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martinlest2

ILS Landings off-centre

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At a depressingly large number of airports (and in good weather, no wind) my otherwise perfect ILS and auto- landings are ruined by the fact that the a/c touches down almost on the grass, on the right-hand edge of the runway. If it were at just the odd airport, I'd assume the AFCAD was off, but it happens at so many, I doubt this. Doesn't seem to matter which a/c I use either.Can anyone suggest a solution? If I do edit the AFCADs, if only as an experiment, what exactly do I do, move the green triangles shown if AFACD2 off to the left a bit? Thank you,Martin

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Hi,If the large green arrow is lined up with the runway in AFCAD, then it is something else in your setup that's causing the problem. Perhaps you have high winds at the airport?But yes, that's how you would alter the ILS trajectory - move the large green arrow.--Tom GibsonCal Classic Propliner Page: http://www.calclassic.comFreeflight Design Shop: http://www.freeflightdesign.comDrop by! ___x_x_(")_x_x___

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If you use the AFCAD progam you can check exactly where the locaiser is and its alignment. If it's at the far end of the runway and aligned with it then it's OK.The only exception is that in real life some localisers are deliberately not aligned with the runway. If you find one like that in FS9 then you need to check the real life charts. My own experience is the Microsoft got it right in the vast majority of cases. For example Nice had an offset localiser when Microsoft froze the data. Since then it's been changed in real life.

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Mystery. The green arrows are perfectly aligned with the runway - and no wind, as I said. I'll have to start counting just how many airports have this problem. It's going to be a real pain troubleshooting this, I think...M

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I recommend using slew mode with a default aircraft (I like the B734). tune the ILS. Slew out to the outer marker or so. Go up/down until the GS is centered (or approximate if LOC only). Now move left/right until CDI needle is centered. Ensure aircraft heading is set to runway heading. Observe runway position from cockpit. Now slew slowly forwardand down keeping the needles centered using left/right as needed. Continue to observe the runway and see if the needles are taking you down the centerline or not. Track the localizer all the way down to the threshold. That should show you that the Localizer is set up properly (in the proper geo position and with the proper angle). If the localizer is guiding you correctly in slew, then the problem most likely is with the autopilot or other aircraft system. You could then try A/P coupled approaches using different aircraft. I guess there could be some problem that affects all aircraft, but I don't know of any, other than possibly a messed up magnetic variation which seems to cause strange problems for aircraft. If the compass systems seem to be correct though I doubt that's the problem.scott s..

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Scott, That was an interesting exercise. I tracked the localiser dead centre all the way to the runway - and it puts me down on the right-hand edge, just off the grass!So, although the ILS green arrow is also dead centre in the AFCAD, I presumably need to shift it slightly to the left to compensate. I'll give it a go anyway,Martin

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With the changed AFCAD I now land on the centre of the runway. But there seem to be SO many airports at which this happens. Just have to be patient and change them as I encounter them I suppose.Thanks again for the idea. (Why didn't I think of it?!!).M. :-)

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