It’s also handy to know at what rate your aircraft is climbing or descending. That’s where a vertical speed indicator comes in handy. When it points to 0 your plane is flying level. If the needle goes up to 5 you are climbing at a rate of 500 feet per minute (fpm). The rate of climb or descent is good to know so you can calculate how long it will take to reach a specific altitude. For example, if you’re flying at 3,500 feet MSL and you want to climb to 5,500 MSL you can control the aircraft to climb at a vertical speed of 500 fpm for four minutes.
The vertical speed indicator uses changes in air pressure to take a reading. Unfortunately, there is a lag of a few seconds between changing vertical speed and seeing it on the VSI. However, you will soon learn with experience how your sport plane responds and will adjust your control skills accordingly.