Which statement about dynamic rollover is true?

Which statement about dynamic rollover is true?

• A. It happens at zero yaw rate
• B. It relates to rotor RPM stability
• C. It occurs during hover only
• D. Occurs when lateral angular momentum around a pivot is excessive

Answer: (D)

Dynamic rollover is driven by the helicopter rolling about a ground contact point (a pivot such as a skid or wheel) while the lateral momentum about that pivot becomes too large to be arrested by the aircraft’s restoring forces. When the lateral angular momentum around that pivot is excessive, the rolling motion can accelerate and the helicopter can continue to tip over, even if the rotor thrust and rotor speed are fine. This is why that statement is the true one: the rollover risk arises from lateral inertia around a ground pivot, not from rotor RPM stability, and it is not limited to hover—it can occur during takeoff or landing as soon as one contact point is the hinge and lateral motion grows.

Dynamic rollover is driven by the helicopter rolling about a ground contact point (a pivot such as a skid or wheel) while the lateral momentum about that pivot becomes too large to be arrested by the aircraft’s restoring forces. When the lateral angular momentum around that pivot is excessive, the rolling motion can accelerate and the helicopter can continue to tip over, even if the rotor thrust and rotor speed are fine. This is why that statement is the true one: the rollover risk arises from lateral inertia around a ground pivot, not from rotor RPM stability, and it is not limited to hover—it can occur during takeoff or landing as soon as one contact point is the hinge and lateral motion grows.