ELEVATOR TRIM STALLS

Elevator Trim Stalls Lesson by wifiCFI

Objective

Exhibits instructional knowledge of the elements of elevator trim stalls, in selected landing gear and flap configurations by describing: 

Aerodynamics of elevator trims stalls. 

Hazards of inadequate control pressures to compensate for thrust, torque, and up-elevator trim during go-around and other related maneuvers. 

Entry procedure and minimum entry altitude. 

Recognition of elevator trims stalls. 

Importance of recovering from an elevator trim stall immediately upon recognition. 

Exhibits instructional knowledge of common errors related to elevator trim stalls, in selected landing gear and flap configurations by describing: 

Failure to present simulated student instruction that adequately emphasizes the hazards of poor correction for torque and up-elevator trim during go-around and other maneuvers. 

Failure to establish selected configuration prior to entry. 

Improper or inadequate demonstration of the recognition of and the recovery from an elevator trim stall.

Demonstrates and simultaneously explains elevator trim stalls, in selected landing gear and flap configurations, from an instructional standpoint. 

Analyzes and corrects simulated common errors related to elevator trim stalls in selected landing gear and flap configurations.

Elevator Trim Stalls (AFH C4)

The elevator trim stall demonstration shows what can happen when the pilot applies full power for a go-around without maintaining positive control of the airplane. 

This is a demonstration-only maneuver.

This situation may occur during a go-around procedure from a normal landing approach or a simulated, forced-landing approach, or immediately after a takeoff, with the trim set for a normal landing approach glide at idle power. 

The objective of the demonstration is to show the importance of making smooth power applications, overcoming strong trim forces, maintaining positive control of the airplane to hold safe flight attitudes, and using proper and timely trim techniques.

It is imperative to avoid the occurrence of an elevator trim stall during an actual go-around from an approach to landing.

Flying the Maneuver

At a safe altitude and after ensuring that the area is clear of other air traffic, the pilot should slowly retard the throttle and extend the landing gear (if the airplane is equipped with retractable gear). 

The next step is to extend the flaps to the one-half or full position, close the throttle, and maintain altitude until the airspeed approaches the normal glide speed. 

When the normal glide is established, the pilot should trim the airplane nose-up for the normal landing approach glide. 

During this simulated final approach glide, the throttle is then advanced smoothly to maximum allowable power, just as it would be adjusted to perform a go-around. 

The combined effects of increased propwash over the tail and elevator trim tend to make the nose rise sharply and turn to the left. 

With the throttle fully advanced, the pitch attitude increases above the normal climbing attitude. 

When it is apparent the airplane is approaching a stall, the pilot must apply sufficient forward elevator pressure to reduce the AOA and eliminate the stall warning before returning the airplane to the normal climbing attitude. 

The pilot will need to adjust trim to relieve the heavy control pressures and then complete the normal go around procedures and return to the desired flightpath.

Common Errors

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