What airspeed must be reduced below to reactivate interim power?

To reactivate interim power, the required condition is for the airspeed to be reduced below 55 KCAS. This specific airspeed requirement is crucial for ensuring that the aircraft remains within safe operational limits while allowing the system to engage interim power effectively.

Interim power is a temporary boost in power available for flight maneuvers, particularly when the aircraft needs increased thrust and efficiency in situations like climb or during combat operations. By setting this threshold at 55 KCAS, the design ensures that the aircraft's performance is optimized without exceeding operational parameters that could lead to instability.

The choices provided all represent airspeeds, but only reducing below 55 KCAS allows the necessary conditions for interim power to be safely activated. This knowledge is critical for maintaining control and ensuring effective engine performance under various flight circumstances.