Questions and Answers - Engine Instrument Systems | Aircraft Systems

Questions and Answers - Engine Instrument Systems

Multiple Choices Questions

1. Which unit most accurately indicates fuel consumption of a reciprocating engine?
a. Fuel flow meter.
b. Fuel pressure gauge.
c. Electronic fuel quantity indicator.

2. The fuel flowmeter used with a continuous-fuel injection system installed on an aircraft horizontally opposed reciprocating engine measures the fuel pressure drop across the
a. manifold valve.
b. fuel nozzles.
c. metering valve.

3. The principle fault in the pressure type fuel flowmeter indicating system, installed on a horizontally opposed continuous-flow fuel injected aircraft reciprocating engine, is that a plugged fuel injection nozzle will cause a
a.- normal operation indication.
b. lower than normal fuel flow indication.
c. higher than normal fuel flow indication.

4. Motor driven impeller and turbine fuel flow transmitters are designed to transmit data
a.- using aircraft electrical system power.
b. mechanically.
c. by fuel pressure.


5. The fuel-flow indicator rotor and needle for a motor impeller and turbine indicating system is driven by
a. an electrical signal.
b. direct coupling to the motor shaft.
c. a mechanical gear train.

6. On a twin-engine aircraft with fuel-injected reciprocating engines, one fuel-flow indicator reads considerably higher than the other in all engine operating configurations. What is the probable cause of this indication?
a. Carburetor icing.
b. One or more fuel nozzles are clogged.
c. Alternate air door stuck open.

7. The fuel-flow indication system used with many fuel injected opposed engine airplanes utilizes a measure of
a. fuel flow volume.
b. fuel pressure.
c. fuel flow mass.

8. In addition to fuel quantity, a computerized fuel system (CFS) with a totalizer-indicator provides indication of how many of the following?
1. Fuel flow rate.
2. Fuel used since reset or initial start-up.
3. Fuel time remaining at current power setting.
4. Fuel temperature.

a. TWO.
b. Three.
c. Four.

9. The fuel-flow indication data sent from motor driven impeller and turbine, and motorless type fuel flow transmitters is a measure of
a. fuel mass-flow.
b. fuel volume-flow.
c. engine burner pressure drop.

10. In an aircraft equipped with a pressure-drop type fuel flow indicating system, if one of the injector nozzles becomes restricted, this would cause a decrease in fuel flow with
a. a decreased fuel flow indication on the gauge.
b. an increased fuel flow indication on the gauge.
c. no change in fuel flow indication on the gauge.

11. A manifold pressure gauge is designed to
a.- maintain constant pressure in the intake manifold.
b. indicate differential pressure between the intake manifold and atmospheric pressure.
c. indicate absolute pressure in the intake manifold.

12. The purpose of an exhaust gas analyzer is to indicate the
a. brake specific fuel consumption.
b. fuel/air ratio being burned in the cylinders.
c. temperature of the exhaust gases in the exhaust manifold.

13. Which of the following types of electric motors are commonly used in electric tachometers?
a. Direct current, series-wound motors.
b. Synchronous motors.
c. Direct current. shunt-wound motors.

14. Where are the hot and cold junctions located in an engine cylinder temperature indicating system?
a. Both junctions are located at the instrument.
b. Both junctions are located at the cylinder.
c. The hot junction is located at the cylinder and the cold junction is located at the instrument.

15. Basically, the indicator of a tachometer system is responsive to change in
a. current flow.
b. frequency.
c. voltage.

16. Which statement is correct concerning a thermocouple type temperature indicating instrument system?
a. It is a balanced-type, variable resistor circuit.
b. It requires no external power source.
c. It usually contains a balancing circuit in the instrument case to prevent fluctuations of the system voltage from affecting the temperature reading.

17. Which statement is true regarding a thermocouple-type cylinder head temperature measuring system?
a. The resistance required for cylinder head temperature indicators is measured in farads.
b. The voltage output of a thermocouple system is determined by the temperature difference between the two ends of the thermocouple.
c. When the master switch is turned on, a thermocouple indicator will move off-scale to the low side.

18. What basic meter is used to indicate cylinder head temperature in most aircraft?
a. Electrodynamometer.
b. Galvanometer.
c. Thermocouple-type meter.

19. Which of the following is a primary engine instrument?
a. Tachometer.
b. Fuel flowmeter.
c. Airspeed indicator.

20. A complete break in the line between the manifold pressure gauge and the induction system will be indicated by the gauge registering
a. prevailing atmospheric pressure.
b. zero.
c. lower than normal for conditions prevailing.


21. Engine oil temperature gauges indicate the temperature of the oil
a. entering the oil cooler.
b. entering the engine.
c. in the oil storage tank.

22. Why do helicopters require a minimum of two synchronous tachometer systems?
a. One indicates engine RPM and the other tail rotor RPM.
b. One indicates main rotor RPM and the other tail rotor RPM.
c. One indicates engine RPM and the other main rotor RPM.

23. If the thermocouple leads were inadvertently crossed at installation, what would the cylinder temperature gauge pointer indicate?
a. Normal temperature for prevailing condition.
b. Moves off-scale on the zero side of the meter.
c. Moves off-scale on the high side of the meter.

24. A common type of electrically operated oil temperature gauge utilizes
a. either a wheatstone bridge or ratiometer circuit.
b. a thermocouple type circuit.
c. vapor pressure and pressure switches.

25. The indication on a thermocouple-type cylinder head temperature indicator is produced by
a. resistance changes in two dissimilar metals.
b. a difference in the voltage between two dissimilar metals.
c. a current generated by the temperature difference between dissimilar metal hot and cold junctions.

26.
( 1) Powerplant instrument range markings show whether the current state of powerplant operation is normal, acceptable for a limited time, or unauthorized.
(2) Powerplant instrument range markings are based on installed engine operating limits which may not exceed (but are not necessarily equal to) those limits shown on the engine Type Certificate Data Sheet.

Regarding the above statements,
a. both No. 1 and No.2 are true.
b. neither No. 1 nor No.2 is true.
c. only No. 1 is true.

27. Thermocouple leads
a. may be installed with either lead to either post of the indicator.
b. are designed for a specific installation and may not be altered.
c. may be repaired using solderless connectors.

28.
(1) Engine pressure ratio (EPR) is a ratio of the exhaust gas pressure to the engine inlet air pressure, and indicates the thrust produced.
(2) Engine pressure ratio (EPR) is a ratio of the exhaust gas pressure to the engine inlet air pressure, and indicates volumetric efficiency.

Regarding the above statements,
a. only No. 1 is true.
b. only No.2 is true.
c. both No. 1 and No.2 are true.

29. What unit in a tachometer system sends information to the indicator?
a. The three-phase ac generator.
b. The two-phase ac generator.
c. The synchronous motor.

30.
(1) Generally, when a turbine engine indicates high EGT for a particular EPR (when there is no significant damage), it means that the engine is out of trim.
(2) Some turbine-powered aircraft use RPM as the primary indicator of thrust produced, others use EPR as the primary indicator.

Regarding the above statements,
a. only No. 1 is true.
b. only No.2 is true.
c. both No. 1 and No.2 are true.

31. Engine pressure ratio is determined by
a.- multiplying engine inlet total pressure by turbine outlet total pressure.
b. dividing turbine outlet total pressure by engine inlet total pressure.
c. dividing engine inlet total pressure by turbine outlet total pressure.

32. Jet engine thermocouples are usually constructed of
a. chromel-alumel.
b. iron-constantan.
c. alumel-constantan.

33. Which of the following instrument discrepancies require replacement of the instrument?
1. Red line missing from glass.
2. Glass cracked.
3. Case paint chipped.
4. Will not zero out.
5. Pointer loose on shaft.
6. Mounting screw loose.
7. Leaking at line B nut.
8. Fogged.

a. 2, 3, 7, 8.
b. 2, 4, 5, 8.
c. 1, 2, 4, 7.

34. A Bourdon-tube instrument may be used to indicate
1. pressure.
2. temperature.
3. position.
4. quantity.

a. 1 and 2.
b. 1 and 3.
c. 2 and 4.

35. An indication of unregulated power changes that result in continual drift of manifold pressure indication on a turbosuper-charged aircraft engine is known as
a. Overshoot.
b. Waste gate fluctuation.
c. Bootstrapping.

36. Which of the following instrument conditions is acceptable and does NOT require immediate correction?
1. Red line missing.
2. Pointer loose on shaft.
3. Glass cracked.
4. Mounting screws loose.
5. Case paint chipped.
6. Leaking at line B nut.
7. Will not zero out.
8. Fogged.

a. 1.
b. 4.
c. 5.

37. A change in engine manifold pressure has a direct effect on the
a. piston displacement.
b. compression ratio.
c. mean effective cylinder pressure.

38. What instrument on a gas turbine engine should be monitored to minimize the possibility of a "hot" start?
a. RPM indicator.
b. Turbine inlet temperature.
c. Torquemeter.

39. In regard to using a turbine engine oil analysis program, which of the following is NOT true?
a.- Generally, an accurate trend forecast may bemade after an engine's first oil sample analysis.
b.- It is best to start an oil analysis program on an engine when it is new.
c. A successful oil analysis program should be run over an engine's total operating life so that normal trends can be established.

40. On an aircraft turbine engine, operating at a constant power, the application of engine anti-icing will result in
a. noticeable shift in EPR.
b. a false EPR reading.
c. an increase in EPR.


41. Engine pressure ratio is the total pressure ratio between the
a. aft end of the compressor and the aft end of the turbine.
b. front of the compressor and the rear of the turbine.
c. front of the engine inlet and the aft end of the compressor.

42. What would be the possible cause if a gas turbine engine has high exhaust gas temperature, high fuel flow, and low RPM at all engine power settings?
a. Fuel control out of adjustment.
b. Loose or corroded thermocouple probes for the EGT indicator.
c. Turbine damage or loss of turbine efficiency.

43. What is the primary purpose of the tachometer on an axial-compressor turbine engine?
a.- Monitor engine RPM during cruise conditions.
b.- It is the most accurate instrument for establishing thrust settings under all conditions.
c. Monitor engine RPM during starting and to indicate overspeed conditions.

44. The engine pressure ratio (EPR) indicator is a direct indication of
a. engine thrust being produced.
b. pressure ratio between the front and aft end of the compressor.
c. ratio of engine RPM to compressor pressure.

45. The exhaust gas temperature (EGT) indicator on a gas turbine engine provides a relative indication of the
a.- exhaust temperature.
b.- temperature of the exhaust gases as they pass the exhaust cone.
c. turbine inlet temperature.

46. What instrument indicates the thrust of a gas turbine engine?
a.- Exhaust gas temperature indicator.
b. Turbine inlet temperature indicator.
c. Engine pressure ratio indicator.

47. In a turbine engine, where is the turbine discharge pressure indicator sensor located?
a. At the aft end of the compressor section.
b.- At a location in the exhaust cone that is determined to be subjected to the highest pressures.
c. Immediately aft of the last turbine stage.

48. In what units are turbine engine tachometers calibrated?
a.- Percent of engine RPM.
b.- Actual engine RPM.
c. Percent of engine pressure ratio.

49. Instruments that provide readings of low or negative pressure, such as manifold pressure gauges, are usually what type?
a. Vane with calibrated spring.
b. Bourdon tube.
c. Diaphragm or bellows.

50. Instruments that measure relatively high fluid pressures, such as oil pressure gauges, are usually what type?
a.Vane with calibrated spring.
b. Bourdon tube.
c. Diaphragm or bellows.

51. The RPM indication of a synchronous ac motor tachometer is governed by the generator
a. voltage.
b. current.
c. frequency.

52. The EGT gauge used with reciprocating engines is primarily used to furnish temperature readings in order to
a. obtain the best mixture setting for fuel efficiency.
b. obtain the best mixture setting for engine cooling.
c. prevent engine overtemperature.

53. A red triangle, dot, or diamond mark on an engine instrument face or glass indicates
a. the maximum operating limit for all normal operations.
b. the maximum limit for high transients such as starting.
c. a restricted operating range.



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