Descent in vortex ring state can begin around 1000 to 2300 fpm and can rapidly reach about 5000 fpm.

Descent in vortex ring state can begin around 1000 to 2300 fpm and can rapidly reach about 5000 fpm.

• A. True
• B. False
• C. Cannot be determined
• D. Not enough information

Answer: (A)

Descent in vortex ring state happens when the rotor encounters its own downward rotor wash, so air is being recirculated through the rotor disc instead of flowing cleanly through it. That reduces rotor lift just as the helicopter is descending, creating a dangerous condition where the aircraft sinks faster than normal and rotor RPM can be compromised. In practice, this state can begin at descent rates around 1000 to 2300 feet per minute, especially with limited forward airspeed and high rotor loading. If the condition isn’t broken, the downwash recirculation can cause the descent to accelerate rapidly, reaching roughly 5000 fpm or more. The reason for the rapid escalation is that lift remains suppressed while the rotor continues to be fed with inefficient, recirculated air, so the aircraft sinks faster until it exits the downwash region. Recovery comes from increasing forward airspeed to pull out of the downwash and reducing collective to allow rotor RPM to recover, restoring lift and exiting the vortex ring state.

Descent in vortex ring state happens when the rotor encounters its own downward rotor wash, so air is being recirculated through the rotor disc instead of flowing cleanly through it. That reduces rotor lift just as the helicopter is descending, creating a dangerous condition where the aircraft sinks faster than normal and rotor RPM can be compromised. In practice, this state can begin at descent rates around 1000 to 2300 feet per minute, especially with limited forward airspeed and high rotor loading. If the condition isn’t broken, the downwash recirculation can cause the descent to accelerate rapidly, reaching roughly 5000 fpm or more. The reason for the rapid escalation is that lift remains suppressed while the rotor continues to be fed with inefficient, recirculated air, so the aircraft sinks faster until it exits the downwash region. Recovery comes from increasing forward airspeed to pull out of the downwash and reducing collective to allow rotor RPM to recover, restoring lift and exiting the vortex ring state.