Weather & capacity

Bad weather reduceslowers how many aircraft an airport can handle. This page explains which CDM tools help, and when.

First: check demand

Only useUse CDM measures only when demand is higher than the reduced capacity.capacity.

If

1. trafficCheck isdemand light,first

• In light traffic, bad weather alone is not a reason to regulate. Normal spacing, holding and coordination are enough.

• Check expected flights per hour in the arrival and departure lists, or in the CDMvIFF dashboard,Flight forList.
how many flights are expected per hour.

2. Departures: LVO rate

• Each airport has a normal and aan low-visibility (LVO)LVO departure rate.rate See(see Airport CDM data).
  Switch with .cdm lvo.
  • Use the LVO rate only when low-visibility procedures are in force.
  force.
  • Strong wind, gustswind or a low cloud base alone dois not meanLVO.
  LVO.
  • If departuresconditions need extra spacing inwithout those conditions,LVO, agree it with the CDM master. .cdm departuredelay can hold departures for a period.

  3. Arrivals: arrival regulation

  If

  more
  • On arrivalsthe arevIFF expecteddashboard, thanadd a restriction on the airport can(type take,ARR) anwith arrivala regulation can be set on the CDM dashboard by lowering the airport's arrivallower rate for a timeset period. The CDM servervIFF then gives CTOTs to inbound flights.

  Arrival

  • A regulationsCTOT only giveholds CTOTsa toflight flightson departingthe fromground airportsif usingits CDM.departure Mostairport follows vIFF slots. Much long-haul traffic into BIKF (North America, much of Europe) departs from airports without CDM and will not be heldheld.
  on
  • So the ground.

    Forat BIKF this means an arrivala regulation helps aonly little,partly. but youYou will still need:

    need
    holding,
    • Holding
    • Miles-miles-in-trail or minutes-in-trail requested from the adjacent centrecentres (Gander, Shanwick, Scottish, Bodø,Bodø) etc.)
    and
    • Speedspeed control on arrivalcontrol.

    Example:4. Booking-based scenarios

    vIFF also lowers BIKF capacity automatically depending on which positions are booked. Scenario changes are posted in the vIFF Discord #flow-log channel. Book your position so the right scenario applies.

    Booked	Scenario	BIKF arrivals/hr	BIKF departures/hr	Approach entries/hr	Approach occupancy
    BIKF APP only	BI-BIKFTD	10	10	20	6
    BIKF APP + TWR, no CTR	BI-APPONLY	14	16	30	10
    BIKF APP + any BIRD CTR	BI-APPENR	14	16	30	10
    Any BIRD CTR, no BIKF APP	BI-ENRONLY	10	10	20	6

    5. Worked example: BIKF in strong crosswind

    BIKF 14036G46KT 4000 DZRA BR OVC007 08/08 Q1005

    • Runway 1010, is best for this wind (about 22 kt crosswind,crosswind gusting 28).28, Single single-runway operations.
    • A 700 ft cloud base withand 4 km visibility is not LVO. Keep the normal departure rate.
    • Realistic arrival capacity is about 15–18 per hourhour, insteaddown offrom 26.
    • If fewerFewer than about 15 arrivals per hour are expected: no regulation needed.
    • If arrivals startArrivals bunching above that: set ana BIKF arrival regulation for BIKFrestriction of about 16 per hour on the dashboard for the affected period, and use holding or in-trail spacing for flights without CTOTs.

    6. Who decides?decides

    The CDM master,master together withand the APP/CTR controller,controller decidesdecide on LVO rates and arrival regulations.restrictions. Inform theTell adjacent units when a regulationrestriction is in force.