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scott967

Sometime too high coming into land when on Glide Slope.. why?

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I am running FSX and flying 737 PIC and Level D 767. I am turning on APP and intercepting the glide slope around 2500. This takes the plane down nicely as I slow down and put flaps and gear down to the setting in the FMC approach ref.In doing all of this I am find that I am coming into the runway lights with 2 red and 2 white, then at about 400-500 ft above the runway they start to get 3 white then 4 white indicating I am too high.At this point at am almost at the landing speed determined in the FMC approach ref so what could be causing this?Do I need to disconnect Autopilot earlier?At what point should I be at my FMC approach speed? Is this as I touch down or on the final?Any ideas as I am landing too far down the runway for comfort.ThanksMark

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Hi,I presume you know how to identify the touchdown point visually (the thick bars on the runway)? Where are you touching down relative to these?If the auto-land simulation is accurate, it will randomize when to flare, so some landing will touch down later than others for the exact same approach conditions.Note also that auto-land in general lands longer than a hand-flown landing will.You can't use the lights during an ILS, as they're for a visual approach, not an instrument approach. You have to watch the GS needle.http://en.wikipedia.org/wiki/VASIBest regards,Robin.

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I agree with OP that the visual PAPI don't seem that accurate. I did an experiment using a random airport -- KMCI RWY 01R.According to the FAA the ILS and PAPI both have 3.00 degree glideslopes. The ILS chart says "VGSI and ILS glidepath not coincident". Further checking shows the ILS Threshold Crossing Height (TCH) for the ILS is 59 ft and the PAPI is 74 ft.I loaded up FSX using the default B738 aircraft. I positioned the aircraft right over the threshold. When the GS needle was centered, the radio altimeter displayed 62 ft. I then looked at the PAPI, and moved the aircraft down until I had a 2 red / 2 white display, and the RA was 35 ft. I think this is common on many approaches.I looked at an aerial photo of the airport and compared it to the default. The PAPI, as displayed in its default position, was about 200m in front of the actual position from the image. Using ADE, I moved the PAPI back about 200 m until it matched the photo location. Then I repeated the experiment.With the PAPI in the new location, I got a 2 red/2 white display between 74 and 65 ft RA -- much better. Still, if the glideslope needle is centered the PAPI will show you off, but this time it will show you low (red). But that's expected per the chart warning.scott s..

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