Flight Three
Flight Three will introduce you to
operating the airplane in different configurations and at slow airspeeds. You
will also learn how to recover from stalls, develop some awareness of spins,
and learn how to perform steep turns.
Before commencing Flight Three be sure to do a thorough Preflight
inspection. The airplane used for this flight is a Cessna
152.
Using the techniques developed in Flights One and
Two proceed to the practice area.
Select a location where you will be able to maneuver without disturbing people
on the ground and where you could land in the event of an emergency. Select an
altitude such that at no point during the maneuvers you are less than 1,500
feet above the ground.
Before doing any maneuvers clear the area by reversing course or making two
ninety degree changes of heading.
Flight at Minimum Controllable Airspeed
More
detail
The first maneuver will involve flying the airplane at Minimum Controllable
Airspeed (MCA).
This will enable you to learn how the controls feel and how the airplane
performs at slow airspeeds. To achieve minimum controllable airspeed you will
need to put the airplane into the landing configuration. Your instructor will
demonstrate the maneuver prior to you practicing.
Having cleared the area select your altitude and heading and reference your
position with respect to outside visual references.
Apply carburetor heat, reduce power to 1500rpm and gradually apply back
pressure to the control wheel to reduce airspeed but maintain altitude. Keep
your wings level as you do this.
Once the airspeed is in the flap operating range (in the white arc on the
airspeed indicator) lower the flaps in ten degree increments.
As the airspeed diminishes you will reach a point where it will be necessary to
add power to maintain altitude. As you add power you will need to apply some
right rudder to counteract the left turning forces that become more apparent at
slow airspeeds and high power settings. Carburetor heat should be off once the
power is back in the green arc on the tachometer.
You will now be flying along with a nose high attitude and an airspeed about
five knots above stall speed (Vso). The controls will feel mushy and the stall
warning horn will be sounding in the background. In this configuration the
airplane is experiencing a lot of drag and even a large increase in power
setting will barely result in a climb.
Hence it is apparent that if one allows the airspeed to get too slow the
airplanes climb performance will diminish significantly. Also note how much
more difficult it is to precisely control the airplane at very slow airspeeds.
The only time the airplane gets this slow during normal operations is during
the final seconds of flaring to land. Therefore you can see that if you decided
not to land at the last moment you would need to apply full power and increase
your airspeed before the airplane will start to climb. This procedure is known
as a go around and is very similar to the recovery from this demonstration of
MCA.
To return to normal flight from MCA apply full power (carburetor heat off) and
slightly lower the nose to regain airspeed. Retract the flaps to twenty
degrees. Gradually retract flaps to ten degrees and once a positive rate of climb
and best rate of climb speed (Vy) are established retract flaps to zero
degrees. Return to straight and level flight and reduce power to a cruise
setting.
Having experienced flight at MCA whilst flying straight you will then practice
turns and climbs and descents in this configuration. You will soon discover
that you will need to apply some extra power to maintain altitude whilst you
turn. You will also find that even a large application of power will result in
only a minimal rate of climb as you are operating on the back side of the power
curve.
Currently the Private Pilot Practical Test Standards (PTS) do not mention
flight at MCA. However they do require you to maneuver during slow flight in a
configuration as specified by the examiner. This could be the landing
configuration in which case you will be expected to stabilize the airspeed at
1.2 times the stall speed in the landing configuration.
Slow Flight
The next maneuver your instructor
will demonstrate is slow flight in the clean (flaps up) configuration.
As with all maneuvers clear the area by making turns to look for traffic before
starting the demonstration.
Having cleared the area select your altitude and heading and reference your
position with respect to outside visual references.
Apply carburetor heat, reduce power to 1500rpm and gradually apply back
pressure and the control wheel to reduce airspeed but maintain altitude. Keep
your wings level as you do this.
As the airspeed diminishes you will reach a point where you will no longer be
able to maintain altitude by pitch alone. At this point add power as necessary
to maintain altitude. As you add power you will also need to apply some right
rudder to counteract the airplanes tendency to turn left.
You will be flying with a nose high attitude slightly above stall speed (1.2 x
Vs is specified in the practical test standards) the controls will feel mushy
and you may hear the stall warning horn in the background.
To return to normal flight from slow flight simultaneously slightly lower the nose
and apply full power (carburetor heat off) . Having stabilized the airplane in
straight and level flight reduce power to a cruise setting.
Having experienced slow flight whilst maintaining heading and altitude you will
then practice turning, climbing and descending whilst in this configuration.
Once you have developed a feel for operating the airplane at critically low
airspeeds by practicing flight at MCA and slow flight you are ready to move on
to learning how to recognize and recover from stalls.
Stalls
A stall
is an aerodynamic phenomenon in which the smooth flow of air over the airplane’s
wing (or any airfoil) separates and becomes disrupted
resulting in a dramatic decrease in lift.
For any particular wing (or airfoil) there is a specific angle of attack
at which a stall will always occur. This is known as the critical
angle of attack. The critical angle of attack can be attained at any airspeed,
power setting or attitude. Hence a stall can occur at any airspeed, power
setting, or attitude. In training
situations stall recoveries are generally practiced at low airspeeds and with
nose high attitudes. However you must be aware that stalls can also occur
at high airspeeds or even in nose low attitudes if the critical angle of attack
is exceeded. The angle of attack is the angle between the chordline
of the wing and the relative wind. The fundamental
key to all stall recoveries is to reduce the angle of attack so that the critical
angle of attack is no longer exceeded.
(ANGLE OF ATTACK DIAGRAM)
Power-Off Stall
Select a location where you will be able to maneuver without disturbing people
on the ground and where you could land in the event of an emergency. Select an
altitude such that at no point during the maneuvers you are less than 1,500
feet above the ground.
The first stall your instructor will demonstrate is the power-off stall. This
is sometimes referred to as an approach to landing stall and is performed in
the landing configuration.
Having cleared the area select your altitude and heading and reference your
position with respect to outside visual references.
Apply carburetor heat, reduce power to 1500rpm and gradually apply back
pressure to the control wheel to reduce airspeed but maintain altitude. Keep
your wings level as you do this.
Once the airspeed is in the flap operating range (in the white arc on the
airspeed indicator) lower the flaps in ten degree increments. Having deployed
full flaps reduce the power to idle.
Continue to pitch to reduce airspeed and maintain altitude. As you get close to
stalling the controls will get mushy, the stall warning horn will sound, and
you may feel buffeting as the airflow over the wings deteriorates. The stall
occurs when the critical angle of attack is reached and the airflow breaks away
from the upper surface of the wing. At this point the wings will no longer be
producing lift and the nose will start to drop.
To recover simply reduce the angle of attack by lowering the nose (as you will
have been pulling back to induce the stall you simply need to relax the back
pressure) whilst simultaneously applying full power(carburetor heat off).
Retract the flaps to 20 degrees and then gradually retract them to 10 degrees
and once a positive rate of climb and best rate of climb (Vy) airspeed have
been obtained retract them to zero degrees.
As you add power remember to apply some right rudder to keep coordinated.
If at the moment when the airplane stalls the nose moves to one side (yaws)
apply the opposite rudder to counteract the yaw. Resist the temptation to use
ailerons to level the wings until you are no longer stalled.
On completion of the recovery return to straight and level flight and a cruise
power setting.
You will notice that the initial set up and recovery from the power-off stall
is very similar to the set up and recovery from flight at Minimum Controllable
Airspeed(MCA).
A common mistake when recovering from stalls is to lower the nose too much and
hence losing more altitude from the resulting dive than from the stall itself.
It is only necessary to lower the nose enough to reduce the angle of attack to
less than the critical angle of attack. This usually means it is not necessary
to lower the nose below the horizon. By initially pitching for the best angle
of climb speed (Vx) and than transitioning to best rate of climb speed (Vy)
loss of altitude can be minimised.
Having learnt how to recognize and recover from a power-off stall your next
maneuver will be the power-on stall. This is procedurally simpler than the
power-off stall but more dramatic to experience in that the entry occurs with
full power and a significantly nose high attitude. Your instructor will
demonstrate before you practice.
Having cleared the area select your altitude and heading and reference your
position with respect to outside visual references.
Apply carburetor heat, reduce power to 1500rpm and gradually apply back
pressure to the control wheel to reduce airspeed but maintain altitude. Keep
your wings level as you do this.
Once you have slowed the airplane to approximately rotation speed (the speed at
which you start to raise the nose during the takeoff roll, 50 KIAS in the
Cessna 152) apply full power and continue to pitch up so that the airspeed
continues to diminish. Remember to apply right rudder to counteract the left
turning tendency. As you pitch and approach the stall the controls will become
mushy, the stall warning horn will start to sound and you may feel some
buffeting as the critical angle of attack is reached and the airflow breaks
away from the wings.
To recover simply reduce the angle of attack by lowering the nose (as you will
have been pulling back to induce the stall you simply need to relax the back
pressure). You already have full power and flaps up.
If at the moment when the airplane stalls the nose moves to one side (yaws)
apply the opposite rudder to counteract the yaw. Resist the temptation to use
ailerons to level the wings until you are no longer stalled.
! If the nose drops off to one side
as you stall it’s important to resist your natural tendency to level the wings
using ailerons and instead use opposite rudder to
counteract yaw. Chances are the first time the nose
drops off to one side you will instinctively turn the control wheel in the
opposite direction in a vain attempt to level the wings. If the wings are not
too deeply stalled you may get away with this but in general it is a bad idea
which could aggravate the stall to the extent that you end up in a spin. This is
because the aileron movement will increase the angle of attack and drag on the
downward moving wing and result in a more complete stall and greater loss of
lift so the low wing goes down even more relative to the high wing.
On completion of the recovery return to straight and level flight and a cruise
power setting.
Initially you will practice stall recoveries whilst flying straight. Once you
have built up your confidence your instructor will have you try them whilst
turning during the entry. By doing this you will discover the importance of
remaining coordinated and that the airplane will stall at a higher speed when
turning (due to greater wing loading).
During normal flight operations you should not be flying at angles of attack
high enough to result in stalls. However an ability to recognise the
aerodynamic indications of an oncoming stall and to recover from stalls is
required in the practical test and is an essential skill for any pilot to have
in order to avoid or recover from abnormal situations.
Spin Awareness
Although private pilots are no
longer required to demonstrate spin recovery techniques as part of the
practical test it is important for all pilots to be aware of how spins can
occur and to be familiar with standard recovery techniques. A spin is an
aggravated stall that results in autorotation involving a rapid descent in a
corksrew path.
Number one way to avoid spins is
to avoid stalls. You have to stall to spin. You will not stall if you do not
exceed the critical angle of attack. Unfortunately for those of us whose
airplanes are not equipped with angle of attack indicators (which is just about
all of us except military and aerobatic pilots) we have to rely on maintaining
normal airspeeds and attitudes to avoid stalls.
Number two way to avoid spins is
to avoid uncoordinated flight. Keeping the ball centered in the inclinometer at all times will greatly reduce the
possibility of a wing dropping and a spin developing if you stall.
Third way to avoid spins is to
maintain directional control of the airplane if it stalls by using opposite
rudder to prevent the nose from yawing towards a descending wing and promptly
recover from any stall before a spin can develop.
However if in spite of all these
precautions you find yourself in a spin the standard recovery is as follows.
However be sure to refer to the FAA approved flight manual for the airplane you
are flying to ensure you are familiar with the recommended technique for your
airplane.
Spin Recovery
This procedure is not generally practiced unless accompanied by an experienced instructor in an appropriately certified airplane. It is essential you refer to the flight manual for your airplane and learn the technique for your specific airplane. The following is a common example of a recovery technique.
Close throttle and apply full
rudder in the opposite direction to the spin.
When rotation slows, apply brisk,
positive straight forward movement of the elevator control (forward of the
neutral position). Hold the controls in this position and as the rotation stops
neutralize the rudder. Once the rotation has stopped and the rudder has been
neutralized apply back pressure on the elevator to gradually raise the nose to
level flight.
(SPIN RECOVER ANIMATION OR
DIAGRAMS LIKE FLIGHT TRAINING MANUAL)
The final new skill your instructor will demonstrate for this flight is steep
turns.
Steep Turns
More detail
Having cleared the area select your altitude and heading and reference your
position with respect to outside visual references.
Establish straight and level flight at the airplanes recommended entry speed
which should be at or below maneuvering speed (Va). For the Cessna 152 steep
turns are usually entered at 95 KIAS. This will require a power setting in the
region of 2300 rpm.
Check for traffic just before rolling into the turn and assertively bank the
airplane to establish 45 degrees of bank. As you establish the bank apply a
little extra back pressure and power to help maintain altitude in the turn .
Reference the position of the nose with respect to the horizon and imagine you
are drawing a straight line parallel to the horizon with the nose of the
airplane. The objective is to maintain constant altitude whilst maintaining 45
degrees of bank and to roll out on the entry heading. In order to roll out on
your entry heading lead the roll out by approximately half your angle of bank.
As you roll out you will need to apply some forward pressure on the control
wheel and once you are back in straight and level flight adjust the power to a
cruise setting.
When demonstrating steep turns be careful not to exceed the recommended
airspeed and bank angle. As the bank angle increases beyond 45 degrees
substantial additional load is imposed on the airplane and most trainers are
only designed to withstand 3.8 gs. Also avoid getting too slow since stall
speed increases with bank angle since it is related to load factor.
Practice steep turns both to the left and right being careful to check for
traffic before commencing any turns.
This will complete the new material for Flight Three. Return to base and go
over the new procedures on the ground. You may decide with your instructor to
practice these skills some more before moving on to the new items in Flight
Four.
First Flight online lessons are not a substitute for study of the Pilots Operating Handbook/Airplane Flight Manual for the airplane you intend to fly. It is essential you refer to the Pilots Operating Handbook/Airplane Flight Manual for the airplane you intend to fly for the procedures and checklists that currently apply to your airplane.
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