Crab, slips, and crossed controls

On Mon, 22 Sep 2008 14:10:50 GMT, Robert Moore
wrote:

Stealth Pilot wrote
Sideslips are a very useful tool because they allow you to
substantially increase the drag, which makes you descent like a
plumbers toolbag, but doesnt change the forward speed. so you have no
increased risk of stalling as you wash off the height.

What you have described is the "forward slip". Although control usage
is the same in both, a "side slip" is used to correct for a crosswind,
and a "forward slip" is used to descend more rapidly on final without
having the airspeed increase. If one is not landing, I suppose that it
would just be a "slip".

Airliners normally do not use either because of the increased discomfort
caused the passengers....both being uncoordinated flight.

Amine wrote:
PS: I have read about many cases of jetliners that had to make
emergency descents at abnormally high speeds, but the AC143 seems the
only one to have used the sideslip.

AC 143 was constrained by "touchdown speed" runway length. An "emergency
descent" has no such constraint and therefore is able to use the
aircraft's maximum certificated speed for the descent...far in excess of
what would be possible in an approach/landing situation.

In an engine failure situation, keep it as high as possible for as long
as possible to insure that the field can be reached, and then slip as
much as required to lose the excess altitude without gaining airspeed.

Bob Moore
Flight Instructor ASE-IA
ATP B-707 B-727
PanAm (retired)

in my country the manouver I describe is always called a side slip.

side slips are used as I indicate to dirty up the aircraft
aerodynamically.
they can be used to counter a crosswind but the crabbed approach is
preferred because it doesnt change the approach profile.

it is a side slip.

youalls mileage may vary :-)

Stealth Pilot