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PPL Course - (3) Navigation and Meteorology > Chapter 8.6 - Hazardous Weather > Flashcards

Chapter 8.6 - Hazardous Weather Flashcards

1
Q

Name the four main types of hazardous weather which affecting flying?

A
  • Reduced Visibility.
  • Turbulence.
  • Thunderstorm.
  • Icing.
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2
Q

Define Prevailing Visibility?

A

Measurement of the greatest distance visible.

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3
Q

Visibility is a measure of the transparency of the atmosphere affect by which five meteorological factors?

A
  • Fog/Mist.
  • Precipitation.
  • Smoke.
  • Haze.
  • Dust.
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4
Q

The horizontal visibility is what in Fog?

A

Reduced to 1000m or less.

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5
Q

The horizontal visibility is what in Mist?

A

Above 1000m.

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6
Q

Name two types of Fog?

A
  • Radiation.

- Advection.

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7
Q

How does Radiation Fog occur?

A

Radiation fog forms as the land cools at night

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8
Q

How does Advection Fog occur?

A

Advection fog forms from warm, moist air moving over a cold surface.

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9
Q

Name two ways Fog dissipates?

A
  • Increased Windspeed.

- Warming.

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10
Q

Duststorms general reduce visibility to below how many metres?

A

1000.

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11
Q

Severe Duststorms can reduce visibility to below how many metres?

A

200.

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12
Q

Haze will be worst when significant concentrations of pollutants are trapped below an inversion associated with (cyclone/anticyclone)?

A

Anticyclone.

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13
Q

Define Turbulence?

A

Irregular motion of the atmosphere in both vertical and horizontal direction.

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14
Q

Turbulence that momentarily causes slight, erratic changes in Altitude and/or Attitude is reported as what?

A

Light Turbulence.

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15
Q

Turbulence that causes greater changes in Altitude and/or Attitude, as well as variations in indicated Airspeed is reported as what?

A

Moderate Turbulence.

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16
Q

Turbulence which causes large, abrupt changes in Altitude and/or Attitude, which may cause the Aircraft to be momentarily out of control is reported as what?

A

Severe Turbulence.

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17
Q

Turbulence which causes the aircraft to be violently tossed about and impossible to control is reported as what?

A

Extreme Turbulence.

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18
Q

Turbulence without changes in Altitude and/or Attitude is known as what?

A

Chop.

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19
Q

Name four types of Turbulence?

A
  • Mechanical.
  • Wake.
  • Thermal.
  • Low-Level Windshear.
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20
Q

What causes Mechanical Turbulence?

A

Wind blowing over obstructions such as irregular terrain, buildings and mountains.

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21
Q

What causes Wake Turbulence?

A

The production of lift by medium/large Aircrafts.

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22
Q

What causes Thermal Turbulence?

A

Temperature effects and interaction of different air-masses.

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23
Q

What causes low-level Windshear?

A

Abrupt wind strength and/or direction at low levels.

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24
Q

Name one major reason why Mountain/Standing Wave Turbulence can be extremely dangerous?

A

The Turbulence has no visible warning.

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25
Q

Turbulence associated with which type of front is more severe than the other?

A

Cold Front.

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26
Q

What is the general height of low-level Windshear?

A

Surface to 3000 feet.

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27
Q

Which component of the wind is Windshear affecting?

A

Horizontal.

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28
Q

When Windshear involves only a change of speed with changing height it is often called what?

A

Wind Gradient.

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29
Q

Define Shallow Wind Gradient?

A

The windspeed changes slowly/small amounts.

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30
Q

Define Steep Wind Gradient?

A

The windspeed changes quickly/large amounts.

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31
Q

Define Overshoot Shear?

A

Windshear which overshoots the approach path and/or increasing airspeed.

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32
Q

Define Undershoot Shear?

A

Windshear which undershoots the approach path and/or decreasing airspeed.

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33
Q

Overshoot Shear is also known as what in terms of wind (2)?

A
  • Increasing Headwind Shear.

- Decreasing Tailwind Shear.

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34
Q

Undershoot Shear is also known as what in terms of wind (2)?

A
  • Decreasing Headwind Shear.

- Increasing Tailwind Shear.

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35
Q

On Takeoff what effect will Overshoot Shear have on an Aircraft (2)?

A
  • Increase in Airspeed.

- Increase in Rate of Climb.

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36
Q

On Approach what effect will Overshoot Shear have on an Aircraft (2)?

A
  • Increasing Airspeed.

- Decrease Rate of Descent.

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37
Q

On Takeoff what effect will Undershoot Shear have on an Aircraft (2)?

A
  • Decrease in Airspeed.

- Decrease in Rate of Climb.

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38
Q

On Approach what effect will Undershoot Shear have on an Aircraft (2)?

A
  • Decreasing Airspeed.

- Increasing Rate of Descent.

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39
Q

Windshear which causes minor variation on an Aircraft’s flight path and/or Airspeed is known as what?

A

Light Windshear.

40
Q

Windshear which has a significant effect on the Aircraft control is known as what?

A

Moderate Windshear.

41
Q

Windshear which causes a high degree of difficulty in keeping an Aircraft’s flight path and/or Airspeed is known as what?

A

Strong Windshear.

42
Q

Windshear which has hazardous effects on an Aircraft’s controls or rapid changes in wind direction/speed is known as what?

A

Severe Windshear.

43
Q

The Turbulence Penetration Speed for Light Training Aircraft is describe as what?

A

Between 40%-60% above the Clean Stall Speed.

44
Q

Name two types of Icing that affects an Aircraft?

A
  • Structural Icing.

- Induction Icing.

45
Q

What happens to the aerodynamic characteristics of the Aircraft when ice forms?

A

Lift is reduced with the Stall Speed and Drag increasing.

46
Q

Name three factors which Icing has on Aircraft in flight?

A
  • Increase in Weight.
  • Increase in Stall Speed.
  • Loss of Lift.
47
Q

Name three factors which determine the rate of Ice accumulation?

A
  • Water.
  • Temperature.
  • Size of Liquid Drops.
48
Q

What is the Droplet Size for Clear Ice?

A

Large.

49
Q

At what temperatures will Clear Ice form?

A

0°C – 10°C.

50
Q

Name three hazards of Clear Ice?

A
  • Rapid Build-up.
  • Possible Loss of Control.
  • Difficulty in Removing the Ice.
51
Q

What is the Droplet Size for Rime Ice?

A

Small.

52
Q

At what temperatures will Rime Ice form?

A

0°C – 20°C.

53
Q

Name two hazards of Rime Ice?

A
  • Loss of Aerodynamic Efficiency.

- Possible Loss of Control.

54
Q

What is the Droplet Size for Mixed Ice?

A

Medium.

55
Q

At what temperatures will Mixed Ice form?

A

0°C – 15°C.

56
Q

How does Frost affecting flying (2)?

A
  • Disrupt the Aerodynamic Efficiency.

- Reduce Visibility.

57
Q

Airframe Icing decreases what (2)?

A
  • Lift.

- Thrust.

58
Q

Airframe Icing increases what (3)?

A
  • Drag.
  • Weight.
  • Stall Speed.
59
Q

True or False. 10mm of icing can reduce the lifting capabilities of up to 50%?

A

True.

60
Q

How long does it take for 10mm of Icing to occur on the airframe in severe icing conditions?

A

1-2 minutes.

61
Q

What two actions can a Pilot do to avoid Airframe Icing in Stratiform Clouds?

A
  • Descend to a level where Temperature is above 0°C.

- Climb to a level where Temperature is below 20°C.

62
Q

What action should a Pilot not do to avoid Airframe Icing in Cumuliform Clouds?

A

Do not climb.

63
Q

If a Pilot can’t descend out of a Cumuliform Cloud due to low cloud base, what course of action should be taken to avoid Airframe Icing?

A

Clear the cloud by turning 180°C.

64
Q

What three factors are required for Cumulonimbus Clouds to produce Thunderstorms?

A
  • Unstable Atmosphere.
  • Sufficient Water Vapour.
  • Trigger Action (Type of Thunderstorm).
65
Q

True or False. All Cumulonimbus Clouds produce Thunderstorms?

A

False.

66
Q

Name three types of Thunderstorms?

A
  • Frontal.
  • Air-mass.
  • Orographic.
67
Q

How are Frontal Thunderstorms formed?

A

Interaction of two air-masses (cold displacing warm air) at the frontal boundary.

68
Q

True or False. Air-mass Thunderstorms are associated with a Front?

A

False. They are generally isolated.

69
Q

Name three types of Air-mass Thunderstorms?

A
  • Heat.
  • Cold-stream.
  • Convergence.
70
Q

How are Heat Thunderstorms formed?

A

Through Convection by the heating from the ground.

71
Q

How are Cold-stream Thunderstorms formed?

A

When moist air is heated from below and becomes unstable.

72
Q

How are Convergence Thunderstorms formed?

A

When moist air is forced to raise

73
Q

How are Orographic Thunderstorms formed?

A

When wind forces moist, unstable air to rise over high ground.

74
Q

Name three stages of a Thunderstorm?

A
  • Cumulus.
  • Mature.
  • Dissipating.
75
Q

Cumulus Stage of Thunderstorm is dominated by what?

A

Strong Updrafts.

76
Q

How long does a Cumulus Stage last for?

A

15 minutes.

77
Q

Mature Stage of Thunderstorm is dominated by what?

A

Strong Updrafts and Downdrafts.

78
Q

How long does a Mature Stage last for?

A

20 minutes.

79
Q

Dissipating Stage of a Thunderstorm is dominated by what?

A

Strong Downdrafts.

80
Q

How long does a Dissipating Stage last for?

A

30 minutes to 1 hours and 30 minutes.

81
Q

Name four Thunderstorm Hazards?

A
  • Turbulence.
  • Hail.
  • Icing.
  • Lightening.
82
Q

Where does the worst Turbulence occur in a storm?

A

Middle and Upper Levels.

83
Q

True or False. Turbulence doesn’t exist several thousands of feet above and laterally of a storm?

A

False. It does.

84
Q

How can a Pilot tell the magnitude of Turbulence on the bottom leading edge of a storm?

A

By the roll of clouds.

85
Q

Other than Turbulence, what is the second worst thunderstorm hazard?

A

Hail.

86
Q

Where does Hail often appear to fall?

A

The overhanging ‘anvil’ of the storm.

87
Q

Where is the best path to avoid the Hail from a Thunderstorm?

A

Upwind of the cloud.

88
Q

How can Lightning affect the stand-by magnetic compass?

A

Induce permanent errors.

89
Q

A Pilot should avoid severe storms by at least how many miles?

A

20.

90
Q

Name two types of Downbursts?

A
  • Microbursts.

- Macrobursts.

91
Q

What are the three main characteristics of a Microburst (Length, Wind Speed and Duration)?

A
  • 50m to 1km in diameter.
  • Wind Strength up to 150 knots.
  • Duration between 10-20 minutes.
92
Q

Name three types of weather conditions where Microbursts can occur?

A
  • Thunderstorms.
  • Rain Showers.
  • Virga.
93
Q

What dangers can Microbursts have on an Aircraft?

A

Low-level Windshear.

94
Q

The initial outcome of a Microburst will always be an (increase/decrease) in Airspeed caused by the (increase/decrease) in Headwind?

A
  • Increase.

- Increase.

95
Q

What’s the main difference between an Aircraft entering a symmetrical and an asymmetrical Microburst?

A

Conditions in Headwind and Tailwind.

PPL Course - (3) Navigation and Meteorology (23 decks)

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