Re: Rate of climb and descent

Date:         11 Feb 98 04:26:26 
From:         "Chris Dahler" <dahler@iglobal.net>
Organization: Internet Global Services, Inc
References:   1
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>I wonder what would be typical rates of climb and descent for airliners.
>I suppose standard procedures provide for low figures in order to try to
>make the ride as smooth as possible for the passengers. I also would
>like to know what are the limit rates in both cases. I mean, for a twin
>engine aircraft like the 767, "almost empty" (i.e. no passengers/load
>and a small amount of fuel) does the climb rate exceed 5000 fpm? For the
>same 767 fully loaded, spoilers on, etc, would be the figure similar to
>this (downwards)? It does not to be a 767. I just would like to have an
>idea on the subject.

There are no "limits" as such to rates of climb and descent; you are only
limited by the power available, the efficiency of the wing, and the weight
of the aircraft.  Typically, lightly loaded twin jet modern airliners will
easily exceed 5000 fpm; the vertical speed indicator stops at 6000 fpm, but
once this instrument is pegged there's no telling how fast you are going up.

Descent rates are quite a bit lower.  Due to the increasing efficiency of
modern wing designs, modern aircraft do not want to come down in a hurry.
The limiting factor here is airspeed.  Speed brakes help, but not much.  You
can start a descent at 35,000 feet or so by going to 4000 to 6000 fpm, but
as you get into the mid-20,000 feet range, you'll have to back that off to
around 3000 to 3500 at the most or you'll exceed design airspeed limits.

Chris Dahler