The VSI - what can it do for me?

In a nut shell, it can be one of the most useful instruments in your panel if you know how  to use it. 

Most people were taught that the VSI (vertical speed indicator) shows you the rate of climb or descent, but that it was mostly for reference because of the lag error in the instrument.  True, it takes about five to seven seconds to catch up to the actual rate of change, but this mind set completely ignores the fact that this is a trend instrument.  Using this “trend” or rate of change information can increase your ability to precisely control the airplane in many basic and advanced maneuvers.

The VSI is fairly sensitive to pressure changes, and will indicate that change almost immediately.  The altimeter responds to these pressure changes as well, but not as rapidly or as pronounced as the VSI when you deviate from a stable position.  Whether you are flying straight and level or in a steady climb/descent, any change in that rate, (level or otherwise) will be instantly indicated on the VSI.  Catching any unwanted change in this movement early is the key to maintaining precise control of the airplane.  This technique is especially useful for flying a near perfect steep turn or trimming for level flight.

Here’s a great exercise. From level flight adjust the trim significantly off of the normal trim.  Now try to maintain level flight by keeping the VSI at zero rate of climb for a little while.  It’s not as hard as it sounds and, with a little practice, it’s quite manageable.  From here it becomes very easy to retrim the airplane, gradually moving toward level flight without letting the VSI move off of zero.  This is the same technique you would use in a steep turn; just keep the needle at zero rate of climb.

You can also use the VSI to reference level flight. By that I mean you can use it to know when you are at a level pitch attitude.  This is very useful when flying on instruments.  Basically if the VSI needle is “moving”, then you need to pitch opposite its trend until it stops and reverses its movement. This technique takes a little more practice. Once you’ve pitched opposite the trend, you have to nurse it back to level flight to prevent oscillations up and down thru level flight.

With a little practice you will be amazed at how precisely you can maintain control of your pitch attitude with these techniques.