Weather & capacity

Bad weather reduces how many aircraft an airport can handle. This page explains which CDM tools help, and when. 
 First: check demand 
 Only use CDM measures when demand is higher than the reduced capacity . If traffic is light, bad weather alone is not a reason to regulate. Normal spacing, holding and coordination are enough. 
 Check the arrival and departure lists, or the CDM dashboard, for how many flights are expected per hour. 
 Departures: LVO rate 
 Each airport has a normal and a low-visibility (LVO) departure rate. See Airport CDM data . 
 
 Use the LVO rate only when low-visibility procedures are in force . 
 Strong wind, gusts or a low cloud base alone do not mean LVO. If departures need extra spacing in those conditions, agree it with the master. 
 
 Arrivals: arrival regulation 
 If more arrivals are expected than the airport can take, an arrival regulation can be set on the CDM dashboard by lowering the airport's arrival rate for a time period. The CDM server then gives CTOTs to inbound flights. 
 Arrival regulations only give CTOTs to flights departing from airports using CDM . Most long-haul traffic into BIKF (North America, much of Europe) departs from airports without CDM and will not be held on the ground. 
 For BIKF this means an arrival regulation helps a little, but you will still need: 
 
 Holding 
 Miles-in-trail or minutes-in-trail requested from the adjacent centre (Gander, Shanwick, Scottish, Bodø, etc.) 
 Speed control on arrival 
 
 Example: BIKF in strong crosswind 
 BIKF 14036G46KT 4000 DZRA BR OVC007 08/08 Q1005 
 
 Runway 10 is best for this wind (about 22 kt crosswind, gusting 28). Single runway operations. 
 A 700 ft cloud base with 4 km visibility is not LVO. Keep the normal departure rate. 
 Realistic arrival capacity is about 15–18 per hour instead of 26. 
 If fewer than about 15 arrivals per hour are expected: no regulation needed. 
 If arrivals start bunching above that: set an arrival regulation for BIKF of about 16 per hour on the dashboard for the affected period, and use holding or in-trail spacing for flights without CTOTs. 
 
 Who decides? 
 The CDM master, together with the APP/CTR controller, decides on LVO rates and arrival regulations. Inform the adjacent units when a regulation is in force.