A quick and easy way to figure it out is to start with your altitude above field elevation and multiply that number by three. This will give you the approximate distance in nautical miles from the airport to start a 500-foot-per-minute descent in the typical light general aviation airplane and reach pattern altitude.

When should you start descent?

As an example, if the airplane is flying at 30,000 feet the pilot should start the descent at 90 miles. Once the airplane is closer to the airport and the instrument landing system (ILS) can be used, the 3-degree descent is more finely tuned to touchdown.

How do you find the descent point?

A Visual Descent Point is found by subtracting the touchdown zone from the Minimum Descent Altitude and dividing the result by 300.