With the PMU off, what is the maximum Np allowed?

The correct choice specifies that the maximum Np allowed with the PMU (Power Management Unit) off is 100 RPM, with a tolerance of plus or minus 2%. This value is significant to the operational limits of the aircraft, ensuring safe engine performance and preventing damage.

Operating within specified parameters is critical, especially for components like the PMU, which can influence RPM readings and control systems during flight. The tolerance range of 2% is also important, as it provides operators with a margin of operation that accounts for minor fluctuations or variances that can occur during engine performance assessments.

Understanding the reason behind setting the maximum Np at 100 RPM emphasizes the importance of adhering to manufacturer operational guidelines and the potential consequences of exceeding these limits, which could lead to engine strain or failure. This context reinforces the necessity for pilots and mechanics to be well-versed in the implications of RPM regulations in conjunction with engine management systems.