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ahinterl

MD-11 (FS9): Slowdown on descend (2)

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Just for my basic understanding (and because I've experienced different results already):When I descend without doing nothing (full autoflight engaged), should I get the indications on the PFD to lower flaps (i.e. the hollow magenta circles at lower speeds) automatically or do I need to deploy slats or flaps 15 first?In other words: Does the FMS indicate the need for slower speeds regardless of flaps settings or does only e.g. flaps 15 deployment initiate the automatic speed reduction function?As said, I had both scenarios, one where I got the magenta hollow circles when there were no flaps/slats set, and yesterday had a new situation where the FMS didn't indicate me any planned slowdown, even with flaps already set.So, I'm pretty confused what I do wrong...Andreas

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I think you get the ADD DRAG message if the FMC wants you to slow down, at which point you would deploy spoilers or add flaps (if you are close to the airport).I'm a bit confused too, I should spend more time reading the manual.edit: I'm using the FSX version but I assume its the same in FS9... on second reading, I dont think I answered you question anyway :(

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Sometimes speed is managed by the FMC if you're flying a STAR with speed ristrictions. Without speedristrictions I have the following procedure:20 miles from the airport/runway I start extending slats and flaps. At 20 miles slats and after that flaps 15;When the localizer starts to move: flaps 28At 2500 (or a little later): gear downWhen the glidslope indicator starts to move: flaps 35There's no need to worry about adjusting the speed: by extending the flaps, the speeds are automatically reduced to just above the yellow line, so no worries about that. Just by extending flaps you slow down to right speed for final approach.

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Sometimes speed is managed by the FMC if you're flying a STAR with speed ristrictions.
I don't refer to speed restictions in that topic, what I mean is the automatic speed reduction as a function of flaps setting and other factors unknown to me, not based on waypoint constraints, that's two completely different things.
20 miles from the airport/runway I start extending slats and flaps. At 20 miles slats and after that flaps 15;When the localizer starts to move: flaps 28At 2500 (or a little later): gear downWhen the glidslope indicator starts to move: flaps 35
That's fine, but that's the "manual method" of doing things and again has nothing to do with the automatic speed reduction (besides, I lack tables which describe optimum speeds for the different flaps settings...).
There's no need to worry about adjusting the speed: by extending the flaps, the speeds are automatically reduced to just above the yellow line, so no worries about that. Just by extending flaps you slow down to right speed for final approach.
Here we come to the core of what I mean:What exactly triggers the automatic speed reduction: Extending flaps or other components like distance to the destination, speed and altitude etc.?From the answer to this question I can derive whether the FMS plans for automatic speed reduction regardless of flaps settings or not. As I said, I had both situations already and I'm not sure what the normal behaviour of the FMS is intended to be (and as a consequence, I then can look what I made wrong).Andreas

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Just for my basic understanding (and because I've experienced different results already):When I descend without doing nothing (full autoflight engaged), should I get the indications on the PFD to lower flaps (i.e. the hollow magenta circles at lower speeds) automatically or do I need to deploy slats or flaps 15 first?In other words: Does the FMS indicate the need for slower speeds regardless of flaps settings or does only e.g. flaps 15 deployment initiate the automatic speed reduction function?As said, I had both scenarios, one where I got the magenta hollow circles when there were no flaps/slats set, and yesterday had a new situation where the FMS didn't indicate me any planned slowdown, even with flaps already set.So, I'm pretty confused what I do wrong...Andreas
Yes, you should be getting the hollow magenta circles on approach. When I land in KLAX I get the circles at:13.3NM-slats9.3NM-158.3NM-28Outer marker- Gear downWhen gear is down- Flaps 35You can also check out the bottom of this article: http://ops.precisionmanuals.com/wiki/PMDG_MD-11_FAQJames

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Thank you. So, I'm right when I say that at a specific point during autoflight descend/approach, there should be an additional, hollow magenta circle present on the speedtape, situated at a lower speed (and thus indicating the need for flaps)?If so, is it positioned on the tape even if it is within the amber band, and is it drawn below the speed tape if the speed where the indicator is to be placed is out of view?Excuse my "silly" questions, I have no access to my FS PC at the moment, and I like to be "prepared" for my next test session...Andreas

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What exactly triggers the automatic speed reduction: Extending flaps or other components like distance to the destination, speed and altitude etc.?From the answer to this question I can derive whether the FMS plans for automatic speed reduction regardless of flaps settings or not. As I said, I had both situations already and I'm not sure what the normal behaviour of the FMS is intended to be (and as a consequence, I then can look what I made wrong).
I think you didn't do anyting wrong. If you read FMS.60.1 Approach Speeds you can have it both ways: or you extend slats/flaps and the FMS adjusts the speed automatically after they are extended, or you are a little late with your slats/flaps and the FMS indicates that you have to extend slats/flaps to slow down to the desired speed. I think the first procedure should be most common, but in the case you are late or forget the slats/flaps the FMS will remind you.BTW: the FMS will never command a speed below the Vmin with you current flap setting, so FMS speed is never commanded regardless the flap setting.

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