Aircraft Fuel Systems — FAA A&P Test Questions (ACS AM.II.J)
Aircraft Fuel Systems is the Airframe area covering everything between the tank and the engine's fuel inlet: tanks and sumps, boost and engine-driven pumps, selector and crossfeed valves, strainers, lines, quantity indicating and the fuels themselves. The FAA tests it as a plumbing and contamination subject. Expect questions on why fuel reaches the engine in a gravity system, what a sump drain is for, how water and sediment are found, what vapor lock actually is, and why aviation gasolines are dyed by grade. This page maps the area and drills the published questions.
Written by the AMTprep editorial team · Published · Last reviewed
Written against the FAA primary sources cited at the foot of this page.
What ACS AM.II.J covers
Start with the tank. Integral wet-wing, bladder and rigid removable tanks all need a sump at the lowest point, because water is heavier than fuel and settles there; the sump drain valve lets you take a sample before flight. The expected answer for finding water is a drained sample in a clear container, not a gauge reading and not the strainer, since a strainer or filter catches solid contaminants and passes water straight through. Delivery is the next block. A gravity-feed system works because the tanks sit above the engine and the head pressure of the fuel column alone moves fuel to the carburetor, so no pump is required. Pressure-feed systems use an engine-driven pump as the normal in-flight supply, with an electric boost pump for starting, takeoff and landing, high-altitude operation and as a backup if the engine-driven pump fails. Questions separate those two roles carefully. Selector and crossfeed valves, firewall shutoff valves, strainers and drains, quantity indicating and jettison systems fill out the hardware. Then the fuel itself. Vapor lock is fuel vaporizing inside the lines so vapor pockets interrupt liquid flow, driven by heat, low pressure and volatility. Running the boost pump raises line pressure and pushes vapor back toward the tank, which is why boost pumps are used at altitude and on hot restarts. Aviation gasolines are dyed by grade, 100LL blue and grade 100 green, so you can confirm what went into the tank and spot mixing or contamination in a sample. Jet fuel carries no dye and looks clear to straw. FAA-H-8083-31 is the supporting reference, and fueling, defueling, bonding and tank-entry safety are tested alongside the hardware.
Where this sits on the test
ACS AM.II.J is tested on the FAA Airframe written test, one of 1,739 ACS-tagged questions in the Airframe bank. Every question tagged to this area carries a worked rationale and its FAA handbook reference, so you can drill the code itself rather than the whole test.
FAA handbook references
- FAA-H-8083-31
Three traps candidates fall into
- The engine-driven pump gets treated as the backup and the boost pump as the main supply. In a pressure-feed system it is the other way round: the engine-driven pump is the normal in-flight source, and the electric boost pump covers start, takeoff, landing, high altitude and engine-pump failure.
- Fuel dye colors get reversed. 100LL is blue and grade 100 is green, not the other way around. Worse, candidates read a colorless sample as clean avgas. Jet fuel carries no dye at all, so clear or straw-colored fuel drained from an avgas tank is a misfueling clue, not a pass.
- Vapor lock is read as air trapped in the lines. It is the fuel itself flashing to vapor because of heat, low pressure or a volatile grade. That is why the fix is pressure, with the boost pump raising line pressure and moving vapor back to the tank, rather than bleeding air out of a fitting.
44 free sample questions from ACS AM.II.J
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In a typical aircraft reciprocating-engine fuel system, what is the primary purpose of the engine-driven fuel pump?
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Answer: To supply fuel under pressure to the carburetor or fuel injection system during normal engine operation
Why: The engine-driven fuel pump is the main pump in a gravity-independent system; it delivers fuel under pressure to the metering device (carburetor or injection unit) whenever the engine is running. Venting is handled by the tank vent system, and metering of the air-fuel ratio is the job of the carburetor or fuel injection system, not the pump.· FAA-H-8083-31 — Aircraft Fuel Systems (fuel pumps)
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What is the purpose of the fuel tank sump and its drain valve?
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Answer: To collect water and sediment at the lowest point of the tank so they can be drained off
Why: The sump is a low point in the tank where water (heavier than fuel) and sediment settle and collect. A drain valve at the sump lets the mechanic or pilot drain off the contaminants during preflight or maintenance. It is not a pressure-relief device, and the vent connects to the top of the tank, not the sump.· FAA-H-8083-31 — Aircraft Fuel Systems (tank sumps and drains)
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During a fuel system pre-flight check, water contamination in a tank is most reliably detected by
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Answer: draining a fuel sample from the lowest sump and checking for separated water
Why: Water is heavier than aviation fuel and settles to the lowest point in the tank, the sump. Draining a sample from the sump drain lets the mechanic see water as a separate layer or clear globules at the bottom of the sample. Fuel quantity gauges and line temperature are not reliable indicators of water contamination.· FAA-H-8083-31 — Aircraft Fuel Systems (contamination/sump sampling)
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In a gravity-feed fuel system, fuel flows to the engine because
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Answer: the fuel tanks are mounted above the carburetor and gravity moves the fuel downward
Why: A gravity-feed system relies on the tanks being located higher than the carburetor, typically in a high-wing aircraft, so fuel flows downhill to the engine without a pump. Suction-lift from a pump describes a pressure-feed system, and tank pressurization is not used in simple gravity-feed designs.· FAA-H-8083-31 — Aircraft Fuel Systems (gravity-feed systems)
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What is the purpose of a strainer or filter in an aircraft fuel system?
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Answer: To trap dirt, water, and other contaminants before fuel reaches the metering system
Why: The main fuel strainer or filter removes solid contaminants and helps separate water before fuel reaches the carburetor or injection unit, protecting downstream components. Filters do not raise fuel pressure, and vaporizing fuel is a function of the carburetor venturi and intake, not the strainer.· FAA-H-8083-31 — Aircraft Fuel Systems (strainers and filters)
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Vapor lock in a fuel system is best described as a condition in which
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Answer: fuel vaporizes in the lines and the resulting vapor bubbles interrupt the flow of liquid fuel
Why: Vapor lock occurs when fuel in the lines vaporizes, usually from excessive heat or low pressure, forming vapor bubbles that block or interrupt the flow of liquid fuel to the engine. Ice in the filter is a separate icing problem, and a stuck selector valve is a mechanical malfunction, not vapor lock.· FAA-H-8083-31 — Aircraft Fuel Systems (vapor lock)
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When servicing a fuel system, the use of a boost pump to clear vapor from the lines helps prevent vapor lock primarily because it
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Answer: raises the pressure in the lines, which keeps the fuel in a liquid state
Why: Increasing line pressure raises the temperature at which the fuel will vaporize, so a boost pump that pressurizes the lines keeps fuel in liquid form and suppresses vapor lock. The pump does not freeze the fuel, and removing dissolved water is a function of filters and sumps, not vapor-lock prevention.· FAA-H-8083-31 — Aircraft Fuel Systems (vapor lock prevention)
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Aviation gasolines are dyed different colors primarily so that a mechanic can
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Answer: identify the grade of fuel and detect mixing of different grades
Why: Different grades of avgas are dyed distinct colors (for example, blue and green for common grades) so the grade can be identified by sight and so contamination from mixing grades can be spotted, since a mixture produces an off or clear color. Color does not give a precise octane number, and dye is not an indicator of suspended water content.· FAA-H-8083-31 — Aircraft Fuel Systems (fuel grades and identification)
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What effect does water contamination have on the indication of a capacitance-type fuel-quantity system?
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Answer: It causes the contents to over-read
Why: A capacitance fuel-quantity probe reads quantity from the dielectric between its plates, and water has a much higher dielectric constant than fuel. Water settling in the tank raises the measured capacitance more than an equal volume of fuel would, so the gauge over-reads the true fuel contents.· FAA-H-8083-31 — Aircraft Fuel Systems
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When checking a capacitance-type fuel quantity indicating system, how is the test set connected to the tank probes?
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Answer: In parallel with the capacitance probes
Why: A capacitance fuel-quantity test set is connected in parallel with the tank probes so it can inject or simulate known capacitance values across the same circuit the indicator reads. Connecting in series or removing the probes would change the measured capacitance and prevent a valid calibration check of the system as installed.· FAA-H-8083-31 — Aircraft Fuel Systems
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The test set used to check a capacitance-type fuel quantity indicating system is built around a
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Answer: capacitance bridge
Why: A capacitance-type fuel quantity system measures fuel by the change in tank-probe capacitance, so its test set is built around a capacitance bridge that simulates and checks those capacitance values. Resistance or inductance decade boxes would not match the capacitive sensing principle of the gauging system.· FAA-H-8083-31 — Aircraft Fuel Systems
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In a capacitance-type fuel quantity system, the compensator unit installed at the bottom of the tank measures the:
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Answer: Dielectric constant (K value) of the fuel
Why: A capacitance fuel-gauging system depends on the dielectric constant (K value) of the fuel, which varies with fuel type and temperature. The compensator unit, always immersed at the bottom of the tank, measures this K value so the system can correct the main probes and read true fuel mass. It does not directly read quantity or specific gravity (FAA-H-8083-31, Aircraft Fuel Systems — capacitance fuel quantity indicating).· FAA-H-8083-31 — Aircraft Fuel Systems
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A float-type fuel quantity gauging system is best described as one that
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Answer: Cannot be adjusted in service
Why: A float-type fuel gauge mechanically follows the fuel surface through a float and arm, and its calibration is fixed by the geometry of the float, tank, and sender. There is no in-service empty or full adjustment to make, so the system cannot be adjusted; faults are corrected by replacing components.· FAA-H-8083-31 — Aircraft Fuel Systems
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In a capacitance-type fuel quantity system, changes in fuel temperature are compensated by
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Answer: placing a reference capacitor in parallel with the tank unit capacitance
Why: The dielectric constant of fuel changes with temperature, which would shift the capacitance reading. A compensating (reference) capacitor immersed in the fuel and connected in parallel with the tank-unit capacitance experiences the same change and cancels the temperature error. A simple series resistor or a potentiometer cannot track the dielectric variation.· FAA-H-8083-31 — Aircraft Fuel Systems
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A fuel quantity system that measures the specific gravity of the fuel displays the contents in
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Answer: pounds or kilograms.
Why: Measuring specific gravity allows the fuel-quantity system to convert volume into a true mass, so the contents are displayed as a weight in pounds or kilograms. Volume units such as gallons or liters would not account for the change in fuel density that the specific-gravity measurement corrects for.· FAA-H-8083-31 — Aircraft Fuel Systems
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In an integral fuel tank, the final layer of sealing applied over the assembled joints is called the
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Answer: brush coat.
Why: Integral fuel tank sealing is built up in stages, and the final sealing layer applied over the assembled joints is the brush coat, painted on to give a continuous fuel-tight skin. Interfay sealant goes between mating faces and fillet sealant fills the joint angles, so neither is the final coat.· FAA-H-8083-31 — Aircraft Fuel Systems
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What is the primary purpose of a fuel boost pump in an aircraft fuel system?
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Answer: To supply fuel under positive pressure to the engine-driven pump and prevent vapor lock
Why: Per FAA-H-8083-31, the boost (or auxiliary) pump provides positive fuel pressure to the engine-driven pump, prevents vapor lock by maintaining pressure on the fuel, supplies fuel for engine starting, and serves as a backup if the engine-driven pump fails.· FAA-H-8083-31 — Aircraft Fuel Systems
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Vapor lock in a fuel system is most likely to occur when
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Answer: fuel vaporizes in the lines or pump and the vapor pockets block normal fuel flow
Why: Per FAA-H-8083-31, vapor lock results when fuel vaporizes in the lines or pump and the vapor bubbles block fuel flow. It is promoted by high temperatures, low fuel pressure (such as at high altitude), and rapid fuel flow through restrictions. A boost pump maintaining positive pressure helps prevent it.· FAA-H-8083-31 — Aircraft Fuel Systems
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In a gravity-feed fuel system, fuel is delivered to the engine by
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Answer: the head of fuel created by tanks located above the carburetor
Why: Per FAA-H-8083-31, gravity-feed systems are used on high-wing aircraft where the fuel tanks are mounted above the carburetor. The weight (head) of the fuel provides the pressure to deliver fuel to the engine without a pump.· FAA-H-8083-31 — Aircraft Fuel Systems
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Why must fuel tanks be vented to the atmosphere?
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Answer: To maintain atmospheric pressure in the tank and allow for fuel expansion as fuel is used
Why: Per FAA-H-8083-31, tank vents maintain atmospheric pressure inside the tank as fuel is consumed. Without venting, a vacuum would form as fuel is drawn out, collapsing the tank or stopping fuel flow; venting also allows for thermal expansion and contraction of the fuel.· FAA-H-8083-31 — Aircraft Fuel Systems
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The fuel selector valve in a typical light aircraft is used to
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Answer: select the tank from which fuel is drawn or shut the fuel supply off
Why: Per FAA-H-8083-31, the fuel selector valve allows the pilot to select fuel from a particular tank, select 'both,' or shut the fuel supply off (OFF position). It controls which tank or tanks feed the engine.· FAA-H-8083-31 — Aircraft Fuel Systems
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A bladder-type fuel tank is best described as
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Answer: a reinforced flexible rubberized cell fitted into a cavity in the aircraft structure
Why: Per FAA-H-8083-31, a bladder (flexible) fuel cell is a reinforced rubberized bag fitted into a cavity in the structure. It is snapped or laced into place and relies on the surrounding structure for support, offering a degree of self-sealing and weight savings.· FAA-H-8083-31 — Aircraft Fuel Systems
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An integral fuel tank is one in which
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Answer: a portion of the aircraft structure itself is sealed to form the tank
Why: Per FAA-H-8083-31, an integral fuel tank uses a sealed-off portion of the aircraft structure (commonly called a 'wet wing') to hold fuel. The skin and structural members themselves form the tank walls, sealed at the seams and fasteners.· FAA-H-8083-31 — Aircraft Fuel Systems
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The primary purpose of a sump drain located at the lowest point of a fuel tank is to
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Answer: drain off water and sediment that settle at the lowest point of the tank
Why: Per FAA-H-8083-31, water is heavier than fuel and settles to the lowest point of the tank. The sump drain (quick-drain valve) at this low point allows accumulated water and sediment to be drained off during preflight inspection.· FAA-H-8083-31 — Aircraft Fuel Systems
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When checking a fuel tank sump for water contamination, water is identified because it
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Answer: settles to the bottom of the sample as a separate layer beneath the fuel
Why: Per FAA-H-8083-31, water is denser than aviation fuel and is immiscible with it, so it collects at the bottom of the sample. Water typically appears as clear globules or a separate layer beneath the colored fuel, and the fuel may appear cloudy when suspended water is present.· FAA-H-8083-31 — Aircraft Fuel Systems
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A fuel system crossfeed (cross-feed) arrangement on a multiengine aircraft is provided to
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Answer: allow either engine to draw fuel from tanks on either side of the aircraft
Why: Per FAA-H-8083-31, a crossfeed system allows fuel from a tank on one side of the aircraft to be supplied to an engine on the opposite side. This helps maintain lateral balance and allows an engine to draw from any available tank if one engine or fuel supply is lost.· FAA-H-8083-31 — Aircraft Fuel Systems
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What is the function of a fuel pressure relief valve on a positive-displacement, engine-driven fuel pump?
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Answer: It bypasses excess fuel to regulate the pump's output pressure
Why: Per FAA-H-8083-31, an engine-driven vane (positive-displacement) pump produces more pressure and volume than the engine needs. A built-in relief valve bypasses excess fuel back to the pump inlet to regulate the output to the desired pressure.· FAA-H-8083-31 — Aircraft Fuel Systems
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Why is an electric boost pump frequently a centrifugal type rather than a positive-displacement type?
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Answer: Fuel can flow through a centrifugal pump even when it is not operating
Why: Per FAA-H-8083-31, the centrifugal boost pump is non-positive-displacement, so it does not need a separate relief valve and fuel can flow through it (bypass) even when it is not operating. This allows the engine-driven pump or gravity to draw fuel through an inactive boost pump.· FAA-H-8083-31 — Aircraft Fuel Systems
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The main fuel strainer (gascolator) in a typical reciprocating-engine fuel system is normally located
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Answer: at a low point in the system between the tank and the fuel metering device
Why: Per FAA-H-8083-31, the main strainer (gascolator) is placed at the lowest point in the fuel system, between the tank and the carburetor/metering device, so that water and sediment can collect in its bowl and be drained, protecting the engine fuel metering components.· FAA-H-8083-31 — Aircraft Fuel Systems
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Which fuel-quantity indicating system measures the actual mass (weight) of fuel rather than its volume?
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Answer: The capacitance (dielectric) type system
Why: Per FAA-H-8083-31, the capacitance-type (dielectric) fuel-quantity system uses tank units that act as capacitors. Because fuel and air have different dielectric constants, the system can be calibrated to read fuel mass (pounds), which is more accurate than volume because fuel density changes with temperature.· FAA-H-8083-31 — Aircraft Fuel Systems
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In a capacitance-type fuel-quantity indicating system, the tank units function as
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Answer: capacitors whose capacitance varies with the level of fuel between their plates
Why: Per FAA-H-8083-31, the tank units (probes) are capacitors whose dielectric is the fuel and air between their plates. As fuel level changes, the dielectric changes, altering capacitance. The bridge circuit converts this change into a fuel-quantity indication.· FAA-H-8083-31 — Aircraft Fuel Systems
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A fuel flowmeter in a fuel-injected reciprocating engine system actually indicates fuel flow by sensing
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Answer: the fuel pressure at or across the injector nozzles, calibrated as flow
Why: Per FAA-H-8083-31, in many fuel-injected reciprocating-engine installations the 'fuel flow' gauge is actually a pressure gauge that measures the pressure drop across the injector nozzles. Because flow and that pressure are related, the gauge is calibrated in gallons per hour or fuel flow.· FAA-H-8083-31 — Aircraft Fuel Systems
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Why is microbial growth a concern in aircraft fuel tanks, particularly with turbine fuels?
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Answer: Microbes live at the fuel-water interface and form slime that clogs filters and corrodes tanks
Why: Per FAA-H-8083-31, microbial contaminants (fungi and bacteria) live at the fuel-water interface where free water is present. They form a slime that can clog filters and fuel system components and can cause corrosion of tank structure. Keeping water drained off helps control growth.· FAA-H-8083-31 — Aircraft Fuel Systems
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During fueling operations, why must the aircraft and the fueling source be electrically bonded together?
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Answer: To equalize electrical potential and prevent a static spark from igniting fuel vapors
Why: Per FAA-H-8083-31, fuel flowing through hoses and nozzles generates a static electrical charge. Bonding the aircraft to the fuel source (and grounding) equalizes the electrical potential so that a static spark cannot occur at the fuel opening and ignite fuel vapors.· FAA-H-8083-31 — Aircraft Fuel Systems
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A pressure-fueling (single-point) system on a large aircraft offers the advantage of
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Answer: fueling all tanks rapidly from one connection while reducing contamination and static hazards
Why: Per FAA-H-8083-31, single-point pressure fueling fuels all tanks from one ground connection under pressure. It reduces fueling time, minimizes the chance of fuel contamination and static buildup associated with open over-wing fueling, and reduces the hazard of personnel working on top of the wing.· FAA-H-8083-31 — Aircraft Fuel Systems
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The purpose of fuel dump (jettison) valves installed on some large aircraft is to
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Answer: discharge fuel overboard in flight to reduce aircraft weight to the maximum landing weight
Why: Per FAA-H-8083-31, fuel jettison (dump) systems allow fuel to be discharged overboard in flight to reduce the aircraft's weight quickly to or below the maximum landing weight, for example after a takeoff that requires an emergency return.· FAA-H-8083-31 — Aircraft Fuel Systems
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Before repairing a fuel tank that has contained fuel, the most important safety step is to
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Answer: purge the tank of all fuel vapors so it is free of combustible vapor
Why: Per FAA-H-8083-31, a fuel tank must be purged of all fuel vapors before any repair involving heat or sparks. Even an empty tank holds explosive vapors; purging and ensuring the tank is free of combustible vapors prevents an explosion during welding or other hot work.· FAA-H-8083-31 — Aircraft Fuel Systems
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Aviation gasoline (avgas) grades are identified primarily by
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Answer: their octane/performance number indicating antiknock characteristics
Why: Per FAA-H-8083-31, avgas grades (such as 80, 100, and 100LL) are designated by their octane or performance numbers, which indicate the fuel's antiknock (detonation-resistance) characteristics. Each grade is also dyed a distinctive color for identification.· FAA-H-8083-31 — Aircraft Fuel Systems
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If the wrong grade of fuel must be identified after a tank is filled, one reliable indicator is that each avgas grade is
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Answer: dyed a distinctive color associated with that grade
Why: Per FAA-H-8083-31, aviation gasoline grades are dyed distinctive colors (for example, 80 is red, 100LL is blue, 100 is green) so they can be visually distinguished. Turbine fuel (Jet A) is colorless to straw-colored, which also helps detect contamination or misfueling.· FAA-H-8083-31 — Aircraft Fuel Systems
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Why is it hazardous to service a turbine-powered aircraft with aviation gasoline when turbine (jet) fuel is required?
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Answer: The fuels have different combustion and lubricity properties that can cause engine damage or failure
Why: Per FAA-H-8083-31, misfueling a turbine engine with avgas (or fueling a reciprocating engine with jet fuel) can cause engine damage and failure because the fuels have different combustion, lubricity, and volatility characteristics. Proper fuel grade and correct nozzles/placards are critical to prevent misfueling.· FAA-H-8083-31 — Aircraft Fuel Systems
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Fuel lines in an aircraft fuel system that are subject to vibration are most commonly fabricated from
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Answer: flexible hose, to absorb vibration and relative movement between components
Why: Per FAA-H-8083-31, flexible hose is used where there is relative movement or vibration between connected components (for example, between airframe-mounted lines and the engine), while rigid metal tubing is used in fixed areas of the airframe. Flexible hose absorbs vibration and accommodates engine movement.· FAA-H-8083-31 — Aircraft Fuel Systems
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A fuel heater is installed in some turbine-engine fuel systems primarily to
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Answer: prevent ice crystals in the fuel from blocking the fuel filter
Why: Per FAA-H-8083-31, a fuel heater warms the fuel before it reaches the fuel filter to prevent ice crystals (formed from dissolved/free water at low temperatures) from accumulating and blocking the filter. It protects the filter from icing rather than improving combustion.· FAA-H-8083-31 — Aircraft Fuel Systems
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What does a fuel filter bypass (differential pressure) warning indicate?
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Answer: The filter element is becoming clogged and the bypass valve is about to open
Why: Per FAA-H-8083-31, when a fuel filter becomes clogged, the differential pressure across it increases. A bypass valve opens to allow unfiltered fuel to continue to the engine, and an impending-bypass (differential-pressure) indicator warns that the filter element is dirty and needs servicing.· FAA-H-8083-31 — Aircraft Fuel Systems
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On a low-wing aircraft equipped with a fuel selector that has 'LEFT,' 'RIGHT,' and 'OFF' positions but no 'BOTH' position, the pilot manages fuel by
Show the answer and explanation
Answer: drawing from one tank at a time and switching periodically to keep the load balanced
Why: Per FAA-H-8083-31, low-wing aircraft typically use pump-fed systems and a selector without a BOTH position because fuel cannot reliably gravity-feed and unported feed from both could be uneven. The pilot selects one tank at a time and switches periodically to keep the tanks balanced.· FAA-H-8083-31 — Aircraft Fuel Systems
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The areas that share the most ground with AM.II.J — study them alongside it.
- Engine Fuel and Fuel Metering Systems (AM.III.I)
- Fluid Lines and Fittings (AM.I.D)
- Ground Operations and Servicing (AM.I.F)
Frequently asked questions
- What is the purpose of a fuel tank sump and drain valve?
- The sump is the lowest point of the tank, and water and sediment collect there because water is denser than fuel. The drain valve lets you take a sample into a clear container and check for a separate water layer, cloudiness or debris, and it removes the contamination you find. That is why sump draining appears on both preflight checks and scheduled inspection items.
- What causes vapor lock in an aircraft fuel system?
- Heat, low pressure and a fuel that vaporizes easily. When fuel boils inside the lines, the vapor pockets block liquid flow and the engine loses fuel pressure or stops. Hot restarts, climbs to altitude and lines routed near hot engine parts are the usual settings. Switching on the electric boost pump raises line pressure and pushes the vapor back toward the tank.
- What color is 100LL aviation gasoline?
- 100LL is dyed blue and grade 100 is dyed green. The dye identifies the grade so a mechanic or pilot can confirm the correct fuel went into the tank and can spot mixed or contaminated fuel in a drained sample. Jet fuel is not dyed and appears clear to light straw, so a colorless sample drawn from an avgas tank deserves a second look.
- How does a gravity-feed fuel system work without a pump?
- The tanks are mounted above the engine, so the head pressure of the fuel column moves fuel to the carburetor by gravity alone. High-wing light airplanes commonly use this layout. The system still needs vented tanks, a selector valve, a strainer and sump drains, and certification rules set a minimum flow rate it must deliver, but no boost or engine-driven pump is required for normal operation.
- Are fuel systems on the Airframe or Powerplant test?
- Aircraft fuel systems, meaning tanks, pumps, valves, lines and quantity indicating, is an Airframe subject area coded AM.II.J, so it appears on the Airframe written test. Engine fuel metering, carburetors and fuel injection sit on the Powerplant side. The rough dividing line is the firewall: everything up to the engine's fuel inlet is airframe territory.
All 40 ACS areas
General
- Fundamentals of Electricity and Electronics
- Aircraft Drawings
- Weight and Balance
- Fluid Lines and Fittings
- Aircraft Materials, Hardware, and Processes
- Ground Operations and Servicing
- Cleaning and Corrosion Control
- Mathematics
- Regulations, Maintenance Forms, Records, and Publications
- Physics for Aviation
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- Human Factors
Airframe
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- Airframe Inspection
- Landing Gear Systems
- Hydraulic and Pneumatic Systems
- Environmental Systems
- Aircraft Instrument Systems
- Communications, Light Signals, and Runway Lighting Systems
- Aircraft Fuel Systems
- Aircraft Electrical Systems
- Ice and Rain Control Systems
- Airframe Fire Protection Systems
- Rotorcraft Fundamentals
- Water and Waste Systems
Powerplant
- Reciprocating Engines
- Turbine Engines
- Engine Inspection
- Engine Instrument Systems
- Engine Fire Protection Systems
- Engine Electrical Systems
- Engine Lubrication Systems
- Ignition and Starting Systems
- Engine Fuel and Fuel Metering Systems
- Reciprocating Engine Induction and Cooling Systems
- Turbine Engine Air Systems
- Engine Exhaust and Reverser Systems
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