What thrust setting is used for a High Speed Straight Emergency Descent?

• A. NR 100%
• B. NR 104%
• C. NR 110%
• D. NR 95%

Answer: (B)

During a High Speed Straight Emergency Descent, the important idea is to keep rotor speed within a safe, energy-rich range so you maintain control authority as you descend. The governor keeps NR, the rotor speed as a percentage of maximum, within that band. Setting NR around 104% provides enough rotor energy to respond to the rapid changes in airspeed and attitude without pushing the rotor beyond its allowable limit.

Choosing NR at 100% leaves you at the lower end of the usable energy range, which can reduce responsiveness in a sudden descent. Pushing NR to 110% risks overspeeding the rotor and stressing the drivetrain and blades. Setting NR to 95% would again reduce rotor energy and degrade control stability during the maneuver.

So, NR 104% delivers the needed energy margin for a controlled, straight emergency descent while staying within safe operational limits.