Hello Everyone,At many of the airports in the FS9 world, the ILS NAV for both approaches to a physical runway are the same. For example, ILS NAV for rway 12 is 103.50, while the NAV for rway 30 is also 103.50. Obviously, one of the approaches will use backcourse for proper operation. However, I have not been able to determine which is which, and often find myself merely guessing. I have looked at the various charts, and still haven't found the solution.Does anyone know the correct proper way to determine which is which? Is there a notation on the ILS charts that indicate this? If not, how is everyone doing this? I'm hoping there's a better way than the guessing I'm doing right now thx,orbmis

Im just wondering what charts you are looking at exactly. If the chart does not say ILS Backcourse approach then it isnt a backcourse approach

ILS NAV for rway 12 is 103.50, while the NAV for rway 30 is also 103.50. Obviously, one of the approaches will use backcourse for proper operation.No - that is very seldom the case.For a tremendous number of real world airports world-wide, they just turn off the power for the localizer / glidepath for the runway end not in use. This is especially true if both ends of the runway use the same frequency.If Rwy 30 is active - you cannot pick up the signal for the Rwy 12 localizer.Unfortunately in FS2004, the default setting for all localizers world-wide is Enable Back Course=True.Even for offset localizers like LFPB Rwy 25 and PHNL Rwy 26L.Because FS cannot turn off a localizer antenna - this creates a major issue at airports with both ends of the runway on the same frequency.By design if given the choice of two items - FS will choose the lower one.Thus if you fly into EGSS and want to land on Rwy 23 - after tuning your NAV1 to 110.50 - you will see ISED as the ident of the localizer - the one for Rwy 5, not ISX the ident for Rwy 23.You will have no glideslope because FS will "think" you are flying a backcourse on Rwy 5, not an ILS approach to Rwy 23.It's one big screw-up - probably the biggest one in FS2004. Hundreds of airports across the FS world are unusable and unstable.One of the very first things I do when planning a trip to a new airport is to open the AFCAD and make sure that "Enable Back Course" is not selected for any ILS/ Localizer at the airport, unless the approach chart specifically shows a backcourse.If both ends of a runway have the same localizer frequency, I disable the back course....period.... no matter what the approach chart says.

While not disagreeing with Reggie in the fundamentals I must take issue with that statement "Hundreds of airports across the FS world are unusable and unstable"Why? You don't NEED an ILS to land at an airport, and there are still many thousands of international airports with no landing aids.Pilots land airplanes at airports, not instruments! :)But I agree the FS solution is actually creating a problem, not resolving one. :(Allcott

But Reggie has noted a key point, that I had not thought of... That is, the the Ident will indicate which of the rway ends the NAV1 frequency is truly attached to. Would this issue be resolved by checking for the proper ident code? If the NAV1 setting is correct, and it brings up the ident of the 'other end of the runway', wouldn't setting the backcourse 'on' resolve the issue? I would think this would cause the ILS to lock on to the 'other rway' approach. The exact situation I have is at KBOS, where both rway 4R & 22L have the same ILS NAV of 110.30. If I am attempting a ILS approach/landing using rway 22L, and set the NAV, it throws me far off course. I believe that FS is thinking rway 4R, rather than 22L.Or.... are you saying that 22L is --not-- a backcourse approach, and I am not able to do an ILS to that runway at all? (Without modifying the AFCAD)Great discussion!orbmis

When I'm on approach and see that happening - I usually disengage the autopilot and use the backcourse signal for lateral guidance until I can land visually.The current FAA charts for KBOS are:ILS OR LOC RWY 04RILS RWY 15RILS RWY 22LILS RWY 27ILS RWY 33LILS RWY 04R(CAT II)ILS RWY 04R(CAT III)RNAV (GPS)RWY 04RRNAV (GPS)RWY 15RRNAV (GPS)RWY 22LRNAV (GPS)RWY 27RNAV (GPS)RWY 33LVOR/DME OR GPS-AVOR/DME RWY 15RVOR/DME RWY 27VOR/DME RWY 33LNo real world back course approaches currently for KBOS. All five of those localizers have Enable Back Course = True in FS2004 - and not one of the plates shows there is a backcourse on any of the five localizers in the real world.The problem with a backcourse is there is no glide slope, no vertical guidance. There is lateral guidance and people should be able to land without a glide slope.As noted above real pilots flying real jets - B737 size and larger - make landings every day on runways without a ILS.The part about FS which bugs me is as you described above - FS thinks you are tying to land on Rwy 4R not Rwy 22L. The APPR mode programmed into the autopilot implementation system can't handle that.Yes, Microsoft has made an ILS landing on Rwy22L at KBOS impossible in FS2004.It's not your fault - this one rest squarely on their shoulders.You have to fix the issue by changing the localizer properties. AFCAD is the easiest way to do that.

It is definately the case that for addon airports that use the older FS2k2 runway command to specify ILS that it will not work if the same freq is assigned to both runway ends and running in FS9. The ident won't show for it either. I decompile these using BGLAnalyze and strip outthe ILS data, since the FS9 AFCAD will supply this, even when using older scenery. scott s..

The problem may appear only with (old) addon airports like suggested above. I doubt it

Are you using the default AFCAD? With both ILS localizers set to Enable Back Course?

KISP uses the same frequency for ILS 6 and ILS 24. However, both of these approaches are front course approaches. KISP ATC tower personnel manually switch the ILS to match the active runway.Backcourse approaches are specifically identified as such in approach plates. In the header section of the plate a backcourse approach is identified with the words "ILS Backcourse".MS doesn't model this detail. If you tune 108.3, for example, you can fly the ILS 6 and also the ILS 24 and both will function as normal front course approaches.In MS, as in real world, to determine which approach to use, listen to ATIS, or if on an IFR plan the approach controller will tell you which approach to expect well before you get vectored onto the final approach course.

Just hoping for a clarification regarding your post - are you saying that an ils doesn't have a backcourse if it isn't charted, meaning that there is no signal radiating out behind the runway?All localizers have a signal that radiates out in front of the runway (frontcourse) and a signal that radiates behind the runway (the backcourse). If there is no backcourse charted for an ILS equipped runway, it doesn't mean the signal doesn't exist behind the runway, it just means that there is no approach procedure that has been charted for the backcourse. If you want to duplicate this real-world characteristic it makes sense to have enable back course option set to true.You may ask why, if localizers radiate signals in front and behind the runway, there isn't always a backcourse approach charted for every ils equipped runway? I don't know, but it could be related to: 1) back courses approaches don't have vertical guidance, and 2) when flying a back course you have to interpret the CDI indications on the VOR differently than from flying a frontcourse or tracking a VOR radial. This added complexity can make flying a backcourse approach a bit more challenging that a normal frontcourse approach.

Hi,yep, everything default. I didn

>All localizers have a signal that >radiates out in front of the runway >frontcourse and a signal that >radiates behind the runway (the backcourse).>Most Localizer antennas here in the USA DO NOT have backcourse signal capabilities. Modern localizer antennas are highly directional. If a runway uses the older, less directional antenna then a non-precision localizer backcourse may exsist if it is not blocked.Highly directional antennas (Localizer for ILS, LDA, SDF) in service today at most airports DO NOT provide a sufficient signal to support a backcourse. Here in the USA, backcourse approaches are commonly associated with Cat I systems at smaller airports that do not have an ILS on both ends of the runway.There are no transmitters in FS9 and as Reggie said no way to turn off the ILS systems that are in service simultaneously. Real world reciprocal ILS systems are not in service simultaneously. ALL backcourse math calculations in FS9 should = FALSE or untick the box as seen with AFCAD unless there is a published approach plate that says a backcourse approach exsist(example KJAX RWY 31).FS9 in some situations (needle deflection) has a hard time distinguishing between a frontcourse vs a backcourse when approaching the runway outside the FAF on a 30 degree offset heading. This becomes more of a problem when both ends of the same runway use the same ILS freq. and backcourse is enabled.

There does appear to be a very narrow window - probably less than five degrees width on the runway true heading - where FS will read a correct localizer and capture a glide path on a situation with both ends of a runway having back course enabled on the same frequency when landing on the runway with the higher true heading.But a lot testing has shown this to be too unreliable and inconsistent for most people to use.And yes, every single LOCALIZER in FS has the back course enabled as the default setting. Obviously something done by a batch process.

Antennas can be built to reduce rear transmission. Any reception of front course only localizers from opposing approaches are generally "ghost" reflections and are not dependable.You also can get ghosts of GS on a back course and have to know enough not to depend on it.In some cases because of traffic or terrain, back course approaches may not be suitable for every runway having a front course approach.Those generally have unless caused by physical restrictions a circle to land approach visual conditions permitting (keeping runway in sight during pattern).