View Full Version : FMC Descent Forecasts

25th Feb 2002, 11:47
G'day all,

A quick question - How many levels/altitude winds are programmed into the FMC (B747-400 particularly) for the descent phase of flight. (CRZ, A100 & A010??).

Additionally - where is the pilot getting this info from (ACARS/TAFs/TTFs etc...).

Thanks in advance.


25th Feb 2002, 12:11
A pilot at a real airline might get it from his acars, or some other source that is up to date....others get it off the jeppesen flightplan,

25th Feb 2002, 13:33
737-3/4/500: 3 levels of your choice, 'traditionally' Fl200/150/100 but often lower ones not needed where LNAV/VNAV not needed with radar vectoring eg London TMA below FL160.

Normally (in my experience) obtained from forecast winds printed on PLOG. FMC 'knows' cruise wind so that is not needed for descent, and if no winds entered will factor (2/3 of cruise applied at FL200?? I seem to remember).

fast cruiser
25th Feb 2002, 14:44
Fokker 100 descent winds at BMI are generally

FL 240. .FL 180. .FL 100

wind information from LAP 214 for domestic and ICAO charts for outside the UK

26th Feb 2002, 13:22
During descent, if you find that the profile isn't working, or the speed is slowing down, do a direct to current waypoint - the FMC 'sniffs' the surroundings again and recalculates the descent accordingly. Also, make sure all your height constraints are conditional and not hard. Works well on the older 320's.

26th Feb 2002, 14:15
'Tones,. .Take it from an old stager--- whatever you put in, you must know what descent profile you want to fly, and make the aeroplane do it.

Don't become mesmerized by the FMC's, they are just another dumb adding machine, sometimes very dumb.

All the beaut gear is still just an aid to operation, make certain you are flying the aeroplane, and not the aeroplane flying you.

Tootle pip!!

27th Feb 2002, 20:31
Interestingly enough, my flight plan gave me the 5,000ft descent wind going into Bogota (8,500ft!)

Makes you wonder?

28th Feb 2002, 18:44

Could not agree more old boy - far too many of. .the new troops spend too much time messing about. .with the FMC in climb and particuarly the descent. .when they should be flying the airplane and having. .a look out of the window !