ATC tutorial: Difference between revisions

{{Main article|Air Traffic Control}}

In order to be able to effectively and reliably communicate, ATC and pilots agree on a set of keywords and jargon. This may vary between regions and the like. English is the agreed language for internaltional flights. (Could someone check if this is the case?)

==Lesson 2==

Now, we'll have a look at each of the positions in details:

===_APP (Approach)===

Approach is the most complicated position. Approach controllers deal with all traffic arriving and leaving (unless there is a departures controller - unusual). The main aim, as always, is to keep the aircraft arriving and leaving separated. For departing traffic, the aim is to get them going in the right direction and give them to center as soon as possible; for arriving traffic, the aim is to get them onto the approach (the correct height and heading) so that they can follow an electronic system (the ILS) which gives them exact guidance onto the runway, and then you can hand them off to the tower, who will clear them to land and try and get planes taking off in between the landings.

The clearance can be given whilst on the ground, and is given by Clearance Delivery (_DEL) if one is online, else the GROUND (_GND), or TOWER (_TWR) controller. The pilot must read-back the whole clearance, to which you confirm by saying 'readback correct'. The Squawk code is a number used to identify the plane. It can be seen on the flight plan (will default to 1200) and means - in the real world - a controller can tell the dots apart as each one has a number. Just assign an available number in the 5000 or 6000 range (eg: 6001, 6002, 6003, etc.).

Here a push-back and start-up means he wants a vehicle to pull the plane away from the buildings so he can start his engines... this is a real-world call, and is not used in the virtual world, so just approve it. He might skip this entirely and just ask if he can taxi, otherwise say:

B-ELIO will then call you when he's ready to taxi. Note you don't have to type B-ELIO, just click on his icon on the screen and ProController automatically inserts it for you. You can often just respond with 'roger' or 'rgr' which means you've heard what the other person has said, or 'wilco' which means you have heard and will obey. When he calls to taxi:

Hold short asks the plane to get close to the point given (here, the runway) without actually getting on to the point. Each runway has a line painted on the ground (the holding line) at which a plane waiting to take-off will wait until he is cleared onto the runway (tower's duty). If you put the plane on the runway, tower might be landing a plane and this plane might well land on top of it! The altimeter is given now so that you are sure that the plane has the correct altimeter setting, and is just good practice. Even with it in your ATIS, and their take-off checks, it never hurts to be safe. Your aim as ground is just to get a queue ready for takeoff so that tower has aircraft ready to takeoff when there's a gap in arrivals.  

If you were awaiting a plane to land, you could just leave the plane queuing, but if you are ready to have him on the runway tell him to get into position on the runway. Remember, it is your job to get aircraft onto and off the runways as quickly as possible, so that planes can land and take-off quickly:

One thing to note, Europeans may use the terminology 'line up and wait' in stead of 'position and hold' - it means exactly the same. You may also use a conditional clearance, to make your job easier:

The plane may give a call back when he's ready like 'ready to go' or 'on the numbers' or 'in position'. If not, just wait until his icon stops moving and give him his takeoff clearance:

The plane will commence his take-off roll, and - as soon as he is airborne - you want to get rid of him and get onto your next plane. You initiate the hand-off to approach, and handoff as soon as (s)he accepts. So now, onto approaches dealings...

Let's look at how the hand-off occurs this time:

This time, because the plane is in the air, you want to acknowledge you can see him on the radar:

'''Some examples of these:'''

What is the QNH? This is an altimeter setting. As the plane will shortly be moving back to local pressure, and not the flight level standard pressure, the pilot must know the local pressure. This ensures that his diagrams which give him the height of the airfield above sea level are correct -- if everyone used a standard altimeter setting at low altitudes the airport's height would seem to fluctuate over a period of hours by a few hundred feet! And finally:

I'm not sure how we ended up at Heathrow, but that's another story!

The orange line shows the 'intercepting the localizer' as the plane will continue to fly this heading until the ILS tells it to turn right onto the center-line of the runway. As soon as the plane reports it's established on the localizer (it has direction signals), it can be cleared for the approach and told to descend with the glideslope which gives the plane height signals. The glideslope and localizer give precision approach information and are known - together - as the ILS (Instrument Landing System). Then get the plane to the tower, because - remember - you may well be dealing with planes taking off which you need to get out of your air-space, and other planes trying to get established on the ILS, as the tower wants a steady stream of well-separated planes on the ILS. You hopefully now know what you're supposed to be doing, but how do we do it. We'll look at each stage in turn.

Great... B-ELIO will now get to OCK and be at 8,000. Just before he gets to OCK, you need to issue the next instructions so that he can be ready for them:

OK so far? Now let's head him towards the airport. This is the base leg:

This is where judgment and cunning use of the feature for monitoring heading and distance come into play. It is also your duty to give the plane the frequency for the ILS (in the form xxx.xx) which can be found at www.ivao.aero/db/ss (or from database, sector system) using the search facility. The plane just hit the extended center-line at least 8NM away from the airport, so make sure you issue the turn to 45 at the correct time, otherwise B-ELIO will miss the ILS. Right place, so...

B-ELIO will now get himself onto the localizer and call:

This is your cue to clear him for the approach and allow him to descend (otherwise he'll fly perfectly over the runway at 2,500ft). This is done with the following command:

That's your job done! As the approach controller you have the most work, so don't be afraid to give planes holds. A hold is a request for a plane to circle around a given fix (e.g.: a VOR) at a given height until you can do something with them. In fact, if you have lots of planes all circling a VOR, it's known as a 'stack' because the plane's are stacked there. So, we could get three planes holding at the OCK VOR (while we waited for traffic to decrease) at 6,000 ft, 8,000 ft and 10,000 ft and add new planes to the top and take planes ready for the approach from the bottom. To give a hold, the basic command is:

Disaster! You've got a propeller aircraft doing an approach and you've started a 747 on the same approach behind it. There's nothing to hold it at, and there getting very close -- what do you do? You could take the plane away and start the approach again, but using an orbit -- a circle to the left or right and then on the original heading -- will increase your time, just give:

Also, sometimes as approach you will want to slow a plane down to ensure that it isn't conflicting with a plane already on approach in front... if they are too close, the second plane will end up missing his approach because the plane in front will still be on the runway.

Anyway, back to our imaginary flight in which B-ELIO is flying the approach and is back with the tower...

The pilot will report to the tower:

You can then give the landing clearance, or - more likely - you can delay the clearance until he is 8NM from the airport and so are more certain that he will be able to land. The 8NM point of the approach is marked by a special device that causes a tone and light in the plane's cockpit. This device is known as the outer marker (O/M or OM). You can ask the pilot to tell you at this point for his clearance:

Your aim as the tower is to clear the plane to land to avoid it having to miss its approach, and get other planes taking off between the landing planes, whilst maintaining separation between the planes. You must remember to account for the fact that a plane trying to land may miss its approach, and have to fly past the airport -- so make sure you turn slower planes away from the airport quickly in case a jet needs to continue past the runway.  

After B-ELIO has landed, while he's still on the runway, you still control him. You want him off your runway as soon as possible, so you can land the next plane (otherwise, if he's still anywhere on the runway, you'd have to give a landing plane a missed approach), so:

And your job is done... let's look at a worse scenario. You landed a plane before B-ELIO and for some reason it hasn't been able to get off the runway yet. You must not let B-ELIO land whilst any other plane is on the runway, so you order B-ELIO to miss his approach:

Approach will then climb the plane back to 6,000 ft (as it is almost a departure now) and complete the down-wind and base legs again (possibly on the other side of the airfield, depending on traffic). The plane can then be vectored back onto approach by the approach controller, and then given back to tower to try again. Of course a plane can initiate their own missed approach.

Once, B-ELIO is back with the ground controller, having taxied just off the runway, he will be given instructions to taxi to the terminal building. If there is no ground, the tower controller can just give a 'taxi to parking' order without specialized instructions.

That concludes the average flight in ProController, but the next (and last) page of this lesson contains some information that you may want to know, for example: the words used to represent single letter (e.g.: alpha for A in ATIS, and lima for L as in 'taxi-way lima' as opposed to 'taxi-way L').