Exam Revision Flashcards

Question 1

Q

Great circles

except on direct

any point on earth

Answer

A

From any point to point on the earth there is a great circle that is the quickest route to it (except if they are on the direct opposite ends of the earth where there are infinite great circles)

Question 2

Q

Latitude is measured along

Answer

A

the x-axis or horizontally

Question 3

Q

whereas longitude is measured

Answer

A

vertically or on the y axis

Question 4

Q

lines of latitude and longitude measured in

Answer

A

degrees (o) minutes (‘) and seconds (“)

Question 5

Q

where there is

how many mins in degree

Answer

A

60 minutes in a degree and 60 seconds in a minute

Question 6

Q

Wind Velocity

Answer

A

Is the speed and direction of the wind in knots (direction is named from where it is coming from)

Question 7

Q

Directions

Answer

A

Are expressed in 3 figures (e.g. north = 000)

Question 8

Q

Heading

Answer

A

Is the direction the aircraft is pointed towards

Question 9

Q

Track

Answer

A

Is the direction the aircraft is actually taking

Question 10

Q

Flight Planned Track

Answer

A

Is the path that the pilot intends to take over the ground

Question 11

Q

Track Made Good

Answer

A

The actual path travelled by the aircraft over the ground

Question 12

Q

Drift

Answer

A

Is the angle between heading and track made good

Question 13

Q

Track Error

Answer

A

The angle between heading and track made good

Question 14

Q

Track To Intercept

Answer

A

Is the track you need to get back onto the track

Question 15

Q

Closed angle

Answer

A

Is the angle between the original planned track and the new track to intercept

Question 16

Q

True airspeed

Answer

A

The speed of the aircraft relative to the air (e.g. like a headwind takes TAS down)

Question 17

Q

Indicated airspeed

Answer

A

The speed which the plane is traveling displayed on the airspeed indicator

Question 18

Q

Calibrated airspeed

Answer

A

is IAS corrected for instrumentation/ position errors (corrects any error created by the aircraft deflecting air)

Question 19

Q

ground speed

Answer

A

The speed of the aircraft relative to the ground

Question 20

Q

Load factor formula

Answer

A

Load factor = 1 / COS (angle of bank)

Question 21

Q

New stall speed formula

Answer

A

old stall speed * (load factor)^1/2

Question 22

Q

stalled spin recovery (P.A.R.E)

Answer

A

o (P) ower idle,
o (A) ilerons neutral,
o (R) udder opposite the spin, and
o [E] levator back.

Question 23

Q

spiral dive recovery

Answer

A

o reducing power (to idle),
o leveling the wings with ailerons,
o gradually pulling up on the elevator while adding power if necessary.

Question 24

Q

Lateral stability

high winged aircrafts:

Answer

A

In a high wing winged aircraft
o CoG of the fuselage will counteract the direction of a roll bringing the plane back to wings level
In a low wing aircraft
o COG of fuselage will assist the plane in direction of the roll, will put the plane into a steeper bank

Question 25

Q

Lateral stability

For an aircraft with dihedral wings:

The three steps

higher AOA

sideslip RAF

Answer

A

Due to sideslip of relative airflow due to the roll, the lower wing will experience a higher angle of attack
The higher angle of attack will automatically produce more lift in the lower wing than the higher wing
The lower wing will lift and will want to bring the aircraft back to level flight.

Question 26

Q

Lateral stability

swept back wings

Answer

A

When the aircraft rolls, sideslip of relative airflow will mean the lower wing’s leading edge will be close to 90o to relative airflow compared to the upper wing which will have a far less direct angle of airflow to leading edge. The more direct airflow will lead to more lift created on the lower wing, bringing the aircraft back to wings level. Chord wise flow is most effective flow
Because of the sideslip the front section of the fuselage will block some airflow over the upper wing, reducing it’s effective span for creating lift. The lower wing will experience more lift (because of more span exposed to airflow) creating more lift bringing the wings back to level flight.

Question 27

Q

Directional stability

Drag

fuselage blocks area

Answer

A

When an aircraft yaws in one direction, the forward wing opposite the direction of yaw offers more frontal area to the relative airflow, creating more drag. The backward wing, blocked by some of the fuselage experiences less frontal area to the airflow and experiences less drag. The wing with more drag has an automatic effect of yawing the aircraft back to centre

Question 28

Q

Directional stability

what does it mean

Answer

A

When a directionally stable aircraft yaws it will return to straight ahead flight without any use of the rudder

Question 29

Q

Directional stability

vertical fin

moment
surface area

Answer

A

The fin of an aircraft has an inbuilt ability to recover from a yawing disturbance about the normal axis. The moment of the vertical fin, due to large surface area and moment due to the large distance between it and the centre of gravity, acts to restore the nose to its original position

Question 30

Q

Longitudinal stability

Horizontal stabilizer

airflow

lift tail

greatest contributer

Answer

A

The greatest contributor to restoring longitudinal stability is by the horizontal stabiliser. As an aircraft pitches upward, the airflow strikes the HS which are located behind the CoG. The airflow causes lift in the horizontal stabilisers, which lift the tail of the aircraft subsequently returning the nose of the aircraft to level (resisting the climb)… the same works in the opposite direction when the aircraft is descending.

Question 31

Q

Longitudinal stability

horizontal stabilisers having different angle of incidences

added affect

Answer

A

Longitudinal dihedral involves wings and horizontal stabilisers having different angle of incidences. By mounting the horizontal stabilisers at a higher angle of incidence, any change of angle of attack in the wing will have an added effect by the HS. Because of the position of the HS at the rear of the aircraft, any lift experienced by it will cause the tail to rise and nose of aircraft to fall, hence increasing longitudinal stability

Question 32

Q

Longitudinal stability

CoG

Answer

A

If the CoG is moved that leads to increased longitudinal stability. If moved Rearward CoG leads to decreased longitudinal stability. Pilot can arrange any cargo or weights within the aircraft to change position of CoG to suit.

Question 33

Q

Wheelbarrowing
Causes of wheelbarrowing:

Answer

A

Only occurs in aircraft with tricycle undercarriage
Landing too fast
Trying to force the front wheel onto the ground after landing causing too much load to - be on front wheel and not enough on the main wheels (rear)

Question 34

Q

Wheelbarrowing
Problems associated:

Answer

A

Loss of directional control of aircraft
Violent swerving as the aircraft pivots around the front wheel
Can cause ground strike of wing in direction of the wheelbarrowing or collapse of main wheel undercarriage due to excessive side loading.

Question 35

Q

Groundlooping
What aicraft does it occur in

Answer

A

Only occurs in aircraft with tailwheel undercarriage

Question 36

Q

Groundlooping

brakes applied

crosswind
overtake main wheels

Answer

A

Caused when aircraft lands in crosswind and tailwheel touches down sidewards of the aircraft… then the pilot applies brakes. Because tailwheel aircraft has CoG behind main wheels, the CoG and tailwheel can overtake the main wheels from the side, causing loss of directional control and wing strike.
After aircraft has landed but is still rolling at speed on runway, if pilot incorrectly applies brakes to one wheel only, can cause tail of aircraft to swing out. CoG of aircraft and tail wheel can overtake main wheels from the side causing wing strike.

Question 37

Q

Servo tab

Answer

A

Used due to high speed aircrafts as its to hard to pull and push control to get control so a variation is made in the trim tab in the opposite direction

Question 38

Q

Anti servo tab

Answer

A

Used with aircrafts that are to sensitive with the controls so the servo tab moves in the same directions as the controls

Question 39

Q

Trim tabs

manually

balanced

fixed

Answer

A

Fixed tabs need to be positioned manually by hand when the aircraft is on the ground before take-off.
A fixed tab on a single engine aircraft will normally be positioned so that the aircraft is balanced in cruise flight.
The trim tab moves in the opposite direction to the elevator, hence keeping the effect of the position of the elevator without the pilot having to feel the force of air against the control column.

Question 40

Q

Spoilers or lift dumpers

deployed individually or together

Answer

A

o Surfaces hinged to rise on the upper surface of the wing to reduce lift and create drag.
o If spoilers are deployed simultaneously, the loss of lift is symmetrical and aircraft decelerates and sinks
o If deployed individually, can be used as ailerons or aids for rolling the aircraft.

Question 41

Q

Spoilers or lift dumpers
Who uses them and for what reason?

Answer

A

o Glider pilots use spoilers or lift dumpers if they are approaching touchdown and they think they are going to overshoot the runway
o Airliners use spoilers to ensure the aircraft sits firmly on the runway after touchdown.

Question 42

Q

Anhedral

Answer

A

In summary, anhedral wings make the aircraft less laterally stable, or makes it easier for the pilot to roll the aircraft.
In a fighter jet, this is desirable so the aircraft can perform high performance manoeuvres
For a heavy lift cargo plane, most of the weight is located in fuselage, creating a pendulum effect to resist rolling motions. They may be so fuselage heavy that the aircraft cannot roll or bank, hence the anhedral wings help to maintain the aircraft in a roll.

Question 43

Q

Speed breaks

Answer

A

are surfaces that are deployed to create drag and cause rapid deacceleration in the aircraft.

Question 44

Q

Stabilators

Answer

A

Both horizontal stabilators and elevator.
In charge of pitching
High-speed aircraft, like an F-15 almost always have a stabilator because the elevator’s effectiveness at transonic speeds.

Question 45

Q

Tailerons

Used together by joystick or seperately

Answer

A

The fore and aft movement of the pilot’s joystick causes the tailerons to operate together, which in turn rotates the aircraft around it’s lateral axis, making them act like elevators and pitching the nose up and down

If the control column is moved sideways, the tailerons move differentially, with one taileron going up while the other going down. This causes the aircraft to rotates about its longitudinal axis, acting like ailerons to roll the aircraft.

Question 46

Q

Ruddervator

Answer

A

Combination of rudder and elevator.
In v shape and move up and down together to effect pitching and both move either the left or right simultaneously to cause yaw

Question 47

Q

Elevons

Answer

A

Both elevons move up and down together to control pitch
The elevons move in opposite directions to control roll
They combine these movements to conduct manoeuvres such as a climbing turn.

Question 48

Q

Flaperons

Answer

A

Flight control surface that combines flaps and ailerons.
Flaperons respond to roll commands via the yoke or joystick in the same way as normal ailerons
They can also be lowered to function as a dedicated set of flaps.
Advantage of using flaperons instead of dedicated ailerons and flaps is a reduction in weight.
Flaperons are a feature that are also common on aircraft designed for short take off and landing.

Question 49

Q

Canards

Answer

A

A small wing mounted either side of the nose of the aircraft
, it must be set at an angle of incidence that is greater than the wings of the aircraft
In an aircraft where a fixed canard is placed in front of the wing and C of G of the aircraft, if the wing stalls before the canard, the aircraft’s CoG will drop the wing and aircraft down pitching the nose up and further stalling the aircraft which can lead to an unrecoverable position.
A canard can serve two purposes;
o it can improve aircraft control, which you often see on combat aircraft. It also can contribute to lift, replacing the horizontal stabilizer and – theoretically - reducing overall drag.

Question 50

Q

High lift devices

Vortex generators

Answer

A

o are small plates about an inch deep standing on edge in a row spanwise along the wing.
o They are placed at an angle of attack and (like a wing airfoil section) generate vortices.
o These tend to prevent or delay the breakaway of the boundary layer by re-energizing it.

Question 51

Q

Flaps

Answer

A

o Decreases airspeed.
o Decreases distance to land.
o Increases angle of descent
o Increases rate of descent
o Increase forward visibility at low speeds.
o Located on the Trailing edge of a plane.
o Different types:
 Plain Flap
 Split Flap
 Slotted flap
 Fowler Flap
 Double Slotted Fowler Flap

Question 52

Q

Slots

Answer

A

o If you’re trying to decrease take off and landing distance, generating lots of lift at slow speeds is key
o Slots delay the stall by increasing the stalling angle of attack (called the critical angle of attack), often past 22 degrees.
o In aerodynamics, everything comes with a penalty. In a slot’s case, it’s drag, capping your airplane’s cruise speed and efficiency. Since slots are always open, the drag is always there at cruise speeds

Question 53

Q

Slats

Answer

A

o To solve the problem of slots, the retractable slat is used.
o Slats are extendable, high lift devices on the leading edge of the wings of some fixed wing aircraft.
o Their purpose is to increase lift during low speed operations such as take off, initial climb, approach and landing.
o They accomplish this by increasing both the surface area and the camber of the wing by deploying outwards and drooping downwards from the leading edge.
o Slats normally have several possible positions and extend progressively in concert with flap extension.

Question 54

Q

Climb with power:

Answer

A

In a climb at constant velocity, weight which acts towards the centre of the earth.
The component of W which acts against lift is WL.
Weight force also has a drag component represented by WD which acts against Thrust.
For the aircraft to be in constant velocity, all forces must be in equilibrium.
L = WL
T = D + WD
In plain English, it means Thrust (T) must equal Drag (D) + the Drag component of Weight (WD)

Question 55

Q

Glide descent

Answer

A

In a glide descent, thrust (T) is non-existent as engine is set to idle.
There is still a force counteracting Drag (D), otherwise the aircraft would be moving back up towards the sky which doesn’t make much physical sense.
The force that counteracts Drag is a component of Weight shown by WD.
For an aircraft to be gliding at constant velocity, all forces must be in equilibrium.
L = WL and.
D = WD

Question 56

Q

Decent with power

Answer

A

When an aircraft applies power during descent, thrust (T) is increased.
When T is increased, more air flows over the wings of the aircraft.
This will increase Lift (L).
If the nose of the aircraft is held down with power to keep airspeed constant, the increase in T will result in the aircraft rising due to increased L.
Very important to know this when learning how to land an aircraft.

Question 57

Q

Turn/load factor

Answer

A

Angle of bank (AoB) = angle that you turn
When the aircraft is banked, the component of Lift (LW) is less than total lift, so W > LW and the aircraft will descend.
During a turn, back pressure must be applied to keep the aircraft level. Backpressure creates additional lift during the turn.
To keep an aircraft from losing altitude during a turn, back pressure must be applied. The amount of force due to this backpressure is known as the ‘load factor’ which you will explore later. During a level turn, this is the amount of extra weight a person will feel in the aircraft.
LR can be worked out with the following formula:
Cos θ = LW / LR (how many G’s you are facing and LW is 1) e.g., AoB is 30 ° so Cos 30° = 1/ LR which Is also LR = 1/Cos 30° that means LR = 1.15 G’s

Question 58

Q

Induced airflow

Answer

A

is the air that is sucked in through the top of the rotor blades and blown out the bottom. Like a ceiling fan.
Increased induced airflow reduces angle of attack
Decreased Angle of attack = decreased lift
Just like an aircraft, if angle of attack is increased too much, the rotary blade will also stall

Question 59

Q

Coning:

Answer

A

the upward flexing of rotor blades resulting from the forces of lift distributed along the blades. The tips of the blades produce more lifting force than the roots.
As the rotor disc starts to take up the weight of the fuselage, the disc begins to cone.
This condition exists throughout all consequent phases of flight with some slight variations in extent due to changes in real and apparent weight or rotor speed.

Question 60

Q

Factors that can increase coning and cause a high coning angle include:

Answer

A

The RPM of the rotors (Low rotor RPM increases coning)
The weight of the vehicle (High gross weight increases coning)
Any G-forces experienced during flight (High G manoeuvres increases coning)

Question 61

Q

Excessive coning results in:

Answer

A

Undesirable stresses on the blades
A decrease in effective disk area and hence lift. Tip path plane decreases
An overall decrease in lift available
If the coning angle becomes too great, there is no chance of recovery, the blades fold upwards and you die.

Question 62

Q

Helicopter controls

3 ones what do they do

Answer

A

Collective pitch lever which causes the helicopter to rise and descend.
o Changes angle of pitch in rotor blades
The cyclic control which causes the helicopter to tilt in desired direction.
o Control the tilt of the rotor blades.
The tail rotor pedals which cause the helicopter to yaw.
o Change the pitch of the tail rotor and the thrust it produces

Question 63

Q

Swash plate

Answer

A

The swash plate assembly is the important link between the rotating rotor and both the cyclic pitch control and the collective pitch lever.
o It consists of two elements
The stationary element
The rotating element
o It is usually connected to three hydraulic rams which, when each is extended by the same amount, will keep the plate horizontal.
o When extended by different amounts, they will cause the plate to tilt.

Question 64

Q

There are 3 types of movement the rotor blades can do

Answer

A

Feathering
Flapping
Lead Lag

Answer 65

A

Longitudinal axis

Answer 66

A

normal axis (vertical)

Answer 67

A

lateral axis

Answer 68

A

Fully articulated rotor head
Teetering Rotor Head (Semi-rigid Rotor System)
Rigid Rotor Head

Answer 69

A

In a fully articulated head, each blade is attached to the rotor mast through a horizontal hinge (flapping hinge)
There are other hinges to allow for the other three blade movements (lead/lag and feathering) but the horizontal hinge is to allow flapping
The design allows each blade to flap independently

Answer 70

A

In a two-rotor blade system, the two blades share the one hinge on top of the mast.
In this case the blades do not flap independently, but as a single unit.
One side flaps up as the other flaps down.
The other hinges to allow lead/lag and feathering are still present on the teetering rotor head.

Answer 71

A

Mast bumping is the result of excessive rotor flapping with a teetering head design.
Each rotor system has a maximum flapping angle. If flapping exceeds the design value, the static stop (the teetering head) will contact the mast, which can cause catastrophic consequences.
Excessive flapping can occur due to severe turbulence or inappropriate control inputs. For example Low-G flight.

Answer 72

A

In this system the blade roots are rigidly attached to the rotor hub.
Rigid rotor systems behave like fully articulated systems through aerodynamics, but lack flapping or lead/lag hinges
Instead the blades accommodate these motions by bending.
They cannot flap or lead/lag but they can be feathered
Advantaged of a rigid head is for high performance helicopters. There is instant feedback from the controls to the chopper

Answer 73

A

or anti-torque rotor is designed to produce a force acting sideways and so prevent the fuselage from rotating in the opposite direction to the main rotor.
The tail rotor gearbox provides a right-angle drive for the tail rotor and may also include gearing to adjust output to an optimum tail rotor RPM (usually around 2 times that of the main rotor)

Answer 74

A

Coaxial Rotors a pair of helicopter rotors mounted one above the other on concentric shafts, with the same axis of rotation, but turning in opposite directions (contra-rotating).
Tandem rotors at longitudinal extremities: Tandem rotor helicopters have two large horizontal rotor assemblies mounted one in front of the other. Currently this configuration is mainly used for large cargo helicopters.

Answer 75

A

The rotor thrust upwards is greater than the weight and drag acting downwards creating the aircraft to ascend upwards.

Answer 76

A

The rotor thrust upwards is less than the weight and drag acting downwards creating the aircraft to descend downwards.

Answer 77

A

A helicopter can move horizontally forward, backwards and sideways. In order to do so the rotor disk is tilted in the desired direction of travel
It works just like an aeroplane with the vectors created as seen in the image on the right

Answer 78

A

GP means a force applied to a gyro (rotor disc) will produce an effect up to 90 degrees forward of the applied force.
Eg. If a rotor is spinning ACW, and you want to tilt it forward, the force on the disc required to do this needs to be applied up to 90 degs beforehand.
Helicopter controls are calibrated so the pilot does not need to think about it. Pilot just pushes forward if wants to tilt the disc forward and the swash plate is calibrated to make the correct movements to the rotor.

Answer 79

A

If a rotor spins ACW, fuselage of helicopter will spin CW (Newton’s 3rd law. Think of drill bit getting stuck)
This CW motion will also cause a sideways force to the right, shown at the rotor mast as drift.
Tail rotor provides anti-torque for fuselage which also causes a net sideways force to the right, show at the tail section.
These two forces provide an overall net movement of the helicopter to the right.

Answer 80

A

Pilot uses cyclic movement in opposite direction to TRD

Answer 81

A

Relative airflow is different on advancing side and retreating side of rotor disc
Compensated automatically in rotor system through flapping. Retreating side flaps down and advancing side flaps up.
This flapping causes relative airflow to be different on either side and consequently angle of attacks are different on either side.
Retreating side flaps down. Causes an increase in AoA, creating more lift, causing blade to flap back up.
Advancing side flaps up. Causes a decrease in AoA, diminishing lift, causing blade to flap back down.
This is called flapping to equality.

Answer 82

A

If flapping wasn’t allowed through the rotor system, DOL would cause FLAPBACK. The advancing side would produce more lift. Gyroscopic precession would transfer this increase in lift to the front of the helicopter (approx. 90 degs forward) causing uncontrollable rise to the nose…. Could be fatal.

Answer 83

A

As a helicopter moves forward, constant force must be applied to keep the disc tilted forward.
As helicopter moves faster, disc tilts more, causing retreating side to continually experience higher AoA than advancing side
Eventually AoA will exceed critical angle, causing retreating blade stall. The stall will be experienced at the rear of helicopter due to GP, causing severe vibration and pitching up!!
This is the cause of airspeed limitations on a helicopter.

Answer 84

A

As a helicopter moves forward, a force must be applied constantly to keep the disc tilted forwards as well as to compensate for any residual asymmetric lift.
The angle of attack on the retreating blade is always larger than the advancing blade because of the tilt.
As the helicopter moves faster, because of dissymmetry of lift, the retreating blade flaps down even further in the slower relative airflow and, angle of attack is subsequently increased… This happens to the point where angle of attack on the retreating side may reach critical angle at which point, the retreating blade will stall.
When this occurs the helicopter will experience severe vibration and pitch up. It may also roll.

Answer 85

A

Air entering to rear of rotor is accelerated to higher speed than front, causing greater downwash to rear section.
Greater downwash causes greater induced drag, reducing AoA to rear section
Reduced AoA in rear diminishes lift production in rear section.
GP causes this reduction in lift to be translated 90 degrees forward. (right side of rotor disc)
In a helicopter with ACW rotor rotation, results in a right drift

Answer 86

A

Pilot will use cyclic to counter effects of TFE

Answer 87

A

o Helicopter is operating in its own wingtip vortices, with tips of the blade ineffective at producing lift

Answer 88

A

o Rotor tilted forwards
o There is still some wingtip vortices but they are starting to get pushed away from rotor system by forward airflow causing rotor disc to receive greater efficiency.
o Bonus in lift from this. Same lift can be achieved with less engine power

Answer 89

A

o Helicopter has moved out of its wingtip vortices and into ETL
o Greater Lift can be produced with less power until 40 kts
o After 40 kts parasite drag from the fueslage negates ETL

Answer 90

A

Coriolis effect states that due to conservation of angular momentum, coning will cause the centre of mass of the blades to come closer to the mast, increases rotor RPM.
This increase in RPM, if not managed could overspeed the engine and cause damage to rotor and engine.

Answer 91

A

In semi rigid rotor systems, automatic flapping down of one side and up on the other diminishes the effect of Coriolis and avoids over-RPM of engine

Answer 92

A

In a fully articulated head with more than 2 blades, a drag hinge is used to allow backward and forward movement of blade
Retreating blade (flaps down, moves slower) lags, advancing blade (flaps up, moves faster) leads

Answer 93

A

When operating away from the ground, helicopter experiences recirculation of air at the blade tips
Similar to wingtip vortices in FW aircraft
This recirculation makes an area around the blade tip ineffective at producing lift.
When in ground effect (within a rotor span from ground) recirculation is disrupted and not allowed to flow back into the rotor system, so less of the blade tip is affected.
This results in bonus lift production IGE. Helicopters can seem to carry heavier loads when IGE and use less power to produce same amount of lift as when OGE.

Answer 94

A

If helicopter is operating IGE on top of a peak and accidentally drifts off the peak or ledge and ends up OGE, the helicopter will immediately lose lift.
If lift is not restored by raising collective, the helicopter will sink and possible collide with terrain.

Answer 95

A

Is the state of flight where rotor is driven by relative airflow rather than power of the engine.
Must be noted that the tail rotor also needs to be turning during autorotation to provide some counter to the frictional forces in the gearbox which would otherwise induce the fuselage to turn in the same direction.

Answer 96

A

When an engine failure occurs at low airspeed, pilot is required to:
o Disengage the rotor system from the engine.
o Lower the collective pitch to reduce pitch of blades to a minimum, reducing torque
o Nose is pushed down to give an angle of glide and to provide some translational lift

Answer 97

A

As the helicopter descends, the air coming up through the rotor disc causes the blades to rotate, and as they do, progressively store more energy.

Answer 98

A

When the ground approaches, the pilot:
o flares the helicopter in a similar manner to a normal landing and during this phase,
o the rotor will usually increase speed because of the flare.
o The final speed increase provides enough extra lift to arrest the helicopter’s descent.

Answer 99

A

At this stage the helicopter has lost its forward kinetic energy and has no air flowing upwards to keep the rotor turning.

Answer 100

A

As rotor speed decays, the helicopter settles on the ground, with the pilots last action:
o Extract the remaining lift from the rotor by increasing the collective pitch to its maximum.
o This increases the lift, but also increases the drag and the rotor quickly loses speed as the helicopter settles gently on the ground.

Answer 101

A

Published by manufacturer for their particular helicopter.
Depicts the combinations of speed and altitude in which operation of the helicopter is unsafe should an autorotation become necessary.
In the shaded regions, either height or the forward speed is too low to allow autorotation to be effected before the helicopter strikes the ground. These are the DEAD MAN ZONES

Answer 102

A

o Originate from the environment.
o Distractions from passengers
o Weather problems
o Heavy traffic
o System failures

Answer 103

A

o Brought to the cockpit in the person of the pilot and crew.
o Pilot fatigue
o Pilot experience and personality
o Health and fitness

Answer 104

A

o Would include such things as weather and heavy traffic or unfamiliar aerodromes.

Answer 105

A

o Would include such things as distractions from passengers, in-flight diversions and miss approaches.

Answer 106

A

o Are not directly obvious to the pilot but are lurking in the background waiting for a particular set of circumstances. They include such things as a ‘user unfriendly’ work environment such as a poor cockpit design or instrument design characteristics and company policies that do not adequately address proper maintenance issues or pilot fatigue and optical illusions as sloping runways or ‘black hole’ approaches.

Answer 107

A

o Exist due to the operating environment.
o Weather such as thunderstorms, icing, wind
o Terrain about and below the aircraft

Answer 108

A

o Originate from deficiencies in the infrastructure and organization in which the aircraft is operating.
o Documentation errors
o Tour of duty problems

Answer 109

A

o anything to do with actual manipulation of the aircraft controls.
o Rounding out too high or too late in landing
o failure to maintain height.
o Inappropriate use of power during approach

Answer 110

A

o Occur across whole spectrum of pilot experience. Often occur as consequence of external or internal threats such as time constraints, poor communication, distraction or poor-quality aerodrome markings or signage.
o failure to use written checklist for take-off or landing.
o failure to stop at holding point.

Answer 111

A

o ambiguous or misinterpreted communication.
o Use of non-standard phraseology in case of radio communication
o Poor quality radio reception
o Over transmission of radio messages by third party
o Unfamiliar foreign accents or rapid speech

Answer 112

A

o Aircraft control
o Placing aircraft in hazardous state
o Altitude, speed or track deviations
o Poor technique in flying
o Exceeding structural load

Answer 113

A

o Taxing too fast
o Wrong taxi way

Answer 114

A

o F)laps config
o W)eights balances
o F)uel
o A)utopilot
o G)PS

Answer 115

A

o Flight planning
o Pre-flight briefing

Answer 116

A

o Measures taken during flight
o Monitoring engine, flight and navigation instruments
o Cross checking information to ensure its integrity

Answer 117

A

o cope with unexpected contingencies which may arise during flight
o Evaluating and modifying
o Remaining alert

Answer 118

A

o anything built into the aircraft
o Stall warnings.
o System failures

Answer 119

A

as the strength of the indirect skywaves is greater at night, errors are more common and of greater magnitude at night.

Answer 120

A

when moving parallel to a coastline, NDB radio waves may be refracted (bent) due to the different conducting and reflecting properties of land and water. This causes false bearing indications: the NDB always appears closer to the coastline that it actually is.

Answer 121

A

thunderstorms generate considerable electromagnetic energy that may cause the ADF needle to swing from the direction of the received NDB signal to the direction of the centre of the electric storm

Answer 122

A

NDB radio signal have greater range over water than over sandy or mountainous country where the range is considerably reduced.

Answer 123

A

If radio signals are received from other NDB’s operating on the same or adjacent frequencies to the NDB tuned, the ADF may give false bearing information due to mixing of the signals.

Answer 124

A

is the force exerted on a given area.
- Pressure of 1013.2 hPa at sea level – 1 hPa per 30 feet in the lower atmosphere (up to about 5,000 feet).

Answer 125

A

Temperature of +15 °C - Temperature falls at a rate of 2 °C per 1,000 feet until the tropopause then constant at -57 °C.

Answer 126

A

is a varying height across the globe and separates the troposphere and the stratosphere.

Answer 127

A

are the lines in weather reports that display the differential in pressures.

Answer 128

A

o anticlockwise circulation.
o starts with cold air at high altitude which starts sinking.
o pressure at the surface rises (like pressure increases the further down in the ocean you go)
o Air in a high-pressure area compresses and warms as it descends.
o Clear day and stable conditions as no air rises

Answer 129

A

elongated area of high pressure extending along the axis.

Answer 130

A

o often strong winds. Unstable conditions due to air rising.
o Warm air at the surface becomes less dense and rises.
o the air at the surface flows in to fill the space left by the rising air.
o a clockwise direction.
o If there is sufficient vapour present to form large clouds, showers and rain areas develop.
o Weather associated with low pressure systems is often unstable and may be associated with rain and wind.
o Often a LOW will be associated with cloud cover.

Answer 131

A

opposite of a ridge an elongated area of low pressure

Answer 132

A

is a region between 2 highs that there are generally good flying conditions due to the lack of wind.

Answer 133

A

is a difference in air density, temperature, and cloud formation.

Answer 134

A

is represented as a solid line with spikes pointing in the direction of movement.
o Riser in atmospheric pressure
o Decrease in temperature.
o In a cold front warm air is being lifted
o Types of clouds that often come with a cold front is altocumulus, cumulus, and cumulonimbus.

Answer 135

A

are represented as a solid line with knobs off it pointing in the general direction that the front is heading in.
o Rise in temperature
o Decrease in atmospheric pressure.
o Types of clouds that can occur during a warm front can be nimbostratus altostratus and cirrostratus.

Answer 136

A

are only parts of day or night-time and confined to a particular area and this is due to unequal surface heating and cooling of earth’s surface.

Answer 137

A

is during the day when the land is hotter than the ocean so warm air rises, and the oceans cool breeze comes to fill the warm heating air.

Answer 138

A

is during the night-time when the land cools faster than the ocean and the warm air from the ocean rises and comes to fall on the land to fill the vacuum where the cooler air goes to fill the oceans vacuum.

Answer 139

A

are formed in the evenings and come down into valleys of slopes of the mountains, this is because the ground loses its heat fast, so air falls due to the rise in density to the temperature fall.

Answer 140

A

are often formed during the day and climb up hills and slopes. This is due to the ground heating up and the surface heating up so air rises up the mountains.

Answer 141

A

winds are when a wind forces itself up a mountain making it cool and become saturated and creating a cloud over the top of the mountain. the air reaches the lower slopes of the mountain, it is usually a warm dry wind and that is the foehn wind.

Answer 142

A

o Status meaning layer.
o Cumulus meaning a pile and a streak of clouds.
o Nimbus meaning rain cloud.
o cumulonimbus meaning a raining heap cloud.
o High clouds above 20,000 feet (cirr_____)
o Mid-level clouds 8,500-20,000feet (Alto______)
o Low clouds surface-8,500 feet (anything else)

Answer 143

A

eighths of sky covered horizontally.

Answer 144

A

vertical motions of stability within the atmosphere.

Answer 145

A

is when a parcel of air returns to its original position or level after having been disturbed.

Answer 146

A

is when a parcel of air is to rise to a high level than its origin after being disturbed.

Answer 147

A

is when the parcel neither returns to its original position nor moves furthered away from its new position.

Answer 148

A

o Describes the quantity of water vapour present in a particular volume or parcel of atmosphere.
o Measure of actual amount of water vapour as grams per kilogram of air.

Answer 149

A

o Measures how close the air is to saturation. Ratio of mass of water vapour present in a given parcel of air to the mass of water vapour which would cause saturation at the same temperature and pressure. Expressed as: %

Answer 150

A

is the temperature to which a parcel of air must be cooled at a constant pressure for it to become saturated.

Answer 151

A

cloud forms for a Varity of reasons such as convection, forced ascent, fronts and widespread ascent.

Answer 152

A

form when a parcel of air ascends as a result of being heated by the earth’s surface this often leads to the cloud formation of a cumulus or cumulonimbus clouds.

Answer 153

A

3 different reasons.

Answer 154

A

is when air moving over the irregular surface of the earth. This can lead to the formation of the cloud’s stratocumulus cloud or stratus.

Answer 155

A

is where clouds form as a consequence of air being forced to rise over mountains or hills. This often leads to the cloud stratus if the air is moist enough and is a stable atmosphere. Causes stratus or stratocumulus

Answer 156

A

is when clouds form when there is an interaction between two dissimilar air masses. When the warm and cold air meet the warm air moves over the cold air forming a wedge and the boundary of the 2 masses is called a cold front. Forms a Cumulonimbus or cumulus.

Answer 157

A

CI
HIGH
clouds are white patches of strings of narrow bands of clouds. (Thread like, like paint)

Answer 158

A

CS
HIGH
are transparent and totally or partially cover the sky. (Sheet or layer (halo phenomena))

Answer 159

A

CC
HIGH
are thin white layer, sheet or patch of clouds composed of very small elements in the forms of grains, ripples ect, irregularly arranged. (White and lumpy usually thin)

Answer 160

A

AS
MID
greyish bluish cloud sheet or layer of fibrous or uniform appearance. Partly revel the sun (sheet like)

Answer 161

A

AC
MID
white or grey clouds which have patches, sheets, or layers of clouds generally with shading. (Lumpy and heaped)

Answer 162

A

NS
LOW
are clouds which have a grey cloud layer often dark and drop snow or rain. They are thick enough to block out the sun. (Sheet layer STORMY

Answer 163

A

LOW
SC
are white, grey, or whitish patches, sheets or layers of clouds which have dark parts. (Patches and layers)

Answer 164

A

ST
LOW
have grey cloud layer with a uniform base, form in very low tempters and formed by radiation, turbulence, and orographic lifting. (Sheet layers)

Answer 165

A

CU
LOW
detached clouds which are dense with sharp outlines and have developed vertically in the form of rising mounds or domes (like a cauliflower) formed through thermal convection. (Flat base)

Answer 166

A

CB
ALL
are heavy and dense and form of a mountain or huge towers. The highest part of these clouds is often smoother and fibrous and always nearly flattened. Formed due to extreme thermal convection. (stormy)

Answer 167

A

A process which takes place where no heat transfer takes place between the environment and a parcel of air.

Answer 168

A

a temperature inversion is a narrow layer of the atmosphere where the temperature increases with height. inversions limit the vertical extent of clouds. no vertical movement of air so therefore flight conditions are still

Answer 169

A

o the rate at which temperature of the atmosphere changes with altitude is referred to as the environmental lapse rate.
o if temperature of atmosphere decreased with altitude then ELR is +ve.
o if temperature of atmosphere increase with altitude then ELR is -ve.

Answer 170

A

: a small parcel of rising air usually cools adiabatically at a value different to that of the ELR. if this parcel of air is unsaturated, the rate at which the temperature changes as the parcel ascends or descends through the atmosphere, is equivalent to 3 degrees per 1000 ft.

Answer 171

A

o when a parcel of air reaches the temperature at which the relative humidity reaches 100%, the air is said to be saturated. Is the parcel continues to rise past this level the water vapour condescends into droplets giving up latent heat.
o E.g This causes it to cool at a rate of 3 degrees per 1000ft, but is warmed at 1.5 degrees per 1000ft due to latent heat.

Answer 172

A

from high to low and the low is always to your right when the wind is coming to your back

Answer 173

A

are winds that follow the isobars. Under 3000ft or below
- If highs are in the bite of australia it is summer. If in the middle it is winter

Answer 174

A

o When wind has changed direction in ANTI-CLOCKWISE direction, it is said to have BACKED.
o When wind has changed direction in an CLOCKWISE direction, it is said to have VEERED.
o Easy acronym to remember this would be BA - VC

Answer 175

A

o Situated in Northern Australia
o Contains large amounts of moisture
o Considerable amount of precipitation in wet season [November - March]

Answer 176

A

o Tropical Pacific
 Moist and origins in Pacific Ocean
o Tropical Indian
 Moist originates in Indian Ocean
o Tropical Tasman
 Originates south of continent, cooler and contains less moisture than Pacific or Indian
o Tropical Continental
 Dry and forms a result of being modified as it passes over mainland Australia for extended periods of time

Answer 177

A

 Originates far south of continent and considered to be coldest of all air masses. Ice, snow and very cold winds may be associated with this air mass

Answer 178

A

 Originates as either a Polar Maritime or Indian ocean air mass. Generally cold and moist and affects southern part of continent

Answer 179

A

A cold front starts to develop when a body of advancing cold air encounters a region with warmer air.

Answer 180

A

As the frontal system approach, the air pressure continues to drop. It reaches its lowest point as the front passes and starts to climb again in its wake.

Answer 181

A

Cold air in the frontal system is much denser than the preceding warm air. As a result, the leading edge of the cold front easily pushes underneath the prevailing warmer air, lifting it into the atmosphere.

Answer 182

A

The speed and abruptness with which the warm air is forced to ascend, allow for the rapid condensation of water vapor and the formation of storm clouds.

Answer 183

A

This rapid development creates ideal conditions for the creation of heavy downpours and thunderstorms. It is in these storm systems that severe weather conditions such as hail, lightning, and thunder can occur.

Answer 184

A

Air temperatures also start to drop substantially as the cold front approaches, reaching its lowest point as the front passes. It remains cool as the body of cold air moves in behind the leading edge of the frontal system.

Answer 185

A

A warm front starts to develop when a body of advancing warmer air encounters a region with colder air.

Answer 186

A

Since warm air is less dense than the cold air, it cannot displace it. Instead, the leading edge of warmer mass gradually rises over the boundary of the prevailing cool air.

Answer 187

A

As the air continues to rise on the back of the colder air mass, it starts to cool down until the water vapor can no longer be contained in gaseous form, and condensation takes place.

Answer 188

A

The gentle gradient at which the air rises leads to the formation of uniform stratus clouds that are responsible for producing prolonged spells of soft precipitation.

Answer 189

A

As the warm front passes, the atmospheric conditions are characterized by warmer temperatures and a decrease in air pressure

Answer 190

A

o these are ROUTINE METEOROLOGICAL REPORTS made by a routine observer at a fixed times at a particular aerodrome.

Answer 191

A

 Routine Meteorological Report
 aerodrome (Wagga)
 DD/HHMM in UTC (Made at 2200Z on 9th day of month.)
 Wind direction then speed (030oT @ 02kts)
 Visibility (9km)
 Different weather information (Rain and showers have occurred since last report recently. [RE])
 Cloud cover
* (is 1-2 Oktas with base at 3000ft [FEW]
* 5-7 Oktas with base at 10000ft [BKN])
 Temperature/dew point (17/11)
 QNH (1012)
 Rainfall in last 10 min / since 0900 local (4.0mm / 10.0mm)

Answer 192

A

o When conditions at an aerodrome fluctuate about or are below certain specified criteria, the aerodrome report has its name changed from METAR to SPECI.
o As far as the pilot is concerned, nothing but the name has changed in the way you read the report.
o However, when the report is prefixed SPECI, it is likely to contain information of greater operational significance.

Answer 193

A

o pilots telling the meteorologists what is happening in the air.
o These aircraft provide this information in the form of an AIREP
o Even general aviation pilots may give short AIREPS to pass on any information that may be of value to the MET station or other pilots.
o An AIREP would normally be sent from an aircraft if a pilot encountered:
 Cloud which is significantly different from the forecast
 Visibility reductions due to fog, mist, hail, rain, snow or dust
 Wind velocities which are very different from those forecast
 Un-forecasted phenomena such as moderate or severe turbulence, thunderstorms, icing, hail or line squalls

Answer 194

A

o Visibility of 10km or more
o No cloud below 5000ft and no CB cloud at any height
o No significant weather

Answer 195

A

o Terminal area forecast
o Forecast periods last for 6, 12, 18, 24 or 30 hours.
o Larger the airport the larger the validity period

Answer 196

A

 Terminal area forecast
 Airport
 10th @ 1845 UTC
 Valid from 1020 to 1108
 Wind coming from 250 with wind 05 knots
 Visibility 9km
 Scatted clouds @ 2000 ft
 Scatted clouds at 4500
 Temperature 21 17 15 14
 QNH 1019 1020 1020 1019

Answer 197

A

o Hammer
o Anvil
o Stirrup

Answer 198

A

o 25mm long canal which stops at eardrum.
o Hairs in canal with 4000 wax producing cells to prevent dust and bugs from flying down your ear.

Answer 199

A

o Eardrum has a seal around it protecting from the outer atmosphere.
o Eardrum vibrates to sound waves arriving via the canal.
o The three tiny bones hammer, anvil and stirrup amplify vibrations to cochlea.
o Stirrup connects to the cochlea at the oval window.
o This where vibrations turned from mechanical to electric pulses
o The pulses are then carried to the brain via the cochlea nerve.
o The middle of the ear is vented to the atmosphere by the eustachian tube which connects to the upper part of the throat.
o Air flows to and from the middle ear via the eustachian tube to equalise the air pressure on either side of the eardrum.

Answer 200

A

o The cochlea processes vibrations arriving at the oval window converting them to electric signals.
o Above the cochlea are the semicircular canals which detect acceleration in pitch, roll and yaw.
o They are our sense of balance.
o The cochlea is a small bony structure that looks like a snail shell.
o Filled with liquid called endolymph and tiny hairs that move when pressure waves pass through which generate nerve impulses which brain interprets as sound.
o Loud sounds such as gunshot can permanent damage inside of ear

Answer 201

A

o The semicircular canals are three hollow loops located at the top of the cochlea.
o It is filled with endolymph and hairs called cupula.
o As the head/body changes speed or altitude in space the fluid washes over the hairlike cells-which respond by sending nerve impulse to the brain
o The cupula only responds to the initial change in angles not a constant turn (like a rate 2- turn)

Answer 202

A

o Otolith organ sense linear accelerations it is located at the top of the cochlea.
* Utricle - lies horizontally and detects horizontal accelerations.
* Saccule - lies vertically picking up vertical accelerations.

Answer 203

A

Pressure on soles of feet when standing or on seat and back when seated.

Answer 204

A

Human ear copes comfortably up to 80dB
o Above this, produces discomfort and long term exposure can cause permanent damage

Answer 205

A

o Above 140dB produces ear pain.
o 120dB ear discomfort
o Above 85dB ear protection should be worn.

Answer 206

A

Deafness begins at higher frequencies first, above that of normal speech.

Answer 207

A

which you need to shout to be heard at a distance of half a metre.

Answer 208

A

o increase stress levels
o Reduces concentration
o Aggravates fatigue
o Leads to general reduction in efficiency

Answer 209

A

is a transparent film through which light first enters the eye. It focuses the light onto the retina.

Answer 210

A

is the fluid in the cornea that supports it.

Answer 211

A

us the colour part of the eye that changes shape depending on the intensity of light. This causes the pupil to become larger or smaller to control the amount of light being taken in.

Answer 212

A

alter the shape of the cornea to focus on various distances onto the retina

Answer 213

A

are centrally located and focus on the use of colour. They require bright light.

Answer 214

A

are arranged around the cones and are extremely sensitive to light levels but not to colour, so they function better at low levels of light.

The eye adapts to light changes by adjusting the iris to change the diameter of the pupil and chemically changing in the light sensitive cells on the retina.

Answer 215

A

is a sensitive area on your retina. It is used for fine detail (threading a needle).

Answer 216

A

forms a blind spot in your eye.

Answer 217

A

30-40 minutes away from bright light to allow rhodopsin to reach max. Concentration.

Answer 218

A

vertigo is where bright light flickers as it passes through a propeller blade on a helicopter. This causes distraction to dizziness and disorientation.

Nothing for eye to focus on between cockpit and infinity, lens takes up a resting position [ciliary muscle relaxed]

Answer 219

A

Can be countered by occasionally looking at wingtips, nearby cloud tops or ground features if they become visible.

Answer 220

A

o Long sightedness
o Eyeball is too short or refractive power of lens is too weak.
o Condition corrected by convex lens.

Answer 221

A

o Short sightedness
o Eyeball is too long.
o Corrected by concave lens.

Answer 222

A

o Causes distortion of different parts of object to different degrees causing blurring of some parts
o Cylindrical lens
o Correction by cylindrical lens

Answer 223

A

o Natural ageing process, lens becomes less flexible
o Difficulty in focusing on nearby objects
o Interocular Lenses
o For some eye types allows subject availability of better sight without use of glasses for most flying operation

Answer 224

A

inertia causes fluid in the inner ear to flow backwards.
o Hair like cells send messages to the brain.
o Nerves and muscle joints send messages to the brain.
o Without absence of visual cues, brain is uncertain which of these has occurred.

Answer 225

A

tilted downwards.

o Fluid in the ears slosh forwards
o absence of visual stimulation, brain cannot distinguish between acceleration and deceleration.
o Don’t feel inertia roll so point correct position.
o The semicircular canals detect pitch, roll and yaw.
o Pilots restrict their head movements to as little as possible.

Answer 226

A

directly, instead, it reacts to changes in the carbon dioxide content of the blood

Answer 227

A

exertion so sends command to increase breathing rate.

o OK for surface dwellers, since need for extra oxygen is accompanied by rise in CO2 levels associated with hard physical work.
o Cannot be relied upon when we fly since a lack of oxygen at high altitude is not associated with physical exertion.

Answer 228

A

78% nitrogen, 20% oxygen, 2% other rare gases including CO2.

Answer 229

A

Ratio of component gases remains constant as altitude increases.

Answer 230

A

20% of that would be due to oxygen

o I.e. 202.6hPa, this is the partial pressure of oxygen
o At 36,900 the total pressure of the atmosphere would be 226hPa. 20% of that would be oxygen, so partial pressure of oxygen only 45.2hPa

Answer 231

A

upon partial pressure within the lungs.

Answer 232

A

, none would enter blood stream if pressure was too low.

Answer 233

A

90% saturated with oxygen, healthy person feels no noticeable effect.

Answer 234

A

partial pressure of oxygen drops to point where transfer of oxygen to blood stream is impaired

Answer 235

A

o At 33,700 feet, without cabin pressure, becomes necessary to breathe pure oxygen to maintain adequate blood saturation level.

Answer 236

A

pressurising the cabin to maintain a pressure equal to 8,000 feet, or by using an oxygen mask to increase % of oxygen in air being breathed. This increases the partial pressure of oxygen in the lungs.

Answer 237

A

pressurisation or supplemental oxygen, oxygen levels in blood begin to fall.

o But CO2 levels unchanged, so brain is unaware of oxygen crisis
o No feeling of suffocation because lungs can still be filled easily with low pressure air.
o While pilot feels comfortable, brain is starved of oxygen.

Answer 238

A

o Mild intoxication like alcohol
o Marked reduction in night vision

Answer 239

A

o Slowed thinking
o Impaired judgement
o Feeling of euphoria
o Impression performance is actually above average

Answer 240

A

o Erratic behaviour
o Unconsciousness
o No time will subject have any feeling of suffocation or become distressed
o Cyanosis - blue colouration of lips and fingernails

Answer 241

A

A few breaths of oxygen usually provide full recovery in a few seconds with subject reporting no memory of his/her actions while in hypoxic state.

Answer 242

A

20,000ft = 10 mins (mod activity); 20mins (quiet)
25,000ft = 3 mins (mod activity); 5 mins (quiet)
30,000ft = 1 min (mod activity); 3 mins (quiet)

Answer 243

A

10% haemoglobin occupied by CO

Answer 244

A

effectively up to 8000ft altitude before leaving the ground.

Answer 245

A

enhance effects of hypoxia.

Answer 246

A

air entry to lungs and subject may be relatively hypoxic on ground

Answer 247

A

o Poor oxygenation of blood

Answer 248

A

o Decrease in amount of haemoglobin available

Answer 249

A

high altitude

Answer 250

A

CO2 without increasing oxygen carried.

Answer 251

A

determinant of oxygen saturation of blood is pressure of oxygen in lungs, not volume that can be breathed in and out.

Answer 252

A

loss of consciousness

Answer 253

A

o Holding breath or voluntarily decreasing rate of breathing will help alleviate symptoms

o Breathing into paper bag held over nose and mouth causes exhaled breath to be rebreathed.

o Will rapidly increase CO2 level of blood

Answer 254

A

o Breath forcibly exhaled from lungs
o Sudden trop in cabin temperature
o Pain in stomach, ears and sinuses
o Turbulent wind as air escapes violently from cabin

Answer 255

A

no supplemental oxygen required
o By 10000ft, measurable degradation in night vision and some higher mental functions

Answer 256

A

continuous flow oxygen mask is adequate

o Simply allows oxygen to flow continuously into a storage bag attached to mask
o When user inhales, oxygen drawn from storage bag until deflates. Ambient air is inhaled to satisfy remaining capacity of lungs.
o Cheap and simple but relatively inefficient

Answer 257

A

demand oxygen mask used

o Equipped with a system of valves which allow more efficient control over oxygen flow.
o System supplies increasingly higher percentages of oxygen until from 33,700 ft to 40,000ft 100% oxygen is being inhaled.

Answer 258

A

pressure demand oxygen mask used

o Partial pressure of oxygen so low that even breathing 100% oxygen does not supply blood with sufficient oxygen
o This mask supplies 100% oxygen under increased pressure to the lungs

Answer 259

A

Euphoria
Cyanosis- (blue colouration of lips and fingernails)
Impaired mental ability
Unconsciousness

Administer oxygen
Descend to lower altitude

Answer 260

A

Tingling hands and feet
Breathlessness
Feeling of suffocation
Panic

Slow rate of breathing
Breathe into paper bag
Oxygen won’t help

Answer 261

A

Loss of concentration
Breathlessness
Nausea
Headache
Drowsiness
Unconsciousness

Administer oxygen
Remove source of CO
Ventilate cabin

Answer 262

A

o A short sense of euphoria
o Can act as a depressant
o False impression that performance is above average when in fact thinking is slowed and judgement impaired.

Answer 263

A

effects such as slurred speech, unsteadiness of feet
Loss of inhibitions are noticed by others, but not the intoxicated person

Answer 264

A

Only 10% of alcohol rids itself by breath, sweat and kidneys. Remainder is broken down by liver

Answer 265

A

1 standard drink per hour for man of average body weight less than half of this for an average woman

Answer 266

A

balance mechanisms of the inner ear destabilized

Answer 267

A

Reduction in the ability to process information has been evident

Answer 268

A

Should not consume more than one or two drinks within 24 hours of flying.

Answer 269

A

Max. Recommended alcohol intake over a period of one week is 21 to 28 standard drinks for a man and 14-21 standard drinks for a woman.

Answer 270

A

24 hours after heavy drinking.

Answer 271

A

acidity of the blood due to loss of carbon dioxide

Answer 272

A

18000 feet, atmospheric pressure is half of sea level

cavities in the middle of the ear and sinuses expand

Answer 273

A

: Pilots must abstain from alcohol for 8 hours before flight. Effects of alcohol can last beyond this period.

Answer 274

A

Avoid more than one or two drinks within 24 hours of flying. Weekly limits: 21-28 drinks for men, 14-21 for women.

Answer 275

A

General Effects: Both prescription and over-the-counter drugs can affect performance and behavior (e.g., drowsiness, dizziness).
Medical Advice: Consult a Designated Aviation Medical Examiner (DAME) before flying with any prescribed drugs.

Answer 276

A

Pain relievers such as aspirin (risk of bleeding), codeine (addictive, can test positive for opiates), and paracetamol (risk of liver damage). Consult a doctor for persistent pain.

Answer 277

A

Used for congestion from colds, flu, and sinus problems; cause drowsiness and degraded performance.

Answer 278

A

Found in nasal sprays; can be incompatible with other medications and cause damage with excessive use.

Answer 279

A

(Amphetamines & Caffeine): Illegal and legal forms (e.g., for ADHD) can cause restlessness, anxiety, and heart issues. Caffeine can cause sleeplessness and irregular heart rhythms.

Answer 280

A

Generally safe, but allergic reactions and side effects can occur. Avoid flying if on a new antibiotic.

Answer 281

A

Used for anxiety; cause drowsiness and dizziness, and can be habit-forming.

Answer 282

A

Used for sleep disorders; cause dizziness, blurred vision, and other side effects, and are habit-forming.

Answer 283

A

High or low blood pressure can disqualify pilots. Some medications are acceptable but require consultation with an aviation medical authority.

Answer 284

A

Prevention is Better Than Cure: Maintain a healthy diet and lifestyle to minimize medication needs.

Answer 285

A

Do Not Mix: Combined effects are greater than their individual effects.

Answer 286

A

Always consult with medical authorities if unsure about a condition or medication’s impact on flying abilities.

Answer 287

A

if someone goes SCUBA diving and flying straight after, the symptoms of decompression sickness can happen at heights as low as 8000 feet even if there was no problem with the dive.

Answer 288

A

High positive G causes higher heart rate
Triggered by the drop in oxygen level in the brain, however takes a few seconds for it to take full effect.

Answer 289

A

o Brain is able to cope due to residual oxygen which was present before the manoeuvre.

Very high G load over 5 seconds

o Residual oxygen is used up before the cardiovascular system can fully compensate by increasing heart rate. Resulting lack of oxygen causes grey out, black out and eventual [G-LOC]

Answer 290

A

o Fully conscious and capable of flying aircraft
o Low blood oxygen levels cause peripheral vision to fade
o Objects in centre of field of view can be seen but they appear to be surrounded by a grey haze.
o Will happen around 3.5G

Answer 291

A

o About 5G, grey haze envelopes entire field of view and almost immediately becomes black. Pilot is still conscious but cannot see.

Answer 292

A

o Follows very quickly if high G load is sustained.
o Pilot is unconscious and incapable of flying
o Consciousness is quickly regained when G load is released. [when pilot stops pulling back on the stick]

Answer 293

A

o Hypoglycaemia
o Diabetes
o Impairs heart’s ability to compensate at onset of high G-Loads
o Grey out and black out occur at relatively low sustained G loads.
o Heat stress caused by a hot cockpit environment can cause substantial decrease in G tolerance
o Hypoxia at high altitudes without oxygen causes blood oxygen level to be low even before the onset of any G load.
o Respiratory infection including common cold

Answer 294

A

o more reclined seating position brings heart more in line with the brain.
o Tensing stomach muscles
o Physical fitness
o Maintaining a good level of general fitness will assist in performance under high G

Answer 295

A

o Excess of blood in arteries leading to the head
o Heart responds by slowing down

Answer 296

A

o Sustained negative G can force the bottom eyelid over the eye ball causing field of view to turn red.
o Condition is called red out
o Safe limit for negative G is about -3G
o Immediate effect of negative G is rupturing of small blood vessels in face and eyes causing bloodshot eyes and red blotches on the face

Answer 297

A

o Sudden change from sustained negative G to high positive G greatly increases the chance of experiencing grey out or black out.
o Heart slows down under negative G, so when positive G is applied, it must change from slower than normal to faster than normal to compensate.
o Once positive G is applied, residual oxygen in brain is depleted before the heart can increase blood flow
o G threshold at which grey out or black out will occur will be much lower than normal.

Answer 298

A

CO is 3-9% in exhaust of piston engines
Gas turbine engines [about 0.003%]

engines

Answer 299

A

Very low levels, no symptoms
As saturation rises, there is an insidious, marginal impairment of performance, aggravated by exertion.
As saturation increases, first symptoms appear. Include slight headache, fatigue and mild discomfort in breathing.
At still higher levels impairment of vision, mental confusion [difficulty in performing relatively simple mental calculations], severe headache and sometimes vomiting
Very high concentrations result in unconsciousness and death.

Answer 300

A

o On dark nights no visual information once the aircraft becomes airborne and the runway lights are lost to view  acceleration can be mistaken for a steep climb and the pilot may respond by lowering the nose in an attempt to reduce the imagined climb angle. This causes the pilot to dip the dose to counter act and dive towards the ground due to the false sense of climbing.

Answer 301

A

o is when you view a distant light on a dark night and you perceive that object to be moving

Answer 302

A

o when focusing on a fixed object, everything in front of the object looks like It is moving away from you as you move your head
o All objects behind the object look like they are moving in the same direction as you.

Answer 303

A

o Clear air
o Over water or featureless terrain
o Narrow runway
o Total darkness, except runway lights
o Runway slops down to threshold
o Longer runway
o Light dimmer than usual
o Slops up to runway.

Answer 304

A

o Runway slopes up to (down from) threshold.
o Terrain slopes down to (up from) the threshold.
o Runway is wider-than usual.
o Runway is shorter than usual.
o Visibility is poor.
o Runway approach lights are dimmer than usual

Answer 305

A

o Doesn’t feel initial roll
o Feels correction
o Thinks aircraft is banking too far

Answer 306

A

o When the head is tilted forward, canal that was in yawing plane moves to the rolling plane
o Certain combinations of head movement, especially during a turn can create an unpleasant tumbling sensation which at best can be distracting, at worse almost incapacitating.

Answer 307

A

o Best to restrict the head movements to as little as possible
- When placed in a continuous gentle turn of about 15 degrees the inner ear reacts initially however if the turn is prolonged, the fluid of the inner ear regains equilibrium and the sensation of turning halts.

Answer 308

A

o When you attempt to fly within clouds and end up in a spiral due to your eyes disorientated from when you are feeling in your sense of balance (conflicting postural cues)

Answer 309

A

o The eye when a horizon is not available will seize upon another continues surface and assume that to be the horizon
o If that surface isn’t level then the brain goes against the artificial horizon as it appears that the slope is flat and the horizon over the actual horizon

Answer 310

A

o Our brains associate that light comes from above so when the clouds block part of the sun to make it appear elsewhere so when flying you can fall into a turn based off the illusion that the sun has to be above you

Answer 311

A

little use for distances of more than 1 metre, so depth perception for more distant objects must rely on other cues

Answer 312

A

o In clear air, brain can be fooled into thinking objects are closer than they actually are.
o Heavily polluted atmosphere or fog makes objects appear further away than they actually are
o Hence more rear end collisions occur in fog.

Answer 313

A

o Build up of water on windscreen acts like a lens that refracts light and makes the angle to the runway threshold appear steeper than it actually is
o Pilot may think he is overshooting when he is on correct approach path.

Answer 314

A

o The black-hole illusion occurs during nighttime approaches over featureless or dark terrain, where only runway lights are visible or bright city lights are behind the runway (no lights on final).
o This lack of visual cues can cause pilots to lose depth perception, making the runway lights appear as though they are painted on the windscreen.
o Key effects include:
 Undershoot Risk: Pilots may falsely believe they are too high and tend to undershoot the runway.

Answer 315

A

Supercharges are implemented to compress air to give to the engine as when you increase altitude the air gets thinner
Engine needs oxygen to complete combustion
Driven by engine

Answer 316

A

Are more efficient than superchargers
Turbochargers solve the thin air problem in piston-driven engines by compressing intake air before it reaches the cylinder
Utilise kinetic energy from exhaust gases to drive turbine which is connected to the centrifugal compressor

Answer 317

A

Not all gases are used to drive turbine at low altitudes otherwise the pressure achieved would be to high for the engine
This is accommodated by the waste gate allowing any amount of waste gas to flow through without spinning turbine

Answer 318

A

As you compress air, it heats up. This is one of the biggest disadvantages of any turbocharger.

Answer 319

A

o The slipstream from the propeller spirals back around the fuselage such that it impacts the fin and rudder from the left side.
o This pushes the tail to the right causing the nose to yaw to the left.
o Right rudder is required.

Answer 320

A

o Newton’s Third Law
o The torque reaction of the propeller in the opposite direction to its rotation.
o The propeller attempts to rotate the aircraft in the opposite direction of its rotation (so anticlockwise)
o This causes more load to be placed on the left wheel, causing a braking effect on the left wheel.
o Result is that the nose yaws to the left during take-off run
o Right rudder is required to counteract this effect.

Answer 321

A

o A rotating propeller acts similarly to a gyroscope
o When a gyroscope rotates, a force acts 90o further in the direction of the rotation.
o 90o later in the direction of rotation is to the right side of the propeller, causing the aircraft to yaw to the left.
o Right rudder is required to counteract this effect

Answer 322

A

o The down going blade of the propeller strikes the airflow at a greater angle of attack than the upgoing blade
o The down going blade travels further than the upgoing blade therefore travels faster through the air.
o The overall effect is that the right half of the propeller disc (viewed from the cockpit) produces more thrust than the left half and causes the aircraft to yaw to the left.
o As a result, there is a need to apply right rudder during take -off when the aircraft is fitted with a clockwise turning propeller.

Answer 323

A

A propeller that doesn’t change its angle of attack and remains at a fixed pitch angle
This is set for best efficiency at cruise speed

Answer 324

A

This allows for the pitch of the propeller to be adjusted to different pitches such as:
o Fine pitch: small angle of attack. Bites of less air causing higher RPM
o Coarse pitch: large angle of attack. Bites of more air causing slower RPM
o Feathered: blades have no angle of attack. Highest RPM speed

Answer 325

A

This is controlled through a governor which sets the RPM to keep it on speed (speed that pilot sets)
The governor works through oil flowing through the nose changing the pitch
Throttle will not change RPM in a variable pitch propeller

Answer 326

A

A decrease in throttle, indicated by reduction in manifold pressure, will cause an UNDER-SPEED condition on the variable pitch propeller. The governor automatically FINES the propeller pitch angle to maintain the same RPM.

Answer 327

A

The throttle setting is now monitored by the manifold pressure gauge.
During flight, an increase in throttle, indicated by increased manifold pressure, will initially cause an OVER-SPEED condition on the variable pitch propeller. The governor automatically COARSES the propeller pitch to absorb this extra power and to maintain the same RPM.

Answer 328

A

When increasing performance go (MRT) mixture, RPM and throttle
When decreasing performance go (TRM) throttle, RPM and mixture

Answer 329

A

Traveling as far in distance as possible
This is achieved by
o Flying at a height which requires full throttle to just supply the required power
o Operating at max lift/drag ratio

Answer 330

A

To fly for as long as possible
This is achieved by
o Flying low as possible. This is so that the denser the air the lower the power required
o Minimum power for level flight

Answer 331

A

flyweights remain where set not allowing oil to change to keep pitch constant.

Answer 332

A

If pilot pulls up the RPM will momentarily decrease so the fly weights in the governor will fall towards the centre to allow oil to drain from nose to reduce pitch (fine pitch) to allow RPM to catch up. Then the fly weights will rise back to where it was set and RPM remains at set.

Answer 333

A

If pilot pushes forward the RPM will momentarily increase so the fly weights in the governor will fall outwards from the centre to allow oil to fill the nose to increase pitch (coarser pitch) to allow RPM to fall down. Then the fly weights fall back to where it was set and RPM remains at set.

Answer 334

A

VSO-Stalling speed - bottom of white arc (flaps down)
- VS1: Stalling speed - bottom of green arc (flaps up)
- VFE: Maximum flap extension speed - top of the white arc
- VFO: Flap operating speed - white arc
- VNO: Normal operating speeds - green arc
- VNE: Never exceed speed - red line.
- VX: Maximum angle of climb (54knts in a 152)
- VY: Maximum rate of climb (65knts in a 152
- Vz: normal climb (75knts in a 152)
- VB: Turbulent Penetration speed - speed flown in turbulent weather.
- VA:Manoeuvring speed - maximum speed at which full deflection of control surfaces is allowed

Answer 335

A

at full deflection elevators, the plane will stall before you get to a load that will damage the aircraft.

Answer 336

A

to a critical load factor (more than the plane can handle) before the plane stalls, so you will likely damage the aircraft or die

Answer 337

A

turbo jets work through intaking air, compressing it, combust it, then release it at a high speed
Some of the air bypasses the combustion chambers and provides the necessary cooling to the engine as well as thrust out the back

Answer 338

A

Compresors are used to compress the air to a higher density so when expelled out the back if the aircraft at high speeds it provides more thrust
There are 2 types of compressors:

Answer 339

A

can be wither single or in two stages. As air enters the fan it is forced to the outside due to the centrifugal force and pushed through small gapes where it compresses.

Answer 340

A

is where the compressor directs air longitudinally or axially through a number of stages of rotating rotors and stationary stators

Answer 341

A

Combustion chambers are designed to have only 25% of airflow used for combustion
The rest of the air enters the combustion chamber through holes in the latter half of the casing. This acts to cool the casing and cool the exast gas temperature.

Answer 342

A

which has individual chambers arranged around the engine.

Answer 343

A

combustion chamber fit inside a common casing (one big combustion chamber).

Answer 344

A

The turbines function is to drive the compressor. It does this through converting energy from exhaust gas stream into energy. Work in a number of stages.

Answer 345

A

If the pressure created by the ignition of the fuel and air exceeds the pressure in the compression chamber, some of the exhaust may actually be pushed forward and exit the front of the engine. This is a compressor stall. NO OXYGEN THROUGH SYSTEM

Answer 346

A

Cool air: When heated, cool air expands more than warm air. Hence, the larger the expansion of the air when heated, the faster the aircraft moves because it is the expansion of air that drives the turbines of the jet engine which generates more power for lesser fuel burn.
Less drag: at high altitude, there is low drag because the density of air is now lower than it was at a lower altitude.
Improved thermal efficency: The cold air at this altitude improves the thermal efficiency of the engine because less work is done to compress the incoming air (cold air more dense than hot air).

Answer 347

A

o Able to produce great amounts of power at high altitudes and high speeds
o Efficiency of jet engines increases with altitude and speed
o Reliability as has less moving parts than a piston engine.
o Longer range thanks to faster cruising speed and ability to fly at higher altitudes. Makes the aircraft best suited for mid-longer range flights.
o Although external noise is significant, cabin noise in a jet aircraft is much more reduced than in a propeller aircraft

Answer 348

A

o Thermal efficiency is lower, particularly at low altitude and speeds less than 300 knots.
o The fuel consumption is 2-3 times that of a piston engine in these conditions
o The engines are considerably more noisy than piston engines
o Materials to produce the parts of the jet engine are costly and require frequent replacing or maintenance.
o Require longer, concrete runways.
o Less efficient and less cost effective for shorter distances.

Answer 349

A

o Although Jet engines are relatively quiet when inside the cabin of the aircraft, they are externally very noisy and most large cities have a curfew on times large aircraft can land and take-off from airports close to them.
o The combustion of hydrocarbon fuels high in the upper atmosphere are believed to contribute to climate change by depositing carbon dioxide. Aviation emissions have increased substantially since 2005 and could grow by 300% by 2050.
o High performance and military aircraft that travel at supersonic speeds create sonic booms which can cause damage to built up areas.

Answer 350

A

o Although the operating principles are quite simple, jet engines and their associated parts are expensive due to specialised manufacturing and materials used in their construction.
o Maintenance must be performed often and consistently on jet engines to keep them operating safely and efficiently. This is often very costly as is very specialised.

Answer 351

A

The turboprop engine is a gas turbine engine that uses an additional POWER TURBINE to turn a propeller via a speed reduction gearbox.

Answer 352

A

Unlike a turbojet, it can produce considerable thrust during take-off and is well suited to shorter runways and lower altitudes than gas turbine engines.
This means that after the engine has been started it can operate at almost constant RPM, despite changes which the pilot might make to the RPM of the propeller in flight.

Answer 353

A

Is more lightweight than a turbojet, giving better performance at slower speeds and lower altitudes
Able to take off and land on shorter and non-concrete runways whereas jet engines need a long take off run and require smooth, flat surfaces
Lower operation costs from lower maintenance costs as turboprops are generally more reliable than traditional turbojet engines

Answer 354

A

Slower cruising speed means longer flight times. Any propeller loses efficiency over 300 knots.
Lower cruising altitudes of around 25000-30000 feet mean that susceptible to weather conditions at this altitude. Jet engines are able to fly at much higher altitudes which avoids most turbulent weather.
The slower cruising speed and lower cruising altitudes equates to a shorter range even when factoring in improved efficiency. Great for short and mid-range flights, but not designed for long distance travel.

Answer 355

A

If the free turbine is used to drive something other than a propeller then it is called a turboshaft engine. Most helicopters are driven by turboshaft engines.

Answer 356

A

Advantages
- Simplicity of control.
- Negligible cooling air required.
- No spark plugs required except for starting – once combustion is established, it is self-supporting.
- Decreased fire hazard, less volatile fuels are used.
- Lower specific weight.
- Lower oil consumption.

Answer 357

A

Disadvantages
- High specific fuel consumption at low air speeds – applies chiefly to pure jet engines have performance comparable to reciprocating engines.
- Inefficient operation at low power levels
- Slow acceleration from minimum to maximum power level – this condition applies chiefly to turbojet engines. Turboprop and turbofan engines are able to accelerate quite rapidly.
- High starting power requirements.
- High-cost manufacture.

Answer 358

A

Is similar to the turboprop exept that a large axial flow ducted fan is substituted for the propeller
Ratio between airflow through the fan and the airflow through the gas generator is known as the bypass ratio
Higher the bypass ratio the quieter the engines are

Answer 359

A

Thermodynamic efficiency is the measure of heat that the engine produces that is transformed into work. Turbofan engines have a higher thermal efficiency than turbojet engines.
Bypass air allows improved acceleration for take-off compared to normal turbojet engines.
Allows better performance at lower speeds than turbojets
Reduced fuel consumption compared to turbojets due to the presence of the large fan which creates much of the thrust force.

Answer 360

A

Cannot handle sudden fluctuating load.
Expensive to maintain and operate with very specialised parts compared to a simple turbojet

Answer 361

A

Being able to separate high and low pressure turbines means that the different sized compressors and fan at the front of the engine can be rotated at their optimal speeds.
The optimal rotational speed of a compressor or fan is determined by the relative speed of the blade tip to the speed of sound.
A large blade will be optimised at a slower rotational speed than a smaller blade, hence matching a fast spinning turbine to a large fan will mean one of them is not running efficiently

Answer 362

A

. In this case, usually the turbine speed is dictated by the fan speed, hence the turbine will be spinning to slowly to be efficient.
- Most engine manufacturers employ a 2-spool design, as shown in the diagram to the side, where a fan and/or low-pressure compressor is driven by a low-pressure turbine, with a high-pressure compressor driven by a high-pressure turbine.

Answer 363

A

Difference between a 2 pool and a 3 spool engine is that a 2 spool engine has a fan followed by a high power compressor whereas 3 spool engine is the fan into an intermediate compressor followed by a high powered compressor
Engine manufacturers typically limit the rotation speed of the shaft powering the fan to the optimal fan blade tip speed, which causes the low-pressure compressor and turbine to rotate much slower than optimal

Answer 364

A

A thrust reversal is used to slow down the aircrafts speed by redirecting air in the opposite direction
There are different types:

Answer 365

A

When activated, Internal and external doors divert cold thrust from secondary airflow in the reverse direction to forward thrust

Answer 366

A

where the air is blocked by a clam shell that propels the air in the opposite direction to the engine

Answer 367

A

Throttle effects manifold pressure
Mixture controls EGT
Pitch controls RPM

Answer 368

A

A turbojet engine is the simplest form of a gas turbine engine. It compresses air, mixes it with fuel, ignites the mixture, and expels the exhaust gases out the back, producing thrust.

Answer 369

A

A turbofan engine is a more advanced version of the turbojet, with a large fan at the front. The fan pushes a large volume of air around the outside of the engine core, creating additional thrust and improving efficiency.

Answer 370

A

A turboprop engine uses a gas turbine to drive a propeller. The turbine generates thrust by turning the propeller, which pushes air backward to propel the aircraft forward.

Answer 371

A

A turboshaft engine is similar to a turboprop but is designed to drive a shaft rather than a propeller. It is commonly used in helicopters.

Answer 372

A

Reducing the horizontal visibility at the earths surface to less than 1000 meters
The 3 processes which can lead to water vapour saturation are:
o The introduction of a layer of moist air into cold air near the earth’s surface
o The addition of water to the atmosphere by evaporation
o Cooling of moist air either through its ascent up a slope or by contact with a cool ground or sea surface.

Answer 373

A

o visibility challenges when flying with fog present.
o Dangers of fog for an aircraft on approach to an airport

Answer 374

A

forms over land during the evening or early morning and develops as a result of the earth losing its heat by radiation into space. The air in contact with the surface loses its heat to the ground by conduction and its temperature drops. When its dewpoint temperature is reached, water vapour in the air will form into cloud droplets, or fog.

Answer 375

A

o light winds (usually less than 4 knots);
o cloudless skies - which permits the ground to radiate its heat into space;
o high relative humidity - usually following a period of rain;
o presence of condensation nuclei, such as dust and minute particles of pollution.

Answer 376

A

An inversion (increase in temperature with altitude) accompanies radiation fog because the air near the surface of the earth is being cooled from below.

Answer 377

A

that when looking from above fog you can see the runway due to the shorter distance, but when on approach you are looking at a longer distance in fog so harder to see runway.

Answer 378

A

The horizontal passage of moist air over any cold surface may result in formation of advection fog.

Fog can only occur if the temperature of the moist air is reduced to its dewpoint temperature.
This type of fog is often experienced along coastal regions in winter.
May develop during either day or night and forms when a warm, moist air mass is cooled rapidly as it flows over a cold land mass.
Happens during winter when warm moist air flows over a cool land mass to cool.

Answer 379

A

Smoke is the visible product of incomplete combustion
Problems for pilots and aircraft:
o Obvious visibility problems
o Not being able to see the ground
o Inadvertently flying through smoke could cause airborne particles to clog vents and air systems, causing engine failure

Answer 380

A

reduced below 1000 metres, the phenomenon is referred to as a dust storm or as a sandstorm.

When the resultant horizontal visibility is reduced below 1000 metres, the phenomenon is referred to as a dust storm or as a sandstorm.
The necessary conditions for a dust storm include a dry and dusty land surface, moderate wind speeds to lift and transport the dust and an unstable atmosphere to promote vertical movement.

Answer 381

A

widespread and can exist for several days, reducing visibility to less than 100 metres.
- The difference between a dust storm and a sand storm is the size of the particles.
- A dust storm consists of fine particles, often raised to great heights (3000 metres), which may be carried great distances from the source.
- A sandstorm consists of coarse particles, which are not usually raised to a great height or carried far from the source.

Answer 382

A

o Visibility issues
o Very turbulent wind conditions inside a dust or sandstorm

Answer 383

A

Turbulence describes the air which is eddying or swirling.
When aircraft encounter turbulence, their passage may include uncontrolled vertical and horizontal movements.
It is of concern to aviators because of the effect it has on their ability to control the aeroplane and the physical discomfort which it causes to the occupants of the aircraft.

Answer 384

A

o thermal turbulence
o mechanical turbulence
o clear-air turbulence (CAT).

Answer 385

A

thermal turbulence results from convection currents set up by surface heating. It also occurs when a relative cool mass of air passes over a warmer land or sea surface.
In convective clouds, especially thunderstorms, latent heat is released at cloud height and this energy causes updraughts and downdraughts, representing large eddy-type motions. These in turn give rise to numerous smaller turbulent addies of various magnitudes.

Answer 386

A

Mechanical turbulence, also referred to as frictional turbulence, is usually experienced within the lower layers of the atmosphere. The intensity of these eddies and hence turbulence, is primarily dependent upon the size of the obstruction and the speed of the surface wind.

Answer 387

A

Clear-air-turbulence (CAT) is defined as turbulence of a type other than that associated with airflow close to rough terrain or that encountered in or near convective clouds.
Clear-air-turbulence has been observed mainly in the high troposphere and low stratosphere especially in the vicinity of jet streams which are relatively small ‘bands’ of strong wind.
Its chief practical significance lies in the acceleration, varying in intensity up to several ‘g’, which it may impart to aircraft as they fly through it.

Answer 388

A

and to the lee of mountain ranges in the south-east of the continent.
- Mountain waves are defined as ‘severe’ when the associated downdrafts exceed 600 ft/min and/or severe turbulence is observed or forecast.

Answer 389

A

o the wind flow at around ridge height is nearly perpendicular to the ridge line and at least 25 kts
o the wind speed increases with height
o there is a stable layer at around ridge height.

Answer 390

A

(the ragged clouds below the lenticular clouds in the figures below), that indicates extremely violent turbulence with up and downward motions that can exceed the climb speed of the aircraft. If the rotor is near the ground near an airport, then pilots should avoid that airport and land somewhere else.

Answer 391

A

Thunderstorms are only associated with cumulonimbus (Cb) clouds. Phenomena associated with thunderstorms include:

o severe turbulence
o moderate to severe hail
o heavy to very heavy rain
o squalls
o micro-bursts
o tornadoes.

Answer 392

A

o a cumulonimbus cloud in which the temperature falls below freezing level
o the occurrence of precipitation
o an adequate supply of moisture
o an unstable atmosphere with a lapse rate in excess of the SALR through a range of not less than 3000 meters above the cloud base
o an initial trigger - often provided by orographic uplift or by horizontal convergence of surface air (along troughs, fronts).

Answer 393

A

Formed along the surface position of a front as the warm air rides up over the denser cold air

Answer 394

A

Formed in a cold airstream which moves rapidly into warmer latitudes. This is from south to north in the southern hemisphere. Latitudinal heating of the surface layers does not depend on direct solar heating, so it continues day and night. The lightning from these storms can sometimes be seen over the ocean through the night.

Answer 395

A

Formed when air is lifted by its passage over a mountain range. This effect is often combined with convection, causing storms which have formed in the afternoon to become more frequent and persist longer in the vicinity of mountain ranges.

Answer 396

A

. Triggered along a well formed trough of low pressure. As the surface air veers across the isobars towards the lowest pressure, the air along the trough lines folds back on itself. This convergence forces the air at the surface to rise.

Answer 397

A

Formed when initial lifting is caused by solar heating of the surface. These typically begin forming in the mid afternoon during the summer months

Answer 398

A

The life cycle of a thunderstorm can be divided into three stages, based on the speed and direction of the vertical currents.

Answer 399

A

 All air movement is upward within the cloud
 Edges and tops grow rapidly
 Large water droplets and snowflakes are suspended in strong updrafts
 No precipitation yet but virga may be present

Answer 400

A

 Begins when water droplets or ice particles (hail) become too heavy to be supported by updraughts and fall from the base of cloud
 Frictional drag exerted by precipitation assists to change updraught into downdraught in some parts of the cell. Updraughts continue and reach maximum intensity in the upper regions of the cloud in early mature stage.
 Downdraught is most pronounced in lower portions of the cloud. The descending air is forced to spread out laterally near the Earth’s surface.

Answer 401

A

 Updraughts disappear completely
 Downdraughts spread out over the entire cell and condensation can no longer occur. Once the supply of falling rain and hail ceases, the downdraught weakens.
 Dissipation is complete when temperature within the cell is restored to approximately that of the environment.
 At surface all signs of thunderstorm and downdraughts have disappeared.
 Top of cloud appears more fibrous.

Answer 402

A

The term microburst is often associated with cumulonimbus cloud. In essence, it is powerful downdraughts of air in which large fluctuations in wind speed and direction are often encountered by aircraft which are traversing the cloud base.

Answer 403

A

o The aircraft is on approach to land. It is experiencing a headwind from the strong downdraft created by the microburst.
o Directly underneath the microburst core, the headwind disappears and is now a force of wind directly downward. Wind shear will be experienced.
o On the other side of the microburst, the aircraft now experiences a tailwind which will affect airspeed.
o As the aircraft travels away from the microburst core, the tailwind increases, which decreases the speed of relative airflow over the wings which results in loss of lift and eventually a stall.
o Because the aircraft is so low to the ground, the results are often catastrophic.

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