ILS Back course approach

[Robi77 0]

I know what a back course approach is and how to use it.However I am not sure if is safe to say that all ILS systems have back course capabilities.And what about the glide slopes on a back course approach ?And is there a difference between the real world and the flight sim ?Hubert Werni

[fwerff 70]

As far as I know, backcourse ILS approaches only use the localizer signal and not the glideslope, since that last one would bring you down at the end of the runway, when flying opposite.

[SWA737 0]

What is a ILS Backcource?

[ZachLW 37]

What is a ILS Backcource?

I'll Google it for ya'. :( http://www.google.com/search?q=ILS+back+course&ie=utf-8&oe=utf-8&aq=t&rls=org.mozilla:en-US:official&client=firefox-aIt'd be a "Localizer Back Course" instead of an "ILS Back Course". When a back course has glide slope capability, it is a separate glide slope antenna from the one used on the ILS ("front course") approach. In this case it would be called a "Localizer Back Course with Glide Slope"Taken from the FAA's Instrument Flying Handbook: LOCALIZER BACK COURSEIn cases where an ILS is installed, a back course maybe available in conjunction with the localizer. Likethe localizer, the back course does not offer a glideslope, but remember that the back course can projecta false glide slope signal and the glide slope shouldbe ignored. Reverse sensing will occur on the backcourse using standard VOR equipment. With anHSI (horizontal situation indicator) system,reverse sensing is eliminated if it is set appropriatelyto the front course.

[SWA737 0]

http://www.google.co...lient=firefox-aIt'd be a "Localizer Back Course ".When a back course has glide slope capability, it is a separate glide slope antenna from the one used on the ILS ("front course") approach.

Thanks

[503(V) Driver 0]

All ILS Localizers DO NOT have a back course capability. Here in Canada, both Nav Canada and the Canadian Forces are in the process of changing out old ILS systems with the new ones not having the back course capability. A big part of this is that the back course is not as accurate as the front course localizer due to the lack of equipment monitoring. I know one airline that flies into our airport that won't do the LOC BC approach, but instead does an LNAV overlay.As for glide path, you may get random readouts, but they are to be ignored. I know on the CAP and GPH200 approach plates there is a big warning stating as such.Hope this helps.

[Flamin_Squirrel 71]

There is an easy way to tell if it's safe to use the backcourse of an ILS; there will be a published backcourse approach plate :(

[badderjet 181]

As for glide path, you may get random readouts, but they are to be ignored. I know on the CAP and GPH200 approach plates there is a big warning stating as such.

There is an easy way to tell if it's safe to use the backcourse of an ILS; there will be a published backcourse approach plate :(

Yeah, after all a BC app is a non-prec one, so whatever GS indication you have, your descent path still relies on altitudes, that's it.One more thing, Zach mentioned a BC w/ GS app. TBH I've never ever come across one. Plus I wonder if that would make sense. That would mean one LOC antenna but two GS antennae for one runway, plus that app would be a precision one since it's got GS avail, but a sub-par lateral indication on the back course end. Not saying you're wrong, but yet I seriously doubt its existance. :( The only BCs I've seen so far (on plates, correct), were true non-prec approaches with LOC only, and just the usual altitude game as for your slope.

[michal 44]

There is an easy way to tell if it's safe to use the backcourse of an ILS; there will be a published backcourse approach plate :(

Yes, another important point to remember - not all autopilots have backcourse capability - if they don't you would have to fly it manually.

[ronzie 21]

FS default airports have their LOC back courses enabled.This a not a safe default assumption. In addition, if the same LOC frequency is shared at both ends of the runway in FS you will receive the incorrect one until about within two degrees of center-line. This also results in a false GS if present. To check this know and pay attention to the LOC ID on the PFD before engaging VOR/LOC and APP.Unless a coupled A/P has a REVerse button of BC button or similar, you have to fly the heading manually keeping in mind the LOC display has reverse sensing and you need to turn the aircraft in the opposite direction for those approaches where a BC must be used.Unlike a VOR in working with a LOC the Course selection control has no bearing on the LOC deviation displayed so you can't just reverse the course setting to correct the deflection.

[brucek 38]

Just to add, at least here in the us, while many loc's may have a back course ( function of the loc antenna) , only those with published approaches are legal. This may be obvious since if it's not published then there are no minimums shown either. However, I think that all loc antennae would exhibit a " back course" transmission.As said before, the autopilot may not be able to handle the reverse sensing needed, and many airports now have gps / waas overlays or substitutes , so why would you want to fly the bc approach if you can fly the gps one.Bruce

[ronzie 21]

http://en.wikipedia.org/wiki/Instrument_approachhas a good explanation of all approach types.

[ronmarks 13]

Is it even possible to do a BC simulation with MSFS? Since, in my experience, MSFS always "flips" the simulated LOC course depending on aircraft position to accomodate an inbound course, I don't see how it can be simmed as a reversed indication. Maybe I've missed something. Another result of the "flip" is that the localizer DOES reverse when flying outbound, say on a missed approach, and that bugs me. In the real world that doesn't happen, which gives you a nice, dependable directional ref when you need it most - on the climb out after going missed.Another anomaly with the MSFS localizer is that it shows up on the RMI as though it was a VOR or TACAN signal. Without magic, there is nothing in the LOC signal that can make that birddog function work on an RMI .Maybe this stuff has already been discuss to death somewhere, but I haven't seen these sim/real world differences mentioned.r

[Houghton11 12]

Ronmarks,What aircraft are you flying? If flying with one equipped with an HSI, you just flip it 180 degrees from the normal localiser course and it will show 'correct' course deviation indications when flying the back course. This is how it would operate in the real world as well.When using the ol' OBS circle gauges in the default 172, I get correct reverse indications when flying a BC in FSX.

[ronmarks 13]

Ronmarks,What aircraft are you flying? If flying with one equipped with an HSI, you just flip it 180 degrees from the normal localiser course and it will show 'correct' course deviation indications when flying the back course. This is how it would operate in the real world as well.When using the ol' OBS circle gauges in the default 172, I get correct reverse indications when flying a BC in FSX.