I've just started using the simulated ATC in FS9, and have no experience with real world ATC. On a recent flight from KRDU (Raleigh/Durham, NC) to KILM (Wilmington, NC), I encountered something that would surprise me if it's typical of real-world ATC, and I wonder if someone could comment on whether it might really happen this way.The wind was 9 knots from 233 degrees, so it's natural they initially routed me in on runway 24. But I wanted to try an ILS approach, and requested runway 35 (the only one at KILM with ILS). My request was accepted, and each controller from 71 miles out routed me toward the ILS approach. Even KILM approach gave me the final command to turn left, heading 080, maintain altitude until intercepting the ILS and land on rwy 35. Then they handed me off to KILM tower, who promptly cancelled the ILS landing and directed me to a visual landing on rwy 24.Okay, fine, I'll land where they tell me.But in the real world, wouldn't KILM approach know if KILM tower is not using rwy 35, and tell me to land at rwy 24 instead? For that matter, would the controllers between KRDU and KILM know enough about KILM's active runways to deny my request for the alternate runway? In the real world, I'd have been disappointed to spend the extra time and fuel lining up for rwy 35 (KRDU is north of KILM) if it could have been predicted in advance that I would not have been allowed to land there.Or is it possible that FS9 is simulating a situation in which ATC tries to give me the approach I want but at the moment I arrive other traffic needs overrule my preference?

Good questions. I've never had an ILS cancellation. Hope someone can shed some light.Alex M.

It looks like you requested the ILS approach to RW35, but NOT the runway (they are two separate requests), so FS ATC will honour your request, and give you the approach to RW35. But once you're inbound on the ILS, they will still require you to land on the original runway. You'll need to request a different approach AND landing runway.Cheers,Gosta.http://www.hifisim.com/images/as2betateam.jpg

In real world, you can ask for and possibly get an ILS for guidance subject to traffic flow restrictions. Then, you may get a circle to land or side step to the final runway in use although I think the the final runway is always up to the pilot in command. I always get side steps in FS9 when I pick another approach.I remember shooting a real world Worscestor MA, ILS 29 going the wrong way (Heading 110) in LIFR - read pounding rain and bad visability and then executing a full pattern entry right below the cloud deck at 1100 feet once we broke out! Very thrilling to say the least.

"Gosta" below has the correct answer for this.However, it's not that unusual to have ATC assign you an ILS approach and then have to land on a different runway for wind, or any other reason. However, ATC will always tell you that it's a "circling approach to runway xy", as they do indeed know about which runways are in use at controlled airports. They may not know which runways are in use at uncontrolled airports, so in that case you would just be given the clearance to the ILS, and you would need to determine the need for the cicling to land yourself based on the traffic advisories that you picked up from the FBO.It's important to know that the approach is indeed a "circling approach" early on in the procedure, as they usually have greater minimums. They also require you to have the airport in sight at all times while circling, otherwise a missed approach is required.Bruce.

Thanks for the answers. Gosta is correct that I only requested a changed approach, and did not request the new runway separately. And Bruce is also correct about the circling approach. I remember when I first got approval for the approach to rwy 35 that the ATC instruction included a reference to "circling." I didn't know what that meant at the time, but thought if it applied to a contingency that might arise if my requested approach were not available when I arrived.So what specifically does the "circling" refer to?

Hi,A "cicling" approach is defined as an approach that is not aligned with the runway that you are to use. There is actually a defined angle of mis-alignment that meets the "circling" definition, which is 30 degrees. So if the runway alignment with the approach is off by more than 30 degrees, it's a circling approach.ILS's are not circling approaches as long as the ILS is for the runway you are landing on. The same would apply to a Localiser (LOC) approach. However, if the wind favors runway 18 (wind is from 180 and is strong enough to need you to land on 18), but 18 does not have an ILS- but runway 27 does have an ILS, then you could use the ILS or LOC approach to 27, then at a pre-defined altitude (which is the "minimums" shown on the approach chart) you would then commnce a "circle to land" on 18. If at that "minimums" altitude, or at any time during the circling manouver, you lose sight of the airport (eg. cloud), then you MUST execute a missed approach.Another type of approach is a "VOR" approach. VOR's are not usually based alongside the runway as are ILS's and LOC's, but are sometimes elsewhere on the airport site, or maybe even off the airport site totally. In either case, it is possible to be more than 30 degrees mis-aligned and so a circling approach would be applicable. These are shown on the approach charts as "VOR-A" (where "A" is the first approach, then if there's more than one they will use "B", "C", etc.). NDB approaches may also fall into this category.This is probably more than you wanted to know. :) And even here we're just scratching the surface :) .Bruce.

Thanks, Bruce.No, not more than I wanted to know at all. Your answer describes quite succinctly why the routing I experienced happened the way it did. If I'd had the information in your response at the time, I would've anticipated exactly what happened.Now I want to go try some more flights and scratch that surface a bit deeper.

You're welcome.Instrument approaches and instrument flying in general are complex subjects (I should know, I'm doing mine right now :) ). I'm glad that this summerized version answered your question.Bruce.

There's a second situation where only circling approaches are published, in addition to the situation Bruce decribed where the final approach course is more than 30 degrees from the runway direction. That is, if the missed approach point is too close and/or too high in relation to the runway threshold to allow a "normal descent and landing."A good example of this is the famous VOR/DME-C approach into Aspen (KASE). Even though the final approach course is within 20 degrees of runway 15, the missed approach point is 1.4 miles from the runway threshold, and the MDA is about 2400 feet AGL. Unless you're flying a bowling ball, it will be almost impossible to descend and land from the MAP. Therefore, this is a circling-only approach (alpha character instead of runway number appended to the approach title).Of course, if you can see the runway environment before reaching the MAP, you're free to start descending visually. Just be sure there's no clouds between you and the runway!Dan