Thread: EDC vs. Release Time
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Old 09-16-2009 | 01:50 PM
  #15  
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Bubba
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From: Crew Lounge Recliner
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If I could just expand on winglet’s post… pretty much spot on. EDCT’s are a national ground delay program from the ATCSCC, in the old days it was called Central Flow Control. They are looking at the major “pacing” airports, ATL ORD LAX SFO JFK LGA EWR… There is this formula that looks at airport arrival rates based on runway configuration, weather, airport acceptance rate, strings and mirrors, done in the dark with nobody looking, mathematical model stuff that’s put into a computer that generates EDCT’s based on your “proposed departure time”, and your predicted arrival time. 121 guys have no say to the departure time, but here’s a tip to you non-sched and Part 135 guys…. http://www.fly.faa.gov/flyfaa/usmap.jsp You see that ORD/EWR/LAX is running a 2 hour delays, the big cheese in back wants to depart BFE (Bum F-ck Egypt) at 9:00 am, File a 7:00 am departure so the EDCT will issue you a 9:00 am EDCT! Too easy!
Now, let’s say that you are going from SYR to ORD, there is wx, yadda, yadda, and you have an EDCT time of 9:05 based on your “proposed” departure time of 7:30. All of this information was relayed to you at 7:05 as your FO dutifully called SYR clearance delivery for a clearance to ORD (clearances are available 30 prior to your proposed departure time). At 8:55 you are calling ground control for a push back/taxi clearance to make your 9:05 EDCT. Ground control informs you that you have a “9:15 release time”. ***?
EDCT’s are based on PFM, some sort of computer program, but for your “release time”, SYR tower is going to call the Center (in this case Cleveland Center’s Traffic Management Unit) and tell them that you will be ready to depart at 9:05, what time can you be released? ClevelandCenter is going to look at the actual aircraft in the air and try to wedge you into the conga line headed into ORD via the PAITN arrival as you depart SYR. Release times are going to be based on the actual number of aircraft in the air, and a “guestimation” that you’ll fit.
Release times have nothing to do with EDCT’s. For example let’s say that Denver Center has to give LA Center 15 miles between aircraft headed to LAX over CIVET, there are no national ground delay programs out there (EDCT’s, think FAA Washington, DC; release times are generated at your local Air Route Traffic Control Centers) Denver Center’s Traffic Management Unit will issue “release times” for LAX bound traffic from airports within Denver Center.
The intent is to keep a load on the system, not a burden. If ORD says they have an airport acceptance rate of 90, you want aircraft over the arrival fixes to meet that arrival rate… Hub and spoke be dammed, only so many aircraft can occupy the same piece of concrete at the same time. All others spin.
This concludes part one: Part two, The ugly truth.
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