POWER ON STALLS

Power On Stalls Lesson by wifiCFI


Objective

To determine that the applicant exhibits satisfactory knowledge, risk management, and skills associated with power on stalls.

Knowledge

The applicant demonstrates understanding of: 

Aerodynamics associated with stalls in various aircraft configurations, to include the relationship between angle of attack, airspeed, load factor, power setting, aircraft weight and center of gravity, aircraft attitude, and yaw effects. 

Stall characteristics and impending stall and full stall indications.

Factors and situations that can lead to a power-on stall and actions that can be taken to prevent it. 

Fundamentals of stall recovery.

Risk Management

The applicant demonstrates the ability to identify, assess and mitigate risks, encompassing: 

Factors and situations that could lead to inadvertent power-off stall, spin, and loss of control.  

Range and limitations of stall warning indicators. 

Failure to recognize and recover at the stall warning during normal operations. 

Improper stall recovery procedure. 

Secondary stalls, accelerated stalls, and cross-control stalls. 

Effect of environmental elements on aircraft performance related to power-off stalls. 

Collision hazards, to include aircraft, terrain, obstacles, and wires. 

Distractions, loss of situational awareness, and/or improper task management.

Stalls (AFH C4)

A stall is an aerodynamic condition which occurs when smooth airflow over the airplane’s wings is disrupted, resulting in loss of lift. 

Specifically, a stall occurs when the AOA, the angle between the chord line of the wing and the relative wind, exceeds the wing’s critical AOA. 

It is possible to exceed the critical AOA at any airspeed, at any attitude, and at any power setting. 

Impending Stall

An impending stall occurs when the AOA causes a stall warning, but has not yet reached the critical AOA. 

Indications of an impending stall can include buffeting, stick shaker, or aural warning. 

Full Stall

A full stall occurs when the critical AOA is exceeded. 

Indications of a full stall are typically that an uncommanded nose-down pitch cannot be readily arrested, and this may be accompanied by an uncommanded rolling motion. 

Stall Recovery

Depending on the complexity of the airplane, stall recovery could consist of as many as six steps. 

Even so, the pilot should remember the most important action to an impending stall or a full stall is to reduce the AOA.

However, a pilot should always follow the aircraft-specific manufacturer’s recommended procedures if published and current.

Disconnect the wing leveler or autopilot (if equipped). 

Pitch nose-down control. 

Trim nose-down pitch. 

Roll wings level.

Add thrust/power.

Retract speedbrakes/spoilers (if equipped).

Return to the desired flightpath.

Power On Stalls (AFH C4)

Power-on stall recoveries are practiced from straight climbs and climbing turns (15° to 20° bank) to help the pilot recognize the potential for an accidental stall during takeoff, go around, climb, or when trying to clear an obstacle. 

Airplanes equipped with flaps 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 gear retracted) to ensure practice with all possible takeoff and climb configurations. 

Power for practicing the takeoff stall recovery should be maximum power, although for some airplanes it may be reduced to a setting that will prevent an excessively high pitch attitude.

Performing the Maneuver

To set up the entry for power-on stalls, establish the airplane in the takeoff or climb configuration.

Slow the airplane to normal lift-off speed while continuing to clear the area of other traffic. 

Upon reaching the desired speed, set takeoff power or the recommended climb power for the power-on stall (often referred to as a 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 establishing the climb attitude, smoothly raise the nose to increase the AOA, and hold that attitude until the full stall occurs.

In most airplanes, as the airspeed decreases the pilot must move the elevator control progressively further back while simultaneously adding right rudder and maintaining the climb attitude until reaching the full stall.

Private Pilot and Commercial Pilot ACS Standards

Clear the area. 

Select an entry altitude that will allow the task to be completed no lower than 1,500 feet AGL (ASEL) or 3,000 feet AGL (AMEL). 

Configure the airplane in the approach or landing configuration, as specified by the evaluator, and maintain coordinated flight throughout the maneuver. 

Establish a stabilized descent. 

Transition smoothly from the approach or landing attitude to a pitch attitude that will induce a stall. 

Maintain a specified heading, ±10 if in straight flight; maintain a specified angle of bank not to exceed 20°, ±10°, if in turning flight, while inducing the stall. 

Acknowledge cues of the impending stall and then recover promptly after a full stall has occurred. 

Execute a stall recovery in accordance with procedures set forth in the POH/AFM.

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

Accelerate to VX or VY speed before the final flap retraction; return to the altitude, heading, and airspeed specified by the evaluator. 

Common Errors

Failure to adequately clear the area 

Over-reliance on the airspeed indicator and slip-skid indicator while excluding other cues 

Inadvertent accelerated stall by pulling too fast on the controls during a power-off or power on stall entry 

Inability to recognize an impending stall condition 

Failure to take timely action to prevent a full stall during the conduct of impending stalls 

Failure to maintain a constant bank angle during turning stalls 

Failure to maintain proper coordination with the rudder throughout the stall and recovery 

Recovering before reaching the critical AOA when practicing the full stall maneuver 

Not disconnecting the wing leveler or autopilot, if equipped, prior to reducing AOA 

Recovery is attempted without recognizing the importance of pitch control and AOA 

Not maintaining a nose down control input until the stall warning is eliminated 

Pilot attempts to level the wings before reducing AOA 

Pilot attempts to recover with power before reducing AOA 

Failure to roll wings level after AOA reduction and stall warning is eliminated 

Inadvertent secondary stall during recovery 

Excessive forward-elevator pressure during recovery resulting in low or negative G load 

Excessive airspeed buildup during recovery 

Losing situational awareness and failing to return to desired flightpath or follow ATC instructions after recovery.

FAA Sources Used for This Lesson

Private Pilot Airmen Certification Standards

Commercial Pilot Airmen Certification Standards

Airplane Flying Handbook (AFH) Chapter 4

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