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The real Aviation Mechanic - Powerplant written test has 100 multiple-choice questions (3 options each), a 2-hour time limit, and requires 70% to pass. Questions are drawn across 13 knowledge areas per the FAA-S-ACS-1 blueprint; this bank mirrors those areas and weights.
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The full Aviation Mechanic - Powerplant bank contains 577 questions with explanations. The free sample gives you roughly two exams' worth per knowledge area.
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A selection of free questions with answers and explanations. Use the interactive modules above for timed, scored drills.
A wet-sump lubrication system stores the engine oil where?
Why: In a wet-sump system the oil supply is carried in the engine's own crankcase sump; most horizontally opposed engines use wet-sump lubrication. FAA-H-8083-32B ch.6.
During a turbine engine air-system inspection, cooling-air ducting and baffle seals are checked for what?
Why: Cooling ducting (rigid/flexible) and baffle seals are inspected for cracks, leaks, security, and deterioration, because any leakage reduces the cooling airflow reaching the components. FAA-H-8083-32B ch.1.
During start, a starter-generator draws heavy current from the battery/ground power to do what, then reverses role how?
Why: As a starter, the starter-generator draws heavy current to crank the engine; once the engine is self-sustaining, its circuitry reconfigures it as a generator that supplies the bus and recharges the battery. FAA-H-8083-32B ch.5.
Why is carburetor ice possible even on a warm, humid day?
Why: Because fuel evaporation absorbs heat and the venturi drops the pressure/temperature, the induction air can cool below freezing even when the outside air is warm (e.g., 70-100 F) and humid — a common cause of carburetor ice. FAA-H-8083-32B ch.3.
A turboprop air inlet presents an extra design problem compared with a turbojet because of what?
Why: A turboprop inlet must be designed around the propeller drive shaft, hub, and spinner; a ducted arrangement is generally the best design for airflow and aerodynamic characteristics. FAA-H-8083-32B ch.3.
A DC generator's output voltage is controlled by adjusting what?
Why: A DC generator's output voltage is controlled by varying the field current; the voltage regulator increases or decreases field current to keep the output constant as speed and load change. FAA-H-8083-32B ch.4.
An indication that a turbine engine anti-ice (bleed air) system is functioning may include what?
Why: Selecting engine anti-ice bleeds warm air, which slightly changes engine parameters (a small EGT rise and thrust change) — a normal indication used to confirm the anti-ice valves have opened. FAA-H-8083-32B ch.3.
During cruise, why are cowl flaps normally closed?
Why: At cruise the higher airspeed provides ample cooling airflow, so the cowl flaps are closed to reduce the aerodynamic drag (and improve efficiency); they are opened for climb/ground operation where more cooling is needed. FAA-H-8083-32B ch.3.
Turbine engine oils are typically what type?
Why: Turbine engines use synthetic oils formulated to withstand the high operating temperatures and to resist thermal breakdown; they are not interchangeable with reciprocating-engine mineral/AD oils. FAA-H-8083-32B ch.6.
Approximately half of all muffler and heat exchanger failures can be traced to what?
Why: About half of muffler/heat-exchanger failures are cracks or ruptures in the heat-exchanger surface (usually the outer wall) that supplies cabin and carburetor heat, allowing exhaust gas into those systems. FAA-H-8083-32B ch.3.
During reciprocating engine ground run-up, a magneto check that shows an excessive rpm drop on one magneto indicates what?
Why: During the mag check, switching to one magneto normally causes a small rpm drop; an excessive drop (or no drop) indicates an ignition fault such as a fouled spark plug, a defective lead, or a magneto problem on that side. FAA-H-8083-32B ch.1.
On a twin-spool turbofan, what do the terms N1 and N2 refer to?
Why: N1 is the rotational speed of the low-pressure spool (fan/LP compressor and LP turbine) and N2 is the speed of the high-pressure spool (HP compressor and HP turbine), each expressed as a percent of maximum rpm. FAA-H-8083-32B ch.1.
Turbine inlet temperature (TIT) is monitored because it reflects what?
Why: TIT (or ITT) measures the gas temperature at/near the turbine inlet, the hottest practical measuring point; it is monitored closely because the turbine operates near its material temperature limit and overtemperature causes rapid damage. FAA-H-8083-32B ch.10.
When inspecting engine mounts, the technician looks primarily for what?
Why: Engine mount inspection checks the mount structure and hardware for cracks, distortion, corrosion, and security, and checks the vibration isolators (shock mounts) for deterioration, since a failed mount is a serious hazard. FAA-H-8083-32B ch.8.
What is the function of a voltage regulator in an engine-driven electrical system?
Why: The voltage regulator holds the system voltage constant by adjusting the field current of the generator or alternator as engine speed and electrical load vary. FAA-H-8083-32B ch.4.
After maintenance on an engine fire detection/extinguishing system, a key final step is to do what?
Why: A functional (built-in) test after fire-system maintenance confirms the detection loop and warning circuit operate and, for extinguishing systems, that squib firing-circuit continuity is correct, without actually discharging the bottle. FAA-H-8083-32B ch.9.
Turbine engine internal air cooling directs compressor air to cool which hot-section parts?
Why: Internal cooling air (from the compressor) is directed over the hottest parts — turbine nozzle guide vanes, turbine blades, and disks — to keep their temperatures within limits despite the high gas temperatures. FAA-H-8083-32B ch.1.
Inspection of aluminum propeller blades by dye-penetrant inspection is accomplished to detect
Why: Dye-penetrant inspection of aluminum propeller blades detects fatigue-failure cracks per FAA-H-8083-32B ch.7.
The firing order of a nine-cylinder single-row radial engine is what?
Why: The firing order of a nine-cylinder radial engine is 1-3-5-7-9-2-4-6-8, arranged so the firing impulses are evenly distributed around the crankcase. FAA-H-8083-32B ch.1.
Who establishes the recommended operating time between overhauls (TBO) of a turbine engine used in general aviation?
Why: Recommended TBO is specified by the engine manufacturer per FAA-H-8083-32B ch.1.
What is the purpose of the de-aerator (air separator) in a turbine engine oil tank?
Why: The scavenge pumps return oil mixed with air; a de-aerator in the tank separates this air out so that solid, air-free oil is supplied to the pressure pump, ensuring proper lubrication and accurate quantity. FAA-H-8083-32B ch.6.
An engine that has been submerged (e.g., in a flood or ditching) requires what?
Why: A submerged (flood/immersion) engine requires a special inspection and usually a teardown/overhaul because water and contaminants enter the engine and cause corrosion and bearing/component damage. FAA-H-8083-32B ch.8.
A progressive inspection program for an engine/aircraft is authorized under which regulation?
Why: A progressive inspection may be used under 14 CFR 91.409(d) as an alternative to the annual, provided the complete aircraft/engine is inspected within each 12 calendar months. 14 CFR 91.409(d).
A 'shower of sparks' starting system uses what to aid starting?
Why: The shower of sparks system uses an induction vibrator to feed a rapid series of sparks to a retard breaker/points during starting, giving a 'shower' of retarded sparks that improves starting and prevents kickback. FAA-H-8083-32B ch.4.
An engine fuel system inspection includes checking for what?
Why: Fuel system inspection covers leaks, the security and condition of lines, hoses, and fittings, filter/strainer condition (water/sediment), and correct operation of the fuel pump and metering (carburetor/injection/FCU) unit. FAA-H-8083-32B ch.2.
A starter-generator combines which functions on a turbine engine?
Why: A starter-generator is one unit that serves as the starter to crank the engine and then as the generator once running, saving the weight of separate components; it is common on turbine engines. FAA-H-8083-32B ch.5.
On a turbosupercharged engine, the exhaust system operates under what condition compared with a normally aspirated one?
Why: With a turbocharger/turbosupercharger the exhaust system runs under greatly increased pressure and temperature; extra precautions in care and maintenance are required, especially at high-altitude operation. FAA-H-8083-32B ch.3.
A starter-generator combines which two functions, and where is it common?
Why: A starter-generator serves as the starter to crank the engine, then functions as the generator once the engine is running; combining the two units saves weight and is common on turbine engines. FAA-H-8083-32B ch.5.
The scope and detail of items for an engine annual/100-hour inspection are found where?
Why: The scope and detail of items to include in an annual or 100-hour inspection (including engine items) are listed in 14 CFR part 43, Appendix D. 14 CFR part 43 App D.
A term commonly used when two or more electrical terminals are installed on a single lug of a terminal strip is
Why: Installing two or more terminals on a single lug of a terminal strip is commonly called stacking per FAA electrical references.