Pilot guide: VDGS & CDM
Departing from BIKF, BIRK, BIAR, BGGH, BGSF or EKVG? These airports use CDM (Collaborative Decision Making) to give every flight a fair start-up time and avoid queues at the runway.
The short version
- File your flight plan with a realistic off-block time (EOBT). Flow management uses it to plan your slot before you connect.
- Once on board, go to vats.im/vdgs and confirm or update your TOBT: the time you expect to be ready for push and start.
- Call Delivery for your clearance. You will get a TSAT (start-up time), and a CTOT (slot) if your flight is regulated.
- Call ready for start-up no later than 5 minutes after your TOBT. Start-up is approved within ±5 minutes of your TSAT.
The times
| Time | Meaning | Who sets it |
|---|---|---|
| EOBT | Estimated off-block time, from your flight plan | You, in the flight plan |
| TOBT | Target off-block time: when you will be ready to push | You, on the VDGS (or ATC on first contact) |
| TSAT | Target start-up approval time: when ATC will approve your start-up | The CDM system |
| CTOT | Calculated take-off time (slot): you must take off within -5/+10 minutes | Flow management |
On frequency
If you have not set a TOBT on the VDGS, Delivery will ask for one before giving your clearance:
ATC: "ICE123, report your target off-block time."
Pilot: "Target off-block 1420, ICE123."
Your clearance ends with your slot (if you have one) and your start-up time:
"ICE123, cleared to London Heathrow via DELES2C departure, runway 19, squawk 2341. Slot 1450, expect start-up at 1435, call ready for start-up."
Read back the slot and start-up time with the rest of the clearance.
Good to know
- Your TSAT can change until start-up is approved. Check the VDGS before you call.
- If you call for start-up earlier than TSAT-5, you will be asked to wait.
- If you are ready earlier than your TOBT, update it on the VDGS. You may get an earlier TSAT.
- If you are running late, update your TOBT as soon as you know. This frees your slot for someone else.
- If you have not called ready by 5 minutes after your TOBT, or your TSAT expires, your times are cancelled and you must give a new TOBT.
- If you have a CTOT, plan your start-up and taxi so you can take off within -5/+10 minutes of it.
- If you are going to miss your CTOT, tell ATC as early as possible. ATC can extend it once by 10 minutes; otherwise you will get a new slot, which may be much later.
- Using SimBrief? The vIFF for SimBrief browser extension shows your CTOT alongside your flight plan.
Confirming your TOBT on the VDGS is not mandatory, but it is the best way to avoid long delays. If you do not, Delivery will ask for your TOBT when you call for clearance.