NAVY AVIATION MACHINIST COMPREHENSIVE EXAM
2026/2027 QUESTIONS AND SOLUTIONS RATED A+
✔✔Ignitor plugs - ✔✔Provides an air gas for the high energy spark to ignite fuel/air
mixture
✔✔Fuel Nozzle - ✔✔2 types
Duplex-Most widely used due to good spray characteristics under all operating
conditions
Simplex- Have a spray pattern which is limited in use
✔✔Fuel Drain - ✔✔Located on the bottom of the combustion casing provides a means
of draining residual fuel during engine shut down or after abnormal start
✔✔Turbine Section - ✔✔Located between the combustion section and exhaust section
Purpose to extract energy from the expanding gases from the combustion and
conversion the gases to shaft horsepower to drive the compressor and engine driven
accessories
✔✔Turbine Section Components - ✔✔Casing
Nozzle Assembly
Turbine Rotor Assembly- Rotor Blades
✔✔Nozzle Assembly - ✔✔Located directly aft of the combustion chamber assembly and
in front of each preceding stage of turbine rotor blades. Converts heat and pressure into
velocity energy
✔✔Turbine rotor assembly - ✔✔Purpose to convert velocity energy into mechanical
energy to drive the compressor and engine driven accessories
✔✔Turbine rotor blade types - ✔✔Impulse-Low Thrust
Reaction-Medium Thrust
Impulse Reaction-High Thrust
✔✔Engine Exhaust Section - ✔✔Aft of the turbine section
Purpose to straighten and direct gases rearward convert the gases into a solid jet
stream and impart's a final boost in velocity
✔✔Inner Cone - ✔✔Held in place in the center of the exhaust duct. Used to prevent
turbulence. Allows gases to gradually come together and form a jet stream.
May have small holes for reverse flow to cool turbines
✔✔Struts - ✔✔Located between housing and the inner cone
Purpose to position and hold the inner cone and straighten swirling gases leaving the
turbine.
, ✔✔Exhaust Nozzle - ✔✔Location: Attached to the rear flange of the exhaust duct,
housing, tailpipe, or the afterburner duct.
To impart the final boost in velocity to the gases leaving the exhaust.
2 types Fixed Area and Variable Area
✔✔Turbine Engine Accessory Section - ✔✔Power Take Off (PTO)- Center front of of
the compressor hub
Accessory Gearbox- Normally located near the bottom of the compressor
Purpose to change the rotor speed to suitable speeds and to provide passageways and
tubing for lubricating mechanical drive train (gears)
Mounting pads for accessories
✔✔Thrust Augmentation - ✔✔Purpose to increase the basic turbojet/turbofan engine
thrust to meet takeoff/ flight requirements
✔✔Water injection system - ✔✔Water acts a combustion chamber and turbine coolant,
producing a higher thrust for conventional takeoff and vertical shot take-off and landing
(VSTOL)
Supplies water under pressure to the combustion chamber and turbine engine inlet
where it mixes with the airflow to act as a coolant
This action increase fuel flow and engine revolutions per minutes producing an increase
in thrust without excessive heat.
✔✔Thrust Nozzle Control System - ✔✔The operation of water injection system depends
on the throttle position and thrust nozzle control lever position. The ability to vector
engine thrust requires coordination of the throttle and the nozzle control lever.
Allows water to flow when the throttle position is 96% and 98% RPM.
The nozzles can direct engine thrust up to 98.5 degrees.
✔✔Afterburner - ✔✔Turbojet: 75% of exhaust gases are unburned air. Adding fuel and
igniting the mixture accelerate the exhaust gases rearward. Additional Thrust
Turbofan: Mixing secondary bypass air with primary air increase thrust upon section of
the A/B ignition. Thrust increases approximately 50% while fuel flow triples operation in
the A/B is limited to only a few minutes.
✔✔ Matter - ✔✔Anything that takes up space. Can change from one state to another.
Made up of Elements or Compounds.
✔✔states of matter - ✔✔solid, liquid, gas
✔✔Solid - ✔✔state of matter with a definite shape and volume
✔✔liquid - ✔✔A state of matter that has a definite volume but no definite shape.
2026/2027 QUESTIONS AND SOLUTIONS RATED A+
✔✔Ignitor plugs - ✔✔Provides an air gas for the high energy spark to ignite fuel/air
mixture
✔✔Fuel Nozzle - ✔✔2 types
Duplex-Most widely used due to good spray characteristics under all operating
conditions
Simplex- Have a spray pattern which is limited in use
✔✔Fuel Drain - ✔✔Located on the bottom of the combustion casing provides a means
of draining residual fuel during engine shut down or after abnormal start
✔✔Turbine Section - ✔✔Located between the combustion section and exhaust section
Purpose to extract energy from the expanding gases from the combustion and
conversion the gases to shaft horsepower to drive the compressor and engine driven
accessories
✔✔Turbine Section Components - ✔✔Casing
Nozzle Assembly
Turbine Rotor Assembly- Rotor Blades
✔✔Nozzle Assembly - ✔✔Located directly aft of the combustion chamber assembly and
in front of each preceding stage of turbine rotor blades. Converts heat and pressure into
velocity energy
✔✔Turbine rotor assembly - ✔✔Purpose to convert velocity energy into mechanical
energy to drive the compressor and engine driven accessories
✔✔Turbine rotor blade types - ✔✔Impulse-Low Thrust
Reaction-Medium Thrust
Impulse Reaction-High Thrust
✔✔Engine Exhaust Section - ✔✔Aft of the turbine section
Purpose to straighten and direct gases rearward convert the gases into a solid jet
stream and impart's a final boost in velocity
✔✔Inner Cone - ✔✔Held in place in the center of the exhaust duct. Used to prevent
turbulence. Allows gases to gradually come together and form a jet stream.
May have small holes for reverse flow to cool turbines
✔✔Struts - ✔✔Located between housing and the inner cone
Purpose to position and hold the inner cone and straighten swirling gases leaving the
turbine.
, ✔✔Exhaust Nozzle - ✔✔Location: Attached to the rear flange of the exhaust duct,
housing, tailpipe, or the afterburner duct.
To impart the final boost in velocity to the gases leaving the exhaust.
2 types Fixed Area and Variable Area
✔✔Turbine Engine Accessory Section - ✔✔Power Take Off (PTO)- Center front of of
the compressor hub
Accessory Gearbox- Normally located near the bottom of the compressor
Purpose to change the rotor speed to suitable speeds and to provide passageways and
tubing for lubricating mechanical drive train (gears)
Mounting pads for accessories
✔✔Thrust Augmentation - ✔✔Purpose to increase the basic turbojet/turbofan engine
thrust to meet takeoff/ flight requirements
✔✔Water injection system - ✔✔Water acts a combustion chamber and turbine coolant,
producing a higher thrust for conventional takeoff and vertical shot take-off and landing
(VSTOL)
Supplies water under pressure to the combustion chamber and turbine engine inlet
where it mixes with the airflow to act as a coolant
This action increase fuel flow and engine revolutions per minutes producing an increase
in thrust without excessive heat.
✔✔Thrust Nozzle Control System - ✔✔The operation of water injection system depends
on the throttle position and thrust nozzle control lever position. The ability to vector
engine thrust requires coordination of the throttle and the nozzle control lever.
Allows water to flow when the throttle position is 96% and 98% RPM.
The nozzles can direct engine thrust up to 98.5 degrees.
✔✔Afterburner - ✔✔Turbojet: 75% of exhaust gases are unburned air. Adding fuel and
igniting the mixture accelerate the exhaust gases rearward. Additional Thrust
Turbofan: Mixing secondary bypass air with primary air increase thrust upon section of
the A/B ignition. Thrust increases approximately 50% while fuel flow triples operation in
the A/B is limited to only a few minutes.
✔✔ Matter - ✔✔Anything that takes up space. Can change from one state to another.
Made up of Elements or Compounds.
✔✔states of matter - ✔✔solid, liquid, gas
✔✔Solid - ✔✔state of matter with a definite shape and volume
✔✔liquid - ✔✔A state of matter that has a definite volume but no definite shape.
