What is CDM
CDM (Collaborative Decision Making) manages the flow of departures so that runways, sectors and destination airports are not overloaded. In BIRD it is used at BIKF, BIRK, BIAR, BGGH, BGSF and EKVG.
Two parts
| Part | What it does | Who uses it |
|---|---|---|
| A-CDM (CDM plugin) | Sequences start-up at the airport. Gives each flight a TSAT from its TOBT, the departure rate and the taxi time. | DEL, GND and TWR, and APP/CTR when covering top-down |
| ATFCM (vIFF) | Issues slots (CTOTs) when a destination, sector or ECFMP measure is over capacity. | Every controller. A CTOT must always be followed. |
The CDM plugin should always be running. CTOTs are issued by vIFF whether or not anyone runs CDM at the airport.
The times
| Time | Meaning | Set by |
|---|---|---|
| EOBT | Off-block time filed in the flight plan. vIFF uses it to plan slots before the pilot connects. | Pilot (flight plan) |
| TOBT | When the aircraft will really be ready to push | Pilot on the VDGS, or ATC |
| TSAT | When start-up will be approved | CDM plugin |
| TTOT | Target take-off time: TSAT plus taxi time | CDM plugin |
| TSAC | The TSAT given to the pilot | ATC |
| ASRT | When the pilot called ready for start-up | ATC |
| ASAT | When start-up was approved | Set automatically by STUP/PUSH |
| CTOT | Slot: take-off must be within -5/+10 minutes | vIFF, or the CDM master (manual) |
Key rules
- No TOBT, no TSAT. BIRD runs CDM with real mode off: the EOBT is never copied into the TOBT. Until the pilot sets a TOBT on the VDGS or ATC sets one, the flight has no TSAT.
- Ready call: the pilot must call ready by TOBT+5. If not, the TOBT and TSAT are cancelled and a new TOBT is needed.
- Start-up is approved within TSAT ±5. Always use the TSAT in your list, not one quoted by the pilot.
- ASRT stops the flight being cancelled while it waits for its TSAT, and lets CDM look for an earlier one.
- Take-off must be within CTOT -5/+10.