FAA Ground School Practice Test

As altitude increases, what happens to the indicated airspeed at which a given airplane stalls?

1. Increases with altitude

2. Remains the same regardless of altitude

3. Decreases with altitude

4. Varies based on weight

The correct answer is: Remains the same regardless of altitude

The correct understanding regarding stall speed is that it is primarily affected by the aircraft's design and configuration, including critical factors like weight, wing design, and load factor. As altitude increases, the indicated airspeed at which a given airplane stalls remains the same regardless of altitude because indicated airspeed is a measure that accounts for the air pressure and temperature changes with altitude. While true stall speed—known as true airspeed—does increase with altitude due to lower air density (which requires a higher speed to generate the same amount of lift), the indicated airspeed remains constant across various altitudes for a specific airplane at a specific weight and configuration. Pilots must be mindful that as altitude increases, the true airspeed at which the airplane stalls will increase, but the indicated airspeed on the aircraft's instruments will be the same, allowing pilots to accurately apply their stall recovery procedures at all altitudes. This concept is essential for safe flight operations, as understanding the relationship between stall speed and pressure changes will help pilots in maintaining control of the aircraft. The other options do not accurately capture the relationship between altitude and stall indication within an aircraft's operational parameters.