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Guest Dashik1

757 CAT3 Autoland Problem.

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Guest danielpercy

I have suffered this exact same problem on the 777 with Patch 2 installed - at the end of a KSEA-EGLL sector, carrying out a CatIII Autoland on 09L @ LHR in calm winds, CAVOK. Flaps were set at 25, and I had VRef+5 dialled into the MCP (about 170kts) if memory serves. I had the DH set to 200ft Radio, and the approach was proceding normally (LAND3 was on the PFD). Somewhere between 50 and 30ft, the aircraft rolled sharly left / nose down and struck the ground. I suppose it could be something in the code for both autopilots relating to the AP transition to FLARE (is there some common code between the 757 and 777 in this area).I don't have any other add-ons installed, just a clean copy of FS9 and the PSS 777.Could Norman and the guys at PSS look into this??Daniel Percy

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Guest Phoenix5

Just out of curiousity do these approaches that you are having issues with, do they have a missed approach component? After the threshold does the route end, or does it show a missed approach escape route, that maybe incorporates a steep climb/turn. If it does try removing the missed app part and see if the issue still arises.

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Steven,Look up in the thread for my input on why it happens. I had experienced it numerous times on the mentioned aircraft without ActiveSky, or any weather at all.LHR has no missed approaches programmed AFAIK. Even if it had, the first portion is always a climb on runway heading.>Just out of curiousity do these approaches that you are>having issues with, do they have a missed approach component? >After the threshold does the route end, or does it show a>missed approach escape route, that maybe incorporates a steep>climb/turn. If it does try removing the missed app part and>see if the issue still arises.

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I do notice that the autoland puts the bird down excruatingly hard. My last autoland attempt in the 757-200 was -370ft/min which I feel is a bit excessive. Easily fixable.

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Guest Dashik1

Tried a CAT3 landing agion this morning and it rolled right and I only just cayght it! I'm going to uninstall/reinstall then start paying more attention to whats happening when I land.that way I might be able to provide some more accurate info.The problem only occurs when its at the 50,40,30 callouts if you know what I mean, right about where I would expect the flair.

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Guest Dashik1

OK just to update this.Its all sorted. It turns out a previous poster was right. turning off the wake turbulence in AS6 sorts the problem and CAT3 Autoland's are no porblem now when there set up properly and I get the glideslope from underneath.Thanks for the replys guys.James

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Guest Knikolaes

>OK just to update this.>>Its all sorted. It turns out a previous poster was right. >turning off the wake turbulence in AS6 sorts the problem and>CAT3 Autoland's are no porblem now when there set up properly>and I get the glideslope from underneath.>>Thanks for the replys guys.>>JamesExcellent. Glad you found the issue :-)

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I had posted 2 photos of an aircraft flaring in LFPG autoland, rolled 25 degrees or so to the left 30 feet above the TDZ.It was not due to external disturbance, and the photos posted showed the aircraft controls had commanded the roll. AS6 wake turbulence was off. Believe good news after verifying it.>>OK just to update this.>>>>Its all sorted. It turns out a previous poster was right. >>turning off the wake turbulence in AS6 sorts the problem and>>CAT3 Autoland's are no porblem now when there set up>properly>>and I get the glideslope from underneath.>>>>Thanks for the replys guys.>>>>James>>Excellent. Glad you found the issue :-)

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Guest Knikolaes

>It was not due to external disturbance, and the photos posted>showed the aircraft controls had commanded the roll. AS6 wake>turbulence was off. Believe good news after verifying it.It is verified on some systems. This issue seems to be system related -- otherwise why would only some folks be encountering it and others not. So for some of us it is good news, and believed.Try playing with some settings. You'd be surprised what you might find.maybe i should be more specific and merely reply "Glad you found the issue on your end" . . . Different systems -- different strokes. And mine is a low end system.

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Chris,I previously wrote that I had encountered this behavior on FS2000/2002 Pro with PSS A319/320/321 Pro, AB330, and on FS9/9.1 with PSS AB330, B773ER and B752RR, and those only. No AS was used then on the former FS's, and FSUIPC of various versions only on FS9 if I recall correctly.If it were AS, it should look like an outside disturbance, but the last case I reported is documented well enough to suggest that it is the result of aircraft control input during autoland flare.Regarding the suggestion that it is system related, that could well be, such as an interaction of the above PSS aircraft with the above FS variants. In my words, the PSS control logic used. The older B744 and B777 never did that, which might lead somewhere. Also, I own and fly every conceiveable modern quality FS9 add-on aircraft, but have not seen it there.

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Guest Knikolaes

Same here -- not on the PSS bird, but for other aircraft -- for some reason some aircraft seem a lot more sensative than others. I have a 737 classic that was VERY touchy -- that turned out to be FSUIPC related and the new version of FSUIPC. I have a feeling that something has to be common here with the 757 and I can't help but keep circling to believe it **may** be memory related? Theory?

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Just wanted to add that my account above was previously on 3 Pentium platforms and now an AMD.

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Just did an autoland at kpdx. Winds were calm. I noticed that as soon as I saw the fmc message (which was route ended) the plane started hard bank to left. I had to disconnect the auto pilot to recover. So there maybe a glitch when the fmc route is done, but it doesn't happen all the time.


John K
 

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Guest crosswinds

Ditto John,I had the same issue on approach at OMDB with my 777ER. The aircraft just banked hard right at the "END OF RTE" on the FMC... that was at the threshold of Rwy 12L.There was no follow through missed app routing in the FMC.How can we possibly go about it? Cause after a 12 hour flight fr NY thats the last thing you wanna be left with!- Jay

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