ASA AMT Powerplant Oral & Practical
Examination – [Study Material, Q&A &
Certification Review] (Updated | LATEST
2026 PDF)
RECIPROCATING ENGINES - ANSWER-RECIPROCATING ENGINES
What are the basic types or configurations of reciprocating engines? - ANSWER-
Inline, Opposed, V-Type, and Radial
In what position should the crankshaft be when a magneto is being timed to the
engine? - 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? - 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? - ANSWER-Oil has drained past the
piston rings and filled the combustion chamber of cylinders that are below the
center of 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? - 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? - ANSWER-Intake,
Compression, Power, and Exhaust
What are the two main causes of a cylinder having low compression? - ANSWER-
Piston rings not seating or broken, and valves not seating or burned.
What is a low-tension ignition system? - 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.
What are some advantages of a horizontally opposed engine? - 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? -
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? - 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? - ANSWER-Most horizontally opposed engines have 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? -
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? - 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? - 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? - ANSWER-Spray a preservative
oil inside the cylinders and replace the spark plugs with desiccant plugs.
, What is the formula for calculating indicated horsepower on a 4-stroke engine? -
ANSWER-Indicated Horsepower = (PLANK)/33,000
Where:
P = Indicated mean effective pressure, in psi
L = Length of stroke, in feet or in fractions of a foot
A = Area of the piston head or cross-sectional area of the cylinder, in square
inches
N = Number of power strokes per minute: RPM/2
K = Number of cylinders
What is specific fuel consumption (SFC)? - ANSWER-SFC is a measure of the
economical use of fuel, which is the fuel weight in pounds per hour per
horsepower:
SFC = (pounds fuel/hour)/horsepower
What must be inspected to determine the airworthiness of an engine installation?
- ANSWER-The propeller, lubrication system, ignition system, fuel metering
system, cooling system, and the exhaust system.
Where can you find the correct grade of fuel and the amount of engine lubricating
oil for an aircraft engine? - ANSWER-In the Type Certificate Data Sheets for the
aircraft.
What are the basic steps in troubleshooting an engine installation? - ANSWER-a.
Know how the system should operate.
Examination – [Study Material, Q&A &
Certification Review] (Updated | LATEST
2026 PDF)
RECIPROCATING ENGINES - ANSWER-RECIPROCATING ENGINES
What are the basic types or configurations of reciprocating engines? - ANSWER-
Inline, Opposed, V-Type, and Radial
In what position should the crankshaft be when a magneto is being timed to the
engine? - 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? - 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? - ANSWER-Oil has drained past the
piston rings and filled the combustion chamber of cylinders that are below the
center of 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? - 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? - ANSWER-Intake,
Compression, Power, and Exhaust
What are the two main causes of a cylinder having low compression? - ANSWER-
Piston rings not seating or broken, and valves not seating or burned.
What is a low-tension ignition system? - 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.
What are some advantages of a horizontally opposed engine? - 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? -
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? - 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? - ANSWER-Most horizontally opposed engines have 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? -
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? - 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? - 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? - ANSWER-Spray a preservative
oil inside the cylinders and replace the spark plugs with desiccant plugs.
, What is the formula for calculating indicated horsepower on a 4-stroke engine? -
ANSWER-Indicated Horsepower = (PLANK)/33,000
Where:
P = Indicated mean effective pressure, in psi
L = Length of stroke, in feet or in fractions of a foot
A = Area of the piston head or cross-sectional area of the cylinder, in square
inches
N = Number of power strokes per minute: RPM/2
K = Number of cylinders
What is specific fuel consumption (SFC)? - ANSWER-SFC is a measure of the
economical use of fuel, which is the fuel weight in pounds per hour per
horsepower:
SFC = (pounds fuel/hour)/horsepower
What must be inspected to determine the airworthiness of an engine installation?
- ANSWER-The propeller, lubrication system, ignition system, fuel metering
system, cooling system, and the exhaust system.
Where can you find the correct grade of fuel and the amount of engine lubricating
oil for an aircraft engine? - ANSWER-In the Type Certificate Data Sheets for the
aircraft.
What are the basic steps in troubleshooting an engine installation? - ANSWER-a.
Know how the system should operate.
