Cross Controlled Stalls Lesson by wifiCFI
Exhibits instructional knowledge of the elements of cross controlled stalls, with the landing gear extended by describing:
Aerodynamics of cross-controlled stalls.
Effects of crossed controls in gliding or reduced airspeed descending turns.
Flight situations where unintentional cross-controlled stalls may occur.
Entry procedure and minimum entry altitude.
Recognition of cross-controlled stalls.
Recovery procedure and minimum recovery altitude.
Exhibits instructional knowledge of common errors related to cross-controlled stalls, with the landing gear extended by describing:
Failure to establish selected configuration prior to entry.
Failure to establish a cross-controlled turn and stall condition that will adequately demonstrate the hazards of a cross-controlled stall.
Improper or inadequate demonstration of the recognition and recovery from a cross-controlled stall.
Failure to present simulated student instruction that emphasizes the hazards of a cross-controlled condition in a gliding or reduced airspeed condition.
Demonstrates and simultaneously explains a cross controlled stall, with the landing gear extended, from an instructional standpoint.
Analyzes and corrects simulated common errors related to a cross-controlled stall with the landing gear extended.
Cross Controlled Stalls (AFH C4)
The objective of the cross-control stall demonstration is to show the effects of uncoordinated flight on stall behavior and to emphasize the importance of maintaining coordinated flight while making turns.
This is a demonstration-only maneuver.
The aerodynamic effects of the uncoordinated, cross-control stall can surprise the unwary pilot because it can occur with very little warning and can be deadly if it occurs close to the ground.
The nose may pitch down, the bank angle may suddenly change, and the airplane may continue to roll to an inverted position, which is usually the beginning of a spin.
It is therefore essential for the pilot to follow the stall recovery procedure by reducing the AOA until the stall warning has been eliminated, then roll wings level using ailerons, and coordinate with rudder inputs before the airplane enters a spiral or spin.
A cross-control stall occurs when the critical AOA is exceeded with aileron pressure applied in one direction and rudder pressure in the opposite direction, causing uncoordinated flight.
A skidding cross-control stall is most likely to occur in the traffic pattern during a poorly planned and executed base-to-final approach turn in which the airplane overshoots the runway centerline and the pilot attempts to correct back to centerline by increasing the bank angle, increasing back elevator pressure, and applying rudder in the direction of the turn (i.e., inside or bottom rudder pressure) to bring the nose around further to align it with the runway.
The difference in lift between the inside and outside wing will increase, resulting in an unwanted increase in bank angle.
At the same time, the nose of the airplane slices downward through the horizon.
The natural reaction to this may be for the pilot to pull back on the elevator control, increasing the AOA toward critical.
Should a stall be encountered with these inputs, the airplane may rapidly enter a spin.
The safest action for an “overshoot” is to perform a go-around.
Flying the Maneuver
Before performing this stall, establish a safe altitude for entry and recovery in the event of a spin, and clear the area of other traffic while slowly retarding the throttle.
The next step is to lower the landing gear (if equipped with retractable gear), close the throttle, and maintain altitude until the airspeed approaches the normal glide speed.
To avoid the possibility of exceeding the airplane’s limitations, do not extend the flaps.
While the gliding attitude and airspeed are being established, the airplane should be retrimmed.
Once the glide is stabilized, the airplane should be rolled into a medium-banked turn to simulate a final approach turn that overshoots the centerline of the runway.
During the turn, smoothly apply excessive rudder pressure in the direction of the turn but hold the bank constant by applying opposite aileron pressure.
At the same time, increase back elevator pressure to keep the nose from lowering.
All of these control pressures should be increased until the airplane stalls.
When the stall occurs, recover by applying nose-down elevator pressure to reduce the AOA until the stall warning has been eliminated, remove the excessive rudder input and level the wings, and apply power as needed to return to the desired flightpath.
Failure to adequately clear the area
Over-reliance on the airspeed indicator and slip-skid indicator while excluding other cues
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
Certified Flight Instructor Practical Test Standards (PTS)
Airplane Flying Handbook (AFH) Chapter 4