What happens to available RPM in a helicopter if there is significant ice formation?

When significant ice formation occurs on a helicopter, it adds weight and alters the aerodynamics of the rotor blades. Ice accumulation increases drag and reduces lift efficiency, leading to a decrease in the available engine power or RPM. This reduction in efficiency can push RPM levels to unsafe limits, particularly during critical phases of flight such as takeoff, hover, or landing. Pilots must be aware of these dangers, as inadequate RPM can compromise the helicopter's performance and control, potentially leading to hazardous situations. Recognizing this effect underscores the importance of ice detection and de-icing procedures in helicopter operations to maintain safety and performance.