Ever since I learnt how to do ADF approaches I realised they solve my biggest problem with approaches, when to turn out of base to final, without doglegging to a mile out, or overshooting the LOC.I would watch the ADF needle as it points to the ILS signal until its 5 or 10 degrees or so closing in on the ILS course, then I would turn in. If I was too soon I could just do a standard "push the head", "pull the tail" on the ADF needle to find the LOC. Doubling the offset.However, as the PMDG 737NG draws distinction between ILS's and VORs it refuses to show the ADF needle for the ILS. This leaves me with either having to use NAV2 tuned to an on field VOR or find an on field NDB for the same purposes. I don't like using NAV2, for a number of reasons. Primarily it is usually being used for a reference for the approach, transition or for a MA. Or it might be required in low vis for a CATII dual channel, although I can swap the turnning once im established. The 2 ADFs are usually free, but there isn't always an straight in NDB approach course for the field and runway combination. "Any" on field ADF will usually do if the FAF is a good 10 miles out or more, but a non-lined up NDB isn't very good when you get closer.Is this "feature" with the AFCS distinguishing between LOC and VOR accurately modeled? Is there something wrong with my technique, or is something else going on here? Is there any way to get the ADF needle to point to the ILS signal?Thanks.

I'll try to take a first stab at this one for you Paul...I am not really sure why you would need an ADF or on field VOR to assist you on an ILS approach. The ILS is designed to be a "Precision Approach". I believe your issues have something to do with the procedure you are using to fly the ILS. There really isn't a turn from base to final in an ILS approach. You either fly the full approach procedure (from IAF to FAF ->intercepting the GS), or you receive vectors from ATC to intercept the LOC and then fly the remainder of the approach.If you fly the approach as published, you should not be having the problems you are describing. So I think the first place to start may be to take a good look at an ILS approach plate. Do you have one in particular we could use to discuss? Otherwise I can suggest one.

I am fairly clued up with approach charts and I know what you are saying to me. However... even on approach charts an ADF to the ILS signal can be advantagous, and is even suggested on charts.Firstly my problem is that the ILS beam is very narrow and even with a 30 degree intercept angle you can shoot straight through it, even with APP primed. I find it's helpful to know where the beam is relative to my position.For example take EGAC ILS/DME for runway 22. Starting with the direct in approach for SE arrivals. We have a QDM arc, from the ILS beam. On the 737NG you can't fly the ILS QDM as you have no needle for it. OK, so you can use the NDB for the QDM and the ILS for the DME to maintain the arc (although it isn't exactly specified on the chart, it says I-BH DME 9 arc). There are also cues as to when to trun in off the arc to incercept the ILS (or you hit with a 90 degree intercept).Then looking at the full transition from overhead the NDB, you fly the HB QDM 042 then carry out a proceedural turn. A 46 degree deviation, followed by a 180 to incercept the ILS with a 46 incercept angle. Now, it depends on your profile and how long you stayed on the out leg, as to whether you will capture, come up parallel, or over shoot the ILS beam. If you remain in the 46 degree intercept course you will over shoot the LOC beam.The ADF needle provides much more information than the LOC CDI bars as it tells you your position relative to the navaid, not just wether you are in the beam (and left or right) or out of it.See my point now?

Hi Paul,Don't have easy access to this plate, where can I download it?Thx

www.ais.org.ukSign up is free, contains all UK charts and ERDs etc.Very useful, unless you dont fly to/from the UK ever.

Ok Paul got the chart. I see what you are trying to do now. I have to do some research, but you can use the FMC to program the ARC and then have the LNAV fly it (or hand fly it). It has been a while since I have programmed the FMC for a DME arc. I will try a few things and get back to you.Concerning turning into final, if you use the QDM 259 at 180 knots this should give you plenty of time to turn in for final. Again if programmed properly into the FMC, the map display should give you a good picture for situational awareness what is happening (without the needles.)

Its ok, i already programmed the FMC for the arc although I believe I had an issue with the LOC intercept but thats another story.I find I like to use the radios to navigate in the terminal area for a number of reasons. Some being the freeware STARS/SIDs database being slightly off at times, some being that it adds something manual to the flight and adds challenge. Especially in bad weather. Another reason is that if you go missed, the FMC very quickly deletes the rest of the route and you have to argue with it to even get the proceedure to the hold point back. I think this only happens if your wheels touch tarmac though. I try to practice chart flying using arrival -> touch down -> take off -> missed approach -> MA transition to final and so on. Then flying out one SID and in the next STAR. The FMC doesn't like this at all.On-the-fly (bad pun sorry) programming of the FMC lacks the ability to add Intercepts and things like that, which means you have to program the transition in FMC code. As per the tutorial, I have no problems with doing this, but I can't do it while im in the air.

In the real world it is very rare to turn onto the ILS from a base leg. Normal interception angle from a procedure or radar vector is rarely at a greater angle than 30 to 40 degrees. Increasingly you will not find either any NDB or VOR at an airfield that is usable for the guidance you require. Are you using your flight director in heading mode with the localiser armed. This will give you the turn command to intercept the localiser without any problem providing you are not trying to intercept at large angles. Remember your turn radius at 180 Kt is quite large.Having flown 737s for over 20 years I commend PMDG on the modelling of the AFCS.RegardsChrisY

Thanks Chris,In some ways I have been using the ADF needle to "simulate" vectors I suppose, when I have no ATC and haven't looked up, or couldn't find the charts for the field I was landing at. My charts research is thin outside of the US and UK. I would use the ADF needle (and DME) to know where I am in realition to the field and know when to turn.When I said, "turn from base" I didn't actually mean literally a base leg. I just meant turning in onto the ILS. The 737NG does have a very nice capture from angles from 30 to 60 or so, but not all planes put so much effort into it. A lot wait until the needle unpins and then attempt to turn, when it's already too late.I'm still a little concerned that without the ADF needle pointing to the source of some navaid I feel lost. VORs and ILSs courses are all very well, but unless it's a VOR and you spin the course dial around to find out your QDM from the device you don't actually have a clue where you are in relation to it.Arcs on procedural plates are difficult to fly without a direction needle are they not? My technique was to use the ADF needle to some on field NDB or VOR and keep the needle 90 degrees on, aka with the field always abeam me, adjusting heading to maintain the DME range. On the chart I drew reference to, how would you suggest I know where to turn in? The chart notes, at QDM 246 you should be not below 2000 feet and should start a turn in to the ILS. Without a direction needle this is impossible is it not? The ILS will not tell me its relative location on the ND on the NG. I "suppose" as it says ILS/DME/NDB on the chart title that I am meant to be using the ADF needle tunned to HB-420 for the QDM references.As an aside, outside the UK, primarily in the US I have seen approach transitions that involve ARCs, that are centered on an Intersection with no navaid at all. How in hell do you know your distance/bearing to an intersection with no navaid without an INS, FMC or GPS? The charts didn't say "RNAV required" either.Thanks again for you comments and any help you can offer.

Hi Paul,I'm afraid that I'm one of the people responsible for your problem, in the sense that I brought it to the attention of the developers that in real life an RMI will not point to an ILS, since the kind of signal is totally different from a VOR or an ADF. So in the ND you now no longer have pointers aimed at the ILS. Sorry for the inconvenience...Having said that I have noticed that in the back-up RMI the needles still do point to the ILS. I think it's wrong, but while it lasts :-) it might be of use to you, perhaps?Leo Bakker

>Firstly my problem is that the ILS beam is very narrow and>even with a 30 degree intercept angle you can shoot straight>through it, even with APP primed. I find it's helpful to know>where the beam is relative to my position.Are you flying in MAP mode?In your post, you keep mentioning the fact that you might "shoot straight through the ILS course".Hey, I know what your trying to achieve, but it sounds like your trying to fly the NG like a "round dial" airplane, a common mistake for new pilots. Are you flying in MAP mode or APP mode when you are trying to fly your ILS approaches? You should be flying the NG in MAP mode all the time unless there is an FMC failure. In MAP mode you can see the ILS course depicted on the MAP and know the airplanes position at all times relative to the ILS course. In CTR MAP mode you can see the head and tail of the ADF needle and still use it for airplane position information if you want to. Floyd

Thanks for that.I am starting to come round to the thinking that I should almost completely ignore the ILS signal until I am near the intercept of the "feather" or "beam". Using other navaids to get into position, be they VORs or NDBs.The point made my ChrisY though:"Increasingly you will not find either any NDB or VOR at an airfield that is usable for the guidance you require."Confuses me. Are you saying that radio nav will be removed completely in the terminal area? I wouldn't have expected that to happen for many years to come. Apart from small aerodromes that are more or less VFR only I think all airports have at least an NDB. More often 2 or more NDBs and often 1 VOR or more.The information I am looking for on approach, is simply, "What is my bearing and distance from the airport."Nothing more. Based on those 2 pieces of information I can pretty much "picture" my location on the map quite easily. In fact, with only the bearing to the airport, a little manouvering and a stop watch I can place myself within a few square miles.I am not looking for a proper aligned NDB approach or a VOR approach, just my relative position to the airport.So to end this, I have my solution. DONT use the ILS for bearing to the airport (unless you happen to be "in the beam"), as this is a sim induced bad habit that won't work in reality. Am I correct?

PaulYou have really answered your own question. The procedure you quote is an ILS/DME/NDB. It means exactly that. You therefore must have the ILS tuned with its correct inbound course and its associated DME AND the NDB mentioned in the procedure so that you have directional guidance.You must have the NDB pointing on a needle and the DME to tell you where you are in relation to the ILS.On the 737 if you have your route displayed on the map you will also have a picture of where you are BUT beware as in the real world map shift can and does occur occasionally so the map could be subject to error. You must always use all available aids to crosscheck and confirm your position. I appreciate in the above case you are probably not using the map.Dont forget VORs also can be displayed on a needle too then it is easy to see where you are in relation to them.The only time when you dont need a needle pointing at an NDB or VOR to help you to find where you are in relation to the ILS is when you are positively identified by radar and you are under their direction but you would be a fool to rely on that in some areas of the world!

>"What is my bearing and distance from the airport."Just one more thought: you could put the airport in the FMC fix page and look at that every now and then for bearing and distance. Or the first waypoint on the ILS.Leo Bakker