Traffic Flow Management (TFM)

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Severe Weather Avoidance Program (SWAP)

SWAP is a formalized program that is developed for areas susceptible to disruption in air traffic flows, caused by thunderstorms. Each air traffic facility may develop its own strategy for managing the severe weather event. Their plan then becomes part of the overall daily operations plan.

Since each weather event is unique, the response is tailored to meet the specific forecasted and actual events of the day. The SWAP plan is issued through the Planning Telcon. The plan, available to all users, is published as an advisory after the telcon. Additionally, routes issued in support of SWAP are issued as route advisories by the ATCSCC. They may be found at

The best way to respond to SWAP, once it has been implemented, is to be informed about conditions in the NAS and plan appropriately. Be prepared to respond to rapidly changing weather conditions which may require new routes, often longer, to be issued. ATC may request flights to evaluate flight conditions after the weather has passed. If a flight is capable, it is encouraged that they volunteer their services.

The question is often asked, "Why do I get delayed on the ground when the weather is VFR?". The answer is that there may be times when the weather enroute or at your destination airport is what prevents the departure, rather than the weather at the departure airport. If aircraft are all deviating through a small opening in the weather, traffic flow becomes very condensed and complex, thereby requiring additional traffic management initiatives.

On the other hand, if the destination airport has a reduced airport arrival rate (AAR) for some reason, a flight may be delayed because of TMIs or compliance with a GDP.

The best advice is to pay attention to what is being said on the radio and be informed.