NAVY AVIATION MACHINIST CORE EXAM SET
2026/2027 QUESTIONS AND SOLUTIONS RATED A+
✔✔Lubrication Heat Exchanger's Purpose - ✔✔Reduce temperature of oil by
transmitting heat from the oil to another fluid (fuel or air)
✔✔Types of Heat Exchangers - ✔✔Air and Fuel
✔✔Lubrication Jets (Nozzles) - ✔✔Directs oil onto bearings and / or gears
May direct air / oil mist or solid spray
✔✔Lubricants - ✔✔Oils and Greases
✔✔Oils - ✔✔Primarily as a lubricant and must be free-flowing and provide cooling,
cleaning, and prevent corrosion
✔✔Viscosity - ✔✔Internal resistance of a liquid that tends to prevent it from flowing
✔✔Types of Lubricating Oils - ✔✔Petroleum and Synthetic
✔✔Petroleum - ✔✔Used in reciprocating (piston) engines and is graded to identify the
series and viscosity of the oil
✔✔Synthetic - ✔✔Capable of withstanding the higher operating temperatures and high
bearing speeds of the gas turbine engine
✔✔MILSPEC # - ✔✔MIL-PRF-23699
✔✔NATO # - ✔✔NATO O-156
✔✔Greases - ✔✔Stable and free from bleeding, non corrosive, and weather and water
resistant
✔✔Types of Greases - ✔✔General Purpose Grease, Extreme High Temperatures
Grease, and Molybdenum Disulfide
✔✔General Purpose Grease - ✔✔For wheel bearings, and where compatibility with
rubber is required
✔✔Extreme High Temperature Grease - ✔✔For high-speed applications such as a ball
or roller bearings
✔✔Molybdenum Disulfide - ✔✔For sliding steel surfaces
, ✔✔Servicing the Lubrication System - ✔✔(1) Engine oil shall be check and serviced
within a specified amount of time after shutdown in accordance with appropriate
technical manual
(2) Aircraft must be on level ground to ensure the oil is not affected by aircraft attitude
(3) Service the Engine Lubrication System in accordance with appropriate technical
manual
(4) The PON-6 pre oiler provides pressurized, filtered oil for servicing. It is a self-
contained hand-operated12 quart system
✔✔Handling Procedures - ✔✔Follow the correct procedures and use the appropriate
personal protective equipment (PPE) to prevent injury
✔✔Disposal Procedures Factors - ✔✔Type and Location
✔✔Main Engine Bearings - ✔✔(1) Support the compressor and turbine rotors and allow
them to rotate freely
(2) Normally between 3 and 7 main bearings are required
✔✔Determines the number of bearings - ✔✔Length, Weight, and Number of Rotors
✔✔Accessory Bearing - ✔✔(1) Absorb loads created by drive shafts and gears
(2) Allows accessory shafts and gears to rotate freely
✔✔Accessory Bearing Location - ✔✔Accessories and Gearboxes
✔✔Types of bearings - ✔✔Ball and Roller
✔✔Ball Bearings - ✔✔Used on compressor and turbine shafts. Absorb both radial and
axial loads
✔✔Roller Bearings - ✔✔Used on high centrifugal force and aborb only radial loads
✔✔Bearing Components - ✔✔Inner and Outer Race, Cage, and Bearing
✔✔Oil Seals Purpose - ✔✔Prevent oil from escaping its normal path of flow
✔✔Types of Oil Seals - ✔✔Labyrinth, Thread, and Carbon
2026/2027 QUESTIONS AND SOLUTIONS RATED A+
✔✔Lubrication Heat Exchanger's Purpose - ✔✔Reduce temperature of oil by
transmitting heat from the oil to another fluid (fuel or air)
✔✔Types of Heat Exchangers - ✔✔Air and Fuel
✔✔Lubrication Jets (Nozzles) - ✔✔Directs oil onto bearings and / or gears
May direct air / oil mist or solid spray
✔✔Lubricants - ✔✔Oils and Greases
✔✔Oils - ✔✔Primarily as a lubricant and must be free-flowing and provide cooling,
cleaning, and prevent corrosion
✔✔Viscosity - ✔✔Internal resistance of a liquid that tends to prevent it from flowing
✔✔Types of Lubricating Oils - ✔✔Petroleum and Synthetic
✔✔Petroleum - ✔✔Used in reciprocating (piston) engines and is graded to identify the
series and viscosity of the oil
✔✔Synthetic - ✔✔Capable of withstanding the higher operating temperatures and high
bearing speeds of the gas turbine engine
✔✔MILSPEC # - ✔✔MIL-PRF-23699
✔✔NATO # - ✔✔NATO O-156
✔✔Greases - ✔✔Stable and free from bleeding, non corrosive, and weather and water
resistant
✔✔Types of Greases - ✔✔General Purpose Grease, Extreme High Temperatures
Grease, and Molybdenum Disulfide
✔✔General Purpose Grease - ✔✔For wheel bearings, and where compatibility with
rubber is required
✔✔Extreme High Temperature Grease - ✔✔For high-speed applications such as a ball
or roller bearings
✔✔Molybdenum Disulfide - ✔✔For sliding steel surfaces
, ✔✔Servicing the Lubrication System - ✔✔(1) Engine oil shall be check and serviced
within a specified amount of time after shutdown in accordance with appropriate
technical manual
(2) Aircraft must be on level ground to ensure the oil is not affected by aircraft attitude
(3) Service the Engine Lubrication System in accordance with appropriate technical
manual
(4) The PON-6 pre oiler provides pressurized, filtered oil for servicing. It is a self-
contained hand-operated12 quart system
✔✔Handling Procedures - ✔✔Follow the correct procedures and use the appropriate
personal protective equipment (PPE) to prevent injury
✔✔Disposal Procedures Factors - ✔✔Type and Location
✔✔Main Engine Bearings - ✔✔(1) Support the compressor and turbine rotors and allow
them to rotate freely
(2) Normally between 3 and 7 main bearings are required
✔✔Determines the number of bearings - ✔✔Length, Weight, and Number of Rotors
✔✔Accessory Bearing - ✔✔(1) Absorb loads created by drive shafts and gears
(2) Allows accessory shafts and gears to rotate freely
✔✔Accessory Bearing Location - ✔✔Accessories and Gearboxes
✔✔Types of bearings - ✔✔Ball and Roller
✔✔Ball Bearings - ✔✔Used on compressor and turbine shafts. Absorb both radial and
axial loads
✔✔Roller Bearings - ✔✔Used on high centrifugal force and aborb only radial loads
✔✔Bearing Components - ✔✔Inner and Outer Race, Cage, and Bearing
✔✔Oil Seals Purpose - ✔✔Prevent oil from escaping its normal path of flow
✔✔Types of Oil Seals - ✔✔Labyrinth, Thread, and Carbon
