Re: Braking

Date:         23 May 97 09:03:30 
From: (Simon Craig)
Organization: OzEmail Ltd - Australia
References:   1 2 3 4
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>On at least some -- I would have thought many -- aircraft, ground
>spoilers are one of those systems which are not available until the
>WOW (weight-on-wheels) or other ground sensors determine that the
>aircraft is on the ground.  Thus, ground spoilers cannot be part of
>the process you describe on aircraft so designed, unless you were
>only referring to air spoilers (aka speed brakes).

Yes, that is true.  It's a fine definition though. A spoiler is a spoiler.
When the plane is flying they are used as inflight speed brakes, when the
a/c lands the same spoilers (mostly) are used as ground speedbrakes.  On
the 767, the programming changes, thus sending some spoilers up further
than they are able to before the prox switches determines the a/c is "on
the ground."  However, the same spoilers are used whether they are used as
speed brakes in flight or on the ground.

For ground speedbrake operation, all panels are utilised.  For inflight
speedbrake operation, outboard spoilers deploy further up (in degrees) than
the inboards and one spoiler on each wing is locked out.  In addition, all
the spoilers are used for lateral assistance (to improve roll control) when
the control wheel is moved, depending on which wing is to be lifted and
which wing is to be dropped.


Simon Craig

--- I complained because I had no PowerMac; then I met a man who used
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