IFR Low Altitude - Preferred Routes Vs Auto-Routing

Devil07

Rookie
Jul 14, 2018
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I asked this question on pilot boards and no one seems to know anything about this. My question is about the difference between "preferred routes" and "auto-routes" that are provided by flight planning software. Specifically, when a destination has "no preferred routes" the software offers me an "auto-routing" route (sometimes its silly), but it seems to be based on an algorithm of nearest VOR/Intersection/Victor Airway to destination.

Confession: I'm just now starting to use these online resources for IFR flying. I used to just do it by hand on paper charts and call it in, but I really like to have an idea of what ATC would like because if it matches up with what I need, then its a win-win.

QUESTION: If a destination has "No Preferred Routes", and all I'm provided with is "auto-routing" what is the likelihood of getting a "cleared as filed" if I file "Direct" vs using the "Auto-Routing" route?

I looked at a couple of routes on fltplan.com and noticed that the "auto-routing" was not even in the 5 Most Recent Planned ATC routes, so it seems like they aren't used often. Almost seems like the auto-routing is not preferred by anybody (pilots or controllers). For example, on a short 79 mile flight, the auto-routing suggests flying on 3 different victor airways. NOTE: I'm flying to out of the way airports in midwest, not congested airspace at all, most don't even have SIDs or STARs.
 

Stinger

Epic Member
May 24, 2009
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You're likely not going to have a good idea of which routes to expect until you fly 3-4 times between the same two airports.
If there's "no preferred routes" and the "auto-route" doesn't make a whole lot of sense, your chances of getting a direct clearance would be fairly high.
 

Devil07

Rookie
Jul 14, 2018
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@stinger that makes a lot of sense to me, especially in the low congestion areas where I fly. I assume direct routing makes the controller's life easier too. In one of the examples I was looking at, direct routing took me from a small Class D through rural flat land to another Class D, but the auto-routing, took me like 25 miles out of the way through/over Class C, just because thats where the Victor airway was. I guess auto-routing is designed with traditional /U aircraft in mind.