# Shared Flashcard Set

## Details

Aviation machinist mate
CORE 1 study guide
258
Aviation
Professional
06/10/2013

Term
 Matter
Definition
 Anything that occupies space
Term
 What are the 3 states of matter?
Definition
 Solid, liquid, gas
Term
 Solid
Definition
 Retains shape and volume
Term
 Liquid
Definition
 Retains volume but not shape
Term
 Gas
Definition
 Takes the shape and volume of its container
Term
 Density
Definition
 The amount of quantity of mass per unit
Term
 What are the 4 types of pressure?
Definition
 Static, Impact, Relative, Absolute
Term
 Static pressure
Definition
 Pressure in a confined space or not causing motion
Term
 Impact pressure
Definition
 Pressure caused by motion
Term
 Relative pressure
Definition
 One pressure in relation to anoter
Term
 Absolute pressure
Definition
 Sum of the atmospheric and system pressures starting from a theoretical vaccuum
Term
 Pascals law
Definition
 Pressure applied to an enclosed or confined fluid is transmitted equally in all directions without loss, and acts with equal force on all surfaces
Term
 State the effect of a convergent venturi tube
Definition
 Increased velocity, decreased pressure
Term
 State the effect of divergent venturi tube
Definition
 Decreased velocity, increased pressure
Term
 Whose law deals with volume and temperature?
Definition
 Charles
Term
 Whose law deals with volume and pressure?
Definition
 Boyle
Term
 Newtons Third law
Definition
 For every action there is an equal and opposite reaction
Term
 What atmospheric range provides the best conditions for jet aircraft flight?
Definition
 Stratosphere
Term
 Temperature
Definition
 Intensity of hotness or coldness of a mass in degrees
Term
 List the methods of heat transfer
Definition
Term
 Conduction
Definition
 Molecule to molecule
Term
 Convection
Definition
 Currents in a fluid caused by uneven heating
Term
Definition
 High speed particles of machines
Term
 Define the principles of machines
Definition
 The application of laws, principles and theories that allows us to develop machines to aid us in our daily work
Term
 What are the 2 types of machine principles?
Definition
 Levers and inclined planes
Term
 How does matter change states?
Definition
 Chemical or physical means
Term
 How is matter usually considered?
Definition
 In terms of the energy it contains, absorbs, or gives off
Term
 How may matter be classified?
Definition
 Either an element or a compound
Term
 What particles make up all basic matter?
Definition
 Atom and molecules
Term
 Volume
Definition
 The amount of space an object or substance occupied
Term
 Mass
Definition
 The amount of matter a body contains
Term
 Weight
Definition
 A measurement of force cause by gravity on a unit of mass
Term
 Gravity
Definition
 A force that attracts objects towards the center of the earth
Term
 Force
Definition
 The total pressure acting on an object
Term
 Bernoulli's Principle/ theorem
Definition
 Whenever a stream of fluid has its velocity increased at a given point, the pressure at that point is less than the rest of the stream
Term
 Boyle's law
Definition
 The volume of a given mass of gas varies inversely with pressure when the temperature remains constant
Term
 Charle's law
Definition
 If the volume of a confined gas is constant, the pressure is directly proportional to the absolute temperature. If the pressure is unchanged, the volume is directly proportional to the absolute temperature
Term
 Newton's first law
Definition
 Law of inertia
Term
 Newton's second law
Definition
 F= M x A
Term
 What are the 2 measurements of heat?
Definition
 BTU and Calorie
Term
 BTU
Definition
 British Thermal unit: amount of heat required to raise the temperature of 1 pint of water one degree fahrenheit
Term
 Calorie
Definition
 The amount of heat required to raise the temperature of one gram of water one degree celsius
Term
 What is the chemical breakup of the atmosphere?
Definition
 78% Nitrogen,21% Oxygen,1% Inert Gases
Term
 Atmospheric Pressure
Definition
 A column of air with a one square inch base and a height equal to that of the atmosphere will weigh 14.7 pounds per square inch and support 29.92 inches of mercury on the barometric scale at sea level on a standard day
Term
 Height atmosphere
Definition
 Approximately 200 miles
Term
 Troposphere
Definition
 The lower limit of the atmosphere which contains weather conditions
Term
 Stratosphere
Definition
 Average temperature of -69.7 degrees Fahrenheit and provides the best conditions for jet aircraft flight
Term
 Mesosphere
Definition
 Has conditions that do not allow for gas turbine engine operation due to lack of oxygen
Term
 Thermosphere
Definition
 The electronically charged protection layer for the earth
Term
 How do machines work
Definition
 They either multiply force or speed and lost the other
Term
 What 3 processes must occur for a machine to work?
Definition
 1. input work- work is supplied to the machine.2. Energy is expanded- work is exerted against friction.3. Useful Work- output work is done by the machine.
Term
 How is a machine's efficiency rated?
Definition
 As a number between 0 and 1 which measures the ration of work output dived by work input. The closer to 1, the more efficient the machine.
Term
 How does a machine convert an input force to an output force
Definition
Term
 Lever
Definition
 The most generally used machine principle. Consists of a rigid bar pivoted at a certain point called the fulcrum.
Term
 Inclined Plane
Definition
 A smaller input force can be realized by creating a slope and adding distance to create the same output force.
Term
 Hydraulics
Definition
 The branch of science that deals with the study of liquid in motion.
Term
 Whose law deals with hydraulics?
Definition
 Pascal's
Term
 What is the purpose of hydraulics?
Definition
 To move mechanical components accurately and safely with ease.
Term
 What are the 8 components that make up a basic hydraulic system?
Definition
 1.Reservoir 2. filter 3. pump 4. relief valve 5. selector valve 6. actuating unit 7. Tubing 8. Check valve
Term
 Reservoir
Definition
 Contains fluid supply
Term
 Filter
Definition
 Filters contaminants
Term
 Pump
Definition
 Creates fluid flow
Term
 Relief valve
Definition
 Relieves excess pressure
Term
 Selector valve
Definition
 Directs fluid flow
Term
 Actuating Unit
Definition
 Converts fluid pressure to useful work
Term
 Tubing
Definition
 Transports fluid
Term
 Check valve
Definition
 Permits fluid flow in one direction only
Term
 What is the greatest maintenance hazard with the hydraulic system?
Definition
 Contamination
Term
 What are the classes of contaminants?
Definition
 Abrasives and non- abrasives
Term
 Where do contaminants originate?
Definition
 1. Originally contained in the system2. Introduced from outside sources3. Created within the system during operation4. introduced by foreign liquids
Term
 How do we control contamination?
Definition
 Ensure filters are maintained and ensure minimum contamination
Term
 What are the safety hazards when dealing with a hydraulic system?
Definition
 Extremely high pressures
Term
 Power
Definition
 The rate of doing work or the rate of expending energy
Term
 Motion
Definition
 The act or process of changing place or position
Term
 Velocity
Definition
 The rate of change of distance with respect to time in a given direction
Term
 Acceleration
Definition
 The rate of change of velocity
Term
 Energy
Definition
 The ability to do work or bring about changes in matter
Term
 Jet propulsion
Definition
 Propelling force generated in the direction opposite to the flow of a gas under pressure, which is escaping through an opening called a jet nozzle
Term
 List the conditions of a standard day
Definition
 -Barometric pressure of 29.92" of mercury (14.7 PSI at sea level)-0% Humidity-59F-No wind
Term
 Brayton cycle
Definition
 The thermodynamic cycle of a gas turbine engine to produce thrust. It is a varying volume, constant pressure cycle of events. Commonly called the constant pressure cycle or the combustion cycle
Term
 Thrust
Definition
 The driving force produced by a gas turbine engine
Term
 How is thrust classified?
Definition
 Static or Net
Term
 What power plant variable has the most effect on thrust?
Definition
 Compressor RPM
Term
 What effect will a decrease in temperature have on thrust?
Definition
 Increased thrust
Term
 What type of engine uses only the thrust developed within the engine to produce its force?
Definition
 Turbojet
Term
 Which engine uses extra stages of turbine wheels to drive reduction gearing to drive a rotating airfoil?
Definition
 Turboshaft
Term
 Under the engine designation system, which system is the old system used by the Navy and Air Force?
Definition
 The 2-digit system
Term
 What type of engine is represented by an "x" in the 2-digit system?
Definition
 Experimental
Term
 Described the manufacturer symbols used in part 2 of the 2-digit system
Definition
 Identifies the engine manufacturer using 1 or 2 letter designations
Term
 In the 3 digit system, what does a "J" in part 1 identify?
Definition
 Turbojet
Term
 In the 3 digit system, what does an "F" in part 1 identify?
Definition
 Turbofan
Term
 In the 3 digit system, what does a "T" in part 1 identify?
Definition
 Turboshaft or turboprop
Term
 In the 3 digit system, what does a 100-399 in part 1 identify?
Definition
 Air Force
Term
 In the 3 digit system, what does a 400-699 in part 1 identify?
Definition
 Navy
Term
 In the 3 digit system, what does a 700-999 in part 1 identify?
Definition
 Army
Term
 Where is the data plate located?
Definition
 The forward external portion of the engine
Term
 What information does the data plate contain?
Definition
 -Engine serial number-Engine model designation-Manufacturer code
Term
 What speed does a ramjet engine require to sustain operation?
Definition
 250 MPH
Term
 Who developed the "Aelipile" and when?
Definition
 Hero of Alexandria, 150 B.C.
Term
 Who developed the turbine-powered stamp mill, and when?
Definition
 Giovanni Branca, 1629
Term
 Who produced the first steam jet horseless carriage and when?
Definition
 Ferdinand Veriest, 1678
Term
 When was the earliest use of solid-fuel rockets as weapons?
Definition
Term
 What type of engine was used as a German robot bomb, or V-1 weapon, in 1941?
Definition
 Pulsejet
Term
 When was the first gas turbine engine built?
Definition
 1902 at Cornell University
Term
 What was the first application of a turbojet engine?
Definition
 To drive a supercharger for reciprocating engines ( General electric in 1918)
Term
 When was the first jet propelled flight?
Definition
 27 August 1939
Term
 When was the test flight of the Whittle (W1) turbojet?
Definition
 14 May 1941
Term
 Constant Velocity
Definition
 The distance travelled per unit of time
Term
 What are the 4 continuous and constant events in the Brayton Cycle?
Definition
 Intake, Compression, Combustion, Exhaust
Term
 Which of Newtons laws of motion are applied to obtain thrust?
Definition
 2nd and 3rd
Term
 What are newtons laws called?
Definition
 Laws of force and motion
Term
 What is the name for newtons 1st law?
Definition
 Laws of inertia
Term
 What is the name of for Newtons 2nd law?
Definition
 Law of force and acceleration
Term
 What is the name of Newtons 3rd law?
Definition
 Law of interation
Term
 What is static thrust?
Definition
 The thrust produced when the aircraft or engine has no forward motion
Term
 How are engines rated by their manufacturers?
Definition
 In static thrust under standard day conditions
Term
 Net thrust
Definition
 The thrust available to power the aircraft in flight
Term
 How is power plant RPM expressed?
Definition
 In percent of engine's maximum possible compressor speed/RPM
Term
 How will an increase in RPM affect thrust?
Definition
 Increases thrust
Term
 How will a decrease in RPM affect thrust?
Definition
 Decreases thrust
Term
 How will an increase in outside air temperature affect thrust?
Definition
 Decreases thrust
Term
 How will a decrease in outside air temperature affect thrust?
Definition
 Increases thrust
Term
 OAT
Definition
 Outside Air Temperature
Term
 How will an increase in barometric pressure affect thrust?
Definition
 Increases thrust
Term
 How will a decrease in barometric pressure affect thrust?
Definition
 Decreases thrust
Term
 Humidity
Definition
 The amount of water vapor present in the air at any given time
Term
 Relative Humidity
Definition
 The amount of moisture in the air relative to the maximum amount that the air could contain at the same temperature expressed as a percent
Term
 How will an increase in humidity affect thrust?
Definition
 Decreases thrust
Term
 How will a decrease in humidity affect thrust?
Definition
 Increases thrust
Term
 What does a Y prefix represent?
Definition
 Restricted service
Term
 When is the prefix dropped from the engine designation?
Definition
 When testing is complete
Term
 What branches used the 2-digit system?
Definition
 Navy and Air Force
Term
 In the 2-digit system, what are the 3 possible type symbols?
Definition
 -J-Turbojet-TF-Turbofan-T-Turboshaft/ Turboprop
Term
 In the 2-digit system, how can you tell which service the engine was designed for?
Definition
 In part 1, even numbers starting from 30 represent Navy. Odd numbers from 31 represent Air Force
Term
 In the 2-digit system, what does part two contain?
Definition
 The engine manufacturer symbol, wither 1 or 2 letters
Term
 In the 2-digit system, when is a suffix used?
Definition
 When a minor modifications are incorpoated
Term
 In the 3-digit system, how does the type designator for turbofan engine differ?
Definition
 Instead of TF, F is used to identify turbofan
Term
 In the 3-digit system, what does a 100-399 represent?
Definition
 Air Force
Term
 In the 3-digit system, what does a 400-699 represent?
Definition
 Navy
Term
 In the 3-digit system, what does a 700-999 represent?
Definition
 Army
Term
 Where is the front frame mounted?
Definition
 On the front of the compressor section
Term
 What is the purpose of the front frame section?
Definition
 To receive air from the aircraft air inlet duct and pre-swirl it in the direction of compressor rotation to prevent shock
Term
 What are the purposes of the compressor section?
Definition
 *Supplies compressed air in sufficient quantities to satisfy the requirements of the combustion section*Supply bleed air
Term
 The axial-flow compressor consists of what?
Definition
 Rotating airfoils (rotor blades) and stationary airfoils ( stator vanes)
Term
 Where is the diffuser located?
Definition
 It forms the compressor section rear frame
Term
 How are compressor blades attached to the compressor?
Definition
 By dovetail, fir-tree root, or bulb
Term
 What develops the highest point of pressure in the compressor section?
Definition
 The diffuser
Term
 What component is housed in the front frame section?
Definition
 Inlet Guide Vanes (IGV's)
Term
 What purpose do inlet guide vanes perform?
Definition
 They are hollow to allow for hot air from the engine to circulate through the vanes to prevent ice from forming. They also accommodate tubes to carry oil to and from the front main bearing
Term
 What are the 6 sections of the gas turbine engine?
Definition
 *Front Fame section*Compressor section*Combustion section*Turbine Section*Exhaust Section*Accessory Section
Term
 Where is the compressor section located?
Definition
 Between the front frame section and the combustion section
Term
 What are the 5 main components of the compressor
Definition
 *Casing *Rotor Assembly*Stator Assembly *Guide Vane Assembly *Diffuser
Term
 What components make up 1 stage of compression?
Definition
 Rotor assembly and stator assembly
Term
 What is the defining characteristic of an axial-flow compressor?
Definition
 It compresses the air in a direction that is parallel to the axis of the engine
Term
 What type of compressor casing is most common?
Definition
 Drum type, split horizontally for ease of maintenance
Term
 What component is housed by the compressor casing?
Definition
 Stator assemblies
Term
 What are the 3 components of a rotor assembly?
Definition
Term
 How can rotor blades be locked?
Definition
 Peening, pins, locking wire and keys
Term
Definition
 Stainless steel, aluminum or titanium
Term
 What is the function of the compressor rotor blades?
Definition
 Accelerate air rearward
Term
 Describe stator asseblies
Definition
 Rows of stationary vanes dove-tailed into split-rings and mounted to the compressor casing
Term
 What is the function of the stator vanes?
Definition
 Control air direction for better efficiency
Term
 Where are the exit guide vanes located?
Definition
 The compressor exit
Term
 What is the purpose of exit guide vanes?
Definition
 To straighten compressor discharge air to eliminate turbulence
Term
 What is the function of the diffuser?
Definition
 Develops a pressure wall to prevent reverse flow of combustion gases back into the compressor
Term
 What are the 2 types of axial-flow compressors?
Definition
 Single rotor (solid-spool) dual rotor (split-spool)
Term
 Which stage of the turbine drives the N-1 compressor?
Definition
 The last stage or stages
Term
 Which stage of the turbine drives N-2 compressor?
Definition
 The first stage
Term
 What are the 3 advantages of the axial-flow compressor
Definition
 *High peak efficiencies*Small frontal area*Increased pressure rise by more stages with minimum pressure loss between stages
Term
 What are the 3 disadvantages of an axial-flow compressor?
Definition
 *Heavy weight*Difficult to manufacture- high cost*High starting power requirements
Term
 Where is the combustion section located?
Definition
 Between the compressor and turbine sections
Term
 What is the purpose of the combustion section?
Definition
 To burn the fuel/air mixture, adding heat energy to the mass airflow from the compressor to drive the turbine, which drives the compressor and accessories
Term
 What functions does the combustion section perform?
Definition
 *mix the fuel and air to the proper ratio*Burn the fuel/air mixture*position the flame within the chamber liner*Cool the gases to a temperature that the turbine can withstand*deliver the gases rearward to the turbine section
Term
 What are the 5 components of the combustion section?
Definition
 *Casing (housing)*Chambers*Ignitor plugs*Fuel Nozzles*Fuel drain
Term
 What is the purpose of the ignitor plugs?
Definition
 Provide an air gap for the high-energy spark to ignite the fuel/air mixture
Term
 What are the 2 types of fuel nozzles?
Definition
 Simplex and Duplex
Term
 Describe the duplex fuel nozzle
Definition
 It is widely used due to its good spray characteristics under all operating conditions
Term
 Describe the simplex fuel nozzle
Definition
 It has a spray pattern which is limited in use
Term
 Fuel drain
Definition
 It is located on the bottom of the combustion casing. It provides a means of draining residual fuel during engine shutdown or abnormal starts
Term
 What are the 2 types of combustion chambers?
Definition
 Annular and Can-Annular
Term
 Annular combustion chamber
Definition
 Uses limited space to permit better mixing of the fuel and air for more efficient combustion
Term
 Can-Annular combustion chamber
Definition
 Individual chambers are placed side-by-side to form a circle of cans inside a single casing
Term
 Where is the turbine section located?
Definition
 Between the combustion section and the exhaust section
Term
 What is the purpose of the turbine section?
Definition
 To extract energy from the expanding gases from the combustion section and convert the gases to shaft horse power to drive the compressor and engine-drivenaccessories
Term
 What determines the amount of energy the turbine extracts?
Definition
 *Compressor size*Number of engine-driven accessories *Reduction gearboxes to drive propellers*Rotary airfoils driven by shafts
Term
 What are the components of the turbine section?
Definition
 *Casing(housing)*Nozzle assemblies*Turbine rotor assemblies
Term
 Turbine housing
Definition
 Houses the turbine rotor assembly and provides mounting and support for the turbine nozzle assemblies
Term
 Where are nozzle assemblies located?
Definition
 Directly aft of the combustion chamber assembly and in front of each preceding stage of turbine rotor blades
Term
 What is the function of nozzle assemblies?
Definition
 *to convert heat and pressure energy into velocity energy*Direct gases to the turbine rotor blades at the most efficient angle
Term
 What is the purpose of the turbine rotor assembly?
Definition
 To convert velocity energy from the turbine nozzle into mechanical energy (shaft ) to drive the compressor and engine-driven accessories
Term
 What are the components of the turbine rotor assembly?
Definition
Term
 What is the purpose of the turbine blades?
Definition
 Extract energy from the expanding gases and transmit it to the rotor disk
Term
 What are the 3 types of rotor blades?
Definition
 *impulse*Reaction*Impulse-reaction
Term
 When are the impulse turbine blades used?
Definition
 Low-thrust engines
Term
 When are reaction type turbine blades used?
Definition
 Medium-thrust engines
Term
 When are impulse-reaction type turbine blades used?
Definition
 High-thrust engines
Term
 What is the purpose of the rotor disk?
Definition
 Provide mounting for the rotor blades and transmit power from the blades to the turbine rotor shaft
Term
 What is the purpose of the turbine rotor shaft?
Definition
 To transmit shaft horsepower from the rotor disks to the compressr
Term
 Where is the exhaust section located?
Definition
 Aft of the turbine section
Term
 What are the purposes of the exhaust section?
Definition
 *straighten and direct the gases rearward*Convert the gases into a solid jet stream*Impart a final boost in velocity
Term
 What are the components of the exhaust section?
Definition
 *exhaust duct*Inner cone*Struts*Tailpipe*exhaust nozzle*thermocouples*insulation blankets
Term
 Where is the exhaust duct located?
Definition
 Bolted to the turbine case rear flange
Term
 What are the purposes of the exhaust DUCT?
Definition
 *Collect the exhaust gases and deliver them to the exhaust nozzle*Provide mounting for the thermocouple assemblies*provide mounting for the struts which support the inner cone
Term
 How is the inner cone held in place?
Definition
 With struts or a combination of struts and supporting rods
Term
 What is the purpose of the inner cone?
Definition
 To prevent turbulence
Term
 Why is the design of the inner cone important?
Definition
 It allows the gases to gradually come together to form a solid jet stream
Term
 Why would the inner cone have small holes in it?
Definition
 To allow for reverse flow to cool the last stage of the turbine
Term
 Where are the struts located?
Definition
 Between the housing and the inner cone
Term
 What are the purposes of the struts?
Definition
 *Position and support the inner cone *straighten the swirling gases leaving the turbine *Provide airfoils around the supporting rods to prevent damage
Term
 Where is the tailpipe located?
Definition
 Bolted to the rear flange of the exhaust duct
Term
 What is the purpose of the tailpipe
Definition
 To carry exhaust gases away from the airframe
Term
 Where is the exhaust nozzle located?
Definition
 Attached to the rear flange of the exhaust duct housing, tail pipe, or afterburner duct depending on the aircraft designation
Term
 What is the purpose of the exhaust nozzle?
Definition
 To impart a final boost in velocity to gases leaving the engine
Term
 What are the 2 types of exhaust nozzles?
Definition
 Fixed area and variable area
Term
 Describe a fixed area exhaust nozzle
Definition
 A convergent designed duct with no moving parts which is used on engines producing sub-sonic velocities
Term
 Describe a variable area exhaust nozzle
Definition
 A convergent/ divergent designed duct which opens and closes automatically according to fuel flow and throttle position which allows for increased exhaust nozzle area during afterburner operation
Term
 Where are thermocouples located?
Definition
 Forward, aft, and between stages of turbine. Location is determined by the manufacturer
Term
 How do thermocouples work
Definition
 The produce an electrical signal in proportion to exhaust gas temperatures
Term
 What is the purpose of thermocouples
Definition
 To monitor engine operating conditions through the use of the temperature indicating system
Term
 Where are insulation blankets found?
Definition
 Between the engine and the airframe
Term
 Why are insulation blankets used?
Definition
 To protect the airframe from heat damage
Term
 Where is the accessory section located?
Definition
 Normally mounted at the front of the compressor rotor or on the lower part of the compressor housing
Term
 What are the 2 main gearbox types?
Definition
 *Power take- off gear box at the center front of the compressor hub*Accessory gear box located near the bottom of the compressor
Term
 What are the purposes of the accessory section?
Definition
 To change the compressor rotor speeds to suitable drive speeds for engine accessories*To provide passages and tubing for lubrication of the accessory drive train *To provide mounting pads for engine-driven accessories
Term
 What happens to airflow as it passes through the compressor section?
Definition
 *pressure increases*temperature increases*Velocity stabilizes
Term
 What happens to airflow as it passes through the combustion section?
Definition
 *Pressure decreases*Temperature increases*Velocity Increases
Term
 What happens to airflow as it passes through the turbine section?
Definition
 *Pressure decreases*temperature decreases*velocity increases
Term
 What happens to airflow as it passes through the exhaust section?
Definition
 *pressure decreases*temperature decreases*velocity increases
Term
 Describe APU
Definition
 A small, gas turbine engine located within the airframe of the aircraft
Term
 What are the 4 types of power provided by an APU?
Definition
 *Hydraulic*Electrical*Mechanical*Pneumatic
Term
 What is the bleed air (pneumatic power) from an APU used for?
Definition
 *main engine starting, available from the start bypass valve*aircraft air conditioning, available at the pneumatic power source outlet
Term
 Where is the APU pneumatic power tapped for main engine starting?
Definition
 Start bypass valve
Term
 WHere is the APU pneumatic power tapped for aircraft air conditioning?
Definition
 Pneumatic power source outlet
Term
 What is APU hydraulic and electrical power used for?
Definition
 During ground maintenance allowing the aircraft to be independent of support equipment*For emergency power while in flight
Term
 How can APU hydraulic and electrical power be used in emergency situations?
Definition
 Independently or simultaneously
Term
 How is mechanical power available from an APU?
Definition
 As shaft power at the main output drive pad
Term
 What are the 2 major assemblies of the APU?
Definition
 *Power section assembly*Gearbox assembly
Term
 What are the main components of the APU power section assembly?
Definition
 Compressor, combustion, and turbine
Term
 Describe the APU power section assembly compressor section
Definition
 It is a centrifugal compressor which supplies air for combustion and bleed air requirements
Term
 Describe the APU power section assembly turbine section
Definition
 Single-stage turbine of the radial inflow design
Term
 How are the APU power section assembly compressor and turbine section joined?
Definition
 On a common shaft to make a single balanced rotating assembly and supported by two main bearings
Term
 Describe the APU power section assembly combustion section
Definition
 Chamber of the annular type provides mounting pads for the six fuel nozzles, one ignitor plug and combustion drain valve
Term
 What is the purposes of the APU gearbox assembly?
Definition
 *house the reduction gear train*Provide mounting pads for all or some accessories
Term
 What accessories can be mounted on the APU gearbox assembly?
Definition
 *Fuel pump and accelerator*oil pump assembly*hydraulic starter*speed sensor
Term
 What are the 6 APU systems?
Definition
 *starting system*fuel system*lubrication system*ignition system*electronic sequencing unit (ESU)*Safety control system
Term
 How is starting accomplished by an APU starting system?
Definition
 Hydraulically using an aircraft-mounted hydraulic accumulator
Term
 What component provides hydraulic pressure required by the APU hydraulic starter?
Definition
 Nitrogen-charged accumulator
Term
 What causes the hydraulic charge to release? (APU starting system)
Definition
 Actuation of the APU control switch in the cockpit/flight station
Term
 Describe the APU fuel system receive its fuel supply from?
Definition
 The aircraft fuel system
Term
 Describe the APU lubrication system
Definition
 Provides both pressurized and splash lubrication for all gears, shafts and bearings within the engine
Term
 Describe the APU ignition system?
Definition
 Capacitor discharge type that consists of an ignition exciter, ignitor lead, and ignitor plug
Term
 What are the 3 parts of the APU ignition system?
Definition
Term
 What is the purpose of the Electronic Sequence Unit?
Definition
 Provides the APU with programmed events such as starting, operational checks and overspeed protection
Term
 Describe the APU safety control system
Definition
 Provides automatic starting of the APU as well as safety features to shut down the unit automatically or manually
Term
 What conditions cause the APU safety control system to automatically shut down the system?
Definition
 Oil pressure falls below minimum or turbine Exceeds maximum RPM
Term
 What happens if there is a fire in the APU?
Definition
 An APU Fire warning light will illuminate in the cockpit/flight station. Pulling the T-Handle of the APU control switch will arm the fire extinguisher and remove 28V DC from the control switch
Term
 What are the 3 steps to APU operation?
Definition
 *Power is developed through compression of ambient air by a centrifugal compressor*Compressed air is mixed with fuel that is ignited to drive the turbine*The rotating shaft power of the turbine wheel drives the compressor, accessories, and main output drive pad
Term
 What is acceptable O-Level maintenance on an APU?
Definition
 *Periodic inspection *removal/replacement of components*removal/replacement of the entire APU
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