Chapter 9: Performance Maneuvers
Performance maneuvers are intended to enhance a pilot's proficiency in flight control application, maneuver planning, situational awareness, and division of attention.
Mastery of flight is developed as the mechanics of flight become a subconscious application of the flight controls to maneuver the airplane in attitude, orientation, and position.
Instructors should not introduce performance maneuvers until sufficient competency in the fundamentals is consistently demonstrated by the learner.
Initial training for performance maneuvers should always begin with a detailed ground lesson for each maneuver. Training should be segmented into comprehensible building blocks of instruction, which allows the pilot an appropriate level of repetition to develop the required skills.
Steep Turns
Steep turns (kneeboard) consist of single to multiple 360° to 720° turns, in either or both directions, using a bank angle between 45° to 60°.
The objective of the steep turn is to develop a pilot's skill in flight control smoothness and coordination, an awareness of the airplane's orientation to outside references, division of attention between flight control application, and the constant need to scan for hazards.
When performing steep turns, pilots will be exposed to:
- Higher load factors
- The airplane's inherent overbanking tendency
- The loss of vertical component of lift when the wings are steeply banked
- The need for substantial pitch control pressures
- The need for additional power to maintain altitude and airspeed during the turn.
When an airplane is banked, the total lift is divided between the vertical component of lift and the horizontal component of lift. In order to maintain altitude, the pilot must increase the wing's angle of attack (AOA) to ensure that the vertical component of lift is sufficient to maintain altitude.
The load factor is the vector resultant of gravity and centrifugal force.
Total lift must increase substantially to balance the load factor or G-force (G). In a level altitude, 45° banked turn, the resulting load factor is 1.4. In a level altitude, 60° banked turn, the resulting load factor is 2.0, which effectively doubles the airplane's weight. Load factors increase dramatically beyond 60° of bank.
Regardless of airplane or airspeed, the same load factor will always be produced for any given bank angle in a level altitude turn.
Steep turns should be performed at an airspeed that does not exceed the airplanes design maneuvering speed (Va) or the manufacturer's recommended speed.
Maximum turning performance is accomplished when an airplane has both a fast rate of turn and minimum radius of turn. This is accomplished with a combination of airspeed and angle of bank. Each airplane's turning performance is limited by structural and aerodynamic design, as well as available power.
The airplane's limiting load factor determines the maximum bank angle that can be maintained in level flight without exceeding the airplane's structural limitations or stalling. As the load factor increases, stalling speed increases. As the bank angle increases in level flight, the margin between stalling speed and maneuvering speed decreases.
In a bank, stall speed increases at the square root of the load factor.
In a steep turn, the airplane will exhibit overbanking tendency. In shallow banks, the airplane exhibits positive or neutral stability about the longitudinal axis. As the bank angle steepens, the airplane will continue rolling in the direction of the bank unless opposite aileron pressure is applied.
In a steep turn, various left turning tendencies, such as P-factor, require coordination of rudder and aileron.
To begin a steep turn, identify a distant reference (such as a mountain peak or road) to assess when to begin rollout from the turn. Establish design maneuvering speed (Va) or the manufacturer's recommended entry speed. Smoothly roll in to the the desired bank angle. For private pilots, the certification standard is 45° of bank. As the airplane rolls in to the bank, apply elevator back-pressure to increase angle of attack. The higher AOA will create more drag, which will require more power to overcome.
Elevator trim and power can be applied as the maneuver is entered, which will minimize control pressure inputs.
Altitude deviations are common when performing steep turns. A pilot who observes both the nose and the wings relative to the horizon is likely able to maintain altitude within performance standards. If altitude varies, a slight increase or decrease in bank angle can be used to return to the selected altitude. Elevator back-pressure alsop can be used, but it is not as effective.
Prior to reaching the terminating heading, begin the rollout at half the number of degrees of bank. For a 45° banked turn, the pilot can begin the rollout 20-30° before the selected heading. As the maneuver is completed, trim and power must be restored for level flight.
Common errors when performing steep turns include:
- Not clearing the area
- Inadequate pitch control on entry or rollout
- Gaining altitude or losing altitude
- Failure to maintain constant bank angle
- Poor flight control coordination
- Ineffective use of trim
- Ineffective use of power
- Inadequate airspeed control
- Becoming disoriented
- Performing by reference to the flight instrument rather than visual references
- Failure to scan for other traffic during the maneuver
- Attempts to start recovery prematurely
- Failure to stop the turn on designated heading
Steep Spiral
The steep spiral (kneeboard) is a performance maneuver that rapidly dissipates substantial amounts of altitude while remaining over a selected spot. It would be practically used for effective for emergency descents or landings.
Similar to turns around a point, the pilot maintains a constant radius around a surface-based reference point while rapidly descending. At least three 360° turns are completed in the maneuver, terminating no lower than 1,500 AGL.
To perform a steep spiral, the throttle is closed to idle and carburetor heat is applied (if equipped). The aircraft is trimmed for gliding speed.
After glide speed is established, pitch is lowered and the wings are banked no greater than 60°. A constant-radius turn is accomplished by correcting for wind drift, with steeper angles as the airplane turns into a headwind and shallower angles when the airplane has a tailwind.
Operating the engine at idle speed for any prolonged period during the glide may result in excessive engine cooling, spark plug fouling, or carburetor ice. During a steep spiral, the throttle should be periodically advanced to normal cruise power and sustained for a few seconds. A cylinder head temperature gauge can provide the pilot with insight on engine cooling.
Maintaining a constant airspeed throughout a steep spiral is an important skill, since airspeed tends to fluctuate as the bank angle changes.
After three turns, the pilot should roll out toward a definite object or on a specific heading, recovering to a wings-level glide with no change in airspeed, followed by normal cruise flight.
Common errors when performing steep spirals include:
- Not clearing the area
- Inadequate pitch control on entry or rollout
- Gaining altitude
- Not correcting the bank angle to compensate for wind
- Poor flight control coordination
- Ineffective use of trim
- Inadequate airspeed control
- Becoming disoriented
- Performing by reference to the flight instrument rather than visual references
- Not scanning for other traffic during the maneuver
- Not completing the turn on designated heading or reference
Chandelle
A chandelle (kneeboard) is a maximum performance, 180° climbing turn that begins from approximately straight-and-level flight and concludes with the airplane in a wings-level, nose-high attitude just above stall speed.
The goal of a chandelle is to gain the most altitude possible for a given bank angle and power setting.
The standard used to judge the maneuver is the pilot's proficiency at maximizing climb performance for the power and bank selected. The maneuver is not evaluated specifically on the amount of altitude gained.
The first 90° of a chandelle is defined by constant bank and changing pitch. The second 90° of the maneuver is defined by constant pitch and changing bank.
During the first 90°, the pilot will set the bank angle, and then increase power and pitch at a rate so that maximum pitch-up is set at the completion of the first 90°.
If a chandelle is begun with a bank that is too shallow, the pitch angle will increase excessively, and the airplane is likely to stall before it reaches the 180° point.
If a chandelle is begun with a bank that is too steep, the airplane will make a comparatively level turn without enough airspeed loss. This would result in a tendency to raise the nose to reduce speed on rollout.
Starting at the 90° point, the pilot begins a slow and coordinated constant rate rollout so as to have the wings level when the airplane is at the 180° point while maintaining the constant pitch attitude set in the first 90°.
During the first 90°, if the pitch is not correct, airspeed will be either above stall speed, or the airplane may aerodynamically stall prior to the completion of the maneuver.
During the second 90°, if the rate of rollout is too rapid or sluggish, the airplane will either undershoot or exceed the 180° reversal heading turn as the wings come level to the horizon.
The chandelle should be entered from straight-and-level flight or a shallow dive at the airplane's design maneuvering speed (Va), or at an airspeed recommended by the manufacturer.
Once the bank angle is established (generally 30°), a climbing turn should be started with elevator back-pressure applied at a constant rate while simultaneously increasing engine power to the recommended setting.
Since the airspeed is constantly decreasing throughout the chandelle, the effects of left turning tendencies, such as P-factor, becomes more apparent. As airspeed decreases, right-rudder pressure increases. Coordinated flight should be maintained via the inclinometer and slip-skid sensations.
At the 90° point, begin to smoothly roll out of the bank at a constant rate while maintaining the pitch attitude. As the rollout continues, the vertical component of lift increases, permitting a slight decrease in elevator back-pressure to maintain the pitch attitude.
Near the completion of the chandelle, airspeed is slowest, which means right rudder pressure will be substantial for coordinated flight. This is more pronounced in a chandelle to the left, due to propeller forces. In a chandelle to the right, the airplane's left-turning tendencies at high power will dampen the required rudder input for coordinated flight. Either very little left rudder or a reduction in right rudder pressure may be required.
At the completion of 180° of turn, the wings should be leveled to the horizon and the airspeed should be just above stall speed. The airplane's pitch-high attitude should be held momentarily, after which it may be reduced and the airplane returned to straight-and-level cruise flight.
Common errors when performing chandelles include:
- Not clearing the area
- Initial bank is too shallow resulting in a stall
- Initial bank is too steep resulting in failure to gain maximum performance
- Allowing the bank angle to increase after initial establishment
- Not starting the recovery at the 90° point in the turn
- Allowing the pitch attitude to increase as the bank is rolled out during the second 90° of turn
- Leveling the wings prior to the 180° point being reached
- Pitch attitude is low on recovery resulting in airspeed well above stall speed
- Application of flight control pressures is not smooth
- Poor flight control coordination
- Stalling at any point during the maneuver
- Execution of a steep turn instead of a climbing maneuver
- Not scanning for other traffic during the maneuver
- Performing by reference to the flight instrument rather than visual references
Lazy Eight
The lazy eight (kneeboard) develops the proper coordination of the flight controls across a wide range of airspeeds and attitudes. Throughout the maneuver, flight controls are never constant.
S-turns across the road, which is a ground-reference maneuver, are made of opposing 180° turns. The lazy eight adds both a climb and descent to each 180° segment. The first 90° is a climb; the second 90° is a descent.
Prominent reference points must be selected on the natural horizon at 45°, 90°, and 135° from the direction in which the maneuver is started for each 180° turn.
From level flight, a gradual climbing turn is begun in the direction of the 45° reference point, where the maximum pitch-up attitude is reached, as well as a 15° bank angle. As airspeed decreases, the rate of turn increases. Also, as airspeed increases, more rudder input will be required to counter left-turning propeller forces.
If the lazy eight is started with too rapid a roll rate, the 45° point may be reached before the maximum pitch-up attitude is reached.
Beyond the 45° reference point, the pitch-up attitude should begin to decrease slowly toward the horizon until the 90° reference point is reached, where the pitch attitude should be momentarily level with a bank angle of 30°. Airspeed should be 5-10 knots above stall speed.
A the 90° point, where airspeed is lowest, it's possible for opposing aileron and rudder pressures to be required to maintain coordinated flight. This is because of the increased right rudder pressure required to overcome propeller forces at lower airspeeds.
On the descending portion of the turn, the bank should slowly roll out as the pitch attitude decreases The lowest pitch attitude should occur at the 135° reference point.
The wings and nose should be level at the original airspeed just as the 180° point is reached. A climbing turn is then started immediately in the opposite direction to complete the second half of the lazy eight.
If the climbing turn portions of a lazy eight are entered with banks that are too steep, the turn rate will be too fast for the rate of climb. The 180° change of direction will be reached with excessive airspeed.
Common errors when performing lazy eights include:
- Not clearing the area
- Maneuver is not symmetrical across each 180°
- Inadequate or improper selection or use of 45°, 90°, 135° references
- Ineffective planning
- Gain or loss of altitude at each 180° point
- Poor control at the top of each climb segment resulting in the pitch rapidly falling through the horizon
- Airspeed or bank angle standards not met
- Control roughness
- Poor flight control coordination
- Stalling at any point during the maneuver
- Execution of a steep turn instead of a climbing maneuver
- Not scanning for other traffic during the maneuver
- Performing by reference to the flight instrument rather than visual references
Commercial Pilot & Flight Instructor Test Questions
During training flights, an instructor should interject realistic distractions to determine if a student can maintain aircraft control while his or her attention is diverted.
Steep Turns
How should a student be taught to correct for a nose-low attitude during a steep turn? Reduce the angle of bank, then apply back elevator pressure to attain the desired pitch attitude.
If an accelerated stall occurs during a steep turn, in which direction would the aircraft tend to roll? The direction of roll depends upon whether the airplane is slipping, skidding, or in coordinated flight.
— In a slip or a skid, the airplane will tend rapidly roll in the direction opposite the slip/skid. In a coordinated turn, the stall will occur as in level flight, with the nose pitching down.
If an accelerated stall occurs in a steep turn, how will the aircraft respond? In a slip, the high wing stalls first; in a skid, the low wing stalls first; in coordinated flight, both wings stall at the same time.
Students should be taught that throughout a level 720° steep turn to the right, the rudder is normally used to prevent yawing.
Chandelles
Pilots who initiate a chandelle with a bank that is too steep will most likely perform a comparatively level steep turn with a nose-high rollout at the 180° point.
What may occur if the initial bank is too shallow when performing a chandelle? Stalling the aircraft before reaching the 180° point.
— If the initial bank in a chandelle is too shallow, the turn to the 90° point may take too long and the aircraft may lose too much airspeed, causing a stall prior to the 180° point.
When performing a chandelle, where should maximum pitch occur? 90° point.
Which best describes pitch and bank during the first 90° of a chandelle? Constant bank and changing pitch.
Which best describes pitch and bank during the second 90° of a chandelle? Constant pitch and changing bank.
Lazy Eights
When performing a lazy eight, when should the aircraft be a minimum airspeed? 90° point.
When performing a lazy eight, when should the maximum altitude occur? 90° point.
When performing a lazy eight, where should the maximum pitch-up attitude occur? 45° point.
When performing a lazy eight, where should the maximum pitch-down attitude occur? 135° point.
What should occur at the 90° point of a lazy eight? Steepest bank, minimum airspeed, maximum altitude, and level pitch attitude.
What would cause the 45° point to be reached before the maximum pitch-up attitude during a lazy eight? Beginning the turn with too rapid a rate of roll.
At what point in a lazy eight is it most likely necessary to exert opposing aileron and rudder pressures in order to maintain coordinated flight? At the point of slowest speed.
— When turning to the right, there is increased effective torque on the airplane when it's at its slowest speed. This isn't an adverse yaw question, it's a P-factor question.
What is the most probable result if a pilot initiates the climbing turn portions of the lazy eight with banks that are too steep? Turning at a rate too fast for the rate of climb, therefore completing each 180° change of direction with excessive airspeed.
Which is the most probable result if a pilot initiates the climbing turn portions of the lazy eight with excessive pitch? Attaining a pitch attitude that is too steep and stalling at the top of the climbing turn.