Vuichard again

[SASless]

Page 11-9Vortex Ring State

Vortex ring state (formerly referenced as settling-with- power) describes an aerodynamic condition in which a helicopter may be in a vertical descent with 20 percent up to maximum power applied, and little or no climb performance. The previously used term settling-with-power came from the fact that the helicopter keeps settling even though full engine power is applied.

https://www.faa.gov/sites/faa.gov/fi...k/hfh_ch11.pdf