E6B Flight Computer

This solves the parts of an E6B flight computer that are exact arithmetic. The wind triangle gives the heading to hold a course and the ground speed you will make, and runs backwards to find the wind from a heading, a track and a ground speed. The airspeed tab turns calibrated airspeed, pressure altitude and outside air temperature into true airspeed, Mach and density altitude through the ICAO Standard Atmosphere, using the compressible flow relations rather than the two percent per thousand feet shortcut. A fourth tab covers leg time, fuel burn and reserves. It is a desk tool for planning and study, not for navigating in flight.

Calculator Type
Fuel Measured In
The track you want to make good over the ground, measured from true north. Everything on this page is true, not magnetic.
Work it out on the true airspeed tab if all you have is the indicated figure.
A forecast or written METAR wind is true. A wind read to you by a tower or on ATIS is magnetic, so correct it for variation first.
Knots, as a METAR, TAF or winds aloft forecast gives it. If yours reports metres per second, multiply by 3.6 and divide by 1.852, a knot being 1.852 km/h exactly.
Leave at 0 to get the heading and ground speed on their own. Nautical miles, to match the knots above; a nautical mile is 1.852 km exactly, so divide kilometres by that.
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Where the nose was pointing, in true degrees.
The line actually flown over the ground, off the GPS or from two fixes.
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Indicated airspeed corrected for position and instrument error, from the table in the flight manual. On most light aircraft in cruise the two are within a knot or two of each other, but near the stall they are not.
What the altimeter reads with 29.92 inHg or 1013 hPa set in the window. Above the transition altitude your flight level already is the pressure altitude. Feet, because a flight level is defined as hundreds of feet; if you are reading a metric altimeter, divide the metres by 0.3048.
The static air temperature. A probe on a fast aeroplane reads high because the air stagnates on it, and that ram rise is not corrected for here.
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Fuel Measured In
Nautical miles, to match the ground speed in knots below. A nautical mile is 1.852 km exactly, so divide kilometres by that figure. The fuel boxes further down do offer gallons, litres or pounds.
The ground speed for this leg, which the wind triangle tab works out from your true airspeed and the wind.
Usable, not total. The unusable fuel in the tanks is not available to the engine at any attitude.
Whatever the rule you fly under and your own minimum require. Set it to 0 to see the bare trip fuel.
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Related Tools
Speed Distance Time Calculator Flight Time Calculator Crosswind Calculator Dew Point Calculator Density Altitude Calculator