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152 Cards in this Set
- Front
- Back
- 3rd side (hint)
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Why is stranded wire used rather than solid wire in most powerplant electrical systems? |
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
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Why are the wires in certain electrical installations twisted together?
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The magnetic fields of the wire 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 are insulated with high temperature insulation.
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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 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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Why must a switch be derated if it is used in a circuit controlling a DC electric motor?
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Because of the 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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When the voltage rises above the regulated value, the relay inserts a resistor in the generator field circuit.
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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.
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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.
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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
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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.
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What is a starter–generator that is used with many of the smaller gas turbine engines?
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Generator that serves as a starter for turbine engine. When the engine is running it acts as a generator.
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When should aircraft wiring be installed in a conduit?
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When the wiring passes through an area in the aircraft where open wiring could likely be damaged.
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When should the brushes in a starter motor be replaced?
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When they have worn to half of their original length
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How is the direction of rotation of a DC electric motor reversed?
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Reverse the polarity of the armature or the field, but not both
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What is used as the rectifier to produce direct current in a DC alternator?
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Six solid–state diodes
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Is a starter motor series–wound or shunt–wound?
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Series wound
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What are two ways wires can be attached to the pins in a cannon plug?
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By soldering the wires into pots on the pins
By crimping tapered pins onto the wires |
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What must be done to a DC generator, after it has been overhauled, before it can produce electricity?
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The field must be flashed
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Why is it not necessary to flash the field of a DC alternator after it has been overhauled?
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An alternators field is already excited by battery current
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What is meant by a trip–free circuit breaker?
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A circuit breaker that opens as long as the fault exists, regardless of the position of the operating handle.
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Which way should the toggle of a switch that controls the propeller pitch move to place the propeller in low pitch (high RPM)?
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Forward
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Why are protective covers placed over some switches in an aircraft electrical circuit?
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To prevent the switch from being inadvertently actuated
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What is meant by the viscosity of engine lubricating oil?
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the oils resistance to flow
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What is meant by a wet sump lubrication system?
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lubrication system in which the oil is carried inside the engine itself.
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What is meant by a dry sump lubrication system?
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lubrication system in which the oil is carried in a tank that is not a part of the engine.
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How is oil temperature controlled in an aircraft reciprocating engine?
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Oil is either directed through or around the oil cooler core to maintain temp.
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Is the oil temperature shown on the aircraft instrument panel the temperature of the oil entering the engine or of the oil leaving the engine?
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temperature of oil entering the engine.
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What is the purpose of oil dilution in a reciprocating engine?
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When very cold weather is anticipated, gasoline can be mixed with the lubricating oil before the engine is shut down. This reduces the viscosity of the oil and makes starting easier.
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What is the function of the hopper in the oil tanks used with some reciprocating engines?
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Hoppers are a part of the oil dilution system. Only the oil in the hopper is diluted.
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What happens to the gasoline that is used to dilute the oil in the crankcase of an aircraft reciprocating engine?
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When the engine is running and the oil is warm, the gasoline evaporates out of it.
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What is the purpose of the sludge plugs in the crankshaft of a reciprocating engine?
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They trap sludge that is in the oil and hold it until the engine is disassembled at overhaul.
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Which pump is the larger in a dry–sump lubricating system, the pressure pump or the scavenger pump?
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The scavenger pump is bigger
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Why do full–flow oil filters have a spring–operated bypass valve in them?
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In case the filter should plug up so it cannot pass any oil, the bypass valve will open and allow unfiltered oil to flow through the system.
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What is the function of a fuel–oil heat exchanger in the lubrication system of a turbojet engine?
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This allows heat from the oil to warm the fuel
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What kind of oil is used in most turbojet engines?
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Synthetic oil.
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Where are the last chance oil filters located in a turbojet engine?
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located just ahead of the nozzles that spray oil onto the bearings.
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Where is the oil tank in a dry–sump reciprocating engine vented?
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at the engine crankcase.
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What information must be displayed around the oil filler opening for a turbojet engine?
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The word "Oil" and the permissible oil designations, or references to the Airplane Flight Manual
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What is the function of the oil control rings on the piston of an aircraft reciprocating engine?
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They maintain the proper quantity of oil between the piston and the cylinder wall.
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What is meant by a spectrometric oil analysis?
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It is a program in which a sample of oil is taken from the engine at regular intervals and sent to a laboratory. A single sample is meaningless. There must be a series of samples taken at regular intervals to measure the change in the amounts of these metals.
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What indication would a pilot have if his oil supply was low?
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The oil temperature would be high and the oil pressure would be low.
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What is meant by a hot–tank lubrication system?
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A system in which the oil cooler is located in the pressure subsystem.
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What is meant by a cold–tank lubrication system?
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A system in which the oil cooler is located in the scavenge subsystem.
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What is straight mineral oil?
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A distillation of crude oil with no additives
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Crude oil: no adds |
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What is ashless dispersant (AD) oil?
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A mineral oil containing additives that disperse the contaminants throughout the oil so they will not clog oil passages.
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Mineral oil: adds to prevent clogging: no ash forming additives
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What is synthetic oil?
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Oil that is made by chemically changing the nature of an oil base to give it the needed characteristics.
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Chemically: base: needed characteristics
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Is automotive oil suitable for use in aircraft?
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No, automotive and aviation oils are formulated entirely different
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What is meant by a multiviscosity oil?
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Oil that increases in viscosity when it is hot and decreases viscosity when cold
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Viscosity index improver
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What are six functions of the oil in an engine?
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Reduces friction
Seals and cushions Removes heat Cleans inside the engine Protects against corrosion Performs hydraulic action |
S.c.r.r.p.p
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Where can you find the grade of engine oil specified for a particular aircraft?
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Aircraft Flight Manual or the Pilots Operating Handbook for the aircraft
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What components in a reciprocating–engine lube system must be inspected on a 100 hr or annual?
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Oil tank
oil strainer oil filter oil cooler oil pressure and temp gages entire engine for oil leaks |
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What two instruments show the condition of a reciprocating–engine lube system?
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Oil pressure gage
Oil temp gage |
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What must be done to an oil filter when it is removed from the engine?
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Cut open the filter element and examine to see the type and amount of contaminants
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What is the purpose of an air–oil separator, or deaerator, in a turbine engine oil tank?
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In normal operation, the oil picks some air and is swirled in the deaerator. The swirling action releases the air from the oil, and the air is used to pressurize the oil tank
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What type of oil quantity indicator is used in most aircraft engines?
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A dipstick that measures the quantity of oil in the tank or sump
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When should the engine oil quantity be checked on a turbine?
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As soon as practical after the engine is shut down
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Where is the oil temp measured on a recip engine?
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At the Pressure screen before the oil goes into the engine
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How is oil pressure regulated in an engine?
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A Pressure–relief valve set to the desired pressure sends all of the oil that caused excessive pressure back into the engine tank
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Why do engine manufactures recommend that engine lube oil be changed at specific intervals?
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Oil picks up contaminants and carries them through the engine where they can cause wear.
The oil becomes acidic and causes corrosion |
Contaminants/acidic
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What is the purpose of the restricted orifice in the line between the oil pressure gage and the engine?
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Helps dampen pulsations in oil pressure caused by the pump
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What is the main advantage of a magneto ignition system over a battery ignition system for an aircraft reciprocating engine?
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A magneto has its own source of electrical energy, and doesn't need a battery.
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What is the function of the capacitor in a magneto?
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The capacitor minimizes arcing at the breaker points
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What is the significance of the numbers on the distributor of an aircraft magneto?
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The sparking order of the magneto
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What happens in a magneto ignition system when the ignition switch is placed in the Off position?
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The primary circuit is connected to ground.
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What is the reason for having a low–tension ignition system on some aircraft?
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Low–tension magnetos are used on aircraft that fly at high altitudes where there is a problem with flashover
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What is the basic difference between a low–tension magneto and a high–tension magneto?
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The low–tension ignition system has only one coil in the magneto
A high–tension magneto produces high voltage in the magneto coil |
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What is meant by an All Weather spark plug?
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A sealed spark plug that has a grommet on the ignition lead
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What is meant by the reach of a spark plug?
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The length of the threads on the spark plug that screw into the cylinder head.
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What is the difference between a hot spark plug and a cold spark plug?
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A hot spark plug has a long path for the heat to travel between the nose core insulator. A cold spark plug, the heat has a shorter distance to travel. Cold plugs operate cooler
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What is checked when a magneto is internally timed?
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Adjusting the breaker points so they will open at the E–gap position
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Why is it important that the spark plugs be kept in numbered holes in a tray when they are removed from an engine?
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Spark plugs tell a good deal about the internal condition of the cylinders from which they were taken
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What is the purpose of staggered timing between the two magnetos on an aircraft engine?
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By using staggered timing, the flame caused by the two spark plugs will meet in the center of the piston.
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In what position should the ignition switch be placed when using a timing light on the magnetos?
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In the Both position.
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Why is it important that a torque wrench always be used when installing spark plugs in an aircraft engine?
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There is a possibility of a poor seal, and too tight can cause the insulation to crack.
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Why are pressurized magnetos used on most reciprocating–engine–powered aircraft that fly at high altitudes?
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Pressurized air is a better insulator than less dense air.
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What type of ignition system is used on most turbine engines?
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High–intensity, intermittent–duty, capacitor discharge ignition systems.
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What is meant by the E–gap in magneto timing?
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The E–gap position is when the primary current flowing in the magneto coil is the greatest.
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What kind of gage should be used to measure the electrode gap in aircraft spark plugs?
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A round wire gage.
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How many igniters are used in most turbine engines?
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Two
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What are two types of ignition systems used in turbine engines?
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High–voltage systems
low–voltage systems. |
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With which type of ignition system is a glow plug igniter used?
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A low–voltage system.
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How is the strength of the magnet in a magneto checked?
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The magneto is put on a test stand and rotated at a specified speed.
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In what position is the magnet in a magneto when the greatest change in flux density in the coil core takes place?
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It is a few degrees beyond its neutral position.
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In what position is the magnet in a magneto when the breaker points begin to open?
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In its E–gap position, just a few degrees beyond its neutral position.
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What malfunction in the ignition system would cause an aircraft reciprocating engine to continue to run after the ignition switch is placed in the Off position?
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The ignition switch is not grounding the magneto primary circuit.
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What turns on the autoignition system in a turbo–prop engine?
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A torque pressure switch
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What kind of equipment is used to test an ignition harness for a recip enigne?
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electrical leak detector
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What kind of electric starting system is used on many of the smaller turbine engines?
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Starter–generator
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What happens when the start switch for a turbine with a starter–generator is placed in the START position?
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a. Current flows actuates the ignition exciter
b. Current flows through the starter generator and rotates the engine until it starts |
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What is indicated if the starter relay chatters rather than locks in, when the start switch is placed in the START position?
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Battery voltage is too low
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Why are air–turbine starters superior to electric starters for large turbine engines?
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They are light weight for the torque they produce
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Where does an air–turbine starter get its air for starting the engines on a jet transport airplane?
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APU, GPU or from a running engine
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What is the purpose of the shear section in an air–turbine drive shaft?
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If the engine drives the starter to a speed higher than its design speed, the shear section will break and disconnect the starter from the engine
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What prevents too high an air pressure from overspeeding an air–turbine starter?
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Air shutoff valve
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Where does an air–turbine starter get its lubricating oil?
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It has a self–contained lube system with the oil held in the starter housing
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What device in an air–turbine starter warns a technician it there are any metal chips or particles in the oil?
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Magnetic chip detectors
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Where does the fuel metering system of a turbine engine discharge its fuel?
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through spray nozzles into the combustion chambers.
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What is adjusted when the fuel control unit of a turbine engine is trimmed?
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idle speed and maximum–thrust
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What are two locations water may be injected into a turbine engine?
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At the compressor inlet and at the inlet to the diffuser
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What is meant by a duplex nozzle in a turbine engine fuel metering system?
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A duplex fuel nozzle is one that has two fuel discharge passages.
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Does the fuel–air mixture provided by a float carburetor become richer or leaner as the aircraft goes up in altitude?
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If the mixture is not adjusted, it will become richer as the aircraft gains in altitude.
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Does the fuel–air mixture provided by a float carburetor become richer or leaner when carburetor heat is applied?
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The mixture becomes richer when carburetor heat is applied.
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What would happen to the fuel–air mixture ratio in a float carburetor if the main air bleed were to become plugged?
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The mixture would become excessively rich.
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How does the automatic mixture control in a pressure carburetor keep the fuel–air mixture constant as the aircraft changes altitude?
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It automatically increases or decreases the air metering force.
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Why must the diaphragms of a pressure carburetor be soaked before the carburetor is ready for flight?
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restores them to the condition of flexibility that they had when the carburetor was calibrated.
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How does the exhaust gas temperature of a reciprocating engine tell anything about the fuel–air mixture being burned by the engine?
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a mixture in which all of the the fuel–air mixture are burned produces the highest exhaust gas temperature.
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What two things are adjusted when adjusting the idling of a reciprocating engine?
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The throttle stop and the idle mixture control
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What is the significance of the letters that are stamped on the flats of a fuel injection nozzle?
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The letters designate the size of the orifice in the injector nozzle.
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What is the function of the economizer system in an aircraft engine carburetor?
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allows the engine to operate with an economically lean mixture for all conditions other than full power.
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In what position is the mixture control placed for starting an engine that is equipped with a pressure carburetor?
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In the Idle Cutoff position.
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In what position is the carburetor heat control placed when starting an aircraft engine?
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In the Cold position.
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Where is the fuel from a continuous–flow fuel injection system discharged?
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It is discharged through injector nozzles screwed into the cylinder heads
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In which direction relative to the wind should a turbine–powered aircraft be positioned when the fuel control is being trimmed?
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If the wind velocity is less than 10 miles per hour, it can be faced in any direction. If the wind velocity is between 10 and 25 MPH, it should be trimmed facing into the wind. do not trim if more that 25mph
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What engine parameters are sensed by the fuel control unit of a turbine engine?
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Engine RPM, inlet air pressure, compressor discharge pressure, burner can pressure, and inlet air temperature.
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When does the acceleration system operate on an aircraft carburetor?
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When the throttle is suddenly opened.
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What is meant by trimming a turbine engine?
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Adjusting the fuel control for the proper specific gravity of the fuel and for the proper idle and full throttle RPM
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What are two types of electronic fuel controls for turbine engines?
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Supervisory Electronic Engine Control and Full–Authority Digital Electronic Control
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What is a FADEC?
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Full–Authority Digital Electronic Control
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Does a turbine engine controlled by a FADEC require manual trimming?
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No, this is done by the FADEC
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When should a turbine engine be retrimmed?
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Any time there is a decrease in engine thrust, and after any maintenance that the manufacture specifies as requiring retrimming
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Are the instruments installed in a aircraft suitable for use when trimming a turbine engine?
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No, a special analyzer/trimmer such as a JetCal should be used
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What specifications are used to trim a turbine engine?
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the data on the engines trim plug
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Where should ambient temp be measured when trimming?
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In a shaded area near the engine inlet
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What is the purpose of the bypass valve in an engine–driven fuel pump?
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The bypass valve allows fuel to flow around the pump for starting and for emergency operation if the pump should fail.
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On which side of the firewall is the engine fuel shutoff valve located?
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The shutoff valve must be on the opposite side of the engine.
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What are three purposes for the boost pumps in an aircraft fuel system?
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To provide fuel pressure for starting the engine, to pressurize the fuel lines to prevent vapor lock, and to transfer fuel from one tank to another.
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What kind of boost pump is used in most aircraft fuel systems?
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Electrically operated centrifugal pumps.
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Where does an engine–driven fuel pump direct the excess fuel from its pressure relief valve?
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Back to the inlet side of the pump.
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What causes a vapor lock in an aircraft fuel system?
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when the fuel changes from liquid to a gas in the fuel delivery system. cause by the fuel evaporating from heat
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What is done in most aircraft fuel systems to prevent vapor lock?
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Boost pumps in the fuel tank pressurize the fuel in the lines and force the fuel into the fuel delivery system.
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What is meant by a compensated relief valve in an engine–driven fuel pump?
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A pressure relief valve that is acted upon by a diaphragm as well as a spring.
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What is the purpose of the pressurizing and dump valve in the fuel system for a turbine engine?
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When the engine is shut down, the dump valve dumps all of the fuel from the manifold.
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What should be done to an aircraft reciprocating engine if it has been operated on turbine engine fuel?
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all of the cylinders should be inspected with a borescope. The oil should be drained and the filters carefully examined.
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What are the two basic types of turbine engine fuel?
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Jet A
Jet B |
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Why do some turbine engine fuel systems incorporate a fuel heater?
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The fuel heater keeps ice crystals from forming in the fuel
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What are two reasons Prist is used in turbine engine fuel?
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Prist is an antifreeze agent that is added to the fuel. It also kills the microbial growth in fuel tanks.
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Why do some aircraft fuel filters have a built–in relief valve?
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This relief valve will open and allow unfiltered fuel to flow to the fuel control device if the filter should become plugged with ice or other contaminants.
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What is meant by a compensated fuel pump?
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maintains the fuel pressure a specific amount above ambient air pressure
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What would likely cause a recip equipped with a float carb to hesitate momentarily when the throttle is rapidly advanced from idle to full power?
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Malfunctioning accelerator pump
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Why do aircraft fuel metering systems for recip have mixture controls?
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The mixture control allows the fuel to be decreased or increased due to altitude
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What are the two types of fuel injection system used on modern recips?
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TCM and Bendix systems
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What is used in the TCM fuel injection system to control the amount of fuel sent to the nozzles?
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Engine speed determines the injector pump output pressure.
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What is used in the Bendix system to control the amount of fuel sent to the nozzles?
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Mass of the air entering the engine
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Where are the fuel strainers normally located in an aircraft fuel system?
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the tank outlet, located at the lowest point in the system, and strainers in the carb or fuel injection system
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What are two types of fuel heaters used in a jet transport aircraft?
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Air fuel and oil fuel
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What kind of fuel boost pumps are normally installed inside the fuel tanks?
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Centrifugal pumps |
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