Exam 3 Flashcards
Source that the pilot controls and which will allow sufficient operation of electrical equipment should the generator fail.
Primary Power
Engine driven device (alternator or generator) which generates power to supply all normal loads and charge the battery
Generated Power
An alternate power source that is arranged so that it is available to the pilot, even if the aircraft battery is dead (the 152 does not have one!).
Auxiliary Power
Strips of copper with holes drilled in them at appropriate intervals which are connected to one side of a row of circuit breakers and to incoming power
Busbars
Remove power from a component if the circuit becomes overloaded
Circuit Breakers
Perform basically the same function as a circuit breaker, but cannot be reset
Fuses
Used in an electric circuit for protection and current control.
Resistors
Electron “check valves”that allow the flow of electrons in one direction, but not in the opposite direction.
Diodes
Used to control the availability of power to various components.
Switches
Found in electrical systems to drive fuel booster pumps, flaps, etc.
Motors
Used exclusively in pitot tubes, windshield heat, etc.
Heating Elements
Used in flap switches and act in the same manner as normal switches.
Micro-Switches
Remote controlled electrical switches.
Relays
Lead acid
Battery
Completes the electrical circuit, which closes or opens the battery relay.
Masterswitch
Shows the rate of charge or discharge from the battery
Ammeter
Displays the load or amp draw placed on the alternator.
•Battery
•Electrical Equipment
Load Meter
A solenoid that when closed will supply electrical power to the starter.
Starter Relay
Completes an electrical circuit, which closes or opens the starter relay.
Starter Switch
Rotates the crankshaft for engine start.
Starter Motor
for reciprocating engines FAR’s Require the following:
- Two separate spark plugs for each cylinder
* Two separate circuits and sources of electrical energy, supplying spark to each cylinder.
Magneto Ignition System Operating Principals
- The magneto system consists of a rotating magnet and the core of the magneto coil.
- The rotating magnet is a permanent magnet.
- The core of the magneto coil is a conductor.
- As the magneto rotates, the core of the magneto coil cuts the lines of flux in the magnet, thereby inducing EMF in the core.
Consists of the primary winding of the coil, the breaker points, the capacitor, and the ignition switch.
Primary Circuit
Consists of approx 200 turns of copper wire wound over the core.
Primary Windings
Opens and closes the circuit of the coil and is timed to produce a maximum buildup and then release of the magnetic field.
Breaker Point
Acts as a storage chamber to absorb the sudden rise in voltage in the coil when the breaker is open.
•Voltage can be amplified by a change in the primary windings.
Condenser
Consists of the secondary winding of the coil, the distributor, the ignition harness, and the spark plugs.
Secondary Electrical System
Center of the distributor rotor.
High Voltage Contact
Will distribute the voltage to the ignition harness (spark plug lead).
Distributor Rotor
Will distribute the spark to the spark plug.
•Ignition harnesses are made of stranded copper or stainless steel, surrounded by rubber insulation.
Ignition Harnesses
Braided stainless steel that surrounds the insulation: this is necessary to prevent loss of engine performance and interference in electronic equipment.
Shielding
- Spark plugs provide an insulated electrical source inside the combustion chamber.
- A high voltage is applied so that a spark jumps from the electrode to the ground.
- Spark plugs are subjected to voltages in excess of 18,000 volts, gas temps as high as 3,000 F, and pressures from partial vacuum to 2,000psi!
- In a 100 hr operating period a spark plug is required to ignite 7,000,000 times.
Info about Spark Plugs
Types of Spark Plugs
- Shielded Massive Electrode-Has three-pronged insert on the firing end from which the spark jumps to the ground.
- Shielded Fine Wire-Has a center electrode and two ground electrodes.
Electrical Power
- Primary Power
- Generated Power
- Auxiliary Power
any substance which tends to flow and conform to the outline of it container.
Fluid
Moves liquids under pressure to perform work. Commonly used in the operation of brakes, landing gear, flaps, struts, shock absorbers, shimmy dampeners, etc.
Hydraulic System
Uses the movement of a fluid to perform work, but once the fluid has been displaced, its energy in the systems is lost (water wheel). pertaining to hydraulics
Open System
Fluid is confined in such a way that its pressure may be increased to perform work (car jack, barber chair, brakes, etc.). pertaining to hydraulics
Closed System
PneumaticAdvantage
Moves gas or air under pressure to perform work.
Fluid Mechanics Definitions
- Force-Energy exerted that is the cause of motion or change.
- Pressure-When a force is applied over a given area.
- Work-When a force causes an object to move.
- Volume-Base of a container in square units times its height in the same units.
- Work-Product of force x distance.
- Power-Rate of work, or the work accomplished in a give amount of time.
energy is found in one of two forms:
Kinetic-Exists in an object due to its motion.(Expressed as velocity.)
Potential (Static)-Exists in an object due to its position or pressure.-(Expressed as pressure.)
Pressure in an enclosed container is transmitted equally and undiminished to all parts of the container and acts at right angles to the enclosing walls.
Pascal’s Law
As the velocity of a fluid increases, its internal pressure decreases.
Bernoulli’s Principle
Hydraulic Fluid Characteristics
- Be as incompressible as possible.
- Flow freely with minimal friction.
- Be compatible with components of the aircraft.
- Good lubricating properties.
- Not foam during operation.
Types of Hydraulic Fluids
- Vegetable Based
- Mineral Based
- Synthetic Based
Hydraulic System Components
- Pump - Heart of the hydraulic system.
- Reservoir - Stores fluid for the system and serves as an expansion chamber where the system can purge itself of air accumulated in the operational cycle.
- Fluid Lines - Made of aluminum alloy, are considered rigid, where synthetic rubber lines are considered flexible lines.
- Actuator - Converts pressure in the fluid to work.
Type of aircraft brakes
- Energizing Brakes
- Non-Energizing Brakes
- Brake Actuating System
Drum type brakes. Not used today because of modern disc type brakes, which have fewer moving parts and dissipates heat more rapidly.
Energizing Brakes
Disc brakes.
•Single disc type.
•Disc is rigidly mounted to the wheel and hydraulic pressure applies a squeezing action between the fixed linings and rotating disc.
Non-Energizing Brakes
Pre-flighting the Hydraulic System
- Ensure the proper level of fluid is present in the various hydraulic systems.
- Check for leaks around all fittings.
5 Structural Components
- Fuselage
- Wings
- Stabilizers
- Flight Control Surfaces
- Landing Gear
Uses struts and wire bracing to achieve strength.
High Drag and weight.
Truss Type Structure
No internal framework, all loads are carried in the skin
Monocoque
Uses an internal framework of formers and stringers to add strength and rigidity to the skin.
Semi-Monocoque
Five stresses acting on an airplane.
- Tension-Tries to pull a body apart.
- Compression-Tries to squeeze parts together.
- Bending-Tries to pull one side of the body apart and squeeze the other side together.
- Torsion-Twisting force
- Shear-Tries to slide a body apart.
Materials Used in Aircraft Construction
- Wood-Solid or laminated wood was the construction medium of preference in early aircraft.
- Aluminum Alloy-Offers a lightweight, durable construction medium
- Composites-New exotic plastics offer a lightweight construction material with ease of workmanship.
Used to enhance lateral stability
Dihedral
increasing the angle of incidence in the wing.
Wash-In
Decreasing the angle of incidence in the wing.
Wash-Out
Varying the angle of incidence within the wing enhances stall characteristics.
Twist
4 types of Wing Alignment
Dihedral
Wash-In
Wash-Out
Twist
Makes sure the center of mass for a flight control is on or slightly ahead of the hinge point.
Mass Balancing
Gains rigidity in control surface skin.
Corrugation
Primary Flight Controls
- Pitch Control
- Bank/Roll Control
- Directional/Yaw Control
Moveable control surface attached to horizontal stabilizer.
•Typically seen in high wings where there is greater downwash.
Elevator-pitch control
Entire horizontal stabilizer is pivoted about its main spar.
Stabilator-pitch control
used to roll the airplane about the longitudinal axis
Ailerons-roll control
Help to counteract adverse yaw by moving the up aileron up more the down aileron moves down (increasing PD).
Differential Ailerons
Location of hinge point causes the leading edge portion of the aileron to extend into the relative wind to increase parasite drag and counteract adverse yaw.
Frise Ailerons
Secondary (Auxiliary) Flight Controls
Trim Tabs Balance Tabs Anti-Servo Tab Servo-Tab Fixed Trim Tab
Small moveable portions of the trailing edge of the control surface.
Trim Tabs
Operate similar to trim tabs, except the control tab rod is connected to a fixed surface.
Balance Tabs
Used on stabilator equipped aircraft.
Anti-Servo Tab
Used on large aircraft with heavy control surfaces.
Servo-Tab
Small piece of metal affixed to the trailing edge of a flight control.
Fixed Trim Tab
Auxiliary Lift Devices
Trailing Edge Flaps-Allow the aircraft to fly a steeper glidepath without an increase in airspeed.
•Plain•Split•Slotted•Fowler
Leading Edge Lift Devices
•Leading Edge Flaps•Slots•Slats•Stall Strips
Other Lift Devices
•Winglets, Tip Tanks, Droop Tips.•Vortex Generators
Enhance boundary layer control at higher speeds.
Vortex Generators
Why is Weight & Balance important?
-A properly loaded aircraft is a safe aircraft.
-Manufacturers test for safe limits for loading for certification
Maximum takeoff and landing weights
Center of Gravity limits forward and aft
Structural Limits
The center of balance of all components of the mass or an imaginary point
where the aircraft would balance if suspended.
Center Of Gravity (CG)
Imaginary vertical plane, in which all horizontal distances are measured for weight and balance, set by the manufacturer.
Datum
The horizontal distance of any object measured from the datum
Arm
A rotational force caused by weight acting on an arm. Weight X Arm =
Moment
Weight of standard airplane, optional equipment, unusable fuel, and full
operating fluids.
Basic Empty Weight
Fuel that cannot be consumed by the engine, undrainable fuel
Unusable Fuel
A comprehensive list of equipment installed on a particular aircraft,
including optional equipment
Equipment List
Aircraft weight loaded for flight prior to engine start, limit referred as
Ramp weight
Subtract the weight of fuel burned during start, taxi, runup, weight just prior to takeoff
Max Takeoff weight
Takeoff weight minus the weight of fuel burned in flight, limit sometimes referred as
Max Landing Weight
Weight of flight crew, usable fuel, any passengers, baggage and cargo. Basic empty weight minus ramp weight or takeoff weight
Useful Load
Weight of only passengers, baggage and cargo
Payload
Effects of Center of Gravity -Forward CG Effects
Increases download on tail(+TDF)
Slower Cruise speed
Nose up trim is required (Heavier Elevator controls)
Higher Stall Speed(increased wing loading)
Harder to rotate on takeoff/flare on landing
Effects of Center of Gravity -Aft CG Effects
Decreases download on tail(-TDF)
Higher Cruise Speed
Less nose up trim(Lighter Elevator controls), poor stability, nose wanders up and down
Lower stall speed(decreased wing loading)
Harder stall recovery, may lead to flat spin!!!
Effects of Operating at a High Total Weight
Taxi speed should be reduced – larger aircraft causes high tire/brake temperatures
Longer takeoff rolls and higher speeds higher density altitude may not be able to takeoff at certain weights
Angle and Rate of Climb are Reduced
Unable to obtain higher cruise altitudes
Range and speed are reduced at cruise
Higher fuel consumption
Stalls at a higher speed
Longer landing distance and higher touchdown speed carry less weight to meet landing requirements
Increased brake wear and temperatures
Pressure Measuring Instruments (Pitot Static Instruments)
- ASI
- VSI
- Altimeter
Typically installed on wing of SE aircraft outside of slipstream.
Pitot Tube
Typically flush mounted to side of fuselage.
Static Ports
Usually installed in static lines and should be drained prior to flight.
Water Traps
May be located on or under instrument panel and for pressurized aircraft, static air is taken from inside the cabin behind instrument panel.
Alternate Static Source
May be used to remove or prevent the formation of ice on the pitot tube.
Pitot Heat
Components of Pitot Static Instruments
Pitot Tube Static Ports Water Traps Alternate Static Source Pitot Heat
Caused by static ports sensing erroneous static pressure measurements.
•Slip
•Skid
•Configuration(landing gear, flaps etc)
Position Error
Caused by changes in altitude and temperature for which the instrument does not automatically compensate.
Density Error
Caused by packing of air into pitot tube at higher airspeeds, resulting in higher than normal readings.
Compressibility Error
Airspeed Errors
Position Error
Density Error
Compressibility Error
Instrument Blockage
Types of Airspeed
Indicated Airspeed
Calibrated airspeed
Equivalent airspeed
True airspeed
Indicated Airspeed
Read from instrument.Remains the same with an increase in altitude.
Calibrated airspeed
Indicated corrected for instrument and installation error.
Equivalent airspeed
Calibrated corrected for adiabatic compressibility for a given altitude.
True airspeed
Airspeed relative to undisturbed air.
Aneroid barometer calibrated in feet instead of inches Hg.
Altimeter
Types of Altitude
- Absolute Altitude-AGL
- True Altitude-MSL
- Calibrated Altitude-Altitude corrected for instrument and installation errors.
- Indicated Altitude-Read directly from altimeter (uncorrected).
- Pressure Altitude-Altitude indicated when altimeter is set to standard datum plane (29.92).
- Density Altitude-Pressure altitude corrected for non-standard temperature.
- Indicates whether aircraft is climbing, descending, or in level flight.
- Indicates rate and trend of climb.
- Automatically compensates for temperature.
Vertical Speed Indicator
GYROSCOPIC INSTRUMENTS
- Attitude Indicator
- Heading Indicator
- Turn Coordinator
Wheel or disc designed to utilize gyroscopic principles based upon Newton’s Laws of Motion.
Gyroscope
Mountings of the gyro wheels.
Gimbals
Any friction applies a deflecting force to a gyro.
Bearing Friction
Factors affecting gyroscopic inertia:
- Weight-Heavier mass for a given size is more resistant to disturbing forces.
- Angular Force-higher velocity = greater rigidity.
- Radius at which the Weight is Concentrated-maximum effect when weight is concentrated near the rim.
Resultant action or deflection of a spinning wheel when a deflective force is applied to its rim (
Precession
Eliminates errors of magnetic compass while providing a consistently reliable source of heading information.
Heading Indicator
Heading Indicator Errors
- Misuse of Magnetic compass when setting the DG.
2. Random Drift-Caused by friction and slight imbalances in the gyro and gimbal.
Combination of two instruments to sense aircraft movement about the yaw and roll axes.
Turn Coordinator
Turn Coordinator Errors
- Insufficient or excessive rotor speed.
2. Inaccurate adjustment of the calibrating spring.
