E6B Flight Computer

A manual circular slide rule (or its electronic equivalent) used by pilots for flight planning calculations including true airspeed, density altitude, fuel burn, time-speed-distance problems, and wind correction angles. The wind side of the E6B uses a sliding card and rotating disk to solve the wind triangle graphically. Despite the availability of electronic flight planning tools, proficiency with the E6B is required for the FAA knowledge test and is a valuable backup skill when electronic devices fail.