Crab, slips, and crossed controls

"Stealth Pilot" wrote in message
...
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

The slips are named for their flight path in relation to a point on the
ground. The forward slip, when used in relation to a runway, creates a
direct forward path to the end of the runway. This is accomplished by
lowering a wing and opposite rudder at the same time. The nose of the
aircraft is to the left or right of the runway heading but the flight path
is directly forward toward the runway. The primary use of this slip is to
lose altitude without increasing airspeed and also to allow a view of the
runway if the front windshield is obstructed with ice or oil. The side
slip, when used in relation to a runway, creates a sideways flight path .
This is accomplished by lowering a wing and using rudder to keep the nose of
the aircraft pointed straight down the runway. In a no-wind situation the
aircraft will move sideways left or right of the runway centerline depending
on which wing is lowered. The primary use of this slip is to counteract
side drift in a crosswind landing and allow the aircraft to touchdown
parallel to the runway centerline.

--

*H. Allen Smith*
WACO - We are all here, because we are not all there.