What is the effect on Nr when interim power deactivates?

When interim power deactivates, the engine's output power capability is reduced, which directly impacts the rotor speed (Nr). Interim power is a state where the aircraft's system allows for a temporary increase in power output to support takeoff, climb, or other demanding tasks. Once this power is no longer available, the helicopter can only utilize the base power settings.

As a result, when interim power is deactivated, the rotor speed will reduce to normal operational levels, which is typically around 100% of the rotor speed. The rotor system is designed to operate efficiently within these limits, and maintaining Nr at this level ensures a balance between power and operational control.

This understanding is essential for pilots to manage the helicopter's performance during flight, particularly in transition phases where power management is crucial.