Why does the smoothness of operation of an engine increase with a greater number of cylinders?
The engine has larger counterbalance weights. The power impulses are spaced farther apart. The power impulses are spaced closer together.
The function of an APU air inlet plenum is to:
stabilize the pressure of the air before it enters the compressor. decrease the pressure of the air before entering the compressor. increase the velocity of the air before entering the compressor.
The device that controls the ratio of the fuel/air mixture to the cylinders is called a:
throttle valve. mixture control. metering jet.
What should be checked/changed to ensure the validity of a turbine engine performance check if an alternate fuel is to be used?
Fuel specific gravity setting. Maximum RPM adjustment. EPR gauge calibration.
What is the difference between a low tension and a high tension engine ignition system?
A low tension system uses a transformer coil near the spark plugs to boost voltage, while the high tension system voltage is constant from the magneto to the spark plugs. 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 produces relatively low voltage at the spark plug as compared to a high tension system.
Which of the following types of electric motors are commonly used in electric tachometers?
Direct current, series wound motors. Synchronous motors. Direct current, shunt-wound motors.
Which of the following should a mechanic consult to determine the maximum amount of cylinder cooling fin that could be removed when cracks are found?
AC 43.13-1A. Engine structure repair manual. Engine manufacturer's service or overhaul manual.
(1) Accumulation of contaminates in the compressor of a turbojet engine reduces aerodynamic efficiency of the blades.
(2) Two common methods for removing dirt deposits from turbojet engine compressor blades are a fluid wash and an abrasive grit blast.
Regarding the above statements, only No. 1 is true. only No. 2 is true. both No. 1 and No. 2 are true.
A characteristic of dyna focal engine mounts as applied to aircraft reciprocating engines is that the: shock mounts point toward the engine's center of gravity. engine attaches to the shock mounts at the engine's center of gravity. shock mounts eliminate the torsional flexing of the powerplant.
Which bearing is least likely to be a roller or ball bearing?
Master rod bearing (radial engine). Crankshaft main bearing (radial engine). Rocker arm bearing (overhead valve engine).
Which of the following functions requires the use of a propeller blade station?
Indexing blades. Propeller balancing. Measuring blade angle.
Which of the following factors helps determine the proper grade of oil to use in a particular engine?
Adequate lubrication in various attitudes of flight. Positive introduction of oil to the bearings. Operating speeds of bearings.
What normally prevents a Hartzell Compact propeller from going to feather when the engine is shut down on the ground?
A latch mechanism composed of springs and lock pins. Accumulator provided oil pressure. Propeller cylinder air pressure.
In order to reduce the possibility of ground shorting the circuits when the connectors are separated for maintenance, the AN and MS electrical connectors should be installed with the:
socket section on the ground side of the electrical circuit. pin section on the ground side of the electrical circuit. pin section on the positive side of the electrical circuit.
Which of the following would be a factor in the failure of an engine to develop full power at takeoff?
Failure of the economizer valve to remain closed at takeoff throttle setting. Excessively rich setting on the idle mixture adjustment. Improper adjustment of carburetor heat valve control linkage.
Carburetor icing on an engine equipped with a constant speed propeller can be detected by:
a decrease in power output with no change in manifold pressure or RPM. an increase in manifold pressure with a constant RPM. a decrease in manifold pressure with a constant RPM.
It is desirable that fuel lines have a gentle slope upward or downward and not have sharp curves or sharp rises and/or falls in order to:
prevent vapor lock. minimize the generation of static electricity by decreasing fluid friction in the lines. prevent stagnation or "pooling" of fuel in the fuel lines.
What will be the results of increasing the gap of the breaker points in a magneto?
Advance the spark and decrease its intensity. Retard the spark and increase its intensity. Retard the spark and decrease its intensity.
Select the correct statement concerning the idle system of a conventional float type carburetor.
The low pressure area created in the throat of the venturi pulls the fuel from the idle passage. Climatic conditions have very little effect on idle mixture requirements. The low pressure between the edges of the throttle valve and the throttle body pulls the fuel from the idle passage.
The actual power delivered to the propeller of an aircraft engine is called:
friction horsepower. brake horsepower. indicated horsepower.
If the RPM of an axial flow compressor remains constant, the angle of attack of the rotor blades can be changed by:
changing the compressor diameter. increasing the pressure ratio. changing the velocity of the airflow.
Airflow to the pneumatic starter from a ground unit is normally prevented from causing starter overspeed during engine start by:
a preset timed cutoff of the airflow at the source. stator nozzle design that chokes airflow and stabilizes turbine wheel speed. activation of a flyweight cutout switch.
In a typical starter-generator system, under which of the following starting circumstances may it be necessary to use the start stop switch?
Hung start. Hot start. Contacts stick open.
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. 5. 1. 4.
A defective primary capacitor in a magneto is indicated by:
a weak spark. burned and pitted breaker points. a fine grained frosted appearance of the breaker points.
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Where should the main fuel strainer be located in the aircraft fuel system?
At the lowest point in the fuel system. Downstream from the wobble pump check valve. At any point in the system lower than the carburetor strainer.
Using the following information, determine how many degrees the crankshaft will rotate with both the intake and exhaust valves seated.
Intake opens 15° BTDC.
Exhaust opens 70° BBDC.
Intake closes 45° ABDC.
Exhaust closes 10° ATDC. 25°. 290°. 245°.
(Refer to Figure 4 .) The following data concerning the installation of an electrical unit is known: current requirements for continuous operation - 11 amperes; measured cable length - 45 feet; system voltage - 28 volts (do not exceed 1 volt drop); cable in conduit and bundles. What is the minimum size copper electrical cable that may be selected? No. 14. No. 12. No. 10.
The abbreviation Pt7 used in turbine engine terminology means: the total inlet pressure. pressure and temperature at station No. 7. the total pressure at station No. 7.
How does the ignition system of a gas turbine engine differ from that of a reciprocating engine?
A high energy spark is required for ignition. One igniter plug is used in each combustion chamber. Magneto to engine timing is not critical.
Which of the following methods is used to straighten a bent aluminum propeller blade that is within repairable limits?
Either hot or cold straightening, depending on the location and severity of damage. Cold straightening only. Careful heating to accomplish straightening, followed by heat treatment to restore original strength.
Stator blades in the compressor section of an axial flow turbine engine:
decrease the air velocity and prevent swirling. straighten the airflow and accelerate it. increase the air velocity and prevent swirling.
A supervisory electronic engine control (EEC) is a system that receives engine operating information and:
adjusts a standard hydromechanical fuel control unit to obtain the most effective engine operation. controls engine operation according to ambient temperature, pressure, and humidity. develops the commands to various actuators to control engine parameters.
The operating temperature valve clearance of a radial engine as compared to cold valve clearance is:
less. the same. greater.
If the oil in the oil cooler core and annular jacket becomes congealed, what unit prevents damage to the cooler?
Surge protection valve. Airflow control valve. Oil pressure relief valve.
A continuous loop fire detector is what type of detector?
Spot detector. Rate of temperature rise detector. Overheat detector.
A carburetor air pre-heater is not generally used on takeoff unless absolutely necessary because of the:
possibility of induction system overboost. loss of power and possible detonation. inability of the engine to supply enough heat to make a significant difference.
One way that the automatic ignition relight systems are activated on gas turbine engines is by a:
drop in compressor discharge pressure. drop in fuel flow. sensing switch located in the tailpipe.
According to Federal Aviation Regulations, oil tank fillers on turbine engines must be marked with the word:
oil and the type and grade of oil specified by the manufacturer. oil and tank capacity. oil.
During ground check an engine is found to be rough running, the magneto drop is normal, and the manifold pressure is higher than normal for any given RPM. The trouble may be caused by:
several spark plugs fouled on different cylinders. a dead cylinder. a leak in the intake manifold.
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