The vertical speed indicator (VSI) provides the rate of climb or descent of an aircraft. This instrument is crucial for pilots because it indicates whether the aircraft is gaining altitude or losing altitude and at what rate, typically measured in feet per minute. Knowing the vertical speed helps pilots make more informed decisions during various phases of flight, such as takeoff and landing, allowing them to maintain optimal performance and safety.
The VSI operates based on changes in air pressure resulting from altitude changes. As the aircraft climbs or descends, the pressure within the VSI changes, and the instrument needle moves to reflect the current vertical speed. This real-time information is essential for effective altitude management and situational awareness but does not provide details about fuel consumption, heading, or wind conditions, which are covered by other instruments.