Steep Turn Procedure

 

 Objective:

To develop smoothness, coordination, orientation, division of attention, and control techniques while executing high performance turns.

Element:

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

2.     Overbanking tendency 

3.     Torque effect in right and left turns (differences between)

4.     Selection of a suitable altitude 

5.     Orientation, division of attention, and planning 

6.     Appropriate power setting and airspeed prior to entry 

7.     Entry and rollout technique 

8.     Coordination of flight controls 

9.     Differential wing drag 

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

The Completion Standard:

1. Exhibits knowledge of the elements related to steep turns

2. Selects an altitude that will allow the task to be performed no lower than 1,500 feet AGL

3. Establishes Va.

4. Rolls into a coordinated 360° turn; maintains a 45° bank, ±5°; and rolls out on the entry heading, ±10°. 

5. Performs the task in the opposite direction, as specified by the instructor

6. Divides attention between airplane control and orientation

7. Maintains the entry altitude, ±100 feet, and airspeed, ±10 knots

Common Errors:

 1.     Failure to adequately clear the area.

2.     Excessive pitch change during entry or recovery.

3.     Attempt to start recovery prematurely.

4.     Failure to stop the turn on a precise heading.

5.     Excessive rudder during recovery, resulting in skidding.

6.     Inadequate power management.

7.     Inadequate airspeed control.

8.     Poor coordination.

9.     Gaining altitude in right turns and / or losing altitude in left turns.

10.  Failure to maintain constant back angle.

11.  Disorientation.

12.  Attempting to perform the maneuver by instrument reference rather than visual reference.

13. Failure to scan for other traffic during the maneuver

SETTING UP FOR MANEUVER

1. Set power to obtain a speed below maneuvering speed (Va)

2. Clearing turns to check for other aircraft.

3. Trim.

4. Select a heading or reference point for rollout

STARTING MANEUVER

1. From straight-and level flight, coordinate aileron and rudder  to roll into a (private PTS) 45° turn.

2. Exert back pressure on the control column to maintain altitude.

3. Increase throttle to maintain airspeed.

4. Due to torque effect, more rudder is required to roll into a right turn

MAINTAINING MANEUVER

1. Select a reference point on the horizon to maintain altitude and bank angle

2. Maintain bank angle with aileron

3. Control P-factor and torque with rudder

4. Maintain altitude with elevator. (reference altimeter)

5. Trim to relieve control pressures

6. Add power as required to maintain airspeed

7. Anticipate the rollout heading or reference point.  Lead the rollout by ½ of the bank angle

8. Roll out of bank with aileron stop adverse yaw with rudder

9. During the rollout release elevator back pressure

10. Reduce power to maintain airspeed

11. Repeat the turn in opposite direction.

Steep Turn Narrative

INTRODUCTION

     The objective of the maneuver is to develop the smoothness, coordination, orientation, division of attention, and control techniques necessary for the execution of maximum performance turns when the airplane is near its performance limits. Smoothness of control use, coordination, and accuracy of execution are the important features of this maneuver.

DESCRIPTION

      The steep turn maneuver consists of a turn in either direction, using a bank angle between 45 to 60°. This will cause an overbanking tendency during which maximum turning performance is attained and relatively high load factors are imposed. Because of the high load factors imposed, these turns should be performed at an airspeed that does not exceed the airplane’s design maneuvering speed (VA). The principles of an ordinary steep turn apply, but as a practice maneuver the steep turns should be continued until 360° or 720° of turn have been completed. An airplane’s maximum turning performance is its fastest rate of turn and its shortest radius of turn, which change with both airspeed and angle of bank. Each airplane’s turning performance is limited by the amount of power its engine is developing, its limit load factor (structural strength), and its aerodynamic characteristics.

      The limiting load factor determines the maximum bank, which can be maintained without stalling or exceeding the airplane’s structural limitations.  In most small planes, the maximum bank has been found to be approximately 50° to 60°.  The pilot should realize the tremendous additional load that is imposed on an airplane as the bank is increased beyond 45°. During a coordinated turn with a 70° bank, a load factor of approximately 3 Gs is placed on the airplane’s structure. Most general aviation type airplanes are stressed for approximately 3.8 Gs.

      Regardless of the airspeed or the type of airplanes involved, a given angle of bank in a turn, during which altitude is maintained, will always produce the same load factor.  Pilots must be aware that an additional load factor increases the stalling speed at a significant rate—stalling speed increases with the square root of the load factor.  For example, a light plane that stalls at 60 knots in level flight will stall at nearly 85 knots in a 60° bank.   The pilot’s understanding and observance of this fact is an indispensable safety precaution for the performance of all maneuvers requiring turns.  Before starting the steep turn, the pilot should ensure that the area is clear of other air traffic since the rate of turn will be quite rapid.

BEGINNING

1.   After establishing the manufacturer’s recommended entry speed or the design maneuvering speed, the airplane should be smoothly rolled into a selected bank angle between 45 to 60°.

2.  As the turn is being established, back-elevator pressure should be smoothly increased to increase the angle of attack.  This provides the additional wing lift required to compensate for the increasing load factor.

3.  After the selected bank angle has been reached, there will be considerable force required on the elevator control to hold the airplane in level flight and to maintain altitude.

NOTE: Because of this increase in the force applied to the elevators, the load factor increases rapidly as the bank is increased.

4.  Additional back-elevator pressure increases the angle of attack, which results in an increase in drag.

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

6.  Eventually, as the bank approaches the airplane’s maximum angle, the maximum performance or structural limit is being reached. If this limit is exceeded, the airplane will be subjected to excessive structural loads, and will lose altitude, or stall.

7.  The limit load factor must not be exceeded, to prevent structural damage.

8.  During the turn, do not stare at any one object.

NOTE: To maintain altitude, as well as orientation, requires an awareness of the relative position of the nose, the horizon, the wings, and the amount of bank.

9. Referencing the aircraft’s turn by watching only the nose will cause difficulty in holding altitude constant; on the other hand, watching the nose, the horizon, and the wings can usually result in holding altitude within a few feet.

10. If the altitude begins to increase, or decrease, relaxing or increasing the back-elevator pressure will be required as appropriate. This may also require a power adjustment to maintain the selected airspeed.

11.  A small increase or decrease of 1 to 3° of bank angle may be used to control small altitude deviations.

12.  All bank angle changes should be done with coordinated use of aileron and rudder.

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

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

Lesson Plan Notes:

Introduction Steep turns are like normal turns, but everything is amplified - this allows you to really understand the anatomy of a turning aircraft, and to perform it proficiently. Motivation q Although steep turns are not performed in every day flight, the aid the student in analyzing the forces acting on an aircraft, and in developing fine control touch, coordination and division of attention.  DEVELOPMENT q Explain the Design Maneuvering Speed VA. q Explain the forces acting on an aircraft during a turn, including stability and overbanking tendencies q Explain relationship of bank angle and load factor - Increase in AoA required to compensate for load factor. q Additional Power is needed since increased AoA develops additional drag q Explain how increase in load factor increases stall speed q Explain importance of coordinated use of aileron and rudder  INFLIGHT q Altitude > 1500’, clear the area, choose a visual reference point, and note the heading and altitude. q Establish Manufacturer’s recommended entry speed or VA, and perform a well coordinated roll into a 45° (or 50° for commercial) bank while adding power, and increasing back pressure. q Explain the sight picture, and how to detect changes in aircraft bank and pitch based on the sight picture q Explain how to anticipate rollout (generally ½ bank angle) q Demonstrate and emphasize smoothness, coordination, orientation & division of attention  POSTFLIGHT q Conduct a critique and review procedures and techniques.  TEACHING NOTES q Load factor: ratio of lift force produced by the wings to the weight of aircraft. During a bank the lift force generated by the wings must increase greatly, so the VCOL can counteract the weight (TT2-69) q Increasing back pressure increase the AOA, and due to the increased load factor more power must be added to hold airspeed q Wing loading is load supported by the wings divided by their area q Maneuver should be performed <= VA due to load factors. Limiting load factor determines max bank q Stall speed increases with the square root of load factor - Accelerated stall (>1g maneuvers) q Review aerodynamics q Shallow turns (less than 20° degrees) - inherent stability of the airplane levels the wings unless control force is used to maintain the bank. q Medium turns (20° to 45°) - airplane tends to hold a constant bank without control force on the ailerons. q Steep turns (>= 45°) - overbanking tendency of the airplane overcomes stability, and the bank tends to increase unless pressure is applied to the aileron controls to prevent it (outside wing traveling further in same amount of time . faster)