How does ForeFlight get 'expected route clearance'?

Fearless Tower

Fearless Tower

Touchdown! Greaser!
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Fearless Tower
So, when I first started filing IFR though FF, I found the 'expected route clearance' to be pretty handy. Often, it would include minor ATC adjustments to my filed route and would be the same clearance that Clearance Delivery would give me.

Recently (last month or so) I noticed an odd trend: every time I have filed IFR, I receive an 'expected route clearance' that is exactly what I filed. Funny thing is, that when I call up CD for my clearance, they have a different routing.

Where is FF getting the expected routing and why is it not correct?
 
It is a service provided by a number of vendors, including LockMart itself. It actually is the "expected" clearance, subject to change. Others' know far more than I do, but the essence is that clearances are created by computer that works on a national level, subject to change at the local level at the time of delivery based on actual conditions.

The degree to which what you expect is what you do or don't get seems to depend a lot on geographic location. In super-busy airspace there are a lot of things to change the overall picture on short notice. In more quiet areas, less so. For example, you seem to be getting a lot of "wrong" expected clearances. OTOH, (much) better than 90° of the ones I get are spot-on. I think the last time one was "wrong" was leaving an airport near a restricted area. I filed and received an "expected" clearance to go around the restricted area. But when I called for my actual clearance, I was given direct through it since it wasn't in use at the time.

Why you were getting "correct" ones and suddenly started getting "wrong" ones is something I couldn't begin to answer.
 
I don't know the digital nuts and bolts of how FF and LMFS determine those expected routes, but based on what knowledge I have of the ATC system, what midlife flyer says makes a lot of sense. Where do you fly out of Fearless? Did you notice other things happening differently around there a month or so ago when you noticed this change? Any MOA's being active a lot that didn't use to be? Why don't you file a "no way in the world I'll get this route" flight plan and see if it gives you that "expected route"
 
luvflyin said:
I don't know the digital nuts and bolts of how FF and LMFS determine those expected routes, but based on what knowledge I have of the ATC system, what midlife flyer says makes a lot of sense. Where do you fly out of Fearless? Did you notice other things happening differently around there a month or so ago when you noticed this change? Any MOA's being active a lot that didn't use to be? Why don't you file a "no way in the world I'll get this route" flight plan and see if it gives you that "expected route"
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I fly out of ORF and the last couple weeks have made a couple trips back and forth between Norfolk and Brunswick ME. I've noticed this on both ends. FF will tell me my expected routing is exactly what I filed and then I will get a different route when I call up for the clearance. Leaving ORF the difference tends to be relatively minor (add a couple of GPS waypoints to get me to the filed airway). That makes sense based on what Mark suggested. Leaving Maine, the clearance I get from ATC is nothing like what I filed or was given in the expected route.
 
luvflyin said:
I don't know the digital nuts and bolts of how FF and LMFS determine those expected routes, but based on what knowledge I have of the ATC system, what midlife flyer says makes a lot of sense. Where do you fly out of Fearless? Did you notice other things happening differently around there a month or so ago when you noticed this change? Any MOA's being active a lot that didn't use to be? Why don't you file a "no way in the world I'll get this route" flight plan and see if it gives you that "expected route"
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...and where are you heading?

@Fearless Tower, just saw your post. Given that Norfolk to Maine is to the north, including both the DC and NY areas, I would not be surprised to see a discrepancy between expected and cleared.

But I have another possibility to look at. Are you using the "Routes" function in ForeFlight to choose what you file? If so, I think that has been a FF weakness when compared with sites like FltPlan.com when it comes to reality. I've seen a number of situations in which FF defaults to a pure airway routing, which will be fine with the computers that "approve" expected "Center" routes, but have no relation to the real "TRACON" routes ATC assigns through areas like that.
 
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Here's what FltPlan.com shows as the two most recently cleared routes between KORF and KBXM. Skyvector also shows these.

SCHOL DUNFE V139 HTO MHT ENE
CCV V139 SIE V44 DPK MHT ENE

Either of those closer to what you are actually getting. (I haven't compared with FF)

Edit: Never mind, I wouldn't file or accept either of those routes, but it may help explain the problem.
 
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ForeFlight gets the expected route from FlightAware. This is usually generated by the ATC computer. The local facility or flow control can modify the route after it is initially generated. The modified route is not obtained by ForeFlight, so it can be different.
 
midlifeflyer said:
Here's what FltPlan.com shows as the two most recently cleared routes between KORF and KBXM. Skyvector also shows these.

SCHOL DUNFE V139 HTO MHT ENE
CCV V139 SIE V44 DPK MHT ENE

Either of those closer to what you are actually getting. (I haven't compared with FF)

Edit: Never mind, I wouldn't file or accept either of those routes, but it may help explain the problem.
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FF has the same recent routes. Also has an all airway route.
 
midlifeflyer said:
Here's what FltPlan.com shows as the two most recently cleared routes between KORF and KBXM. Skyvector also shows these.

SCHOL DUNFE V139 HTO MHT ENE
CCV V139 SIE V44 DPK MHT ENE

Either of those closer to what you are actually getting. (I haven't compared with FF)

Edit: Never mind, I wouldn't file or accept either of those routes, but it may help explain the problem.
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I am /G. I tend to use Fltplan.com recent cleared routes and will sometimes mix up airway and direct.

In those recent routes, for the first trip up there a couple weeks ago, I filed CCV V139 HTO MHT ENE. I was given that as the Expected Route, but the SCHOL DUNFE V139 HTO MHT ENE is what I was actually given by CD (I was also rerouted at least twice by NY and BOS while enroute, but that is pretty common when flying through that area.

Out of curiosity, why would't you have accepted those routes?
 
midlifeflyer said:
...and where are you heading?

@Fearless Tower, just saw your post. Given that Norfolk to Maine is to the north, including both the DC and NY areas, I would not be surprised to see a discrepancy between expected and cleared.

But I have another possibility to look at. Are you using the "Routes" function in ForeFlight to choose what you file? If so, I think that has been a FF weakness when compared with sites like FltPlan.com when it comes to reality. I've seen a number of situations in which FF defaults to a pure airway routing, which will be fine with the computers that "approve" expected "Center" routes, but have no relation to the real "TRACON" routes ATC assigns through areas like that.
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Where I was heading is how far is FF going with just giving what's filed as the "expected." He had said that about a month ago it started doing that, always giving the filed as the expected. I was wondering if it was literally just doing that for some reason. A test would be to file a ridiculous route and see if it did that, give the filed as the expected.

I was putting in some departure/destination pairs out east there in FF and seeing what routes it offered up. It didn't have a TEC category like in the Los Angeles area. Plug in KSAN KSBA to see what I'm talking about. I looked in the Northeast A/FD and found there is a TEC system there. It goes from Norfolk all the way up to Bangor. It starts on page 515. They don't "code" the routes like the do out west. Maybe something there put some light on the subject.
 
FF does not makeup the expected route, the FAA ERAM computer does. FlightAware and FF are the messenger. In Southern California the TEC routes are named and can be assigned by name or a full route clearance. A good deal of the SC TEC routes would not be accepted if entered in detail, and can only be described by name. With new technologies where a datalink is used to download the route directly to the FMS, these routes can't be used. The FAA is slowly overhauling its preferred routes to make them loadable. Some of the issues making them not loadable into the FMS are radial routes, radials to intercept an airway, named fixes that are not in the NAS database.
 
John Collins said:
FF does not makeup the expected route, the FAA ERAM computer does. FlightAware and FF are the messenger. In Southern California the TEC routes are named and can be assigned by name or a full route clearance. A good deal of the SC TEC routes would not be accepted if entered in detail, and can only be described by name. With new technologies where a datalink is used to download the route directly to the FMS, these routes can't be used. The FAA is slowly overhauling its preferred routes to make them loadable. Some of the issues making them not loadable into the FMS are radial routes, radials to intercept an airway, named fixes that are not in the NAS database.
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Any explanation for why the OP noticed a month or so ago that the "expected" he got for FF started being whatever he filed?
 
V139 - the "MANTA" route is common clearance from DC -> New England. SIE, V139, HTO, thence onward. The over-land route at any reasonable altitude is up over IGN or PWL. I've accepted the MANTA (I call it the "shark" route) clearance at 17,000 in a turbocharged single without too much concern - at that altitude the glide distance was sufficient that I'd not be able to glide to shore for a period of 10-15 minutes, which was a risk I was willing to accept given that the route crosses over the major shipping lanes into NYC, meaning there is a higher probability of rescue should one ditch. 15-17,000 is high enough to weave into JFK arrivals on V139, assuming it's not a push time.

Out of DC, I used to get clearances that were in line with what showed in FF when westbound, to the north, however, I generally got a different route. TEC was common unless at reasonable altitude.
 
luvflyin said:
Any explanation for why the OP noticed a month or so ago that the "expected" he got for FF started being whatever he filed?
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Sure, that is what ATC ERAM is going to give you if it can. The vast majority of routes ERAM spits out are the ones that are filed by the pilot. FF monitors for an expected route and passes the first one along. Sometimes the route is subsequently changed by the local ATC or flow control or weather.
 
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