A&P - Powerplant Oral (Jeppesen) Questions with
100% Correct Answers | Latest Version 2024 | Verified
What is the purpose of dynamic dampers on crankshafts? - ✔✔They reduce engine vibration.
What types of bearings are generally found in reciprocating engines? - ✔✔Plain, ball and roller bearings.
Are the connecting rods used in each cylinder of a radial engine the same? Explain. - ✔✔No. Radial
engines use master and articulating rod assemblies.
Name the different types of piston rings. - ✔✔Oil control, compression, and oil scraper.
Where should piston ring gaps be installed relative to each other, and why? - ✔✔Compression ring gaps
should be staggered so that they do not align. This prevents excessive blow-by.
What could result from incorrectly installed piston rings? - ✔✔Excessive oil consumption.
What purpose do oil control rings serve? - ✔✔They regulate the thickness of the oil film on the cylinder
walls.
What is used to help prevent valve surge or floating in an aircraft engine? - ✔✔Two or more springs are
used on each valve.
On engines equipped with hydraulic valve lifters, what should the running valve clearance be? - ✔✔Zero.
What is the purpose of valve overlap? - ✔✔It allows better volumetric efficiency and lowers cylinder
operating temperatures
What indications are given in the event of a leaking or open primer while the engine is running? -
✔✔The engine will not idle properly.
,A cold cylinder is found when troubleshooting a running engine. What does this indicate? - ✔✔No
combustion in that cylinder.
When pulling a propeller through, a hissing sound is heard, indicating valve blow-by. What procedure
should be performed next? - ✔✔A compression check should be performed to identify the faulty
cylinder.
What is the purpose of performing a compression test? - ✔✔To determine if the valves, pistons, and
rings are sealing properly
When an engine is overhauled, how is the total time affected? When an engine is rebuilt, how is its
operating history affected? - ✔✔The total time on the engine must be continued and the time since
major overhaul is entered into the engine log. It the manufacturer rebuilds the engine, it is granted a
zero-time status and is considered to have no previous operating history.
What inspections should be performed after a propeller strike without sudden stoppage? - ✔✔1.Inspect
engine mounts, the crankcase, and the nose section for damage.
2.Inspect the oil and oil filters/screens for metal particles.
3.Inspect the crankshaft or driveshaft for cracks and misalignment.
Name some of the precautions that should be performed prior to engine removal. - ✔✔Disconnect the
battery, turn off the fuel valves, chock the wheels, and if necessary, install a tail stand.
When inspecting a piston, where are cracks most likely to be found? - ✔✔In those areas that are highly
stressed; usually the base of the piston bosses, inside at the junction of the bore and the walls, and the
ring lands.
What does it mean if an engine part is within "serviceable limits"? - ✔✔It means that the part is within
the manufacturer's limits and can be used in an engine (does not require replacement).
, What tools or instruments are used to inspect a cylinder barrel for out-of-roundness? - ✔✔A dial
indicator or an inside micrometer is usually used to measure the top of the cylinder and at the skirt. A
telescopic gauge and micrometer can also be used. Two readings should be taken 90# to each other.
How can a loose stud in an engine crankcase be repaired? - ✔✔Remove the loose stud and inspect the
hole for size and thread condition. It may be necessary to use an oversize stud or Heli-Coil.
What publication is used to check an engine for normal operation? - ✔✔Manufacturer's maintenance
manual.
A weak cylinder is found during a compression check. What must be inspected? - ✔✔The inside of the
cylinder.
What purpose does an oil analysis serve? - ✔✔Metal particles in the oil show normal and abnormal wear
of the engine. This helps in evaluating the engine's internal condition.
What inspections should be performed on an engine that has been in storage? - ✔✔Perform an
inspection to determine if there is any corrosion damage.
Where would a carburetor air temperature bulb be located? - ✔✔In the ram air intake duct.
What is the fuel pressure range on float-type carburetors? - ✔✔3 to 5 psi.
Where is the fuel flow indicating system generally connected within a carbureted reciprocating engine? -
✔✔Between the engine fuel pump and the indicator.
Name the basic components of a fuel flow system. - ✔✔The transmitter and the indicator.
What unit of measure is generally used to indicate fuel flow? - ✔✔Pounds or gallons per hour.
Why is fuel flow monitored? - ✔✔To determine fuel consumption and engine performance.
100% Correct Answers | Latest Version 2024 | Verified
What is the purpose of dynamic dampers on crankshafts? - ✔✔They reduce engine vibration.
What types of bearings are generally found in reciprocating engines? - ✔✔Plain, ball and roller bearings.
Are the connecting rods used in each cylinder of a radial engine the same? Explain. - ✔✔No. Radial
engines use master and articulating rod assemblies.
Name the different types of piston rings. - ✔✔Oil control, compression, and oil scraper.
Where should piston ring gaps be installed relative to each other, and why? - ✔✔Compression ring gaps
should be staggered so that they do not align. This prevents excessive blow-by.
What could result from incorrectly installed piston rings? - ✔✔Excessive oil consumption.
What purpose do oil control rings serve? - ✔✔They regulate the thickness of the oil film on the cylinder
walls.
What is used to help prevent valve surge or floating in an aircraft engine? - ✔✔Two or more springs are
used on each valve.
On engines equipped with hydraulic valve lifters, what should the running valve clearance be? - ✔✔Zero.
What is the purpose of valve overlap? - ✔✔It allows better volumetric efficiency and lowers cylinder
operating temperatures
What indications are given in the event of a leaking or open primer while the engine is running? -
✔✔The engine will not idle properly.
,A cold cylinder is found when troubleshooting a running engine. What does this indicate? - ✔✔No
combustion in that cylinder.
When pulling a propeller through, a hissing sound is heard, indicating valve blow-by. What procedure
should be performed next? - ✔✔A compression check should be performed to identify the faulty
cylinder.
What is the purpose of performing a compression test? - ✔✔To determine if the valves, pistons, and
rings are sealing properly
When an engine is overhauled, how is the total time affected? When an engine is rebuilt, how is its
operating history affected? - ✔✔The total time on the engine must be continued and the time since
major overhaul is entered into the engine log. It the manufacturer rebuilds the engine, it is granted a
zero-time status and is considered to have no previous operating history.
What inspections should be performed after a propeller strike without sudden stoppage? - ✔✔1.Inspect
engine mounts, the crankcase, and the nose section for damage.
2.Inspect the oil and oil filters/screens for metal particles.
3.Inspect the crankshaft or driveshaft for cracks and misalignment.
Name some of the precautions that should be performed prior to engine removal. - ✔✔Disconnect the
battery, turn off the fuel valves, chock the wheels, and if necessary, install a tail stand.
When inspecting a piston, where are cracks most likely to be found? - ✔✔In those areas that are highly
stressed; usually the base of the piston bosses, inside at the junction of the bore and the walls, and the
ring lands.
What does it mean if an engine part is within "serviceable limits"? - ✔✔It means that the part is within
the manufacturer's limits and can be used in an engine (does not require replacement).
, What tools or instruments are used to inspect a cylinder barrel for out-of-roundness? - ✔✔A dial
indicator or an inside micrometer is usually used to measure the top of the cylinder and at the skirt. A
telescopic gauge and micrometer can also be used. Two readings should be taken 90# to each other.
How can a loose stud in an engine crankcase be repaired? - ✔✔Remove the loose stud and inspect the
hole for size and thread condition. It may be necessary to use an oversize stud or Heli-Coil.
What publication is used to check an engine for normal operation? - ✔✔Manufacturer's maintenance
manual.
A weak cylinder is found during a compression check. What must be inspected? - ✔✔The inside of the
cylinder.
What purpose does an oil analysis serve? - ✔✔Metal particles in the oil show normal and abnormal wear
of the engine. This helps in evaluating the engine's internal condition.
What inspections should be performed on an engine that has been in storage? - ✔✔Perform an
inspection to determine if there is any corrosion damage.
Where would a carburetor air temperature bulb be located? - ✔✔In the ram air intake duct.
What is the fuel pressure range on float-type carburetors? - ✔✔3 to 5 psi.
Where is the fuel flow indicating system generally connected within a carbureted reciprocating engine? -
✔✔Between the engine fuel pump and the indicator.
Name the basic components of a fuel flow system. - ✔✔The transmitter and the indicator.
What unit of measure is generally used to indicate fuel flow? - ✔✔Pounds or gallons per hour.
Why is fuel flow monitored? - ✔✔To determine fuel consumption and engine performance.
