Check the listing for details. VTG Aerodynamics APR E6-B flight Computer packet. Condition: Used. Listed at 22.99 USD. Aero Products Research Inc (APR) E6-B flight computer and related materials, such as an owner-registration card and a sectional chart. An E6-B is a type of circular slide rule used by pilots to perform various flight calculations. The E6-B flight computer is a mechanical calculator that helps pilots with calculations for speed, time, distance, fuel burn, altitude/speed correction, and wind drift. It was developed in the 1930s and is still used today, often for flight planning and during FAA written knowledge exams. The product is a vintage item from Aero Products Research, Inc. 1970’s. Similar E6-B computers are available from various manufacturers, including Sporty's, ASA, and others. Includes vtg. San Francisco map, world air chart & decals in bifold.