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174 Cards in this Set
- Front
- Back
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What is the purpose of dynamic dampers on crankshafts?
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Reduce vibrations.
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What types of bearings are generally found in reciprocating engines?
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Plain, ball, roller bearings.
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Name the different types of piston rings.
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Oil, compression, oil scraper.
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What could result from incorrectly installed piston rings?
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Excessive oil consumption.
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What is used to help prevent valve surge or floating in an aircraft engine?
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Two or more springs are used on each valve.
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On engines equipped with hydraulic valve lifters, what should the running valve clearance be?
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Zero.
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What is the purpose of valve overlap?
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Better volumetric efficiency.
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What indications are given in the event of leaking or open primer while the engine is running?
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Engine won't idle properly.
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When pulling a propeller through, a hissing sound is heard, indicating valve blow-by. What procedure should be performed next?
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Compression check.
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What is the purpose of performing a compression test?
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To make sure valves, piston rings are sealed.
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When an engine is overhauled, how is the total time affected? When an engine is rebuilt, how is its operating history affected?
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Total time has to be continued and logged from last overhaul, if overhauled from manufacturer, is its granted a zero time status.
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Name some of the precautions that should be performed prior to engine removal.
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Disconnect battery, shut off fuel, chock wheels, install tail stand.
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What does it mean if an engine part is within "serviceable limits"?
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Part is within manufacturer's limits and can be used.
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How can a lose stud in an engine crankcase be repaired?
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Remove stud, inspect hole, use helicopter-coil if necessary.
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What publication is used to check an engine for normal operation?
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Manufacturers maintenance manual.
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What inspection should be performed on an engine that has been in storage?
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Inspection for corrosion damage.
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Where would a carburetor air temperature bulb be located?
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Ram air intake duct.
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What is the fuel pressure range on float type carburetors?
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3-5 psi.
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What unit of measure is generally used to indicate fuel flow?
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Pounds per hour.
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What does the manifold gauge indicate and how is it calibrated?
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By absolute pressure in manifold and calibrated in inches of mercury.
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What directly controls manifold pressure?
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Throttle opening, engine RPM.
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Explain the main difference and advantage of turbofan over turbojet engines.
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Additional thrust without increasing fuel flow.
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Name the major components in gas turbine engine.
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Inlet, compressor section, combustion section, turbine section, exhaust section, gearbox and accessory.
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Name two types of compressors commonly used in turbine engines.
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Axial and centrifugal flow.
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Name two different methods for attaching turbine engine rotor blades to a rotor disks.
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Dove tail type root, bulb type root.
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What are the different types of combustion chambers used in turbine engines?
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Can, annular, can-annular, reverse flow annular.
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What prevents the combustion chambers from burning?
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Cooling air along the inside of the liner.
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What is the purpose of the interconnecting tubes attached between can-type combustion chambers?
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Flame propagation during start.
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What are carbon seals used for in turbine engines?
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Oil deals for rotor shaft bearings.
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What is shaft horsepower?
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Indication of torque by turboprop or turboshaft engines.
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Name the main components in an APU.
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Turbine for power and bleed air, generator.
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When is the greatest demand placed on an APU?
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Supplying bleed air.
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How is an APU generally started?
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Electrical starter.
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Where does the APU get its fuel supply?
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Aircraft's main tanks.
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How is an APU shut down and why is this procedure used?
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Closed bleed air valve, ran for a few minutes to cool down.
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Why are compressor washes performed and what methods are commonly used?
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Remove contaminants and improve performance, fluid and grit wash are used.
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Name the different types of compressor blade damage that may be found during inspection?
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Dents, cracks, galling, pitting, scratches, burrs, gouges.
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Name the different types of compressor blade damage that may be found during inspection?
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Dents, cracks, galling, pitting, scratches, burrs, gouges.
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What kind of markers can be used to mark the parts in hot and cold sections during repair?
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Felt tip marker, chalk, layout dye.
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What criteria determines replacement of life limited turbine engine components?
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Cycles, hour, calendar time.
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How are gas turbine engine tachometer calibrated?
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In percent RPM.
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On a turbine engine, what is the engine pressure ratio and what does it indicate?
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It's the ratio between total inlet pressure and total exhaust pressure, indicates thrust.
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On a turbine engine, what is the engine pressure ratio and what does it indicate?
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It's the ratio between total inlet pressure and total exhaust pressure, indicates thrust.
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Can the EGT system on a turbine engine be check without running the engine?
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Yes, checking resistance on thermocouples.
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Name the three components on the induction system of a reciprocating engine.
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Air scoop, carburetor or fuel control, intake manifold.
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How is induction icing categorized?
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Impact ice, fuel evaporation ice, throttle ice.
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Is carburetor throttle ice more likely to occur at a higher or lower power setting? Why?
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Lower power settings, throttle is closed giving a larger surface area for ice to accumulate.
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What might be an indication of leaking intake pipes?
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Engine runs rough at low RPM.
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What might be an indication of leaking intake pipes?
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Engine runs rough at low RPM.
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What happens to engine power when carburetor heat is applied?
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Drop in power.
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What are two types of supercharged induction systems?
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Internal and external driven.
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What is used to power a turbocharger?
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Exhaust gas.
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What function does a turbocharger waste gate perform?
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Controls exhaust gas into the turbo, which controls the boost pressure.
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What are the most common ways to control a waste gate?
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Mechanically, actuator driven by oil pressure.
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Where are bellmouth inlet ducts typically found?
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Helo engines.
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What are the most common methods used for anti icing of turbine engine inlet ducts?
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Bleed air, heating elements.
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What is the purpose of the exhaust system?
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To remove high temperature gases.
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Name two types of reciprocating engine exhaust systems?
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Short stack, collector system.
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What drawback in using collector type exhaust system is more than offset when used on turbocharged engines?
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Loss of horsepower because of back pressure.
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What drawback in using collector type exhaust system is more than offset when used on turbocharged engines?
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Loss of horsepower because of back pressure.
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What type of exhaust system is used on turbocharged engines?
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Collector type.
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What kind of material is normally used to make muffler shrouds found in exhaust system?
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Stainless steel.
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Why is an exhaust system failure considered a severe hazard?
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Carbon monoxide poisoning, loss of power, fire.
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What is an indication of exhaust gas leak?
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Black soot from the leak.
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Where are the most common places to find leaks in an exhaust system?
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Welds, clamps, flanges.
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Name the components of a typical turbine exhaust nozzle.
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Tail cone, exhaust ducts.
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What are the two most commonly used types of thrust reversers?
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Clamshell, cascade.
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What are some of the sources used to heat the fuel in a turbine engine fuel system?
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Bleed air, oil.
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What are the most common types of fuel metering systems used on small reciprocating engines?
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Float type carburetor, pressure injection carburetor, direct fuel injection.
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What generally causes spark plug fouling?
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To much rich mixture at idle.
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What is the purpose of an accelerating system?
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Provides immediate but short increase in fuel flow.
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What is a carburetor economizer system?
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It provides a richer mixture at high power settings.
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When the mixture is placed idle cut off position, a slight rise in RPM is noted prior to the engine decelerating. What does this indicate?
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Mixture is set correctly.
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When the mixture is placed idle cut off position, a slight rise in RPM is noted prior to the engine decelerating. What does this indicate?
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Mixture is set correctly.
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What maintains the fuel pressure in a pressure injection carburetor?
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Engine driven fuel pump.
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How does an automatic mixture control (AMC) function?
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A brass bellow connected to the fuel metering system expands and contracts with changes in pressure and temperature and adjusts the mixture.
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What purpose do turbine engine control units serve?
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Automatically meters fuel.
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What are two basic types of engine fuel control units?
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Hydromechanical, electronic.
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What are the engine variables detected by the fuel control unit?
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Power level, RPM, compressor inlet temperature, compressor inlet pressure, compressor discharge pressure, burner pressure.
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What are the two major components of a supervisory electronic engine control?
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Electronic control unit, hydromechanical fuel control.
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What are the different engine indications used for trimming a turbine engine?
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EPR or R.P.M.
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What type of pump can vary the amount of fuel discharge regardless of speed?
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Variable displacement pump.
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What is the purpose of a pressure relief valve in a constant displacement pump?
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Returns excess fuel to the inlet side of pump.
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What type of engine driven fuel pump is widely used other than gear or piston pumps?
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Rotary vane type.
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What function do fuel boost pumps perform?
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Supplies pressured fuel to the fuel pump.
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What is a commonly used type of fuel boost pump?
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Centrifugal type.
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What causes vapor lock and why is it of concern?
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It's caused be insufficient fuel pressure.
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Name the two categories of turbine engine pumps.
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Constant, variable displacement.
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What category is a gear type pump classified in?
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Constant displacement.
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What are the functions of the pressurizing and dump portions of a pressurizing and dump valve?
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The pressurizing portion provides primary and secondary fuel flow, dump portion allows fuel to drain from manifold after shutdown.
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What purpose do fuel selector valves serve?
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Allows for tank to engine selection, a way to shut off fuel flow.
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What components of a starter generator require periodic inspection?
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Commutator, brushes.
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What components of a starter generator require periodic inspection?
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Commutator, brushes.
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When should ignition ideally occur?
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When piston reaches top dead center of compression stroke.
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Why are dual magnetos used in the engine ignition system?
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Combustion efficiency, redundancy.
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Name the components of a high tension magneto system.
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Rotating magnet, iron core, pole shoes.
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Name the three main circuits of a high tension magneto system.
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Magnetic, primary, secondary.
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What is e-gap angle?
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A few degrees beyond the natural position of a rotating magnet.
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What is the P-lead and how does it function?
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It's connected to the primary circuit, when either side is selected the opposite side is grounded.
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What is the function of a duty cycle in relation to a turbine engine ignition system?
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Allows operation of the system for a given amount of time, and followed by a cool down period.
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What are the three main components of a turbine engine ignition system?
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Exciters, high tension leads, igniters.
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When the engine is operating, what does an ammeter/ loadmeter indicated when connected to: 1. Battery positive lead? 2. Generator output lead?
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With the battery positive lead it shows if it's charging or not, with the generator output lead it shows current.
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What is done to ensure that each generator shares the load in a multiple generator system?
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Being in parallel.
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What is the most common type of alternator used in most aircraft AC systems?
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Three phase alternator.
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What are some of the methods used to maintain 400 hertz alternator output frequency on large turbojet or turbofan engines?
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Constant speed drive (CSD), integrated drive generators, variable speed constant frequency (VSCF).
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Name the major parts of a DC motor.
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Armature, field, brushes, frame assembly.
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Name three types of DC motors.
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Series, shunt, compound.
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What is the size standard for electrical wire used in U.S. Manufactured aircraft?
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American wire gauge (AWG).
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How are wire sizes represented?
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A numbered gauge size.
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What is the maximum slack allowed between the supports of a single wire or bundle installation?
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Not over half inch.
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Why are wires bonded on powerplant installations?
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To provide a current return path, prevent static discharge.
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A reciprocating engine is found to have excessive oil consumption without evidence of any oil leak. What is the likely cause?
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Piston rings worn or broken.
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A reciprocating engine is found to have excessive oil consumption without evidence of any oil leak. What is the likely cause?
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Piston rings worn or broken.
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What are the functions of lubricating oil in reciprocating engines?
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Reduce friction and heat.
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Why do aircraft reciprocating engines use relatively high viscosity oil?
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High temperature and pressures, large operating clearances.
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Why do oil reservoirs have expansion space?
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Thermal expansion, foaming.
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What can cause oil foaming?
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Oil Level to high, contaminated or diluted.
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What controls oil pressure in a gear type oil pressure pump?
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Pressure relief valve.
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What type of oil is used in a turbine engine oil system?
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Synthetic.
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Where are oil screens or filters most likely located in a turbine engine oil system?
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Scavenge system, before the oil yet, (last chance).
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Name two types of turbine engine oil coolers.
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Air or fuel cooled.
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What is the purpose of cooling find?
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Provides cooling surface to remove heat with air.
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What are the reasons for using engine cowlings, baffles and cowl air seals?
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Streamlines engine, provides airflow to cool cylinders.
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What is the purpose of cowl flaps and how are they operated?
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Controls airflow through the cowling, operated mechanically, electrically, hydraulically.
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Where should cowl flaps be positioned for ground operations?
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Fully open.
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Where should cowl flaps be positioned for ground operations?
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Fully open.
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Why is cowl flap adjustment important?
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Movement must be within tolerance to keep head temperature in limits.
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How are turbine engines cooled?
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By air passing through the engine, about 75% is for cooling.
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What is the approximate percentage of air passing through the turbine engine that is used for cooling rather than combustion?
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75%.
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What types of fire detectors systems are used for engine fire detection?
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Overheat, rate of rise, flame detectors.
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How does a thermal switch fire protection system operate?
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Once a Predetermined temperature is reached a switch closes causing a warning.
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How many thermal switches are needed in a thermal switch fire protection system?
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At least one.
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What kind of fire detection system allows more complete coverage than a spot type system?
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Continuous loop type.
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What electrical power is required for a thermocouple fire protection system to operate?
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Thermocouple produced power and aircraft electrical.
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What is the likely cause of a false fire warning?
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The loop is bent or kinked.
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How are fire extinguishing agents distributed?
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Perforated tubes, discharge nozzles.
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What is the purpose of the discharge cartridge and how is it activated?
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(Squib) Explosive projectile into frangible disk.
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What do the red and yellow discs in a fire extinguishing system indicate?
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Yellow: normal discharge, red: thermal discharge.
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How are some wooden propeller blades protected from wear and damage? |
Metal tipping on the leading edge. |
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What what are the functions of a constant speed propeller governor? |
It boots engine oil pressure before it enters the propeller hub and adjust oil flow to the prop hub to change pitch. |
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What what are the functions of a constant speed propeller governor? |
It boots engine oil pressure before it enters the propeller hub and adjust oil flow to the prop hub to change pitch. |
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What is the purpose of propeller counterweights? |
Centrifugal force acting on the counterweights cause the blade angle to increase. |
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What is meant when a propeller governor is in an "on-speed" condition? |
The speeder spring and flyweight forces are in balance. |
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What is meant when a propeller governor is in an "on-speed" condition? |
The speeder spring and flyweight forces are in balance. |
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How is a constant speed feathering propeller feathered? |
Releasing oil pressure in the governor, the counterweights and feathering spring move the propeller into feather. |
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What is "alpha range" and "beta range" and where are they found? |
"Alpha range" is normal operation (in flight), "beta range" is minimum thrust or reverse thrust (ground operation). |
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What propeller repair can be performed by a certified mechanic with powerplant rating? |
Only minor repairs. |
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How are wooden propellers generally cleaned? |
Brush or cloth with warm water and mild soap. |
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How are wooden propellers generally cleaned? |
Brush or cloth with warm water and mild soap. |
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Where would you find the correct method and technique for cleaning an aluminum propeller and hub? |
Propeller manufacturers maintenance instructions. |
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What type of nondestructive testing should be accomplished to a propeller after blending? |
The procedures recommend by the manufacturer. |
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How can repair file marks be removed from an aluminum propeller? |
Fine sandpaper. |
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When performing a static balance on a two bladed propeller, what position must the propeller be placed in when measurements are taken? |
Vertically and horizontally. |
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When performing a static balance on a two bladed propeller, what position must the propeller be placed in when measurements are taken? |
Vertically and horizontally. |
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What is a propeller protractor used for? |
To measure blade angle. |
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What controls both manifold pressure and RPM on engine equipped with a fixed pitch propeller? |
Throttle. |
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What publications can be used as a guide for 100 hour inspection on aircraft engines? |
Manufacturers maintenance manuals, FAR part 43 appendix D. |
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How do you identify the engine serial number? |
Data plate. |
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Prior to returning a reciprocating engine to service after a 100 hour inspection, what operational checks must be performed? |
Check Power output, magnetos, fuel and oil pressure, cylinder and oil temperature. |
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Where are life limited parts of an engine listed? |
Engine maintenance manual, type certificate data sheet. |
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Where are life limited parts of an engine listed? |
Engine maintenance manual, type certificate data sheet. |
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Where can engine operating limits be found? |
Engine manual, type certificate data sheet, aircraft manufacturer maintenance manual. |
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Where are life limited parts of an engine listed? |
Engine maintenance manual, type certificate data sheet. |
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Where can engine operating limits be found? |
Engine manual, type certificate data sheet, aircraft manufacturer maintenance manual. |
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What inspections must be performed on turbine engine if the exhaust gas temperature exceeds limitations? |
Hot section inspection. |
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Where are life limited parts of an engine listed? |
Engine maintenance manual, type certificate data sheet. |
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Where can engine operating limits be found? |
Engine manual, type certificate data sheet, aircraft manufacturer maintenance manual. |
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What inspections must be performed on turbine engine if the exhaust gas temperature exceeds limitations? |
Hot section inspection. |
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What FAA approval are required when installing an engine that is not on the aircraft type certificate? |
Supplemental type certificate, FAA field approval. |
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Where are life limited parts of an engine listed? |
Engine maintenance manual, type certificate data sheet. |
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Where can engine operating limits be found? |
Engine manual, type certificate data sheet, aircraft manufacturer maintenance manual. |
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What inspections must be performed on turbine engine if the exhaust gas temperature exceeds limitations? |
Hot section inspection. |
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What FAA approval are required when installing an engine that is not on the aircraft type certificate? |
Supplemental type certificate, FAA field approval. |
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What are possible causes for a turbojet or turbofan engine having high exhaust gas temperatures, low R.P.M., and high fuel flow at all engine pressure ratios? |
Turbine damage, loss of turbine efficiency due to wear. |
