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By: Paul "BJ"
Ransbury, Chief Pilot
APS Emergency Maneuver
TrainingQualifications
and Experience:
USA/Canada: ATP, Single/Multi-Engine
IFR
USA: CFI / CFII / MEI / AGI
Canada: Class 1 Aerobatic
Flight / Ground Instructor
FAA - Aviation Safety Counselor
Memberships: IAC, EAA, ICAS,
NAFI
ICAS Certified Level 1 Air
Show Performer
Military: F-18 Fighter Pilot
/ Fighter Weapons Instructor
Graduate
Airlines: Airbus A320 Pilot
Extra 300L Unlimited Aerobatic
Aircraft: 2000+ Hours
BSc. Honors Mathematics and
Physics |
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The Incipient Spin is
a term assigned to the transition phase during which a stall is
propagating towards a developed spin. The recovery from an incipient
spin prior to reaching one-turn is shown in the video
below. This
is for demonstration purposes only and should
only be attempted in a spins-approved aircraft.
Our goal as a pilot when
faced with a stall, including slipping or skidding cross-controlled
and accelerated stalls, is to immediately and correctly apply the Stall
Recovery Procedure. The application of the Stall Recovery
Procedure is our first line of defense in recovering the aircraft to
normal flight (i.e. Angle of Attack (AOA) less than Critical AOA).
If the aircraft is uncoordinated at the stall and this yaw-roll
couple / uncoordination is allowed to develop while sustaining the
stall, the aerodynamics being experienced by the aircraft will
eventually drive the aircraft towards a different stabilized flight
condition called The Spin. We need to stop the spin before it starts
and the Stall Recovery Procedure is how to do it.
Although every stall
does not result in a spin, it is important to recognize that
every spin is always preceded by a stall. If we can "fix" the
stall when it starts, we save ourselves the drama of having to
deal with the spin. Note: Once in a developed spin, the
aircraft will not respond favorably to the Stall Recovery
Procedure. When faced with a developed spin the pilot should
immediately apply the Spin Recovery Technique in the hopes of
recovering from the spin, if it is recoverable at
all. |
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At what point do we make the
decision to stop applying the stall recovery and revert to the spin
recovery? That is an excellent question and the answer really
depends upon the type, category and stall characteristics of the
aircraft in question. For example, normal and utility single-engine
certified aircraft must demonstrate recoverability from a one-turn
spin (or a 3-second spin, whichever takes longer) in not more than
one additional turn, but that's it. After one-turn, there is no
guarantee the aircraft is recoverable at all unless it is certified
for spins. The vast majority of large multi-engine aircraft are not
recoverable from the spin because the pro-spin inertial forces
generated in the developed spin for these aircraft exceed the
pilot's ability to generate sufficient anti-spin force to
"de-couple" auto-rotation to return to normal flight. In these
aircraft, it may be that the only option available is the Stall
Recovery Procedure and the only portion of the stall that offers a
recovery option is the initial stage. The earlier the Stall Recovery
Procedure is correctly applied in the stall, the more likely the
possibility of a recovery.
STALL RECOVERY PROCEDURE
An example of a stall
recovery for most general aviation aircraft and most other aircraft
types and classes is as follows:
1. PUSH: Reduce AOA (forward
movement of the control column) to allow the wing to reduce AOA
below critical AOA, reduce drag and to immediately transition from
stalled fight to normal unstalled flight. Common tendencies are to
either over-push causing excess nose drop below the horizon
increasing altitude loss or a fore-aft pumping motion of the yoke
causing one or more secondary stalls.
2.
POWER: Smoothly add up to full power
(usually) to increase
airspeed and minimize altitude loss. We can do stall recoveries
all day with the power at idle, however, an idle power setting is
not assisting us in minimizing altitude loss.
Keep in mind that there are certain situations
that selecting power to idle in the stall
recovery is the proper action. Examples include
high-torque single-engine prop aircraft and in a
Vmc situation in a multi-engine aircraft.
3.
RUDDER: If there is any roll/yaw motion associated with
the initial stall and the wing is still at or beyond critical AOA,
the rudder should be used to stop the yaw-roll couple from
developing. The amount of rudder used is only enough to coordinate
the flight condition and should be accomplished in one
application. Pumping or cycling the rudder is not a desirable
technique especially for large aircraft. Note that the rudder is
not used to roll the aircraft wings-level in a stall recovery.
Common errors in the use of rudder vary from not using it all to
using it far too much, for too long. Rudder is critically
important in an uncoordinated stall condition (such as a
cross-controlled stall) to ensure the stall is not allowed to
develop from a stall to a spin.
4. ROLL: When the wings are clearly unstalled and
coordinated flight has been regained. The aircraft's flight
attitude must be immediately be re-oriented to a wing's level
condition by rolling with aileron and coordinated rudder to the
nearest horizon. Again, the aircraft should not be rolled by use
of rudder alone at this stage. The primary roll control in normal
flight is through the proper use of ailerons.
5.
CLIMB: With the wings level in coordinated flight, aft
yoke movement should be immediately applied to initiate recovery
to a climbing attitude. The amount of elevator movement applied
must ensure the aircraft remains below critical AOA at speeds
below Va and at a load less than the limited load factor of the
aircraft at speeds above Va.
Essentially, the first three
steps of the stall recovery (1-2-3) are directly focused on safely
recovering the aircraft from the stall and the last two steps (4-5)
are to recover from any resulting unusual attitude. It is important
for the pilot know and understand that these processes can not be
successfully reversed. The stall must be solved first, regardless of
the flight attitude of the aircraft, then followed by solving the
unusual attitude.
Please take a moment to have a look at
the demonstration below to see how the Stall Recovery effectively
recovers the aircraft prior to completing one-turn of rotation from
a cross-controlled slipping turn stall entry.
This only applies to a Normal category aircraft
(and should only ever be attempted in a
Spins-Approved aircraft such as and Aerobatic
aircraft) - emphasis in all practical training
should be for the stall recovery to be applied
at the first indication of the stall in all
aircraft. If you prefer to look
at a more detailed discussion on the recovery from a skidded turn
stall entry, then please refer to our newsletter on the Skidded Turn Traffic Pattern Stall. In the
meantime, please have a look at this one ... we look forward to
hearing your comments in the form below.
The Incipient Spin
The "HIGH"
Resolution Video Format Yields Best Video and
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