NAVY AVIATION MACHINIST TEST PAPER 2026/2027
QUESTIONS AND SOLUTIONS RATED A+
✔✔Thermocouple Assembly - ✔✔Constructed of two dissimilar metals, Alumel and
Chromel, which, when heated, will create a small voltage that is directly proportional to
the engine exhaust temperature
Ex: Using heat excites the energy from the metals and creates that small voltage that
sends it to the Indicator
✔✔Engine Temperature Indicator - ✔✔Displays temperature in degrees Celsius or
Fahrenheit
✔✔Fuel Flow Indicating System's Components - ✔✔Fuel Flow Transmitter, and Fuel
Flow Indicator
✔✔Fuel Flow Transmitter - ✔✔(1) Mounted on the engine
(2) The transmitter provides an electrical signal that is directly proportional to the mass
rate of fuel flow and transmits the signal to the flight station / cockpit
✔✔Fuel Flow Indicator - ✔✔Displays the signal as fuel flow in pounds-per-hour (PPH)
✔✔Oil Pressure Indicating System's Components - ✔✔Oil Pressure Transmitter and Oil
Pressure Indicator
✔✔Oil Pressure Transmitter - ✔✔(1) Mounted on the engine
(2) Sends a proportional electrical signal to the flight station / cockpit
✔✔Oil Pressure Indicator - ✔✔Displays oil pressure in pounds-per-square-inch (PSI)
✔✔Engine Fire Detection System's Components - ✔✔Fire Detection Element and Fire
Warning Light
✔✔Fire Detection Element - ✔✔Senses an overheat condition or fire and transmits a
signal to the flight station / cockpit
✔✔Fire Warning Light - ✔✔(1) Receives its signal from the fire detection element to
illuminate the flight station / cockpit
(2) When the temperature in the engine cavity reaches an overheat condition, the
sensors will provide a signal, allowing a small current to flow, which is transmitted to
illuminate the fire warning light
, ✔✔Engine Starting System's Purpose - ✔✔Provides initial rotation to accelerate the
engine to the point where ignition can be accomplished and sustained
✔✔Engine Ignition System's Type - ✔✔High Energy Capacitor Discharge: Spark must
be constant under varying conditions
✔✔Engine Ignition System Components - ✔✔Input Leads, Transformer (Exciter), Ignitor
Leads, and Ignitor Plugs
✔✔Input Leads - ✔✔Delivers input power from the aircraft electrical system, or from an
external power source, to the transformer
✔✔Transformer (Exciter) - ✔✔Steps up the input voltage to the rated output voltage.
✔✔Ignitor Leads - ✔✔Delivers power to ignitor plugs
✔✔Ignitor Plugs - ✔✔Provides and air gap for voltage arc
✔✔Auxiliary Power Unit Description - ✔✔A small gas turbine engine located within the
airframe of the aircraft
✔✔Auxiliary Power Unit Purposes - ✔✔Supplies bleed air (pneumatic power) for:
(1) Main engine starting, which is available at the start bypass valve.
(2) Aircraft air conditioning, which is available at the pneumatic power source outlet
The APU also supplies electrical and hydraulic sources of power to operate selected
aircraft systems, which are used:
(1) During ground maintenance allowing the aircraft to be independent of support
equipment
(2) For emergency electrical and hydraulic power while in flight
Additionally, the APU supplies mechanical power, which is available as shaft power at
the main output drive pad
✔✔APU Assemblies - ✔✔Power Section Assembly and Gearbox Assembly
✔✔Power Section Assembly - ✔✔Compressor, Combustion, and Turbine
✔✔Compressor Section - ✔✔(1) Is a centrifugal compressor
(2) Supplies air for combustion and bleed air requirements
QUESTIONS AND SOLUTIONS RATED A+
✔✔Thermocouple Assembly - ✔✔Constructed of two dissimilar metals, Alumel and
Chromel, which, when heated, will create a small voltage that is directly proportional to
the engine exhaust temperature
Ex: Using heat excites the energy from the metals and creates that small voltage that
sends it to the Indicator
✔✔Engine Temperature Indicator - ✔✔Displays temperature in degrees Celsius or
Fahrenheit
✔✔Fuel Flow Indicating System's Components - ✔✔Fuel Flow Transmitter, and Fuel
Flow Indicator
✔✔Fuel Flow Transmitter - ✔✔(1) Mounted on the engine
(2) The transmitter provides an electrical signal that is directly proportional to the mass
rate of fuel flow and transmits the signal to the flight station / cockpit
✔✔Fuel Flow Indicator - ✔✔Displays the signal as fuel flow in pounds-per-hour (PPH)
✔✔Oil Pressure Indicating System's Components - ✔✔Oil Pressure Transmitter and Oil
Pressure Indicator
✔✔Oil Pressure Transmitter - ✔✔(1) Mounted on the engine
(2) Sends a proportional electrical signal to the flight station / cockpit
✔✔Oil Pressure Indicator - ✔✔Displays oil pressure in pounds-per-square-inch (PSI)
✔✔Engine Fire Detection System's Components - ✔✔Fire Detection Element and Fire
Warning Light
✔✔Fire Detection Element - ✔✔Senses an overheat condition or fire and transmits a
signal to the flight station / cockpit
✔✔Fire Warning Light - ✔✔(1) Receives its signal from the fire detection element to
illuminate the flight station / cockpit
(2) When the temperature in the engine cavity reaches an overheat condition, the
sensors will provide a signal, allowing a small current to flow, which is transmitted to
illuminate the fire warning light
, ✔✔Engine Starting System's Purpose - ✔✔Provides initial rotation to accelerate the
engine to the point where ignition can be accomplished and sustained
✔✔Engine Ignition System's Type - ✔✔High Energy Capacitor Discharge: Spark must
be constant under varying conditions
✔✔Engine Ignition System Components - ✔✔Input Leads, Transformer (Exciter), Ignitor
Leads, and Ignitor Plugs
✔✔Input Leads - ✔✔Delivers input power from the aircraft electrical system, or from an
external power source, to the transformer
✔✔Transformer (Exciter) - ✔✔Steps up the input voltage to the rated output voltage.
✔✔Ignitor Leads - ✔✔Delivers power to ignitor plugs
✔✔Ignitor Plugs - ✔✔Provides and air gap for voltage arc
✔✔Auxiliary Power Unit Description - ✔✔A small gas turbine engine located within the
airframe of the aircraft
✔✔Auxiliary Power Unit Purposes - ✔✔Supplies bleed air (pneumatic power) for:
(1) Main engine starting, which is available at the start bypass valve.
(2) Aircraft air conditioning, which is available at the pneumatic power source outlet
The APU also supplies electrical and hydraulic sources of power to operate selected
aircraft systems, which are used:
(1) During ground maintenance allowing the aircraft to be independent of support
equipment
(2) For emergency electrical and hydraulic power while in flight
Additionally, the APU supplies mechanical power, which is available as shaft power at
the main output drive pad
✔✔APU Assemblies - ✔✔Power Section Assembly and Gearbox Assembly
✔✔Power Section Assembly - ✔✔Compressor, Combustion, and Turbine
✔✔Compressor Section - ✔✔(1) Is a centrifugal compressor
(2) Supplies air for combustion and bleed air requirements
