How do I determine the glide ratio for my aircraft?

There are multiple ways to obtain a glide ratio for an aircraft.

Option 1: A glide ratio value may be provided in the aircraft's Pilot's Operating Handbook (POH).

Option 2: An estimated glide ratio value can be interpolated from a Glide Range chart if one is provided in the POH.

Option 3: An estimated glide ratio value can be calculated if the POH provides information about a glide distance from an altitude at a certain speed. The glide ratio can be estimated by dividing the run by the rise after converting the distance (run) to the same unit value as the altitude (rise).

For example, if the POH indicates the aircraft can glide 1.5 NM for every 1000 ft of altitude lost at 85 knots, the following must be done.

1. Convert the rise and run values to the same unit. This example converts the 1.5 nautical miles (nm) to feet (ft). 1 nm is equal to 6076.12 ft. The math to convert the run to feet looks like this:

1.5 nm * 6076.12 ft = 9114.18 ft

2. Calculate the glide ratio. To do so, divide the run by the rise. The math looks like this:

9114.18 ft /1000 ft = 9.1

The glide ratio is 9.1:1. A more conservative glide ratio may be utilized.

Option 4: If no glide ratio information is available in the POH, contact the aircraft manufacturer to request glide ratio information.

Glide ratios can be entered in ForeFlight Mobile by going to More > Aircraft > Aircraft Profile.

Glide Ratio.PNG