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Composition of JET B turbine fuel

Aviation Mechanic General (AMG) practice question 26 of 26 on Ground Operations and Servicing. ACS element AM.I.F.K9 · difficulty: recall. Want to answer it in a timed quiz? Use the Aviation Mechanic General (AMG) practice mode.

Question bank updated 2026-09-22

QUESTIONOf the turbine fuels generally used in civilian aviation, JET B is made up of what?

  1. AA blend of kerosene and AVGAS
  2. BKerosene only, the same as JET A
  3. CA grade of AVGAS used in large aircraft
Show the answer and explanation

Correct answer: A. A blend of kerosene and AVGAS

  • A — correct The handbook lists three turbine fuels in general civilian use: JET A and JET A-1, made from kerosene, and JET B, which is a blend of kerosene and AVGAS.
  • B — incorrect JET A and JET A-1 are the fuels made from kerosene alone; JET B is distinguished from them because AVGAS is blended in.
  • C — incorrect JET B is a turbine fuel, not an AVGAS grade; the AVGAS grade associated with large reciprocating-engine aircraft is 115/145, which is in limited use.

BACKGROUND

Aviation fuel falls into two broad families: aviation gasoline (AVGAS) for reciprocating engines, and turbine fuel (jet fuel) for turbojet and turboshaft engines. The handbook names three turbine fuels in general civilian use: JET A and JET A-1, both made from kerosene, and JET B, a blend of kerosene and AVGAS. Jet fuel is identified by the color black on piping and fueling equipment, although the fuel itself can be clear or straw colored. AVGAS, by contrast, is identified by grade numbers such as 80/87, 100/130, and 100LL, where the two numbers give the lean mixture and rich mixture octane ratings. Knowing which family a fuel belongs to matters because the handbook cautions against mixing AVGAS and jet fuel and directs a mechanic to the Type Certificate Data Sheet for the respective powerplant before any mixing.

STUDY TIP

Memorize the three civilian turbine fuels as a set and note that only JET B contains AVGAS. Pair that with the AVGAS grade list so you do not confuse a turbine fuel designation with a gasoline grade.

KEY POINTS

  • Civilian turbine fuels in general use are JET A, JET A-1, and JET B.
  • JET A and JET A-1 are made from kerosene; JET B is a kerosene and AVGAS blend.
  • AVGAS grades such as 80/87, 100/130, and 100LL belong to reciprocating engines, not turbines.

SOURCES

  • FAA-H-8083-30B ch01 "Types of Fuel and Identification"
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SkyDrill is not affiliated with the FAA. This is an original practice item based on FAA-H-8083-30B Aviation Maintenance Technician Handbook – General, 14 CFR part 43 and part 65. Regulations and handbooks are revised; confirm details against the current edition.