Deep Dive into Recovery Techniques from Vortex Ring State

Vortex Ring State is a dangerous loss-of-control phenomenon that can lead to excessive descent rates of up to more than 3,000 ft./min. within a few seconds from normal operations. Different recovery strategies are known and strongly discussed in the helicopter community and with the authorities, with a focus on minimising loss of altitude during the recovery and the level of piloting skills needed to perform such a maneuver efficiently. Here, physically accurate and flight-test–validated simulations of the maneuvers with state-of-the-art numerical simulations enable the factual comparative assessment of the different recovery techniques and provide guidance to close the long-lasting discussions about the different recovery techniques. The results are brought into context with other research initiatives of EASA/ONERA, the University of Stuttgart, and the FAA research center.