Reversed ils

[geoffwaldron]

Hello fellow simmers,

I consider myself reasonably knowledgeable and experienced in FS2004, but there is one problem that has bugged me for a number of years and which I have been unable to resolve. At some airports, when I tune in to a particular ILS frequency, I seem to be receiving the 'opposite end' - ie, the localiser needle deflects to the 'wrong' side and there is no glideslope indication. I do have quite a lot of addon sceneries installed but I have not been able to identify any particular pattern as yet, regarding the airports affected.

I seem to recall that previous versions of MS Flight Simulator had a 'switching option' for this problem in the menus, but I have not been able to find it in FS2004. I would be extremely grateful anyone can explain this phenomenen and how I can put it right. Until then, I remain 'in the hold'. Thanks.

[n4gix]

That is a typical "Back Course" signal, which -as you've found already- has no glideslope information available.

Not every airport in the real world with an ILS installed has a BC available, but in the 'FS World' every airport with ILS installed has a BC available, real or not.

Rather than typing out a full narrative here, simply do a Google search for "How do I use a back course" and you'll find tons of info.

[mgh]

I'm under the impression that back course approaches are mainly a US and Canadian(?) phenomenon. They are not permitted in the UK nor, I believe, in the rest of Europe.

In the US the FAA says "do not use back course signals for approach unless a back course approach procedure is published for that particular runway and the approach is authorized by ATC." Are there many published back course approach proceedures?

[n4gix]

Gerry, the reality is that BC approaches are disappearing quite rapidly. I personally know of only six that remain more-or-less in use, although I'm certain there are more still active. The main reason for their disappearance though is that as existing localizer antennas are replaced, they are mainly newer directional antennas that no longer provide enough signal from their backside to be useful. This also allows the power to be lowered a bit, extending the life of the transmitter significantly.

However, the question asked was "how to fly a BC approach" not whether such are still in use or how common they might be. For that reason, I can highly recommend this very interesting and highly readable article by Bill Cox in Plane and Pilot published just over one year ago:

[hide][top]Making Sense Of The Back-Course Approach

http://www.planeandpilotmag.com/prof...-approach.html

[mgh]

I was simply interestd to know how common they are, given there are none in the UK.

[tvieno]

I was simply interestd to know how common they are, given there are none in the UK.

PACD, Cold Bay, Alaska, US has a published back course. http://flightaware.com/resources/air..._DME+BC+RWY+32

edit: for some unknown reason, I thought you wanted to see one published. Well, enjoy the link anyhow.

[mgh]

Thanks, I did want to see one.

The missed approach seems to be determined by localiser limitations - "Localiser unusable inside CBD VORTAC 6.2 DME"

[jvile]

I was simply interestd to know how common they are, given there are none in the UK.

In FS9 there are 184 Localizer BackCourses that can be selected. The default ATC will honor the Pilots request for these type approaches. You can also see them in the GPS.

In FSX there are 167 Localizer BackCourse approaches.

This count comes from Jon (Scruffyduck) at ADE9X by scanning the airport approach data.

As Bill says, many are going away and in some cases being replaced with a ILS. The mimimums for some of the localizer BC's are the same as the front course localizers.

If someone needs to practice this type approach then go to Airnav and open KHUT. Download the Runway 31 pdf approach plate which has a BC with several arc transitions. If the airport is IMC and the winds favor runway 31 then you can decline the GPS approach that ATC will assign and ask for the localizer Backcourse (LBOC) approach.

jim

[jvile]

I'm under the impression that back course approaches are mainly a US and Canadian(?) phenomenon. They are not permitted in the UK nor, I believe, in the rest of Europe.

In the US the FAA says "do not use back course signals for approach unless a back course approach procedure is published for that particular runway and the approach is authorized by ATC." Are there many published back course approach proceedures?

Both FS9 and FSX scanned a BackCourse published chart into the nav approach database for ENLI which is in Norway. However as you pointed out there are none in the UK.

[mgh]

I can't find ENLI in the Norwegian AIP

https://www.ippc.no/norway_aip/current/AD_eng.html

I believe it's now closed.