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ASA POWERPLANT ORAL EXAM 2 NEWEST 2026 ACTUAL EXAM
WITH COMPLETE QUESTIONS AND CORRECT DETAILED ANSWERS
(100% VERIFIED ANSWERS) |ALREADY GRADED A+| ||PROFESSOR
VERIFIED||
Why is an aircraft reciprocating engine killed by placing the
mixture control in the Cutoff position, rather than by using the
magneto switch - ANSWER-By shutting off the fuel to the
cylinders, the combustion chambers are left full of air with no fuel.
This makes the engine less likely to fire if the propeller is pulled
through with the ignition switch accidentally on.
Where is the fuel from a continuous-flow fuel injection system
discharged - ANSWER-It is discharged through injector nozzles
screwed into the cylinder heads near the intake valves.
In which direction relative to the wind should a turbine-powered
aircraft be positioned when the fuel control is being trimmed -
ANSWER-If the wind velocity is less than 10 miles per hour, it can
be faced in any direction. If the wind velocity is between 10 and
25 MPH, it should be trimmed facing into the wind. The engine
should not be trimmed when the wind velocity is more than 25
MPH.
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What engine parameters are sensed by the fuel control unit of a
turbine engine - ANSWER-Engine RPM, inlet air pressure,
compressor discharge pressure, burner can pressure, and inlet air
temperature.
When does the acceleration system operate on an aircraft
carburetor - ANSWER-When the throttle is suddenly opened.
What is the purpose of the bypass valve in an engine-driven fuel
pump - ANSWER-The bypass valve allows fuel to flow around the
engine-driven pump for starting & for emergency operation if the
engine-driven pump should fail.
On which side of the firewall is the engine fuel shutoff valve
located - ANSWER-The shutoff valve must be on the side of the
firewall away from the engine.
What are three purposes for the boost pumps in an aircraft fuel
system - ANSWER-To provide fuel pressure for starting the
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engine, to pressurize the fuel lines to prevent vapor lock, & to
transfer fuel from one tank to another.
What kind of boost pump is used in most aircraft fuel systems -
ANSWER-Electrically operated centrifugal pumps.
Where does an engine-driven fuel pump direct the excess fuel
from its pressure relief valve - ANSWER-Back to the inlet side of
the pump.
What causes a vapor lock in an aircraft fuel system - ANSWER-
The fuel becomes hot enough that it boils. Vapors are released
from the liquid fuel, & these vapors block the fuel lines so the
liquid fuel cannot flow to the engine.
What is done in most aircraft fuel systems to prevent vapor lock -
ANSWER-Boost pumps in the fuel tank pressurize the fuel in the
lines & force the fuel into the fuel metering system.
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What is meant by a compensated relief valve in an engine-driven
fuel pump - ANSWER-A pressure relief valve that is acted upon
by a diaphragm as well as a spring. Atmospheric pressure acting
on the diaphragm varies the pump discharge pressure so that it
will remain a given amount higher than the pressure of the air
entering the carburetor.
What is the purpose of the pressurizing & dump valve in the fuel
system for a turbine engine - ANSWER-For normal engine
operation, the pressurizing & dump valve acts a flow divider,
directing the fuel into the main or pilot manifold so it will be
discharged from the proper orifice in the duplex fuel nozzle. When
the engine is shut down, the dump function of the valve dumps all
of the fuel from the manifold.
What should be done to an aircraft reciprocating engine if it has
been operated on turbine engine fuel - ANSWER-All of the turbine
fuel should be drained out & the system filled with the proper
grade of aviation gasoline. The engine should be given a
compression check, & all of the cylinders should be inspected
with a borescope. The oil should be drained & the filters carefully
examined. The engine should be given a complete run-up check.
ASA POWERPLANT ORAL EXAM 2 NEWEST 2026 ACTUAL EXAM
WITH COMPLETE QUESTIONS AND CORRECT DETAILED ANSWERS
(100% VERIFIED ANSWERS) |ALREADY GRADED A+| ||PROFESSOR
VERIFIED||
Why is an aircraft reciprocating engine killed by placing the
mixture control in the Cutoff position, rather than by using the
magneto switch - ANSWER-By shutting off the fuel to the
cylinders, the combustion chambers are left full of air with no fuel.
This makes the engine less likely to fire if the propeller is pulled
through with the ignition switch accidentally on.
Where is the fuel from a continuous-flow fuel injection system
discharged - ANSWER-It is discharged through injector nozzles
screwed into the cylinder heads near the intake valves.
In which direction relative to the wind should a turbine-powered
aircraft be positioned when the fuel control is being trimmed -
ANSWER-If the wind velocity is less than 10 miles per hour, it can
be faced in any direction. If the wind velocity is between 10 and
25 MPH, it should be trimmed facing into the wind. The engine
should not be trimmed when the wind velocity is more than 25
MPH.
,2|Page
What engine parameters are sensed by the fuel control unit of a
turbine engine - ANSWER-Engine RPM, inlet air pressure,
compressor discharge pressure, burner can pressure, and inlet air
temperature.
When does the acceleration system operate on an aircraft
carburetor - ANSWER-When the throttle is suddenly opened.
What is the purpose of the bypass valve in an engine-driven fuel
pump - ANSWER-The bypass valve allows fuel to flow around the
engine-driven pump for starting & for emergency operation if the
engine-driven pump should fail.
On which side of the firewall is the engine fuel shutoff valve
located - ANSWER-The shutoff valve must be on the side of the
firewall away from the engine.
What are three purposes for the boost pumps in an aircraft fuel
system - ANSWER-To provide fuel pressure for starting the
,3|Page
engine, to pressurize the fuel lines to prevent vapor lock, & to
transfer fuel from one tank to another.
What kind of boost pump is used in most aircraft fuel systems -
ANSWER-Electrically operated centrifugal pumps.
Where does an engine-driven fuel pump direct the excess fuel
from its pressure relief valve - ANSWER-Back to the inlet side of
the pump.
What causes a vapor lock in an aircraft fuel system - ANSWER-
The fuel becomes hot enough that it boils. Vapors are released
from the liquid fuel, & these vapors block the fuel lines so the
liquid fuel cannot flow to the engine.
What is done in most aircraft fuel systems to prevent vapor lock -
ANSWER-Boost pumps in the fuel tank pressurize the fuel in the
lines & force the fuel into the fuel metering system.
, 4|Page
What is meant by a compensated relief valve in an engine-driven
fuel pump - ANSWER-A pressure relief valve that is acted upon
by a diaphragm as well as a spring. Atmospheric pressure acting
on the diaphragm varies the pump discharge pressure so that it
will remain a given amount higher than the pressure of the air
entering the carburetor.
What is the purpose of the pressurizing & dump valve in the fuel
system for a turbine engine - ANSWER-For normal engine
operation, the pressurizing & dump valve acts a flow divider,
directing the fuel into the main or pilot manifold so it will be
discharged from the proper orifice in the duplex fuel nozzle. When
the engine is shut down, the dump function of the valve dumps all
of the fuel from the manifold.
What should be done to an aircraft reciprocating engine if it has
been operated on turbine engine fuel - ANSWER-All of the turbine
fuel should be drained out & the system filled with the proper
grade of aviation gasoline. The engine should be given a
compression check, & all of the cylinders should be inspected
with a borescope. The oil should be drained & the filters carefully
examined. The engine should be given a complete run-up check.
