AT103 Review Through Exam 2 Flashcards
The purpose of a lubrication system is to supply oil to the engine at the correct… (3)
Pressure
Volume
Location
must hold the adequate amount of oil
Oil tank
must maintain the temperatures are the proper level
Cooling devices
Principle Components of a Lubrication System (9)
Pressure Oil Pump
Oil Pressure Relief Valve
Oil Reservoir
Oil Pressure Gage
Oil Temperature Gage
Oil Filter
Necessary Piping and Connections
Oil Coolers
Oil Dilution Systems if operating in cold conditions
Oil Capacity
must be sufficient to supply the engine
Fuel-Oil ratio should be around 30:1 by volume
Plumbing for Lubrication System
Constructed of aluminum alloy tubing and connections
Temperature Regulation
Designed to maintain the temperature of the oil at the correct level
Oil Pressure Relief Valve
Control and limit the lubricating oil pressure
Prevent damage to the lubrication system
Ensure lubrication in case of a system failure
Several types of oil pressure relief valves
Engine Oil Filter Types (5)
Full-Flow
Bypass
Strainer
Spin-On
Cuno Oil
Full-Flow Type
Filtering all the circulated oil of contaminants
All oil are filtered before passing through bearing surfaces
Bypass Type
Filters about 10% of the oil through filtering element and returns oil to sump
Oil passing through bearings are not filtered oil
Strainer-Type Filter
Designed to collapse when clogged or designed with relief valves that also open when clogged
Spin-On Type Filter
Canister and filter element are one unit
Cuno Oil Filter
Contaminants are trapped on the outer diameter of the plates
Disposable Filter Cartridge
The filter canister is reused while the filter element is replaced
Engine Oil Analysis
Determine the origin of the foreign particles discovered
Oil Pressure Gage
Measures from no pressure up to above the maximum pressure
Oil Temperature Gage
Sensors are usually at the oil inlet line or on the oil filter housing
Oil Pressure Pump Types (2)
Gear Type
Vane Type
Oil Pressure Pumps
Capacity of oil pressure pump is greater than the engine requires
Excess oil is returned by a relief valve to the oil inlet
Accommodates engine wear and growing clearances
Scavenge Pumps
Usually used for a dry-sump lubrication system
Greater capacity than the pressure pumps
Oil that flows to the sump are often foamy
A larger capacity is required to keep the oil sump drained
Induction System Sections (3)
Air scoop and ducting to the carburetor
The carburetor or air control section of injection system
The intake manifold and pipes
Four principal parts of the Air Scoop and Ducting
Air scoop
Air filter
Alternate air valve
Carburetor air heater
Air Scoop
Opening facing into the airstream
Receives ram air
Air Filters
Installed at or near the air scoop
Blocks dirt, abrasive particles, sand, and larger foreign materials
Reduces air pressure to the carburetor
Three Air Filter Types
Wetted
Dry Paper
Polyurethane Foam
Wetted Type Mesh Filters
Mat or metal filaments encased in a frame and dipped into oil
Oil film catches and holds dust and sand particles
Dry Paper Filters
Air passes pleated layer of paper elements
Replaced on a time-in-service basis
Polyurethane Foam Filters
Polyurethane foam and a wetting agent
Newer type of air filter
Alternative Air Valve
Allows air to flow to the engine if air filter is clogged
Valve can be manually controlled from the cockpit or automatic
Carburetor Heat Valve
Operated by the carburetor heat control in the cockpit
The valve closes the main air duct and opens the duct to the heater muff
Intake Manifolds
Individual pipe leading to each cylinder
One end of the pipe is bolted to the cylinder
Induction System Icing
May cut off air fuel charge or vary air fuel ratio
Ice forms in induction system while flying through (6)
Clouds
Fog
Rain
Sleet
Snow
High moisture clear air
Types of icing (3)
Impact Ice
Fuel Evaporation Ice
Throttle Ice
Induction icing can be detected by
reduction in engine power while maintaining the same throttle position
Aircraft operating in icing conditions should be equipped with a
carburetor air temperature (CAT) gage
Carburetor Air Temperature (CAT)
Reads temperature of the air as it enters the carburetor
If CAT is below __°F and experiencing engine loss of power, it is assumed that icing exists
32
Exhaust Systems
Removes the products of combustion from the engine safely and effectively
Poor maintenance of exhaust systems may lead to (4)
Nacelle fire
Toxic gases entering the cockpit and cabin
Damage to parts and structure in nacelle
Poor engine performance
Development of Exhaust Systems
Early aircraft engines have very simple exhaust systems
Short steel stacks are attached to the exhaust ports
These systems were noisy and permitted exhaust gases to flow into the open cockpits of the aircraft
Heat collected from the exhaust are employed for (3)
Cabin Heating
Carburetor Anti-Icing
Windshield Defrosting
Modern aircraft exhaust systems includes (5)
Exhaust Manifolds
Heat Exchangers
Mufflers
Turbochargers
Augmenters
Principles of Carburetion (4)
Provide combustible mixture of air and fuel necessary for the engine to operate
Deliver an accurately metered air fuel mixture
Provide for automatic or manual mixture correction under changing conditions
Have a sturdy construction to provide durability and resistance to the effects of vibration
Carburetors play an extremely important part in (3)
Engine performance
Engine mechanical life
General efficiency of the aircraft
Gasoline and other liquid fuels will not…
burn in the liquid state
Gasoline and other liquid fuels must be…
vaporized and combined with the correct amounts of oxygen to form a combustible mixture
When just enough oxygen is present the fuel…
will burn completely
When there is not quite enough oxygen, combustion…
will occur but will not be complete
When there is too much oxygen, the mixture…
will not burn
Essential Parts of Float Type Carburetors (7)
Float Mechanism and its Chamber
Strainer
Main Metering System
Idling System
Economizer System
Accelerating System
Mixture Control System
Float Mechanism
Designed to control the level of fuel in the float chamber
Fuel Strainer
a fine wire mesh that will intercept any dirt particles
Main Metering System
Controls the fuel feed in the upper half of the engine speed range
Units of the Main Metering System (3)
Main Metering Jet
Main Discharge Nozzle
Passage Leading to the Idling System
Three functions of the main metering system
Proportion the A/F mixture
Decrease the pressure at the discharge nozzle
Control the airflow at full throttle
Idling System
Delivers fuel only when throttle valve is nearly closed
Accelerating System
When throttle of the engine is suddenly opened
Economizer System
A valve that is closed at low engine and cruising speeds
Functions of the Mixture Control System (2)
Prevent mixture from becoming too rich at high altitudes
Economize on fuel during engine operation in the low power range
Idle Cutoff
Stops the flow of fuel from the discharge nozzle
Stops the engine
Disadvantages of Float Type Carburetors (2)
The fuel flow disturbances in aircraft maneuvers may interfere with the functions of the float mechanism
During icing conditions, the discharge of fuel into the airstream ahead of the throttle causes a drop of temperature and results in ice forming at the throttle valve (carb ice)
The introduction of fuel or air fuel mixture into the induction system or combustion chamber of each cylinder by means of a
pressure’s source
Fuel Injection Carburetor
Discharges fuel into the airstream at or near carburetor (throttle body)
Fuel Injection System
Discharges fuel into the intake port of each cylinder (multi-point)
Advantages of Fuel Injection Systems (5)
Freedom from vaporization icing (carb icing)
More uniform delivery of air fuel mixture to each cylinder
Improved control of fuel/air ratio
Instant acceleration after idling with no tendency to stall
Increased engine fuel efficiency and power
Bendix RSA Fuel Injection System
Designed to meter fuel in direct ratio to the volume of air being consumed by the engine
When air velocity _________, pressure of the impact tubes _______ ________
increases, remains constant
The differential pressure is used as a measurement of the…
volume of air consumed
The Servo Pressure Regulator
Fuel flow to the engine, passing through the metering jet generates a fuel pressure differential with unmetered fuel
The two opposite forces (fuel and air differentials) are…
equal
If the throttle is opened, airflow…
increases
The servo valve opening…
decreases the pressure in the meter fuel chamber
More fuel is increased to the engine to…
support the higher power level requested
Idle Valve
Connected to the throttle linkage
Externally adjustable
Manual Mixture Control
A sliding valve
Used by the pilot to effectively reduce the size of the metering jet
By changing the metering jet’s effective size, the pilot has the option of…
manually leaning the mixture
shutting off the fuel flow to the engine at engine shutdown
Flow Dividers
Ensures equal distribution of metered fuel to the nozzles
Provides isolation of each nozzle for clean engine shutdown
At idle, fuel pressure is…
only enough to move the flow divider valve slightly
Nozzles are of ___ _____ type
air bleed
Fuel is discharged inside the nozzle body into a chamber which is vented to…
atmospheric air pressure
Nozzle is mounted in the…
intake valve port of the cylinder head
Spark plug
Electric energy of the high-voltage current produced by the magneto is converted to heat energy
What type of energy is required to ignite the air fuel mixture in the cylinders
Heat energy
An air gap in the spark plug allows the high voltage of the ignition system to…
Produce a spark
Three major parts of a spark plug
The Electrodes
The Ceramic Insulator
The Metal Shell
Types of Spark Plugs (4)
Resistor-Type
Unshielded
Massive Electrode
Fine Wire
Resistor-Type Spark Plugs
Designed to reduce the burning and erosion of electrodes in engines having shielded harness
Unshielded Spark Plugs
used in light aircraft engines
Massive Electrode Type Spark Plugs
Named because of the size of the center and ground electrodes
Electrodes have copper core
Fine Wire Type Spark Plugs
Similar construction to the massive electrode type
Electrodes are made of platinum and iridium
Four Forms of Electrode Construction
Projected Core Nose
Two-Prong Fine-Wire
Two-Prong Ground
Push-Wire
Spark Plug Reach
The linear distance from the shell gasket seat to the end of the shell threads
The reach of the spark plug required for an engine is determined by the…
cylinder-head design
Shell threads are classified as (2)
14- or 18-mm diameter
Long Reach or Short Reach
Classification of Spark Plugs Heat rating range (2)
Numbers 26-50 indicate coldest to hottest heat range
Numbers 76-99 indicate special application aviation plugs
Classification of Spark Plugs Gap and Electrode style (5)
E = Two Prong Aviation
N = Four Prong Aviation
P = Platinum Fine Wire
B = Two Prong Massive
R = Push Wire
Heat Range of Spark Plugs
The ability of the spark plugs to transfer heat from the firing end of the spark plug to the cylinder head
Spark plugs are classified as (3)
Hot
Normal
Cold
If an engine typically runs hot, a relatively ___ spark plug is required
cold
If an engine typically runs cold, a relatively ___ spark plug is required
hot
If a hot spark plug is installed in a hot engine…
spark plug tip will overheat and cause pre-ignition
If a cold spark plug is installed in a cold engine…
spark plug tip will collect unburned carbon and the plugs will be fouled
Servicing Procedure (10)
Removal
Preliminary Inspection
Degreasing
Drying
Cleaning
Re-gapping
Inspection and Testing
Gasket Servicing
Plug Rotation
Installation
How is Magneto Ignition superior to Battery Ignition? (3)
Produces a hotter spark at high engine speeds
Self-contained unit
Not dependent on any eternal source of electric energy
Magnetos Classification (8)
Low Tension
High Tension
Rotating Magnet
Inductor Rotor
Single
Double
Flange Mounted
Base Mounted
Magnetos Classification Groupings (3)
Low Tension vs. High Tension
Single vs. Double
Flange Mounted vs. Base Mounted
Low Tension Magnetos
Delivers current at a low voltage
High Tension Magnetos
Delivers current at a high voltage
Single Magentos
Two single type magnetos are usually used on reciprocating engines
Double Magentos
Essentially two magnetos having one rotating magnet and driveshaft common to both
Flange Mounted Magnetos
Attached to the engine by means of a flange on the end of the magneto
Base Mounted Magnetos
Attached to the engine by means of brackets securing the base
Magnetos require inspection at…
regular intervals
Usually, magnetos should be inspected…
after every 100 hours of operation or during the annual inspection
A in depth inspection is required…
after 500 hours of service
Worn or damaged components should be ___ during the inspection
replaced
Characteristics of gasoline (4)
High heat value
Ability to evaporate when exposed to air
Ability to evaporate at ordinary temperatures
High volatility
What is desirable of gasoline for engine starting?
High volatility
Too high volatility will form bubbles in the fuel lines causing…
vapor locks
Lead oxide remains as a residue in the…
cylinders
Grades produced for civil use (4)
100 (green)
100LL (blue)
UL94 (unleaded)
UL91
Lead exposure can occur through… (3)
Airborne lead emissions impacting neighboring communities
Past emissions deposited to soil and other surfaces
Occupational lead exposures for airport workers (inhalation, ingestion, and dermal absorption)
Aircraft engines are designed to operate with…
specific fuel octane ratings or performance numbers
The minimum octane rating or performance number is ____ ________ than the maximum
more critical
What can a too high or too low octane rating do?
Damage or cause failure of the engine
What does using fuel with too low of a rating?
detonation and damage of pistons and cylinders
Benefits of removing lead (4)
Eliminates lead deposits on spark plugs
Decreases acidity of oil and corrosion
Better protect engine from corrosion, wear, and tear
Advance in aviation technology
Aviation fuel must be free of any impurities such as (7)
Water
Dirt
Microorganisms
Acid
Alkali
Sulfur
Gum Contents
What may gum contents cause? (3)
Valves to stick
Clog fuel metering jets
Cause restrictions within the fuel system
At high altitude, fuel cools well below freezing point, the water in the fuel forms…
ice crystals
Ice crystals
block off the fuel system and shut off the flow of fuel
Fuel System Principal Sections (2)
Aircraft Fuel System
Engine Fuel System
Parts of the Aircraft Fuel System (9)
Fuel Tanks
Fuel Boost Pump
Tank Strainer
Fuel Tank Vents
Fuel Lines
Fuel Control or Selector Valves
Main Strainer
Fuel Flow and Pressure Gages
Fuel Drain Valves
Characteristics of an Engine Fuel System (2)
Begins from Engine Driven Pump
Fuel Control Units in the Carburetor or Fuel Metering Device
Fuel system must be capable of delivering continuous flow of clean fuel under positive pressure from…
fuel tank to the engine
Gravity systems must have tanks placed high enough from the carburetor to provide ___% of required fuel flow pressure (takeoff)
150
Pressure systems must be capable of ___% of the actual takeoff fuel flow of the engine
125
Boost pump must be available for… (4)
starting
takeoff
landing
high altitudes
Fuel Systems must provide valves to
shut off fuel
Multiengine aircraft engines are supplied from its own ____, _____, and ____ ____
tank, lines, fuel pump
What can be done in an emergency?
transfer fuel from tank to tank or running two engines from one tank
Gravity system should…
supply fuel to one engine from one tank
Fuel lines should… (2)
be sufficient to carry maximum required fuel flow under all conditions
have no sharp bends or rapid rises, and kept away from hot parts of the engine as much as possible
Fuel tanks should… (3)
have drains and sumps to remove water and dirt from the bottom of the tank
be able to withstand all loads they may be subjected to during operation
provide baffles if a shift in fuel position will cause a change in aircraft balance
Gravity-Fed Systems
Fuel is delivered to the engine solely by gravity
Pressure Systems
When fuel tanks cannot be placed the required distance above the carburetors or a greater pressure is required for operation
Strainers & Filters
Removes dirt particles from the fuel
