Aircraft Fuel Systems Repair Key Terms

Learn some basic aircraft fuel systems vocabulary

By Cathy Salustri

Aircraft fuel systems have some industry-specific terms that you won't hear when discussing other types of vehicles. Some of these terms, like air-to-fuel ratio, make sense to most people with some knowledge of piston engines. Others, such as airframe and powerplant, may not make as much sense. Learning some of these terms will help you better understand what's going on with your company's aircraft and its fuel system.

Airframe and powerplant mechanic (A&P)

An airframe and powerplant mechanic (A&P) receives special training and certification to work on aircraft, including fuel systems. The Federal Aviation Administration (FAA) regulates what sort of training an A&P must have to retain certification.
Try: The United States Department of Labor explains what an A&P does and what kind of training they receive.

Aviation jet fuel

Aviation jet fuel has several different incarnations. Jet-A, Jet-B, JP-4, JP-5 and JP-8 are all different types of aviation jet fuels. Each type of aviation jet fuel has a different purpose as well as distinct defining characteristics.
Try: CSG lists the different types of aviation jet fuels. It also defines each type of fuel and explains the differences, uses and additives.

Aviation gasoline (AVGAS)

Aviation gasoline (AVGAS) is different from aviation jet fuel. It has a higher octane rating (100) than car gasoline and has lead added to it. AVGAS is used in airplanes with piston engines.
Try: To understand more about AVGAS and how it works, read more at Shell.

Detonation

Detonation occurs when the fuel-air mixture does not burn smoothly in the engine's cylinder, exploding because it gets too hot too fast. This can harm the cylinder in your aircraft engine.
Try: To better understand detonation, its contributing factors and related conditions, read the explanation from Experimental Aircraft Information.

Air-to-fuel ratio

Air-to-fuel ratio, also known as A/F or AFR, refers to how much air and fuel is in the aircraft engine as it runs. Pilots can adjust the AFR with the plane's mixture.
Try: Learn more about AFR and the relationship between fuel and oxygen at Cygnus Interactive.

Usable fuel

Usable fuel refers to the amount of the fuel your aircraft can use. For example, your business aircraft my have a capacity for 26 gallons of fuel in each wing but the usable fuel will be slightly less.
Try: To learn how to calculate the weight of the usable fuel on your aircraft, use the formula provided in the aviation glossary at J. Mesinger Corporate Jet Sales.