Delivery, Ground, Tower, Approach, Center: who handles what on the radio

At the spot you see only a snippet: an A320 taxis to the runway, waits, takes off, turns away. In the background, though, this flight has already passed through several hands in those few minutes – and will do so several more times on its way to the destination. Delivery, Ground, Tower, Approach and Center are not synonyms for “air traffic control” but clearly separate positions with their own airspace, their own frequency and their own authority. This guide shows you who is responsible for what, where the handoffs are and how it is organized in Germany.

The short answer

Air traffic control is divided by airspace. Delivery issues the route clearance at the gate. Ground (taxi control) regulates the taxiways. The Tower (aerodrome control) is master of the runways and the control zone right at the airport and, as the only position, issues takeoff and landing clearances. Approach and Departure (arrival and departure control) guide traffic by radar in the wider area around the airport. The Center (area control) takes over the en route flight between airports.

Each position works on its own frequency. A flight is only ever “under control” of one of them and is sent to the next with a clear instruction at the boundary. On landing, the chain runs in reverse.

All positions at a glance

Position	German term	Responsible for	Typical instructions	Location
ATIS	Automatische Ausstrahlung (automatic broadcast)	Weather, runway, air pressure as a continuous loop	none – information only	–
Delivery	Streckenfreigabe (route clearance)	Clearing the route before taxiing	Departure route, initial altitude, transponder code	Tower
Apron	Vorfeldkontrolle (apron control)	Positions and taxi lanes on the apron	Pushback, taxi instructions until handoff	Tower or separate apron tower
Ground	Rollkontrolle (ground control)	Taxiways and intersections on the maneuvering area	Taxi routes, holding before intersections	Tower
Tower	Platzkontrolle (aerodrome control)	Active runways and control zone	Line up, takeoff and landing clearance, go-around	Tower
Approach / Departure	An- und Abflugkontrolle (arrival and departure control)	Airspace around the airport	Headings, altitudes, speeds, sequence	mostly control center
Center	Bezirkskontrolle (area control, ACC)	En route flight, divided into sectors	Climbing, descending, direct routes, diversions	control center

The “Location” column shows a point that surprises many: only the positions that need to see the field directly sit in the tower. Approach and Center work with radar and flight plan data and don’t need a view out of the window.

Delivery: the clearance before the first meter

Before an airliner moves, the crew first picks up the current ATIS information – weather, active runway, air pressure, identifier letter. What is announced there is explained in the post ATIS explained. Then they contact Delivery.

Delivery issues the route clearance: the destination, the departure route (SID), the first cleared altitude and the transponder code that the crew sets. The crew reads the clearance back word for word; only when Delivery confirms it does it apply. What the departure routes are about is in SIDs and STARs, and the code part is explained in Transponder Mode A, C and S.

Delivery is also an important switching point for delays: if a flight has been given a time slot because of capacity bottlenecks in the airspace, it is taken into account here – better an aircraft waits at the gate with engines off than at the runway with engines running. The European traffic flow management behind this is described in the article on Eurocontrol.

At large airports the crew can also request the clearance via data link and then receives it as a text message in the cockpit. At smaller fields there is often no separate Delivery frequency; then Ground or the Tower handles the clearance as well.

Apron and Ground: everything that taxis

On the ground in Germany, depending on the airport, two positions share the work.

The apron – that is, the parking positions and the taxi lanes between them – is controlled at the airports Frankfurt, Munich, Hamburg, Dresden and Erfurt by a separate apron control of the airport operator. Its call sign is “Vorfeld,” internationally “Apron.” It approves pushback and engine start, assigns taxi routes on the apron and coordinates tugs, follow-me vehicles and marshallers. Because ground vehicles also operate on the apron and distances are smaller than on the maneuvering area, it formally issues instructions instead of clearances – for the crew they are binding all the same. What this workplace looks like is shown in the post Apron control, and the procedure at the gate is explained in Pushback.

Ground, the air traffic control taxi control, takes over on the taxiways of the maneuvering area. It sets the route to the runway, has aircraft wait at intersections, sorts departures into a sensible sequence and guides landed aircraft back toward the apron. At airports without their own apron control, its area extends to the parking position.

Exactly where one position ends and the other begins is in the aerodrome charts of the Aeronautical Information Publication. How to read such a chart is explained in Reading AIP aerodrome charts.

Tower: master of the runway and control zone

The Tower – in German, Platzkontrolle (aerodrome control) – is the position that sounds most familiar on the radio, and rightly so. Only here is it decided who may enter the runway. The most important powers:

• Line up and wait: “Line up and wait” allows an aircraft to taxi onto the runway but not yet to take off.
• Takeoff clearance: “Cleared for takeoff” is given only when the runway is clear and the distance to the traffic ahead is right.
• Landing clearance: “Cleared to land” is also issued exclusively by the Tower.
• Go-around: If the runway is not clear in time, the Tower sends an approaching aircraft around. What happens then is explained in Go-around explained.
• Runway crossings: Even taxiing aircraft that have to cross an active runway need a Tower clearance.

Besides the runway, the Tower is responsible for the control zone (CTR), the airspace directly around the airport. This mainly concerns VFR pilots who want to pass through the zone or land at the field. Which airspaces exist and who may do what in them is explained in Airspace classes A to G.

Large airports with several runways often split the tower: each runway system can have its own Tower frequency so that takeoffs and landings don’t block one another. At Frankfurt Airport with its parallel runways and the separate west runway, or at Munich Airport with two independently operated runways, this is easy to see.

The tower doesn’t have to stand at the airport

Classically, controllers look through the glass cab at the field. Since December 2018, however, the DFS has controlled Saarbrücken Airport from a Remote Tower Center at Leipzig/Halle Airport, about 450 kilometers away; Erfurt-Weimar was added later. Cameras and sensors supply the picture there that the window would otherwise show. Nothing changes for the crew: they still call “Saarbrücken Tower.”

Approach and Departure: the area around the airport

Shortly after liftoff, the Tower sends the departure on to Departure. This position guides it out of the dense traffic around the airport, clears the climb and hands it to area control.

For landings, Approach (approach control) is the decisive position. Approach takes over aircraft from the route network, sequences them for approach, assigns headings, altitudes and speeds and thus builds the chain on final approach. Once the aircraft is stable on the landing course, it goes to the Tower. How the instrument approach itself works is explained in The ILS approach; that wake turbulence also plays a role in the sequence is shown in Wake turbulence separation.

At large airports this work is spread over several positions: one for inbound flights into the area, one for fine-tuning on final approach, which depending on the country and airport may also be called “Director” or “Arrival.” When it gets busy, approach control sends aircraft into holding patterns – more in Holding explained.

In Germany, arrival and departure control at the large airports does not sit in the tower but works by radar. For the 15 international commercial airports, the DFS provides these services.

Center: the en route flight

From a certain distance from the airport, area control takes over, internationally the Area Control Centre (ACC). It is responsible for traffic between airports: climb to cruising altitude, direct routes, diversions around thunderstorms, descent toward the destination. Its airspace is divided into sectors, horizontally and by altitude. With every sector change the flight changes frequency – several times on a domestic flight.

In Germany, the DFS operates control centers for this in Langen, Bremen and Munich for the lower airspace and in Karlsruhe for the upper airspace. Over parts of northern and western Germany, the Eurocontrol center in Maastricht controls civil traffic in the upper airspace. Who is behind German air traffic control is explained in the post DFS German Air Navigation Service Provider, and the neighbors are introduced in Austro Control and Skyguide.

Call signs: how to recognize the position

On the radio, every position states its call sign: usually place name plus service. That is how crews address “Munich Tower,” “Hamburg Ground” or “Frankfurt Delivery.” For area control, countries differ considerably:

Country / organization	Area control calls itself	Example
Germany (DFS)	Place name plus “Radar”	“Langen Radar,” “Bremen Radar”
Germany, upper airspace Karlsruhe	Region name plus “Radar”	“Rhein Radar”
Eurocontrol Maastricht	Place name plus “Radar”	“Maastricht Radar”
United Kingdom	Place name plus “Control”	“London Control”
USA	Place name plus “Center”	“New York Center”

That is where the “Center” in this article’s title comes from: it is the American call sign that has become established among spotters as a collective term for area control. For airfields without air traffic control, Germany has designations of its own: “Radio” for the flight information at uncontrolled fields, “Information” for the flight information service. How sentences are built on the radio is explained in Radio phraseology, and which language applies is in English or German on aviation radio.

A flight from gate to gate

This is what the chain looks like for a typical scheduled flight. Depending on traffic, frequencies are combined – at night at some fields one person sits at several positions at once.

Every handoff follows the same pattern: the handing-off position names the next one and its frequency, the crew reads back, switches and checks in with the new position using its callsign. Why the callsign does not always match the flight number is explained in Callsign vs. flight number. Which frequency ranges are behind this is shown in Understanding aviation radio frequencies.

What this knowledge gives you at the spot

You don’t need to listen to the radio to benefit from these responsibilities. A few practical effects:

• Reading live maps: The string of pearls on final approach is the work of approach control. When aircraft far out fly arcs or circle, Approach is sorting the traffic – your target aircraft then arrives later. How to recognize holding patterns on the radar is shown in Spotting holding patterns on flight radar. When it is especially busy at hubs is explained in Understanding hub waves.
• Understanding the runway direction in use: Which runway is active is determined by air traffic control based on wind and traffic and broadcast via ATIS. The guide Understanding the runway direction in use at an airport shows how to estimate it in advance.
• Putting waiting times in context: If an aircraft stands at the gate or the holding point for a long time, there is often a time slot or the sequence at the runway behind it.
• Understanding videos: In recordings on video platforms you hear the handoffs – with this article you know who is speaking. What applies legally when publishing radio in videos is in Publishing aviation radio in videos.

At spots like the Zeppelinheim viewing platform or the Munich Airport visitors’ hill (Besucherhügel), you see the work of Ground and Tower especially well: taxi traffic, lining up, takeoffs and landings play out right in front of you. More locations are shown in the guides to Frankfurt and Munich.

What to keep in mind

• Don’t mix up terms: “The Tower diverted him” is almost always wrong – heading changes in the air come from Approach or Center.
• Not every airport has all positions: At small fields, one frequency handles Delivery, Ground and Tower together.
• Names vary: Whether the fine-tuning on approach is called “Director,” “Arrival” or simply “Radar” is decided by each country and sometimes each airport itself.
• Frequencies change: The Aeronautical Information Publication is authoritative, not an old list on the web. A starting point for chart material is openAIP.
• Go deeper: How the work of these positions came about over decades is told in the history of air traffic control; anyone who wants to get into it themselves can read Becoming an air traffic controller.

Conclusion

Air traffic control is a relay race with clear handoffs. Delivery clears the route, Apron and Ground bring the aircraft to the runway, the Tower decides on takeoff and landing, Approach and Departure sequence the traffic around the airport, and the Center guides the en route flight. In Germany this lies in the hands of the DFS at the large airports, with the apron at five airports run by the operator itself. Anyone who knows this chain reads live maps with different eyes.