What is the NR Power-On Transient percentage limit for a maximum duration of 10 seconds?

• A. 90%
• B. 103%
• C. 108%
• D. 110%

Answer: (C)

The NR Power-On Transient percentage limit for a maximum duration of 10 seconds is 108%. This limit is established to ensure safe operation of the rotor system during transient conditions, which may occur during specific flight maneuvers or power changes.

When the helicopter's power is increased rapidly, the rotor speed (NR) can momentarily exceed the normal operating envelope. The 108% limit indicates the maximum acceptable rotor speed that can be sustained briefly without risking damage or compromising safety. This limit is critical for pilots to understand, as exceeding it for extended periods can lead to rotor system stress, potential failure, or unwanted vibrations, which could jeopardize flight safety.

Remaining aware of these transient limits is part of maintaining control and ensuring the integrity of the aircraft during dynamic flight operations. The other values mentioned in the options either represent unsafe limits for extended durations or levels that do not align with the parameters established in the NATOPS for safe helicopter operation.