What must a pilot do if entering a vortex ring state (VRS)?

Entering a vortex ring state (VRS) can be an extremely dangerous situation for a helicopter pilot, characterized by descending at a high rate yet being unable to gain forward speed. In this scenario, the rotor blades encounter their own downwash, which can lead to a loss of lift and control.

When a pilot finds themselves in a VRS, entering autorotation is the most effective method to regain control and exit the condition. By entering autorotation, the pilot reduces the power being used to keep the rotor blades turning and allows the helicopter to become more responsive to control inputs. This helps to clear the rotor blades from the turbulent airflow created by the downwash, allowing the helicopter to regain lift and stability.

This approach contrasts with other options; simply increasing altitude would not be feasible or safe since the helicopter is already descending rapidly. Reducing lateral motion does not address the root cause of the problem, and maintaining current power settings during VRS would likely exacerbate the situation, keeping the helicopter in the state and potentially leading to a more severe loss of control. Thus, entering autorotation is the correct response to safely exit VRS and re-establish control of the helicopter.