR (DFS Deutsche Flugsicherung GmbH), effective 20 AUG 2026, ENR 1-1, ENR 1-19 and ENR 1-20
Reviewed by NorthTrack on: 2026-09-13

The terms at a glance

Areas with a name of their own

In most cases the English expansion explains the obligation by itself: "Radio Mandatory Zone" and "Transponder Mandatory Zone" say what is required.

CTR — Control zone
In Germany, class D airspace from the surface around aerodromes with an air traffic control unit.
TMA — Terminal Control Area
Concentrates arrival and departure routes; designated class C or D in Germany.
CTA — Control area
Controlled airspace from a defined height above the ground upwards.
RMZ — Radio Mandatory Zone
An initial call before entry, a continuous listening watch, and a call on leaving.
TMZ — Transponder Mandatory Zone
The code and the monitoring frequency are given on the ICAO 1:500,000 aeronautical chart.
ATZ — Aerodrome Traffic Zone
To be avoided when no landing is intended; entry and exit only with permission.
TRA — Temporary Reserved Airspace
Active for limited periods; the current state comes from NOTAM.
R … — Restricted area (followed by identification)
Designated ED-R in Germany.
D … — Danger area (followed by identification)
Marked as such on the chart.
HX — Not permanently active, no specific working hours
The current state can only be established from a NOTAM or by asking.

CTR – the control zone

The control zone protects the arrival and departure area of an aerodrome with an air traffic control unit from the surface upwards. In Germany it is designated as airspace D (CTR). A clearance, a continuous listening watch and the two additional weather conditions ground visibility 5 km and ceiling 1,500 ft all apply – details on the airspace classes page.

TMA – the terminal control area

The terminal control area sits above the control zone and gathers the arrival and departure paths. In the German structure it appears as C or D, often stepped with a cross-section that widens with altitude. For VFR that mainly means: clearance required, listening watch required – or you plan below it, or around it.

RMZ – radio mandatory zone

The AIP sets the procedure out expressly (ENR 1-20). Before entering, an initial call on the designated frequency is required, containing:

the designation of the station being called
the callsign and aircraft type
position, flight altitude and intentions

While flying in the RMZ a continuous listening watch is to be maintained, and leaving the zone is to be reported as well.

If nobody answers
If the ground station being called does not reply, the flight through the RMZ may nevertheless be continued, provided the listening watch is maintained. The radio calls are to be made even when no reply is received. (AIP VFR ENR 1-20.)

Local exemptions – for example for VFR aerodromes or air sports sites lying inside an RMZ – may be laid down by the competent aviation authorities of the Länder. The areas are depicted on the ICAO chart 1:500,000.

TMZ – transponder mandatory zone

In a TMZ there is an obligation to operate the transponder. The airspace structure diagram gives code 7000 for powered VFR flights and, as typical reference altitudes, 5,000 ft AMSL or 3,500 ft AGL (ENR 1-1). What governs is always the depiction of the specific area: per ENR 1-19, all TMZ are shown on the ICAO chart 1:500,000 together with the applicable transponder code and the associated monitoring frequency.

TMZ with a listening squawk
For a number of German TMZ, a listening watch on a monitoring frequency is required in addition to the code. Which areas those are, and which codes and frequencies apply, is listed in the AIP under ENR 1-19. That list changes – it belongs in flight preparation, not in memory.

If the crew is on a flight information service frequency before entering the TMZ, the AIP provides for reporting that the FIS frequency is being left, changing the transponder code to the one published on the ICAO chart, and maintaining a listening watch on the frequency published there. Where a landing at a controlled aerodrome is intended, the arrangements laid down for that apply instead – that is, establishing radio contact with the aerodrome control unit.

ATZ – aerodrome traffic zone

An ATZ is to be avoided unless a landing within the ATZ is intended. The conditions for entry and exit are laid down for each ATZ; entry and exit require permission. That permission is deemed to have been given where the conditions laid down for the ATZ concerned are complied with. Per ENR 1-20 such an arrangement exists for the aerodromes Essen/Mülheim, Frankfurt-Egelsbach and Magdeburg/Cochstedt.

Restricted, danger and prohibited areas

Independently of the classes there are areas with restrictions of their own. In the German diagram they appear as ED-R (restricted area, in part designated as TRA). Their effectiveness is often limited in time – areas marked HX have no fixed hours of operation. For any particular flight, therefore, what governs is current information from NOTAM and the AIP, not the chart alone.

Airspace is national
ICAO defines classes A to G, but no State is obliged to use all of them, and the way they are applied differs considerably. The figures on this page refer to Germany. For a flight abroad, the Aeronautical Information Publication of the State concerned applies — even where the class letters are the same.

The NorthTrack map view helps you spot these areas along your planned route in good time. Open the NorthTrack App

Official sources

DFS Deutsche Flugsicherung GmbH: Aeronautical Information Publication Germany – AIP VFR – Effective 20 AUG 2026. Open source (retrieved 2026-09-13)
DFS Deutsche Flugsicherung GmbH: Aeronautical Information Publication Germany – AIP VFR, GEN 2-1 to GEN 2-7 "Abkürzungen / Abbreviations" (bilingual German/English) – Effective 20 AUG 2026. Open source (retrieved 2026-09-13)