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167 Cards in this Set
- Front
- Back
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What is the main advantage of a horizontally opposed engine over a radial engine for powering modern aircraft?
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horizontally opposed has smaller frontal area and is easier to streamline than a radial
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How many throws are there in the crankshaft of a six-cylinder horizontally opposed engine?
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Six
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What kind of connecting rod arrangement is used in a radial engine?
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A master rod connects the single throw of the crankshaft with a piston. All of the other pistons are connected to the master rod with link rods.
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Of what material are most piston rings made
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Gray cast iron.
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What is the reason for using hydraulic valve lifters in an aircraft engine?
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keeps all of the clearance out of the valve operating mechanism. This decreases the wear of the valve train components.
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At what speed does the camshaft turn, relative to the crankshaft speed in a horizontally opposed engine?
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one half of the crankshaft speed.
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What kind of main bearings are used in a horizontally opposed engine?
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Steel-backed, lead-alloy bearing inserts.
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On what stroke is the piston of a reciprocating engine when the intake valve begins to open?
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On the exhaust stroke.
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On what stroke is the piston of a reciprocating engine when the exhaust valve begins to open?
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On the power stroke.
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Why are both the hot and cold valve clearances given for most radial engines?
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The hot clearance is given for valve timing purposes. The timing is adjusted with the valves in cylinder number one, set with the hot clearance. When the timing is set, all of the valves are adjusted to their cold clearance.
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What is meant by a cam-ground piston?
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A piston that is not perfectly round. Its dimension parallel with the wrist pin is several thousandths of an inch less than its dimension perpendicular to the wrist pin. When the piston reaches operating temperature, the metal in the piston pin boss expands enough that the piston becomes perfectly round.
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Where is the piston in a reciprocating engine when the ignition spark occurs?
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About 30 degrees of crankshaft rotation before the piston reaches top center on the compression stroke.
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What is meant by a full-floating wrist pin?
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A wrist pin that is not clamped in either the piston or the connecting rod. Full-floating wrist pins are kept from scoring the cylinder walls by soft metal plugs in their ends.
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Why do most aircraft reciprocating engines use more than one spring on each valve?
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By using more than one spring and having the wire diameter and pitch of the springs different, valve float is minimized. The springs have different resonant frequencies, so at least one spring will always be exerting a force on the valve.
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Would excessive valve clearance cause the valves to open early or late?
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Excessive clearance will cause the valve to open late and close early.
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What is the purpose of valve overlap in a reciprocating engine?
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Valve overlap allows the inertia of the exhaust gases leaving the cylinder to help the fresh induction charge start flowing into the cylinder.
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What type of piston rings are installed on the pistons of an aircraft reciprocating engine?
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Compression rings, oil control rings, and oil wiper rings.
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Why are some exhaust valves partially filled with metallic sodium?
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The metallic sodium melts at engine operating temperature and sloshes back and forth inside the hollow valve. It picks up heat from the valve head and transfers it into the valve stem, so it can be transferred to the cylinder head through the valve guide.
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What causes detonation in an aircraft engine?
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Excessive heat and pressure in the engine cylinder causes the fuel-air mixture to reach its critical pressure and temperature. Under these conditions, the mixture explodes rather than burns. This explosion is called detonation.
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Why is a compression check important for determining the condition of an aircraft reciprocating engine?
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A compression check can determine the condition of the seal between the piston rings and the cylinder walls, and the seal between the intake and exhaust valves and their seats.
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What is meant by the compression ratio of a reciprocating engine?
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The ratio of the volume of the cylinder with the piston at the bottom of its stroke to the volume with the piston at the top of its stroke.
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In What position should the crankshaft be when a magneto is being timed to the engine?
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Piston in cylinder no.1 should be about 30 degrees before top center on the compression stroke
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What is the purpose of a cold cylinder check?
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Run the engine for a few min. then shut down. Now feel which cylinder is not hot and that is the cylinder not firing.
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What is checked on engine runup to determine the operational condition of the engine?
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Idling RPM, manifold pressure, engine acceleration, engine acceleration, maximum RPM/manifold pressure, magneto drop, ignition switch safety check, prop pitch change, prop feathering, oil pressure, fuel pressure, and fuel flow
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How can you determine the firing order of an 18-cylinder radial engine?
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Begin with cylinder 1, add 11 and subtract 7 whichever will keep the numbers between 1 and 18.
1-12-5-16-9-2-13-6-17-10-3-14-7-18-11-4-15-8 |
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What are two main causes of a cylinder having low compression?
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Piston rings not seating or broken, and valves not seating or burned
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What is a hydraulic lock in a aircraft engine?
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Oil has drained past piston rings and filled combustion chamber. If the crankshaft is turned the cylinder will be locked and could cause damage to the piston, cylinder, connecting rod
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How is hydraulic lock removed from an engine?
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Remove a spark plug from the locked cylinder and drain all oil out and rotate the crankshaft. Replace spark plug
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What is a low-tension ignition system?
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A magneto with a brush-type distributor and a coil that has no secondary wiring. Low voltage is directed from the magneto to a transformer that is mounted on each cylinder; here it boosted low voltage to high voltage and is directed to the spark plug with a very short high-tension lead wire.
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What is a floating cam ring on a large radial engine?
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It is a cam ring that rides on a shelf-type bearing with a large amount of clearance between the bearing and the ring. When adjusting the valves the pressure of the valve springs on the opposite side of the engine must be removed so the cam ring will be tight against the bearing for the valves being adjusted.
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Why is valve clearance adjusted on radial engines, but not on most horizontally opposed engines?
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Most horizontally opposed engines have hydraulic valve lifters that keep all of the clearance out of the valve train. Radial engines have solid lifters.
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What must be inspected to determine the airworthiness of an engine installation?
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The propeller, lube system, ignition system, fuel metering system, cooling and exhaust systems
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Where can you find the correct grade of fuel and amount of engine lube oil for an engine?
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TCDS for the aircraft
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What are the basic steps in troubleshooting an engine installation?
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Know how the system should operate
Observe how the system is operating Divide the system to fine the trouble Look for the obvious problems first |
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Where do you find the procedures to follow when correcting a defective condition in an aircraft engine?
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Engine maintenance manual
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Where do you find instructions for removing an engine?
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Aircraft maintenance manual
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What must normally be done to a nose-wheel airplane before removing an engine?
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Tail of the aircraft should be supported
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What should be done to the cylinders to protect them from rust and corrosion when preparing the engine for long storage?
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Spray a preservative oil inside the cylinders and replace the spark plugs with desiccant plugs
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What should be used to cover the ends of fuel and oil lines that have been disconnected from the engine?
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Correct plugs or caps. Never use tape
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What is meant by a QEC engine assembly?
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It is a quick engine change. The engine is on its mounts and all accessories are installed. A minimum time is required to change out the engine. All it needs are the controls, wiring, and fluid lines to be connected.
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What is meant by rigging the engine controls so they have some "cushion"?
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The control on the engine component must contact its stop before the control handle in the cockpit reaches its stop. This causes the control handle to spring back a slight amount when it is moved to the extent of its travel
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What are two ways of pre-oiling an engine?
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Before the spark plugs are installed and after the oil tank or sup is filled, turn the engine over with the starter until oil runs out of the fitting to which the oil pressure gage connects
Use a pre-oiler tank. Air pressure forces oil through all of the passages until some of it flows from the oil pressure gage fitting |
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TURBINE ENGINES
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TURBINE ENGINES
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What are the two basic sections of a turbine engine?
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The hot section and the cold section.
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What are the two basic types of compressors that are used in aircraft turbine engines?
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Axial-flow and centrifugal.
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What is the purpose of the stators in an axial-flow compressor?
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The stators convert some velocity energy into pressure energy and change the direction of the air so it is proper for the next stage of rotors.
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What are three types of combustors used on aircraft turbine engines?
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Can-type, annular-type, and can-annular-type.
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How many igniters are there normally in an aircraft turbine engine?
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Two
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What is the main purpose of the turbine nozzle in an aircraft turbine engine?
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The turbine nozzle directs the hot gases as they leave the combustors so they will turn the turbine wheel with maximum efficiency.
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What is meant by a free-turbine turboshaft engine?
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A turboshaft engine that has a turbine wheel, or stage of turbine wheels, that is not used to drive the compressor of the gas generator section of the engine. This free turbine drives the propeller in a turboprop engine or the transmission and rotor of a helicopter.
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Why do some axial-flow turbine engines have more than one set of turbines and compressors?
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A two-spool turbine engine has a low-pressure and a high-pressure compressor, each driven by its own turbine. The two independent systems operate at the speed at which they are most efficient.
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What kind of bearings are used to support the rotor shaft of an aircraft turbine engine?
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Anti-friction bearings, such as ball bearings or roller bearings.
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What is meant by a turbofan engine?
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An axial-flow turbine engine in which the first stage of compressor blades are lengthened, so they can force air around the outside of the gas generator portion of the engine.
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Where can you find the limits of repair allowed for the compressor blades of an aircraft turbine engine?
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In the FAA-approved service manual issued by the manufacturer of the engine.
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Why is it important that a turbojet engine be allowed to cool before it is shut down after it has been operated at a high power setting?
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If the engine is shut down while it is hot, there is a possibility that the shroud will contract around the turbine wheel and seize the rotor.
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What is meant by a hung start in a turbine engine?
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A start in which ignition occurs, but the engine does not accelerate to a self-sustaining speed.
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What is meant by a hot start in a turbine engine?
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A start in which ignition occurs, but the internal temperatures go high enough that they can damage the engine.
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What is meant by creep of the turbine blades?
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A condition of permanent elongation of the turbine blades. Creep is caused by the high temperatures and the high centrifugal loading imposed on the blades.
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How is the compressor of a turbine engine cleaned?
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An emulsion-type cleaner is sprayed through the engine while it is being motored by the starter or operated at a low speed. The wash is followed by a clean water rinse.
More vigorous cleaning is done by injecting a mild abrasive, such as ground-up apricot pits or walnut shells, into the engine while it is operating at low speed. |
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Where is water injected into a turbine engine for cooling purposes?
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Into the compressor inlet and into the engine diffuser case.
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At what point in a turbine engine is the temperature the highest?
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At the inlet to the high-pressure turbine.
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What is the function of the interconnect tubes between the cans of a turbine engine that uses can-type combustors?
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These tubes allow the flame to travel from the cans that contain the igniters to all of the other cans when the engine is being started.
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What are two types of thrust reversers that are used on turbojet engines?
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The mechanical blockage-type and the aerodynamic blockage-type.
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What is meant by trimming a turbojet engine?
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Adjusting the fuel control to get the correct idling and maximum-thrust RPM.
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What is meant by a hot-section inspection?
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Inspection the hot section which includes the combustors, turbine, and the exhaust system
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What is meant by on-condition maintenance of a turbine engine?
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The monitoring of the engine performance at regular intervals and determining when maintenance is required based on certain operating parameters specified by the engine manufacture
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What checks of a turbine engine are necessary to verify preflight condition?
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-Inspection of the cowling and all air inlet areas and attachment of the engine to the airframe.
-Inspection of the inlet guide vanes and the first stage of the compressor or fan blades. -Check for unusual noise when the compressor is rotated. -Inspection of the rear turbine, and exhaust system. -Check quantity of the lube oil for the engine and constant-speed drive unit. -Check the ignition system for operation by listening for the sparks. |
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What type of equipment should be used to determine that a turbine engine is performing up to the standard specified by the engine manufacture?
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A JetCal Analyzer/Trimmer has all of the instrumentation and cables to determine the EGT, EPR, and the other parameters specified by the engine manufacturer
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ENGINE INSPECTION
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ENGINE INSPECTION
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What determines whether or not a 100-hour inspection is required for an aircraft?
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100-hour inspections are required only on aircraft that carry persons for hire or are used to give flight instruction for hire.
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Where can you find a list of items that should be inspected on a 100-hour and an annual inspection of an aircraft engine?
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In Appendix D of 14 CFR Part 43.
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In what publication can a mechanic find the operating limitations for an aircraft engine?
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In the Type Certificate Data Sheets for the engine.
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Who is authorized to perform the powerplant inspection that is required for an annual inspection?
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An A&P mechanic who holds an Inspection Authorization.
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What are two types of compression checks that can be performed on an aircraft reciprocating engine?
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A differential compression check and a direct compression check.
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What items are checked in a hot section inspection of a turbine engine?
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The combustion section is checked for cracks or distortion. The turbine wheel, the turbine case, and the exhaust section are checked for cracks, indications of overheating, and any indication of warpage, erosion, or burning.
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What is the most common type of damage that is found in the hot section of a turbine engine?
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Cracks that are caused by the high concentration of heat in the hot section.
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Is the use of a checklist required when performing an annual or 100-hour inspection on an aircraft engine?
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Yes
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What inspection must be performed on an aircraft reciprocating engine if it has been operated on turbine fuel?
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The inside of the cylinders must be inspected with a borescope. The oil must be changed and the filters examined, and the engine given a careful run-up and operational check.
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Where can you find the model of magneto that is approved for an engine specified by the examiner?
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In the TCDS for the engine
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What is a Supplemental Type Certificate?
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An approval issued by the FAA for a modification to a type-certificated airframe, engine or component
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What paperwork is necessary for the installation of a magneto that was not approved for an engine when it was certificated, but is approved for the engine when installed according to an STC?
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A form FAA 337 must be completed stating that the installation was done in accordance with the specific STC
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ENGINE INSTRUMENT SYSTEMS
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ENGINE INSTRUMENT SYSTEMS
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In what units is the tachometer for a reciprocating engine calibrated?
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In hundreds of RPM.
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In what units is the tachometer for a turbine engine calibrated?
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In percent of the engine's rated takeoff RPM.
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Where does the manifold pressure gage used on an aircraft reciprocating engine pick up the pressure it measures?
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From the intake manifold of the engine.
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What are two types of pickups used for measuring the cylinder head temperature of a reciprocating engine?
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The thermocouple can be embedded in a gasket that is installed under the spark plug of the hottest running cylinder, or it can be in a bayonet that is held against the cylinder head by a spring.
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Why do most engine oil pressure gages have a restrictor in the line between the engine and the instrument?
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The restrictor damps out pressure pulsations in the oil to keep the needle from oscillating.
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What is used to measure the fuel flow of a horizontally opposed, fuel-injected reciprocating engine?
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A pressure gage that measures the pressure drop across injector nozzles.
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What is indicated if the needle of a ratiometer-type oil temperature indicator pegs to the high side of the dial as soon as the aircraft master switch is turned on?
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There is an open in the bulb circuit that causes the instrument to see an infinite resistance. The higher the resistance in the bulb circuit, the higher the temperature indication.
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What type of indicating system is used to measure the exhaust gas temperature of a turbine engine?
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A set of thermocouples arranged in an averaging circuit. These thermocouples are installed in the tail pipe of the engine.
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What should a thermocouple-type cylinder head temperature indicator read when the engine is not operating?
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The temperature of the outside air.
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How does a torquemeter actually measure the torque produced by an engine?
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A torquemeter is actually an oil pressure gage. The pressure it measures is produced in a torque sensor and is proportional to the amount of strain in the torsional shaft that drives the reduction gears of the turboprop engine.
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What two pressures are measured to get the Engine Pressure Ratio of a turbojet engine?
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The turbine discharge total pressure and the compressor inlet total pressure.
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Of what two materials are the thermocouples made that are used in a turbine engine exhaust gas temperature system?
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Chromel and alumel.
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What kind of mechanism is normally used to measure oil pressure in a reciprocating engine?
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A bourdon tube mechanism.
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What is measured by the tachometers used on a two-spool gas turbine engine?
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The N1 tachometer shows the RPM of the low-pressure compressor, and the N2 tachometer shows the RPM of the high-pressure compressor.
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Does the tachometer of a geared reciprocating engine indicate the speed of the crank shaft or of the propeller shaft?
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The speed of the crankshaft.
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What are three types of flow-indicating systems used for turbine engines?
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Vane-type, synchronous mass-type, and electronic motorless mass flow meters
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What do mass flow systems measure?
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The mass of the flow. This is affected by the density of the fuel which is in turn affected by the fuel temp.
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In what units is an electronic motorless mass flow meter system calibrated?
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Pounds per hour of fuel flow
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What is indicated in a turbine engine if the fuel flow for all condition is high?
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If there are other instrument abnormalities, there are possibly damaged turbine components
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Who is authorized to repair a fuel flow indicating system?
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Only repaired by an FAA approved repair station certificated for the particular instruments
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Where can you find the electrical power requirements for a fuel flow indicating system?
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Aircraft maintenance manual
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Where in the fuel system is the fuel flow transmitter located?
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Between the fuel control and the fuel nozzles
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What kind of indicating system is used to measure oil temp in a small, single-engine, general aviation airplane?
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A sealed system in which a bulb, partially filled with a highly volatile liquid, is installed inside the oil strainer. The bulb is connected to a pressure gage by a copper tube. The pressure of the gas above the liquid is proportional to the temp of the oil that surrounds the bulb, and the pressure gage is calibrated in terms of temp
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What kind of electrical instrument system is used for measuring oil temp?
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Ratiometer-type system
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What is critical in the installation of the thermocouple leads for a cylinder-head temp indicator, the length of the leads or their resistance?
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Resistance is critical, it must have the resistance specified on the indicator. This is usually 2 or 8 ohms
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What should a ratiometer temp indicator read when the electrical power is off?
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Pointer should be off scale on the low side
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What kind of tach is used on small airplanes?
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Magnetic drag tach that is similar to an automobile speedometer
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What would likely cause the pointer of a magnetic drag tach to oscillate?
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Either a dry cable connecting the indicator to the engine, or a kink in the cable housing
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Is it permissible for a mechanic with a A&P to replace the tach cable for a magnetic drag tach?
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Yes, this does not constitute a repair to an instrument
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What kind of tach is used on most large multi-engine airplanes?
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Three-phase AC electric tach
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What is measured to indicate the engine RPM with a three-phase AC electric tach?
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The frequency of the AC the tach generator produces
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What kind of indicator mechanism is used to measure manifold pressure?
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Differential bellows
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What should a manifold pressure gage read when the engine is not operating?
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Existing barometric pressure
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What is used to fill the line between a fuel pressure gage and the fuel metering system?
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A light oil such as kerosine
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What could cause a fuel pressure gage to fluctuate?
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The loss of the light oil in the line between the gage and the engine
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Is a certificated mechanic with an A&P allowed to zero the pointers on a fuel pressure gage?
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No, a mechanic is not allowed to make any repairs or alterations to an aircraft instrument
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How does a ratiometer-type oil temp gage measure the temp of the oil?
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It measures the resistance of the temp bulb. The indicator is calibrated in degrees F or C rather than in ohms
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What is the range of pressure needed for a fuel pressure gage used with a float carburetor?
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Normally from 1 to 25 psi
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ENGINE FIRE PROTECTION SYSTEMS
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ENGINE FIRE PROTECTION SYSTEMS
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Can a thermal switch-type fire detection system indicate a general overheat condition?
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No, this is a spot-type fire detection system, and it cannot indicate an overheat condition.
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Can a thermocouple-type fire detection system indicate a general overheat condition?
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No, this is a rate-of-temperature-rise-type of system, and it cannot indicate a general overheat condition.
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How is a thermocouple-type fire detection system checked for operation?
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Current is sent through the heater in the thermal test unit. This heats the thermocouple, which produces enough current to close the sensitive relay. Current through the contacts of the sensitive relay closes the slave relay and turns on the fire warning light.
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Does a break in a continuous-loop fire detection system keep the system from detecting a fire?
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No, the unit will show a fault when it is tested, but it will still warn of a fire.
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Does the pressure-type continuous-element fire detector system detect a general overheat condition, as well as a fire?
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Yes, a high temperature on a small portion of the sensor or a lower temperature over the entire sensor will cause it to release enough gas to close the diaphragm switch and warn of a fire.
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What are the two most commonly used fire extinguishing agents used for engine fires?
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Halogenated hydrocarbon, such as Halon 1301, and carbon dioxide.
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What extinguishing agent is used in the high-rate-discharge fire extinguishing systems installed in most turbojet engine installations?
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Halon 1301.
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What happens when the pilot pulls the fire-pull T-handle in the cockpit of a jet transport airplane?
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The bottle discharge switch is uncovered and armed, the generator field relay is tripped, fuel is shut off to the engine, hydraulic fluid is shut off to the pump, the engine bleed air is shut off, and the hydraulic pump low-pressure lights are deactivated.
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How can a mechanic determine the state of charge of the HRD bottles of fire extinguishing agent?
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A pressure gage on the bottle shows the pressure of the contents of the bottle.
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What method is used to discharge an HRD bottle in a turbine engine installation?
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An electrically ignited powder charge blows a knife through the seal on the bottle and discharges the contents.
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Which type of fire detection system operates on the rate of temperature rise?
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The thermocouple system.
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What is indicated if the yellow blow-out plug of the fire extinguisher system on the side of an engine nacelle is blown out?
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The built-in fire extinguishing system has been discharged by normal operation.
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What is indicated if the red blow-out plug of the fire extinguisher system on the side of an engine nacelle is blown out?
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The built-in fire extinguishing system has been discharged by a high temperature condition.
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How is a pressure-type continuous-element fire detector system checked for operation?
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Low-voltage alternating current is sent through the sheath of the detector element. This heats the element, and it releases enough gas to close the diaphragm switch.
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What are four types of engine fire detection systems?
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Thermoswitch
Thermocouple Thermistor-type continuous-loop Pneumatic-type continuous-loop |
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Why must the reference junction in a thermocouple fire detection system be thermally insulated?
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So the temp will not rise as quickly as that of the measuring junctions if a fire should occur
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What would likely cause a false fire alarm in a thermistor-type continuous-loop system?
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A kinked or pinched continuous-loop element
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If there is a break in a single-wire continuous-loop fire detector element, and the system tests bad, will it indicate the presence of a fire?
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Yes, even though it tests bad, it will still indicate the presence of a fire
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How is a pneumatic-type continuous-loop fire detection system checked for operation?
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When the test switch is closed, low-voltage AC flows through the tube that encloses the sensitive element. This current heats the element enough for it to release sufficient gas to activate the alarm switch
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What maintenance is allowed of a continuous-loop fire detection system?
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Inspect and replace as needed the continuous-loop element, the controller, and the fire warning bell and/ or light
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What is used as a fire extinguishing agent in some older aircraft?
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Carbon dioxide (co2)
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What precaution must be taken when checking the electrical circuit for igniting the powder charge in the valve of a high-rate discharge bottle?
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The current used to check the integrity of the circuit must not be high enough to ignite the powder charge
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What color and marking is used to identify the fluid lines that carry the fire extinguishing agent in an aircraft?
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Brown tape with a series of diamonds on it
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ENGINE ELECTRICAL SYSTEMS
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ENGINE ELECTRICAL SYSTEMS
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Why is stranded wire used rather than solid wire in most powerplant electrical systems?
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Solid wire is likely to break when it is subjected to vibration.
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What two things must be considered in selection of wire size when making an electrical installation in an aircraft?
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The current-carrying capability of the wire and the amount of voltage drop that is caused by current flowing through the wire.
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Why are the wires in certain electrical installations twisted together?
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By twisting the wires together, the magnetic fields caused by current flowing in the wires are minimized.
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What is used to protect a wire bundle from chafing where it passes through a hole in a bulkhead or frame?
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A grommet around the edges of the hole.
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How are electrical wires protected where they pass through an area of high temperature?
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Wires passing through these areas are insulated with high temperature insulation, and the wires are enclosed in some type of protective conduit.
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What is the minimum separation that is allowed between a wire bundle and a fluid line that carries combustible fluid or oxygen?
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A minimum of six inches.
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What is the significance of the color of the solderless connectors that are used on electrical wires?
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The color of the insulation indicates the size of wire the connector will fit. Red terminals fit 22- through 18-gage wire, blue terminals fit 16- and 14-gage wire, and yellow terminals fit 12- and 10-gage wire.
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What is the maximum number of wire terminals that may be stacked on a single stud in a terminal strip?
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Four
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What is the purpose of the shielding that is used to encase some electrical wires?
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Shielding intercepts radiated electromagnet energy and carries it to ground so it will not interfere with any nearby sensitive electronic equipment.
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Why must a switch be derated if it is used in a circuit controlling a DC electric motor?
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The initial current flowing into a DC electric motor is much higher than the current the motor uses after the armature begins to rotate. Because of this high inrush current, the controlling switches must be derated.
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What is used as the rectifier to produce direct current in a DC generator?
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Brushes and a commutator.
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How does a vibrator-type voltage regulator control the output voltage of a DC generator?
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The strength of the magnetic field produced in the voltage regulator relay is proportional to the generator output voltage. When the voltage rises above the regulated value, the relay pulls the contacts open and inserts a resistor in the generator field circuit. The contacts vibrate open and closed, putting the resistor in and out of the field circuit to control the amount of voltage the generator produces.
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What is meant by paralleling the generators of a twin-engine aircraft?
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Adjusting the voltage of the generators so they will share the electrical load equally.
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What is meant by flashing the field of a DC generator?
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Restoring the residual magnetism to the frame of a generator by passing battery current through the field coils in the same direction it flows when the generator is producing current.
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What kind of rectifier is used in a DC alternator of the type that is used on most of the modern light airplanes?
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A full-wave, three-phase rectifier made up of six silicon diodes.
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What is used to maintain a constant frequency of the alternating current that is produced by an AC alternator driven by an aircraft turbine engine?
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A hydraulic constant-speed drive unit between the engine and the alternator.
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What three things must be synchronized before a three-phase AC generator can be connected to a bus that is being served by another generator?
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The voltage, the frequency, and the phase rotation of the generators.
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What must be done to reverse the direction of rotation of the armature of a DC electric motor?
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The current flow must be reversed through the armature or the field windings, but not through both of them.
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Does a series-wound DC motor have a high or a low starting torque?
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A high starting torque.
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Which aircraft electrical circuit does not normally contain a fuse or circuit breaker?
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The starter motor circuit.
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When removing a battery from an aircraft, which connection should be removed first?
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The ground connection must be disconnected first and connected last.
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What is meant by the effective voltage of sine wave alternating current?
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The value of the alternating current that is needed to produce the same amount of heat as this value of direct current.
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