What information does a vertical velocity indicator provide?

A vertical velocity indicator, often referred to as a VSI, is specifically designed to measure and display the rate of change in altitude of an aircraft. It provides pilots with crucial information regarding whether they are climbing or descending, and at what rate, typically expressed in feet per minute. This information is vital for maintaining a safe and controlled ascent or descent during flight operations.

While the vertical axis relates to orientation, the vertical velocity indicator does not provide indications regarding rotational speed around any axis, fuel consumption, or the angle of ascent or descent. Instead, it quantifies the actual rate at which the aircraft is gaining or losing altitude, making it an essential tool for pilots in managing their altitude changes safely and effectively.