Aircraft Fuel Systems
Aircraft Fuel Systems is a core knowledge area on the AMT — Airframe FAA written exam. This hub collects our 16 in-depth, ACS-aligned aircraft fuel systems articles — each written in plain English and grounded in the official FAA handbooks. Work through them below, then drill the topic with practice questions.
Aircraft Fuel Tank Types: Integral, Bladder, and Rigid
Aircraft fuel tanks come in three main designs—integral, bladder, and rigid removable—each with distinct construction, maintenance, and inspection requirements critical for AMT certification.
Fuel System Venting Requirements and Vent Line Design
Proper fuel system venting prevents dangerous pressure imbalances that can collapse tanks, block fuel flow, or create vapor lock — making vent line design a critical airframe maintenance topic.
Aviation Fuel Grades and Color-Coding Standards
Aviation fuels are precisely color-coded and graded to prevent misfueling, with each grade matched to specific engine requirements and identified by standardized colors used throughout the fuel supply chain.
Gravity-Feed vs. Pressure-Feed Fuel System Configurations
Gravity-feed systems rely on fuel tank height above the engine; pressure-feed systems use pumps to overcome gravity and feed distance — understanding both is critical for airframe maintenance and airworthiness.
Fuel Selector Valves: Types, Operation, and Inspection
Fuel selector valves control the flow of fuel from tanks to the engine; understanding their types, operation, and inspection is essential for airframe technicians and safe aircraft operation.
Fuel Filters, Strainers, and Sediment Bowl Inspection
Fuel filters, strainers, and sediment bowls are the last line of defense against contamination reaching the engine; understanding their inspection and maintenance is critical for any airframe technician.
Fuel Quantity Indicating Systems: Float, Capacitance, and Sight Gauges
Fuel quantity indicating systems — float-type, capacitance, and sight gauges — tell pilots and mechanics how much fuel is aboard; understanding how each works and where each fails is essential for airworthiness and exam success.
Crossfeed and Transfer Fuel System Plumbing
Crossfeed and transfer fuel systems allow pilots and maintenance technicians to manage fuel distribution across multiple tanks, preventing imbalance, extending range, and ensuring engine reliability in multi-engine and large aircraft.
Fuel System Water Contamination: Detection and Prevention
Water in aviation fuel is a leading cause of engine failure; AMT candidates must know how water enters fuel systems, how to detect it, and the procedures that keep aircraft safe.
Boost Pumps and Engine-Driven Fuel Pump Operation
Boost pumps and engine-driven fuel pumps work together to deliver reliable fuel flow; understanding their roles, failure modes, and operational logic is essential for airframe AMT certification and safe aircraft maintenance.
Bladder Fuel Tank Inspection, Repair, and Replacement
Bladder fuel tanks are flexible, removable liners used in many general aviation aircraft; understanding their inspection criteria, approved repair methods, and replacement procedures is essential for airframe technicians and the FAA knowledge test.
Fuel System Bonding and Grounding for Static Discharge Prevention
Proper bonding and grounding of aircraft fuel systems prevents static electricity buildup that can ignite fuel vapors during servicing and flight, making it a critical safety and regulatory requirement for all AMTs.
Fuel Jettison Systems: Design, Operation, and Regulatory Requirements
Fuel jettison systems allow large transport-category aircraft to rapidly reduce weight below maximum landing limits, preventing structural overloads during emergency returns to the field.
Fuel Drain Valves: Types, Locations, and Preflight Sampling Procedures
Fuel drain valves are critical safety devices that allow pilots and technicians to sample fuel for contamination and water before every flight; understanding their types, locations, and proper sampling technique is essential for airframe maintenance and preflight airworthiness.
Aviation Fuel Anti-Icing Additives and Fuel Heater Systems
Aviation fuel anti-icing additives and fuel heater systems prevent ice formation in aircraft fuel systems, protecting engine flow and reliability in cold or high-altitude operations.
Integral Wet Wing Fuel Tank Sealing and Leak Repair
Integral wet wings use the sealed aircraft structure itself as the fuel tank, requiring specialized sealants, inspection techniques, and repair procedures to prevent leaks and maintain airworthiness.
More AMT — Airframe subjects
Articles are original summaries grounded in the public-domain FAA handbooks and cite their source. ACS-aligned study aids — not a substitute for the official handbooks or regulations.