Stefan wrote
A slip is a slip is a slip.
I always wondered why so many flight instructors celebrate the art of
making simple things seem complicated. I finally came to the conlusion
that it's to look more impressive to the female students.

From The FAA H-8083-3a, Airplane Flying Handbook

INTENTIONAL SLIPS
A slip occurs when the bank angle of an airplane is too
steep for the existing rate of turn. Unintentional slips
are most often the result of uncoordinated
rudder/aileron application. Intentional slips, however,
are used to dissipate altitude without increasing airspeed,
and/or to adjust airplane ground track during a
crosswind. Intentional slips are especially useful in
forced landings, and in situations where obstacles must
be cleared during approaches to confined areas. A slip
can also be used as an emergency means of rapidly
A slip is a combination of forward movement and
sideward (with respect to the longitudinal axis of the
airplane) movement, the lateral axis being inclined
and the sideward movement being toward the low
end of this axis (low wing). An airplane in a slip is in
fact flying sideways. This results in a change in the
direction the relative wind strikes the airplane. Slips
are characterized by a marked increase in drag and
corresponding decrease in airplane climb, cruise, and
glide performance. It is the increase in drag, however,
that makes it possible for an airplane in a slip to
descend rapidly without an increase in airspeed.

A“sideslip” is entered by lowering a wing and applying
just enough opposite rudder to prevent a turn. In a
sideslip, the airplane’s longitudinal axis remains parallel
to the original flightpath, but the airplane no
longer flies straight ahead. Instead the horizontal
component of wing lift forces the airplane also to
move somewhat sideways toward the low wing.
[Figure 8-12] The amount of slip, and therefore the
rate of sideward movement, is determined by the bank
angle. The steeper the bank—the greater the degree of
slip. As bank angle is increased, however, additional
opposite rudder is required to prevent turning.

A “forward slip” is one in which the airplane’s
direction of motion continues the same as before the
slip was begun. Assuming the airplane is originally
in straight flight, the wing on the side toward which
the slip is to be made should be lowered by use of the
ailerons. Simultaneously, the airplane’s nose must be
yawed in the opposite direction by applying opposite
rudder so that the airplane’s longitudinal axis is at an
angle to its original flightpath. [Figure 8-13] The
degree to which the nose is yawed in the opposite
direction from the bank should be such that the
original ground track is maintained. In a forward slip,
the amount of slip, and therefore the sink rate, is
determined by the bank angle. The steeper the bank—
the steeper the descent.

Rgds Bob Moore