Approach Study Guide
Introduction
This manual will show you the basic skills that you will need as an approach controller. This manual is meant to support your training, but it cannot replace an approach lesson held by the responsible Regional Group. This guide can only show you basic techniques, but it cannot provide you with descriptions on how to solve specific situations in your local area. Nor can this guide replace practice on the network. The step up from tower to approach is probably the hardest part of your ATC training on Vatsim. Be warned, you will need a lot of practice online before you can realistically pass your CPT. However, there is no need to be afraid. The ATC mentors have the necessary experience to help you throughout your training and you are neither the first nor will you be the last to pass his/her CPT on approach.
Most importantly: Have fun!
Note: This Guide has a lot of content and will be overwhelming at first. Unfortunately, there is no way to avoid reading the whole thing as a first step in your training. However, some information will make a lot more sense once you have gained more experience on the network. You are therefore highly encouraged to read this guide or parts of this guide several times throughout your training. For example, you can use it to read up on specific topics that you feel unsure about.
Basic Theory
Radar Controllers
A real controller covering ground positions always has a direct look at the aircraft he is responsible for. Departure and approach controllers are both radar controllers. The only things they have as reference is the picture on their scope, usually with the data read out from the secondary surveillance radar (SSR) and the radio transmissions made by the pilots. We will get back to that in the paragraphs about radar identification.
Airspace Classification
Airspace Classes in Germany
ICAO allows for a total of seven airspace classes (named A to G). These airspace classes differ from each either in one or more of the following points:
- Weather minima
- Flight rules restrictions (VFR or IFR)
- Instrumentation and equipment requirements (transponder, com radio, nav)
- Contact with ATC and clearance requirements
- Separation
The specific weather minima required for each airspace will be ignored in this guide as they are less relevant to Vatsim. We can assume that every VFR pilot automatically complies with the required weather minima that he/she set up in his flight simulator. The following table summarizes the important differences between all airspaces in use within German airspace.
| Class | Protected? | Allowed Flight Type | Separation | Speed Limit |
|---|---|---|---|---|
| C | Yes | IFR/VFR | IFR/IFR, IFR/VFR, Traffic info for VFR/VFR | 250kts for VFR below FL100 |
| D | Yes | IFR/VFR | IFR/IFR, Traffic info for IFR/VFR, VFR/VFR | 250kts below FL100 |
| E | No | IFR/VFR | IFR/IFR, Traffic info about known traffic for IFR/VFR, VFR/VFR | 250kts below FL100 |
| G | No | VFR | FIS only | 250kts below FL100 |
As a tower controller you were previously used to a D CTR where VFR needs a clearance to enter by ATC and received traffic information about other traffic. Lots of approach airspaces within Germany mainly consist of airspace D requiring little adaptation from you. However, as an approach controller around one of Germany’s major airports you will be confronted with mainly airspace C. As a result we need to handle VFR slightly differently which this guide will describe at a later topic.
In order to give you the complete picture, it is worth mentioning that airspaces A und B are similar to airspace C but B requires separation between VFR/VFR while airspace A only allows VFR traffic that has been authorized by the responsible authority.
There used to be areas with airspace F in Germany but they have since been replaced by RMZ (Radio Mandatory Zone) and TMZ (Transponder Mandatory Zone) that require VFR traffic to monitor a specific radio frequency or squawk a specific squawk code. Both zones are part of airspace G and therefore remain uncontrolled.
Implementation of Airspace Classes in Germany
The following picture shows the airspace structure within Germany.
Above FL100 (exception FL130 in some places around the Alps) you find airspace C. Below airspace C there is usually an airspace E followed by airspace G close to the ground. In highly congested areas of airspace G and/or close to uncontrolled airfields you will find TMZs and/or RMZs as described above.
Around controlled airports you will usually find either airspace C or airspace D followed by a CTR consisting of airspace D. However, there are lots of exceptions and every airport has a different airspace structure. Therefore, it is essential that you familiarize yourself with your local airspace structure before you start controlling. This can easily be done by using the DFS AIS service that includes a chart of the airspace structure in all of Germany (free registration required).
Lastly it should be mentioned that airspaces C and D are mainly for protecting busy IFR traffic routes from unidentified VFR traffic flying close by. You should therefore avoid descending IFR traffic outside of airspace C and D into airspace E whenever possible. There are airports where IFR traffic is required to pass through airspace E but at most busy German airports there is usually no reason to let IFR traffic leave the protected airspace.
Terminal Maneuvering Area (TMA)
The TMA is the airspace immediately around a CTR that all traffic to or from a controlled airport has to pass through. The majority of your responsibility will be the traffic inside the TMA. The dimensions of your TMA and the sector you are responsible of is strictly defined by your FIR.
It must be emphasised that parts of your TMA are always airspace E that you are responsible of. The TMA consists of several different airspace classes and it is your job to remember where one airspace class ends and another one begins in order to keep IFR traffic inside controlled airspace and to guide VFR appropriately within uncontrolled and controlled airspace.
Identification
When radar was first invented it only existed as a primary radar. A primary radar only shows one dot on the screen for each contact it detects. Modern air traffic radars are enhanced with a secondary radar in combination with a mode A/C/S transponder.
The mode A/C transponder sends its squawk code and the current flight level back to the secondary radar where this can be matched with a primary target. Now we know which squawk code fits our primary target. Modern Radar Data Processing Systems are capable of linking this discrete code to a flight plan and thus obtaining a callsign indication on the Situation Radar Display.
Mode S transponders are able to downlink multiple other data from aircraft. For identification a discrete code is no longer required, as one of the parameters sent by a mode S transponder is the Aicraft ID (Callsign), which can be directly displayed on the Radar Screen. Other useful data that can be obtained via Mode S are for example Selected Altitude, Ground Speed, Indicated Airspeed or Vertical Rate. Unfortunately it is not possible to simulate Mode S within VATSIM environment.
Before offering Radar Services to pilots, identification shall be established and the pilot informed. There are different methods of identification depending on the type of surveillance used (primary or secondary radar).
Primary Radar
- Position Report and Heading/Track
- Departing aircraft within 1 NM of runway
- Transfer of Identification
Secondary Radar (Mode A/C/S)
- Recognition of Aircraft ID (Callsign) in an SSR Label
- Recognition of discrete squawk code
- Observing the setting of an assigned SSR code
- Observing the setting of Squawk IDENT
- Transfer of identification
The most common way to identify an aircraft in our simulated environment is “Recognition of Aircraft ID (Callsign) in an SSR Label”. So basically, whenever you see a label with a callsign, this callsign is linked to a flight plan and the aircraft is properly identified. If a pilot is unable to turn on his transponder, you can identify him using the methods listed for primary radar. The best way to do so is to request a position report with heading and compare the location to the primary blip on your Situation Radar Display.
Most VATSIM controllers use “easy mode” in Euroscope where Euroscope cheats and always shows callsign and all necessary information no matter what the pilot squawks. However, there are some RGs that offer a setup for “S mode”. Using this mode it is possible to have aircraft entering your sector with no callsign indication. Thus you have to choose an appropriate method from the one listed above to link the indicated squawk with flight plan data.
Verification of Level Information
Often wrongly considered as a part of the identification process, a pilot’s level report is absolutely independent from the procedure shown in the chapter before. As already known a mode C transponders gives information about the pressure altitude of an aircraft. To use this level indication for vertical separation a controller is obliged to verify this level information as soon as possible after initial contact. To do so you simply compare the reported level of the pilot to the one indicated on your radar screen. Taking into account real life regulations, a discrepancy of 200ft is allowed to exist. Within VATSIM’s simulated environment, a higher offset can be accepted. If the reported level differs significantly from the one indicated on your radar, it is useful to instruct the pilot to turn off his transponder to avoid false conflict alerts. Instead, you have to work with level reports to ensure vertical separation.
Methods of control
As blatant as it sounds, you as a radar controller have the ability to influence an aircrafts
- Lateral path
- Vertical path
- Speed.
However the pilot may always decline an instruction if he/she considers this instruction to be harmful to the aircraft. Therefore, it is essential that you understand the physical limitations of an aircraft. We will talk about some of these limitations later.
The most basic instructions in order to influence these points are
- Vectors
- Climb/Descend and
- Speed Instructions.
It is also worth noting that any procedure that ATC clears (SID, STAR, Transition, ILS...) will dictate at least one of the points above. You should view SIDs, STARs and Transitions as predetermined vectors that the aircraft will fly to. If you are ever unsatisfied with any of the procedures for a particular aircraft (maybe the aircraft is currently flying towards another aircraft and would end up ontop of the other aircraft) then you should immediately step in and give a better suited vector yourself.
Coordination & Handoff
For your sector there is always a standard operating procedure (SOP) or letters of agreement (LoA) that require you to issue certain instructions for the next sector or allow you to issue instructions to aircraft not in your sector. This can either be done through designated airspaces where you are always allowed to use parts of the airspace of other controllers or through releases for certain aircraft (e.g. EDDF inbounds via SPESA are released for turns after handoff from CTR to APP). Without these releases you have to wait for the aircraft to enter your sector before giving instructions!
The so-called Handoff that you know from your TWR training is executed as a silent-handoff within Vatsim Germany. You will transfer the aircraft TAG to the next controller in the same moment in which you instruct the pilot to contact the next station. The other controller will accept the transfer of the TAG as soon as the pilot makes the initial call on the next controller's frequency.
Handoffs do not include releases for the next station! Even if you give the next station a release for an aircraft, you are responsible for this aircraft until it leaves your airspace. You must never hand off aircraft that are in or close to being in conflict.
Every deviation from the SOPs or LoAs have to be coordinated with other stations.
ATC stations within the Approach Sector
In general the approach sector can be divided into Departure, Arrival and Feeder. These stations can further be divided into north and south sectors.
Departure controllers are responsible for all departing traffic while Arrival controllers are responsible for all arriving traffic. Both stations have clearly defined airspaces that they have to adhere to unless deviations are specifically coordinated. Both stations have to ensure sufficient separation between aircraft before handoff to the next station. The last station of the three is the Feeder or Director controller that is responsible for turning aircraft onto the ILS. This station does not have its own airspace but works within the approach airspace. As soon as Arrival transfers the aircraft to Feeder, Feeder is responsible.
Separation
Radar Separation
You should remember from the Airspace Classes that inside airspace C IFR has to be separated from other IFR and VFR traffic. Inside airspace D we need to separate IFR from IFR. This means that we need to ensure that there is always either 3NM horizontally or 1000ft vertically between these aircraft. This is called Radar Separation. As soon as we drop below 3NM horizontally we need to ensure at least 1000ft vertical separation! 800ft and 2.5NM is not enough and is considered a loss of separation!
Please note that there are exceptions to this rule depending on the procedure. For example, some ILS approaches can be used independently which means that, for aircraft on different ILS, Radar Separation does not need to be applied. Furthermore, the horizontal separation can, one some airports and under certain conditions, be reduced below 3NM. This is dependent on your local procedures and will become clear during your trainings. Also note that above FL245 the horizontal separation needs to be 5NM instead of 3NM.
Wake Turbulence Separation (WTS)
As soon as a wing produces lift it also produces a wing tip vortex. That means they are only created once the aircraft has rotated and they stop being created once the aircraft has landed and touched down with the front wheel. These turbulences are incredibly strong and can easily flip a smaller aircraft on its head. Therefore, if one aircraft is crossing or following the flight path of another aircraft on the same altitude or less than 1000ft below, additional horizontal separation needs to be applied. This separation also needs to be applied when two aircraft are approaching different runways less than 760m apart. WTS is applied between all aircraft, including VFR. However, it does not need to be applied between
- Arriving VFR aircraft and
- Arriving IFR aircraft on a visual approach.
However, if the pilot requests sufficient WTS to the preceeding aircraft, ATC has to ensure the spacing listed below.
Note: WTS has to be applied for departing VFR aircraft. Aircraft on a touch and go/low approach are first considered arriving and are then considered departing once they cross the threshhold. So in such a case you will have to tell the pilot to follow a preceeding aircraft visually but once it has crossed the threshhold, you have to ensure that there is enough separation between it and the preceeding departure. If that is not the case, you have to tell the pilot to perform an early left or right turn.
For this purpose the aircraft are divided into the categories Light/Medium/Heavy/Super depending on the Maximum Takeoff Weight.
| Category | MTOW | Examples |
|---|---|---|
| Light | MTOW ≤ 7000kg | C172 |
| Medium | 7000kg < MTOW > 136000kg | A320 |
| Heavy | MTOW ≥ 136000kg | B753 |
| Super | A388/AN225 | A388 |
The B752 is the only exception to this rule as it is counted as a Medium when following and a Heavy when preceeding another aircraft.
The required separation for different categories of aircraft can be found in the following tables. Preceding aircraft: Medium
| Following Aircraft | WTS |
|---|---|
| Medium | - |
| Light | 5NM |
Preceding aircraft: Heavy
| Following Aircraft | WTS |
|---|---|
| Heavy | 4NM |
| Medium | 5NM |
| Light | 6NM |
Preceeding aircraft: A388 (only in and below FL100, otherwise A388 counts as Heavy)
| Following Aircraft | WTS |
|---|---|
| Super | - |
| Heavy | 6NM |
| Medium | 7NM |
| Light | 8NM |
Visual Separation
Visual separation is mentioned here mainly to give you a more complete picture. In reality and only during daytime may the pilot be asked if he has an aircraft in sight and if he is able to maintain visual separation. Only if the pilots agrees to this, he will take responsibility of the separation and radar separation does not need to be applied anymore.
| Visual Separation Phraseology example |
| "DLH123, confirm RYR B738 on final runway 25R, passing 1500ft, in sight and able for own separation." |
| "DLH123, affirm, traffic in sight" |
| "DLH123, maintain own separation to traffic" |
| "DLH123, maintain own separation" |
MSA & MVA
The earth's land mass has a varying height above sea level depending on your current location and since modern times it's also filled with high buildings and cranes that are obstacles to aviation. In order to ensure safe flying operations the ICAO has defined an almost endless amount of minimum altitudes. The most common ones are
- Minimum Safe Altitude (MSA)
- Minimum Vectoring Altitude/Minimum Radar Vector Altitude (MVA)
- Minimum Enroute Altitude (MEA)
- Minimum Holding Altitude (MHA)
- Minimum Obstacle Clearance Altitude (MOCA)
- Minimum Descend Altitude (MDA)
For us as controllers the MVA is the most important altitude. We must not clear any aircraft below the MVA unless this aircraft is cleared via a published procedure (mostly via SIDs and approach procedures like ILS, RNP etc.). It is worth noting that giving directs is also prohibited below the MVA. These procedures are designed to allow aircraft to operate safely close to the ground, in the vicinity of the airport. For us as Vatsim Controllers the exception to this rule is a radar vectored departure that you know from your tower training. This departure does not comply with the MVA and is therefore not allowed in Germany in real life. However, as it makes our life a lot easier when it comes to difficult pilots, we are allowed to use it on the network.
You will find the MVA of the bigger German airports in the eurocontrol AIP database or through any chart provider. A somewhat outdated chart is also implemented in Euroscope (still accurate enough for Vatsim purposes).
Departure Control
General Introduction
Ideally the departing aircraft contacts the appropriate departure controller at the appropriate time which allows the departure controller to identify the aircraft (see Identification). The pilot will either be flying a SID or a radar vectored departure to a specific point. In both cases you will have to instruct the pilot to climb eventually.
If the pilot flies a SID, you can assume that he will follow the lateral path of the SID, including additional restrictions in regards to altitude and speeds (the last part is the one that does not necessarily work that well on Vatsim). Together with the SID the pilot will have an initial climb clearance. A pilot is not allowed to climb above his initial climb altitude unless specifically instructed to do so by the departure controller (or any other controller). However, pilots on Vatsim frequently bust their initial climb by a few hundred feet or completely ignore it which can cause conflicts. These conflicts are not your fault as a controller but you will have to resolve them regardless. It makes sense to be mindful about this issue and to know how to resolve these situations before they occur.
If the pilot flies a radar vectored departure, you will eventually have to give him a direct to any waypoint on his/her route.
Practical Departure Example
Let's assume the pilot is climbing out of Frankfurt and is calling ATC.
| Initial Call on Departure |
| "Langen Radar, hallo, DLH123 passing 1500ft for 4000ft." |
| "DLH123, Langen Radar, hallo, identified, climb FL 130." |
| "DLH123, climb FL 130" |
In this case the pilot made an appropriate initial call. Often a Vatsim pilot will forget to report the altitude which he is passing. In this case you will have to read out the altitude in Euroscope and report that to the pilot.
| In case the pilot does not report the level he/she is passing |
| "DLH123, Langen Radar, hallo, identified passing 1500ft, climb FL 130." |
Your job is to safely climb the pilot to your upper sector border (or any other transfer level defined by SOP or LoA) before handoff to the next controller. You will have to make sure that radar separation between this pilot and other pilots is maintained (usually by ensuring vertical separation). If the pilot cannot climb straight up to FL130 due to traffic then it is worth to work with step climbs. Firstly, because it is more efficient for the pilot but secondly, because you will free up the initial climb altitude. If there is a faster aircraft coming out of the same runway, this aircraft might close the gap to the aircraft in front and could eventually cause a conflict unless both aircraft are on different levels.
Basic Vectoring
In rare cases vectoring on departure will be required. Sometimes a convenient direct to another waypoint will do the same job but very often there is no suitable direct available that can resolve the situation. DO NOT let any aircraft fly on the SID, if you aren't satisfied with where the SID is leading the aircraft. If ever you don't know what to do in a certain situation (e.g. two aircraft are stuck on top of each other but the upper one should descend and the lower one should climb) then vectors are usually the answer.
If you choose to give a vector, you will have to turn the pilot back to his/her route by giving a direct onto any waypoint on the route (if this waypoint is outside of your sector, you will have to coordinate the direct with the next station).
| Phraseology Examples |
| "DLH123, turn left/right heading 130" |
| "DLH123, proceed direct CINDY" |
Be mindful that strong winds can cause an aircraft to drift to either side instead of following the vector inch perfect.
Arrival Control
General Introduction
At some point the arriving aircraft will leave the airway system and descend towards an airport. Either you or a Center controller will have to clear a STAR, Transition or give a vector in order to guide the pilot from the airway system towards the approach procedure. The job of the Arrival controller is to convert the radar separation discussed before to horizontal separation only. Eventually all aircraft flying towards a runway will have to land on the same piece of land therefore vertical separation will not be possible anymore at some point. When the Arrival controller transfers aircraft to the Director controller, the aircraft should not be on top of each other anymore and they should be spaced far enough to allow Director to conveniently turn them onto the ILS (but not too far in order to use the runway efficiently). The exact distance between aircraft is highly dependent on runway capacity and local SOP.
If the Arrival controller has to take over the duties of the Director, the same rules apply. The Arrival controller would just make his/her own life a lot more difficult if he/she ignored the before mentioned principle.
Anatomy of an Approach
For our first look at Arrival procedures we will look at the most basic STAR and standard approach procedure. In this case we look at an aircraft flying to EDDS with BADSO as its last waypoint.
Arrival segment
In the following picture you find the standard STARs to EDDS.
The BADSO2A STAR that the pilot would use in our case is displayed in magenta. In this case BADSO is the clearance limit that the pilot must not cross unless cleared for further procedures (e.g. cleared for BADSO2A) however on Vatsim the pilots usually don't know where their clearance limit is. The STAR itself leads to an Initial Approach Fix (IAF) (in this case LBU) from which further approach procedures can be flown. STARs in general always lead to a fix from which another procedure can be flown to the runway as displayed in the following picture.
In this picture the Initial Approach Segment is displayed in green, the Intermediate Approach Segment in yellow, the Final Approach Segment in blue and the Missed Approach Segment in red.
| Approach Procedure via the IAF |
| "DLH123, out of LBU, cleared ILS Runway 25." |
Initial Approach Segment
The Intial Approach Segment is defined as the Approach segment between Initial Approach Fix (IAF) and Intermediate Fix (IF). Usually there is more than one IAF like in this case where STG is also an IAF for other procedures.
Intermediate Approach Segment
The Intermediate Approach Segment is defined as the Approach segment between IF and Final Approach Fix (FAF). Please note that there aren't always IFs for all procedures. Sometimes there are only IAF and FAF. The IF allows the pilot to not fly the full procedure but to join the procedure at some point. In most cases ILS approaches will not have IFs while the RNP Approach in our example does.
Final Approach Segment
The Final Approach Segment is defined as the Approach segment between FAF and Missed Approach Point (MAP). In this segment the aircraft descends towards the runway. Please note that strictly speaking the FAF can only be called a Final Approach Fix if you are talking about a non-precision approach. For precision approaches the FAF should be called Final Approach Point (FAP). The RNP approach in this case is designed so the pilot always starts the descend at the Final Approach Fix, at 4000ft, 8.7NM away from the runway. The FAF can therefore be considered to be fixed in reference to the altitude indication.
The ILS approach works with the LOC and the GS. The aircraft might find itself perfectly established on the LOC and the GS at the FAP (8.7NM from the threshhold) but the altitude may only be 3950ft instead of 4000ft. The FAP can therefore not be considered fixed in reference to the altitude indication but only in reference to the actual airport.
However, in practice most controllers refer to the FAP/FAF as the Final Approach Fix.
Missed Approach Segment
The Missed Approach segment is defined as the Approach segment between MAP and IAF where the pilot returns to the IAF in case of a Go Around. The Missed Approach Segment is ALWAYS part of the whole Approach procedure. Every pilot is cleared to fly the Missed Approach procedure as soon as he/she is cleared for the Approach procedure (in this case RNP 25). This also means that if another aicraft is crossing the Missed Approach segment, it is a potential cleared conflict to every aircraft cleared for the whole Approach and not just the aircraft declaring a missed approach.
Transitions
Only in rare cases will an aircraft fly a standard procedure from IAF all the way to the runway as just described. On the more busy German airports the use of Transitions is common (Transitions can also be called RNAV STARs. The only difference is that Transitions are by ATC only while RNAV STARs may be filed in a Flight Plan). Transitions can be any procedure inbetween the Arrival segment and the Approach segment. Transitions can also be a substitude for the whole Arrival segment or can be used between SIDs and the airway system in other countries.
In Germany Transitions are mostly used to artifically extend Arrival procedures to allow for easier staggering of aircraft like in the following picture. You will learn how Transitions are used at your training airport during your trainings.
| Clearance for a Transition |
| "DLH123, cleared LBU25 Transition." |
| "DLH123, cleared LBU25 Transition, descend via Transition 4000ft" |
Types of Approaches
Non-precision Approaches
Non-precision Approaches are Approaches where the aircraft is guided towards the runway with either only one electronic guiding system or by GPS (exception GLS, see below). These Approaches are: VOR, VOR/DME, LOC, LOC/DME, NDB, NDB/DME, RNP (old name: RNAV)
For all these Approaches the aircraft should fly the whole procedure, join the procedure at an IF or be vectored in a way that allows the pilot to be established on the Final Approach Course, in level flight before having to initiate the descend towards the runway. All these Approaches have in common that the approach guidance terminates at the MAP and has to be continued visually to the runway. The minimum necessary visibility (RVR) for each of these approaches is published on the respective charts. Rule of thumb: The more guidance the smaller RVR can be.
Officially, the clearance for every non-precision approach except for RNP/RNAV approaches has to include information about the current position of the pilot. This is ideally the distance to the FAF or IAF or any other known point.
| Non-Precision Approach Clearance in EDDS |
| "DLH123, 10NM from UNSER, cleared VOR approach Runway 25." |
Precision Approaches
The GLS approach will be mentioned here for completion purposes. The GLS is a more accurate and corrected version of the RNP approach and is therefore considered a precision approach. So far only very few aircraft addons can simulate a GLS approach properly. You can consider the GLS to be similar to an ILS with the exception that the intercept onto the GLS cannot be closer to the airport than the FAF. The ILS approach is the most common approach procedure. You can vector any aircraft to intercept the ILS at any altitude as long as it is not below the MVA and as long as the aircraft will end up at or below the Glideslope of the ILS.
The ILS is divided into categories I, II and III. CAT I is for normal operation. During low visibility (see required RVR) you can switch to CAT II and CAT III ILS. This lowers the RVR required for the ILS approach. You as a controller have to announce this to the pilots via the ATIS. For some runways there are multiple ILS procedures. The standard ILS is then called ILS Z. Every further ILS also receives a letter for identification (X or Y) which has to be added to the ILS clearance. These different ILS sometimes only have different Missed Approach Procedures, standard procedures or even different ILS frequencies.
| Example for ILS clearances |
| "DLH123, cleared ILS Runway 25" |
| "DLH123, turn right HDG 220, cleared ILS Runway 25" |
This guide will not mention special ILS proccedures like independent approaches to parallel runways as this is highly dependent on the local procedure of every airport.
Visual Approaches
A visual approach does not really fit any of the before mentioned categories. A visual approach can be cleared as soon as the pilot reports the airfield or a runway in sight. During the whole procedure visual reference with the airport has to be maintained. Only then is the pilot allowed to descend below the MVA. It's important to note that, unlike an instrument approach, the visual approach does not include a missed approach procedure. You should tell the pilot straight away what to do in case of a missed approach.
| Visual Approach to EDDF |
| "DLH123, in case of missed approach follow missed approach procedure of ILS 25L, cleared visual approach runway 25C" |
A special version of a visual approach is a Circle to Land where any Instrument Approach procedure is flown before visually switching to a different runway. Whether this is allowed in combination with a certain instrument approach can be found in the chart of the insturment approach.
| Circle to Land in ETOU |
| "DLH123, cleared ILS Runway 25 followed by circling 07" |
Speed Control
New Trainees overestimate the distance you can generate by applying speed control. Let's start with the most blatant and most important rule of speed control:
Two aircraft with the same Ground Speed and the same heading will maintain their distance. Very often, when two aircraft already have the appropriate spacing that you want to achieve on the runway, you can turn both aircraft towards the ILS, on the same heading and if you give the same speed they will continue to the runway with a constant distance between them.
In all other cases it is essential that you get a feeling for what you can do and what you can't do with speeds. Here is some simple math that will let you calculate how much distance you can achieve with different speeds. Let's assume aircraft A and B are flying to a waypoint and are on top of each other on different altitudes. By how much can we increase the gap between both aircraft if aircraft A is flying 280kts and aircraft B 250kts if both have to fly 30NM before reaching their waypoint? The formula is:
(distance to a waypoint/faster speed)*slower speed = distance that the slower aircraft will have flown when the faster aircraft has reached the waypoint.
In our example aircraft B will have traveled 30NM/280kts*250kts=26.8NM while aircraft A travels 30NM. Therefore, we can increase the gap to only 30NM-26.8NM=3.2NM. As a rule of thumb: 30kts speed difference over 30NM will give you 3 or 3.5NM of spacing - not that much considering that it took 6 minutes for only 3NM of spacing.
Don't worry, you will not have to calculate these things while controlling - although I always have a calculator ready when controlling in case there is difficult situation to judge (e.g. I need to generate 20NM of distance with one aircraft flying 450kts(GS) and the other 340kts(GS) due to different winds on CTR...). However, it is worth looking at significant points of your airspace and calculate beforehand how much distance you can generate with a 30kts (maybe also 50kts) speed difference. If you will receive aircraft via 2 waypoints then measure the distance from these waypoints to the ILS and calculate how much you can achieve with 30kts speed difference. That way if two aircraft are close to each other over one of these waypoints, you can instantly judge if using speeds is enough. If you realize that speeds aren't enough to fix the issue, use delay vectors that can delay an aircraft indefinitely. For obvious reasons it is inefficient to instruct an aircraft to fly fast on a delay vector. Delays should be compensated by using slow speeds early and delay vectors should only be used when speeds are not enough.
Lastly, if you need to space two aircraft apart as fast as possible, use all the speed difference you can generate within reason. As a rule of thumb, if you don't want a gap to decrease, use speed differences of 10-20kts. If you want a gap to slowly increase, use 30-40kts of speed difference. If you want to increase a gap right now and as fast as possible then use 60kts and more! Don't be afraid to make use of the performance margins of the aircraft (although don't use less than 220kts far away from the airport. It will force aircraft to set flaps very early and that is uneconomical.).
It is worth mentioning here that higher speeds (and/or higher altitudes) will greatly increase the turn radius of an aircraft. You should keep this in mind if you work with unusually high speeds close to final. Be advised that the same indicated airspeed on different altitudes will result in significantly differing speeds. You should include a margin of error in such a case. Furthermore, sometimes the wind will be different for every pilot and may cause different Ground Speeds despite both pilots flying the same indicated airspeed. This usually is more of a problem for Center positions but you may encounter it on Approach as well.
Lastly, some suggested speeds and when they should be used.
| Speed | Description |
|---|---|
| 280-300 | further away from the final if you really need to create a gap asap |
| 250 | if further away from the final then somewhat slow, closer to the final 250 is quite fast relative to all the other traffic |
| 220 | standard slow speed on downwind or close to the final or when a slow speed is needed to create a gap asap further away from the airport (usually close to Minimum Clean Speed) |
| 200 | only close to the final just before final turn or on the ILS until FAF |
| 180 | until 6NM Final |
| 170 | until 5NM Final |
| 160/150 | until 5NM Final |
It is also worth mentioning that FMCs will always reduce the aircraft's speed to 240/250kts (depending if Boeing or Airbus) when passing FL100 unless the pilot changed this restriction (hint: Usually they don't). In airspace C the pilots are allowed to fly faster than 250kts but Vatsim pilots often don't know that they are inside of airspace C. So if you ever wonder what the indicated airspeed of a plane is that just descended through FL100... it is almost always between 240kts and 250kts.
Sequencing and Spacing
Creating a good sequence on Final tends to be illusive for most beginning Controllers. This guide will discuss only a few tips of building a sequence. Nothing can substitude experience on the network, especially since the reaction time of Vatsim pilots is hard to judge at first.
The target spacing for each airport is dependent on the local procedure. If you want to allow for a departure between two aircraft then 6NM spacing on touchdown is a good rule of thumb. If you don't, then the target should be WTS or 3NM. No matter what your target is, if you add 1.5-2NM to your target you will get approximately the amount that you need when both aircraft interept since the leading aircraft will slow down and cause the succeeding aircraft to close the distance. If, for example, you want to achieve 3.5NM on Touchdown (safety margin included) then you will want to have between 4.5 and 5NM between two aircraft when both aircraft intercept.
The main issue with the step up from Tower to Approach is that traffic will not stop and hold short. As a rule of thumb an aircraft will travel 0.3NM per 5 seconds on downwind (let's assume 0.5NM). If you imagine this aircraft is on a transition or on downwind for a runway and waiting for the final turn then this aircraft will first travel away from the airport and then has to fly the distance back again on the ILS. Every extra mile this aircraft has to fly before the final turn results in twice the amount of additional miles because of that.
If you turn an aircraft only 2 radar updates too late (10s) then the aircraft has traveled 1NM which results in 2NM extra miles compared to an aircraft that didn't have to wait 10s. You will struggle to fix this mistake using speeds as they simply aren't effective enough to gain 2NM back. If you turn an aircraft 30s too late, the aircraft will have traveled 3NM extra resulting in a total of 6NM more spacing than intended. If you want to achieve 4.5NM but accidentally add 6NM extra, you will have lost more than 50% of your efficiency (that is like someone taking away one of EDDF's arrival runways).
These examples should illustrate why your final has the most priority and why you cannot allow yourself to fall behind your airspace at any point. Lastly some rule of thumbs for when to turn aircraft if you want to create precise distances between them. Assuming the transition is 5NM away from the ILS (it usually is) and an aircraft is on downwind, turning the succeeding aircraft when it is abeam the preceeding aircraft, that is established on the ILS, will result in a distance between both aircraft of 5.5-6NM. Keep in mind that this is the point when the pilot has to turn the airplane and not when you should start speaking. You have to give the instruction before that. Also remember that different speeds can cause the succeeding aircraft to close the distance further. If you turn 0.5NM before the aircraft are abeam, you will create 1NM less (remember the rule before where every extra mile on downwind results in 2NM total delay). Turning an aircraft 0.5NM before it is abeam with the succeeding aircraft will result in 4.5NM. With this rule of thumb you can generate any spacing you want to achieve in the beginning. Eventually your gut feeling will take over and will make applying these rules irrelevant but they definitely help for the beginning.
Point Merge adaptations and examples of actual controlling
The Point Merge procedure usually isn't applied at German airports. In this procedure several aircrafts fly an arc that is a precise distance away from a specific waypoint. When all aircraft have a constant distance to this named waypoint, ATC can proceed one aircraft direct the waypoint, wait until the distance to the aircraft behind is appropriate and then proceed the next aircraft to the waypoint.
However, it does not need an official procedure to apply these principles and these principles can make your life a lot easier. In a way the idea of controlling Arrivals means merging them all onto a single point (the runway).
In the left example we see a standard task for the Arrival controller. The aim here is to ensure good spacing between all 3 aircraft. The distance of CFG and FIN tells us that if they both fly the same speed and if both fly straight towards the ILS, we will have 5.6NM between them on the ILS. Let's assume we want to achieve 4.5NM, in this case we can turn all aircraft straight towards the ILS and fine tune the distance using speeds.
Eventually the FIN will be inbetween the CFG and the AUA and the FIN needs to have a distance of 4.5NM to the CFG and 4.5NM to the AUA. For us this means that the AUA needs to be at least 9NM behind the CFG if we want to fit the FIN inbetween. Right now we have 12NM between AUA and CFG which means we can also turn the AUA straight towards the ILS. We will need to make sure that the AUA doesn't close the gap to the CFG too much which we can control again using speeds. If all works out (spoiler: it will) we will have achieved the perfect sequence without using any Transition or Arrival simply by recognizing opportunities.
In the right example we concentrate on the TSO and UAL and we see that both aircraft have to fly the same distance to DF411 where they will merge. If they fly the same speed they will end up on top of each other - Although with 9NM to go the speed doesn't really matter. Whichever speed they fly, they will end up on top of each other because there is not enough time for speeds to have any significant effect.
We definitely don't want to hand off two aircraft on top of each other to the Director because the whole point of having an Arrival controller is that the controller has to sequence aircraft before they reach the Director controller. In this case the controller should let the TSO continue on present heading and turn the TSO left towards the final behind the UAL.
Holding Procedure
Issuing a Hold
Holding procedures usually refer to a race track pattern that an aircraft flies over a defined position in order to burn the minimum amount of fuel while waiting. This can happen because
- the landing runway is temporarily unavailable (e.g. due to emergency inbound)
- because the next sector has reached maximum capacity or
- because the pilot requests to hold (e.g. in order to work on non-normal checklists).
Especially in the last case, ATC does not necessarily have to instruct a hold but can also vector the aircraft around the airspace until the pilot can continue to his/her destination.
For your training airport and any airport you control later on, you will find Holding Procedures published in the charts. They define which waypoint the aircraft will hold over, what inbound course to fly to the waypoint, which outbound-time (also refered to as legtime) to use, which direction to turn when entering the pattern and the minimum altitude inside the Pattern. If the legtime is not specifically mentioned, it is assumed to be 1 minute at or below FL140 and 1.5 minutes above FL140.
| Hold as published |
| "DLH123, hold over SPESA *as published*, climb/maintain/descend FLxy, expect further clearance in 30 minutes" |
In this example the addition "as published" has been added. This is not part of the standard phraseology but has proven to help Vatsim pilots understand the instruction.
Notice that firstly the standard phraseology includes a level instruction even if the cleared level remains the same. Also notice that the standard phraseology always includes information about the expected delay. This way the pilot can plan ahead, calculate the fuel remaining at the end of the hold and decide if he/she should divert straight away without waiting unnecessarily.
Holds can also be instructed over any other waypoint as long as ATC gives all the information to the pilot that has previously been determined by the chart. An example of this goes as follows:
| non-published hold |
| "DLH123, hold over DF611, descend FL80, inbound track 070, right hand pattern, outbound time 1 minute, expected approach time 1800z" |
Holding Speeds
ICAO has published official holding speeds that are as follows:
- Holding altitude 14000' or below - 230 KIAS
- Holding altitude above 14000' to 20000' - 240 KIAS
- Holding altitude above 20000' to 34000' - 265 KIAS
- Holding altitude above 34000' - Mach .83
- Holding patterns restricted to Category A and B aircraft only - 170 KIAS
However, these can vary depending on the airport. On Vatsim it is also unlikely that the aircraft will fly the published holding speeds. It is more likely that the pilot reduces to minimum clean speed just before entering a holding pattern.
You should not restrict the airspeed of planes inside the holding as it has little use to fly fast inside a holding pattern. The pilot will naturally try to fly as efficiently as possible. If an aircraft can expect delays before the approach, you should try to compensate this delay beforehand by assigning a slower, more efficient airspeed. This also applies for delay vectors. Always try to reduce speeds early rather than letting an aircraft fly with a high speed on a delay track.
Resolving a Hold
In general, any instruction about lateral navigation will cancel the hold. You can give directs, vectors or simply tell the pilot to cancel the hold and continue on the Transition/STAR. If you cancel a hold close to the Approach you could give the first aircraft a vector, wait 1.5min and give the second aircraft a vector, however, that would result in variing gaps between aircraft since every aircraft will be facing a different direction when you give the instruction.
Instead it makes a lot more sense to give a few aircraft a different vector at the same time.
In this example the TSO might be the lowest aircraft but would have to turn almost 180° towards the final. Instead the most efficient way is to give the FIN the first vector. A heading of 230 for example would work fine as an intercept heading. Behind the FIN we can immediately give the same HDG to the DLH and increase the distance between FIN and DLH by using speeds or we give the DLH a heading of 210. The TSO ccan continue on its current heading for about 30-40s until it is abeam with the DLH and then we can either turn the TSO left onto the same heading as the DLH or if we want to include more delay for the TSO we can give it a heading of 190. This way all aircraft are fanning out and we can decide on the exact delay that DLH and TSO will receive depending on how long we let the DLH and the TSO fly their delay vector.
The most important point about disassembling a Hold is to never let the final be deprived of aircraft. Usually when you instruct a hold it will be because the airport is overwhelmed with aircraft. In this case you need to be as efficient as possible and always have your final filled with aircraft. If you are in doubt you should cancel holds too early rather than too late in order to maintain a high level of efficiency. You can always delay aircraft further by using delay vectors instead, but you won't be able to close a 7NM gap on final that you caused before by not cancelling the hold early enough.
VFR encounters
As a radar controller you can encounter VFR in the form of
- airspace C/D Crossing
- FIS
- IFR Cancellation
- IFR Pickup.
As a general rule the first step is always to give a squawk code and identify the aircraft. Most of these points are explained in detail in training documents in the wiki. However it should be highlighted that there is a significant difference between crossing airspace C and crossing airspace D. If you are unsure about that subject please read "Airspace Classes" from the beginning of this airticle again.
Crossing Airspace C/D overview
In airspace D everything is like in a Tower CTR. It is reasonable to give VFR aircraft a block level when crossing to allow the VFR aircraft to avoid clouds and traffic. It is important that traffic infos are given to both VFR and IFR aircraft in this case. Another option is to give Flightlevels ending with 5 such as FL85 and FL75 since the VFR aircraft will be flying inbetween typical IFR Flightlevels such as FL60, FL70 and FL80.
In airspace C there always has to be 1000ft or 3NM between VFR and IFR. If you give block levels or FL75 in this case, you would be blocking several levels at once that you cannot use for IFR. In very busy airspaces it is therefore necessary to use the same crossing levels as you would for IFR. Traffic infos are also not necessary (they are good service though) as they cannot ensure separation. Separation has to be ensured by ATC.
There should also be highlighted that there is a difference between crossing airspace C below FL100 and above FL100. Below FL100 the aircraft will always leave airspace C in one direction as the airspace will eventually end. Above FL100 the VFR aircraft will always stay in airspace C unless it is instructed to descend. That is why above FL100 it is especially important that the pilot requests a route that he/she wants to take through airspace C and when the pilot desires to descend again. The phraseology differs slightly as the following example shows.
| Crossing airspace C below FL100 | |
| "DEBIL, Piper Arrow 3, nördlich von EDDF, FL70, erbitte Durchflug durch Luftraum C über MTR und RID VOR, danach Verlassen Richtung Süden, FL70" | "DEBIL, Piper Arrow 3, north of EDDF, FL70, request crossing airspace C via MTR and RID VOR, therafter leaving to the south, FL70" |
| "(after identification)DEBIL, Duchflug genehmigt über FFM VOR, danach verlassen Sie FFM VOR auf Radial 150, FL70" | "(after identification)DEBIL, crossing approved via FFM VOR, thereafter leave FFM VOR on radial 150, FL70" |
In this case ATC was unhappy with the route and changed it deliberately. In the next example, notice that VFR above FL100 is required to be in English
| Crossing airspace C above FL100 |
| "Piper Arrow 3 Speed 120kts north of EDDF FL80, VFR to EDDS request entering airspace C and FL120 via MTR and KRH VOR, descend after KRH." |
| "DEBIL, enter airspace C, climb FL120, proceed to MTR VOR" |
FIS
Flight Information Service (FIS) is a service to the pilot by ATC providing weather information, airfield information, airspace information, traffic information and whatever the pilot might request. Always identify the aircraft first and then give the required information. The pilot will usually remain on your frequency until he/she requests to leave. In this case the pilot has to be instructed to squawk VFR and that he/she is approved to leave. If the pilot is still on your frequency when reaching your sector boundary you can instruct the pilot to contact the next station for further FIS.
Weather information is usually quite hard to come by however the QNH of the nearest airfield might be requested. Additionally the pilot might request whether a certain CTR or EDR is active or whether there is other traffic around.
General Topics
Lastly some general tips and guidelines for APP and Radar Controlling.
Having a Plan
The most common question I ask trainees during APP sims is: "what is your plan?" and in the beginning of the training process the question is usually met with silence. "A plan" usually is nothing more than deciding in which order aircraft should reach the final in order to build a good sequence. It is obvious that there is no point in having 2 aircraft reach the final at the same time since you won't have enough time to build enough separation.
Instead you should know from the very beginning which aircraft comes first, which comes second, which third and so on and you should also know how to achieve the delay that is required to turn your plan into reality. An example for this is given in the next picture. For this purpose it is assumed that aircraft on different runways need to have 4.5NM spacing when intercepting their ILS and aircraft on the same runway have to have 6.5NM spacing when intercepting. As always when working with two dependent arrival runways: Imagine that this is a single ILS and always measure from the aircraft to the ILS that the aircraft will have to fly eventually. Also it is important that the points that you measure to are abeam. Measuring to NIBAP and LEDKI for example would not work as both points are offset by a few miles.
First of all there are multiple solutions to this. You can try to come up with your own plans on how you would control this situation. Firstly, we need to decide which aircraft gets which runway. In this case the easiest solution is to have AUA on 25L and all other aircraft on 25R (if you wanted to you could also let UAL continue on present HDG and later left 070. UAL could then land on 25L). Secondly, we need to decide who comes first and for that purpose we need to know the distance of each aircraft to their ILS. The distances are as follows:
- TSO: 28.2NM
- AUA: 28.3NM
- FIN: 28.2NM+5.8NM (distance to TSO)
- UAL: 10NM+21NM+5NM (distance to fly south)
In this case it is quite difficult to let FIN come first as it first would need to gain the 5.8NM to TSO and then build up a lead over TSO of 4.5NM to ensure proper spacing. Gaining 10NM only by using speeds is practically impossible here. Therefore, we simply decide that TSO comes first, AUA comes second, FIN comes third and UAL as last. That is our plan now and everything we do now works towards our plan. Imagine if you didn't come up with a plan, then you probably wouldn't act at all and let every aircraft fly to the runway. Eventually TSO and AUA would reach the final at the same time and suddenly you would have to resolve that situation by reacting to it. On approach we don't want to react but act beforehand.
A possible solution for this whole situation would be:
- TSO gets HDG 220 as a stright in to the final with a high speed like 280kts for now.
- AUA also gets to fly to the final but not as direct. A direct HDG to LEDKI would be about 320 so instead we give HDG 340 or 350 with speed 240kts. That way if your speed is not quite enough to achieve our desired 4.5NM difference (probably won't be enough on its own, see speed calculations) we have some breathing room with the vector we gave and we can adapt the delay using this vector
- FIN can continue on the Transition for another minute then we can let her follow the TSO to the final. In order to fit the AUA between TSO and FIN we need a gap of 9NM between FIN and TSO so using speed 220-240kts for the FIN would probably work out. In order to be a little safer we can adapt the HDG for the FIN. Instead of HDG 220 we give HDG 200 or 190. That way we again use small delay vectors in case our speeds aren't quite enough.
- At the current rate UAL and FIN would reach the final at about the same time. There is no point for UAL to reach the final this early so after the previously mentioned instructions we could give UAL a slower, fuel saving speed (for example minimum clean speed), let her fly the transition and then turn her behind the FIN.
Now you know your plan and what to do in order to achieve your plan. All is left is to check your measurement and check again and check again until all aircraft are on final. You need to continue measuring to work out if your plan is working or if you need to make corrections. You need more delay? Give a greater delay vector. FIN is now exactly 9.5NM behind the TSO? Cancel the delay vector for the FIN and let her fly straight towards the final. You realize you forgot the FIN on its delay vector and now you have a 15NM gap between TSO and FIN? Use the UAL and turn her inbetween TSO and FIN. That way you stay efficient by filling a gap on your final. Always be on the look out to fill gaps on final with other aircraft.
And of course if more aircraft enter the picture, you need to come up with new plans or add these aircraft to your current plan.
Cleared Conflicts/Conflict avoidance
As a general rule you could say that you have a cleared conflict whenever two aircraft would lose their separation if they continued on their current cleared path. If they only lose their situation in 30 minutes then it is absolutely uncritical but if they are about to lose their separation within the next 5 minutes it starts to get critical. It is in your own interest to avoid cleared conflicts as much as possible since you will have to resolve them and while doing so you will have to concentrate on a single situation which might make you lose control over the rest of your airspace.
The easiest way to avoid conflicts in general is to always maintain vertical separation until two aircraft cannot possibly lose separation anymore. For example, if you have a plan like mentioned above then you can let the aircraft that is supposed to intercept first descend to the intercept altitude. The next aircraft gets intercept altitude+1000ft the next aicraft gets intercept altitude +2000ft and so on. When the first aircraft is established on the ILS, the second aircraft can descend to intercept altitude and so on. That way you avoid conflicts and even if you fell asleep for 5 minutes there still wouldn't be any conflict in your airspace.
Resolving Conflicts
Every now and then you will have conflicts in your airspace. Whether they are caused by the pilots, by you or by another ATC station, you need to resolve it. Usually conflicts can be resolved by giving climb immediately/descend immediately or by turning an aircraft 30-40° to the left or the right. Usually 30-40° is the best solution because every turn greater than 40° tends to only increase the turn radius but will not actually let you achieve lateral separation any faster.
The most important point when resolving a conflict is, to give traffic information. Always give some general information about the other traffic, it does not have to be specific. Anyhting like "traffic, A320, 12 o'clock, turn left by 30°" works fine. That is the correct way to recover from previous mistakes and that is the way you should always resolve conflicts.
Frequency Management
One overlooked aspect about approach controlling is frequency management. You simply cannot tell any aircraft to "standby" and expect it to not move any further. You will have to give an instruction eventually because traffic never stops. Overall this creates much more pressure than what you are used to on GND or TWR. Furthermore, we have discussed earlier that if you forget a turn by 30s you basically wasted one full arrival slot which can eventually cause you to lose control. Your airport might be able to handle 40 arrivals/hour but if you always waste arrival slots you will be overwhelmed with 20 arrivals/hour. Lastly, we usually occupy the whole approach of one airport. The airport might be able to handle a lot more traffic but your frequency usually can't. There are just too many instructions to give. That is why below you find tips on how to be efficient on frequency.
- Stick to standard phraseology - it is designed to be as short as possbible and as clear as possible which is why you should use it.
- Avoid triggering say agains - if you have a beginner pilot, speak slowly. If your instruction includes numbers like "contact xy on *frequency*", speak slowly - it's great if you can speak fast and gain time but it becomes absolutely useless if you spend all the gained time with answering "say agains". Also try to maintain a constant speed on frequency. it will be much easier for the pilot to follow your instruction.
- Put multiple pieces of information into one instruction - Don't just say "turn left HDG 320" but combine it with further information like "turn left HDG 320, descend 5000ft, QNH 1013". You can easily fit up to 3 instructions into a single transmission.
- Stick to only two (max three) instructions when giving the final turn - Now the exception to the rule above. Pilots tend to need longer for the readback if you give three or four instructions for the final turn. And we already established that we cannot afford to pilot to waste 20s while doing the readback because we are wasting the space on final with every second. I would recommend to stick to only two instructions for the final turn and your life will be a lot easier (e.g. turn left HDG 280, cleared ILS Runway 25).
- Use "standby" and "blocked" - these two words are the easiest way tell pilots what's going on. Standby means: Controller is busy, wait, he/she will call you back. Blocked means: You have transmitted together with another stations. You may go again after one another or the Controller will call you one by one. All this information and you spend no time saying it. Especially standby is important as it prevents the pilot from calling agian and wasting frequency time. If DLH is calling and you want to give an instruction, simply say: "Standby, SWR123, turn left HDG 320". Now DLH knows that it was heard and the Controller will respond eventually.
- Never ask a pilot if he is established on something - You can see if a pilot is established on the ILS or if he is flying the Transition. Don't ask but act when he isn't. The answer of the pilot will usually be "yes" even though the pilot is not established and you didn't gain anything but you lost precious time.
- Be calm on frequency - This is your hobby and you are doing it in your free time. If you are uneasy/pressured/triggered look for a replacement or go offline. You won't be happy, the pilots won't be happy and even worse you tend to become more difficult to understand the more uneasy you become which results in more "say agains" which will trigger you even more.
- Be friendly but decisive - This goes together with standard phraseology. If the pilots think there is a party going on on your frequency, you won't really be able to control. Through your instructions it needs to become clear that this frequency is busy and the pilots should behave accordingly. If necessary, remind them but if you stick to standard phraseology this shouldn't be necessary.
