What controls the constant speed range of a constant speed propeller?
Angle of climb and descent with accompanying changes in airspeed. Engine RPM. The mechanical limits in the propeller pitch range.
If staggered ignition timing is used, the:
spark will be automatically advanced as engine speed increases. spark plug nearest the exhaust valve will fire first. spark plug nearest the intake valve will fire first.
What is the relationship between the pressure existing within the throat of a venturi and the velocity of the air passing through the venturi?
The pressure is inversely proportional to the velocity. The pressure is directly proportional to the velocity. There is no direct relationship between the pressure and the velocity.
Which of the following causes a single diaphragm accelerator pump to discharge fuel?
An increase in manifold pressure that occurs when the throttle valve is opened. A decrease in manifold pressure that occurs when the throttle valve is opened. An increase in venturi suction when the throttle valve is open.
In a low tension ignition system, each spark plug requires an individual:
secondary coil. breaker assembly. capacitor.
When a magneto is disassembled, keepers are usually placed across the poles of the rotating magnet to reduce the loss of magnetism. These keepers are usually made of:
cobalt steel. soft iron. chrome magnet steel.
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:
disconnected from the power supply circuit. 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. 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.
The aerodynamic force acting on a rotating propeller blade operating at a normal pitch angle tends to:
bend the blades rearward in the line of flight. increase the pitch angle. reduce the pitch angle.
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.
Excessive valve clearances will cause the duration of valve opening to:
increase for both intake and exhaust valves. decrease for both intake and exhaust valves. decrease for intake valves and increase for exhaust valves.
Air turbine starters are generally designed so that reduction gear distress or damage may be detected by:
characteristic sounds from the starter assembly during engine start. inspection of a magnetic chip detector. breakage of a shear section on the starter drive shaft.
Why are fixed orifice nozzles used in the lubrication system of gas turbine engines?
To keep back pressure on the oil pump, thus preventing an air lock. To protect the oil seals by preventing excessive pressure from entering the bearing cavities. To provide a relatively constant oil flow to the main bearings at all engine speeds.
Turbine nozzle diaphragms located on the upstream side of each turbine wheel, are used in the gas turbine engine to:
decrease the velocity of the heated gases flowing past this point. increase the velocity of the heated gases flowing past this point. direct the flow of gases parallel to the vertical line of the turbine blades.
The valve clearance of an engine using hydraulic lifters, when the lifters are completely flat, or empty, should not exceed:
a specified amount below zero. a specified amount above zero. 0.00 inch.
Where is the highest gas pressure in a turbojet engine?
At the outlet of the tailpipe section. At the entrance of the turbine section. In the entrance of the burner section.
What is the purpose of the safety circlet installed on some valve stems?
To prevent valves from falling into the combustion chamber. To hold the valve guide in position. To hold the valve spring retaining washer in position.
The low pitch stop on a constant speed propeller is usually set so that:
the engine will turn at its rated takeoff RPM at sea level when the throttle is opened to allowable takeoff manifold pressure. maximum allowable engine RPM cannot be exceeded with any combination of manifold pressure, altitude, or forward speed. the limiting engine manifold pressure cannot be exceeded with any combination of throttle opening, altitude, or forward speed.
Which of the following will decrease volumetric efficiency in a reciprocating engine?
1. Full throttle operation.
2. Low cylinder head temperatures.
3. Improper valve timing.
4. Sharp bends in the induction system.
5. High carburetor air temperatures.
2, 4, and 5. 3, 4, and 5. 1, 2, 3, and 4.
Removal of propeller blade tips within Type Certificate Data Sheet limits when correcting a defect is:
a major repair. permitted under the privileges and limitations of a powerplant rating. a major alteration.
The spark is produced in a magneto ignition system when the breaker points are:
fully open. beginning to open. fully closed.
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.
Which of the following is NOT an input parameter for a turbine engine fuel control unit?
Ambient humidity. Compressor inlet pressure. Compressor inlet temperature.
The propeller blade angle is defined as the acute angle between the airfoil section chord line (at the blade reference station) and which of the following?
The relative wind. The axis of blade rotation during pitch change. The plane of rotation.
Why is a constant speed counterweight propeller normally placed in full HIGH PITCH position before the engine is stopped?
To prevent hydraulic lock of the piston when the oil cools. To prevent exposure and corrosion of the pitch changing mechanism. To prevent overheating of the engine during the next start.
Magneto breaker point opening relative to the position of the rotating magnet and distributor rotor (internal timing) can be set most accurately:
during assembly of the magneto before installation on the engine. by setting the points roughly at the required clearance before installing the magneto and then making the fine breaker point adjustment after installation to compensate for wear in the magneto drive train. during the magneto to engine timing operation.
An engine becomes overheated due to excessive taxiing or improper ground runup. Prior to shutdown, operation must continue until cylinders have cooled, by running engine at:
idle RPM. low RPM with oil dilution system activated. high RPM with mixture control in rich position.
Select the statement which is correct relating to a fuel level check of a float type carburetor.
Use 5 pounds fuel pressure for the test if the carburetor is to be used in a gravity fuel feed system. Block off the main and idle jets to prevent a continuous flow of fuel through the jets. Do not measure the level at the edge of the float chamber.
If the exhaust valve of a four stroke cycle engine is closed and the intake valve is just closed, the piston is on the:
intake stroke. power stroke. compression stroke.
How are the rotor windings of an aircraft alternator usually excited?
By a variable direct current. By a constant ac voltage. By a constant ac voltage from the battery.
The basic oil pressure relief valve setting for a newly overhauled engine is made:
in the overhaul shop. when the oil is at a higher than normal temperature to assure high oil pressure at normal oil temperature. within the first 30 seconds of engine operation.
The purpose of a sonic venturi on a turbocharged engine is to:
increase the velocity of the fuel/air charge. increase the amount of air that can flow from the turbocharger into the cabin for pressurization. limit the amount of air that can flow from the turbocharger into the cabin for pressurization.
What is the purpose of a safety gap in some magnetos?
To ground the magneto when the ignition switch is off. To prevent flashover in the distributor. To discharge the secondary coil's voltage if an open occurs in the secondary circuit.
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?
Alternate air door stuck open. Carburetor icing. One or more fuel nozzles are clogged.
Compared to reciprocating engine oils, the types of oils used in turbine engines:
are required to carry and disperse a higher level of combustion by-products. may permit a somewhat higher level of carbon formation in the engine. have less tendency to produce lacquer or coke.
What is indicated when the front cone bottoms while installing a propeller?
Blade angles are incorrect. Propeller dome combination is incorrect. Rear cone should be moved forward.
Removal of propeller blade tips within Type Certificate Data Sheet limits when correcting a defect is:
a major repair. permitted under the privileges and limitations of a powerplant rating. a major alteration.
If it is found that a shielded ignition system does not adequately reduce ignition noise, it may be necessary to install: bonding wires from the shielding to ground. a filter between the magneto and magneto switch. a second layer of shielding.
Under which of the following conditions is the oil cooler flow control valve open on a reciprocating engine?
When the temperature of the oil returning from the engine is too low. When the scavenger pump output volume exceeds the engine pump input volume. When the temperature of the oil returning from the engine is too high.
What is the purpose of a slip joint in an exhaust collector ring?
It permits the collector ring to be installed in one piece. It aids in alignment and absorbs expansion. It reduces vibration and increases cooling.
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.
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