Vortex ring state descent can initiate at 1000 to 2300 fpm and rapidly build to 5000 fpm.

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

Answer: (D)

Vortex ring state happens when a helicopter descends into its own downwash with little forward airspeed, so the rotor is recirculating air instead of producing effective lift. Because the rotor is effectively fighting against the strong downward flow, lift decreases and the descent can accelerate rapidly. In practice, this condition can begin at relatively high descent rates—about 1000 to 2300 feet per minute—especially when forward speed is minimal. Once VRS starts, the flow field around the rotor worsens the loss of lift, and the descent can quickly climb to several thousand feet per minute, sometimes up to around 5000 fpm, until corrective action restores forward airspeed and rotor efficiency. The statement reflects the realistic behavior of VRS, which is why it is considered true.