DGCA & EASA Module 15 : Part-13 Engine Starting and Ignition Systems Question

DGCA & EASA Module 15 : Part-13 Engine Starting and Ignition Systems Question-Answer

1. In the H.E.I.U. the discharge resistors.

A. allows the capacitors to discharge when the unit is switched off.

B. allows sufficient voltage to be stored to provide relight facilities up to 55,000 ft.

C. protects the unit from excessive voltages.

Ans : allows the capacitors to discharge when the unit is switched off.

Explanation: NIL.

2. In the H.E.I.U. the choke.

A. prolongs the life of the plug.

B. protects the unit from excessive high voltages.

C. prolongs the discharge.

Ans : prolongs the discharge.

Explanation: NIL.

3. In an electrical starting system, the slow start resistor is short circuited by the.

A. centrifugal Switch.

B. time switch.

C. overspeed switch.

Ans : centrifugal Switch.

Explanation: NIL.

4. The advantage of an air starter system is.

A. it provides a more rapid start.

B. it is light, simple and economical.

C. there is no risk of engine fire during starting.

Ans : it is light, simple and economical.

Explanation: Jeppesen A&P Technician Powerplant Book Page 8-49 'Air starters weigh about one-fifth the wieght of a comparable electric starter. This gives air turbine starters a high power-to-wieght ratio. because of this, pneumatic starters are used almost exclusively on commercial jet aircraft.

5. An advantage of a gas turbine starter is.

A. it provide high power for low weight.

B. it does not require external connections.

C. it uses a low volatile fuel.

Ans : it provide high power for low weight.

Explanation: NIL.

6. If the engine fails to light-up, the starter cycle is canceled by.

A. a centrifugal switch.

B. a low pressure relay.

C. a time switch.

Ans : a time switch.

Explanation: NIL.

7. For starting the engine, the H.P cock should be initially.

A. in a position which depends on the fuel system.

B. open.

C. closed.

Ans : closed.

Explanation: NIL.

8. On light up, the gas temperature will.

A. rise slowly.

B. rise rapidly, then fall as RPM increases to idle.

C. rise rapidly.

Ans : rise rapidly, then fall as RPM increases to idle.

Explanation: NIL.

9. Self sustaining RPM means that.

A. The engine can accelerate to full power in under 5 seconds.

B. There is sufficient power for ground maneuvering.

C. The engine will run independently of external help.

Ans : The engine will run independently of external help.

Explanation: NIL.

10. A 'hot start' with excessive temperatures may be caused by.

A. wrong grade of fuel.

B. throttle partly open.

C. high electrical power supply.

Ans : throttle partly open.

Explanation: NIL.

11. A dry motoring cycle would be required to.

A. clear the engine after a wet start.

B. check engine run down time.

C. check the operation of the igniters.

Ans : clear the engine after a wet start.

Explanation: NIL.

12. What type of turbine blade is most commonly used in air starter motors?.

A. Reaction.

B. Impulse.

C. Impulse-reaction.

Ans : Impulse.

Explanation: NIL.

13. Ignitor plugs are cleaned by.

A. compressed air and brushing lightly with soft brush.

B. light sand blasting.

C. steel wool.

Ans : compressed air and brushing lightly with soft brush.

Explanation: Jepperson Gas Turbine Powerplants Page 11-11 refers.

14. An H.E.I.U works by.

A. a discharging capacitor.

B. ac busbar.

C. a contact breaker.

Ans : a discharging capacitor.

Explanation: Jepperson Gas Turbine Powerplants Page 11-5 refers.

15. When is ignition used?.

A. For relight and start up.

B. For continuous relight.

C. At high altitudes.

Ans : For relight and start up.

Explanation: Rolls Royce The Jet Engine Page 127 Refers.

16. An ignitor plug for a large gas turbine takes the form of a.

A. glow' plug.

B. sparking plug.

C. surface discharge plug.

Ans : surface discharge plug.

Explanation: Rolls Royce The Jet Engine Page 131 Refers.

17. The spark in the High Energy igniter is supplied by.

A. a capacitor.

B. a contact circuit breaker.

C. the AC busbar.

Ans : a capacitor.

Explanation: Jeppesen Gas Turbine Powerplant Page11-4 refers.

18. Self sustaining speed is.

A. V1 speed.

B. the RPM at which the engine continues without external assistance.

C. take off velocity.

Ans : the RPM at which the engine continues without external assistance.

Explanation: After the starter has cut out and the RPM and TGT have stabilised.

19. During normal running conditions.

A. combustion is intermittently supported by ignition.

B. combustion is self supporting

C. combustion is continuously supported by ignition.

Ans : combustion is self supporting

Explanation: Rolls Royce The Jet Engine page 37 refers.

20. High energy ignition is required because of the.

A. high flash point of the fuel.

B. absorbed moisture content.

C. low flash point of the fuel.

Ans : high flash point of the fuel.

Explanation: Jeppesen Gas Turbine Powerplants Page 7-1 refers.

21. In the H.E.I.U. the discharge resistors.

A. allow sufficient voltage to be stored to provide relight facilities up to 55,000 ft.

B. allow the capacitors to discharge when the unit is switched off.

C. protect the unit from excessive voltages.

Ans : allow the capacitors to discharge when the unit is switched off.

Explanation: Rolls Royce The Jet Engine page 129 refers

22. The rate of discharge of a H.E.I.U. is.

A. 4 discharges per revolution.

B. 60 - 100 per second.

C. 60 - 100 per minute.

Ans : 60 - 100 per minute.

Explanation: NIL.

23. Why do turbine engine ignition systems require high energy?.

A. Because the applied voltage is much greater.

B. To ignite the fuel under conditions of high altitude and high temperatures.

C. To ignite the fuel under conditions of high altitude and low temperatures.

Ans : To ignite the fuel under conditions of high altitude and low temperatures.

Explanation: Jeppesen A&P Technician Propulsion Textbook 8-102.

24. The type of ignition system used on most turbine aircraft engines is.

A. low tension.

B. capacitor discharge.

C. high resistance.

Ans : capacitor discharge.

Explanation: Jeppesen A&P Technician Propulsion Textbook 8-102.

25. A safety feature usually employed in pneumatic starters that is used to prevent the starter from reaching burst speed if inlet air does not terminate on schedule is the.

A. stator nozzle design that chokes airflow and stabilizes turbine wheel speed.

B. drive shaft shear point.

C. spring coupling release.

Ans : stator nozzle design that chokes airflow and stabilizes turbine wheel speed.

Explanation: Jeppesen A&P Technician Propulsion Textbook 8-49.

26. 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 the.

A. spring coupling release.

B. drive shaft shear point.

C. flyweight cutout switch.

Ans : flyweight cutout switch.

Explanation: Jeppesen A&P Technician Propulsion Textbook 8-49.

Click Here For : DGCA & EASA Module 15 : Part-14 Engine Indication Systems Question

27. Airflow to the pneumatic starter from a ground unit is normally prevented from causing starter overspeed during engine start by.

A. a preset timed cutoff of the airflow at the source.

B. stator nozzle design that chokes airflow and stabilizes turbine wheel speed speed.

C. activation of a flyweight cutout switch.

Ans : activation of a flyweight cutout switch.

Explanation: Jeppesen A&P Technician Propulsion Textbook 8-49.

28. Air turbine starters are generally designed so that reduction gear distress or damage may be detected by.

A. inspection of a magnetic chip detector.

B. characteristic sounds from the starter assembly during engine start.

C. breakage of a shear section on the starter drive shaft.

Ans : inspection of a magnetic chip detector.

Explanation: Jeppesen A&P Technician Propulsion Textbook 8-51.

29. Inspection of pneumatic starters by maintenance technicians usually includes checking the.

A. stator and rotor blades for FOD.

B. oil level and magnetic drain plug condition.

C. rotor alignment.

Ans : oil level and magnetic drain plug condition.

Explanation: Jeppesen A&P Technician Propulsion Textbook 8-51.

30. Pneumatic starters are usually designed with what types of airflow impingement systems?.

A. Radial inward flow turbine and axial-flow turbine.

B. Centrifugal compressor and axial-flow compressor.

C. Double entry centrifugal outward flow and axial-flow turbines.

Ans : Radial inward flow turbine and axial-flow turbine.

Explanation: Jeppesen A&P Technician Propulsion Textbook 8-49.

31. A clicking sound heard at engine coast-down in a pneumatic starter incorporating a sprag clutch ratchet assembly is an indication of.

A. gear tooth and/or pawl damage.

B. one or more broken pawl springs.

C. the pawls re-contacting and riding on the ratchet gear.

Ans : the pawls re-contacting and riding on the ratchet gear.

Explanation: Jeppesen A&P Technician Propulsion Textbook 8-50.

32. The primary advantage of pneumatic (air turbine) starters over comparable electric starters for turbine engines is.

A. high power-to-weight ratio.

B. reduction gearing not required.

C. a decreased fire hazard.

Ans : high power-to-weight ratio.

Explanation: NIL.

33. The purpose of an under current relay in a starter-generator system is to.

A. keep current flow to the starter-generator under the circuit capacity maximum.

B. disconnect power from the starter-generator and ignition when sufficient engine speed is reached.

C. provide a backup for the starter relay.

Ans : disconnect power from the starter-generator and ignition when sufficient engine speed is reached.

Explanation: Jeppesen A&P Technician Propulsion Textbook 8-46.

34. How does the ignition system of a gas turbine engine differ from that of a reciprocating engine?.

A. Magneto to engine timing is not critical.

B. One igniter plug is used in each combustion chamber.

C. A high energy spark is required for ignition.

Ans : A high energy spark is required for ignition.

Explanation: Jeppesen A&P Technician Propulsion Textbook 8-102.

35. In a gas turbine engine D.C capacitor discharge ignition system, where are the high voltage pulses formed?.

A. At the rectifier.

B. At the triggering transformer.

C. At the breaker.

Ans : At the triggering transformer.

Explanation: Jeppesen A&P Technician Propulsion Textbook 8-103.

36. Igniter plugs used in turbine engines are subjected to high intensity spark discharges and yet they have a long service life because they.

A. operate at much lower temperatures.

B. are not placed directly into the combustion chamber.

C. do not require continuous operation.

Ans : do not require continuous operation.

Explanation: Jeppesen A&P Technician Propulsion Textbook 8-105.

37. Great caution should be exercised in handling damaged hermetically sealed turbine engine igniter transformer units because.

A. some contain toxic chemicals.

B. some contain radioactive material.

C. compounds in the unit may become a fire or explosion hazard when exposed to the air.

Ans : some contain radioactive material.

Explanation: Jeppesen A&P Technician Propulsion Textbook 8-106.

38. 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.

A. disconnected from the power supply circuit.

B. the transformer exciter input lead is disconnected and the center electrode grounded to the engine after disconnecting the igniter lead from the plug and waiting the prescribed time.

C. 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.

Ans : 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.

Explanation: NIL.

39. What is the first engine instrument indication of a successful start of a turbine engine?.

A. A rise in the engine fuel flow.

B. A rise in oil pressure.

C. A rise in the exhaust gas temperature.

Ans : A rise in the exhaust gas temperature.

Explanation: NIL.

40. H.E.I.U ignitor plugs receive their electrical supply from.

A. discharge inductor.

B. starter system electrical circuit.

C. discharge capacitor.

Ans : discharge capacitor.

Explanation: Rolls Royce The Jet Engine Page 129.

41. An H.E.I.U is rated in.

A. Joules.

B. Watts.

C. Amps.

Ans : Joules.

Explanation: Jeppesen Aircraft Gas Turbines Powerplant Page 11-5 to 11-7 refers.

42. A glow plug operates.

A. manually.

B. by heat action.

C. electrically.

Ans : by heat action.

Explanation: The extreme heat of the plug ignites the fuel. It is powered by electricity. See Jeppesen

Aircraft Gas Turbines page 11-9.

43. The resistor in a D.C. starter motor.

A. prevents over speed.

B. prevents current surge when motor is at low rpm.

C. used when D.C. motor fails.

Ans : prevents current surge when motor is at low rpm.

Explanation: Rolls Royce The Jet Engine page 122 refers.

44. Where does the high voltage type turbine ignition receive its voltage pulse from?.

A. Primary windings.

B. Rectifier.

C. Trigger transformer.

Ans : Primary windings.

Explanation: Rolls Royce the jet engine Fig 11-12 shows an AC system. this uses a transformer to generate the high voltage at the discharge gap.

45. On a gas turbine engine DC starting circuit, if there is an open circuit on the contact of the over speed relay.

A. starter motor will stop only when starter switch selected off.

B. starter motor will continue to run for 30 sec and then stop.

C. no power supply is connected to the starter motor.

Ans : no power supply is connected to the starter motor.

Explanation: Refer Fig 11-3 Rolls Royce The Jet engine. The main relay cannot close if the overspeed relay is open.

46. The field of the D.C. starter motor used on gas turbine engine is.

A. series only.

B. shunt or compound.

C. series or compound.

Ans : series or compound.

Explanation: Aircraft electrical systems E.H.J Pallett 3rd edition page 154 refers.

47. When 'blow out' is selected on the Gas Turbine Engine starting circuit.

A. the starter motor is stopped when starter switch selected off or when the timer switch cuts out.

B. the over-speed relay will de-energise the starter circuit.

C. ignition is continuously on.

Ans : the starter motor is stopped when starter switch selected off or when the timer switch cuts out.

Explanation: Refer Fig 11-3 Rolls Royce The Jet Engine. The blow out circuit is used to blow out any jet pipe fire. In this mode there is no ignition or fuel hence the starter cannot overspeed.

48. After an unsuccessful start of an engine.

A. the engine has to be left for some time before another start.

B. unburnt fuel can be drained from fuel drainage lines.

C. unburnt fuel can be evacuated by motoring the engine with H.P cock closed.

Ans : unburnt fuel can be evacuated by motoring the engine with H.P cock closed.

Explanation: On normal shutdowns combustors and fuel manifolds are drained through the drain manifold. After an unsuccessful start there will be fuel throughout the hot section. Hence a dry run is needed to purge the engine.

49. A glow plug may be used in place of a spark plug on.

A. low temperature engines.

B. large engines.

C. small engines.

Ans : small engines.

Explanation: Jeppesen Aircraft Gas Turbine Powerplants Page 11-9 refers to the PW PT6 as an example of a smaller engine.

50. When an engine being started by an air starter reaches self sustaining speed.

A. the motor is disconnected by the flyweight cut out switch.

B. the starter valve is disconnected by the fly weight cut-out switch in the air starter.

C. the motor is disconnected by the pilot.

Ans : the starter valve is disconnected by the fly weight cut-out switch in the air starter.

Explanation: Jeppesen Aircraft Gas Turbine Powerplants Page 10-9 refers.

51. When reconnecting a H.E.I.U , which cable must be reconnected first?.

A. It makes no difference.

B. L.T before H.T.

C. H.T before L.T.

Ans : H.T before L.T.

Explanation: This is the reverse of disconnecting, when L.T is isolated and then disconnected first.

52. An aircraft flying through heavy rain may use, as a precaution.

A. airframe deicing.

B. engine intake deicing.

C. continuous ignition.

Ans : continuous ignition.

Explanation: Continuous ignition is used in case of flame out caused by the inclement weather.

53. The starter light is on during a start cycle (low voltage electrical starter).

A. Indicates electrical power is flowing to the starter.

B. If the light stays on after 30 seconds action is required.

C. This is normal for 30 seconds, take no action.

Ans : If the light stays on after 30 seconds action is required.

Explanation: See the Rolls Royce Jet engine low voltage starter system on page 123. The indicator light indicates power to the igniter. The Full current time switch cuts out the circuit after a period of time.

54. A D.C starter motor disconnects due to.

A. current decreasing switching off an overspeed relay.

B. current increasing switching off an overspeed relay.

C. a centrifugal switch that acts like an overspeed relay.

Ans : current decreasing switching off an overspeed relay.

Explanation: Same starter circuit reference as above. As the starter accelerates drawn current reduces and causes the overspeed relay to drop out.

55. What is the purpose of the current limiting resistor in a starter circuit?.

A. To prevent the starter from over speeding in the final phase of starting.

B. To provide overall control of the the speed of the starter.

C. To prevent an initial current surge.

Ans : To prevent an initial current surge.

Explanation: The starter motor is protected from excessive current until the timer shorts out the resistor. See RR the jet engine page 123.

56. On a low energy dual ignition system (<3 joules), if a relight is necessary.

A. it occurs automatically.

B. the pilot selects both ignitors.

C. the pilot selects one of the two ignitors.

Ans : the pilot selects both ignitors.

Explanation: Normal low/high systems have a choice of low or high energy ignition with high being used for relight. In these systems the pilot can choose 1, 2 or both.


Click Here For : DGCA & EASA Module 15 : Part-14 Engine Indication Systems Question