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Roger Puig edited this page Aug 26, 2026 · 8 revisions

Calculate restrictions

Initial preperation

First, the planes are ordered by connection time. Then the priority is assigned as below:

  1. EXCLUDED
  2. SWM - Slot Wanted Message (To Keep their Slot).
  3. EVENT
  4. SIR - Slot Improvement Request.
  5. NORMAL - All other planes.

For each plane the provided OBT or EOBT (If OBT not existing) will be used as starting TTOT (OBT/EOBT + EXOT).

All calculations (Airspace Occupancy, Airspace Entries, Arrival airport and ECFMP) are triggered for each calculation. All calculations must be passed and aligned with the assigned a CTOT.

Airspace calculations

Occupancy (Occ)

In that case we will count the amount of acfts that are in the corresponding airspace for each minute of the flight. In case the resulting count is more than defined, the plane will be delayed 5 minutes and the previous counter check will be triggered again.

If this is the last applicable regulation and no ID is available for the applicable airspace, the “mostPenalisingRegulation” will be displayed with “-O” at the end indicating the reason of Occupancy.

The CTOT will be Max 3h after the initial TTOT.

Entries (E60/20)

In that case we will count the amount of acfts that are in the corresponding airspace in a time period of 20 min (00-20 / 20-40 / 40-60). In case the resulting count is more than defined, the plane will be delayed 5 minutes and the previous counter check will be triggered again. The above checks will be repeated until the counters are at or below the defined values.

If this is the last applicable regulation and no ID is available for the applicable airspace, the “mostPenalisingRegulation” will be displayed with “-E” at the end indicating the reason of Entries.

The CTOT will be Max 3h after the initial TTOT.

Destination calculations

For each airspace we make sure that between 1h before and 1h after the arrival time there are less planes than the defined arrival capacity for the arrival airport. In case of being more, then we will be increasing the ETA until we find a gap.

The CTOT will be Max 3h after the initial TTOT.

ECFMP calculations

The ECFMP uses "per_hour", "minimum_departure_interval" and "average_departure_interval" measures. For all the cases a value in minimutes is created, being the seperation in minutes between flights with the applicable restriction. In case of not complying, then we will be increasing the TTOT until we find a gap. If this had to be delayed. We will keep the CTOT and re-run the calculations again from the start with the new CTOT to make sure the new CTOT is validated for Airspace, Destination and ECFMP.

The CTOT will be Max 3h after the initial TTOT.

Final calculation

At the end, we evaluate both result:

  • If both returned a delay, the most restrictive delay is selected.
  • If only one of them returned a delay, this delay is used.
  • If none of them returns a delay and there was a previous CTOT:
    • If actual EOBT/TSAT + EXOT + 5 is already in the past, then a CTOT is created at NOW + EXOT + 5.
    • If actual EOBT/TSAT + EXOT + 5 is still in the future, then flight would not be regulated anymore (CTOT removed).
  • If none of them returns a delay, nothing happens.
  • Worst delay than previous calculations can occur in all the cases, except when "REA" is set.

Notes:

  • Planes with ATOT will NOT be taken into account to trigger a calculation but will be considered in the airspace.
  • EVENT planes will be in the top of the list (Configured by citypair in the ATM Panel dashboard) to be able to get less delays and try to avoid as much as possible restrictions.
  • Excluded planes are not entering ETFMS calculations. Meaning that they will never be affected by any regulation.

When?

Automatic complete calculations run every minute or when triggered for an specific plane by a local ACDM.

Additional regulate options

For both airports and Traffic Volumes, the following configurations are available:

Progressive Regulate: By enabling this functionallity, ETFMS system will start regulating at 80% of the maximum capacity at the destination airport or the Traffic Volume (Entries). This will create a progressive delay for the affetcted flights. Each minute delayed adds 3% capacity:

  • Minute 1: Release 3% → 83% capacity allowed
  • Minute 2: Release 3% → 86% capacity allowed
  • Minute 3: Release 3% → 89% capacity allowed
  • And so on... until 100%

Regulate Threshold: Percentage to define when the airport should start to regulate. It will be regulating with a delay 0 CTOT until the maximum capacity is exceed (Or in case "Progressive Regulate" is enabled, at 80% will start to delay) - Default is 100% (not regulating until 100%).

More information on how to activate this options: https://github.com/rpuig2001/CDM/wiki/Dashboard-Documentation#data-maintenance

DPIs

There are the following DPIs:

  • TOBT: Off Block Time (TOBT)
  • TOT: Take Off Time.
  • ATOT: Actual Take Off Time from a CDM System (Is not required, as system already sets AOBT automatically when flights are detected airborne).
  • DLA: Sends a DLA message with a new Off Blocks Time (As a difference from OBT and TOT DPIs, it does not trigger a direct ETFMS calculation for a possible CTOT).
  • SUSP: Triggers FLS-CDM Suspension.
  • REA: Flight as Ready for Improvement.
  • SIR: Slot Improvement Request - Only for exceptional which require high priority.
  • SWM: Slot Wanted Message - Fixes a CTOT for a flight (only when CTOT available).
  • EXTEND: Extends CTOT 10 minutes (Only if CTOT available and FPL already activated - ATC_ACTIV). Only possible to trigger 1 extension.
  • REQTOBT: Requested TOBT (Sets TOBT and additionally connects to the CDM Plugin to update TOBT there).
  • REQASRT: Requested ASRT (Sets ASRT and additionally connects to the CDM Plugin to update ASRT there).
  • EXCLUDED: Flight as Excluded of ATFCM measures.
  • AOBT: AOBT in ATFCM system.

Possible DPI values:

* OBT:
> Set only OBT: 'OBT/1200' (Taxi time will be default 15 in that case, if not previously provided.)
> Set OBT and EXOT: 'OBT/1100/11'.
> Remove TOBT: 'OBT/NULL'.

* TOT:
> Set only TOT: 'TOT/1200' (Taxi time will be default 15 in that case, if not previously provided.)

> Set TOT and EXOT: 'TOT/1200/11'.
> Remove TOT: 'TOT/NULL'.

* ATOT:
> Set only ATOT: 'ATOT/1200'.

* DLA:
> Send DLA: 'DLA/1200'.

* SUSP:
> Set: 'SUSP'.

* REA:
> Set: 'REA/1'.
> Remove: 'REA/0'

* SIR:
> Set: 'SIR/1'.
> Remove: 'SIR/0'

* SWM:
> Set: 'SWM/1'.
> Remove: 'SWM/0'

* EXTEND:
> Set: 'EXTEND/1'.

* REQTOBT:
> Set tobt 1533 from pilot: 'REQTOBT/1533/PILOT'.
> Set tobt 1533 from ATC: 'REQTOBT/1533/ATC'.
> Clear tobt and type: 'REQTOBT/NULL/NULL'.

* REQASRT:
> Set asrt 1533: 'REQASRT/1533'.
> Clear asrt 'REQASRT/NULL.

* EXCLUDED:
> Set: 'EXCLUDED/1'.
> Remove: 'EXCLUDED/0'

* AOBT:
> Set: 'AOBT/1642'.
> Clear: 'AOBT/NULL'

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