If NR is exactly 345 RPM, will an aural warning occur?

If NR is exactly 345 RPM, will an aural warning occur?

• A. No
• B. Only if NR is below 345
• C. Only if NR is above 345
• D. Yes

Answer: (D)

The main point is how the low rotor-speed warning works. The aural warning is triggered whenever NR falls below the fixed minimum NR limit defined for safe operation. In the MH-65E, that minimum is above 345 RPM, so when NR is exactly 345 RPM you’re already below the required minimum and the warning will sound. If NR were above the limit, there would be no warning; if it were below the limit, the warning would also occur. So at 345 RPM, the alert is active.

The main point is how the low rotor-speed warning works. The aural warning is triggered whenever NR falls below the fixed minimum NR limit defined for safe operation. In the MH-65E, that minimum is above 345 RPM, so when NR is exactly 345 RPM you’re already below the required minimum and the warning will sound. If NR were above the limit, there would be no warning; if it were below the limit, the warning would also occur. So at 345 RPM, the alert is active.