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Controllers Guide - CDM

This guide covers how BIRD controllers run departures with the CDM plugin and handle slots (CTOTs) issued by vIFF. It applies to BIKF, BIRK, BIAR, EKVG, BGGH and BGSF.

  • CDM sequences start-up locally. From each TOBT it calculates a TSAT (start-up time) and TTOT (take-off time) using the airport's departure rate.
  • vIFF is the network flow system. It issues CTOTs when an airport, a Traffic Volume or an ECFMP measure is over capacity. CTOTs exist whether or not CDM is running.

The BIRD install pack runs CDM with real mode off. The filed EOBT is never copied into the TOBT, so a flight has no TOBT, TSAT or TTOT until the pilot sets one on the VDGS or DEL sets it. Getting the TOBT is part of every clearance.

The times

TimeMeaningSet by
EOBTOff-block time filed in the flight planPilot
TOBTWhen the aircraft will really be ready to pushPilot (VDGS) or DEL
TSATWhen start-up will be approvedPlugin
TTOTTSAT plus taxi timePlugin
ASRTWhen the pilot called ready (RSTUP)DEL/GND
CTOTSlot from vIFF, or a manual slotvIFF or CDM master
CTOCThe CTOT passed to the pilot, and how far the live CTOT has moved sinceDEL
  • TSAT is valid ±5 minutes.
  • CTOT is valid -5/+10 minutes.
  • No ASRT/RSTUP by TOBT+5: the plugin cancels the TSAT and a new TOBT is needed.

Before you connect

  1. Use the current BIRD install pack. It includes CDM.dll, CDMconfig.xml, rate.txt and taxizones.txt. Do not replace these files with your own.
  2. Make sure the CDM plugin is loaded and allowed on your display (OTHER SET → Plug-ins).
  3. Use the departure list from the profile, with the CDM columns: EOBT, TOBT, TSAT, ASRT, RSTUP, TTOT, CTOT, CTOC, NSTS and Flow Message.
  4. Book your position on the VATSIM booking system. vIFF scenarios only see bookings, not who is online.

Starting a session

The lowest position at the airport is CDM master: DEL, otherwise GND, otherwise TWR or the top-down controller. Everyone else runs as slave.

  1. Select the active departure runways in the Runway dialog. With no runway selected, CDM calculates nothing.
  2. Type .cdm master BIKF (or your airport's ICAO).
  3. Check the CDM panel (.cdm panel): green = you are master, purple = someone else is (coordinate first), red = no master.
  4. Times update every 10 seconds. If they do not appear, type .cdm refresh.

Handover and logging off

  1. Outgoing master types .cdm slave.
  2. Incoming controller types .cdm master BIKF.
  3. After a EuroScope crash, reconnect and type .cdm recover BIKF.

Delivery

  1. On first contact, check the TOBT column:
    • TOBT set on the VDGS and still valid: use it.
    • No TOBT, or clearly wrong: ask for one, then enter it with TOBT Options → Edit TOBT.
    • Pilot ready now: use Ready TOBT. This sets TOBT to now and asks vIFF for a better slot (REA).
  2. Wait for TSAT and TTOT to appear (up to 10 seconds).
  3. Check the CTOT column. If there is a CTOT, the Flow Message shows the regulation causing it.
  4. Give the clearance, ending with the start-up time and the slot time if there is one.
  5. If there is a CTOT, click CTOC → Add CTOT to CTOC to record what you passed to the pilot.
  6. When the pilot calls ready, click RSTUP, then transfer to Ground within TSAT ±5.

Phraseology

No TOBT:

DEL: "ICE123, report your target off-block time."
Pilot: "Target off-block 1420, ICE123."

If the pilot does not know the term: "ICE123, when will you be ready to push back?"

Clearance, no CTOT:

"ICE123, cleared to London Heathrow via DELES2C departure, runway 19, squawk 2341. Start-up time 1425, call ready for start-up."

Clearance with CTOT:

"ICE123, cleared to London Heathrow via DELES2C departure, runway 19, squawk 2341. Slot time 1450, start-up time 1435, call ready for start-up."

Ready too early:

"ICE123, start-up time 1435, stand by on this frequency."

Transfer:

"ICE123, contact Keflavík Ground 121.900."

During events with a slot file, the slot appears in the EvSlot column. Click Add Event CTOT as MAN CTOT to apply it.

Ground

  1. Approve push and start within TSAT ±5, and set the ground status so ASAT is recorded.
  2. Pilot calls before TSAT-5: "start-up time 1435, stand by."
  3. Pilot calls after TSAT+5 with no RSTUP: send them back to Delivery for a new TOBT.
  4. With a CTOT, time the taxi so the aircraft reaches the holding point inside the slot window, not early.

Tower

  1. Take-off must be within CTOT -5/+10. Check the CTOT column before line-up.
  2. If an MDI is active, keep the interval between airborne times. You may clear an aircraft slightly early to meet it.
  3. During radar release periods, get an APP release for each departure before take-off clearance.

Missed slots

SituationAction
Will miss by a few minutes, flight plan activeCTOT Options → EXTEND (+10 minutes, once only)
Will miss by moreSend REA (Network Sts) for a new slot; coordinate with DEL
Manual slotCDM master sets a new manual CTOT
CTOC turns redThe live CTOT is more than 5 minutes later than the one given. Pass the new slot to the pilot.

Where slots come from

  • BIRD scenarios: switched on automatically from VATSIM bookings, posted in the vIFF #flow-log channel.
  • Destination arrival rates: when the destination is over capacity.
  • ECFMP measures: per-hour, MDI and ADI measures are included automatically.
  • Manual CTOT: CTOT Options → Set/Remove MANUAL CTOT. Only accepted when the TSAT is more than 5 minutes away.
BookedScenarioBIKF ARR/hrBIKF DEP/hrApproach entries/hrApproach occupancy
BIKF APP onlyBI-BIKFTD1010206
BIKF APP + TWR, no CTRBI-APPONLY14163010
BIKF APP + any BIRD CTRBI-APPENR14163010
Any BIRD CTR, no BIKF APPBI-ENRONLY1010206

Useful commands

CommandUse
.cdm master BIKF / .cdm slaveTake or release CDM master
.cdm refreshForce a recalculation
.cdm lvoSwitch to the low-visibility departure rate
.cdm startupdelay BIKF/19 1900Hold all TSATs on a runway until 1900 (9999 clears it)
.cdm departuredelay BIKF/19 1900Hold all TTOTs on a runway until 1900 (9999 clears it)
.cdm recover BIKFRestore times after a crash
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