powerplant oral questions With Complete Solutions
in what position should the ignition switch be placed when using
a timing light on the magnetos?
in the Both position
What is the E-gap in magneto timing?
The E-gap angle is the position of the rotating magnet when the
primary current flowing in the magneto coil is the greatest. The
breaker points open when the rotating magnet is in its E-gap
position.
What malfunction in the ignition system would cause an aircraft
reciprocating engine to continue to run after the ignition switch
is placed in the Off position?
the ignition switch is not grounding the magneto primary circuit
what is the function of a float carburetor?
The float carburetor's function is to measure airflow through the
engine induction system and dispense the appropriate amount of
gasoline into the airflow for all engine operating perimeters and
conditions. It must also provide the fuel in a state that is as
vaporized as possible by the time ignition occurs in the engine
cylinders.
what two things are adjusted when setting the idling conditions
on a float carburetor?
1. idling RPM by adjusting the throttle stop
2. idling mixture by adjusting idle needle valve
,what would likely cause a reciprocating engine equipped with a
float carburetor to hesitate momentarily when the throttle is
rapidly advanced from idle to full power?
a malfunctioning accelerator pump
what is a FADEC?
A Full-Authority Digital Electronic Control (FADEC) is a high-
precision digital electronic fuel control that functions during all
engine operations. It includes the Electronic Engine Control
(EEC) and functions with the Flight Management Computer
(FMC) to measure the fuel to the nozzles in such a way that
prevents overshooting of power changes and over-temperature
conditions. FADEC furnishes information to the Engine
Indicating and Crew Alerting System (EICAS).
Does a turbine engine controlled by a FADEC require manual
trimming?
no, this is done by the FEDEC
what are the three most common types of fuel filters?
the micron filter
the wafer screen filter
the plain screen mesh filter
why do some aircraft filters have a relief valve?
If the fuel screen, or filter, becomes clogged, the relief valve will
allow fuel to continue to flow to the engine.
How does a leak appear in an engine exhaust system?
, it normally looks like a gray or black feather-shaped streak
coming from a crack or from a location where components are
not in perfect alignment
how can you check a reciprocating engine exhaust system for
leaks?
pressurize the exhaust system with the discharge from a vacuum
cleaner and wipe a soap solution over all joints and suspect
areas. A leak will cause bubbles to form
How do the components in the exhaust system of a turbocharged
engine allow for expansion and contraction due to heat, and at
the same time prevent leakage?
bellows and ball joints prevent leakage while allowing
contraction and expansion
Should a turbocharged engine be started with the waste gate
open or closed?
open, so as much exhaust as possible will bypass the turbine
what is the primary function of a reciprocating engine exhaust
system?
its main function is to dispose of the gases with complete safety
to the airframe and the occupants of the aircraft. the exhaust
system can perform many useful functions, but its first duty is to
provide protection against the potentially destructive action of
the exhaust gases
what is a short stack exhaust system?
in what position should the ignition switch be placed when using
a timing light on the magnetos?
in the Both position
What is the E-gap in magneto timing?
The E-gap angle is the position of the rotating magnet when the
primary current flowing in the magneto coil is the greatest. The
breaker points open when the rotating magnet is in its E-gap
position.
What malfunction in the ignition system would cause an aircraft
reciprocating engine to continue to run after the ignition switch
is placed in the Off position?
the ignition switch is not grounding the magneto primary circuit
what is the function of a float carburetor?
The float carburetor's function is to measure airflow through the
engine induction system and dispense the appropriate amount of
gasoline into the airflow for all engine operating perimeters and
conditions. It must also provide the fuel in a state that is as
vaporized as possible by the time ignition occurs in the engine
cylinders.
what two things are adjusted when setting the idling conditions
on a float carburetor?
1. idling RPM by adjusting the throttle stop
2. idling mixture by adjusting idle needle valve
,what would likely cause a reciprocating engine equipped with a
float carburetor to hesitate momentarily when the throttle is
rapidly advanced from idle to full power?
a malfunctioning accelerator pump
what is a FADEC?
A Full-Authority Digital Electronic Control (FADEC) is a high-
precision digital electronic fuel control that functions during all
engine operations. It includes the Electronic Engine Control
(EEC) and functions with the Flight Management Computer
(FMC) to measure the fuel to the nozzles in such a way that
prevents overshooting of power changes and over-temperature
conditions. FADEC furnishes information to the Engine
Indicating and Crew Alerting System (EICAS).
Does a turbine engine controlled by a FADEC require manual
trimming?
no, this is done by the FEDEC
what are the three most common types of fuel filters?
the micron filter
the wafer screen filter
the plain screen mesh filter
why do some aircraft filters have a relief valve?
If the fuel screen, or filter, becomes clogged, the relief valve will
allow fuel to continue to flow to the engine.
How does a leak appear in an engine exhaust system?
, it normally looks like a gray or black feather-shaped streak
coming from a crack or from a location where components are
not in perfect alignment
how can you check a reciprocating engine exhaust system for
leaks?
pressurize the exhaust system with the discharge from a vacuum
cleaner and wipe a soap solution over all joints and suspect
areas. A leak will cause bubbles to form
How do the components in the exhaust system of a turbocharged
engine allow for expansion and contraction due to heat, and at
the same time prevent leakage?
bellows and ball joints prevent leakage while allowing
contraction and expansion
Should a turbocharged engine be started with the waste gate
open or closed?
open, so as much exhaust as possible will bypass the turbine
what is the primary function of a reciprocating engine exhaust
system?
its main function is to dispose of the gases with complete safety
to the airframe and the occupants of the aircraft. the exhaust
system can perform many useful functions, but its first duty is to
provide protection against the potentially destructive action of
the exhaust gases
what is a short stack exhaust system?
