Certified Flight Instructor (CFI) Practice Exam

Stalling speed at minimum steady flight speed for controllability is denoted by which symbol?

1. Vso

2. Vs

3. Vx

4. Vr

The correct answer is: Vs

The symbol denoting stalling speed at minimum steady flight speed for controllability is indeed recognized as Vso. This speed is crucial because it represents the minimum speed at which an aircraft can be controlled in a clean configuration—specifically, with flaps and landing gear retracted. At this speed, the aircraft is close to a stall, meaning that it is operating at the edge of its performance envelope. Understanding this concept is vital for pilots, as it delineates the safe operating limits of the aircraft. Maintaining speed above Vso ensures that the pilot retains control even during scenarios where they might require quick maneuvers or in conditions that could lead to a stall. It's also critical during approach and landing phases, where pilots need to ensure their speed remains well above this threshold to ensure a safe operation. The other symbols pertain to different operational speeds: Vs represents the stalling speed in a specific configuration (often with some flaps extended), Vx is the speed for the best angle of climb, and Vr indicates the rotation speed at which the pilot will pull back on the yoke to take off. Each of these speeds has its own significance, but when discussing minimum steady flight speed for controllability, Vso is the standard reference.