Powerplant oral Questions and Answers
what procedure should be followed when valve
blow-by is indicated by a hissing sound on a What are the purpose of oil control rings? -
reciprocating engine when pulling the propeller -Oil control rings regulate the thickness of
through? - -Perform a cylinder the oil film on the cylinder wall
compression test to identify the faulty cylinder
What types of bearings are in general use in
What is the running valve clearance on engines reciprocating engines? - -Plain, ball and
equipped with hydraulic valve lifters - -Zero roller
When troubleshooting a running engine Where are cracks most likely to be found in a
malfunction. what does a cold cylinder indicate? - piston? - -Highly stressed areas, the base
-Lack of combustion in that cylinder of the pin bosses, inside at the junction of the
head and walls. and the ring lands
What factors about the condition of an engine
can be learned by studying the results of a How are piston gaps installed relative to each
compression test? - -The results of a other on a piston, and why? - -
compression test determine if the valves, piston Compression ring gaps should be installed in
rings, and pistons are adequately sealing staggered positions around the piston in order to
prevent excessive blow-by
What should be done to repair a loose stud in an
engine crankcase? - -Remove the loose What is the purpose of valve overlap? - -It
stud, and inspect the hole for size and the permits better volumetric efficiency and lowers
condition of the threads. It may be neccessary to the cylinder operating temperature
use a suitable oversize stud
What is the purpose of crankshaft dynamic
How is a cylinder barrel inspected for it of dampers? - -To reduce engine vibration
roundness? - -A Dial indicator can be used
to measure at the top of the cylinder and also at
the skirt. 2 readings should be taken, 90° to each What is meant when it is said that an engine part
other is within "serviceable limits"? - -It will not
likely wear to a point of causing engine failure
within the next time between overhaul interval
What types of connecting rods are commonly
found in radial engines? - -Master and
articulated rod assemblies Name at least one part of an inspection that
should be made after a propeller strike (not
sudden stop) - -inspect the engine mounts,
What are the different types of piston rings? - crankcase, and nose section for damage
-Compression, oil control and oil scrapper
inspect the oil and oil screens/filters for metal
, Powerplant oral Questions and Answers
particles What determines the amount of air passing
through a turbine engine? - -Compressor
inspect the propeller drive shaft or crankshaft for speed, forward soeed of the aircraft and air
misalignment density
What are some of the precautions to be What are the 2 principal types of compressors
observed when preparing an aircraft for engine currently used in turbine engines? - -
removal? - -Disconnect the battery, chock Centrifugal and axial flow
the wheels, install a tail stand (if needed), and
turn off the fuel valves
How are turbine enginenrotor blades attached to
rotor disks? - -Bulb-type root, fir tree-type
What is an indication that a primer is leaking or is root, or dovetail-type root
open during engine operation? - -The
engine will not idle properly
Name at least 3 types of combustion chamber
sections? - -Can, annular, Can-annular and
What may be the result of incorrect installation of reverse flow annular
piston rings? - -Excessive oil consumption
What is the purpose of the interconnect tubes
What are some indications of induction system attached between can-type combustion
leakage? - -Low power and uneven chambers? - -Flame propagation during
running starting
When an engine is rebuilt by the manufacturer, What prevents burning of combustion chambers?
how is its operating history affected? - -A - -Cooling air along the inside of the liner
rebuilt engine is considered to have no previous
operating history and can therefore be issued a
zero-time record What is a unique feature of a split (dual)
compressor system? - -2 rotor shafts. one
inside the other
What is used in an aircraft engine to help prevent
valve surge or float from occurring? - -2 or
more springs on each valve What are carbon sralsbused for in turbine
engines? - -As oil seals for the rotor shaft
bearings
What are the major components of a typical gas
turbine engine? - -An air inlet, compressor
section, combustion section, turbine section, What are the desired effects of turbine engine
exhaust section and accessory section compressor field cleaning? - -Removal of
contaminant deposits from interior engine
surfaces, and improved engine performance
, Powerplant oral Questions and Answers
What may be the indications if a turbojet or
What is the main operating difference between turbofan engine is out of trim? - -High EGT
turbofan and turbojet engines? - -The air at the target engine pressure ratio for take off
that flows through the fan section of a turbofan power
engine bypasses, or flows around the outside of
the core engine instead of through it
What would the possible cause be for a turbojet
or turbofan engine having high EGT, low rpm,
What methods are commonly used to accomplish and high fuel flow at all engine pressure ratio
turbine engine compressor field cleaning? - settings? - -Possible turbine damage or
-Fluid wash and abrasive grit blast loss of turbine efficiency
Name an advantage of a turbofan over a What functions need to be accomplished in order
turbojet? - -Additional thrust without to prepare an engine for a 100-hour inspection? -
increasing fuel flow -Remove cowling and clean
What are the functions of axial flow turbine How may an engine be visually identified? -
nozzles? - -They prepare the mass airflow -By the engine data plate
for driving the turbine rotor and deflect the gases
to a specific angle
What may be used as a guide for 100-hour
inspections on aircraft engines? - -14 CFR
What are some ways of relieving thermal stress part 43 appendix D
on a turbine disk? - -By directing bleed air
on to the face of the disk, or by the grooving in
the turbine disk What additional inspection must be performed if a
cylinder compression is weak? - -An
internal cylinder inspection
What type of compressor blade damage may be
found when inspecting compressor blades? -
-dents, galling, pitting, cracks, scratches, Name at least one place where engine operating
burrs, burns, and gouges limitations may be found - -Type certificate
data sheet, Engine specification, Engine manual,
Aircraft manufacturers maintenance manual
What is used to mark both hot and cold section
parts for repair? - -Layout dye, commercial
felt tip marker, or chalk How does an oil analysis program help to
evaluate the internal condition of an engine? -
-By identifying each wear metal and the
What is the effect of relative humidity on turbojet quantity present in the oil
or turbofan power? - -Negligible
what procedure should be followed when valve
blow-by is indicated by a hissing sound on a What are the purpose of oil control rings? -
reciprocating engine when pulling the propeller -Oil control rings regulate the thickness of
through? - -Perform a cylinder the oil film on the cylinder wall
compression test to identify the faulty cylinder
What types of bearings are in general use in
What is the running valve clearance on engines reciprocating engines? - -Plain, ball and
equipped with hydraulic valve lifters - -Zero roller
When troubleshooting a running engine Where are cracks most likely to be found in a
malfunction. what does a cold cylinder indicate? - piston? - -Highly stressed areas, the base
-Lack of combustion in that cylinder of the pin bosses, inside at the junction of the
head and walls. and the ring lands
What factors about the condition of an engine
can be learned by studying the results of a How are piston gaps installed relative to each
compression test? - -The results of a other on a piston, and why? - -
compression test determine if the valves, piston Compression ring gaps should be installed in
rings, and pistons are adequately sealing staggered positions around the piston in order to
prevent excessive blow-by
What should be done to repair a loose stud in an
engine crankcase? - -Remove the loose What is the purpose of valve overlap? - -It
stud, and inspect the hole for size and the permits better volumetric efficiency and lowers
condition of the threads. It may be neccessary to the cylinder operating temperature
use a suitable oversize stud
What is the purpose of crankshaft dynamic
How is a cylinder barrel inspected for it of dampers? - -To reduce engine vibration
roundness? - -A Dial indicator can be used
to measure at the top of the cylinder and also at
the skirt. 2 readings should be taken, 90° to each What is meant when it is said that an engine part
other is within "serviceable limits"? - -It will not
likely wear to a point of causing engine failure
within the next time between overhaul interval
What types of connecting rods are commonly
found in radial engines? - -Master and
articulated rod assemblies Name at least one part of an inspection that
should be made after a propeller strike (not
sudden stop) - -inspect the engine mounts,
What are the different types of piston rings? - crankcase, and nose section for damage
-Compression, oil control and oil scrapper
inspect the oil and oil screens/filters for metal
, Powerplant oral Questions and Answers
particles What determines the amount of air passing
through a turbine engine? - -Compressor
inspect the propeller drive shaft or crankshaft for speed, forward soeed of the aircraft and air
misalignment density
What are some of the precautions to be What are the 2 principal types of compressors
observed when preparing an aircraft for engine currently used in turbine engines? - -
removal? - -Disconnect the battery, chock Centrifugal and axial flow
the wheels, install a tail stand (if needed), and
turn off the fuel valves
How are turbine enginenrotor blades attached to
rotor disks? - -Bulb-type root, fir tree-type
What is an indication that a primer is leaking or is root, or dovetail-type root
open during engine operation? - -The
engine will not idle properly
Name at least 3 types of combustion chamber
sections? - -Can, annular, Can-annular and
What may be the result of incorrect installation of reverse flow annular
piston rings? - -Excessive oil consumption
What is the purpose of the interconnect tubes
What are some indications of induction system attached between can-type combustion
leakage? - -Low power and uneven chambers? - -Flame propagation during
running starting
When an engine is rebuilt by the manufacturer, What prevents burning of combustion chambers?
how is its operating history affected? - -A - -Cooling air along the inside of the liner
rebuilt engine is considered to have no previous
operating history and can therefore be issued a
zero-time record What is a unique feature of a split (dual)
compressor system? - -2 rotor shafts. one
inside the other
What is used in an aircraft engine to help prevent
valve surge or float from occurring? - -2 or
more springs on each valve What are carbon sralsbused for in turbine
engines? - -As oil seals for the rotor shaft
bearings
What are the major components of a typical gas
turbine engine? - -An air inlet, compressor
section, combustion section, turbine section, What are the desired effects of turbine engine
exhaust section and accessory section compressor field cleaning? - -Removal of
contaminant deposits from interior engine
surfaces, and improved engine performance
, Powerplant oral Questions and Answers
What may be the indications if a turbojet or
What is the main operating difference between turbofan engine is out of trim? - -High EGT
turbofan and turbojet engines? - -The air at the target engine pressure ratio for take off
that flows through the fan section of a turbofan power
engine bypasses, or flows around the outside of
the core engine instead of through it
What would the possible cause be for a turbojet
or turbofan engine having high EGT, low rpm,
What methods are commonly used to accomplish and high fuel flow at all engine pressure ratio
turbine engine compressor field cleaning? - settings? - -Possible turbine damage or
-Fluid wash and abrasive grit blast loss of turbine efficiency
Name an advantage of a turbofan over a What functions need to be accomplished in order
turbojet? - -Additional thrust without to prepare an engine for a 100-hour inspection? -
increasing fuel flow -Remove cowling and clean
What are the functions of axial flow turbine How may an engine be visually identified? -
nozzles? - -They prepare the mass airflow -By the engine data plate
for driving the turbine rotor and deflect the gases
to a specific angle
What may be used as a guide for 100-hour
inspections on aircraft engines? - -14 CFR
What are some ways of relieving thermal stress part 43 appendix D
on a turbine disk? - -By directing bleed air
on to the face of the disk, or by the grooving in
the turbine disk What additional inspection must be performed if a
cylinder compression is weak? - -An
internal cylinder inspection
What type of compressor blade damage may be
found when inspecting compressor blades? -
-dents, galling, pitting, cracks, scratches, Name at least one place where engine operating
burrs, burns, and gouges limitations may be found - -Type certificate
data sheet, Engine specification, Engine manual,
Aircraft manufacturers maintenance manual
What is used to mark both hot and cold section
parts for repair? - -Layout dye, commercial
felt tip marker, or chalk How does an oil analysis program help to
evaluate the internal condition of an engine? -
-By identifying each wear metal and the
What is the effect of relative humidity on turbojet quantity present in the oil
or turbofan power? - -Negligible
