ATC Positions
Each ATC position handles a specific part of your flight. Controllers log in with a callsign that includes a suffix indicating their position.| Position | Suffix | Typical Frequency | Responsibilities |
|---|---|---|---|
| Delivery | _DEL | 121.x | Issues IFR clearances, assigns squawk codes and initial altitude |
| Ground | _GND | 121.6 - 121.9 | Pushback approval, taxi instructions, gate assignments |
| Tower | _TWR | 118.x - 119.x | Runway operations, takeoff and landing clearances |
| Approach / Departure | _APP / _DEP | 119.x - 135.x | Terminal area radar control, vectors, approach clearances, initial climb |
| Center (En Route) | _CTR | 128.x - 135.x | Cruise altitude control, en route separation, flight level changes |
On VATSIM, you can identify which controller to contact by looking at the controller list in your pilot client. It shows each online controller’s position, callsign, frequency, and the area they cover.
How the Positions Work Together
In a fully staffed scenario, you move through ATC positions in this order:Top-Down Coverage
On VATSIM, you will rarely find every position staffed at an airport. Top-down coverage is the principle that a controller covering a higher-level position also handles all lower positions within their airspace. Here is how it works:| If Only This Is Online | They Also Cover |
|---|---|
| Center (_CTR) | Approach, Tower, Ground, and Delivery for airports in their sector |
| Approach (_APP) | Tower, Ground, and Delivery for the airport(s) they cover |
| Tower (_TWR) | Ground and Delivery for their airport |
| Ground (_GND) | Delivery for their airport |
| Delivery (_DEL) | Delivery only |
Practical Example
If you are departing Toronto and only Toronto Center (CZYZ_CTR) is online:- Contact Center on their frequency for your IFR clearance
- Contact the same controller for pushback and taxi
- Contact the same controller when ready for departure
- The controller handles your entire flight until you leave their sector or they hand you to another controller
Handoff Procedures
A handoff is when one controller transfers you to another. This happens at the boundary between controller areas of responsibility.Standard Handoff
Then on the new frequency:“Monitor” vs “Contact”
This distinction is critical and catches many new pilots off guard:| Instruction | Action |
|---|---|
| ”Contact [position] [frequency]“ | Tune the frequency and call them with a check-in |
| ”Monitor [position] [frequency]“ | Tune the frequency but do not call. Wait for them to call you. |
Squawk Codes
Your transponder squawk code identifies your aircraft on ATC radar. ATC assigns you a unique squawk code during your IFR clearance.Standard Codes
| Code | Meaning |
|---|---|
| Assigned code (e.g., 4521) | Your unique identifier, assigned by ATC during clearance |
| 2000 | Default IFR code (used when no specific code has been assigned yet) |
| 1200 | VFR (visual flight rules) - used when flying VFR without ATC services |
| 7500 | Hijack |
| 7600 | Communication failure (lost comms) |
| 7700 | Emergency |
Setting Your Squawk Code
- ATC assigns your squawk code during the IFR clearance (e.g., “Squawk 4521”)
- Enter the code in your transponder panel
- Set your transponder to Mode C (altitude reporting) - this is the standard setting for IFR flights
- ATC will see your callsign and altitude on their radar scope
When ATC Goes Offline
Controllers on VATSIM are volunteers and may disconnect at any time - their session ended, real life called, or their shift is over. Here is what to do:Complete Scenario Walkthroughs
Full ATC Staffing (DEL, GND, TWR, DEP, CTR, APP, TWR, GND)
Full ATC Staffing (DEL, GND, TWR, DEP, CTR, APP, TWR, GND)
This is the ideal scenario with every position staffed. Here is the complete flow from gate to gate.Departure - Toronto (CYYZ)Step 1: ATIS - Tune ATIS on COM2. Note the information letter (e.g., Bravo), runway, and altimeter.Step 2: Delivery (CYYZ_DEL) - Request IFR clearance on COM1.Step 3: Ground (CYYZ_GND on 121.9) - Request pushback and taxi.Step 4: Tower (CYYZ_TWR on 118.7) - Hold short, then get takeoff clearance.Step 5: Departure (CYYZ_DEP on 126.4) - Climb out of the terminal area.Step 6: Center (CZUL_CTR on 132.2) - Cruise at altitude.Arrival - Montreal (CYUL)Step 7: Approach (CYUL_APP on 119.1) - Descent and vectors.Step 8: Tower (CYUL_TWR on 118.9) - Landing clearance.Step 9: Ground (CYUL_GND on 121.9) - Taxi to gate.
Only Center Online (Top-Down Coverage)
Only Center Online (Top-Down Coverage)
This is the most common scenario on VATSIM. A single Center controller handles everything for airports in their sector.Departure - Toronto (CYYZ) with only CZYZ_CTR onlineStep 1: ATIS - Check if ATIS is available. If not, the Center controller may provide airport conditions.Step 2: Contact Center for clearance, pushback, and taxi.Step 3: When ready, report back to Center for taxi and departure.Step 4: En route - continue on the same frequency. Center already has you.Step 5: Arrival - Center provides approach instructions.
When a Center controller is providing top-down service, they may combine instructions to keep things efficient. You might receive your approach clearance and landing clearance in fewer exchanges than with full staffing.
No ATC Online (UNICOM Only)
No ATC Online (UNICOM Only)
When no controllers are online anywhere along your route, you fly on UNICOM (122.800) and self-announce.Departure - Toronto (CYYZ) on UNICOMEn route - Position reports are optional but helpful if there is traffic nearby.Arrival - Montreal (CYUL) on UNICOM
Etiquette and Tips
ATC controllers on VATSIM are unpaid volunteers. They are providing a service because they enjoy it and want to create a realistic experience for everyone. Always be respectful, patient, and courteous - even when things get busy or mistakes happen.
- Be patient during busy periods. Controllers may have 10 or more aircraft to manage. If they do not respond immediately, wait. They will get to you.
- Do not repeat your call unless at least 30 seconds have passed without acknowledgment. Controllers are likely working other aircraft.
- Follow instructions promptly. If you need time (e.g., to reprogram your FMS), say “Standby” and get back to them quickly.
- If you make a mistake, say “Correction” and fix it. Do not dwell on errors - just correct and move on.
- Thank the controllers when you finish your flight. A simple “Thanks for the service, good day” goes a long way.
Next Steps
Radio Phraseology
Complete reference for standard radio calls at every phase of flight
Voice Basics
Understand frequencies, UNICOM, ATIS, and Audio for VATSIM