CyberAirVA

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Air Traffic Control

Air Traffic Control (ATC) is first and foremost responsible for: "promoting the safe, orderly and expeditious flow of air traffic". This tutorial will explain the basics behind the ATC.

ATC is divided into three types of basic facilities, these are Control Towers, Approach Control and Air Route Traffic Control Centers (ARTCC). Within each of these three types there exists several units, these can be:

Clearance Delivery (DEL) This is located in the control center and is often combined with ground control. It issues IFR clearances and general advisories.
Ground Control (GND) Also located in the Control Tower, ground control has control over all the traffic moving around the airports taxiways. It also issues departure information, weather conditions and airport advisories. Ground also maintains a general surveillance of the airport, including inactive runways.
Local Control (TWR) This is the last of the tower controls. The local controller has command of anything that is on the runway(s). It also maintains a surveillance of the airport and the area around it.
Approach Control (APP) Approach control, as the name implies controls the traffic inbound to the airport, it will normally vector you in for an ILS approach and when you are established on the localizer it will hand you over to TWR. At very busy airports approach might be divided into subgroups, i.e. approach east.
Departure Control (DEP) Departure control is also a part of the approach control and handles outbound traffic. Sometimes this might be done by the approach control.
Center Control (CTR) Located in the ARTCC the center offers ATC service to aircraft typically operating with IFR plans during the enroute phase of the flight. The Center might be broken up into smaller pieces, controlling a small piece of the ARTCC.
Flight Service Stations (FSS) These stations do not control the traffic, but serves as a help to the pilots. They can offer: maintaining flightplans, conducting pilot briefings, relaying clearances and broadcasting weather. At selected places the FSS also provides VFR aircraft with En Route Flight Advisory Services.

I know it's seems a bit tricky, but it's not really that hard. Most of the work is done by the ATC. Let's follow an example:

Stage	ATC	Comments
1	DEL	First we contact the Clearance delivery, here we receive clearance for our flightplan, we will probably also get a transponder code here.
2	GND	When we are ready we will contact Ground where we will be approved for push-back and engine start. Then we will be given taxi instructions.
3	TWR	Ground will hand us over to the tower (TWR) just before the runway. TWR will give us the ok to line-up on the runway and the take-off clearance.
4	DEP	Shortly after take-off we will be handed off to DEP, who will control us during most of our climb.
5	CTR	The center will control us during the en route phase.
6	APP	Center control will then hand us off to approach control who will lead us up until we are established on the ILS.
7	TWR	TWR will once again clear us, but this time for landing.
8	GND	After having vacated the runway we are handed over to ground who will lead us right on the ground.

So we have now been lead by eight different stations, in real life there would have been much more, for example a lot of the times GND will be separated into two stations, and there will probably be a large amount of switching between stations when flying en route too.

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