Hello forum, Today i did a flight from EHAM to EDDF. On my final approach, about 10-15 DME from the runway, i turned on the nav/loc mode. The button didnt lit up, which as far as i am aware of it is supposed to? I tried clicking it a couple of more times, but same result. When i tried to turn on the "App" mode the light of this button didnt lit up either, but VNAV and LNAV turned of a few seconds later and the plane did follow the localizer and the glideslope. Then after that i tried to turn on "CMDB"(to try and engage autoland, rollout and flare), this button did lit up but almost right after that CMDA goes off. Since this happend i assumed i couldn't enable an autoland mode on this approach(for whatever reason), so i just did a manual approach. When i flew the PMDG turtorial flight the autopilot would behave differently, if compared to what i wrote in the above paragraph. When i turned on nav/loc mode, the button lit up and LNAV dissengaged. After i was establshied on the localizer i would turn on "APP" mode and button would lit up for a bit, and then go off again together with VNAV and the other MCP modes. And finally when i turned on "CMDB", both the CMDA and CMDB buttons would stay on and i would eventually make an autoland. So my question is basically, is there an explanation for why the autopilot behaved differently on my approach to EDDF? Or is this a bug? Thanks in advance! :) - Arthur

TBH I feel there are conditions where the AFDS would exhibit quite odd behavior. I've seen similar things to what you describe, although in my case the G/S part of the APP mode wouldn't arm, for whatever reason. Other than that, once fully established it's perfectly normal for the APP light to go out, indicating it cannot be deselected by pressing the button again. The LOC knob however doesn't have this. Not being able to arm the second AP might also be due to not being fully established on the ILS, or being too late at altitude. Next time, make sure your FMA reads something like FMC SPEED | LOC | G/S and make sure you're well above 800' RA. Then hit second CMD.

Other than that, once fully established it's perfectly normal for the APP light to go out, indicating it cannot be deselected by pressing the button again. The LOC knob however doesn't have this.

Yep im aware APP should turn off once im established on the localizer and the G/S, which is also what i wrote in the second paragraph. But when doing the EDDF approach the APP button didnt lit up at all when i hit it, though the plane still followed the G/S and the loc all the way to the runway just like it should be doing. So obviously the mode was on. I've done about 7 landings with the ngx since i got it, and i only remember two landings where the autopilot would behave the same way as in the turtorial flight from EGKK to EHAM. So its not only in todays flight that i expirienced the loc/nav mode and the autoland mode not working. Is there anyone else who could shed some light on this? Thanks - Arthur

To get that question back to the top. I have the same problems while approaching EDDF Rwy 25L (ELEV at about 364 ft) My final DECEL point is about 5 miles before the turn in onto final approach. The turn in point has (for my current configuration) the constraint 176/4000. At this point I'm mostly about in 4500 Barometric Altitude.At the DECEL point (and before and behind) I tried on many landings to activate the VOR/LOC button to arm the localizer, but the button won't lit up and the FMA remains at FAC for Roll Mode. If I hit then the APP button the plane captures the glideslope and FMA announces FAC for Roll and G/S for Pitch Mode.No chance to arm CMD "B" for Autoland. But both NAV Radios are set to ILS frequenzy (111.15MHz) and both courses are set to 248°. Don't know how to set up VOR/LOC to make an autoland when on G/S. I flew the NGX only in Germany yet, but most the times the plane turns onto the final approach, with the current AIRAC cycle as database, I am about the G/S and have to chase it, when I do not modify the flightplan. This happened on different Airports, such as EDRZ, EDDF, EDDB. Is that the same in real flying? I'm more that learning by doing person, but I red through the manuals a bit and watched adn red some tuts, so maybe theres something I'd overseen, that solves those problems. Thank, Eric

But both NAV Radios are set to ILS frequenzy (111.15MHz) and both courses are set to 248°.

25L is 110.70/249, not 111.15, as per FSX stock AFCAD. It's in no way sufficient to just set any frequency - if you aint positively and correctly identifying the navaid and are in fact getting no indication, hence could not even fly it manually, how should VOR/LOC be able to do anything either. Luckily it's technically not possible to arm APP or even just VOR/LOC in that case, as you'd be illegal without positive identification. EDDF freqs have mostly changed, but I'm sure you're aware of that. Maybe there's an AFCAD update though, I haven't checked specifically. BTW To make autoland work, technically you need to engage both APs before descending below 800R, have a positive self-test and appropriate FMA indications. Actually check this out. Apparently just came up yesterday, what a happy coincidence. Not only are the frequencies updated, also the new runway is there, plus the taxiway designators as of the change last June (IIRC).

Edited October 16, 201114 yr by badderjet

But when doing the EDDF approach the APP button didn't lit up at all when i hit it, though the plane still followed the G/S and the loc all the way to the runway just like it should be doing. So obviously the mode was on.

Probably still descended on the glide path and followed the correct heading, because you had glide slope on in the FMC. Hence, the aircraft followed an IAN approach, not an ILS approach. Or, you did a VNAV approach.

I allready tried it with the frequencies and courses FSX offers and there did nothing worked. Even no G/S capture.The frequency I work with is the one I got from FMC displayed on the CDU's Approach page. Could it be a incompatibility between the frequencies and courses FSX exspect and the ones the current AIRAC cycles provide?

Does the ILS work with a stock a/c, say the B738? Oh, and by saying 'no G/S capture', do you mean the AP doesn't arm G/S (but arms VOR/LOC), but you do get an indication? Because it does that all the time, when you go around and come back for the approach without reselecting it on the DEP/ARR page...

I was finally able to capture the LOC and G/S many times now. Usually I was used to always miss the both. The reason or difference ? Nothing in particular, I just now activate the LOC as soon as I can ( just when I hear the morse more or less ) and I always pay 125% of attention because I am sure sometimes it will miss them again due to no reason. The autoland appears once every 6-7 landings to me, like the Halley comet, but I have no problem because I always prefer landing manually when I am quite close to runway down the G/S