FAA Aviation Mechanic Powerplant (AMP) practice questions
335 free questions with answers and explanations.
- 51.A student mechanic removes a spark plug from a reciprocating engine cylinder and notices the electrodes are coated with a heavy black, dry, fluffy deposit. What condition does this indicate?Engine Inspection
- 52.During a ground run, a constant-speed propeller governor's flyweights move outward due to increasing engine RPM above the selected setting. What action does this cause?Propellers
- 53.A mechanic finds a small chordwise nick on the leading edge of an aluminum propeller blade during a 100-hour inspection. What is the correct initial course of action?Propellers
- 54.During external timing of a magneto to a reciprocating engine, the technician positions the crankshaft at the manufacturer's specified number of degrees before top dead center on the compression stroke of the No. 1 cylinder. What must occur at exactly this crankshaft position for the magneto to be correctly timed?Ignition and Starting Systems
- 55.A technician connects an ignition analyzer (oscilloscope) to the ignition harness of a reciprocating engine to troubleshoot rough running. One cylinder's firing pattern shows a noticeably higher peak firing voltage (kV) than the other cylinders. What condition does this most likely indicate?Ignition and Starting Systems
- 56.During a borescope inspection of a turbine engine, a technician observes localized hot spots and small burn-through areas on the combustion liner, concentrated near one fuel nozzle location. What is the most likely cause of this damage?Engine Inspection
- 57.A technician replaces the ignition harness on a reciprocating engine. What is the primary purpose of the metal braided shielding surrounding each ignition lead?Ignition and Starting Systems
- 58.A technician removes a main bearing shell from a reciprocating engine crankshaft and notices bright, copper-colored streaks showing through the bearing's babbitt overlay surface. What does this indicate?Engine Inspection
- 59.A technician is about to remove a spark plug from a radial engine cylinder for inspection. The ignition switch is confirmed OFF. What additional precaution should be taken before touching the propeller or plug leads?Ignition and Starting Systems
- 60.A technician is checking valve clearance on a radial engine cylinder equipped with solid lifters (no hydraulic units). To obtain an accurate feeler gauge reading, the piston in that cylinder should be positioned at:Engine Inspection
- 61.A modern turbofan engine is equipped with a Full Authority Digital Engine Control (FADEC) system. A technician explains this system to a new hire. Which statement best describes FADEC?Turbine Engines
- 62.A mechanic is troubleshooting a float carburetor on a reciprocating engine that hesitates and momentarily loses power when the throttle is rapidly advanced from idle. Which component is most likely malfunctioning?Fuel, Induction and Lubrication
- 63.An aircraft's pneumatic system uses compressor bleed air tapped from the turbine engine for several purposes. Which of the following is NOT a typical use of engine bleed air?Turbine Engines
- 64.During a ground run, a mechanic observes that engine oil pressure remains excessively high even after the engine reaches normal operating temperature. The mechanic suspects the oil pressure relief valve is stuck. In which position would this cause the observed symptom?Fuel, Induction and Lubrication
- 65.During a turbine engine start, the engine successfully lights off but the RPM stagnates at a value well below normal idle speed and fails to continue accelerating. Which of the following is the most likely cause of this condition?Ignition and Starting Systems
- 66.A mechanic removes a turbine engine igniter plug and notices it does not fire across a fixed narrow gap like an automotive spark plug. Instead, it stores electrical energy and releases it in an intense spark across a resistive surface. Which igniter type is this, and why is it used?Turbine Engines
- 67.A turbine engine's exhaust gas temperature (EGT) indicating system uses several thermocouple probes mounted around the exhaust duct and wired together in parallel to a single indicator. What is the main purpose of connecting the probes this way?Turbine Engines
- 68.On a turbine engine, the accessory gearbox provides mounting pads for components such as the fuel pump, oil pump, and generator. Which component transmits rotational power from the engine's main shaft to drive the accessory gearbox?Turbine Engines
- 69.A turbine engine's lubrication system is designed with scavenge pump capacity significantly greater than pressure pump capacity. Why is this design necessary?Turbine Engines
- 70.A mechanic studies the exhaust section of a turbojet engine located immediately aft of the last turbine stage. What is the primary function of the exhaust cone (tailcone) in this location?Turbine Engines
- 71.What is the primary purpose of valve overlap in a reciprocating aircraft engine?Reciprocating Engines
- 72.During a maintenance ground run, a turbine engine briefly exceeds its maximum N2 rotor speed limit. Inspection criteria require special attention to the turbine disc because sustained excessive centrifugal and thermal stress can cause which progressive failure mode?Turbine Engines
- 73.An inspector is checking a propeller for track and balance. What is the primary difference between these two checks?Propellers
- 74.A mechanic removes a compressor rotor blade from its disc slot and notices the blade root is machined into a wedge-shaped, serrated profile that matches a corresponding slot in the disc rim. What type of blade attachment is this?Turbine Engines
- 75.A turbine engine's main shaft is supported by ball bearings at one location and roller bearings at another. What is the primary reason for using these two different bearing types along the same shaft?Turbine Engines
- 76.A pilot reviews a carburetor icing probability chart during preflight planning. Under which condition can carburetor icing occur even though the outside air temperature (OAT) is as high as 70°F (21°C)?Reciprocating Engines
- 77.A technician inspecting a fixed-pitch aluminum propeller finds a small nick approximately 1/16 inch deep on the leading edge, 8 inches from the tip. Per typical manufacturer guidance, what is the correct next step?Engine Inspection
- 78.During landing rollout, a turboprop pilot moves the power lever below the flight idle gate into the beta range. What occurs during operation in this range?Turbine Engines
- 79.A technician discovers that a reciprocating engine's crankcase breather line is completely blocked with ice during a flight in cold, moist conditions. What is the most likely consequence of this blockage?Reciprocating Engines
- 80.During an engine ground run, a mechanic notices that fuel flow to a fuel-injected engine drops and the engine surges intermittently on a hot day shortly after a fast taxi and shutdown/restart cycle. Vapor is suspected to have formed in the fuel line between the tank and the fuel pump. Which factor is the most likely primary cause of this vapor lock?Fuel, Induction and Lubrication
- 81.An aircraft engine is equipped with a single dual magneto (one housing containing two independent sets of breaker points, coils, and distributors) rather than two separate magnetos. What is the primary advantage this design provides?Ignition and Starting Systems
- 82.A technician is inspecting a wet-type piston pin (piston pin bushing) removed from a reciprocating engine cylinder assembly. The pin is free to rotate in both the piston bosses and the connecting rod bushing. This describes which type of piston pin retention?Reciprocating Engines
- 83.A pilot applies carburetor heat to clear suspected carburetor icing during cruise flight in a normally aspirated reciprocating engine. What immediate effect on engine operation should the pilot expect from applying carburetor heat, assuming no ice is present?Reciprocating Engines
- 84.A technician is setting the electrode gap on a new spark plug for a reciprocating engine cylinder to a specification of 0.016 inch. Which tool provides the most accurate gap measurement for this round-electrode plug?Ignition and Starting Systems
- 85.During an engine ground run, a technician observes oil pressure that remains abnormally high at all RPM settings, even though oil temperature is within the normal operating range. Which malfunction is most likely responsible?Reciprocating Engines
- 86.After installing a new fuel control unit on a turbine engine, a technician performs an engine trim run per the maintenance manual, checking engine speed against EPR or EGT at a specified reference OAT and barometric pressure. What is the primary purpose of this engine trim procedure?Turbine Engines
- 87.A turbojet engine has a mass airflow rate of 200 lbm/sec. The inlet (freestream) velocity is 400 ft/sec and the exhaust jet velocity is 1,200 ft/sec. Using F = (W/g)(Ve − Vo), what is the approximate net thrust produced (neglecting pressure thrust)?Turbine Engines
- 88.An engine equipped with a full-flow oil filter experiences a partially clogged filter element during operation. What is the purpose of the bypass (relief) valve built into the oil filter assembly?Reciprocating Engines
- 89.A mechanic checks the oil level on a wet-sump reciprocating engine immediately after engine shutdown and reads 4 quarts, well below the 6 quarts specified in the AFM. After waiting 10 minutes and rechecking, the dipstick reads 6 quarts. What most likely explains this difference?Fuel, Induction and Lubrication
- 90.During a scheduled inspection program, a technician submits an engine oil sample for spectrometric oil analysis (SOAP). The most recent report shows a sharp increase in iron and chromium content compared to previous samples, while other elements remain stable. This trend most likely indicates:Reciprocating Engines
- 91.A mechanic is investigating engine damage after a pilot inadvertently used a lower octane fuel than specified for a high-compression reciprocating engine. Which condition most likely caused the damage?Fuel, Induction and Lubrication
- 92.A mechanic measures crankshaft flange runout using a dial indicator while slowly rotating the crankshaft, obtaining a total indicator reading (TIR) of 0.006 inch. The manufacturer's overhaul manual specifies a maximum allowable flange runout of 0.005 inch TIR. What action should the mechanic take?Engine Inspection
- 93.A twin-engine aircraft has a hydromatic propeller system. The pilot activates the feather button, but engine oil pressure alone may be insufficient to fully feather the blades quickly. What component ensures rapid feathering under this condition?Propellers
- 94.During a ground run following propeller governor reinstallation, a mechanic notices that the engine RPM exceeds the maximum allowable limit even though the cockpit propeller control is at the full increase-RPM position and the governor is functioning normally in flight-range control. What is the most likely cause?Engine Inspection
- 95.A mechanic is troubleshooting a light aircraft's fuel quantity indicating system that uses a float-type sender. As the fuel level changes, the float arm moves a wiper across a resistive element inside the sender. What does this changing resistance directly control?Fuel, Induction and Lubrication
- 96.A technician is performing an idle mixture check on a float-type carburetor per the manufacturer's maintenance manual. Upon slowly retarding the mixture control toward idle cutoff at idle RPM, the engine RPM briefly rises 25 to 50 RPM before dying. What does this rise in RPM indicate?Reciprocating Engines
- 97.A ground crew connects an external air cart to start a turbine engine. Which statement best describes how a pneumatic (air turbine) starter functions?Turbine Engines
- 98.A mechanic explains propeller theory to a student regarding the forces acting on a rotating blade. The aerodynamic twisting moment created by the airflow's center of pressure acting ahead of the blade's pitch-change axis tends to move the blade toward which condition?Propellers
- 99.A mechanic is preparing to service a piston-engine aircraft placarded for 100LL fuel. What does the number '100' in the fuel designation '100LL' represent?Fuel, Induction and Lubrication
- 100.A mechanic is calculating the rotational tip speed of a propeller with a diameter of 6 feet turning at 2,500 RPM to evaluate proximity to sonic speeds. What is the approximate rotational tip speed in miles per hour?Propellers