Rotor Brake Application Nr
SP, a slight amplification of your longer post on the subject.
As I am sure you are aware, types rated for naval shipboard applications have an emergency stop mode in that in an urgent situation the rotor brake can be engaged at 100% Nr. This is due to the need to accommodate sometimes very difficult conditions on rolling/pitching ships in strong gusty winds.
Examples are the naval EH101, the Sea King (SH3) and the Sea Hawk (SH-60). The requirement for this is described in a USN specification, SD-24L.
Unfortunately, I don't believe there is a web copy of that specification.