Weather & capacity
Bad weather lowers how many aircraft an airport can handle. Use CDM measures only when demand is higher than the reduced capacity.
1. Check demand 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 vIFF Flight List.
2. Departures: LVO rate
- Each airport has a normal and an LVO departure rate (see Airport CDM data). Switch with
.cdm lvo. - Use the LVO rate only when low-visibility procedures are in force. Strong wind or a low cloud base alone is not LVO.
- If conditions need extra spacing without LVO, agree it with the CDM master.
.cdm departuredelaycan hold departures for a period.
3. Arrivals: arrival regulation
- On the vIFF dashboard, add a restriction on the airport (type ARR) with a lower rate for a set period. vIFF then gives CTOTs to inbound flights.
- A CTOT only holds a flight on the ground if its departure airport follows vIFF slots. Much long-haul traffic into BIKF will not be held.
- So at BIKF a regulation helps only partly. You will still need holding, miles-in-trail or minutes-in-trail from adjacent centres (Gander, Shanwick, Scottish, Bodø) and speed control.
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 10, about 22 kt crosswind gusting 28, single-runway operations.
- 700 ft cloud and 4 km visibility is not LVO. Keep the normal departure rate.
- Realistic arrival capacity is about 15–18 per hour, down from 26.
- Fewer than about 15 arrivals expected: no regulation needed.
- Arrivals bunching above that: set a BIKF arrival restriction of about 16 per hour for the affected period, and use holding or in-trail spacing for flights without CTOTs.
6. Who decides
The CDM master and the APP/CTR controller decide on LVO rates and arrival restrictions. Tell adjacent units when a restriction is in force.