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Ignition and Starting Systems

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12 Shop (Powerplant) Quiz on Ignition and Starting Systems, created by jocelyn2145 on 07/11/2015.
jocelyn2145
Quiz by jocelyn2145, updated more than 1 year ago
jocelyn2145
Created by jocelyn2145 about 10 years ago
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Resource summary

Question 1

Question
Why are high-tension ignition cables frequently routed from the distributors to the spark plugs in flexible metallic conduits?
Answer
  • To eliminate high altitude flashover.
  • To reduce the formation of corona and nitric oxide on the cable insulation.
  • To reduce the effect of the high-frequency electromagnetic waves emanated during operation.

Question 2

Question
In an aircraft ignition system, one of the functions of the capacitor is to
Answer
  • regulate the flow of current between the primary and secondary coil.
  • facilitate a more rapid collapse of the magnetic field in the primary coil.
  • stop the flow of magnetic lines of force when the points open.

Question 3

Question
When the switch is off in a battery ignition systems, the primary circuit is
Answer
  • grounded.
  • opened.
  • shorted.

Question 4

Question
The purpose of staggered ignition is to compensate for
Answer
  • short ignition harness.
  • rich/fuel air mixture around exhaust valve.
  • diluted fuel/air mixture around exhaust valve.

Question 5

Question
What is the difference between a low-tension and high-tension engine ignition system?
Answer
  • A low-tension system produces relatively low voltage at the spark plug as compared to a high-tension system.
  • A high-tension system is designed for high altitude aircraft, while a low-tension system is for low-to medium-altitude aircraft.
  • A low tension system uses a transformed coil near the spark plugs to boost voltage, while the high-tension system voltage is constant from the magneto to the spark plugs.

Question 6

Question
What test instrument could be used to test an ignition harness for suspected leakage?
Answer
  • A high tension lead tester.
  • A high voltage DC voltmeter.
  • A high amperage DC ammeter.

Question 7

Question
The capacitor-type ignition system is used almost universally on turbine engines primarily because of its high voltage and
Answer
  • low amperage.
  • long life.
  • high-heat intensity.

Question 8

Question
How does the ignition system of a gas turbine engine differ from that of a reciprocating engine?
Answer
  • One igniter plug is used in each combustion chamber.
  • Magneto-to-engine timing is not critical.
  • A high-energy spark is required for ignition.

Question 9

Question
In a turbine engine DC capacitor discharge ignition system, where are the high-voltage pulses formed?
Answer
  • At the breaker.
  • At the triggering transformer.
  • At the rectifier.

Question 10

Question
Why are turbine engine igniters less susceptible to fouling than reciprocating engines spark plugs?
Answer
  • The high-intensity spark cleans the igniter.
  • The frequency of the spark is less for igniters.
  • Turbine igniters operate at cooler temperatures.

Question 11

Question
The constrained-gap igniter plug used in some gas turbine engines operates at cooler temperature because
Answer
  • it projects into the combustion chamber.
  • the applied voltage is less.
  • the construction is such that the spark occurs beyond the face of the combustion chamber liner.

Question 12

Question
Generally, when removing a turbine engine igniter plug, in order to eliminate the possibility of the technician receiving a lethal shock, the ignition switch is turned off and
Answer
  • disconnected from the power supply circuit.
  • the igniter lead is disconnected from the plug and the center electrode grounded to the engine after disconnecting the transformer-exciter input lead and waiting the prescribed time.
  • the transformer-exciter input lead is disconnected and the center electrode grounded after disconnecting the igniter lead from the plug and waiting the prescribed time.

Question 13

Question
Great caution should be exercised in handling damaged hermetically sealed turbine engine igniter transformer units because
Answer
  • compounds in the unit may become a fire or explosion hazard when exposed to the air.
  • some contain radioactive material.
  • some contain toxic chemicals.

Question 14

Question
Igniter plugs are subjected to high intensity spark discharges and yet they have a long service life because they
Answer
  • operate at much lower temperatures.
  • are not placed directly into the combustion chamber.
  • do not require continuous operation.

Question 15

Question
Sharp bends should be avoided in ignition leads primarily because
Answer
  • weak points may develop in the insulation through which high tension current can leak.
  • ignition lead wire conductor material is brittle and may break.
  • ignition lead shielding effectiveness will be reduced.

Question 16

Question
Which statement is correct regarding the ignition system of a turbine engine?
Answer
  • The system is normally de-energized as soon as the engine starts.
  • It is energized during the starting and warmup periods only.
  • The system generally includes a polar inductor-type magneto.

Question 17

Question
The type of ignition system used on most turbine aircraft engines is
Answer
  • high resistance.
  • low tension.
  • capacitor discharge.

Question 18

Question
Ignition check during engine runup indicates a slow drop in RPM. This is usually caused by
Answer
  • defective spark plugs.
  • a defective high-tension lead.
  • incorrect ignition timing or valve adjustment.

Question 19

Question
How does high-tension ignition shielding tend to reduce radio interference?
Answer
  • Prevents ignition flashover at high altitudes.
  • Reduces voltage drop in the transmission of high-tension current.
  • Receives and grounds high-frequency waves coming from the magneto and high-tension ignition leads.

Question 20

Question
Why do turbine engine ignition systems require high energy?
Answer
  • To ignite the fuel under conditions of high altitude and high temperatures.
  • Because the applied voltage is much greater.
  • To ignite the fuel under conditions of high altitude and low temperatures.

Question 21

Question
Which of the following are included in a typical turbine engine ignition system?
Answer
  • Two igniter plugs.
  • Two transformers.
  • One exciter unit.
  • Two intermediate ignition leads.
  • Two low tension igniter leads.
  • Two high tension igniter leads.

Question 22

Question
(Refer to figure 5.) With power applied to the bus bar, what wire supplies standby power to the starter relay contact?
Answer
  • 4.
  • 7.
  • 8.

Question 23

Question
(Refer to figure 5.) With power applied to the bus bar, what switch changes will allow the ignition exciters test switch to function?
Answer
  • Engine master switch, battery switch, and power lever switch.
  • Engine master switch, start switch, and test switch.
  • Engine master switch and ignition switch.

Question 24

Question
(Refer to figure 5.) The type of system depicted is capable of operating with
Answer
  • external power only.
  • either battery or external power.
  • battery power and external power simultaneously.

Question 25

Question
(Refer to figure 5.) If wire No. 8 is broken or disconnected after start rotation is initiated, and the power lever is advanced, the
Answer
  • starting sequence will continue normally.
  • starter will shut down, but the igniters will continue to fire.
  • starting sequence will discontinue.

Question 26

Question
(Refer to figure 5.) When an external power source is connected to the aircraft
Answer
  • the battery cannot be connected to the bus.
  • both battery power and external power are available to the bus.
  • the starter relay coil has a path to the ground.

Question 27

Question
The purpose of an under current relay in a starter-generator system is to
Answer
  • provide a backup for the starter relay.
  • disconnect power from the starter-generator and ignition when sufficient engine speed is reached.
  • keep current flow to the starter-generator under the circuit capacity maximum.

Question 28

Question
In a typical starter-generator system, under which of the following starting circumstances may it be necessary to use the start stop switch?
Answer
  • Hung start.
  • Hot start.
  • Contacts stick open.

Question 29

Question
(Refer to figure 5.) Which malfunctions will allow the igniters to operate hen tested but be inoperative during a starting attempt?
Answer
  • Conductor No. 10 broken.
  • Conductor No. 11 broken.
  • Ignition relay inoperative.
  • Conductor No. 12 broken.

Question 30

Question
(Refer to figure 5.) Which malfunctions will allow the igniters to operate normally during start but be inoperative when tested?
Answer
  • Conductor No. 14 broken.
  • Conductor No. 10 broken.
  • Conductor No. 15 broken.
  • Conductor No. 12 broken.

Question 31

Question
When using an electric starter motor, current usage
Answer
  • is highest at the start of motor rotation.
  • remains relatively constant throughout the starting cycle.
  • is highest just before starter cutoff (at highest RPM).

Question 32

Question
When using an electric starter motor, the current flow through it
Answer
  • is highest just before starter cutoff (at highest RPM).
  • remains relatively constant throughout the starting cycle.
  • is highest at the start of motor rotation.

Question 33

Question
The primary advantage of pneumatic (air turbine) starters over comparable electric starters for turbine engines is
Answer
  • a decreased fire hazard.
  • reduction gearing not required.
  • high power-to-weight ratio.

Question 34

Question
A clicking sound heard at engine coast-down in a pneumatic starter incorporating a sprag clutch ratchet assembly is an indication of
Answer
  • gear tooth and/or pawl damage.
  • one or more broken pawl springs.
  • the pawls recontacting and riding on the ratchet gear.

Question 35

Question
Pneumatic starters are usually designed with what types of airflow impingement systems?
Answer
  • Radial inward flow turbine and axial-flow turbine.
  • Centrifugal compressor and axial-flow compressor.
  • Double entry centrifugal outward flow and axial-flow turbines.

Question 36

Question
Inspection of pneumatic starters by maintenance technicians usually includes checking the
Answer
  • oil level and magnetic drain plug condition.
  • stator and rotor blades for FOD.
  • rotor alignment.

Question 37

Question
Air turbine starters are generally designed so that reduction gear stress or damage may be detected by
Answer
  • characteristic sounds from the starter assembly during engine start.
  • breakage of a shear section on the starter drive shaft.
  • inspection of a magnetic chip detector.

Question 38

Question
Airflow to the pneumatic starter from a ground unit is normally prevented from causing starter overspeed during engine start by
Answer
  • stator nozzle design that chokes airflow and stabilizes turbine wheel speed.
  • activation of a flyweight cutout switch.
  • a preset timed cutoff of the airflow at the source.

Question 39

Question
A safety feature usually employed in pneumatic starters that is used if the clutch does not release from the engine drive at the proper time during start is
Answer
  • flyweight cutout switch.
  • spring coupling release.
  • drive shaft shear point.

Question 40

Question
A safety feature usually employed in direct-cranking starters that is used to prevent the starter from reaching burst speed is the
Answer
  • drive shaft shear point.
  • stator nozzle design that chokes airflow and stabilizes turbine wheel speed.
  • spring coupling release.
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