Power on Stall Procedure

 Objective:

To develop the pilot's ability to recognize an approaching stall by sound, sight, and feel; familiarize the pilot with the conditions that produce power-on stalls; and to develop the habit of taking prompt preventative or corrective action to recover from a stall.

Elements:

1.     Aerodynamics of power-on stalls.

2.     Relationship of various factors such as landing gear and flap configuration, weight, center of gravity, load factor, and bank angle to stall speed.

3.     Flight situations where unintentional power-on stalls may occur.

4.     Recognition of the first indications of power-on stalls.

5.     Performance of power-on stalls in climbing flight (straight or turning).

6.     Entry technique and minimum entry altitude.

7.     Coordination of flight controls.

8.   Recovery technique and minimum recovery altitude.

The Completion Standard:

1.  Exhibits knowledge of the elements related to power-on stalls

2.  Selects an entry altitude that allows the task to be completed no lower than 1,500 feet AGL

3.  Establishes the takeoff/departure configuration. Sets power to no less than 65 percent available power

4.  Transitions smoothly from the takeoff or departure attitude to the pitch attitude that will induce a stall

5.  Maintains hdg, ±10°, in straight flt ;bank not to exceed 20°, ±10°, in turning flt, while inducing the stall

6.  Recognizes/recovers promptly after the stall occurs by simultaneously reducing the AOA, 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

7.  Retracts the flaps to the recommended setting; retracts the landing gear if retractable, after a positive rate of climb is established

8.  Accelerates to VX or VY speed before the final flap retraction; returns to the altitude, heading, and airspeed specified by the examiner

Common Errors:

1.     Failure to adequately clear the area.

2.     Inability to recognize an approaching stall condition through feel for the airplane.

3.     Premature recovery.

4.     Over-reliance on the airspeed indicator while excluding other cues.

5.     Inadequate scanning resulting in an unintentional wing-low condition during entry.

6.     Excessive back-elevator pressure resulting an exaggerated nose-up attitude during entry.

7.     Inadequate rudder control.

8.     Inadvertent secondary stall during recovery.

9.     Failure to maintain a constant bank angle during turning stalls.

10.  Excessive forward-elevator pressure during recovery resulting in negative load on the winds.

11.  Excessive airspeed buildup during recovery.

12. Failure to take timely action to prevent a full stall during the conduct of imminent stalls

Power-On Stall Technique (Clean Configuration):

DESCRIPTION: Select an altitude to allow recovery above 1500’ AGL. Perform Pre-Maneuver Checklist. Perform clearing turns. Apply carburetor heat, as appropriate. Reduce power to 1200 RPM ( or 12” MP). Smoothly increase pitch to maintain altitude as airspeed decreases. As airspeed approaches Vlof, smoothly apply power to full, shutting off carburetor heat, as appropriate, while increasing pitch. Note: Some aircraft may require a reduced  power setting to avoid excessively nose high pitch attitudes. Initiate recovery when: ·       Imminent stall: the first buffet or rapid decay of control effectiveness is experienced. ·       Full stall: A sudden loss of control effectiveness occurs, excessive sink rate, or sudden nose pitch down with full up elevator is experienced. Recover by simultaneously verifying full power, decreasing the angle of attack, and leveling the wings. Establish a pitch attitude to minimize altitude loss (approximately Vx attitude) and establish a positive rate of climb. ·       When a positive rate of climb has been obtained and the aircraft is clear of obstacles (simulated), establish Vy attitude. Resume normal cruise, or as specified.

Power-On Stall Narrative (Clean Configuration):

FULL STALLS POWER-ON ·       Power-on stall recoveries are practiced from straight climbs, and climbing turns with 15 to 20° banks, to simulate an accidental stall occurring during takeoffs and climbs. ·       Airplanes equipped with flaps and/or retractable landing gear should normally be in the takeoff configuration; however, power-on stalls should also be practiced with the airplane in a clean configuration (flaps and/or gear retracted) as in departure and normal climbs. ·       After establishing the takeoff or climb configuration, the airplane should be slowed to the normal lift-off speed while clearing the area for other air traffic. ·       When the desired speed is attained, the power should be set at takeoff power for the takeoff stall or the recommended climb power for the departure stall while establishing a climb attitude. ·       The purpose of reducing the airspeed to lift-off airspeed before the throttle is advanced to the recommended setting is to avoid an excessively steep nose-up attitude for a long period before the airplane stalls. ·       After the climb attitude is established, the nose is then brought smoothly upward to an attitude obviously impossible for the airplane to maintain and is held at that attitude until the full stall occurs. ·       In most airplanes, after attaining the stalling attitude, the elevator control must be moved progressively further back as the airspeed decreases until, at the full stall, it will have reached its limit and cannot be moved back any farther. ·       Recovery from the stall should be accomplished by immediately reducing the angle of attack by positively releasing back-elevator pressure and, in the case of a departure stall, smoothly advancing the throttle to maximum allowable power. ·       In this case, since the throttle is already at the climb power setting, the addition of power will be relatively slight. ·       The nose should be lowered as necessary to regain flying speed with the minimum loss of altitude and then raised to climb attitude. ·       Then, the airplane should be returned to the normal straight-and-level flight attitude, and when in normal level flight, the throttle should be returned to cruise power setting. ·       The pilot must recognize instantly when the stall has occurred and take prompt action to prevent a prolonged stalled condition. SECONDARY STALL ·       This stall is called a secondary stall since it may occur after a recovery from a preceding stall. ·       It is caused by attempting to hasten the completion of a stall recovery before the airplane has regained sufficient flying speed. ·       When this stall occurs, the back-elevator pressure should again be released just as in a normal stall recovery. When sufficient airspeed has been regained, the airplane can then be returned to straight-and-level flight. ·       This stall usually occurs when the pilot uses abrupt control input to return to straight-and-level flight after ·       a stall or spin recovery. ·       It also occurs when the pilot fails to reduce the angle of attack sufficiently during stall recovery by not lowering pitch attitude sufficiently, or by attempting to break the stall by using power only. ACCELERATED STALLS ·       Though the stalls just discussed normally occur at a specific airspeed, the pilot must thoroughly understand ·       that 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 airspeeds involved. ·       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 be allowed. ·       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 back elevator pressure must be released, power added, and the airplane returned to straight-and-level flight with coordinated control pressure. ·       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.

Power On Stall