Re-routes from clearance delivery

[floats4fun]

How do these work? Is it all automated? Does a computer take your filed route, determines it wont work with the flow of traffic, and some matrix notifies the controlling agency (clearance) it won't jive with surrounding controlling agencies (or busy routes) and spits out a more economic route for clearance delivery to give to the pilots? I guess my question is, who is the person who ultimately says "no this flight planned route won't work for this routing, it must be changed" or is it all computers doing the changing now.

Also, when My flight plan goes MIA and clearance says they will check with the flight planning department, what do these guys/girls do? I assume it's a legitimate statement and not a joke as sometimes it can take a while for ATC to get back with a response on a flight plan that may have gone missing or not filed correctly.

Thanks!

[CpnCrunch]

Not an answer to your question, but sometimes you get "flight planned route" from clearance delivery and they then give you a different routing when you're actually in the air and tell you "you'll never get that route that you filed". From that I assume that they don't actually check the route all that carefully when you plan it.

I think you just need to be thankful you're not flying IFR in Europe:

http://www.peter2000.co.uk/aviation/ifr-flying/

[ahramin]

There is a flight plan department at the ACC that deals with flight plans. If the compiter can process the flight plan automatically, it does. Otherwise the humans deal with it. In the case of a rejected route, I would imagine a human does that but I couldn't say for sure.

[cossack]

Preferential routes between airports are published in the CAP. File one of those and 99% of the time when you call Clearance that's what you'll get. File something different and it gets accepted by Ottawa, sent to the ACC and modified usually before Clearance sees it. Clearance then has to read the new route either in full (PITA) our just part of it if only minor modification was required near the start. i.e. wrong SID filed.

Other times when you may have filed the correct route and it gets changed is usually for traffic management (Flow) to avoid weather or busy airspace. This may be last minute, follow a ground stop or be planned in advance but not picked up at time of filing.

In Canada I don't think its automated. There is still someone in the ACC's flight planning office manually checking and amending flight plans. When Clearance says they'll call flight planning, that's exactly what they'll do. Usually when they say that 5 other guys call for clearance at the same time. I'm on the phone!

[floats4fun]

Thanks Cossack!

[linecrew]

Preferential routes between airports are published in the CAP.

Slight correction; they're actually in the CFS Planning section (part C), not the CAP.

[cossack]

Thanks for the correction. They're in one of the thick books on Clearance's desk.