GAK Exam Revision Flashcards
What are the gases that make up most of the atmosphere? (4)
Nitrogen - 78%
Oxygen - 21%
Argon - 1%
Carbon Dioxide - <1%
What is ISA?
15°C mean sea level temperature
- 25 hPa mean sea level pressure
- 98°C/1,000ft temperature lapse rate
What is the ISA height of the tropopause?
36,090ft
How do temperature and pressure change with respect to altitude?
Both temperature and pressure increase with altitude
What is the rate of change of pressure with altitude? (where is it greater/lesser)
Air pressure reduces with altitude most rapidly in the lower atmosphere
What are the 4 fundamental forces acting on aircraft in flight?
Lift
Weight
Thrust
Drag
What are 4 factors that affect lift?
Airflow velocity
Air density
Surface area of the wing
Wing shape and angle of attack
What is the angle of attack?
The angle between the chord line and the relative airflow
What is the centre of pressure?
The point from which lift in said to act from
What is the centre of gravity?
The point through the total weight of the aircraft is said to act
If airspeed is reduced in level flight what must you do to maintain level flight?
Increase the angle of attack by pitching the nose of the aircraft up
What happens when the angle of attack of the wing is beyond the critical angle?
Airflow can no longer conform to the curvature of the wing and the aircraft will stall
How does a pilot recover from a stall?
By pitching the nose down the angle of attack can be decreased to allow air to smoothly flow over the surface of the wing and initiate lift
Define stalling speed
The speed below which an aircraft in clean configuration can no longer maintain straight and level flight
To accelerate in a climb what must you do with thrust?
Thrust is increased and must remain greater than drag
Define mach number
The at which an aircraft is travelling in relation to the speed of sound
What does sweepback on a wing achieve?
The swept back wings delay the formation of shockwaves
Define asymmetric flight
In one engine fails in multi-engine aircraft the other has considerable leverage and induces unwanted yaw
What do flaps do?
Flaps increase lift
- increase wing area by extending from the front or rear of the wing
- increase the camber of the wing
- delays airflow separation by channeling higher energy air over the surface of the wing from below the wing
What can affect the amount of lift a wing generates?
Flaps
Slats
What are the different types of drag?
Parasitic drag
Zero lift drag
Induced drag
Lift dependent drag
What is the 4-stroke engine cycle?
Intake Compression Power Exhaust (suck, squeeze, bang, blow)
What are the implication for ATC for a piston engine aircraft?
These aircraft descend at no more than 500ft/min due:
- thermal shock
- generally not pressurized
Name the parts and processes of a turbine engine (jet/gas turbine)
Parts
- air inlet
- combustion chambers
- turbine
Process
- intake
- compression
- combustion
- exhaust
What is the relationship between fuel efficiency and altitude?
Maximum fuel efficiency is achieved at eh highest possible altitude because of the reduced drag of the lower density air
Name the axes of rotation and the movement associated with them
Longitudinal - roll
Lateral - pitch
Vertical - yaw
What are trim tabs?
A small hinged surfafce usually on the traliing edge of a primary control surface. They hold the control surfaces at an angle of deflection when a balancing force is required. most aircraft have trim devices for elevators, ailerons and rudder
Name the control surfaces and lift augmentation devices from a diagram
Ailerons
Rudder
Elevators
Define altitude, height, elevation
Altitude
- the vertical distance of a level or a point measured from mean sea level
Elevation
- the vertical distance of a point or level on or fixed to the surface of the earth measured from mean sea level
Height
- The vertical distance of a level or point measured from a specific datum including the vertical dimension of the object
Define level
A generic term relating to the postion of an aircraft in flight and meaning height, altitude of flight level
Pressure/Density altitude calculations
Pressure altitude
(QNE - QNH) x 30 + field elevation
Density Altitude
Adjusted ISA temp. = 15 - (2n) where n is the number of 1000s of feet from mean sea level (measured to P/ALT) (round result to nearest 500ft (1° per 500ft))
(Actual temp - adjusted ISA temp) x 120 + P/ALT
What is the transition layer?
The transition layer is a buffer zone between the transition altitude and level where no aircraft are permitted to to cruise to ensure separation while aircraft are transitioning to different altimeter readings
What is the transition level and altitude in NZ?
Where all aircraft will switch their altimeters to read QNH 1013 when climbing so that all aircraft at higher altitudes read the same error, or switch to area QNH when descending through to get a more accurate reading closer to the ground
Transition alt - 13,000ft (A130)
Transition level - FL150
What are the errors associated with barometric altimeters and how can a pilot adjust for them?
A barometric altimeter will not indicate correctly if the actual sea level pressure differs from the ISA value is was calibrated to
Every altimter is fixed with a pressure setting sub-scale that allow the actual sea level pressure to be set as the zero datum
Define IAS and TAS
IAS
- indicated air speed; the direct instrument indication that the pilot reads on the face of the instrument
TAS
- true air speed; The speed which the aircraft is actually moving through the surrounding air
What is the realtionship between IAS and TAS?
As altitude increases TRAS much faster than IAS due to decreased air desnity
What are the main controls on a helicopter?
Cyclic
Collective
Torque pedals
How can a helicopter stall?
Retreating blade stall
- increasing the angle of attack of the rotors too much causes the helicopter to roll towards the retreating blade
What are the proximity warning systems acrinyms?
GPWS - ground proximity warning system TAWS - terrain awareness system TCAS - traffic alert and collision avoidance system STCA - short term conflict alert MSAW - minimum safe altitude warning
What are the average rates of climb and speed for different engine types?
Jets
- 2,500-3,000ft per minute which reduces with altitude
- 250-300kt
Turboprops
- 1,500ft per minute
- 160-180kt
What are the avergae cruising speeds for different engine types?
Jets
- mach 0.78-0.85M
Turboprops
- 250kt
What is the relationship between speed and turn radius?
The greater the speed the greater the turn radius
What is wake turbulence?
Cosists of wake vortices formed any time an aircraft wing is producing lift. Act as a spring holding the aircraft back and disrupts the air training the aircraft in a spinning motion
What is wake turbulence dependent on?
Weight
Wingspan
Configuration
What weather conditions cause wake turbulence to be more dangerous?
Light winds cause the wake turbulence to stay in approach and runway touchdown areas, drift to parallel runways or sink into landing/take off paths of succeeding aircraft
What are the types of aircraft icing?
Rime
Clear
Hoar frost (aircraft on ground overnight)
What types of clouds are condusive to icing?
Cumulus Cb Altocumulus Nimbostratus Altostratus
What parts of an aircraft would be affected by icing?
Wing and tail surfaces Propellers Radio antennae Sensors Windshields Engine (carb icing)
What are the 4 aquaplaning descriptors?
Damp - surfaces changes colour due to moisture
Wet - surface is soaked but there is no standing water
Water patches - patches of standing water are visible
Flooded - extensive standing water is visible
Define wind shear
A change in wind speed and/or direction over a short distance
List 3 common sources of wind shear
Frontal activity
Thunderstorms
Temperature inversions
Microbursts
