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Guest NGdriver

FS9 MD11: Descent forecast inop?

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When planning a descent with a strong tailwind i always insert the wind direction\speed in the forecast page but i always end up with overspeed and\or an insane vertical speed. It`s as if the FMS ignores the wind speeds entered when the vertical profile is calculated. Anyone else experience this?RgdsKevin

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Depends on your definition of insane. The descent in the FL30's is usually over 3000 fpm, and I tolerate airspeed excursions better than the FMS and will usually ignore the drag required message if in my judgement I do not have a problem with constraints ahead. The wind forecasts definitely help.

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Depends on your definition of insane. The descent in the FL30's is usually over 3000 fpm, and I tolerate airspeed excursions better than the FMS and will usually ignore the drag required message if in my judgement I do not have a problem with constraints ahead. The wind forecasts definitely help.
Yes i should have been more clear. I get vertical speeds in excess of -4500 fpm and almost always end up with a drag required message later on. To me it seems as the transition between cruise and descent is too "steep" if you know what i mean. The A\P waits too long before starting the descent and overshoots it by a few houndred feet and thus ends up diving for the profile. Well, these are just my observations but i have definitely seen smoother descents.
Depends on your definition of insane. The descent in the FL30's is usually over 3000 fpm, and I tolerate airspeed excursions better than the FMS and will usually ignore the drag required message if in my judgement I do not have a problem with constraints ahead. The wind forecasts definitely help.
Yes i should have been more clear. I get vertical speeds in excess of -4500 fpm and almost always end up with a drag required message later on. To me it seems as the transition between cruise and descent is too "steep" if you know what i mean. The A\P waits too long before starting the descent and overshoots it by a few houndred feet and thus ends up diving for the profile. Well, these are just my observations but i have definitely seen smoother descents.

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Depends on your definition of insane. The descent in the FL30's is usually over 3000 fpm, and I tolerate airspeed excursions better than the FMS and will usually ignore the drag required message if in my judgement I do not have a problem with constraints ahead. The wind forecasts definitely help.
Yes i should have been more clear. I get vertical speeds in excess of -4500 fpm and almost always end up with a drag required message later on. To me it seems as the transition between cruise and descent is too "steep" if you know what i mean. The A\P waits too long before starting the descent and overshoots it by a few houndred feet and thus ends up diving for the profile. Well, these are just my observations but i have definitely seen smoother descents.

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Kevin, are you using ECON or POLICY? The ECON is much better in this context and I have it selected in the options menu. In other words, the MD11 is superior to the Boeings in it's handling of descents but you have to let it do the PROF calculations and give it the info it needs. 4500 fpm is not insane under some conditions although it is higher than expected but in the higher +36FLs it takes a significant v/s rate to get on profile due to the very high GS values, the key indicator is the amount of deviation you are seeing on the vertical profile guage that shows up on the ND during descent. If you are too high and the indication above the altimeter tape on the PFD says IDLE DESCENT then it is having a hard time keeping on the profile and maybe the tailwinds are higher than forecast. As long as the vertical deviation from profile is small an occasional DRAG REQUIRED message is not cause for corrective action... note I said occasional.

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