Flying Handbook Menu > Slow Flight, Stalls, and Spins > Stalls > Accelerated Stalls
Though the stalls just discussed normally occur
at a specific airspeed, the pilot must thoroughly understandthat
all stalls result solely from attempts to fly at excessively
high angles of attack. During flight, the angle of attack of
an airplane wing is determined by a number of factors, the most
important of which are the airspeed, the gross weight of the
airplane, and the load factors imposed by maneuvering.
At the same gross weight, airplane configuration,
and power setting, a given airplane will consistently stall
at the same indicated airspeed if no acceleration is involved.
The airplane will, however, stall at a higher indicated airspeed
when excessive maneuvering loads are imposed by steep turns,
pull-ups, or other abrupt changes in its flightpath. Stalls
entered from such flight situations are called “accelerated
maneuver stalls,” a term, which has no reference to the
Stalls which result from abrupt maneuvers tend
to be more rapid, or severe, than the unaccelerated stalls,
and because they occur at higher-than-normal airspeeds, and/or
may occur at lower than anticipated pitch attitudes, they may
be unexpected by an inexperienced pilot. Failure to take immediate
steps toward recovery when an accelerated stall occurs may result
in a complete loss of flight control, notably, power-on spins.
This stall should never be practiced with wing
flaps in the extended position due to the lower “G”
load limitations in that configuration.
Accelerated maneuver stalls should not be performed
in any airplane, which is prohibited from such maneuvers by
its type certification restrictions or Airplane Flight Manual
(AFM) and/or Pilot’s Operating Handbook (POH). If they
are permitted, they should be performed with a bank of approximately
45°, and in no case at a speed greater
than the airplane manufacturer’s recommended
airspeeds or the design maneuvering speed specified for the
airplane. The design maneuvering speed is the maximum speed
at which the airplane can be stalled or full available aerodynamic
control will not exceed the airplane’s limit load factor.
At or below this speed, the airplane will usually stall before
the limit load factor can be exceeded. Those speeds must not
be exceeded because of the extremely high structural loads that
are imposed on the airplane, especially if there is turbulence.
In most cases, these stalls should be performed at no more than
1.2 times the normal stall speed.
The objective of demonstrating accelerated
stalls is not to develop competency in setting up the stall,
but rather to learn how they may occur and to develop the ability
to recognize such stalls immediately, and to take prompt, effective
recovery action. It is important that recoveries are made at
the first indication of a stall, or immediately after the stall
has fully developed; a prolonged stall condition should never
An airplane will stall during a coordinated
steep turn exactly as it does from straight flight, except that
the pitching and rolling actions tend to be more sudden. If
the airplane is slipping toward the inside of the turn at the
time the stall occurs, it tends to roll rapidly toward the outside
of the turn as the nose pitches down because the outside wing
stalls before the inside wing. If the airplane is skidding toward
the outside of the turn, it will have a tendency to roll to
the inside of the turn because the inside wing stalls first.
If the coordination of the turn at the time of the stall is
accurate, the airplane’s nose will pitch away from the
pilot just as it does in a straight flight stall, since both
wings stall simultaneously.
An accelerated stall demonstration is entered
by establishing the desired flight attitude, then smoothly,firmly,
and progressively increasing the angle of attack until a stall
occurs. Because of the rapidly changing flight attitude, sudden
stall entry, and possible loss of altitude, it is extremely
vital that the area be clear of other aircraft and the entry
altitude be adequate for safe recovery.
This demonstration stall, as in all stalls,
is accomplished by exerting excessive back-elevator pressure.
Most frequently it would occur during improperly executed steep
turns, stall and spin recoveries, and pullouts from steep dives.
The objectives are to determine the stall characteristics of
the airplane and develop the ability to instinctively recover
at the onset of a stall at other-than-normal stall speed or
flight attitudes. An accelerated stall, although usually demonstrated
in steep turns, may actually be encountered any time excessive
back-elevator pressure is applied and/or the angle of attack
is increased too rapidly.
From straight-and-level flight at maneuvering
speed or less, the airplane should be rolled into a steep level
flight turn and back-elevator pressure gradually applied. After
the turn and bank are established, back-elevator pressure should
be smoothly and steadily increased. The resulting apparent centrifugal
force will push the pilot’s body down in the seat, increase
the wing loading, and decrease the airspeed. After the airspeed
reaches the design maneuvering speed or within 20 knots above
the unaccelerated stall speed, back-elevator pressure should
be firmly increased until a definite stall occurs. These speed
restrictions must be observed to prevent exceeding the load
limit of the airplane.
When the airplane stalls, recovery should be
made promptly, by releasing sufficient back-elevator pressure
and increasing power to reduce the angle of attack. If an uncoordinated
turn is made, one wing may tend to drop suddenly, causing the
airplane to roll in that direction. If this occurs, the excessive
backelevator pressure must be released, power added, and the
airplane returned to straight-and-level flight with coordinated
The pilot should recognize when the stall is
imminent and take prompt action to prevent a completely stalled
condition. It is imperative that a prolonged stall, excessive
airspeed, excessive loss of altitude, or spin be avoided.