What does the Vertical Speed Indicator do?

• A. Measures air temperature
• B. Displays barometric pressure
• C. Senses changes in air pressure and displays them in the form of climb or dive rate from 0 to 6000 feet per minute
• D. Indicates heading

Answer: (C)

Vertical speed is about how fast you’re moving up or down, not how high you are. The Vertical Speed Indicator senses changes in static air pressure from the outside atmosphere and converts that pressure change into a climb or descent rate, shown in feet per minute. The mechanism responds to rapid pressure drops when you climb (the needle moves up) and pressure rises when you descend (the needle moves down), typically with a scale up to about plus or minus 6000 feet per minute. There’s a small lag due to the instrument’s internal damping, which is normal.

This instrument isn’t used to measure outside air temperature, and it doesn’t display barometric pressure or heading. Temperature is read by a separate sensor, barometric pressure is what the altimeter shows, and heading is provided by a directional instrument.