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Online Flying

Lesson 2 - Aircraft Control at Small Airfields


This is a series of tutorials and practical flying exercises prepared by CIX VFR Club to introduce members to online ATC and to enable them to learn at their own pace how to use it. Each lesson consists of a Groundschool section on aviation law and theory, and a Practical exercise to fly using the information in the Groundschool.

There are three basic types of Air Traffic Control with which Club members flying VFR will need to know about.

  1. Air Traffic Control (ATC)
  2. Aerodrome Flight Information Service (AFIS).
  3. Air/Ground radio (A/G).

The difference between them is all to do with the level of information or instruction given to pilots. For this lesson, we will examine the second two only, AFIS and A/G.

For a long time VATSIM had almost no ATC services other than full ATC, but from time to time A/G and AFIS services are coming on line as pilots recognise the fun to be had flying small aeroplanes around little aerodromes. Therefore all types of service are covered in this series of lessons.

VATSIM has produced a detailed document describing the Services available at AFIS and A/G Aerodromes, and club Member Matt Allen has written a simpler version which provides all the AFIS ATC Dialogue you need to know as a Flightsim pilot.

Aircraft Movement Control at the Smaller Airfields


Read Chapters 1 and 2 of the Club's Air Traffic Control Manual for VFR Pilots which may be found on the web site at VFR Pilots.pdf

The CAA publishes its own Radiotelephony Manual, known as CAP413. This contains absolutely everything to do with aviation radiotelephony, which is why the Club published its own abbreviated version for VFR flight on VATSIM.

Air Ground Radio


Air/Ground Radio (A/G) is used at most small general aviation (GA) airfields and provides information only to pilots who must make their own decisions based on the information given. This information is usually provided in the form 'Carry out this manoeuvre at your discretion'. E.g.

Golf Bravo November Oscar Zulu Runway in use 09 left hand circuits QNH 1013, taxi at your discretion


Outside the Aerodrome Traffic Zone (ATZ), the Air/Ground Radio Operator cannot provide a service except aerodrome information to allow inbound pilots to position for landing. E.g.

Golf Bravo November Oscar Zulu runway in use 27, left-hand, QNH 1011

Both the above sentences spoken by the air/ground operator are not instructions, but information.

Aerodrome Flight Information Service

Under an AFIS service, used at slightly busier aerodromes, pilots are given instructions when on the ground, except on the active runway, and information and advice when airborne within the Aerodrome Traffic Zone (ATZ).


The AFISO gives a taxi instruction, but only advice for takeoff.

Golf Bravo November Oscar Zulu taxi to hold Charlie

And then

Takeoff at your discretion

The first of the above sentences spoken by the AFISO is an instruction, but the second is information only. This is the most important distinction between an Air Ground Station and an Aerodrome Flight Information Service.


Outside the ATZ, the Aerodrome Flight Information Service Operator (AFISO) cannot provide a service except aerodrome information, to allow inbound pilots to position for landing. This will be given in the same form as that provided by an Air Ground Radio operator.

Golf Bravo November Oscar Zulu runway in use 27, left-hand, QNH 1011

The pilot has to decide whether to join the circuit overhead or downwind, making the appropriate normal circuit calls which the AFISO will simply acknowledge.

Golf Bravo November Oscar Zulu joining overhead for runway 27 left hand

When you call final, however, he will respond with (or something similar to)

Golf Oscar Zulu land at your discretion surface wind 340 at 10 knots.

To which you should acknowledge

Land at my discretion runway 34 Golf Oscar Zulu


It's an easy exercise. but one well worth doing. Make a booking with the Club's Chief Flying Instructor to practice some simple radio exchanges. This is normally done at Manchester's Barton aerodrome, EGCB, which has an AFIS service, but it can be done at other aerodromes by arrangement. At the arranged time, log into the Club TeamSpeak and establish contact with the CFI.

Position an aircraft at the aerodrome and log into VATSIM. Tune the radio to the aerodrome's frequency, which will be given you by the CFI, if you don't know where else to find it. Then sit and have a dialogue with the AFISO both on the radio frequency and on TeamSpeak to get used to the exchange of instructions with an air traffic controller. There may even be other traffic using the aerodrome, inbounds, outbounds and circuit traffic, so that you can listen to the exchanges between pilot and controller.

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