A&P - Powerplant Oral (Jeppesen)
A&P Powerplant Oral Exam Review (
2025–2026) – Key Topics and Study
Notes
What is the purpose of dynamic dampers on crankshafts? They reduce engine vibration.
What types of bearings are generally found in Plain, ball and roller bearings.
reciprocating engines?
Are the connecting rods used in each cylinder of a radial No. Radial engines use master and articulating rod assemblies.
engine the same? Explain.
Name the different types of piston rings. Oil control, compression, and oil scraper.
Where should piston ring gaps be installed relative to Compression ring gaps should be staggered so that they do not align. This
each other, and why? 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 Two or more springs are used on each valve.
aircraft engine?
On engines equipped with hydraulic valve lifters, what Zero.
should the running valve clearance be?
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 The engine will not idle properly.
open primer while the engine is running?
A cold cylinder is found when troubleshooting a running No combustion in that cylinder.
engine. What does this indicate?
,When pulling a propeller through, a hissing sound is A compression check should be performed to identify the faulty cylinder.
heard, indicating valve blow-by. What procedure should
be performed next?
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 The total time on the engine must be continued and the time since major overhaul
affected? When an engine is rebuilt, how is its operating is entered into the engine log. It the manufacturer rebuilds the engine, it is
history affected? granted a zero-time status and is considered to have no previous operating
history.
What inspections should be performed after a propeller 1. Inspect engine mounts, the crankcase, and the nose section for damage.
strike without sudden stoppage? 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 Disconnect the battery, turn off the fuel valves, chock the wheels, and if
prior to engine removal. necessary, install a tail stand.
When inspecting a piston, where are cracks most likely to In those areas that are highly stressed; usually the base of the piston bosses,
be found? 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 It means that the part is within the manufacturer's limits and can be used in an
limits"? engine (does not require replacement).
What tools or instruments are used to inspect a cylinder A dial indicator or an inside micrometer is usually used to measure the top of the
barrel for out-of-roundness? 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 Remove the loose stud and inspect the hole for size and thread condition. It may
repaired? be necessary to use an oversize stud or Heli-Coil.
What publication is used to check an engine for normal Manufacturer's maintenance manual.
operation?
A weak cylinder is found during a compression check. The inside of the cylinder.
What must be inspected?
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 Perform an inspection to determine if there is any corrosion damage.
has been in storage?
Where would a carburetor air temperature bulb be In the ram air intake duct.
located?
What is the fuel pressure range on float-type 3 to 5 psi.
carburetors?
, Where is the fuel flow indicating system generally Between the engine fuel pump and the indicator.
connected within a carbureted reciprocating engine?
Name the basic components of a fuel flow system. The transmitter and the indicator.
What unit of measure is generally used to indicate fuel Pounds or gallons per hour.
flow?
Why is fuel flow monitored? To determine fuel consumption and engine performance.
What does the manifold gauge indicate and how is it It measures the absolute pressure in the engine manifold and is calibrated in
calibrated? inches of mercury.
What directly controls manifold pressure? Throttle opening and engine rpm.
During engine operation, where should the propeller Low pitch, high r.p.m.
control be set when checking the manifold pressure?
Is the aircraft electrical system required to power a No. A thermocouple is used as the electrical source.
cylinder head temperature gauge?
What are the possible indications of an oil pressure A severe or sudden drop in oil pressure while the oil temperature remains normal
transmitter or indicator malfunction? and the oil supply remains full.
What does a tachometer indicate on a reciprocating Engine r.p.m.
engine?
Where should the thermocouple be installed on a On the hottest cylinder
reciprocating engine using a single probe cylinder head
temperature system?
Explain the main difference and advantage a turbofan A turbofan engine uses a fan to bypass some air around the engine core and to
over turbojet engines. provide thrust. The advantage is that this provides additional thrust without
increasing fuel flow.
Name the major components in a gas turbine engine. Air inlet, compressor section, combustion section, turbine section, exhaust
section, gearbox and accessory section.
What determines the amount of airflow through a turbine The forward speed of the aircraft, compressor speed, and air density.
engine?
Name the two types of compressors commonly used in Axial and centrifugal flow compressors.
turbine engines.
Name two different methods for attaching turbine engine Dovetail-type root
rotor blades to the rotor disks. Bulb-type root
Fir tree-type root.
What is a split compressor system? Also called dual or twin spool compressors, these are connected to the turbine
section with two rotor shafts, one inside the other.
A&P Powerplant Oral Exam Review (
2025–2026) – Key Topics and Study
Notes
What is the purpose of dynamic dampers on crankshafts? They reduce engine vibration.
What types of bearings are generally found in Plain, ball and roller bearings.
reciprocating engines?
Are the connecting rods used in each cylinder of a radial No. Radial engines use master and articulating rod assemblies.
engine the same? Explain.
Name the different types of piston rings. Oil control, compression, and oil scraper.
Where should piston ring gaps be installed relative to Compression ring gaps should be staggered so that they do not align. This
each other, and why? 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 Two or more springs are used on each valve.
aircraft engine?
On engines equipped with hydraulic valve lifters, what Zero.
should the running valve clearance be?
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 The engine will not idle properly.
open primer while the engine is running?
A cold cylinder is found when troubleshooting a running No combustion in that cylinder.
engine. What does this indicate?
,When pulling a propeller through, a hissing sound is A compression check should be performed to identify the faulty cylinder.
heard, indicating valve blow-by. What procedure should
be performed next?
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 The total time on the engine must be continued and the time since major overhaul
affected? When an engine is rebuilt, how is its operating is entered into the engine log. It the manufacturer rebuilds the engine, it is
history affected? granted a zero-time status and is considered to have no previous operating
history.
What inspections should be performed after a propeller 1. Inspect engine mounts, the crankcase, and the nose section for damage.
strike without sudden stoppage? 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 Disconnect the battery, turn off the fuel valves, chock the wheels, and if
prior to engine removal. necessary, install a tail stand.
When inspecting a piston, where are cracks most likely to In those areas that are highly stressed; usually the base of the piston bosses,
be found? 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 It means that the part is within the manufacturer's limits and can be used in an
limits"? engine (does not require replacement).
What tools or instruments are used to inspect a cylinder A dial indicator or an inside micrometer is usually used to measure the top of the
barrel for out-of-roundness? 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 Remove the loose stud and inspect the hole for size and thread condition. It may
repaired? be necessary to use an oversize stud or Heli-Coil.
What publication is used to check an engine for normal Manufacturer's maintenance manual.
operation?
A weak cylinder is found during a compression check. The inside of the cylinder.
What must be inspected?
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 Perform an inspection to determine if there is any corrosion damage.
has been in storage?
Where would a carburetor air temperature bulb be In the ram air intake duct.
located?
What is the fuel pressure range on float-type 3 to 5 psi.
carburetors?
, Where is the fuel flow indicating system generally Between the engine fuel pump and the indicator.
connected within a carbureted reciprocating engine?
Name the basic components of a fuel flow system. The transmitter and the indicator.
What unit of measure is generally used to indicate fuel Pounds or gallons per hour.
flow?
Why is fuel flow monitored? To determine fuel consumption and engine performance.
What does the manifold gauge indicate and how is it It measures the absolute pressure in the engine manifold and is calibrated in
calibrated? inches of mercury.
What directly controls manifold pressure? Throttle opening and engine rpm.
During engine operation, where should the propeller Low pitch, high r.p.m.
control be set when checking the manifold pressure?
Is the aircraft electrical system required to power a No. A thermocouple is used as the electrical source.
cylinder head temperature gauge?
What are the possible indications of an oil pressure A severe or sudden drop in oil pressure while the oil temperature remains normal
transmitter or indicator malfunction? and the oil supply remains full.
What does a tachometer indicate on a reciprocating Engine r.p.m.
engine?
Where should the thermocouple be installed on a On the hottest cylinder
reciprocating engine using a single probe cylinder head
temperature system?
Explain the main difference and advantage a turbofan A turbofan engine uses a fan to bypass some air around the engine core and to
over turbojet engines. provide thrust. The advantage is that this provides additional thrust without
increasing fuel flow.
Name the major components in a gas turbine engine. Air inlet, compressor section, combustion section, turbine section, exhaust
section, gearbox and accessory section.
What determines the amount of airflow through a turbine The forward speed of the aircraft, compressor speed, and air density.
engine?
Name the two types of compressors commonly used in Axial and centrifugal flow compressors.
turbine engines.
Name two different methods for attaching turbine engine Dovetail-type root
rotor blades to the rotor disks. Bulb-type root
Fir tree-type root.
What is a split compressor system? Also called dual or twin spool compressors, these are connected to the turbine
section with two rotor shafts, one inside the other.
