Stalls and Spin Awareness
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OBJECTIVE: To identify the conditions leading to stalls, recognize when a stall occurs and provide appropriate corrective action
ELEMENTS:
A. Aerodynamics of power-off stalls. B. Aerodynamics of power-on stalls C. Relationship of various factors such as landing gear and flap configuration, weight, center of gravity, load factor, and bank angle to stall speed. D. Flight situations where unintentional power-off stalls may occur. E. Flight situations where unintentional power-on stalls may occur. F. Recognition of the first indications of power-on stalls. G. Recognition of the first indications of power-off stalls. H. Performance of power-off stalls in descending flight (straight or turning). I. Performance of power-on stalls in climbing flight (straight or turning). J. Entry technique and minimum entry altitude. K. Coordination of flight controls. L. Recovery technique and minimum recovery altitude.
SCHEDULE: Pre-flight instruction: 15 Minutes Travel to training area: 10 Minutes Instructor Demonstration: 15 Minutes Student Practice: 30 Minutes Return from practice area: 10 minutes Post-flight Review: 20 Minutes Total Time: 1:40
EQUIPMENT: Functional aircraft.
INSTRUCTOR’S ACTIONS: A. Conduct preflight stall training, explain stalls and the relationship of spins to stalls. B. Ensure the area is clear prior to conducting maneuver. C. Demonstrate power off stall, power on stall, turning stall. D. Conduct post flight briefing.
STUDENT’S ACTIONS: A. Ask questions, review homework. B. Perform preflight. C. Observe demonstrations. D. Perform stalls IAW PTS.
COMPLETION CRITERIA: Student performs stalls with minimum loss of altitude while maintaining entry heading +/- 10 degrees.
COMMON ERRORS: A. Power-Off Stalls.
1. Failure to establish the specified landing gear and flap configuration prior to entry. 2. Improper pitch, heading and bank control during straight ahead stalls. 3. Improper pitch and bank during turning stalls. 4. Rough or uncoordinated control technique. 5. Failure to recognize the first indications of a stall. 6. Failure to achieve a stall. 7. Improper torque correction. 8. Poor stall recognition and delayed recovery. 9. Excessive altitude loss or excessive airspeed during recovery. 10. Secondary stall during recovery.
B. Power-On Stalls
1. Failure to establish the specified landing gear and flap configuration prior to entry. 2. Improper pitch, heading and bank control during straight ahead stalls. 3. Improper pitch and bank during turning stalls. 4. Rough or uncoordinated control technique. 5. Failure to recognize the first indications of a stall. 6. Failure to achieve a stall. 7. Improper torque correction. 8. Poor stall recognition and delayed recovery. 9. Excessive altitude loss or excessive airspeed during recovery. 10. Secondary stall during recovery.
Introduction: Stalls can be an unnerving and dangerous experience if they are not compensated for correctly. They are especially dangerous when they occur close to the ground. With the exception of landing an airplane, we do not normally stall the airplane. As a safe pilot you must recognize when a stall is about to occur and be able to recover from the stall. You will be required to demonstrate that you know when a stall is about to occur or is occurring and demonstrate that you can recover from the stall. You will have to demonstrate two types of stalls, the landing or power off stall and the take off or power on stall. Today we will practice both stalls. We will also demonstrate that stalls can occur in various aircraft maneuvers including turns.
WARNING: FAILURE TO EXECUTE THE STALL CORRECTLY COULD RESULT IN THE AIRCRAFT ENTERING A SPIN. KEEP THE AIRCRAFT IN COORDINATED FLIGHT AT ALL TIMES.
A. Lesson Requirements:
a. Task: Identify the conditions leading to stalls, recognize when a stall occurs and provide appropriate corrective action.
b. Condition: Given a functional aircraft
c. Standard: IAW the PTS.
2. Power Off Stalls
a. Exhibits knowledge of the elements related to power-off stalls. b. Selects an entry altitude that allows the task to be completed no lower than 1,500 feet (460 meters) AGL. c. Establishes a stabilized descent in the approach or landing configuration, as specified by the examiner. d. Transitions smoothly from the approach or landing attitude to a pitch attitude that will induce a stall. e. Maintains a specified heading, ±10°, in straight flight; maintains a specified angle of bank not to exceed 20°, ±10°; in turning flight, while inducing the stall. f. Recognizes and recovers promptly after the stall occurs by simultaneously reducing the angle of attack, increasing power to maximum allowable, and leveling the wings to return to a straight and level flight attitude with a minimum loss of altitude appropriate for the airplane. g. Retracts the flaps to the recommended setting; retracts the landing gear, if retractable, after a positive rate of climb is established. h. Accelerates to VX or VY speed before the final flap retraction; returns to the altitude, heading, and airspeed specified by the examiner.
3. Power On Stalls
a. Exhibits knowledge of the elements related to power-on stalls. b. Selects an entry altitude that allows the task to be completed no lower than 1,500 feet (460 meters) AGL. c. Establishes the takeoff or departure configuration. Sets power to no less than 65 percent available power. d. Transitions smoothly from the takeoff or departure attitude to the pitch attitude that will induce a stall. e. Maintains a specified heading, ±10°, in straight flight; maintains a specified angle of bank not to exceed 20°, ±10°, in turning flight, while inducing the stall. f. Recognizes and recovers promptly after the stall occurs by simultaneously reducing the angle of attack, increasing power as appropriate, and leveling the wings to return to a straight-and-level flight attitude with a minimum loss of altitude appropriate for the airplane. g. Retracts the flaps to the recommended setting; retracts the landing gear if retractable, after a positive rate of climb is established. h. Accelerates to VX or VY speed before the final flap retraction; returns to the altitude, heading, and airspeed specified by the examiner.
B. ELO1: Identify the causes of a stall
1. What is a stall? An airplane is in a stalled condition when the aircraft can no longer generate enough lift to fly. Stalls may occur either with power applied (referred to as a power on stall) or with power set to idle (power off). Most landings are performed in a stalled condition.
2. Why do stalls occur? Stalls occur because the wings have exceeded the critical angle of attack and the wing no longer produces lift.
3. When can a stall occur? Stalls can occur at any attitude and at any bank of turn. Stall speed will vary depending on weight, center of gravity and aircraft configuration.
4. Does the whole wing stall at the same time? No. Wings are designed so that they stall at the root first. This allows for aileron effectiveness to continue even after the remainder of the wing stalls.
C. ELO 2: Identify the dangers of stall.
1. Loss of altitude. When a stall occurs the airplane can no longer maintain altitude. There is almost always a loss of altitude in a stall and its subsequent recovery, if a stall occurs close to the ground, the aircraft may strike the ground before it can adequately recover.
2. Nose dropping. When a stall occurs, the nose of the airplane normally drops some degree. This coupled with the loss of altitude; the airplane may strike the ground nose first. The will probably cause a collapse of the nose landing gear and propeller strike.
3. Spin. A spin occurs when one wing of the airplane is stalled more than the other. This causes the airplane to roll toward the side of the “more stalled” wing. If this occurs at sufficient altitude a recovery is normally possible. (Recovery can take 2000 feet or more). A spin CANNOT occur if the airplane is properly coordinated.
D. ELO 3: Identify when a stall is imminent.
1. Visual Cues: This is useful when the plane is in an unusual attitude, but since stalls can occur at any attitude, this should not be the primary sense.
2. Aural Cues: There is a different sound that is produced as the stall approaches. You can hear a difference in the engine sound as the RPM of the engine changes on fixed pitch aircraft.
3. Feeling Cues: The airplane becomes sluggish as the controls become less effective.
4. Buffeting of the aircraft. As the stall approaches the airplane will shake a little.
5. Stall warning indicator. About 5 knots above the stall speed, the stall-warning indicator will activate. This does not mean that a stall is occurring, but only that the aircraft is close to stalling.
6. Student Check:
a. What is VSo on this aircraft? ________ b. What is Vs1 on this aircraft? ________
E. ELO 4: Identify when a stall has occurred.
1. The most common indicator that a stall has occurred will be a drop in the attitude of the airplane.
F. ELO 5: Identify common errors in power-off and power-on stalls.
1. Power-Off Stalls.
a. Failure to establish the specified landing gear and flap configuration prior to entry. b. Improper pitch, heading and bank control during straight ahead stalls. c. Improper pitch and bank during turning stalls. d. Rough or uncoordinated control technique. e. Failure to recognize the first indications of a stall. f. Failure to achieve a stall. g. Improper torque correction. h. Poor stall recognition and delayed recovery. i. Excessive altitude loss or excessive airspeed during recovery. j. Secondary stall during recovery.
2. Power-On Stalls.
a. Failure to establish the specified landing gear and flap configuration prior to entry. b. Improper pitch, heading and bank control during straight ahead stalls. c. Improper pitch and bank during turning stalls. d. Rough or uncoordinated control technique. e. Failure to recognize the first indications of a stall. f. Failure to achieve a stall. g. Improper torque correction. h. Poor stall recognition and delayed recovery. i. Excessive altitude loss or excessive airspeed during recovery. j. Secondary stall during recovery.
G. ELO 6: Put the aircraft in a stalled condition and apply appropriate corrective action. Both Power Off (Landing) and Power On (takeoff) stalls.
1. In flight, I will demonstrate each type of stall and its recovery for you. You will then be required to perform the maneuver yourself.
2. Power Off Stalls:
a. This stall replicates the type of stall you are most likely to encounter during an approach to landing.
b. Procedure
i. Clearing turn
ii. Configure the plane for a normal landing. Gear down (as required), high rpm on the prop, carb heat on, fuel pump on, and full flaps.
iii. Slow the plane down to approach speed.
iv. Slowly reduce power to idle.
v. Begin to pitch up until the stall occurs.
vi. KEEP THE PLANE COORDINATED WITH THE RUDDER. DO NOT USE SUDDEN MOVEMENTS.
vii. To do this in a turn, KEEP THE TURN COORDINATED.
c. Recovery
i. Once the stall occurs, relieve backpressure.
ii. Apply full power.
iii. At PROC retract gear and one notch of flaps.
iv. Retract flaps completely once you reach Vy.
3. Power On Stalls
a. This stall most often occurs when a pilot is executing a go around. The plan is configured for take off. We will do this maneuver both with the flaps (and gear) extended and with them retracted.
b. Procedure:
i. Clearing turn. (If one was not completed already)
ii. Put the airplane in departure configuration as specified by examiner or instructor. (Gear up or gear down, if unsure ask).
iii. Boost pump on. (if equipped)
iv. Slow the plane down to lift-off speed. Reduce power, pitch to maintain altitude.
v. Apply full power, does not necessarily have to be full power. The examiner may tell you or the POH may give a specific limitation.
vi. Apply backpressure on the elevator. Continue applying backpressure until the airplane stalls.
vii. KEEP THE PLANE COORDINATED WITH THE RUDDER. DO NOT USE SUDDEN MOVEMENTS.
viii. To do this in a turn, KEEP THE TURN COORDINATED.
c. Recovery
i. Once the stall occurs, relieve backpressure.
ii. Apply full power.
iii. At PROC retract gear and one notch of flaps. (if extended)
iv. Retract flaps completely once you reach Vy.
4. Student Check:
a. Describe the procedures for entering a power off stall and how to recover from it.
b. Describe the procedures for entering a power on stall and how to recover from it.
H. ELO 7: Identify the causes of a spin and how to recover from a spin.
1. In order to spin, a plane MUST be stalled.
2. A spin is caused by one wing being stalled more than the other wing.
3. What causes a spin to occur? The plane is uncoordinated when it enters a stall.
4. How do you recover from a spin? PARE.
5. Reduce power immediately to idle
6. Neutralize any bank
7. Apply opposite rudder to the direction of the spin. Release this rudder pressure when the rotation stops.
8. Apply forward pressure on the yoke to break the stall.
9. When the plane returns to level flight, apply power.
10. Student Check: Describe the procedures for recovering from a spin.
I. Other stall types. These will not be practiced, but you should be aware of the potential for stalling in these situations:
1. Cross controlled stalls: This type stall occurs with the controls "crossed" - that is, aileron pressure applied in one direction and rudder pressure in the opposite direction.
2. Accelerated stalls: 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 flight path. Stalls entered from such flight situations are called "accelerated maneuver stalls," a term which has no reference to the airspeeds involved.
3. Elevator trim stalls: This occurs when full power is applied and positive control of the aircraft is not maintained.
4. Secondary stalls: This stall is called a secondary stall since it may occur after a recovery from a preceding primary stall. It is caused by attempting to hasten the completion of a stall recovery before the airplane has regained sufficient flying speed.