POWERPLANT ASA ORAL Exam Questions with Correct Answers 100% Verified By Experts|
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1. What are the basic types or configurations of reciprocating engines? (AM.III.A.K1) Inline,
opposed, v-type, and radial.
2. In what position should the crankshaft be when a magneto is being timed to the engine?
(AM.III.A.K2) The piston in cylinder number 1 should be in the correct position for ignition to
occur. This is normally about 30° before top center on the compression stroke.
3. What is checked on engine runup to determine the operational condition of the engine?
(AM.III.A.K2) 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.
4. What is a hydraulic lock in an aircraft engine? (AM.III.A.K3) 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.
5. How is a hydraulic lock removed from an aircraft engine? (AM.III.A.K3) Remove a spark
plug from the locked cylinder and drain all the oil out. Clean the spark plug and replace it.
6. What are the strokes of a 4-stroke reciprocating engine? (AM.III.A.K3) Intake,
compression, power, and exhaust.
7. What are two main causes of a cylinder having low compression? (AM.III.A.K4) Piston
rings not seating or broken, and valves not seating or burned.
8. What is a low-tension ignition system? (AM.III.A.K4) 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
the spark plug. There is one transformer for each spark plug.
9. What are some advantages of a horizontally opposed engine? (AM.III.A.K4) Low power-
to-weight ratio, ideal for installation on aircraft wings, and low vibration characteristics.
10. How can you determine the firing order of an 18-cylinder radial engine? (AM.III.A.K5)
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.
11. What is a floating cam ring on a large radial engine? (AM.III.A.K5) 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.
12. Why is valve clearance adjusted on radial engines, but not on most horizontally opposed
engines? (AM.III.A.K5) Most horizontally opposed engines have hydraulic valve lifters that
keep all of the clearance out of the valve train. Radial engines have solid lifters.
13. Why are both the hot and cold valve clearances given for most radial engines? (AM.III.A.K5)
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.
14. Why is it important to preserve engines that will not be operated for an extended period of
time? (AM.III.A.K6) Moisture will accumulate in the engine, initiating the corrosion process
which can ruin the engine.
15. Preservation for temporary storage is valid for engines that will be out of service for how
many days? (AM.III.A.K6) 30 to 90 days.
,16. What should be done to the cylinders to protect them from rust and corrosion when
preparing the engine for long-time storage? (AM.III.A.K6) Spray a preservative oil inside the
cylinders and replace the spark plugs with desiccant plugs.
17. What is the formula for calculating indicated horsepower on a 4-stroke engine?
(AM.III.A.K7) Where:
P = Indicated mean effective pressure, in psi
L = Length of the 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
18. What is specific fuel consumption (SFC)? (AM.III.A.K7) SFC is a measure of the
economical use of fuel, which is the fuel weight in pounds per hour per horsepower:
19. What must be inspected to determine the airworthiness of an engine installation?
(AM.III.A.K8) The propeller, lubrication system, ignition system, fuel metering system,
cooling system, and the exhaust system.
20. Where can you find the correct grade of fuel and amount of engine lubricating oil for an
aircraft engine? (AM.III.A.K8) In the Type Certificate Data Sheets for the aircraft.
21. What are the basic steps in troubleshooting an engine installation? (AM.III.A.K8) a. Know
how the system should operate.
b. Observe how the system is operating.
c. Divide the system into smaller parts to find the trouble.
d. Look for the obvious problems first.
, 22. Where do you find instructions for removing an engine from an aircraft? (AM.III.A.K8) In
the aircraft maintenance manual.
23. What must normally be done to a nose-wheel airplane before removing an engine?
(AM.III.A.K8) The tail of the airplane must be supported.
24. What should be used to cover the ends of fuel and oil lines that have been disconnected
from the engine? (AM.III.A.K8) The correct plugs or caps. Never cover the end of a line with
tape.
25. What is meant by a QEC engine assembly? (AM.III.A.K8) An engine that has been
prepared for a quick engine change. The engine is on its mount and all of the accessories are
installed. A minimum of time is required to change engines. All that is needed is for the
controls, wiring, and fluid lines to be connected to the firewall.
26. What is meant by rigging the engine controls so they have some "cushion"? (AM.III.A.K8)
The control on the engine component must contact its stop before the control handle in the
flight deck reaches its stop. This causes the control handle to spring back a slight amount when
it is moved to the extent of its travel.
27. What are two ways of pre-oiling an engine? (AM.III.A.K8) a. Before the spark plugs are
installed and after the oil tank or sump is filled, turn the engine over with the starter until oil
runs out of the fitting to which the oil pressure gauge connects.
b. Use a pre-oiler tank. Air pressure forces oil through all of the passages until some of it flows
from the oil pressure gauge fitting
28. What checks should be made to determine the proper operation of a reciprocating engine
installation? (AM.III.A.K9) Idle RPM and mixture, static RPM, propeller pitch change
operation, magneto check, ignition switch safety check, and carburetor heat check.
29. What is the purpose of a cold cylinder check? (AM.III.A.K9) A cold cylinder check
determines which cylinder is not firing. Run the engine for a few minutes at the speed, and on
Latest Update Guaranteed Success
1. What are the basic types or configurations of reciprocating engines? (AM.III.A.K1) Inline,
opposed, v-type, and radial.
2. In what position should the crankshaft be when a magneto is being timed to the engine?
(AM.III.A.K2) The piston in cylinder number 1 should be in the correct position for ignition to
occur. This is normally about 30° before top center on the compression stroke.
3. What is checked on engine runup to determine the operational condition of the engine?
(AM.III.A.K2) 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.
4. What is a hydraulic lock in an aircraft engine? (AM.III.A.K3) 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.
5. How is a hydraulic lock removed from an aircraft engine? (AM.III.A.K3) Remove a spark
plug from the locked cylinder and drain all the oil out. Clean the spark plug and replace it.
6. What are the strokes of a 4-stroke reciprocating engine? (AM.III.A.K3) Intake,
compression, power, and exhaust.
7. What are two main causes of a cylinder having low compression? (AM.III.A.K4) Piston
rings not seating or broken, and valves not seating or burned.
8. What is a low-tension ignition system? (AM.III.A.K4) 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
the spark plug. There is one transformer for each spark plug.
9. What are some advantages of a horizontally opposed engine? (AM.III.A.K4) Low power-
to-weight ratio, ideal for installation on aircraft wings, and low vibration characteristics.
10. How can you determine the firing order of an 18-cylinder radial engine? (AM.III.A.K5)
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.
11. What is a floating cam ring on a large radial engine? (AM.III.A.K5) 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.
12. Why is valve clearance adjusted on radial engines, but not on most horizontally opposed
engines? (AM.III.A.K5) Most horizontally opposed engines have hydraulic valve lifters that
keep all of the clearance out of the valve train. Radial engines have solid lifters.
13. Why are both the hot and cold valve clearances given for most radial engines? (AM.III.A.K5)
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.
14. Why is it important to preserve engines that will not be operated for an extended period of
time? (AM.III.A.K6) Moisture will accumulate in the engine, initiating the corrosion process
which can ruin the engine.
15. Preservation for temporary storage is valid for engines that will be out of service for how
many days? (AM.III.A.K6) 30 to 90 days.
,16. What should be done to the cylinders to protect them from rust and corrosion when
preparing the engine for long-time storage? (AM.III.A.K6) Spray a preservative oil inside the
cylinders and replace the spark plugs with desiccant plugs.
17. What is the formula for calculating indicated horsepower on a 4-stroke engine?
(AM.III.A.K7) Where:
P = Indicated mean effective pressure, in psi
L = Length of the 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
18. What is specific fuel consumption (SFC)? (AM.III.A.K7) SFC is a measure of the
economical use of fuel, which is the fuel weight in pounds per hour per horsepower:
19. What must be inspected to determine the airworthiness of an engine installation?
(AM.III.A.K8) The propeller, lubrication system, ignition system, fuel metering system,
cooling system, and the exhaust system.
20. Where can you find the correct grade of fuel and amount of engine lubricating oil for an
aircraft engine? (AM.III.A.K8) In the Type Certificate Data Sheets for the aircraft.
21. What are the basic steps in troubleshooting an engine installation? (AM.III.A.K8) a. Know
how the system should operate.
b. Observe how the system is operating.
c. Divide the system into smaller parts to find the trouble.
d. Look for the obvious problems first.
, 22. Where do you find instructions for removing an engine from an aircraft? (AM.III.A.K8) In
the aircraft maintenance manual.
23. What must normally be done to a nose-wheel airplane before removing an engine?
(AM.III.A.K8) The tail of the airplane must be supported.
24. What should be used to cover the ends of fuel and oil lines that have been disconnected
from the engine? (AM.III.A.K8) The correct plugs or caps. Never cover the end of a line with
tape.
25. What is meant by a QEC engine assembly? (AM.III.A.K8) An engine that has been
prepared for a quick engine change. The engine is on its mount and all of the accessories are
installed. A minimum of time is required to change engines. All that is needed is for the
controls, wiring, and fluid lines to be connected to the firewall.
26. What is meant by rigging the engine controls so they have some "cushion"? (AM.III.A.K8)
The control on the engine component must contact its stop before the control handle in the
flight deck reaches its stop. This causes the control handle to spring back a slight amount when
it is moved to the extent of its travel.
27. What are two ways of pre-oiling an engine? (AM.III.A.K8) a. Before the spark plugs are
installed and after the oil tank or sump is filled, turn the engine over with the starter until oil
runs out of the fitting to which the oil pressure gauge connects.
b. Use a pre-oiler tank. Air pressure forces oil through all of the passages until some of it flows
from the oil pressure gauge fitting
28. What checks should be made to determine the proper operation of a reciprocating engine
installation? (AM.III.A.K9) Idle RPM and mixture, static RPM, propeller pitch change
operation, magneto check, ignition switch safety check, and carburetor heat check.
29. What is the purpose of a cold cylinder check? (AM.III.A.K9) A cold cylinder check
determines which cylinder is not firing. Run the engine for a few minutes at the speed, and on
