Questions | Induction and Engine Airflow Systems

1. A method commonly used to prevent carburetor icing is to

1. preheat the intake air.
2. mix alcohol with the fuel.
3. electrically heat the venturi and throttle valve.

2. Carburetor icing is most severe at

1. air temperatures between 30 and 40F.
2. high altitudes.
3. low engine temperatures.

3. Into what part of a reciprocating engine induction system is deicing alcohol normally injected?

1. The supercharger or impeller section.
2. The airstream ahead of the carburetor.
3. The low-pressure area ahead of the throttle valve.

4. Carburetor icing on an engine equipped with a constant-speed propeller can be detected by

1. a decrease in power output with no change in manifold pressure or RPM.
2. an increase in manifold pressure with a constant RPM.
3. a decrease in manifold pressure with a constant RPM.

5. What part of an aircraft in flight will begin to accumulate ice before any other?

1. Wing leading edge.
2. Propeller spinner or dome.
3. Carburetor.

6. Carburetor icing may be eliminated by which of the following methods?

1. Alcohol spray and electrically heated induction duct.
2. Ethylene glycol spray and heated induction air.
3. Alcohol spray and heated induction air.

7. Where would a carburetor air heater be located in a fuel injection system?

1. At the air intake entrance.
2. None is required.
3. Between the air intake and the venturi.

8. An increase in manifold pressure when carburetor heat is applied indicates

1. ice was forming in the carburetor.
2. mixture was too lean.
3. overheating of cylinder heads.

9. During full power output of an unsupercharged engine equipped with a float-type carburetor, in which of the following areas will the highest pressure exist?

1. Venturi.
2. Intake manifold.
3. Carburetor air scoop.

10. The use of the carburetor air heater when it is not needed causes

1. a very lean mixture.
2. excessive increase in manifold pressure.
3. a decrease in power and possibly detonation.

11. As manifold pressure increases in a reciprocating engine, the

1. volume of air in the cylinder increases.
2. weight of the fuel/air charge decreases.
3. density of air in the cylinder increases.

12. Which of the following statements regarding volumetric efficiency of an engine is true?

1. The volumetric efficiency of an engine will remain the same regardless of the amount of throttle opening.
2. It is impossible to exceed 100 percent volumetric efficiency of any engine regardless of the type of supercharger used.
3. It is possible to exceed 100 percent volumetric efficiency of some engines by the use of superchargers of the proper type.

13. Bootstrapping of a turbocharged engine is indicated by

1. a overboost condition of the engine on takeoff.
2. a transient increase in engine power.
3. a maximum increase in manifold pressure.

14. Which of the following would be a factor in the failure of an engine to develop full power at takeoff?

1. Improper adjustment of carburetor heat valve control linkage.
2. Excessively rich setting on the idle mixture adjustment.
3. Failure of the economizer valve to remain closed at takeoff throttle setting.

15. If the turbocharger waste gate is completely closed,

1. none of the exhaust gases are directed through the turbine.
2. the turbocharger is in the OFF position.
3. all the exhaust gases are directed through the turbine.

16. Boost manifold pressure is generally considered to be any manifold pressure above

1. 14.7″ Hg.
2. 50″ Hg.
3. 30″ Hg.

17. What is the purpose of the density controller in a turbocharger system?

1. Limits the maximum manifold pressure that can be produced at other than full throttle conditions.
2. Limits the maximum manifold pressure that can be produced by the turbocharger at full throttle.
3. Maintains constant air velocity at the carburetor inlet.

18. What is the purpose of the rate-of-change controller in a turbocharger system?

1. Limits the maximum manifold pressure that can be produced by the turbocharger at full throttle conditions.
2. Controls the rate at which the turbocharger discharge pressure will increase.
3. Controls the position of the waste gate after the aircraft has reached its critical altitude.

19. What directly regulates the speed of a turbocharger?

1. Turbine.
2. Waste gate.
3. Throttle.

20. What is the purpose of a turbocharger system for a small reciprocating aircraft engine?

1. Compresses the air to hold the cabin pressure constant after the aircraft has reached its critical altitude.
2. Maintains constant air velocity in the intake manifold.
3. Compresses air to maintain manifold pressure constant from sea level to the critical altitude of the engine.

21. What are the three basic regulating components of a sea-level boosted turbocharger system?

1. Exhaust bypass assembly.
2. Compressor assembly.
3. Pump and bearing casing.
4. Density controller.
5. Differential pressure controller.

1. 2, 3, 4.
2. 1, 4, 5.
3. 1, 2, 3.

22. The differential pressure controller in a turbocharger system

1. reduces bootstrapping during part-throttle operation.
2. positions the waste gate valve for maximum power.
3. provides a constant fuel-to-air ratio.

23. The purpose of a sonic venturi on a turbocharged engine is to

1. limit the amount of air that can flow from the turbocharger into the cabin for pressurization.
2. increase the amount of air that can flow from the turbocharger into the cabin for pressurization.
3. increase the velocity of the fuel/air charge.

24. What i s used to drive a supercharger?

1. Exhaust gasses.
2. Gear train from the crankshaft.
3. Belt drive through a pulley arrangement.

25. The purpose of a bellmouth compressor inlet is to

1. provide an increased ram air effect at low airspeeds.
2. maximize the aerodynamic efficiency of the inlet.
3. provide an increased pressure drop in the inlet.

26. What method(s) is/are used to provide clean air to the engines of helicopters and turboprop airplanes that have particle (sand and ice) separators installed?

1. Positive and negative charged areas to attract and/or repel particulates out of the airflow.
2. Air/moisture separators, and “washing” the air clean utilizing water droplets.
3. Sharp airflow directional change to take advantage of inertia and/or centrifugal force, and filters or engine inlet screens.

27. The vortex dissipators installed on some turbine-powered aircraft to prevent engine FOD utilize

1. variable inlet guide vanes (IGV) and/or variable first stage fan blades.
2. variable geometry inlet ducts.
3. a stream of engine bleed air blown toward the ground ahead of the engine.

28. Vortex dissipator systems are generally activated by

1. a landing gear switch.
2. a fuel pressure switch anytime an engine is operating.
3. an engine inlet airflow sensor.

29. When an engine with a subsonic divergent type inlet duct is running in place at high speed on the ground, the air pressure within the inlet is

1. positive.
2. negative.
3. ambient.

30. What indications may shift when a turbofan engine anti-icing (bleed air) system is turned on?

1. Tachometer.
2. EGT.
3. EPR.

1. 1 and 2.
2. 1, 2, and 3.
3. 2 and 3.

31. The purpose of an engine/inlet anti-ice system is primarily to

1. remove ice from engine and/or inlet areas.
2. prevent ice formation in engine and/or inlet areas.
3. remove ice from engine and/or inlet areas and prevent ice formation in engine and/or inlet areas.

32. If carburetor or induction system icing is not present when carburetor heat is applied with no change in the throttle setting, the

1. mixture will become richer.
2. manifold pressure will increase.
3. engine RPM will increase.

33. When starting an engine equipped with a carburetor air heater, in what position should the heater be placed?

1. Hot.
2. Cold.
3. Neutral.

34. The application of carburetor heat during engine operation will

1. decrease the weight of the fuel/air charge.
2. decrease the volume of air in the cylinder.
3. increase the density of air in the cylinder.

35. The application of carburetor heat will have which of the following effects?

1. The manifold pressure will be increased.
2. The mixture will become leaner.
3. The mixture will become richer.

36. When operating an engine, the application of carburetor heat will have what effect on the fuel/air mixture?

1. Enriching the mixture because the AMC cannot make a correction for increased temperature.
2. Enriching the mixture until the AMC can make a compensation.
3. Leaning the mixture until the AMC can make a compensation.

37. In addition to causing accelerated wear, dust or sand ingested by a reciprocating engine may also cause

1. silicon fouling of spark plugs.
2. sludge formation.
3. acid formation.

38. In an airplane equipped with an alternate air system, if the main air duct air filter becomes blocked or clogged, the

1. system will automatically allow warm, unfiltered air to be drawn into the engine.
2. flow of air into the engine will be slowed or cut off unless alternate air is selected.
3. system will automatically allow warm, filtered alternate air to be drawn into the engine.

39. If a fire starts in the induction system during the engine starting procedure, what should the operator do?

1. Turn off the fuel switches to stop the fuel.
2. Continue cranking the engine.
3. Turn off all switches.

40. On small aircraft engines, fuel vaporization may be increased by

1. cooling the air before it enters the engine.
2. circulating the fuel and air mixture through passages in the oil sump.
3. heating the fuel before it enters the carburetor.

41. The action of a carburetor airscoop is to supply air to the carburetor, but it may also

1. cool the engine.
2. keep fuel lines cool and prevent vapor lock.
3. increase the pressure of the incoming air by ram effect.

42. A carburetor air pre-heater is not generally used on takeoff unless absolutely necessary because of the

1. loss of power and possible detonation.
2. possibility of induction system overboost.
3. inability of the engine to supply enough heat to make a significant difference.

Answer key