A&P Powerplant Oral Exam Prep
Test Bank | Aviation Mechanic
Questions and Answers (2026)
‣ What is the running valve clearance on engines equipped with
hydraulic valve lifters -✓✓Zero
‣ When troubleshooting a running engine malfunction, what does a cold
cylinder indicate? -✓✓Lack of combustion in that cylinder.
‣ What factors about the condition of an engine can be learned by
studying the results of a compression test? -✓✓The results of a
compression test determine if the valves, piston rings, and pistons are
adequately sealing.
‣ What should be done to repair a loose stud in an engine crankcase? -
✓✓Remove the loose stud, and inspect the hole for size and the
condition of the threads. It may be necessary to use a suitable oversize
stud.
‣ How is a cylinder barrel inspected for out of roundness? -✓✓A dial
indicator can be used to measure at the top of the cylinder and also at the
skirt. Two readings should be taken, 90 degrees to each other.
,‣ What type of connecting rods are commonly found in redial engines? -
✓✓Master and articulated rod assemblies.
‣ What are the different types of piston rings? -✓✓Compression, oil
control, and oil scraper.
‣ What is the purpose of oil control rings? -✓✓Oil control rings regulate
the thickness of the oil film on the cylinder wall.
‣ What types of bearings are in general use in reciprocating engines? -
✓✓Plain, ball, and roller.
‣ Where are cracks most likely to be found in a piston? -✓✓Highly
stressed areas; the base of the pin bosses, inside at the junction of the
head and walls, and the ring lands.
‣ How are piston ring gaps installed relative to each other on a piston,
and why? -✓✓Compression ring gaps should be installed in staggered
positions around the piston in order to prevent excessive blow-by.
‣ What is the purpose of valve overlap? -✓✓It permits better volumetric
efficiency and lowers the cylinder operating temperature.
‣ What is the purpose of crankshaft dynamic dampers? -✓✓To reduce
engine vibration.
,‣ What is meant when it is said that an engine part is within "serviceable
limits"? -✓✓A part that is within "serviceable limits" will not likely
wear to the point of causing engine failure within the next time between
overhaul interval.
‣ Name at least one part of an inspection that should be made after a
propeller strike. -✓✓1. Inspect the engine mounts, crankcase, and nose
section for damage.
2. Inspect the oil and oil screens/filters for metal particles.
3. Inspect the propeller drive shaft or crankshaft for misalignment.
‣ What are some precautions to be observed when preparing an aircraft
for engine removal? -✓✓Disconnect the battery, chock the wheels,
install a tail stand, and turn off the fuel valves.
‣ What is an indication that a primer is leaking or is open during engine
operation? -✓✓The engine will not idle properly.
‣ What may be the result of incorrect installation of piston rings? -
✓✓Excessive oil consumption.
‣ What are some indications of induction system leakage? -✓✓Low
power and uneven running.
, ‣ When an engine is rebuilt by the manufacturer, how is its operating
history affected? -✓✓A rebuilt engine is considered to have no previous
operating history and can therefore be issued a zero-time record.
‣ What is used in an aircraft engine to help prevent valve surge or float
from occurring? -✓✓Two or more springs on each valve.
‣ What are the major components of a typical gas turbine engine? -
✓✓An air inlet, compressor section, combustion section, turbine section,
exhaust section, and accessory section.
‣ What determines the amount of air passing through a turbine engine? -
✓✓Compressor speed, forward speed of the aircraft, and air density.
‣ What are the two principle types of compressors currently used in
turbine engines? -✓✓Centrifugal and axial flow.
‣ How are turbine engine rotor blades attached to rotor disks? -✓✓1.
Bulb-type root
2. Fir tree-type root
3. Dovetail-type root
‣ Name at least three types of combustion chamber systems. -✓✓1. Can
2. Annular
3. Can-annular
Test Bank | Aviation Mechanic
Questions and Answers (2026)
‣ What is the running valve clearance on engines equipped with
hydraulic valve lifters -✓✓Zero
‣ When troubleshooting a running engine malfunction, what does a cold
cylinder indicate? -✓✓Lack of combustion in that cylinder.
‣ What factors about the condition of an engine can be learned by
studying the results of a compression test? -✓✓The results of a
compression test determine if the valves, piston rings, and pistons are
adequately sealing.
‣ What should be done to repair a loose stud in an engine crankcase? -
✓✓Remove the loose stud, and inspect the hole for size and the
condition of the threads. It may be necessary to use a suitable oversize
stud.
‣ How is a cylinder barrel inspected for out of roundness? -✓✓A dial
indicator can be used to measure at the top of the cylinder and also at the
skirt. Two readings should be taken, 90 degrees to each other.
,‣ What type of connecting rods are commonly found in redial engines? -
✓✓Master and articulated rod assemblies.
‣ What are the different types of piston rings? -✓✓Compression, oil
control, and oil scraper.
‣ What is the purpose of oil control rings? -✓✓Oil control rings regulate
the thickness of the oil film on the cylinder wall.
‣ What types of bearings are in general use in reciprocating engines? -
✓✓Plain, ball, and roller.
‣ Where are cracks most likely to be found in a piston? -✓✓Highly
stressed areas; the base of the pin bosses, inside at the junction of the
head and walls, and the ring lands.
‣ How are piston ring gaps installed relative to each other on a piston,
and why? -✓✓Compression ring gaps should be installed in staggered
positions around the piston in order to prevent excessive blow-by.
‣ What is the purpose of valve overlap? -✓✓It permits better volumetric
efficiency and lowers the cylinder operating temperature.
‣ What is the purpose of crankshaft dynamic dampers? -✓✓To reduce
engine vibration.
,‣ What is meant when it is said that an engine part is within "serviceable
limits"? -✓✓A part that is within "serviceable limits" will not likely
wear to the point of causing engine failure within the next time between
overhaul interval.
‣ Name at least one part of an inspection that should be made after a
propeller strike. -✓✓1. Inspect the engine mounts, crankcase, and nose
section for damage.
2. Inspect the oil and oil screens/filters for metal particles.
3. Inspect the propeller drive shaft or crankshaft for misalignment.
‣ What are some precautions to be observed when preparing an aircraft
for engine removal? -✓✓Disconnect the battery, chock the wheels,
install a tail stand, and turn off the fuel valves.
‣ What is an indication that a primer is leaking or is open during engine
operation? -✓✓The engine will not idle properly.
‣ What may be the result of incorrect installation of piston rings? -
✓✓Excessive oil consumption.
‣ What are some indications of induction system leakage? -✓✓Low
power and uneven running.
, ‣ When an engine is rebuilt by the manufacturer, how is its operating
history affected? -✓✓A rebuilt engine is considered to have no previous
operating history and can therefore be issued a zero-time record.
‣ What is used in an aircraft engine to help prevent valve surge or float
from occurring? -✓✓Two or more springs on each valve.
‣ What are the major components of a typical gas turbine engine? -
✓✓An air inlet, compressor section, combustion section, turbine section,
exhaust section, and accessory section.
‣ What determines the amount of air passing through a turbine engine? -
✓✓Compressor speed, forward speed of the aircraft, and air density.
‣ What are the two principle types of compressors currently used in
turbine engines? -✓✓Centrifugal and axial flow.
‣ How are turbine engine rotor blades attached to rotor disks? -✓✓1.
Bulb-type root
2. Fir tree-type root
3. Dovetail-type root
‣ Name at least three types of combustion chamber systems. -✓✓1. Can
2. Annular
3. Can-annular
