FAA Private Pilot Helicopter (PRH)Performance and LimitationsMedium
Increasing a helicopter's gross weight prior to an autorotation will primarily result in
- Ano change in autorotative characteristics
- Ba slower rate of descent and more time to select a landing area
- Can automatic increase in rotor RPM
- Da higher rate of descent and less rotor RPM control margin
Show answer & explanationAnswer & explanation
Correct answer: D. a higher rate of descent and less rotor RPM control margin
A higher gross weight increases the rate of descent during autorotation because more airflow through the rotor disk is needed to maintain rotor RPM, and it reduces the margin available to control rotor RPM, making the autorotation and flare more critical.
Why the other options are wrong
- A. Gross weight has a well-documented and significant effect on autorotative performance.
- B. Increased weight has the opposite effect—descent rate increases, not decreases.
- C. Rotor RPM does not automatically increase; it must be actively managed by the pilot with collective.
Gross Weight Effect on Autorotation
Higher gross weight increases the rate of descent in autorotation and reduces the margin for controlling rotor RPM, making energy management during the flare more critical.
- Heavier weight requires more upward airflow to maintain rotor RPM
- Descent rate increases with gross weight in autorotation
- Flare timing and technique become more critical at higher weights
Memory trick: Heavier helicopter falls faster and needs a sharper flare.