Big Helicopter Rotor Brakes
Most Marine and Navy helicopters have rotor brakes. SASless is correct. Weight and complexity are issues. Both services have lost aircraft due to in flight rotor brake activations. These mishaps are due in part to the complexity of their systems. I believe that EH-Industries lost at least one prototype EH-101 due to an in flight rotor brake activation. Service life also enters into the equation. Rotor brakes are short lived at best. Large helicopter shipboard operations would be difficult without rotor brakes. As an example the H-53E rotor (2 tonnes) may coast for a very extended period of time without the help of a rotor brake to stop it.