ASA Powerplant Oral Questions And
Answers
In what position should the crankshaft be when a magneto is being
timed to the engine? -
correct answer ✅The piston in cylinder 1 should be in the correct
position for ignition to occur. This is normally about 30° before top
dead center on the compression stroke.
What is the purpose of a cold cylinder check? -
correct answer ✅A cold cylinder check determines which cylinder
is not firing. Run the engine for a few minutes at the speed, and on
the magneto, at which it runs roughest. Shut it down and feel the
exhaust stack near the cylinder head. The cylinder with the stack
that is not as hot as the others is the cylinder that has not been
firing.
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.
How can you determine the firing order of an 18-cylinder radial
engine? -
,ASA Powerplant Oral Questions And
Answers
correct answer ✅Begin with cylinder 1, add 11, and 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 are 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 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 line
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? -
correct answer ✅Remove a spark plug from the locked cylinder
and drain all of the oil out. Clean the spark plug and replace it.
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
,ASA Powerplant Oral Questions And
Answers
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 is a 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 aircraft 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
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 no. 1,
, ASA Powerplant Oral Questions And
Answers
set with the hot clearance. When the timing is set, all of the valves
are adjusted to their cold clearance.
What must be inspected to determine the Airworthiness of an
engine installation? -
correct answer ✅The propeller, lubrication system, ignition
system, fuel metering system, cooling system and the exhaust
system.
What checks should be made to determine the proper operation of
a reciprocating engine installation? -
correct answer ✅Idle RPM and mixture, static RPM, propeller pitch
change operation, magneto check, ignition switch safety check, and
carburetor heat check.
Where can you find the correct grade of fuel and amount of engine
lubricating oil for an aircraft engine? -
correct answer ✅In the Type Certificate Data Sheets for the
aircraft.
What are the basic steps in troubleshooting an engine installation?
-
correct answer ✅a. Know how the system should operate. b.
Answers
In what position should the crankshaft be when a magneto is being
timed to the engine? -
correct answer ✅The piston in cylinder 1 should be in the correct
position for ignition to occur. This is normally about 30° before top
dead center on the compression stroke.
What is the purpose of a cold cylinder check? -
correct answer ✅A cold cylinder check determines which cylinder
is not firing. Run the engine for a few minutes at the speed, and on
the magneto, at which it runs roughest. Shut it down and feel the
exhaust stack near the cylinder head. The cylinder with the stack
that is not as hot as the others is the cylinder that has not been
firing.
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.
How can you determine the firing order of an 18-cylinder radial
engine? -
,ASA Powerplant Oral Questions And
Answers
correct answer ✅Begin with cylinder 1, add 11, and 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 are 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 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 line
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? -
correct answer ✅Remove a spark plug from the locked cylinder
and drain all of the oil out. Clean the spark plug and replace it.
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
,ASA Powerplant Oral Questions And
Answers
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 is a 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 aircraft 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
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 no. 1,
, ASA Powerplant Oral Questions And
Answers
set with the hot clearance. When the timing is set, all of the valves
are adjusted to their cold clearance.
What must be inspected to determine the Airworthiness of an
engine installation? -
correct answer ✅The propeller, lubrication system, ignition
system, fuel metering system, cooling system and the exhaust
system.
What checks should be made to determine the proper operation of
a reciprocating engine installation? -
correct answer ✅Idle RPM and mixture, static RPM, propeller pitch
change operation, magneto check, ignition switch safety check, and
carburetor heat check.
Where can you find the correct grade of fuel and amount of engine
lubricating oil for an aircraft engine? -
correct answer ✅In the Type Certificate Data Sheets for the
aircraft.
What are the basic steps in troubleshooting an engine installation?
-
correct answer ✅a. Know how the system should operate. b.
