This Aeronautical Standard covers two basic types of instruments@ or combinations thereof@ intended for use in indicating fuel consumption of aircraft engines as follows: TYPE I- Measure rate of flow of fuel used. TYPE II- Totalize amount of fuel consumed or remaining. Purpose: To specify minimum requirements for Fuel Flowmeters for use primarily in reciprocating engine powered civil transport aircraft@ the operation of which may subject the instruments to the environmental conditions specified in Section 3.3.