What is the cautionary N1 range during autorotation?

• A. 45-50%
• B. 51-56%
• C. 51-60%
• D. 57-60%

Answer: (C)

The cautionary N1 range during autorotation in the TH-73A is identified as 51-60%. This range is critical for pilots to monitor because operating within it can help ensure the engine remains within safe parameters during the critical phase of autorotation.

When performing an autorotation, maintaining the N1 in this cautionary range allows pilots to assess their engine performance and prepare for potential engine failure scenarios. Operating in this range also helps maximize rotor efficiency and maintain sufficient rotor RPM, which is crucial for a successful landing without power.

Understanding the importance of these engine parameters helps pilots make informed decisions regarding their aircraft's performance and safety in various flight conditions.