For an aircraft to operate reliably in every phase of flight and in all expected environments, its fuel system must store and maintain a sufficient quantity of fuel and deliver it to the powerplant without interruption or contamination. The entire fuel system can be divided into three functional areas: storage, delivery, and distribution.
The earliest systems were very simple, including a tank, fuel lines, a selector valve, and a carburetor. Over time, powerplant technology advanced, and with increased power came more complexity and more specific demands for distributing fuel. Fuel systems are designed to efficiently meet the design requirements of an aircraft powerplant with particular considerations for safety. Aviation maintenance technicians must be thoroughly familiar with the design, operation, and maintenance of the aircraft fuel system before inspecting or performing maintenance.
Aircraft fuel systems have two basic sections: airframe and powerplant. The airframe section consists of all the parts associated with storage and delivery, including the components from the fuel tanks to the engine-driven pump. The powerplant section consists of the distribution parts, beginning after the engine-driven fuel pump and concluding at the point where air and fuel are mixed for combustion.
The following posts in this series introduce the fundamental requirements, mechanical designs, and maintenance procedures for both reciprocating and turbine engine fuel metering systems.
Engine Fuel and Fuel Metering Systems Series
1. Fuel System Requirements
Learn the mandatory safety and performance standards for aircraft fuel storage and delivery.
2. Basic Fuel System
Study the fundamental layout of gravity-feed and pressure-feed fuel system configurations.
3. Fuel Metering Devices
Understand the evolution and function of metering units in reciprocating engines.
4. Carburetion Principles
Explore the physics of Venturi effect, pressure differentials, and air-fuel ratios.
5. Carburetor Systems
Study the auxiliary systems including idling, acceleration, and power enrichment circuits.
6. Carburetor Types and Icing
Understand the various carburetor designs and the critical hazards of fuel evaporation ice.
7. Float Type Carburetors
Explore the mechanical operation of float mechanisms and needle valves in fuel regulation.
8. Pressure Injection Carburetors
Learn about pressurized fuel metering and the role of Automatic Mixture Control (AMC).
9. Stromberg PS Carburetor
Study the specific operation and maintenance of the Stromberg pressure-type carburetor.
10. Fuel Injection Systems
Understand the benefits and mechanics of direct fuel injection in modern aircraft engines.
11. Carburetor Maintenance
Learn the procedures for cleaning, adjusting, and troubleshooting carburetor installations.
12. System Inspection & Maintenance
Explore the best practices for inspecting fuel lines, filters, and airframe delivery components.
13. Turbine Fuel Requirements
Understand the high-volume and high-pressure demands of modern gas turbine fuel systems.
14. Fuel Control Maintenance
Study the calibration and servicing of complex hydro-mechanical and electronic fuel controls.
15. Engine Fuel Components
Explore the hardware including pumps, heaters, valves, and nozzles used in fuel distribution.