Practice Autorotation
Common Errors:
- Inability to maintain steady-state Nr between 101–105% during descent.
- Failure to maintain balanced flight.
- Inconsistent or inappropriate airspeed in the descent.
- Abrupt nose-up flare, causing Nr spikes and unintentional climbs or a level speed change.
- Nose-high recovery, leading to transient Nr decay.
- Flying the maneuver primarily on instruments rather than visually.
- Lack of wind awareness.
- Recovering with yaw, drift, or misaligned heading.
- Skipping or inadequately performing the proper setup: full Before Landing Checklist, briefing callouts and wave off requirements, confirmation of appropriate aircraft weight (<18,500’), and local mandates (e.g., crash/fire readiness).
Teaching Techniques:
- Maintain Nr between 101–105% to simulate a true autorotation. If Nr is at or below 100%, the aircraft is still in powered flight. Emphasize a complete collective reduction followed by an immediate small check, then fine-tune collective in the descent to stay in the correct Nr range (typically, collective full down, a couple inches of check to stop Nr from building, then another small lowering of the collective to obtain a steady Nr of 102-103%).
- Encourage students to key into audible Nr changes for situational awareness.
- When entering autorotation, simultaneous inputs are required:
- Collective full down.
- Pedals adjusted (typically right pedal).
- Cyclic input (usually forward). Students often miss that nose attitude changes, even though airspeed hold remains engaged. If you liked your entry airspeed, don’t re-trim—use cyclic against the trim to help the autopilot regain set speed.
- Turns increase g-load, which raises Nr. During a turn, check Nr with a small collective input; as wings level, lower collective to stay above 100% Nr and avoid entering powered flight.
- The flight manual prescribes a progressive flare to 20–30° nose high. However, students often “snap” the nose up, causing an Nr spike, level-off, or even a brief climb. This keeps the aircraft high and results in a vertical descent to recovery altitude—an undesirable condition in a real auto scenario.
- Emphasize a true progressive flare:
- Increase pitch gradually.
- Understand that the rate of pitch increase rises as airspeed decreases.
- Preemptively check collective to manage rising Nr. The goal is to decelerate and descend—not level off or balloon.
- As the flare expends kinetic energy, lower the collective to prevent power from the engines driving the rotor (a common issue in practice autos). In real autos, this action preserves Nr as airflow through the rotor decreases.
- Be mindful of the narrow weight band for practice autos (roughly 18,500–17,000 lbs.). Students may develop a robotic flare technique that only works at light weights. In real-world scenarios (e.g., an auto at 21,500 lbs., a flare initiated at 120 KIAS, etc.), feel and finesse in the progressive flare will yield far better results.
- During power recovery, failing to lower the nose to a landing attitude can be a critical error. Nose-high attitudes tilt the lift vector, requiring more power to stop the descent. Additionally, engine spool up lags when transitioning from high Nr to a high-power demand. Even when limiting Nr to 105%, there will be a delay in power production. Nr can decay rapidly, often dropping into the mid-90s. Combined with a nose-high attitude, this can lead to mushing through the 20’ cushion and tail strikes.
- Nr is limited to 105% during the practice autorotations due to the lag in engine spool up. The engines do not respond until Nr drops to 100% (or the set Nr reference), so exceeding 105% can cause a delay in the ability to perform a power recovery.
- In prior autorotation training (e.g., TH-57 to touchdown), level attitude and smooth collective application were key to successful landings. Abrupt or poorly timed pitch inputs consumed rotor energy prematurely, resulting in hard touchdowns. Though the TH-57 and H-60 differ, the principles of rotor energy management remain the same.