This SAE Aerospace Standard (AS) defines the maximum allowable free opening dimensions for airframe fueling ports on civil aircraft that require the exclusive use of gasoline as an engine fuel@ and the minimum free opening dimensions for airframe fueling ports on civil aircraft that operate with turbine fuels as the primary fuel type and with gasoline as the emergency fuel type. This SAE Aerospace Standard (AS) also defines the features and dimensions for airframe refueling ports on civil aircraft that require the exclusive use of turbine fuel as an engine fuel. In addition@ this document defines the minimum fuel nozzle spout dimensions for turbine fuel ground service equipment@ and the maximum fuel nozzle spout diameter for gasoline ground service equipment. Purpose: This document establishes the essential interface dimensions for airframe fueling ports and ground fueling nozzle spouts that are intended for use on civil aircraft with gravity fuel servicing provisions. Primary intent of the standardized interface limits and features detailed in this document is the prevention of misfueling civil aircraft that require the exclusive use of a single aviation fuel type for safe operation.