FAA Ground School Practice Test

Which color indicates the power-off stalling speed in a specific configuration?

1. Upper limit of the green arc

2. Lower limit of the green arc

3. Red radial line

4. Yellow arc

The correct answer is: Lower limit of the green arc

The lower limit of the green arc on an airspeed indicator represents the power-off stalling speed for a specific configuration, such as clean configuration or landing configuration, depending on the aircraft and its operating manual. The green arc indicates the normal operating range of airspeeds for the aircraft, with the lower limit indicating the minimum speed at which the aircraft can be controlled. Once the aircraft descends below this airspeed, it reaches the point where a stall may occur if power is not applied to maintain sufficient lift. Understanding this concept is crucial for pilots to know the safe operational limits and avoid situations that could lead to a stall during flight. The other colors serve different purposes: the upper limit of the green arc indicates the maximum speed for normal operations, while the red radial line marks the never exceed speed. The yellow arc typically indicates that caution is recommended within that speed range; however, it does not specify stalling speeds.