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What am I? E6B

Spin the wheel

There is something elegant about the circular slide rule.
Preflight July 2020
Photography by Mike Fizer

A masterful bit of engineering and design, the E6B combines all essential aviation calculations in a tidy package fit not for a shirt pocket, but a cockpit sidewall pocket.

The E6B was developed in the 1930s and is derived from centuries-old nautical tools. At its most essential the E6B makes quick work of flying’s trifecta of time, fuel, and distance. These three parameters are the foundation of all flight planning calculations, and a pilot can use the E6B to solve all three. There are also quick conversions, rulers for sectional charts, and more. And that’s just on one side of the rule.

The wind side is trickier to operate but includes a nifty way to quickly calculate the necessary wind correction angle and the groundspeed. With practice a pilot can spin the E6B wheels nearly as quickly as performing the same calculations with a digital calculator.

Which brings up the E6B’s downfall: technology. First came electronic E6Bs with their mindless button pushing, and now full-featured flight planning applications make any form of an E6B passé. But there’s no denying the genius simplicity of a cardboard, plastic, or metal wheel sliding along a scale to get all the information a pilot needs quickly and (with practice) easily.

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Types of whiz wheels

E6Bs come in a variety of materials and styles, but today they have largely been replaced by electronic flight bags.

Preflight July 2020Manual
The legacy E6B is made of cardboard, plastic, or metal and includes a calculation side of the wheel and a wind side.

Preflight July 2020Electronic
More or less a dedicated aviation calculator, electronic E6Bs perform all the same functions but without the need to understand the underlying methods.

Preflight July 2020Apps
Tablet apps such as ForeFlight and Garmin Pilot have largely replaced both manual and electronic E6Bs.

Ian J. Twombly

Ian J. Twombly

Ian J. Twombly is senior content producer for AOPA Media.

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