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Through a wide range of nose-low attitudes, a descent
is the only possible condition of flight. The addition of
power at these attitudes will only result in a greater rate
of descent at a faster airspeed.
Through a range of attitudes from very slightly
nose-low to about 30° nose-up, a typical light airplane
can be made to climb, descend, or maintain
altitude depending on the power used. In about the
lower third of this range, the airplane will descend
at idle power without stalling. As pitch attitude is
increased, however, engine power will be required
to prevent a stall. Even more power will be required
to maintain altitude, and even more for a climb. At a
pitch attitude approaching 30° nose-up, all available
power will provide only enough thrust to maintain
altitude. A slight increase in the steepness of climb
or a slight decrease in power will produce a descent.
From that point, the least inducement will result in a
stall.
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4-1
INTRODUCTION
The maintenance of lift and control of an airplane in
flight requires a certain minimum airspeed. This
critical airspeed depends on certain factors, such as
gross weight, load factors, and existing density altitude.
The minimum speed below which further controlled
flight is impossible is called the stalling speed. An
important feature of pilot training is the development
of the ability to estimate the margin of safety above the
stalling speed. Also, the ability to determine the
characteristic responses of any airplane at different
airspeeds is of great importance to the pilot. The
student pilot, therefore, must develop this awareness in
order to safely avoid stalls and to operate an airplane
correctly and safely at slow airspeeds.
SLOW FLIGHT
Slow flight could be thought of, by some, as a speed
that is less than cruise. In pilot training and testing,
however, slow flight is broken down into two distinct
elements: (1) the establishment, maintenance of, and
maneuvering of the airplane at airspeeds and in
configurations appropriate to takeoffs, climbs,
descents, landing approaches and go-arounds, and, (2)
maneuvering at the slowest airspeed at which the
airplane is capable of maintaining controlled flight
without indications of a stall—usually 3 to 5 knots
above stalling speed.
FLIGHT AT LESS THAN CRUISE AIRSPEEDS
Maneuvering during slow flight demonstrates the flight
characteristics and degree of controllability of an
airplane at less than cruise speeds. The ability to
determine the characteristic control responses at the
lower airspeeds appropriate to takeoffs, departures,
and landing approaches is a critical factor in
stall awareness.
As airspeed decreases, control effectiveness decreases
disproportionately. For instance, there may be a certain
loss of effectiveness when the airspeed is reduced from
30 to 20 m.p.h. above the stalling speed, but there will
normally be a much greater loss as the airspeed is
further reduced to 10 m.p.h. above stalling. The
objective of maneuvering during slow flight is to
develop the pilot’s sense of feel and ability to use the
controls correctly, and to improve proficiency in
performing maneuvers that require slow airspeeds.
Maneuvering during slow flight should be performed
using both instrument indications and outside visual
reference. Slow flight should be practiced from straight
glides, straight-and-level flight, and from medium
banked gliding and level flight turns. Slow flight at
approach speeds should include slowing the airplane
smoothly and promptly from cruising to approach
speeds without changes in altitude or heading, and
determining and using appropriate power and trim
settings. Slow flight at approach speed should also
include configuration changes, such as landing gear
and flaps, while maintaining heading and altitude.
FLIGHT AT MINIMUM CONTROLLABLE
AIRSPEED
This maneuver demonstrates the flight characteristics
and degree of controllability of the airplane at its
minimum flying speed. By definition, the term “flight
at minimum controllable airspeed” means a speed at
which any further increase in angle of attack or load
factor, or reduction in power will cause an immediate
stall. Instruction in flight at minimum controllable
airspeed should be introduced at reduced power
settings, with the airspeed sufficiently above the stall to
permit maneuvering, but close enough to the stall to
sense the characteristics of flight at very low
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