Mon Aug 12, 2019 9:03 pm
Ah PHL. Its an airport that one can love and hate at the same time. PHL is considered the bastard step-child of the NYC airspace.
The northeast is a very complicated/compact airspace that sees heavy traffic load from HPN, JFK, LGA, TEB, EWR, PHL, all in a very tight 250 NM radius. These airports have arrival/departure corridors that are very tight with each other that allows you traffic to get in/out of the airports I listed. Anytime weather affects any of these corridors, the air traffic management unit will shut down the route in and out of these corridors forcing reroutes to occur with the use of an alternate corridor. This is called the Serve Weather Avoidance Program initiative aka SWAP. Keep in mind, you can only fit so many airplanes each corridor, so as a result, delays start to occur. The more routes shut down, the worst the delays start to pile on.
Depending on where you are flying too, NY center even reroute you onto what is called a low altitude escape route. It essentially, a route that is flown at a low altitude until you get can get into a different center airspace that has the spacing/workload to accept you at a higher altitude or you may be at a low altitude until you get to your destination, depends how bad storms are affecting the northeast arrival/departure corridors.
In my experience, I fly through PHL a lot as my regional has a sizeable operation there. Any time I see SWAP initiatives in effect, I am usually trying to get the reroutes with clearance delivery and our company dispatcher taken care of before leaving the gate to avoid a return to gate for fuel as I've had to return to gate before for a crazy reroute. I've also operated an LGA-ORF flight using one of the escape routes at 6,000 the entire way.
Hopefully that answers your questions.