Lesson Plan
Performance Maneuvers: Lazy Eights
Purpose
Crop-dusting pilots use lazy eights as course reversals. It's an efficient way to execute 180° turns while dusting a field.
The purpose of the lazy eight is to develop the proper coordination of the flight controls across a wide range of airspeeds and attitudes. This involves the pilot developing a feel for the aircraft while it exhibits consistent and constant changes in control forces.
Elements
Flight controls are never constant: The lazy eight develops the proper coordination of the flight controls across a wide range of airspeeds and attitudes. Throughout the maneuver, flight controls are never constant.
Course reversals with climbs and descents: 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.
Select reference points: 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.
Maneuver entry: Gradual climbing 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 decreases, more rudder input will be required to counter left-turning propeller forces.
Avoid rapid roll entry: 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.
Avoid steep bank entry: 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.
The 90° point: 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.
Opposing aileron and rudder inputs: At 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.
Descending to the 135° point: On the descending portion of the turn, the bank should slowly roll out as the pitch attitude decreases.
Lowest pitch attitude: The lowest pitch attitude should occur at the 135° reference point.
Arriving at the 180° point: The wings and nose should be level at the original airspeed just as the 180° point is reached.
Change directions: A climbing turn is then started immediately in the opposite direction to complete the second half of the lazy eight.
Procedure
- Select a heading and an external reference
- Establish level flight at or below maneuvering speed (Va) or manufacturer's recommended entry speed Begin a gradual climbing turn is begun in the direction of the 45° reference point.
- At 45° reference point, establish maximum pitch-up attitude and 15° bank angle.
- At 90° reference point, level pitch attitude, 30° bank angle, and airspeed 5-10 knots above stall speed.
- At 135° reference point, lowest pitch attitude.
- At 180° reference point, a return to original airspeed and altitude.
Common Errors
Too much roll — too early: Beginning the turn with too rapid a rate of roll would cause the 45° point to be reached before the maximum pitch-up attitude.
Banks too steep — too much airspeed: If a pilot initiates the climbing turn portions of the lazy eight with banks that are too steep, the maneuver may be performed with turns that are at a rate too fast for the rate of climb. The result would be completing each 180° change of direction with excessive airspeed.
Too much pitch — stall: If a pilot initiates the climbing turn portions of the lazy eight with excessive pitch, the maneuver may be performed with a pitch attitude that is too steep, leading to a stall at the top of the climbing turn.
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
Completion Standards
Commercial Pilot & CFI Airmen Certification Standards (ACS)
- Select an altitude that will allow the maneuver to be performed no lower than 1,500 feet AGL.
- Maintain coordinated flight throughout the maneuver.
- Approximately 30° bank at the steepest point.
- Constant change of pitch and roll rate and airspeed.
- Altitude at 180° point: ±100 feet from entry altitude.
- Airspeed at the 180° point: ±10 knots from entry airspeed.
- Heading at the 180° point: ±10 degrees.
- Continue the maneuver through the number of symmetrical loops specified, then resume straight-and-level flight.
More Details
More details are available in the Airplane Flying Handbook
Lesson Plan Checklist
Lazy Eights