ASA AMT Powerplant Oral and Practical
O&P Exam Questions And Answers
RECIPROCATING ENGINES -
correct answer ✅RECIPROCATING ENGINES
What are the basic types or configurations of reciprocating
engines? -
correct answer ✅Inline, Opposed, V-Type, and Radial
In what position should the crankshaft be when a magneto is being
timed to the engine? -
correct answer ✅The piston in cylinder number 1 should be in the
correct position for ignition to occur. This is normally about 30
degrees before top center on the compression stroke.
What is checked on engine runup to determine the operational
condition of the engine? -
correct answer ✅Idling RPM and manifold pressure, engine
acceleration, maximum static RPM and manifold pressure, magneto
drop, ignition switch safety check, propeller pitch change propeller
feathering, oil pressure, fuel pressure, and fuel flow.
What is hydraulic lock in an aircraft engine? -
correct answer ✅Oil has drained past the piston rings and filled
the combustion chamber of cylinders that are below the center of
,ASA AMT Powerplant Oral and Practical
O&P Exam Questions And Answers
the engine. If the crankshaft is turned over with this oil in the
cylinder it will lock, and there is a probability that the piston,
cylinder, or connecting rod will be damaged.
How is a hydraulic lock removed from an aircraft engine? -
correct answer ✅Remove a spark plug from the locked cylinder
and drain all of the oil out. Clean the sprak plug and replace it.
What are the strokes of a 4-stroke reciprocating engine? -
correct answer ✅Intake, Compression, Power, and Exhaust
What are the two main causes of a cylinder having low
compression? -
correct answer ✅Piston rings not seating or broken, and valves not
seating or burned.
What is a low-tension ignition system? -
correct answer ✅It is an ignition system using a magneto with a
brush-type distributor and a coil that has no secondary wiring. Low
voltage is directed from the magneto to a transformer mounted on
the cylinder head. Here the low voltage is boosted to a high voltage
and is directed through a very short high-tension lead to a spark
plug. There is one transformer for each spark plug.
,ASA AMT Powerplant Oral and Practical
O&P Exam Questions And Answers
What are some advantages of a horizontally opposed engine? -
correct answer ✅Low power-to-weight ratio, ideal for installation
on aircraft wings, and low vibration characteristics.
How can you determine the firing order of an 18-cylinder radial
engine? -
correct answer ✅Begin with cylinder 1, and add 11 or subtract 7,
whichever will keep the numbers between 1 and 18. 1-12-5-16-9-2-
13-6-17-10-3-14-7-18-11-4-15-8.
What is aa floating cam ring on a large radial engine? -
correct answer ✅It is a cam ring that rides on a shelf-type bearing
with a large amount of clearance between the bearing and the ring.
When adjusting the valves on an engine with a floating cam ring,
the pressure of the valve springs on the opposite side of the engine
must be removed so the cam ring will be tight against the bearing
for the valves being adjusted.
Why is valve clearance adjusted on radial engines, but not on most
horizontally opposed engines? -
correct answer ✅Most horizontally opposed engines have
, ASA AMT Powerplant Oral and Practical
O&P Exam Questions And Answers
hydraulic valve lifters that keep all of the clearance out of the valve
train. Radial engines have solid lifters.
Why are both the hot and cold valve clearances given for most
radial engines? -
correct answer ✅The hot clearance is given for valve timing
purposes. The timing is adjusted with the valves in cylinder number
one, set with the hot clearance. When the timing is set, all of the
valves are adjusted to their cold clearance.
Why is it important to preserve engines that will not be operated
for an extended period of time? -
correct answer ✅Moisture will accumulate in the engine, initiating
the corrosion process which can ruin the engine.
Preservation for temporary storage is valid for engines that will be
out of service for how many days? -
correct answer ✅30 to 90 days.
What should be done to the cylinders to protect them from rust
and corrosion when preparing the engine for long-time storage? -
correct answer ✅Spray a preservative oil inside the cylinders and
replace the spark plugs with desiccant plugs.
O&P Exam Questions And Answers
RECIPROCATING ENGINES -
correct answer ✅RECIPROCATING ENGINES
What are the basic types or configurations of reciprocating
engines? -
correct answer ✅Inline, Opposed, V-Type, and Radial
In what position should the crankshaft be when a magneto is being
timed to the engine? -
correct answer ✅The piston in cylinder number 1 should be in the
correct position for ignition to occur. This is normally about 30
degrees before top center on the compression stroke.
What is checked on engine runup to determine the operational
condition of the engine? -
correct answer ✅Idling RPM and manifold pressure, engine
acceleration, maximum static RPM and manifold pressure, magneto
drop, ignition switch safety check, propeller pitch change propeller
feathering, oil pressure, fuel pressure, and fuel flow.
What is hydraulic lock in an aircraft engine? -
correct answer ✅Oil has drained past the piston rings and filled
the combustion chamber of cylinders that are below the center of
,ASA AMT Powerplant Oral and Practical
O&P Exam Questions And Answers
the engine. If the crankshaft is turned over with this oil in the
cylinder it will lock, and there is a probability that the piston,
cylinder, or connecting rod will be damaged.
How is a hydraulic lock removed from an aircraft engine? -
correct answer ✅Remove a spark plug from the locked cylinder
and drain all of the oil out. Clean the sprak plug and replace it.
What are the strokes of a 4-stroke reciprocating engine? -
correct answer ✅Intake, Compression, Power, and Exhaust
What are the two main causes of a cylinder having low
compression? -
correct answer ✅Piston rings not seating or broken, and valves not
seating or burned.
What is a low-tension ignition system? -
correct answer ✅It is an ignition system using a magneto with a
brush-type distributor and a coil that has no secondary wiring. Low
voltage is directed from the magneto to a transformer mounted on
the cylinder head. Here the low voltage is boosted to a high voltage
and is directed through a very short high-tension lead to a spark
plug. There is one transformer for each spark plug.
,ASA AMT Powerplant Oral and Practical
O&P Exam Questions And Answers
What are some advantages of a horizontally opposed engine? -
correct answer ✅Low power-to-weight ratio, ideal for installation
on aircraft wings, and low vibration characteristics.
How can you determine the firing order of an 18-cylinder radial
engine? -
correct answer ✅Begin with cylinder 1, and add 11 or subtract 7,
whichever will keep the numbers between 1 and 18. 1-12-5-16-9-2-
13-6-17-10-3-14-7-18-11-4-15-8.
What is aa floating cam ring on a large radial engine? -
correct answer ✅It is a cam ring that rides on a shelf-type bearing
with a large amount of clearance between the bearing and the ring.
When adjusting the valves on an engine with a floating cam ring,
the pressure of the valve springs on the opposite side of the engine
must be removed so the cam ring will be tight against the bearing
for the valves being adjusted.
Why is valve clearance adjusted on radial engines, but not on most
horizontally opposed engines? -
correct answer ✅Most horizontally opposed engines have
, ASA AMT Powerplant Oral and Practical
O&P Exam Questions And Answers
hydraulic valve lifters that keep all of the clearance out of the valve
train. Radial engines have solid lifters.
Why are both the hot and cold valve clearances given for most
radial engines? -
correct answer ✅The hot clearance is given for valve timing
purposes. The timing is adjusted with the valves in cylinder number
one, set with the hot clearance. When the timing is set, all of the
valves are adjusted to their cold clearance.
Why is it important to preserve engines that will not be operated
for an extended period of time? -
correct answer ✅Moisture will accumulate in the engine, initiating
the corrosion process which can ruin the engine.
Preservation for temporary storage is valid for engines that will be
out of service for how many days? -
correct answer ✅30 to 90 days.
What should be done to the cylinders to protect them from rust
and corrosion when preparing the engine for long-time storage? -
correct answer ✅Spray a preservative oil inside the cylinders and
replace the spark plugs with desiccant plugs.
