Re: Break the VSI?

Date:         23 Nov 96 03:36:27 
From: (Robert Dorsett)
Organization: Netcom Online Communications Services (408-241-9760 login: guest)
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In article <airliners.1996.2506@ohare.Chicago.COM> writes:
>Yes, they could break the glass. No, it wouldn't help. There are no
>conventional barometric instruments on most modern jet aircraft. The
>data from the static ports and the ram air probes goes into an "air
>data computer". This computer provides an electrical signal that
>drives the instruments. The altimeter and the VSI are not self-contained
>instruments; they only display computer-generated data.

THe standby airspeed and altimeter on the 757 are connected directly to
the pitot-static system.  The regular instruments get their data from the

This is not to imply that going around smashing these instruments would
be a wise or feasible procedure, for many reasons.

Robert Dorsett                         Moderator, sci.aeronautics.simulation