When air passes through the venturi of a carburetor, what three changes occur?
Velocity increases, temperature increases, and pressure decreases. Velocity increases, temperature decreases, and pressure decreases. Velocity decreases, temperature increases, and pressure increases.
Instruments that measure relatively high fluid pressures, such as oil pressure gauges, are usually what type?
Diaphragm or bellows. Bourdon tube. Vane with calibrated spring.
An increase in manifold pressure when carburetor heat is applied indicates:
mixture was too lean. overheating of cylinder heads. ice was forming in the carburetor.
Ignition occurs at 28° BTDC on a certain four-stroke cycle engine, and the intake valve opens at 15° BTDC. How many degrees of crankshaft travel after ignition does the intake valve open? (Consider one cylinder only.).
707°. 373°. 347°.
(1) Most modern aircraft use circuit breakers rather than fuses to protect their electrical circuits.
(2) Federal Aviation Regulations Part 23 requires that all electrical circuits incorporate some form of circuit protective device.
Regarding the above statements,
only No. 1 is true. only No. 2 is true. both No. 1 and No. 2 are true.
Which fuel/air mixture will result in the highest engine temperature (all other factors remaining constant)?
A mixture leaner than a manual lean mixture of .060. A mixture leaner than a rich best power mixture of .085. A mixture richer than a full rich mixture of .087.
Propeller blade stations are measured from the:
index mark on the blade shank. hub centerline. blade base.
How does the aerodynamic twisting force affect operating propeller blades?
It tends to turn the blades to a low blade angle. It tends to bend the blades forward. It tends to turn the blades to a high blade angle.
An unsupercharged aircraft reciprocating engine, operated at full throttle from sea level, to 10,000 feet, provided the RPM is unchanged, will:
lose power due to the reduced density of the air drawn into the cylinders. produce constant power due to the same volume of air drawn into the cylinders. lose power due to the reduced volume of air drawn into the cylinders.
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.
In an axial flow turbine engine, compressor bleed air is sometimes used to aid in cooling the:
fuel. turbine, vanes, blades, and bearings. inlet guide vanes.
Where would a carburetor air heater be located in a fuel injection system?
None is required. At the air intake entrance. Between the air intake and the venturi.
Which of the following best describes the function of an altitude mixture control?
Regulates the air pressure in the venturi. Regulates the richness of the fuel/air charge entering the engine. Regulates the air pressure above the fuel in the float chamber.
Engine pressure ratio is the total pressure ratio between the:
aft end of the compressor and the aft end of the turbine. front of the engine inlet and the aft end of the compressor. front of the compressor and the rear of the turbine.
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.
What operational force causes the greatest stress on a propeller?
Aerodynamic twisting force. Centrifugal force. Thrust bending force.
Increased water vapor (higher relative humidity) in the incoming air to a reciprocating engine will normally result in which of the following?
A leaning effect on engines which use non automatic carburetors. Decreased engine power at a constant RPM and manifold pressure. Increased power output due to increased volumetric efficiency.
Maximum taper contact between crankshaft and propeller hub is determined by using:
a surface gauge. bearing blue color transfer. a micrometer.
Most engine propeller combinations have one or more critical ranges within which continuous operation is not permitted. Critical ranges are established to avoid:
severe propeller vibration. inefficient propeller pitch angles. low or negative thrust conditions.
The compressor stators in a gas turbine engine act as diffusers to:
increase the velocity and decrease the pressure of the gas. increase the velocity of the gas flow. decrease the velocity of the gas flow.
Manually feathering a hydromechanical propeller means to:
port governor oil pressure from the cylinder of the propeller. port governor oil pressure to the cylinder of the propeller. block governor oil pressure to the cylinder of the propeller.
What test instrument could be used to test an ignition harness for suspected leakage?
A high amperage dc ammeter. A high tension lead tester. A high voltage dc voltmeter.
After making a welded repair to a pressurized type turbine engine oil tank, the tank should be pressure checked to:
not less than 5 PSI plus the average operating pressure of the tank. 5 PSI. not less than 5 PSI plus the maximum operating pressure of the tank.
The floating control thermostat, used on some reciprocating engine installations, helps regulate oil temperature by:
controlling oil flow through the oil cooler. controlling air flow through the oil cooler. recirculating hot oil back through the sump.
What is a basic advantage of using ac for electrical power for a large aircraft?
AC systems operate at lower voltage than DC systems and therefore use less current and can use smaller and lighter weight wiring. AC systems operate at higher voltage than DC systems and therefore use more current and can use smaller and lighter weight wiring. AC systems operate at higher voltage than DC systems and therefore use less current and can use smaller and lighter weight wiring.
For what primary purpose is a turbine engine fuel control unit trimmed?
To obtain maximum thrust output when desired. To properly position the power levers. To adjust the idle RPM.
When the centrifugal force acting on the propeller governor flyweights overcomes the tension on the speeder spring, a propeller is in what speed condition?
Underspeed. Overspeed. On speed.
Which of the following are distinct circuits of a high tension magneto?
1. Magnetic.
2. Primary.
3. E gap.
4. P lead.
5. Secondary.
2, 4, 5. 1, 2, 5. 1, 3, 4.
As a general rule, the mixture setting on a reciprocating engine operating at or near takeoff power that provides the best cooling is:
LEAN. FULL RICH. FULL LEAN.
Why is high nickel chromium steel used in many exhaust systems?
Corrosion resistance and low expansion coefficient. High heat conductivity and flexibility. Corrosion resistance and high heat conductivity.
What is the position of the cowl flaps during engine starting and warmup operations under normal conditions?
Open for starting, closed for warmup. Full open at all times. Full closed at all times.
How many secondary coils are required in a low tension ignition system on an 18 cylinder engine?
36. 18. 9.
A hissing sound from the exhaust stacks when the propeller is being pulled through manually indicates:
exhaust valve blow by. a cracked exhaust stack. worn piston rings.
Specific gravity is a comparison of the weight of a substance to the weight of an equal volume of:
oil at a specific temperature. mercury at a specific temperature. distilled water at a specific temperature.
An aircraft reciprocating engine using hydraulic valve lifters is observed to have no clearance in its valve-operating mechanism after the minimum inlet oil and cylinder head temperatures for takeoff have been reached. When can this condition be expected?
When the lifters become deflated. During normal operation. As a result of carbon and sludge becoming trapped in the lifter and restricting its motion.
Which of the following may be used to accomplish internal inspection of an assembled turbine engine?
1. Infrared photography.
2. Ultrasound.
3. A borescope.
4. Fluorescent penetrant and ultraviolet light.
3. 1, 3. 1, 2, 3.
The procedure for removing the accumulation of dirt deposits on compressor blades is called:
the purging process. the soak method. field cleaning.
What basic meter is used to indicate cylinder head temperature in most aircraft?
Thermocouple type meter. Galvanometer. Electrodynamometer.
By use of a differential pressure compression tester, it is determined that the No. 3 cylinder of a nine cylinder radial engine will not hold pressure after the crankshaft has been rotated 260° from top dead center compression stroke No. 1 cylinder. How can this indication usually be interpreted?
A normal indication. Exhaust valve blow by. A damaged exhaust valve or insufficient exhaust valve clearance.
During idle mixture adjustments, which of the following is normally observed to determine when the correct mixture has been achieved?
Fuel flowmeter. Changes in RPM or manifold pressure. Changes in fuel/air pressure ratio.
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