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FAA Aviation Mechanic Powerplant (AMP) practice questions

335 free questions with answers and explanations.

Practice test
  1. 151.A high-bypass turbofan engine incorporates an active clearance control (ACC) system on the turbine case. How does this system improve engine performance?Turbine Engines
  2. 152.A turbine engine fuel nozzle contains two separate internal flow passages that both discharge fuel from the same tip: one supplies fuel during starting and low power, and the other adds fuel flow as power is increased. This nozzle design is called aTurbine Engines
  3. 153.A mechanic is inspecting the integral fuel tanks of a transport category aircraft wing and notes internal baffle plates within the tank structure. What is the primary purpose of these baffles?Fuel, Induction and Lubrication
  4. 154.An aircraft mechanic is inspecting a turbocharged reciprocating engine and finds the wastegate stuck in the fully closed position. What is the most likely operational consequence?Fuel, Induction and Lubrication
  5. 155.A radial engine ignition system combines an induction vibrator with a retard breaker to produce a rapid series of high-energy sparks at a retarded timing position during engine start. This system is known asIgnition and Starting Systems
  6. 156.A technician is performing the internal timing of a magneto prior to installing it on an engine. What is the technician trying to accomplish during this procedure?Ignition and Starting Systems
  7. 157.During a normal turbine engine start sequence, at what point should the starter typically be disengaged?Ignition and Starting Systems
  8. 158.During overhaul, a technician measures a crankshaft main journal and finds it worn beyond the maximum allowable service limit but otherwise structurally sound. The crankshaft is sent out and reground to the next standard undersize dimension. What additional step is required to properly complete this repair before the crankshaft can be reinstalled?Reciprocating Engines
  9. 159.During an annual inspection, a technician finds a small crack in the exhaust muffler shroud of a normally aspirated reciprocating engine that uses a cabin heat system drawing air around the muffler. Why is this discrepancy considered critical and requiring immediate correction?Engine Inspection
  10. 160.During troubleshooting, a technician finds a magneto producing a weak, sputtering, blue spark accompanied by badly burned and pitted breaker points. Which component is most likely defective, allowing excessive arcing at the points and preventing rapid collapse of the magnetic field?Reciprocating Engines
  11. 161.A mechanic is comparing supercharging methods on two reciprocating engines. Engine A uses a gear-driven supercharger powered directly by the crankshaft, while Engine B uses a turbocharger. What is a key operational difference between these two systems?Fuel, Induction and Lubrication
  12. 162.A mechanic reads an oil container labeled 'SAE 15W-50.' What does this designation indicate about the oil?Fuel, Induction and Lubrication
  13. 163.During acceleration from idle to takeoff power, a turbofan engine's control system automatically closes the compressor bleed (anti-surge) valve as N2 increases. What is the primary purpose of this bleed valve during low-speed operation?Turbine Engines
  14. 164.A turbine engine's axial compressor has a measured inlet total pressure of 14.7 psi and a discharge total pressure of 220.5 psi. What is the compressor's overall pressure ratio?Turbine Engines
  15. 165.A high-bypass turbofan engine has a fan (bypass) airflow of 800 lb/sec and a core airflow of 100 lb/sec. What is the engine's bypass ratio?Turbine Engines
  16. 166.While installing a magneto, a technician confirms the breaker points just begin to open (correct E-gap) when the No. 1 piston is at the specified degrees BTDC, but notices the distributor rotor is not aligned with the No. 1 terminal segment in the distributor block. What action should the technician take to correct this?Ignition and Starting Systems
  17. 167.Most horizontally opposed and radial reciprocating aircraft engines use a dual ignition system with two spark plugs per cylinder. What is the primary reason for this design?Reciprocating Engines
  18. 168.A technician is troubleshooting a counterweight-type constant-speed propeller. If governor oil pressure to the propeller is lost, what happens to the blade pitch?Propellers
  19. 169.A technician is servicing a propeller ice protection system on a turboprop aircraft. The system uses resistance heating elements bonded to the blade leading edges, cycled on and off by a timer. What type of propeller ice protection system is this?Propellers
  20. 170.A technician inspects a turbine engine fuel system component that uses hot engine oil or compressor bleed air to raise the temperature of the fuel before it reaches the fuel control unit and filters. What is the primary purpose of this fuel heater?Turbine Engines
  21. 171.An overhaul technician inspects a crankshaft and finds pendulum-type counterweights attached to the crankshaft cheeks with pins riding in oversized holes. What is the primary function of these components?Reciprocating Engines
  22. 172.During overhaul of a wet-sump reciprocating engine's oil pump, a mechanic measures excessive gear-to-housing clearance beyond the manufacturer's limits. What is the most likely operational effect of this condition?Fuel, Induction and Lubrication
  23. 173.During a ground run of a reciprocating engine equipped with a float-type carburetor, a mechanic notices that fuel pressure at the carburetor inlet rises well above the specified limit as engine RPM increases, and the mixture becomes excessively rich. Which defect in the engine-driven fuel pump is the most likely cause?Fuel, Induction and Lubrication
  24. 174.During overhaul inspection of a horizontally opposed engine's crankcase, a technician measures the stretch of each through-bolt using a specialized dial-bore gauge to check for permanent elongation. One through-bolt shows stretch exceeding the manufacturer's maximum allowable limit. What is the significance of this finding?Engine Inspection
  25. 175.A technician is comparing forced induction systems on two reciprocating engines. Engine A uses a mechanically driven supercharger, while Engine B uses a turbocharger. Which statement correctly describes the mechanically driven supercharger?Reciprocating Engines
  26. 176.During a 100-hour inspection required by 14 CFR Part 43, Appendix D, a technician is reviewing the powerplant inspection checklist. Which of the following is specifically listed as an item that must be inspected on the engine group?Engine Inspection
  27. 177.Before performing maintenance on a turbine engine's capacitor discharge (CD) ignition exciter unit, a technician mustIgnition and Starting Systems
  28. 178.A student mechanic asks why some reciprocating engines use an impulse coupling on one magneto. What is the primary purpose of this device?Ignition and Starting Systems
  29. 179.A technician inspects a turbofan engine's thrust reverser system. During deployment, blocker doors close off the bypass duct and fan discharge air is redirected forward through a series of fixed vanes to produce reverse thrust. These vanes are calledTurbine Engines
  30. 180.During overhaul, a technician measures a cylinder barrel and finds that the diameter near the top (near the cylinder head) is slightly smaller than the diameter near the bottom of the barrel, even though the cylinder is within new limits. What does this design feature accomplish?Reciprocating Engines
  31. 181.A technician turns the ignition switch to OFF before pulling the propeller through by hand, but the engine continues to fire on one magneto. What is the most likely cause of this hazardous condition?Ignition and Starting Systems
  32. 182.A technician is troubleshooting a float-type carburetor and needs to explain to an apprentice why fuel flow increases as engine speed increases. Which principle best explains this?Fuel, Induction and Lubrication
  33. 183.A mechanic disconnects a magneto primary (P-lead) from the ignition switch to perform maintenance, but does not ground the lead to the engine or airframe. What hazard does this create?Reciprocating Engines
  34. 184.A technician tests a reciprocating engine's high-tension ignition harness leads using a megohmmeter and finds insulation resistance readings well below the minimum value specified in the maintenance manual. What does this result most likely indicate?Engine Inspection
  35. 185.On a large radial reciprocating engine, one connecting rod is attached directly to the crankpin of the crankshaft, and the remaining connecting rods for that row of cylinders attach to knuckle pins on that rod. What is this central connecting rod called?Reciprocating Engines
  36. 186.During overhaul, a mechanic inspects an oil cooler's thermostatic bypass valve. Which statement correctly describes its function when the engine oil is cold?Fuel, Induction and Lubrication
  37. 187.A mechanic is servicing a turbine engine oil system and notes that the manufacturer specifies a synthetic ester-based lubricant rather than a petroleum-based mineral oil. What is the primary reason synthetic oil is used in turbine engines?Fuel, Induction and Lubrication
  38. 188.A technician examines a turbine engine's main shaft where it passes through a stationary case section. A series of thin circumferential knife-edge ridges on the rotating shaft are positioned very close to a stationary honeycomb or abradable lining. What is the primary purpose of this labyrinth seal arrangement?Turbine Engines
  39. 189.A turbine engine uses annular-gap igniter plugs instead of the massive-electrode plugs common on reciprocating engines. What design feature allows these igniters to fire reliably even when fouled with carbon or fuel residue?Ignition and Starting Systems
  40. 190.A line technician draws a fuel sample from the aircraft's fuel strainer sump and adds a chemical water-detecting capsule to the sample. The capsule immediately changes color, confirming the presence of water in the fuel. What should the technician do next?Fuel, Induction and Lubrication
  41. 191.A technician is troubleshooting a capacitance-type fuel quantity indicating system on a transport-category aircraft. Which statement best describes the principle used by this system to measure fuel quantity?Fuel, Induction and Lubrication
  42. 192.A turbofan engine's Engine Pressure Ratio (EPR) is defined as turbine discharge total pressure (Pt7) divided by compressor inlet total pressure (Pt2). If Pt7 is 34.8 psi and Pt2 is 14.5 psi, what is the EPR?Turbine Engines
  43. 193.A turbine engine nacelle fire detection system uses a continuous sensing element routed throughout the fire zone. As temperature rises anywhere along the element, its electrical resistance decreases, allowing current to flow and trigger the fire warning. What type of system is this?Turbine Engines
  44. 194.A technician is torquing the cylinder base (hold-down) nuts on a horizontally opposed engine cylinder that has just been reinstalled. What is the correct general procedure for applying final torque to these nuts?Reciprocating Engines
  45. 195.A technician is calibrating a differential compression tester before use and applies 100 psi to the master orifice. The tool's specification calls for the orifice to read 40-46 psi at this input pressure. The gauge shows 50 psi. What action should the technician take?Engine Inspection
  46. 196.A technician performs a borescope inspection of a turbine engine's hot section as part of a scheduled inspection program. Which type of defect is this inspection method primarily intended to detect?Turbine Engines
  47. 197.A turbine engine combustor operates with an overall fuel-air ratio of roughly 60:1 by weight, far leaner than the chemically correct (stoichiometric) ratio of about 15:1. Why is the combustor designed to run this lean overall?Turbine Engines
  48. 198.A technician performs a differential compression check on a cylinder using a calibrated orifice tester and obtains a reading of 60/80. During the test, an assistant reports a steady hissing sound from the crankcase breather/oil filler with the piston at top dead center on the compression stroke. This indicates leakage past the:Reciprocating Engines
  49. 199.A technician disassembling a cylinder finds that the exhaust valve stem is hollow and partially filled with a metallic substance. What is the purpose of this design?Reciprocating Engines
  50. 200.During cruise, a turboprop engine's torque drops sharply due to an internal engine malfunction while the propeller governor continues trying to hold selected RPM by moving toward a finer pitch, which would create high drag and yaw. Which propeller system is designed to sense this condition and automatically move the blades toward a coarser pitch to reduce drag?Propellers