In which flight control ranges does the EPECS set the prop RPM to 1700?

• A. Takeoff range or beta/reverse range
• B. Cruise range or climb range
• C. Idle range or approach range
• D. Taxi range or takeoff range

Answer: (A)

Propeller RPM is controlled by the flight control ranges to match the needed performance. The EPECS uses the high takeoff setting of about 1700 RPM when you’re in takeoff range, giving maximum thrust for a short, powerful acceleration. It also keeps the prop at 1700 RPM in the beta/reverse range so that reverse thrust is available and controllable for ground operations and braking.

In other ranges—cruise, climb, approach, idle, and taxi—the system tunes the propeller differently to balance fuel economy, noise, smoothness, and control. Those regimes don’t require the high takeoff RPM, so the RPM is set to other values appropriate for that phase of flight.