A-CDM General
General
A-CDM is short for Airport Collaborative Decision Making. It is a concept that minimises delays and maximises efficiency by making operations more predictable for all parties involved. There are over 50 airports that implement A-CDM procedures in the real world, with more than 30 located in Europe. It works by allotting departure times to all departing aircraft, taking the airport's current capacity into account, which are calculated backwards to times for pushback and startup approvals.
On Vatsim, this A-CDM process can be simulated using the CDM plugin, although some aspects of the process are simplified for simulation purposes. Besides the airport flow control to reduce delay at the holding points, the CDM plugin is also connected to the ATFCM process of Vatsim, thus enabling network-wide flow-control management.
Usage
On Vatsim, within the EDWW FIR, the A-CDM process will be used at the following airports:
- Berlin-Brandenburg (BER/EDDB)
- Hamburg (HAM/EDDH)
ATC should always use the A-CDM procedures at EDDB and EDDH as long workload permits. The use of the A-CDM process is mandatory during (weekly) events.
Whether using the A-CDM process or not, ATC shall always adhere to the CTOTs (if present).
A-CDM Process explained
The A-CDM process is explained here.
Abbreviations
| Abbreviation | Time | Description |
| EOBT | Estimated Off-Block Time | Off-Block Time filed in the flight plan (e.g. from SimBrief). |
| TOBT | Target Off-Block Time | Time when the outbound is actually ready and would like to go off-block (submitted by the pilot via the VDGS website) |
| TSAT | Target Startup Approval Time | Time where the outbound |
|
TTOT |
Target Take-Off Time | Take-Off time based on the airport capacity. |
|
CTOT |
Calculated Take-Off Time |
Take-off time where traffic needs to depart within -5 to +10 minutes. Adhering to this time frame is mandatory. Reason: limited enroute or arrival aerodrome capacity. |