Intercepting Approach

[Guest prdant]

Ok, looks like I have lost what little mind I may have had. When flying on autopilot and having the ILS approach freq entered I click the APPR button on the autopilot but it never goes active. I recall in FS9 that it should lock on and make the turn and alt reductions until I turn off the AP. Having said that does the the freq go into NAV1 or NAV2, can't recall and in fsx I seemed to have had no luck with either. Ideas??

[Guest azflyboy]

Make sure that you are tracking inbound on the localizer (the CDI needle should be moving towards the center of the gauge), and that you don't have a massive intercept angle when approaching the localizer. You should always intercept the glideslope from below, and once it goes active (the glideslope needle should un-peg itself and start centering up), then engage approach mode and shut off the altitude hold. Also, be sure sure you have the ILS frequency set into the right nav radio (it should be nav 1 for most aircraft), and that you're not trying to track the localizer or glideslope from too far away.

[Guest prdant]

Thanks, I will try NAV 1 this time, I was flying a heading of 225 as assigned by Radar Contact and had the rwy heading of 194 set in the course window. The ILS just never came alive.

[Guest NeXTer]

Also make sure you have the NAV/GPS switch in the former position. Been there, done that, had to go around. :(

[Guest prdant]

Thanks, thought I did but will verify and try again.

[RFields5421 1]

What airport, what runway, what ILS frequency?There are many localizers which do not have glide paths in FS.There have also been issues where the default "Back course Enabled" in FS has caused people to lock on to the localizer at the opposite end of the runway.I vastly prefer an instrument set which shows the ident of the localizer.

[Guest azflyboy]

>There have also been issues where the default "Back course>Enabled" in FS has caused people to lock on to the localizer>at the opposite end of the runway.>>The Back Course button shouldn't track a different localizer, since a back-course approach in the real world uses the exact same navaid as an ILS approach, but from the opposite direction and without a glideslope. If FSX is anywhere near realistic, all the back course button should do is cause the autopilot to reverse it's steering commands, since flying a back course would otherwise cause it to correct the opposite direction that it needs to for proper tracking. Something else that might help with flying ILS approaches is to learn to read and follow real-world approach plates in FSX, since most approaches in FSX are actually surprisingly close to their real-world counterparts, and the ATC is pretty terrible for approaches much of the time. The FAA actually has every approach plate for the US available for free online at http://naco.faa.gov/digital_tpp.asp?ver=07...&end=12-20-2007Most of these approaches can be flown correctly in FSX, but be aware that FSX seems to use a database that is somewhat outdated and is missing quite a few GPS approaches.

[scott967 62]

I think the problem that is being referenced, is the possibility of ILS localizers with the same frequency on both ends of the runway (common in the US). Since the default localizers have backcourse available, you have the situation that two localizers (one near - backcourse and one far) are both received. Never happened to me that I know of, but I guess it could. That's why IRL there is a transfer switch that prevents both systems from radiating at the same time.scott s..

[Guest prdant]

It is rwy 19R at KSNA 111.75. I was able to make it work. I must have had the ILS freq on the wrong NAV radio.Thanks to all

[RFields5421 1]

The FSX database is Apr 2005, the FS2004 database is Oct 2002. Jeppsen approach charts of those dates match FS exactly. Those dates have been widely reported on these forums for a very long time.Flight Simulator has several things which make expected real world ILS behaviors not occur when procedures are followed perfectly in the sim.1. EVERY localizer in the world has backcourse enabled and 'transmits' a back course signal 100% of the time.2. FS does not transmit any signals and radio signals are not subject to real world rules - but operates in an artifical perfect world. Also all transmitters are on and transmitting a full power all the time.3. As Scott noted above - at a large number of airports the two localizers on opposite ends of a single runway transmit on the same frequency - and both also transmit a back course signal at the same time on the same frequency.The result is the unless the inbound aircraft is on a heading within two degrees of the localizer heading - the aircraft will NOT capture the localizer for the inbound runway - but will capture the backcourse of the outbound runway if the inbound runway is the secondary end of the runway. It will also occur when inbound to the primary end on many occasions. (The UK is where I get this happen alot Scott - EGSS is a pain).This occurs because the localizer 'transmitting' the back course is usually two to three miles closer to the user aircraft than the localiser 'trasmitting' the problem ILS w/ Glide Path information.This is with the APPR button selected on the autopilot. The aircraft will not capture a glide path signal.So it is possible to follow this approach plate perfectly - http://204.108.4.16/d-tpp/0712/00166IL28.PDFbut what you get is a backcourse signal for this approach - http://204.108.4.16/d-tpp/0712/00166IL10.PDFThe only clue will be that the Glide Path does not appear and the aircraft does not descend as you overfly the airport.That is why knowing the IDENT of the localizer you are trying to capture, and having a way to identify the localizer being received on NAV1 is so important.In the real world, neither of these localizers has a backcourse signal. Also KORD is not going to be transmitting two localizers for one runway for approaches in opposite directions at the same time.Real world procedures are extremely useful - because that is how FS is setup to work.Understanding the places where FS deviates from the real world and how it impacts the sim pilot is also very important. Especially when we are trying to diagnose problems.

[RFields5421 1]

KSNA is a unique airport in the FS world.It has two localizers on Rwy 19R.IOJW is on 108.3 and is for an LDA approach on an inbound course of 181 degrees. It has no glide path. In the real world the localizer has no backcourse - but does have one in the FS world.http://204.108.4.16/d-tpp/0712/00377LDA19R.PDFISNA is on 111.75 and is an ILS with Glide Path and a Back Course. The inbound course is 194 degrees for the Rwy19R ILS.http://204.108.4.16/d-tpp/0712/00377I19R.PDFQuite a few people see the localizer arrow in FSNav for FS2004 and set their NAV1 radio for 108.30. It is a very easy mistake to make.This is the only known airport with two localizers on the same runway in the FS world.There is an addon which adds the second localizer to KASE Rwy 15 for FSX.http://library.avsim.net/esearch.php?DLID=...vile&CatID=root