FAA Aviation Mechanic Powerplant (AMP) practice questions
335 free questions with answers and explanations.
- 101.A line technician is servicing a piston-powered aircraft and must select the correct fuel. The aircraft fuel filler placard specifies 100LL. What color should this fuel be, and what does this help prevent?Fuel, Induction and Lubrication
- 102.A technician inspecting a high-tension magneto notices excessive wear at the distributor rotor finger and distributor block electrodes, increasing the air gap between them. What is the most significant operational effect of this wear at high altitude?Ignition and Starting Systems
- 103.A technician is selecting fuel for a reciprocating engine placarded for 100LL aviation gasoline. What does the octane (performance) rating of the fuel primarily indicate?Reciprocating Engines
- 104.A technician is asked to explain the purpose of a synchrophaser system installed on a multi-engine turboprop aircraft. What does this system primarily accomplish?Propellers
- 105.A turbine engine's fuel filter is equipped with a differential pressure indicator that pops out when the pressure drop across the filter exceeds 5 psi. During an inspection, the technician measures 42 psi at the filter inlet and 35 psi at the filter outlet, and the indicator has popped. What is the correct interpretation and action?Engine Inspection
- 106.A mechanic is troubleshooting a continuous-flow fuel injection system and needs to explain the purpose of the flow divider (distributor valve) to an apprentice. What function does this component perform?Fuel, Induction and Lubrication
- 107.A technician inspects an engine's oil pressure relief valve after a report of low oil pressure at high RPM but normal pressure at idle. Disassembly reveals the relief valve spring has weakened and lost tension. What effect would this have on oil pressure?Engine Inspection
- 108.A mechanic explains proper mixture leaning procedure to a pilot using the exhaust gas temperature (EGT) gauge for best power cruise operation. Which mixture setting corresponds to best power?Fuel, Induction and Lubrication
- 109.During a 100-hour inspection, a technician finds several broken and bent cooling fins on a cylinder near the intake port, with no other visible cylinder damage. What is the primary airworthiness concern with this finding?Reciprocating Engines
- 110.A technician is preparing to start a reciprocating engine in extremely cold weather and preheats the engine before attempting a start. Beyond oil viscosity concerns, why is preheating important for successfully starting the ignition and engine?Ignition and Starting Systems
- 111.A technician troubleshooting a magneto finds severe arcing and pitting at the breaker points, along with a weak spark at the plugs. Which component, when defective, is most likely responsible for this condition?Ignition and Starting Systems
- 112.A mechanic is adjusting valve clearance on a reciprocating engine equipped with solid (mechanical) lifters. If the clearance is set too tight (less than specified), what is the most likely result?Reciprocating Engines
- 113.A mechanic is performing internal timing on a magneto and rotates the drive shaft to the E-gap position before closing the breaker points. What does the E-gap position represent?Engine Inspection
- 114.Why do turbine engine ignition systems typically use high-energy capacitor-discharge (CD) exciter units rather than the magneto-type ignition systems used on reciprocating engines?Turbine Engines
- 115.A turbojet engine burns fuel at a rate of 8,000 lb/hr while producing 4,000 lb of net thrust. What is the engine's thrust specific fuel consumption (TSFC)?Turbine Engines
- 116.A turboprop pilot moves the power lever into the Beta range during landing rollout. What does operating in this range allow?Propellers
- 117.An engine's oil consumption records show that 3 quarts of oil were added over a 25-hour flight period. The manufacturer's service limit for acceptable oil consumption is 1 quart per 10 hours. Based on this trend, is the engine's oil consumption within limits?Engine Inspection
- 118.A mechanic is explaining the difference between a full-flow and a partial-flow (bypass) oil filtration system to an apprentice. Which statement correctly describes this difference?Fuel, Induction and Lubrication
- 119.A technician performs a differential compression check on a cylinder using 80 psi of input air pressure. Per general industry guidance, what reading would typically prompt further investigation into the cylinder's condition?Reciprocating Engines
- 120.A turbocharged reciprocating engine uses a wastegate to control manifold pressure. What is the primary function of the wastegate?Reciprocating Engines
- 121.A turboprop engine's design incorporates a 'free turbine' (power turbine) arrangement. Which statement best describes this configuration?Turbine Engines
- 122.A mechanic is selecting a replacement propeller for a high-horsepower engine installed on an aircraft with limited ground clearance. Why might a four-blade propeller be preferred over a two-blade propeller that absorbs the same engine power?Propellers
- 123.A technician measures a piston skirt and finds its diameter slightly greater when measured perpendicular to the piston pin than when measured parallel to the pin axis (a cam-ground or elliptical shape). What is the purpose of this design?Reciprocating Engines
- 124.An aircraft's operating limitations placard lists a restricted RPM range for continuous operation. Why is this range prohibited for sustained ground and flight operation?Propellers
- 125.During an oil system inspection, a technician finds that the full-flow oil filter's bypass valve has been opening frequently based on the maintenance log. What condition would most likely cause this?Fuel, Induction and Lubrication
- 126.A mechanic is inspecting a dry-sump reciprocating engine oil system and needs to explain the primary advantage of this design compared to a wet-sump system to a trainee. What is the primary advantage?Fuel, Induction and Lubrication
- 127.A mechanic is functionally checking a resistance-bulb type cylinder head temperature (CHT) probe removed from a reciprocating engine. Using an ohmmeter, the mechanic measures the probe's resistance at a known ambient temperature and compares it to the manufacturer's resistance-versus-temperature chart. What does this check verify?Engine Inspection
- 128.A high-bypass turbofan engine's inlet duct and fan cowl are lined with perforated honeycomb acoustic panels. What is the primary purpose of these panels?Turbine Engines
- 129.A mechanic is troubleshooting a continuous-flow fuel injection system on a horizontally opposed engine. Fuel is metered by the fuel control unit based on airflow and then distributed to each cylinder through a component mounted at the top of the engine that divides the flow equally to all injector lines. What is this component called?Reciprocating Engines
- 130.A turbine engine ignition exciter unit is being tested. What type of ignition system does this unit typically represent, and why is it required for turbine engines?Ignition and Starting Systems
- 131.A turbofan engine's high-pressure compressor incorporates variable stator vanes (VSVs) in its forward stages. The primary purpose of these vanes is toTurbine Engines
- 132.Which type of gas turbine engine uses a large-diameter fan at the front of the engine to bypass a large portion of incoming air around the engine core, with most of the thrust produced by the bypassed air rather than the core exhaust gases?Turbine Engines
- 133.A propeller shop technician places a removed propeller on knife-edges to check for balance before installation. This test primarily checks for what type of imbalance?Propellers
- 134.A turbine blade is manufactured with small holes along its leading edge and surface through which cooling air is discharged to create a protective layer of cooler air over the blade surface. This describes which turbine blade cooling method?Turbine Engines
- 135.A mechanic explains to a pilot that the chemically correct (stoichiometric) fuel/air ratio for aviation gasoline is approximately 15:1 by weight, but that engines are typically operated at a richer ratio of about 12:1 for takeoff and climb power. What is the primary reason for enriching the mixture beyond stoichiometric for best power operation?Fuel, Induction and Lubrication
- 136.A technician needs to replace a cracked crankcase half on a horizontally opposed reciprocating engine. What is a critical airworthiness consideration regarding crankcase halves?Reciprocating Engines
- 137.A technician is comparing combustion chamber designs used in modern turbofan engines. Which combustor design uses a single continuous liner that completely surrounds the turbine shaft, rather than several individual chambers?Turbine Engines
- 138.During a runup, a pilot notes an excessive magneto RPM drop on the left magneto that clears up after leaning the mixture briefly at higher power. What is the most probable cause of this condition?Reciprocating Engines
- 139.A technician performing magneto maintenance finds the breaker point gap set narrower than the manufacturer's specification. What effect will this have on ignition timing?Ignition and Starting Systems
- 140.A starter-generator is removed for scheduled brush inspection. The manufacturer specifies a minimum brush length of 0.50 inch, and the mechanic measures the longest remaining brush at 0.31 inch. What action is required?Engine Inspection
- 141.A technician is installing an ignition harness and connecting leads to the distributor block terminals of a magneto on a nine-cylinder radial engine. If the leads are connected to the wrong distributor block terminals, the most likely result is that the engine willIgnition and Starting Systems
- 142.A mechanic is fitting new piston rings and checks the ring end gap by placing the ring squarely in the cylinder bore and measuring the gap with a feeler gauge. The measured gap is found to be less than the manufacturer's minimum specification. If installed as-is, what is the most likely result during engine operation?Reciprocating Engines
- 143.A fuel supplier adds ethylene glycol monomethyl ether (EGME) to aviation turbine fuel before delivery. What is the purpose of this additive?Fuel, Induction and Lubrication
- 144.A subsonic turbofan engine is fitted with a fixed convergent exhaust nozzle. What effect does this nozzle design have on the exhaust gases as they pass through it?Turbine Engines
- 145.What type of pump is most commonly used as the primary pressure oil pump in a reciprocating aircraft engine lubrication system?Reciprocating Engines
- 146.A pilot reports rough engine operation after prolonged ground idling with a rich mixture during a long taxi. Post-flight inspection of the spark plugs shows dry, black, sooty deposits on the electrodes. What condition is this, and what is its primary cause?Ignition and Starting Systems
- 147.During a run-up, a constant-speed propeller momentarily exceeds its selected RPM setting. How does the governor respond to correct this overspeed condition?Propellers
- 148.An aircraft's fuel tank has a usable capacity of 52 gallons of 100LL aviation gasoline. If avgas weighs 6 pounds per gallon, what is the total fuel weight when the tank is full?Fuel, Induction and Lubrication
- 149.While studying magneto theory, a technician learns about the E-gap angle. What does the E-gap represent?Ignition and Starting Systems
- 150.A mechanic is inspecting a turbine engine's fuel-oil heat exchanger (fuel-oil cooler) during a scheduled inspection. What is the primary purpose of this component?Fuel, Induction and Lubrication