Aircraft Systems Flashcards
Oil System Purpose (5)
Lubrication Cooling Cleaning Sealing Actuating
Components of Oil System (6)
When does the gauge begin to indicate for summer and winter?
Pump – circulates oil through system
Sump – reservoir for oil
Filter – removes contaminates from oil
Oil Pressure Gauge
–Should begin to indicate within…
•30 seconds in summer
•60 seconds in winter
•Oil Temperature Gauge
•Oil CoolerInduction System Malfunctions (7)
Does the C172 come equipped with an alternate air?
Loss of Fuel Enrich Mixture Boost Pump Fuel Selector Loss of Air Carburetor Heat Alternate Air •C172 is equipped with an automatic “alternate air”
Methods of Leaning (2)
Best Economy – leaning for Best Economy allows the aircraft to remain aloft for a longer period of time
–Throttle: Adjust throttle to desired setting
–Mixture: Lean to peak Exhaust Gas Temperature (EGT)
Best Power – leaning for Best Power maximizes the aircrafts speed potential
–Throttle: Adjust throttle to desired setting
–Mixture: Lean to 50 F rich of peak EGT
–This is the recommended procedure by the Cessna PIM
Leaning
What does it do?
When do you lean?
Why do you lean?
Controlling the amount of fuel entering the carburetor for altitude or air density changes.
•When to Lean
–When operating at higher altitude (3,000 msl and above)
–At altitude, anytime there is a change in power setting
•Why Lean
–Air : Fuel Ratio must be correct (better performance)
When to Enrich Mixture (5)
–Full Throttle Operations –Descent –Close proximity to the ground –Traffic pattern operations –Engine Cooling
Fuel Injection System
What does it do?
What are the advantages? (5)
What are the disadvantages? (2)
Injector Nozzles spray fuel directly into intake manifold at cylinders
•Advantages –Better Cold Starts –Improved Performance –More efficient fuel distribution –Vaporization Ice problem removed
•Disadvantages
–Vapor Lock – difficulty starting engine when hot
–Plugged Injectors due to contamination
Oil Distribution - Wet Sump
What kind of aircraft is it for?
Name a specific aircraft that uses Wet Sump
How is it fed?
- Mostly for non-aerobatic aircraft
- C172S
- Gravity Fed
Oil Distribution - Dry Sump
What kind of aircraft is it for?
•Common among aerobatic aircraft
Oil System - Preflight
Oil Type (3)
Oil Quantity?
Oil Type
–Mineral – Used with a new engine
–Ashless Dispersant
–Synthetic
•Oil Quantity
–5-8qt
Cooling System
What are the effects of High Temperature Ops? (3)
Effects of High Temperature Operations
–Power Loss
–Excessive Oil Consumption
–Engine Damage
Types of Cooling Systems (2)
Additional Cooling Methods (3)
- Air (C172)
- Liquid
Additional Cooling Methods
–Increase Airspeed
–Enrich Mixture
–Decrease Power
Propeller
What’s it’s purpose?
What types are there? (3)
What type does the C172 have?
Purpose – converts engine torque into forward thrust
•Types
–Fixed Pitch – C172
–Controllable – blade angle can be changed in flight
–Constant Speed – blade angle changes automatically based on speed (RPM) set by pilot
Propeller Governor
What does it do?
What are it’s two functions.
Applies to constant speed propeller system
–Senses when the propeller is either too fast or too slow
–Uses engine oil to regulate the blade angle to maintain a desired speed (RPM)
•Changes blade pitch
Propeller Design Features (2) and what do they provide?
Pitch Angle of Blade
–For more power or more efficiency
•Blade Twist
–Compensates for the fact that the outward part of the blade travels a greater distance through the air than the hob of the blade does.
–Equal Thrust
Propeller - Pre-Flight (4)
Should you rotate prop by hand?
•Nicks •Secured to Crankshaft •Oil Leaks •Check Operation –Should you rotate by hand? NO
Propeller - Good Operating Practices (3)
Avoid operating above the red line
–2700 RPM
•Follow manufacturer’s recommendations
•Consider operating surface
–FOD
–Grass
–Ice
Fuel System - Types (2)
Gravity Type – gravity pulls fuel from the tanks down into engine
–Typical of high wing aircraft
•Pump – fuel is pumped from tanks to engine
Fuel System - Components (6)
•Tanks
•Pumps (2 total in C172)
–Engine Driven
–Electric Powered (auxiliary)
- Drains
- Vent
- Primer
•Gauges
–Fuel Quantity
–Fuel Pressure/Flow
C172 Fuel System
Total Capacity?
Unusable fuel?
Usable fuel?
What types of fuel pump are there?
Total capacity: 56 gallons
- Unusable fuel: 3 gallons
- Usable fuel: 53 gallons
•2 fuel pumps
–Electric
–Engine driven
Fuel System - Types of Fuel (4)
Alternate fuels?
AVGAS 80 - RED
AVGAS 100 - GREEN
AVGAS 100LL - BLUE
JET A - Colorless or Straw
Alternate Fuels
–Substitutions
•May use higher grade, NEVER LOWER!
Abnormality: Pre-Ignition
Definition?
Causes?
Signs of pre-ignition?
Solution?
•Ignition caused in advance of normal power stroke
•Usually resulting from hot spots in cylinder, caused by…
–Glowing deposits of lead (hot spots)
–Overheated spark plugs
–High power settings with excessively lean mixture
–More common in rear cylinders, due to reduced cooling
•Signs of Pre-Ignition
–Rough Running Engine
–Backfiring
–Rise in engine temperatures
•Solution – Reduce Engine Temperature
Abnormality Detonation:
•Occurs when the fuel/air mixture explodes in cylinder
–The fuel/air mixture should burn, not explode
–Typically occurs in all cylinders
•Characterized by:
–Excessive engine operating temperature
–Excessive Cylinder Head Temperature (CHT)
Fuel System - Good Practices (7)
- Check all fuel drains during preflight
- Keep tanks full during storage
- Use Higher Octane fuel if necessary, NEVER LOWER
- Electrically ground airplane during refueling
- Keep fuel vents clear of debris
- Visually check tanks for amount of fuel
- After fueling, wait 5 minutes before sumping
Fuel System - C172 POH Notes
When can you operate left or right tank.
Takeoff and landing settings?
Low fuel (1/4 or less) restriction
•Cessna 172
–Operation on either LEFT or RIGHT tank limited to level flight only
–Takeoff and land with the fuel selector valve handle in the BOTH position
–With ¼ tank or less, prolonged uncoordinated flight is prohibited when operating on either left or right tank
Fuel Emergencies (5)
- Check Fuel Selector
- Check Boost Pump
- Check Mixture
- Check Primer
- Check Fuel Gauges/Fuel Flow/Pressure
Hydraulic System - Components (7)
•Components of typical Hydraulic System -
–Fluid - MIL-H-5606
–Reservoir: source of fluid
–Pump: moves fluid
–Actuator: changes fluid pressure into mechanical action
–Valves: control fluid flow
–Lines: transfer fluid
Hydraulic System Examples (4)
- Wheel Brakes
- Retractable Landing Gear
- Constant Speed Propellers
- Flight Control Surfaces (Flaps, Ailerons, Spoilers)
Hydraulic Systems - Malfunctions (2)
•Slow operation
•Fluid leaks
–Hydraulic fluid is red
–During preflight, inspect the ground around the brake caliper.
Electrical System - Fundamentals
Volt and AMP indicate what?
Sources of Power:
Primary source of power?
What creates charge?
- VOLT = Pressure
- AMP = Volume (How much system can take)
•Sources of Power
–Battery – chemical reaction creates charge
- Provides power to start aircraft (MASTER BAT)
- Back-up source of power (Standby BAT)
•C172: 24 volt
–Alternator – mechanical action creates charge
•Primary source of power in-flight
•C172: 28 volt 60 amp
–Standby battery – used only when both the alternator and main battery can no longer supply power
Circuit Breakers - (3)
What is it made from?
What does it do ?
Is it reusable?
- Thermo magnetic type
- Protect electrical components from damage
- Reusable (fuses are not)
Fuses (2)
- Secondary method to protecting electrical components
* Modern aircraft may still have fuses but are only accessible in the engine compartment
Electrical System - Ammeter
What does it do?
What is a load meter and what does it do?
•Shows battery rate of charge or discharge
•Load Meter
–Type of ammeter
–Indicates total electrical load on system at any given time
–If all electrical components are off, indicates charging rate of the battery
Electrical System - Buses (2)
What are the buses? (5)
- Power Distribution Points
- Allows for the isolation and organization of electrical sources and components
Essential Bus
Electrical Bus 1 & 2
Crossfeed Bus
Avionics Bus 1&2
C172: Low/High Voltage
Low volts annunciator indicates what and when is it triggered?
High volts annunciator triggered when?
What is corrective action?
•“LOW VOLTS” annunciator
–Triggered when power is below 24.5 volts
•Indication of an alternator failure
•“HIGH VOLTS” annunciator
–Triggered when power is at or above 32.0 volts.
- Indication that the alternator is supplying too high of a voltage and that pilot action is required
- Reference the aircraft checklist for corrective action
Vacuum System
What gyroscopic instruments does it supply air to?
•Supplies air for 2 out of 3 Gyroscopic Instruments (non-glass)
–Attitude Indicator
–Heading Indicator
–Not Turn Coordination-it’s electric
•C172: Backup attitude indicator is only vacuum powered instrument
Vacuum System - Components (8)
PIECES PF
- Pressure Switch
- Instruments
- Engine Driven Vacuum Pump
- Check Valve
- Electrical Vacuum Pump
- Suction Gauge
- Plumbing
- Filter
Vacuum System - Preflight (2)
- Verify proper vacuum pressure during engine run-up and no annunciator
- Verify operation of Air Gyroscopic Instruments
Vacuum System - Malfunctions (1)
What do you check?
•Low pressure –Check Annunciator –Check vacuum pressure gauge –Increase Engine Power –Auxiliary Vacuum
Flight Controls - Preflight (4)
•Can flight control surfaces be damaged during preflight?
- Check for correct operation and free movement
- Check attach points for security
•Check for condition of exterior control surface
–Dents, dings, bends, crack, etc…
•Can flight control surfaces be damaged during preflight?
Yes, sometimes maintenance can fix quickly sometimes it makes the aircraft unworthy.
Environmental Systems -
What is it?
What are sources of heat?
What are the dangers?
•Heating System
–Sources of Heat •Exhaust Manifold •Combustion Heater –Dangers Associated with Heating Systems •Carbon Monoxide •Fire •Ventilation System
Ice Protection Systems
•Types of Icing
–Structural Icing: What we see on leading edges and tail.
–Induction Icing: Occurs in the carbeurater ice. Carb heat aids.
•Anti-ice vs. Deice
–Anti-ice is designed to prevent any type of ice from adhering to aircraft surfaces
•Typically heated surfaces are Anti-Ice
–Deice is designed to remove ice from aircraft once it has accumulated
•Examples: Pneumatic Boots and Weeping Wings
•Light general aviation aircraft typically only have:
–Pitot heat
–Carburetor heat
–Window defrost
•Ice Protection on aircraft certified for flight into icing conditions
–Pneumatic Boots
–Hot Props
- Weeping Wing – fluid flows from small holes in wing melting ice on surface
- Heated Surfaces
Pitot Source Blocked
Indicated Airspeed does what?
Indicated Altitude does what?
Indicated Vertical Speed does what?
Indicated Airspeed- Increases with altitude gain; decreases with altitude loss
Indicated Altitude-Unaffected
Indicated Vertical Speed-Unaffected
One Static Source Blocked
Inaccurate while sideslipping; extremely sensitive in turbulence
Both Static Sources Blocked
Indicated Airspeed-Decreases with altitude gain; increases with altitude loss.
Indicated Altitude-Does not change with actual gain or loss of altitude.
Indicated Vertical Speed-Does not change with actual variations in vertical speed.
Both Static and Pitot Sources Blocked
All indications remain constant, regardless of actual changes in airspeed, altitude and vertical speed.
Inadvertent Door Opening
• Concentrate on flying the airplane.
*Particularly in light single- and twin-engine airplanes; a cabin door that opens in flight seldom if ever compromises the airplane’s ability to fly. There may be some handling effects such as roll and/or yaw, but in most instances these can be easily overcome.
• If the door opens after lift-off, do not rush to land.
*Climb to normal traffic pattern altitude, fly a nor- mal traffic pattern, and make a normal landing.
- Do not release the seat belt and shoulder harness in an attempt to reach the door. Leave the door alone. Land as soon as practicable, and close the door once safely on the ground.
- Remember that most doors will not stay wide open. They will usually bang open, then settle partly closed. A slip towards the door may cause it to open wider; a slip away from the door may push it closed.
- Do not panic. Try to ignore the unfamiliar noise and vibration. Also, do not rush. Attempting to get the airplane on the ground as quickly as pos- sible may result in steep turns at low altitude
- Complete all items on the landing checklist.
- Remember that accidents are almost never caused by an open door. Rather, an open door accident is caused by the pilot’s distraction or failure to maintain control of the airplane.
Aircraft System Hydraulic (2)
–Brakes
–Flight controls
Aircraft System Electrical (3)
–Avionics
–Lights
–Flaps
Aircraft System Mechanical (1)
–Flight Controls
Aircraft System Pneumatic (3)
–Flight Instruments
–Ice Protection
–Environmental
Aircraft System Combustion (2)
–Heater
–Engine power
Engine Types (2)
–Reciprocating
–Turbine
Engine Operation - Stroke Cycles(4)
Intake
Compression
Power
Exhaust
Cylinder Arrangement Types (4)
Radial (circle around propeller)
In-Line (Lined Up)
V (like a car engine)
Horizontally Opposed (IO)
Engine Controls (2)
- Throttle
- Mixture
Gearing
What does it connect?
What are the two types?
Connection between the engine and propeller
–Direct Drive – propeller is connected directly to crankshaft
–Gear Reduction – propeller is connected to crankshaft through a series of reduction gears
Engine Instruments (9)
TMOOFFCEV
- Tachometer
- Manifold Pressure
- Oil Temperature
- Oil Pressure
- Fuel Quantity
- Fuel Pressure – Fuel Flow
- Cylinder Head Temperature (CHT)
- Exhaust Gas Temperature (EGT)
- Vacuum Pressure
Ignition System - Components (3)
- Magnetos
- Spark Plugs
- Wiring Harness
Purpose of Magnetos (2)
Does it need electricity from electrical system?
- Generates electricity for spark plugs from engine rotation.
- Distributes electricity to each spark plug at the proper time.
–Does not need electricity from electrical system
Purpose of Dual Magneto System (2)
- Provides Safety – Redundant Backup
* Enhances Performance – Two sparks per cylinder instead of one
Magneto Check Before and After Flight
Before Takeoff:
Before Shut Down:
•Before Takeoff –Check each of the two magnetos by selecting them individually using the key –Maximum RPM Drop: •Cessna 172: 175 RPM –Maximum Differential RPM: •Cessna 172: 50 RPM
•Before Shutdown
–Quickly turn key to OFF and back to BOTH.
–This ensures the magnetos are properly grounded
Exhaust System - Components (2)
- Manifolds
* Muffler
Induction System
Normally Aspirated:
Air Intake:
Types: (2)
What does a turbocharged Induction System do?
•Normally Aspirated
–Outside air is fed directly into the engine
–Same air pressure
•Air Intake
–Preflight: Ensure it is open and clear
•Types:
–Carburetion
–Fuel injected
•Turbocharged Induction System
–Pressurizing the air before it enters the cylinders
Carburetor Icing (4 Facts)
- As air passes through the venturi of the carburetor it’s pressure decreases and velocity increases.
- This combined with the atomization of fuel creates a cooling effect in the carburetor.
- Air naturally contains water vapor, which freezes to the sides of the venturi under certain conditions.
- The phenomenon is known as Carburetor Icing.
Signs of Carburetor Icing (3)
- Reduction in RPM
- Engine Roughness
- Fuel Starvation
Carburetor Heat (5)
- Solution to Carburetor Icing is to apply Carburetor Heat.
- Carb Heat is controlled by the pilot in the cockpit.
- When in the on position, hot air is ducted from the exhaust manifold and into the Carburetor.
- Hot air melts the ice lining the carburetor.
- Always apply full heat.
Side Effects of Using Carburetor Heat (3)
- Enriches Mixture
- If ice is present the engine will typically get worse before it gets better. The ice will melt into water which will be taken into the cylinders.
- Carburetor Heat is unfiltered
Favorable Conditions for Carburetor Icing
2
•High Humidity
–Small Temperature / Dewpoint Spread
•Temperatures between 20ºF to 80ºF
Left Turning Tendency Causes (4)
- Torque – Propeller rotates clockwise as seen from cockpit. The propeller is connected via crankshaft to engine connected to airplane. The equal and opposite reaction creates left turning tendency.
- P-Factor – when pitch of the aircraft increases the propeller orientation also changes. As you pitch up, the descending blade has higher angle of attack into relative wind while backward moving propeller has lower angle of attack during turns. Descending blade creates more thrust.
- Spiral Slipstream – propeller rotates clockwise, that rotation wraps around the airfoil and strikes the tail.
- Gyroscopic Procession – when a gyro is rotated at a high speed, the gyro tends to maintain it’s orientation in space. Based on the principle of GP a force applied toa gyro acts 90 degrees in the direction of rotation.
Aircraft Airframe Components (5)
- Fuselage
- Empennage
- Powerplant
- Wings
- Landing Gear
Aircraft Systems (5)
- Pneumatic
- Hydraulic
- Mechanical
- Combustion
- Electrical
