APPR Mode Problem

Hi IFC,

a couple of days ago, I made a similar topic on how APPR mode is not functioning right for me. Whenever I activate it, the aircraft violently swerves left and right and can never seem to align properly. Here is a sample video of what happens upon activation:

Upon review of the video, it was determined that the problem was that I was activating too early and at very slow speeds (160 knots)

I tried to resolve this issue by activating APPR at 180-200 knots and between a 30 degree angle of approach for the ILS. However, this also seems to not work. I have tried activating APPR with both the B772 and B77W and it did the same thing: aircrafts swerved left and right violently trying to get aligned with the ILS and ended up almost crashing. I was forced to convert to a visual approach on both occasions.

Just some notes before we see a lot of the same comments below:

  • I HAVE already watched the APPR video made by Tyler and I have been over my methods by comparing them with this

  • The aircraft was configured properly and was not overweight

This is very weird and I have never experienced this up til the last two weeks. Can someone please help with this. I would love to get back to those smooth ILS landings. All help is appreciated and thanks in advance! 😄

EDIT:

I took some time recently to make another video detailing a similar approach with a few modifications from the above video. Here it is:

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In order for APPR to work you have to activate it while your established well on the glideslope (the green diamond next to your alt. indicator) in the video you were not established on the glideslope yet.

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I understand this and have reviewed it with Chris_S. However, i don’t understand how the altitude indicator has anything do with with malalignment. The aircraft still should not swerve violently left and right even if the green diamond is not next to the altitude indicator

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APPR will not work properly if it is activated without you already being on the glideslope.

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But I was perfectly aligned. If you see, I was head-on directly aligned with the runway and with the GS. Still the aircraft swerved left and right, which should not happen. If the altitude was off because the green diamond wasn’t next to the altimeter, then I would expect the aircraft to fluctuate violently between the vertical speeds going up and down, not left and right

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At 5:30 you activated APPR, when you did that you were not yet aligned or established on the glideslope, the APPR will take care of your heading for the localize, but unless you activate APPR while you are aligned on the glideslope, the APPR will not work.

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I understand this, and that is why I went over it with Chris_S. However with the situations from today, I was perfectly aligned with the ILS from RJTT and LFPG. However, the aircrafts both swerved left and right.

I will try to upload both these landings (I’m not sure if it’ll work as those both were 13 hour flights)

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Well I dont know of any reason why your plane is doing that if you activate while aligned on the glideslope, every time i’ve used APPR it works fine even with my heading, last time I told someone to uninstall to try and fix something I got yelled at so I wont tell you to do anything like that (lol). Hopefully you find your solution soon!

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Although you were slightly aligned did you ever switch the nav to nav1 before turning on appr? After skimming through seems like you just did it too early.

I did not. However, I have never needed to set to NAV1. It used to work just fine without turning to NAV1. Besides, doesn’t NAV1 simply change the compasses source to show the ILS alignment? It doesn’t actually change the aircrafts NAV system from the waypoints entered in the FPL. I have found that it does very minimal and whenever I used APPR in the past, it has worked just fine without turning to NAV1

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But he isn’t talking about the glide slope he is talking about the localizer. I have the same problem. It turns very violently when I activate APPR.

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Yea it used to be that way but switching to NAV1 before turning on the appr the aircraft will align with the ils first. That should fix the swaying issue. But if you are comfortable with manually controlling the descent you don’t need appr.

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That is false. You can be a little off glide slope. You don’t have to be perfectly on it. The localizer is the problem.

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I have never seen this occur. I have had a handful of experiences where I have tuned to NAV1 and assumed the aircraft would automatically line up, however, what happened was the aircrafts always overshot and never changed course at all. I just need help with the described violent swerving. It ruins all my approaches

What I do is I add wave points to line up on the runway so when I activate APPR the swerving isn’t as bad but it still happens especially when there are some bad winds.

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I didnt say you had to be perfect on the glideslope for APPR to work, I said it works better if you are at least established :)

I understand this. I do this exact thing with all my flights. I try to align perfectly with the runway. Again, this has never happened to me until very recently (past two week)

I stopped using appr a long time ago for it being inconsistent and totally ruin a long haul flight. I just use nav1 for the guide but I still fly the approach myself so I know it will go perfect.

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Same. I don’t know what do do to fix it either.

Nav1 doesn’t work for me it doesn’t line up with the runway.