Lesson Overview

The student should develop knowledge of the elements related to steep turns (load factors, torque, adverse yaw, and the overbanking tendency). The student should have the ability to perform a steep turn as required in the ACS/PTS.

References : Airplane Flying Handbook (FAA-H-8083-3C, page(s) 9-1)

Key Elements

  1. Overbanking Tendency

  2. Coordination

  3. Increased back pressure and thrust are required to maintain altitude

  4. Maintain altitude with elevators and bank angle
Elements

  1. The Science Behind It

  2. Performing the Steep Turn
Schedule

  1. Discuss Objectives

  2. Review material

  3. Development

  4. Conclusion
Equipment

  1. White board and markers

  2. References
IP Actions

  1. Discuss lesson objectives

  2. Present Lecture

  3. Ask and Answer Questions

  4. Assign homework
SP Actions

  1. Participate in discussion

  2. Take notes

  3. Ask and respond to questions
Completion Standards

The student understands the characteristics behind the factors involved in the steep turn and can properly perform them in both directions maintaining altitude and airspeed.

Instructor Notes

Attention

Steep turns - the first really fun maneuver! Steep banks, you feel some G’s and you’re staring at the ground out the side window!
Overview

Review Objectives and Elements/Key ideas
What

The steep turn maneuver consists of a constant altitude turn in either direction, using a bank angle between 45° to 60° (45° - Private, or 50° - Commercial). This will cause an overbanking tendency during which maximum turning performance is attained and relatively high load factors are imposed.
Why

Steep turns develop smoothness, coordination, orientation, division of attention, and control techniques necessary for the execution of maximum performance turns. The pilot also understands the effects of the over banking tendency and how to counteract it.

Lesson Details

An airplane’s maximum turning performance is its fastest rate of turn and shortest radius of turn. This changes with both airspeed and angle of bank. An airplane’s turning performance is also limited by the amount of power the engine is developing, the aircraft’s limit load factor, and other aerodynamic characteristics. One critical limit to the maximum bank is the aircraft structural maximum load limit, which generally limits the bank to approximately 50° to 60°, in small aircraft.

An aircraft turns by banking. When banked the total lift is divided into horizontal and vertical components. It is the horizontal component that pulls the aircraft through the turn.

Load Factors

As the bank angle increases past 45° the load factor increases. At a 60° bank a load factor of 2Gs is placed on the structure, and at a 70° bank the load factor goes to 3Gs. Most general aviation aircraft are tested to about 3.8Gs.

Regardless of the airspeed, a given bank angle during which altitude is maintained will always produce the same load factor. Increases in load factor also increase the stall speed. This increase in stall speed as at the square root of the load factor. Understanding how bank affects load factor is critical for safely performing any maneuvers requiring turns.

Adverse Yaw

In a turn the downward deflected aileron produces more lift, and therefore more drag. This added drag attempts to yaw the aircraft’s nose in the direction of the raised wing. This yawing tendency is counteracted by use of rudder. With lower airspeeds the vertical stabilizer/rudder combination becomes less effective therefore magnifying the control problems associated with adverse yaw.

Torque Effect

The internal engine parts and propeller are revolving in one direction, thus an equal force is trying to rotate the airplane in the opposite direction. This is the result of Newton’s 3rd law, and the force produced by the revolving assembly is known as torque. It acts around the longitudinal axis and wants to make the aircraft roll to the left.

In a left turn, this torque effect there is a tendency for the aircraft to want to develop a skid. With most normal aircraft engines this will require right rudder to counteract, and varying amounts of rudder will be needed under varying situations.

In a right turn this torque effect results in a tendency to develop a slip. This may also result in a need to apply right rudder in a turn. However, adverse yaw acts in opposition to other yawing moments to minimize the slipping tendency.

Over-banking Tendency

Over-banking occurs when the aircraft is banked steeply enough such that it reaches a condition of negative static stability about the longitudinal axis. The term "static stability" refers to the initial response of a system to a disturbance, and can be positive, neutral, or negative. As most aircraft are banked they start in a state of positive static stability, shows neutral stability in a medium bank, and finally shows negative static stability in a steep bank. This negative static stability causes the aircraft to want to continue to bank more, resulting in the over-banking tendency.

This condition is intentional, in that aircraft are designed with limited positive static stability around the longitudinal axis so that they will be easier to turn, but will return to straight-and-level flight from shallow banks. The design factors that affect lateral stability around the longitudinal axis are :

  • Dihedral

  • Sweepback Angles

  • Keel Effect

  • Weight Distribution

Dihedral

This is the angle at which the wings are slanted upward form the root to the tip. This involves a balance of lift created by the wings angle of attack on each side of the airplane’s longitudinal axis. The airplane tends to sideslip or slide downward toward the lowered wing. Since the wings have dihedral the air strikes the low wing at a much greater angle of attack than the high wing. This causes the low wing to generate more lift, thus restoring the aircraft to it’s original attitude.

Sweepback

This is the angle at which the wings are slanted rearward from the root to the tip. Sweepback produces the same effect on stability as dihedral, but the effect is not as pronounced. Sweepback increases dihedral to achieve stability.

Keel Effect

This depends upon the action of the relative wind on the side area of the fuselage. Laterally stable airplanes are constructed so that hte greater portion of the keel area is above and behind the center of gravity. Therefore, when the airplane slips to one side the combination of the airplane’s weight and the pressure of the airflow against the upper portion of the keel area tends to roll the airplane back to wings level flight.

Weight Distribution

If the weight offset to one side of the aircraft or the other, the aircraft will have a tendency to bank in that direction. This can be seen most vividly in aircraft designed to be steered by virtue of "weight shift" on the part of the pilot.

Why Over-Banking Occurs

As the radius of the turn becomes smaller a significant difference develops between the speed of the inside wing versus the outside wing. The wing on the outside of the turn travels a further distance than the inside, thus traveling faster. This higher speed generates more lift, and that differential causes the aircraft to want to increase the bank.

As a shallow bank changes to a medium bank then to a steep bank, the differential between the inside and outside wings increase. In a medium bank the force created exactly balances the force of the inherent lateral stability of the airplane so that at a given speed n aileron pressure is required to maintain the bank. As the radius decreases further when the bank progresses from a medium bank to a steep bank, the lift differential overbalances the lateral stability and counteractive pressure on the ailerons is necessary to keep the bank from steepening the turn.

Performing the Steep Turn

Before Starting

  1. The first step is to run the pre-maneuver checklist.

  2. Select an altitude which is no more than 1,500 feet AGL, and pick an altitude which is easy to read on the altimeter. Selecting 500 foot increments are easiest.

  3. Ensure the area is clear of traffic, particularly since the rate of turn will be rapid.

  4. Establish the manufacturer’s recommended entry speed, or aircraft design maneuvering speed.

  5. Verify that the aircraft is in straight-and-level flight.

Entering the Turn

  1. First note the entry heading

  2. Smoothly roll into the selected bank angle

    1. 45° (Private)

    2. 50° (Commercial)

    3. Apply rudder as necessary to maintain coordination

    4. Establish opposite aileron as necessary to maintain the bank angle through the maneuver

  3. As the turn is established, smoothly introduce back elevator pressure to increase the angle of attack

    1. A good technique is to begin increasing back pressure when passing 30° of bank

    2. The back pressure provides the additional wing lift required to compensate for the increasing load factor as well as the reduced vertical component of lift

    3. Trim the airplane of excess control pressures (optional)

  4. Power must be added to maintain the entry altitude and airspeed

    1. Additional back-elevator pressure increases the angle of attack, which results in an increase in drag, requiring added power

    2. Begin increasing power as required when passing approximately 30° of bank as well

During the Turn

  1. Do not focus or stare at any one object.

    1. To maintain altitude as well as orientation. you must have an awareness of the relative position of the nose, the horizon, the wings, and the amount of bank. Only watching the nose will result in difficulty holding altitude constant. Watching all can result in holding altitude within a few feet.

  2. Make adjustments as needed

    1. Manage increasing/decreasing altitude by relaxing or increasing back pressure as needed. Power should be adjusted to maintain entry airspeed. A small increase or decrease of 1° to 3° can be used to control small altitude deviations.

    2. If the aircraft is descending and the bank angle is excessive a reduction in the bank angle may stop the descent, conversely if ascending and the bank angle is shallow increasing it may stop the climb.

  3. Maintain coordination with proper rudder use.

Rolling out of the Turn

  1. The rollout should be timed such that the wings reach level flight when the airplane is exactly on the heading from which the maneuver was started.

    1. A general rule is to begin the rollout 20° to 25° prior to the entry heading.

  2. While the rollout is being made, back elevator pressure is gradually released and power reduced, as necessary, to maintain altitude and airspeed

Common Errors

  • Improper pitch, bank, and power coordination during entry and rollout

  • Uncoordinated use of flight controls

  • Improper procedure in correcting altitude deviations

  • Loss of orientation

Conclusion

In maintaining a properly coordinated steep turn, the pilot must use opposite aileron to maintain bank. Pitch should be controlled by adjusting elevator back pressure and bank angle. A smaller bank angle will result in more lift while an increased bank angle will reduce the lift. Maintaining coordination is very important and should be watched carefully throughout the maneuver.

ACS Requirements

To determine that the applicant:

  1. Exhibits instructional knowledge of the elements of steep turns by describing:

    1. Relationship of bank angle, load factor, and stalling speed.

    2. Overbanking tendency.

    3. Torque effect in right and left turns.

    4. Selection of a suitable altitude.

    5. Orientation, division of attention, and planning.

    6. Entry and rollout procedure.

    7. Coordination of flight and power controls.

    8. Altitude, bank, and power control during the turn.

    9. Proper recovery to straight-and-level flight.

  2. Exhibits instructional knowledge of common errors related to steep turns by describing:

    1. Improper pitch, bank, and power coordination during entry and rollout.

    2. Uncoordinated use of flight controls.

    3. Improper procedure in correcting altitude deviations.

    4. Loss of orientation.

  3. Demonstrates and simultaneously explains steep turns from an instructional standpoint.

  4. Analyzes and corrects simulated common errors related to steep turns.

Private Pilot ACS Skills Standards

  1. Clear the area.

  2. Establish the manufacturer’s recommended airspeed or, if not stated, a safe airspeed not to exceed VA.

  3. Roll into a coordinated 360° steep turn with approximately a 45° bank.

  4. Perform the Task in the opposite direction, as specified by evaluator.

  5. Maintain the entry altitude ±100 feet, airspeed ±10 knots, bank ±5°, and roll out on the entry heading ±10°.

Commercial Pilot ACS Skills Standards

The same as the Private Pilot, except:

  1. Roll into a coordinated 360° steep turn with approximately a 50° bank.

  2. Perform the Task in the opposite direction.