How to Calculate Glide Distance After an Engine Failure

Why glide distance matters

An engine failure turns every flight into a glider flight, planned or not. One question decides where you land: how far can the aircraft go from here, and is there a runway, a field, or at least open ground inside that circle? Glide distance answers it ahead of time during planning, or in the handful of seconds you actually have after the engine quits.

The glide distance formula

Still-air distance (nm) = height above the field (ft) × glide ratio ÷ 6,076.11549 (feet per nautical mile).
Sink rate (fpm) = best glide TAS (kt) × 6,076.11549 ÷ 60 ÷ glide ratio.
Time aloft (min) = height ÷ sink rate.
Glide distance with wind (nm) = (best glide TAS − headwind) × time aloft ÷ 60, taking a tailwind as a negative headwind.

Glide ratio — 9:1 means 9 ft forward for every 1 ft down — and best-glide speed both come straight from the POH, flown clean, at the weight the chart assumes. Fly faster or slower than best glide and the distance shrinks either direction; there's no clever way to beat the chart.

How to calculate it in E6B Calc

On E6B, open Glide under Performance.
Type your Height above the field in feet, for example your current altitude minus the field elevation.
Enter the Glide ratio from your POH, for example 9 for a 9:1 ratio.
Enter Best glide (TAS), the true airspeed for best glide at your weight.
Enter the Headwind. Use a negative number for a tailwind.
Read Glide distance, Still-air distance, Sink rate and Time aloft.

Worked examples

E6B Calc results; distances to 1 decimal
Height	Glide ratio	Best glide (TAS)	Headwind	Still-air distance	Sink rate	Time aloft	Glide distance
5,000 ft	9:1	75 kt	15 kt	7.4 nm	844 fpm	6 min	5.9 nm
5,000 ft	9:1	75 kt	0 kt	7.4 nm	844 fpm	6 min	7.4 nm
3,000 ft	10:1	65 kt	−10 kt (tailwind)	4.9 nm	658 fpm	5 min	5.7 nm
5,000 ft	9:1	75 kt	80 kt	7.4 nm	844 fpm	6 min	0.0 nm — No progress

Row three's 10 kt tailwind adds about 0.8 nm, the mirror case of the headwind above. Row four is the interesting failure: an 80 kt headwind against 75 kt best glide means the aircraft never actually moves forward over the ground, so the app says No progress rather than printing a negative number that would just confuse the issue.

Using it before you need it

Running this on the ground for your usual cruise altitude and home field, before it matters, gives a feel for the circle. In the air, typing height and wind takes seconds. Glide ratio and best glide speed are worth just memorising rather than looking up every time.

Common mistakes

Using the field elevation instead of the height above it. The app wants the difference.
Flying faster than best glide "to get there quicker": above or below best glide speed you glide less far, not more.
Forgetting the wind. A glide ratio chart alone assumes still air; the headwind or tailwind changes the real distance meaningfully.
Treating the glide ratio as fixed with flaps or gear down. Use the clean configuration figure from the POH unless yours gives another one.

Questions and answers

How do I calculate glide distance aviation-style, without the app?

Multiply height above the field by the glide ratio and divide by 6,076 to get nautical miles in still air, then shorten it for a headwind using the best-glide speed and the time aloft. The app does the same arithmetic and adds the wind correction.

What is a typical glide ratio for a light aircraft?

Many single-engine trainers glide around 8:1 to 10:1 clean; check your own POH, since it varies by type and sometimes by weight.

Does wind direction matter, or just speed?

Only the headwind or tailwind component along your glide track matters; a crosswind that does not line up with your track barely changes the distance. Enter the wind component you expect along the glide path.

Is the glide calculator free?

Yes, with no limits. Every performance calculator in E6B Calc, including Glide, Turn and Climb & Descent, is free.

How to calculate wind correction angle, true heading and ground speed · E6B Calc

How far can you glide after an engine failure?