Final Review Flashcards
What is the atmosphere made of?
78% Nitrogen, 21% Oxygen, 1% Other
Effect of temperature on the atmosphere
affects the density of the air because when air is heated it expands
Effect of humidity on the atmosphere
affects the density of the air because water vapor is less dense than air
Effect of altitude on the atmosphere
affects the density of the air because there are fewer air molecules the further up you go
What is Standard Day?
59 degrees F
Sea level
Zero humidity
41 deg. N Lat.
Four forces
Thrust, Lift, Drag, Weight
Thrust
Thrust is a mechanical force generated by the engines to move the aircraft through the air
Lift
Lift is a mechanical force generated by a solid object moving through a fluid
Newton’s 3rd Law Applies: For every action there is an equal and opposite reaction
Drag
Drag is a mechanical force generated by a solid object moving through a fluid
Newton’s 1st Law Applies The Law of Inertia: If a body is at rest or moving at a constant speed in a straight line, it will remain at rest or keep moving in a straight line at constant speed unless it is acted upon by a force
Weight
Weight is a force caused by the gravitational attraction of the Earth
If the 4 forces are balanced …
the aircraft cruises at constant velocity and altitude
If the forces are unbalanced
the aircraft accelerates in the direction of the largest force
Bernoulli’s Principle
As the velocity of a fluid increases the pressure exerted by the fluid decreases
Coanda Effect (Downwash)
A moving stream of fluid in contact with a curved surface will tend to follow the curvature of the surface rather than continue traveling in a straight line
LIFT acts upward from the
Center of Pressure
WEIGHT acts downward from the
Center of Gravity
Changing Camber
increasing the angle that the wing meets the air
Changing Lift
The higher the AOA, the greater velocity of the air, and smaller area of the wing exposed the faster air
Parts of an airfoil
Leading edge, Chord line, Upper camber, Trailing edge, Lower camber, Angle of Attack (AOA)
Dihedral
angle of angle of wing from plane to wing tip
Mean Camber Line
refers to an imaginary line, created mathematically, when you subtract the distance from the chord line to the lower camber from the distance from the chord line to the upper camber
Lift Equation
L = CL½V2Sρ
Types of Drag
Parasite, Induced, Profile
Parasite Drag
The drag produced by air flowing over the surfaces not involved in producing lift
Induced Drag
The part of the drag of an airfoil caused by the lift, that is, the change in the direction of the airflow
Profile Drag
Parasite Drag of the airfoil
Stall
occurs when the angle of attack of an aerofoil exceeds the value which creates maximum lift as a consequence of airflow across it
Can happen at any speed
Drag Equation
D = CD½V2Sρ
Airfoil
shaped surface, such as an airplane wing, tail, or propeller blade, that produces lift and drag when moved through the air. An airfoil produces a lifting force that acts at right angles to the airstream and a dragging force that acts in the same direction as the airstream
Why were early designs of the airfoil ditched?
Various minor setbacks
Transonic Airfoil
Reduces air velocity over upper surface and delays the drag that occurs near the speed of sound
Ground Effect
When an aircraft flies less than one-half its wingspan above the ground
Boundary Layer
causes an increase in drag
Wing Fences
Prevent the entire wing from stalling at once
Vortex Genrators
Small airfoils installed in pairs
Planform
Factors that affect the shape of the wing: purpose, load factors, speeds, construction costs, maintenance costs, maneuverability and stability
Sweepback Planform
Efficient at high speeds (near speed of sound)
Can get Dutch roll- plane keeps yawing back and forth
Need a yaw damper to prevent Dutch roll
Stall from wingtips first
Delays shock waves- aircraft can fly closer to the speed of sound
Unfavorable at slow airspeeds- most sweptwing planes have extensive leading and trailing edge flaps to compensate
Basic Parts of plane
Fuselage: The “body” of an aircraft
Empenage: the whole tail assembly
Nacelle (Powerplant): engine and mounting location
Wings: provides the majority of the lift an airplane requires for flight
Landing Gear (Struts): absorb the impact of the landing
Fuselage sections
longeron, skin, former, bulkhead, firewall, stringer
Wing Sections
skin, ribs, spar, stringers
Measurement stations
Fuselage (datum), wing (butt line), waterline (waterline)
Winglets
Located at the end of each wing, its purpose is to reduce the drag
Landing gear types
Conventional, Tricycle, Bicycle, Quadricycle, Main, Auxiliary
Antenna
Size and rotation corresponding to the type of work being received or transmitted
GPS antenna is always mounted to the top of an airplane. This is because the GPA satellites are in Space
Generally: longer antennas are used for radio communication and navigation (VHF frequencies), while shorter antennas are reserved for higher frequency data
control surface vs. primary vs. secondary flight control
Control Surface: A movable airfoil, or any surface used to control the aircraft in flight
Primary Flight Controls: Elevator, rudder, ailerons
Secondary Flight Controls: Modify the effects of the primary flight controls or air flows
Aileron Control
Move stick or yoke left and right
Slips vs. Skids
Slips: Deliberate skids are used in aerobatics and aerial combat
Skids: Deliberate slips done with vigorous application of roll and opposite rudder can be used as a dive brake
Adverse Yaw
the aircraft may roll one way but directionally turn the opposite
Flaps
a “high lift / high drag” device
Slats
“High lift” device typically found on jets
Trim Tabs
Secondary flight controls, which modify the position of the primary flight controls
Used to get flight control settings just right
Flight vs. Ground Spoilers
Flight: Deflect a small amount to reduce the lift on one wing at a time. Often hooked into the plane’s primary flight control system to help control roll at the ailerons
Ground: The primary purpose of the ground spoilers is to maximize wheel brake efficiency by “spoiling” or dumping the lift generated by the wing and thus forcing the full weight of the aircraft onto the landing gear
Speed Brakes
used to create drag to slow the airplane
Piston vs. Turbine Engines
Piston: Utilize heat energy to produce the power for propulsion
Turbine: Turbofan jet engine propulsion system
Potential vs. Kinetic
Potential: Energy of position or stored energy
Kinetic: Energy of motion
Chemical energy (fuel) to heat (combustion) to mechanical (rotation) =
Thrust
Positive G’s vs. Negative G’s
Positive: Makes you feel heavier
Negative: Makes you feel lighter
Categories of a/c
normal, utility, and acrobatic
Static vs. Dynamic Stability
Static: Does the object attempt to return to its null, or home, or level position if displaced
Dynamic: Describes how its null, or home, or level position if displaced
Positive vs. Neutral vs. Negative Stability
Positive: May wander around, but eventually settles on home
Neutral: Equilibrium encountered at any point of displacement
Negative: Tendency to continue in displacement direction (away from home)
Dihedral vs. Anhedral
Sad Anhedral Plane
Happy Dihedral Plane
How do sweepback wings increase yaw stability?
The wing approaches the air at an angle and gives the air more time to climb up the camber
Slightly less effective at making lift
The wing moving backward has less frontal area and not in straight relative wind produces more life and more induced drag
The wing moving forward presents more frontal area straight into the wind: lift and induced drag decrease
Flap Types
Plain Flap: Simply hinge the trailing edge downward
Split Flap: A flap which simply hinges a lower portion of the wing open
Slotted Flap: The hinge of the trailing edge leaves a gap between the wing and the flap
Fowler Flap: Tucks up inside the wing when retracted
Slotted Fowler Flap: Fowler flaps with multiple slots
Leading Edge Devices
Droop Leading Edge: Lowers the AOA and Gives the wing a higher camber as the air sees it
Kreuger Flaps: Lower the AOA, increase camber, Make a more rounded leading edge
Aspect Ratio of Wing
Gives the wings characteristics of a higher aspect ratio
Anything you can do to prevent the airflow from under the wing from rolling off the tip of the wing and creating a rolling vortex makes the wing seem to have a higher aspect ratio
Bernoulli’s principal is no longer valid at supersonic speeds. Why?
Bernoulli’s Principle assumes that air is not compressible
Compressibility of Air
As airflow approaches sonic speeds, air becomes a compressible fluid
Speed of Sound
Aircraft speed: 0 mph = Speed of Sound: 760 mph
Aircraft speed: 200 mph = Speed of Sound: 560 mph
Aircraft speed: 760 mph = Speed of Sound: 0 mph
Sonic Boom
shockwaves traveling faster than the speed of sound
Mach Number
The speed of the aircraft in relation to the speed of sound
Different regions of sonic flight
subsonic, transonic, sonic, supersonic, hypersonic
Transonic Region
begins with the first evidence of sonic or supersonic flow around the aircraft anywhere
Critical Mach Number
The speed in localized areas around the aircraft are supersonic though the aircraft is still subsonic
Normal vs. Oblique Shock Waves
Normal: Occurs in front of a supersonic object if the flow is turned by a large amount and the shock cannot remain attached to the body
Oblique: Generated by the nose and by the leading edge of the wing and tail of a supersonic aircraft
How is lift made at supersonic speed?
Lift is generated only by the angle of attack
Parts of a Helicopter
Rotor Mast, Tail Rotor, Vertical Stabilizer, Engine & Transmission, Landing Skids, Cockpit, Main Rotor
What do the four forces do in a hover and flight
In a hover, all four forces are acting vertically
In directional flight, the forces separate
Collective Stick
increases AOA of blades collectively
Cyclic Stick
Controls movement forward
Swash Plate Operation
What the controls of a helicopter go through
Droop vs. Coning
Droop: Blades bend down
Coning: Blades bend up
What keeps the blades level?
Centrifugal force
Anti-Torque Pedal
Controls the tail rotor
Controling an Anti-Torque Pedal
To face left push on the left anti-torque pedal
To face right push on the right anti-torque pedal
Fenestron
greatly reduces injuries due to people running into tail rotors, and reduces accidents where tail rotors strike objects
Ways to eliminate a tail rotor
The two rotors on a tandem rotor helicopter rotate in opposite directions
What are tandem rotor helicopters?
aircraft that have two main rotors and no tail rotor
Having two rotors eliminates need for tail rotor
Airspeed _________ across the blade from the root to the tip.
increases
3 problems in getting helicopters to fly
- Dissymmetry of Lift & Gyroscopic Precision
- Coriolis Effect (“ice skater” effect)
- Lead-lag movement caused by massive vibration
How does a fully articulated rotor head solve the 3 main problems?
- Flapping hinges
- Lead-lag hinges
- Lead-lag dampeners
Difference between fully articulated rotors, semi-rigid rotors, and rigid rotors
Fully Articulated: have both flapping and lead-lag hinges
Semi-Rigid: has a lead-lag hinge, but no flapping hinge
Rigid: there are no hinges in the rotor blades
Gyroscopic procession
any force put into a spinning object takes effect 90 degrees later
What is the difference between highest blade angle vs. highest disc angle
Highest blade angle is 90 degrees clockwise to the highest disc angle
Why don’t we use pure aluminum as a material in aviation?
Pure aluminum is used as a “combination item” for other materials (i.e., iron)
What is the most common alloy in aviation?
Al 2024
What is the principal aluminum alloy for Al 2024? (anything 2XXX)
copper
What does grain size mean?
A metal’s strength
AC 43.13 1B
Advisory circular (AC) that contains methods, techniques, and practices deemed “acceptable”
How would you identify what rivet to use?
by the loads imposed on the structure and by the manufacturer and the information found in the manufacturer’s Structural Repair Manual (SRM)
What happens once the metal parts are cut and shaped to the form desired?
they must be drilled and deburred to prepare for the rivet or fasteners to be installed
What is different in installing a rivet if it is flush-mount?
Hi-Lok fasteners are used instead
Parts of a bolt
Head: top part
Shank: bottom part
Grip: top smooth part of shank
Threads: bottom rough part of shank
Where is torque applied on a bolt/nut fastener?
Torque is applied to the bolt/nut
Safety devices
Safety wire
Cotter pins
What can safety wire secure?
Nuts
Bolts
Oil filters
Cannon plugs
Anything that must not loosen during normal operations
What is the difference between brazing and soldering?
Brazing uses higher temps than soldering
Differences between MIG (Gas Metal Arc (GMAW)) and TIG (Tungsten Inert Gas) welding
MIG uses wire
TIG uses electricity
What is a Type Certificate (TC)?
When the design of an aircraft meets the FAA’s standards
What is a Type Certificate Data Sheet (TCDS)?
FAA document that records the type certification data of a product
What is an Airworthiness Certificate?
Certificate issued for aircraft that are good to go
What is in a TCDS?
Control surface movement limits, operating limitations, placards, and weight and balance, engines allowed, propellors allowed
Supplemental Type Certificate (STC) vs. Parts Manufacture Approval (PMA) vs. Technical
Standard Order (TSO)
STC: approval of the modification of the aircraft, engine, or propeller
PMA: FAA approval of the manufacture only of non-commonly interchangeable parts on an aircraft
TSO: FAA approval of the design and manufacture of commonly interchangeable parts on an aircraft
Standard vs. Special Airworthiness Certificates
What categories are in each?
Standard: normal, utility, acrobatic, commuter, transport, & manned free balloons
Special: primary, restricted, limited, light-sport, provisional airworthiness certificates, special flight permits, and experimental certificates
Major repair and Form 337
request for engineering approval for the modification to an individual aircraft
Airworthiness Directives
issued by the FAA and must be complied with
The owner or operator is responsible for knowing and complying with airworthiness directives
Advisory Circular
produced by the FAA and compliance is voluntary
Service Bulletins
Issued by aircraft and component manufactures to inform the owners about potential problems with the aircraft
Compliance is not required
Mandatory Service Bulletins
Issued when a manufacturer, insurance companies, or the FAA want to try to force the aircraft owner to comply
Compliance is not required
Service Letters
Sent by manufacturers as a means of providing non-critical information, or for clarifying maintenance manuals or pilot handbooks
Compliance is not required
Maintenace Manuals
Written by the manufacturer and approved by the FAA
Compliance is required
Minimum Equipment List
The master minimum equipment list is developed by the aircraft manufacturer and approved by the FAA
Compliance with the MEL is required
Operation Specifications
Created by commercial airlines that is submitted to the FAA for approval
Compliance is required
Manufacturer’s data supersedes any other source of information except what?
airworthiness directives
ATA (Air Transport Association) Codes
Developed to standardize the order of maintenance manuals
The ATA code should always be expressed as a _____ part number
three
What do each of the following numbers represent in the ATA code?
26-22-03
26: Chapter/System (Universal on all aircraft)
22: Subsystem (Universal on all aircraft)
03: Unit in the subsystem (Can be defined by individual airline, manufacturer, or uses)
Data plate
Contains the serial number of the aircraft
Is considered to theoretically BE the aircraft
If an airplane is scrapped, Unless the data plate is scrapped the aircraft theoretically still exists
What must maintenance records include?
description of the work performed
date of completion of the work
signature and certificate number of the person approving the aircraft for return to service
the Total Aircraft time and time on life-limited parts
Current status of ADs
Aircraft ownership =
“Bill of sale”
Liens
Documents against the airplane recorded by the FAA
What is the difference between a license and a certificate
Licenses must be periodically renewed. Certificates do not
Offenses involving alcohol or drugs
Denial of an application for any certificate up to 1 year
Suspension or revocation of any certificate
Temporary Certificate
Issued until your permanent certificate arrives
Security Disqualifications
Security Disqualifications
Don’t do these on a written test
Copy or remove the test
Give or receive part of a copied test
Give or receive help while it is being given
Take the test for another person
Take part in any other form of cheating
Change of Adress rules
Within 30 days after any change in his permanent mailing address, the holder of a certificate issued under this part shall notify
Refusal to submit to a drug test
Denial of an application for any certificate up to 1 year
Suspension or revocation of any certificate
Eligibly Requirements
Must be 16 years old, and be able to read, write, speak, and understand English
