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Elevator Trim Stalls

Introduction:

  • Stalls do NOT occur without warning
    • While flying along in cruise flight, a stall will not rip the airplane out of the sky and throw it uncontrollably to the ground to a big smoking crater
  • Elevator trim stalls show what can happen when full power is applied for a go-around and positive control of the airplane is not maintained
  • Shows the importance of smooth power applications, overcoming strong trim forces, and maintaining positive control

Stall Avoidance

  • Avoid flying at minimum airspeeds
  • Remain in the normal flight envelope
  • Avoid abrupt maneuvers

WARNING:
All procedures here are GENERALIZED for learning.
Fly the maneuver in accordance with the Pilot Operating Handbook (POH)
and/or current Standard Operating Procedures (SOPs)


C-172S Procedure:

  1. Select an altitude where recovery will occur no lower than 1500' AGL
  2. Commence a clearing turn
  3. Reduce power to 1500 RPM, adjusting pitch to maintain altitude
  4. Below Vfe 10° (110 KIAS), extend the flaps to 10°, adjusting pitch (trimming) to maintain altitude
  5. Below Vfe 30° (85 KIAS), extend the flaps to 30°, adjust pitch (trimming) to maintain altitude
  6. Maintain altitude until reaching 70 KIAS, and then establish a stabilized descent (trimmed) at 65 KIAS to simulate a normal approach to landing (3° down)
  7. Descending no lower than 200' from the entry altitude, apply full throttle, allowing the airplane to roll left and the pitch to increase to the Vx pitch attitude (approx. 7°)
  8. Reduce the angle of attack to regain control effectiveness
  9. Maintain coordinated use of the ailerons and rudder to level the wings
  10. Adjust pitch to the Vy attitude (4-5° up) and retract the flaps to 20° (re-trimming as necessary)
  11. At or above 60 KIAS, retract the flaps to 10°
  12. At or above 65 KIAS, retract the flaps to 0°
  13. Complete cruise checklist

Airplane Flying Handbook, Figure 4-8. Elevator Trim Stall
Figure 1: Airplane Flying Handbook, Elevator Trim Stall
Airplane Flying Handbook, Figure 4-8. Elevator Trim Stall
Figure 1: Airplane Flying Handbook, Elevator Trim Stall

Common Errors:

  • Failure to adequately clear the area
  • Failure to establish the specified landing gear and flap configuration prior to entry
  • Improper pitch, heading, and bank control during straight ahead stalls
  • Use outside and instrument references
  • Right rudder in nose-high power-on condition; release at break
  • Improper pitch and bank control during turning stalls
  • Rough or uncoordinated control technique
  • Failure to recognize the first indications of a stall
  • Failure to achieve a stall
  • Improper torque correction
  • Poor stall recognition and delayed recovery
  • Excessive altitude loss or excessive airspeed during recovery
  • Secondary stall during recovery

Airman Certification Standards:

Conclusion:

  • It is important to note that individual aircraft may have stall characteristics unique to them due to bends/twists which develop in the airframe over time depending on their use

References: