| Clearance | Apron / Ground | Tower | Terminal | Centre | FSS |
Tower controllers are responsible for the safety and separation of landing and departing traffic. They are also responsible for VFR traffic within the airport control zone. It's the Tower controller that defines the active runways for a given airport, and ultimately decides who lands on which runway. The tower controls the upflow of traffic into controlled airspace, and is an essential link in the chain of ATS services. It is essential for Tower controllers to maintain constant contact with the Terminal/Centre controller, as well as ground.
The tower is responsible for all active runways, and for VFR traffic operating within the control zone (usually 5 or 7nm diameter, Surface to 3000ft AAE above airport elevation). Important: In some airports Tower will take responsibility of some taxiways - be sure to check the local procedures.
When Clearance and Ground control are not online the Tower controller takes responsibility of the these positions as well.
In addition to the general guidelines a Tower controller must:
You will need the following additional information:
It is your job to designate the active runway(s) according to wind, noise abatement procedures, and eventually ease of taxi. Refer to local airport procedures for local runway assignment procedures. Where none exist use the longest/best serviced runway if winds are less than 5 knots, and take the crosswind component into account if wind is 5 knots or greater. Be sure to keep all nearby ATC informed of runway and ATIS changes using the ATC channel. When selecting the runway-in-use, other factors such as traffic pattern, the length of runways or landing runs and the approach aids available should be taken into account. At certain aerodromes more than one runway may be in use at any one time (larger airports).
When traffic / procedures permit try and accommodate requests for use of other runways. If using an inactive runway be sure to inform ground, as he may be using the runway to taxi aircraft.
If ground is online, traffic will be handed over at or shortly before the holding position for the selected runway. If no ground is online aircraft should give you a call when they are ready. In this situation you would assume the duties of the Ground controller.
Departing aircraft may be taxied into position at your discretion, but you have to request an IFR release from Terminal/Centre before you clear aircraft for take-off (IFR traffic only). Two different variations to the release are available:
Note: when line-up will take place at a position other than for a full-length runway departure the intermediate point of entry shall be included in the line-up instruction as per the Canadian phraseology guide. Moreover, do not use conditional clearances or instructions for the movement of airport traffic. Misinterpretation could be caused by a conditional clearance or instruction such as: proceed across runway XX after departing DC9.
The tower controller is responsible for issuing take-off clearance and advising pilots of any variations to the surface wind or other significant changes to meteorological conditions.
Take-off clearance may be issued when aircraft is at or approaching the holding bay or the threshold of the departure runway.
If the take-off clearance has to be cancelled before the take-off run has commenced, the pilot shall be instructed to hold position. If the take-off run has commenced and there is an important safety reason as to why the aircraft cannot take off, the pilot shall be instructed to stop immediately.
If for any reason, you need an aircraft to take off immediately, the instruction "Cleared for immediate take-off" may be added. You should always ask the pilot before giving the clearance if he is able to accept an immediate take-off. It is expected that the pilot will act as follows:
Always respect minimum wake turbulence spacing.
If terminal or centre controller is online, arriving traffic will be handed off to tower when established on the final approach.
If there is no terminal or centre opened, aircraft are supposed to call before they are established on the final approach, approximately 15 to 20 nm from the airport. Do not assume terminal responsability as it is a position located above you. Ask the pilot to report established on final approach.
Only clear an aircraft to land when the preceding aircraft has:
A landing aircraft shall not be permitted to cross the beginning of the runway on its final approach until a preceding aircraft, departing from the same runway, is airborne.
If the runway is occupied by another aircraft when an aircraft is on final approach, and it is not planned that the runway will be free when the aircraft on final will reach the runway threshold, it must be instructed to carry out a missed approach.
Here are some other reasons to ask an aircraft to commence a missed approach:
Aircraft should then be told to follow the published missed approach procedure, or an alternative clearence given which has been provided by the approach controller.
Ensure you inform the Approach controller as soon as the aircraft begins the missed approach procedure.
All VFR traffic inside the airport control zone is under Tower's responsability and service offered by ATC depends on the control zone type of airspace.
Departing VFR aircraft call tower when holding short of the departure runway, when ground is online. In the take-off clearance, specify what you want the aircraft to do after departure. For example: "left turn towards the East, not above 1 500ft, cleared for take-off runway 24L".
Once cleared of the control zone, release VFR traffic to enroute frequencies or hand if off to the next controller depending on the type of airspace surrounding the control zone.
We suggest you to review the VFR Terminal Chart of your area for more details on the airspace. We also suggest you to review the Canadian phraseology guide for VFR phraseology.
Arriving VFR aircraft will call prior to enter your control zone, or will be handed off by previous controller before it enters your control zone.
Clearance to enter the circuit is issued when the aircraft is still some distance from the airfield to enable the pilot to conform with the traffic circuit. Information concerning landing direction or runway in use and any other necessary instructions are given at the same time (wind, altimeter, squawk code..). Landing clearance is normally issued when aircraft is turning on the final leg.
Once the aircraft has slowed down on the runway, issue exit instructions and hand off to ground controller as soon as possible (if opened) to avoid making the aircraft stop after clearing the runway.
We suggest you to review the VFR Terminal Chart of your area for more details on the airspace. We also suggest you to review the Canadian phraseology guide for VFR phraseology.
IFR Hand off
For arrivals: whenever possible anticipate hand-off to ground so that the aircraft won't have to stop. Don't wait for aircraft to report clear of the runway.
For departures: hand off to Departures is with the take-off clearance, or once airborne is there is a need to keep the aircraft on your frequency for traffic (e.g. VFR traffic near the departure path). Some airport's procedures may vary, and should be respected.
Coordination with other units
Tower must maintain constant coordination with ground if opened, and with terminal (or if terminal is not opened, any unit assuming that position).
Visual control
With the release of IvAi, which enables you to use your flight simulator to control visually ground control can become extremely realistic, especially as you will most likely see exactly where the aircraft is located as there are no sector errors. On the other hand FS scenery becomes an issue, so always interpret what you see with a grain of salt as far as aircraft on the ground are concerned.
This section includes additional MANOPS procedures that have been approved and can be applied in Canada.
No special procedures exist for this position at this time.
Tower controls runways and VFR inside the control zone. Tower must be aware of all IFR approaches on all runways.
Ground will bring aircraft to the hold short line of the departure runway, then aircraft will call you for departure. Most of the time, when the aircraft calls you, you can clear him for takeoff right away using:
[callsign], call [station / freq] airborne, [any instructions in case of a non-SID departure], cleared for take off runway [xx].
Jazz 123, call departures on 118.9 airborne, cleared for takeoff runway 24L
Departures control can either be terminal or centre (_APP, _CTR). Of course do not tell the pilot to contact departures if there is no other ATC online. Instead, use the exit of controlled airspace phraseology (see the Canadian phraseology guide).
Sometimes, pilot cannot be cleared for takeoff as soon as he calls you. For example, if you have an aircraft on final for the same runway and think the departure won't have time to depart before the arrival. If you are not confortable, use a larger separation between both aircraft. Every situation is different according to aircraft type too, a light aircraft takes off more quickly but usually flies much more slower then another medium aircraft. As a general rule on IVAO, if the arriving aircraft is 6nm or less on final, keep your departure holding short of the runway ("hold short runway 24L, traffic Boeing 737 5 miles final"). As soon as the arrival touches down (and considering there is no other arrival behind), you can tell the departure to line-up and wait on the runway until the arrival exits the runway.
[callsign], line up / line up and wait runway [xx]
If you clear an aircraft for takeoff in front of an arrival, make sure both pilots are aware of each other, because on IVAO, some pilots may take position on the runway and wait there for a while to prepare takeoff procedures.
For arrivals, if terminal or centre (_APP, _CTR) is online, he will transfer you the IFR aircraft inbound and established on the final approach at about 10 nm from threshold. If no other ATC is online, make sure pilots call you on final or a little bit before. From the moment the aircraft is on final, you can clear him to land unless you expect a departure from the same runway before its landing. Use:
[callsign], winds [winds], [exit instructions if any] cleared to land, runway [xx].
Air Canada 123, winds 220 at 10, cleared to land runway 24L
If you expect a departure from the same runway before its landing, do not clear him to land. Instead, use:
[callsign], Tower, number 1 runway [xx], winds [winds].
Number 1 means he is first to land but not cleared yet. You also can give a reason. Once the departure is in the air, don't forget to clear the arrival to land!
If you have 2 aircraft on final for the same runway, tell the second pilot:
[callsign], Tower, number [x] behind [aircraft type and distance from threshold], winds [winds].
Number 2 means he is second for landing and not cleared yet. Most of the time, terminal / centre managed the spacing between them but you have to monitor that the separation doesn't decrease too much. You can give speed restrictions to ensure proper spacing. In the worse case, you can ask unwanted things like a 360 turn or missed approach for the second aircraft. Caution, if you have a 3rd aircraft, the 360 turn is probably a bad idea.
To speed aircraft movements when exiting the runway after landing, wait until the aircraft slows down (less then 50 knots), then provide taxi instructions right away:
[callsign] left/right on [taxiway], contact ground [xxx.xx] when clear.
If no ground controller is online, do not say to call ground, instead give taxi instructions to the apron (assume ground responsabilities when ground is offline).
VFR operations: it is very important to know the size of the control zone when working VFR aircraft, because all VFR aircraft inside the zone have to contact you and sometimes get permission to enter. Arriving aircraft will call you before entering the zone, and release departing aircraft when clearing the zone. Same thing for overflights. Depending on the classe of airspace, don't forget to give VFRs restrictions so they won't get in the way of other aircraft. Arriving aircraft must be cleared to join the circuit if cleared of conflict using:
[callsign], Tower, cleared ([right/left] hand) [joining leg] runway [xx], report downwind (or turning final etc.)
If there is already an aircraft in the circuit, make sure the second aircraft can see the first one and follows him.
We recommend you use the NARDS colour scheme (available in the downloads section) with Ground detail, VORs, NDBs, Runway centrelines, LO airspace and LO airways turned on.
Set your altitude filter to the top of your control zone + 1200ft (e.g. CZ is SFC-3200; you would set the filter to SFC-4400ft), and use a range between 12 and 25nm, or as specified in the airport procedures.
See MANOPS section 300 for complete information.