Font size
WorksheetsEngine Mechanics Quiz
Total questions: 122
Worksheet time: 61hrs 0mins
Which stroke piston going down?
Exhaust stroke
Intake stroke
Compression stroke
Power
What connect piston and crankshaft ?
Cylinder sleeve
Connecting rod
Crank pin
Piston ring
Which is not valve head configuration
J-head
T-head
I-head
L-head
During which stroke of a four -stroke engine is the exhaust valve open?
Intake
Exhaust
Compression
Power
During which stroke of a four -stroke engine is both valve closed and piston move from TDC to BDC?
Intake
Exhaust
Power
Compression
During which stroke of a four -stroke engine is both valve closed and piston move from BDC to TDC?
Power
Intake
Compression
Exhaust
What is the correct Firing order of 4 cylinder inline
4-3-2-1
1-2-4-3
2-1-3-4
3-2-1-4
What is the correct Firing order of 6 cylinder inline
2-1-3-4-6-5
1-5-3-6-2-4
3-2-1-4-5-6
4-3-2-1-5-6
What is the correct Firing order of 4 cylinder opposed engine
1-3-2-4
4-2-3-1
2-1-3-4
4-3-2-1
What is the correct Firing order of Textron -Lycoming 6 cylinder opposed engine
2-1-3-4-6-5
1-4-5-2-3-6
3-2-1-4-5-6
4-3-2-1-5-6
What is the correct Firing order of Continental motors 6 cylinder opposed engine
3-2-1-4-5-6
1-6-3-2-5-4
2-1-3-4-6-5
4-3-2-1-5-6
What is the correct Firing order of 9 cylinder single row radial engine
2-1-3-4-6-5-8-7-9
3-2-1-4-5-6-7-8-9
1-3-5-7-9-2-4-6-8
4-3-2-1-5-6-7-9-8
What is the purpose of a Test Club Propeller (TCP) in engine testing?
To provide load and cooling airflow during engine test runs
To reduce engine friction during idling
To measure fuel pressure entering the carburetor
For actual flight to increase aircraft lift
Who defined “Horsepower” and established the standard of 1 hp = 550 ft.lb/sec?
Albert Einstein
Isaac Newton
James Watt
Nikola Tesla
What is Indicated Horsepower (IHP)?
The horsepower lost to auxiliary devices such as fuel and oil pumps
The horsepower measured directly at the crankshaft
The horsepower calculated from the indicated mean effective pressure in the cylinder, without reference to friction losses
The actual power delivered to the propeller after friction losses
What is Brake Horsepower (bhp)?
The power required to start the engine
The theoretical power of an engine without considering friction losses
The power lost in overcoming mechanical friction inside the engine
The actual horsepower delivered to the propeller for useful work after subtracting friction losses
The ignition system has 4 main parts. Which one is not included?
The ignition harness
The distributor
The spark plug
The detonator
What are the advantages of the Rich Mixture?
More power loss
Better fuel cooling action
Safeguard against engine damage
A and C are correct
What is the primary function of the connecting rod in a piston engine?
To reduce friction between crankshaft and bearings
To open and close the intake valves
To carry the forces from the piston to the crankshaft
To act as the combustion chamber
Which of the following statements about the crankshaft in piston engines is correct?
The crankshaft supports the piston directly without the connecting rod.
The crankshaft converts reciprocating motion of the piston into rotary motion to drive the propeller.
The crankshaft only rotates the camshaft and does not transmit piston forces.
The crankshaft is only used in radial engines and not in in -line or opposed engines.
Why is the cylinder head of an air -cooled piston engine usually made of alum inium alloy?
To provide maximum strength
To withstand high combustion pressure
To conduct heat efficiently and reduce weight
To ease the assembly with the cylinder barrel
How are the cylinders of a single -row radial engine numbered?
Starting at the bottom right, clockwise
Starting at the bottom left, counter -clockwise
Starting at the top, counter -clockwise
Starting at the top, clockwise
Why do valve need two helical coil spring to operate?
To damp out all the spring surge vibration during engine operation
To reduce the possibility of fa ilure by breakage from heat and metal fatique
Two better than one
Both A and B are correct
What is the advantages of sleeve valve?
Unlimited speed operation
Low carbon built -up
It have high volumetric efficiency
Low oil consumption
What is the angle of exhaust valve seat and face?
60° or 90°
30° or 45°
45° or 60°
45° or 90°
What is the angle of exhaust valve seat and face?
60° or 90°
30° or 45°
45° or 60°
45° or 90°
Why valve that have liquid sodium in the stem should not be cut open?
It may contaminate other component
It could cause an explosion
The part may be loose in the engine
It shouldn't be cut open
Which of this poppet valve types are wrong?
Philip type
Tulip type
Semi-tulip type
Mushroom type
What cause valve sticking?
Dirty oil
Built-up carbon dioxide
Clean air filter
Low cylinder temperature
Nitriding of a cylinder barrel typically hardens the surface to a depth of about:
0.200 inch
0.002 inch
0.020 inch
2.000 inch
Where is a double throw crankshaft arrangement typically found?
In a two -row radial engine, one throw for each row of cylinders
In an i n-line six -cylinder engine
In a single -cylinder in -line engine
In a single row radial engine
What is th e main purpose of a dynamic damper fitted to a crankshaft?
To provide additional lubrication to journals
To attach the prop eller to the crankshaft
To absorb and balance out vibration forces from power impulses
To increase the crankshaft’s overall strength
Which method is used to reduce vibration in single -throw crankshafts for radial engines?
Using counterweights or dynamic balancing
Using hollow crank pins
Increasing the thickness of the journals
Adding lubricating grooves
What is the main function of crankshaft journa ls?
To attach connecting rods to the crankshaft
To balance vibrations during rotation
To reduce engine noise during operation
To support the crankshaft within the main bearings
What is the purpose of carburetor ?
Meter into this air the correct amount of atomised liquid gasoline.
Maintain a constant proportion of fuel and air.
Measure the amount of air entering the engine.
All above
Which is not a flow of air through a venturi ?
Side draft
Diagonal draft
Down draft
Up draft
What is the chief disadvantage of the float -type carburetor?
Incomplete vaporisation due to low fuel pressure
Its icing tendency
Difficulty in use with supercharged systems
Its response to abrupt manoeuvres
Why is a separate idling system necessary in a carburetor?
Because the main discharge nozzle cannot supply fuel when the throttle is closed
Because the float chamber is empty at low RPM
Because the Venturi does not create any airflow at idle
Because the throttle valve cannot control airflow at idle
What is the primary reason engine power decreases when carburetor heat is applied?
The fuel -to-air ratio automatically corrects itself, reducing efficiency
Warm air has lower density, re ducing the mass of air available for combustion
The carburetor flap partially closes, restricting airflow
The exhaust manifold absorbs some of the combustion gases
How is the air metering force created in the throttle body?
By the pressure differentia l between chamber A and chamber B
By the action of the throttle stop
By the flow of unmetered fuel through the regulator
By the movement of the idle valve
What is the function of Chamber C in the regulator?
Contains unmetered fuel pressure
Contains metered fuel pressure
Holds impact air pressure
Holds pump delivery pressure
At idle , how does the flow divider distribute fuel?
The valve opens slightly, exposing the V -slot for equal distribution
Fuel pressure is negligible, so no fuel reaches the nozzles
The fl ow divider bypasses fuel directly to the fuel pump
The valve is fully open, allowing unrestricted flow
What is the purpose of the enrichment jet installed in parallel with the main metering jet?
To balance fuel flow among cylinders
To increase fuel/air mixture strength for engine cooling at high power
To reduce fuel consumption
To improve idle smoothness
What is one of the unique features of the fuel injector pump assembly?
It bypasses fuel directly to the cylinders at idle
It removes vapours from fuel and vents them back to the fuel tank
It eliminates the need for a fuel control unit
It prevents air metering force from fluctuating
What is the main advantage of the extremely high p ressure in a common -rail system?
It assures better vaporisation and cleaner combustion
It reduces the need for a fuel pump
It eliminates the need for FADEC
It allows the engine to run without injectors
What does FADEC stand for?
Full Automatic Dual Engine Controller.
Full Authority Digital Electronic control.
Finalized Analog Engine Control.
Fundamental Authority Digital Electronic Computer.
What to do if both sensors malfunction in dually redundant?
Is switch to using a sensor from a non -redundant system.
Use power source.
All of above.
Use synthetic software default values.
What does the FADEC control?
Fuel supply only
Ignition only
Both fuel mixture and ignition
Cockpit electrical systems
What is the difference between an EEC and FADEC?
EEC allows manual override, but FADEC does not
EEC has no backup capability
Neither allows manual override
FADEC allows manual override, but EEC does not
Which of the following is listed as an advantage of FADEC?
Increases engine weight
Requires constant pilot mixture adjustment
Provides better fuel efficiency
Operates without any electrical power
If the aircraft’s primary electrical system fails, how long can the FADEC battery supply the EEC?
Only when alternator is running
Until fuel runs out
It cannot operate at all
Approximately 2 hours
Which type of magneto is the most widely used today?
Stationary magnet type
Rotating magnet type
Rotating armature type
Dual-magnet type
What happens when the ignition switch is set to the “BOTH” position?
Both magnetos supply current, and both spark plugs fire in each cylinder.
Both magnetos supply current, but only one spark plug fires in each cylinder.
Only one magneto supplies current, and only one spark plug fires in each cylinder.
The ignition system is completely off, and no spark plugs fire.
What do dry, fluffy black deposits on a spark plug usually indicate?
Proper spark plug heat range
Correct fuel/air mixture at cruise power
Carbon fouling caused by a rich fuel/air mixture
Normal combustion deposits
What material is used for the armature core in the high -tension booster coil?
Soft iron
Aluminum
Copper
Stainless steel
Where does the low -tension booster coil get its current from?
Aircraft system
Battery charger
Magneto only
Spark plug
When the pilot operated mag switch is off the primary circuit is.
Full
Ground
Opened
Closed
What is function of capacitor in low tension circuit
All above
Stop voltage
Slow down current
Aids the rapid collapse of the primary’s circuit field
What are 2 types of magneto rotating components
Rotating magneto, Rotating armature
None above
Rotating armature, Rotating magnet
Rotating Field , Rotating magneto
What is the relationship of speed of the distributors and crankshaft speed in the reciprocating engine
The distributor turns at one and one fourth of crankshaft speed
The distributor turns at one half of crankshaft speed
The distributor turns at one fourth of crankshaft speed
The crankshaft turns two times of distributor
When ground checking is being performed the engine’s rpm is
Slightly increase
Not change
Slightly drop
Same
Why is an automatic timing adjuster used in an engine ignition system?
To prevent spring and cam wear in the ignition system.
To adjust ignition timing according to engine speed using centrifugal force.
To automatically maintain the correct air -fuel ratio.
To keep the manifold pressure constant during high -power operation.
What is the primary function of an air filter installed in an induction system?
Cools the air to increase air density.
Increases the pressure of air entering the engine.
Prevents ice buildup in the air ducts.
Filters out dust and dirt before entering the system.
Which one is advantage of the NACA intake?
It is mounted off the fuselage to reduce the boundary layer.
It directly increases air pressure into the engine.
It is used only in high -speed aircraft.
It is flush with the aircraft's surface to reduce drag.
Why is an induction leak a serious problem in an engine's induction manifold?
It alters the fuel/air mix ture and affects CHT temperature.
It causes the fuel system to deliver less fuel than required.
It disrupts oil sump lubrication.
It increases system pressure, causing detonation.
What was the main benefit of the NACA cowling ?
It completely eliminated the need for cowl flaps.
It reduced aerodynamic drag while also improving engine cooling.
What was the main benefit of the NACA cowling ?
It completely eliminated the need for cowl flaps.
It reduced aerodynamic drag while also improving engine cooling.
It allowed radial engines to operate without airflow from the propeller.
It increased backpressure to improve exhaust performance.
What is one main advantage of superchargers compared to turbochargers?
They are lighter and cheaper to install than turbos.
They are more fuel -efficient than turbos.
They use waste air from exhaust gases.
They run at cooler temperatures and have no lag.
Why can a significant rise in air temperature be harmful in a supercharged engine?
It prevents fuel from atomizing properly, causing incomplete vaporization
It decreases air density and increases the chan ce of detonation.
It cools the air, reducing combustion efficiency.
It increases air density, making the mixture too rich.
It consists of a driven inner member with several wedgeshaped fingers extending from it.
Hydraulic torque converter
The centrifugal friction clutch
Variable datum control
Spring drive
Why do turbocharging engines often have intercoolers?
To improve lubrication of the turbocharger bearings.
To increase the density of the compressed air.
To reduce friction in the intake system.
To reduce the velocity of the exhaust gases pas sing through the turbine.
What is the most important property of lubricating oil in a reciprocating engine?
Its viscosity
Its smell
Its weight
Its color
What is the primary function of ashless dispersant additives in lubricating oils?
To dissolve and keep harmful metallic ash particles in suspension.
To make the oil more effective in extreme pressure conditions.
To prevent the oil from freezing at low temperatures.
To increase the oil's viscosity.
What is the property of a high -viscosity lubricating oil?
Flows very easily like water
Has no effect on lubrication
Difficult to pour and runs slowly
Becomes thinner at cold temperatures
What is the recommended oil for most aero diesel engines?
10W-40 multigrade synthetic oil
Automotive gasoline engine oil
SAE 30 single -grade oil
Avgas mixed oil
What is the color of Avgas 100LL (Low Lead)?
Red
Green
Purple
Blue
What is the main risk of using Mogas with bio -alcohol?
Reduces exhaust gas temperature
Increases engine power
Improves lubrication
Freezes water and causes corrosion
The purpose of lubicating oil in piston engine is
Reduce friction
Cleanliness
Provide cooling
All of above
What supply oil under pressure to engine?
Oil pump
None of above
Oil cooler
Oil filter
What are the two types of oil filters used in aircraft engines, and what materials are they made from?
Fine filter – made of wire mesh element Coarse filter – made of paper element
Both fine and coarse filters are made of the same material, stainless steel alloy
Fine filter – made of cotton gauze Coarse filter – made of foam element
Fine filter – made of paper element Coarse filter – made of wire mesh element
What is the function of the pressure relief valve in the lubrication system?
To filter out contaminants from the oil
To increase oil consumption during cruise
To maintain oil pressure within specified limits
To reduce oil temperature at high altitude
Which factor does NOT affect how much oil an aircraft engine uses?
The type o f oil used
Number of cylinders
Engine paint color
Operating temperature of the engine
What materials are oil filter elements usually made of?
Porous paper or wire gauze
Cotton fabric
Stainless steel only
Titanium mesh
Which one is the primary instrument
Engine speed revs per minute
Exhaust gas temperature
Oil filler cap temperature
Cylinder head temperature
Which Hobb meter method is used for commercial operators
When the magnetos are turned off
When the electric system is on
When oil pressure is running
Sensing vane under a wing or pressure switch attaches at landing gear
Which t ype of drive coupling use with tachometer generator
Chain, Pulley, Belt
Magnetic clutch with spring tension
Flexible, Splined, Two -pin
Rigid, Splined, Gear
Which method uses a bulb with volatile liquid and a Bourdon tube to measure temperature?
Gas expansion
Bimetallic strip
Thermocouple junction method
Non-electrical temperature measurement
In a DC ratiometer temperature -sensing system, what happens if the sensor circuit is open?
The instrument goes to a minimum
The readout is unaffected by supply voltage
The instrument goes to full -scale deflection
The needle fluctuates randomly without settling
Why is carburettor heat applied during engine operation?
To reduce back pressure in the exhaust system
To prevent or remove ice formation in the carburettor
To enrich the mixture for more power
To cool the intake air for better combustion
What does the abbreviation CHT stand for?
Cylinder Head Temperature
Cabin Humidity Test
Cooling Heat Transfer
Compressor High Thrust
What principle does the thermocouple connected to the indicator use?
Optical reflection
Resistance change
Electromotive force (EMF) from heat difference
Magnetic induction
What is the minimum allowable fuel pressure during flight?
3 psi
5 psi
10 psi
1 psi
What do absolute pressure instruments measure?
Dynamic pressure only
Pressure from zero or vacuum reference
Pressure relative to atmospheric pressure
Difference between two pressures
What is the formula for calculating fuel used?
Fuel flow × time = fuel used
Fuel density × RPM = fuel used
Fuel flow × distance = fuel used
Fuel pressure ÷ time = fuel used
What is the principle of an ultrasonic fuel flow sensor?
Electromagnetic induction
Optical beam interruption
Pulse of ultrasound measuring time difference
Resistance change due to temperature
When the aircraft is airborne, what additional stress acts on the engine mount?
Torsional stress
Fuel flow pressure
Exhaust pressure
Cowling aerodynamic force
What happens to a rod under tension loads?
It expands in diameter
It loses elasticity
It tends to increase a bend
It tends to decrease a bend
Ball-bearing control cables are a type of:
Teleflex rod
Push-pull cable
Electrical conductor
Hydraulic line
Before lifting the engine from the mount, what must be done for safety?
Check that the sling is in good condition and can support the weight.
Always remove the governor.
Use manual power to lift the engine instead of a hoist.
Let the fuel run out.
What is the primary function of carburetor heat control?
Increases air pressure into the carburetor.
Reduces vibrations caused by the propeller.
Vaporizes fuel more quickly in the fuel tank.
Uses heat from the exhaust system to prevent icing of the manifold
When is the Magneto Check performed during ground run?
After engine shutdown
At idle only
During run-up
Before engine start
What is true about Piston repairs?
Piston can reduced below the specific minimum.
Remove more than on the piston skirt.
Not required as often as cylinder repairs most of the wear is between the piston ring and cylinder
Piston weight cannot be decreased easily.
What is a component that commonly causes engine failure?
Cam shaft
Fuel injector nozzle
Bearing, connecting rod
Crank case
What is the benefit of low power cruise?
Extended ranges
Increased engine wear
Good for climb and take off
Low speed
What to avoid during engine shutdown?
Over speed
Fuel starvation
Over boost
Thermal shock
The purpose of refacing valve seat?
Improve oil circulation
Faster ignition
Tight and proper seal
Reduce fuel consumption
How often to do valve reconditioning?
Every overhaul
Every 500 flight hours
Every 3 years
Every 2 years
When to do a propeller check during ground run-up?
Only after engine shutdown
During
Before, after
Before, after, and during
What causes backfiring?
Insufficient ignition timing
Properly adjusted fuel mixture.
Fuel burns too slowly
More fuel than required that explodes in the intake manifold
What causes after firing?
Too rich mixture
Incorrect valve timing
Too lean mixture
Fast burning fuel
What is the normal procedure for engine preservation?
Drain regular lubricant and fill with corrosion preventive oil before preservation
Regularly move propeller and crankshaft
Store engine without any special treatment
Engine is robust, preservation is not necessary
When preserving an aircraft engine for more than four weeks but less than one year, which of the following is NOT a correct procedure?
Leave all engine openings (exhaust, intake, vent) uncovered to allow ventilation
Drain the fuel from tanks, lines, and carburetor float chambers
Inject about 6 cm³ of preservative oil into each cylinder through the spark plug holes
Spray external steel parts with engine oil to protect against corrosion
In a helicopter, the engine must be connected to the powertrain through which device so that the engine can operate independently of the rotor?
Governor
Carburetor heat control
Pilot- operated clutch
twist - grip throttle
The two double-lobed impellers rotate in opposite directions and increase the flow of air into the cylinder
The centrifugal supercharger
The Roots supercharger
The vane supercharger
The axial flow supercharger
Why does a supercharged engine require significant engine power to operate, and why is it still considered effective?
Because it consumes extra fuel but provides no increase in power.
Because although it uses engine power, the increase in air and fuel leads to higher overall power output.
Because it reduces manifold pressure, resulting in lower efficiency
Because it operates only at high altitudes where turbos are ineffective.
Why does the exhaust system of an piston engine using a heater muff arrangement require special inspection?
To prevent excessive expansion and rupture of the exhaust pipe.
To prevent excessive heat buildup in the exhaust pipe.
To prevent carbon monoxide leakage into the cockpit.
To ensure even circulation of hot air.
In a liquid-cooled engine, which component controls the flow of coolant through the radiator in order to maintain the minimum coolant temperature while the engine is running?
Water pump
Header tank
Radiator shutters
Thermostat
Which of the following actions is NOT recommended during spark plug installation according to the document?
Apply anti-seize compound (e.g., graphite grease) lightly to body threads, avoiding electrodes and washer face.
Use an open-ended spanner for plug fitting to prevent cracking of the insulator.
Ensure the correct type and serviceable sealing washer is fitted before installation.
Confirm that the cylinder head thread is clean before fitting the spark plug
Which of the following statements best explains why evaporation ice is considered the most serious form of carburetor icing?
Because it forms only at freezing point and can block the intake lip quickly
Because it can form at relatively warm temperatures due to combined Venturi and vaporisation cooling effects
Because it only affects turbocharged engines and cannot be removed by carburetor heat
Because it is limited to conditions of snow, sleet, or sub-zero clouds and rarely occurs otherwise
In modern aircraft engines, the threaded-joint method is used to join the cylinder barrel to the cylinder head. Which statement best explains why this method is effective?
It requires no heating or cooling during installation.
It allows for frequent disassembly without thread damage.
The interference fit prevents loosening under high temperature operation
It provides weaker sealing but easier maintenance.
Which of the following is NOT one of the four principal requirements for an aircraft piston cylinder assembly?
Lightweight construction to reduce engine mass
Ability to withstand internal pressure and high temperature
Complex manufacturing process for higher precision
Good heat-conducting properties for efficient cooling
In a standard in-line engine, the number of cylinders is generally limited to how many, to ensure effective cooling?
4
6
8
12