Chapter 8.6 - Hazardous Weather

Question 1

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

Answer 1

• Reduced Visibility.
• Turbulence.
• Thunderstorm.
• Icing.

Question 2

Define Prevailing Visibility?

Answer 2

Measurement of the greatest distance visible.

Question 3

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

Answer 3

• Fog/Mist.
• Precipitation.
• Smoke.
• Haze.
• Dust.

Question 4

The horizontal visibility is what in Fog?

Answer 4

Reduced to 1000m or less.

Question 5

The horizontal visibility is what in Mist?

Answer 5

Above 1000m.

Question 6

Name two types of Fog?

Answer 6

• Radiation.

- Advection.

Question 7

How does Radiation Fog occur?

Answer 7

Radiation fog forms as the land cools at night

Question 8

How does Advection Fog occur?

Answer 8

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

Question 9

Name two ways Fog dissipates?

Answer 9

• Increased Windspeed.

- Warming.

Question 10

Duststorms general reduce visibility to below how many metres?

Answer 10

1000.

Question 11

Severe Duststorms can reduce visibility to below how many metres?

Answer 11

200.

Question 12

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

Answer 12

Anticyclone.

Question 13

Define Turbulence?

Answer 13

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

Question 14

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

Answer 14

Light Turbulence.

Question 15

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

Answer 15

Moderate Turbulence.

Question 16

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?

Answer 16

Severe Turbulence.

Question 17

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

Answer 17

Extreme Turbulence.

Question 18

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

Answer 18

Chop.

Question 19

Name four types of Turbulence?

Answer 19

• Mechanical.
• Wake.
• Thermal.
• Low-Level Windshear.

Question 20

What causes Mechanical Turbulence?

Answer 20

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

Question 21

What causes Wake Turbulence?

Answer 21

The production of lift by medium/large Aircrafts.

Question 22

What causes Thermal Turbulence?

Answer 22

Temperature effects and interaction of different air-masses.

Question 23

What causes low-level Windshear?

Answer 23

Abrupt wind strength and/or direction at low levels.

Question 24

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

Answer 24

The Turbulence has no visible warning.

Question 25

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

Answer 25

Cold Front.

Question 26

What is the general height of low-level Windshear?

Answer 26

Surface to 3000 feet.

Question 27

Which component of the wind is Windshear affecting?

Answer 27

Horizontal.

Question 28

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

Answer 28

Wind Gradient.

Question 29

Define Shallow Wind Gradient?

Answer 29

The windspeed changes slowly/small amounts.

Question 30

Define Steep Wind Gradient?

Answer 30

The windspeed changes quickly/large amounts.

Question 31

Define Overshoot Shear?

Answer 31

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

Question 32

Define Undershoot Shear?

Answer 32

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

Question 33

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

Answer 33

- Increasing Headwind Shear. | - Decreasing Tailwind Shear.

Question 34

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

Answer 34

- Decreasing Headwind Shear. | - Increasing Tailwind Shear.

Question 35

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

Answer 35

- Increase in Airspeed. | - Increase in Rate of Climb.

Question 36

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

Answer 36

- Increasing Airspeed. | - Decrease Rate of Descent.

Question 37

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

Answer 37

- Decrease in Airspeed. | - Decrease in Rate of Climb.

Question 38

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

Answer 38

- Decreasing Airspeed. | - Increasing Rate of Descent.

Question 39

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

Answer 39

Light Windshear.

Question 40

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

Answer 40

Moderate Windshear.

Question 41

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

Answer 41

Strong Windshear.

Question 42

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

Answer 42

Severe Windshear.

Question 43

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

Answer 43

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

Question 44

Name two types of Icing that affects an Aircraft?

Answer 44

- Structural Icing. | - Induction Icing.

Question 45

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

Answer 45

Lift is reduced with the Stall Speed and Drag increasing.

Question 46

Name three factors which Icing has on Aircraft in flight?

Answer 46

- Increase in Weight. - Increase in Stall Speed. - Loss of Lift.

Question 47

Name three factors which determine the rate of Ice accumulation?

Answer 47

- Water. - Temperature. - Size of Liquid Drops.

Question 48

What is the Droplet Size for Clear Ice?

Answer 48

Large.

Question 49

At what temperatures will Clear Ice form?

Answer 49

0°C – 10°C.

Question 50

Name three hazards of Clear Ice?

Answer 50

- Rapid Build-up. - Possible Loss of Control. - Difficulty in Removing the Ice.

Question 51

What is the Droplet Size for Rime Ice?

Answer 51

Small.

Question 52

At what temperatures will Rime Ice form?

Answer 52

0°C – 20°C.

Question 53

Name two hazards of Rime Ice?

Answer 53

- Loss of Aerodynamic Efficiency. | - Possible Loss of Control.

Question 54

What is the Droplet Size for Mixed Ice?

Answer 54

Medium.

Question 55

At what temperatures will Mixed Ice form?

Answer 55

0°C – 15°C.

Question 56

How does Frost affecting flying (2)?

Answer 56

- Disrupt the Aerodynamic Efficiency. | - Reduce Visibility.

Question 57

Airframe Icing decreases what (2)?

Answer 57

- Lift. | - Thrust.

Question 58

Airframe Icing increases what (3)?

Answer 58

- Drag. - Weight. - Stall Speed.

Question 59

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

Answer 59

True.

Question 60

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

Answer 60

1-2 minutes.

Question 61

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

Answer 61

- Descend to a level where Temperature is above 0°C. | - Climb to a level where Temperature is below 20°C.

Question 62

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

Answer 62

Do not climb.

Question 63

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?

Answer 63

Clear the cloud by turning 180°C.

Question 64

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

Answer 64

- Unstable Atmosphere. - Sufficient Water Vapour. - Trigger Action (Type of Thunderstorm).

Question 65

True or False. All Cumulonimbus Clouds produce Thunderstorms?

Answer 65

False.

Question 66

Name three types of Thunderstorms?

Answer 66

- Frontal. - Air-mass. - Orographic.

Question 67

How are Frontal Thunderstorms formed?

Answer 67

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

Question 68

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

Answer 68

False. They are generally isolated.

Question 69

Name three types of Air-mass Thunderstorms?

Answer 69

- Heat. - Cold-stream. - Convergence.

Question 70

How are Heat Thunderstorms formed?

Answer 70

Through Convection by the heating from the ground.

Question 71

How are Cold-stream Thunderstorms formed?

Answer 71

When moist air is heated from below and becomes unstable.

Question 72

How are Convergence Thunderstorms formed?

Answer 72

When moist air is forced to raise

Question 73

How are Orographic Thunderstorms formed?

Answer 73

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

Question 74

Name three stages of a Thunderstorm?

Answer 74

- Cumulus. - Mature. - Dissipating.

Question 75

Cumulus Stage of Thunderstorm is dominated by what?

Answer 75

Strong Updrafts.

Question 76

How long does a Cumulus Stage last for?

Answer 76

15 minutes.

Question 77

Mature Stage of Thunderstorm is dominated by what?

Answer 77

Strong Updrafts and Downdrafts.

Question 78

How long does a Mature Stage last for?

Answer 78

20 minutes.

Question 79

Dissipating Stage of a Thunderstorm is dominated by what?

Answer 79

Strong Downdrafts.

Question 80

How long does a Dissipating Stage last for?

Answer 80

30 minutes to 1 hours and 30 minutes.

Question 81

Name four Thunderstorm Hazards?

Answer 81

- Turbulence. - Hail. - Icing. - Lightening.

Question 82

Where does the worst Turbulence occur in a storm?

Answer 82

Middle and Upper Levels.

Question 83

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

Answer 83

False. It does.

Question 84

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

Answer 84

By the roll of clouds.

Question 85

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

Answer 85

Hail.

Question 86

Where does Hail often appear to fall?

Answer 86

The overhanging ‘anvil’ of the storm.

Question 87

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

Answer 87

Upwind of the cloud.

Question 88

How can Lightning affect the stand-by magnetic compass?

Answer 88

Induce permanent errors.

Question 89

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

Answer 89

20.

Question 90

Name two types of Downbursts?

Answer 90

- Microbursts. | - Macrobursts.

Question 91

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

Answer 91

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

Question 92

Name three types of weather conditions where Microbursts can occur?

Answer 92

- Thunderstorms. - Rain Showers. - Virga.

Question 93

What dangers can Microbursts have on an Aircraft?

Answer 93

Low-level Windshear.

Question 94

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

Answer 94

- Increase. | - Increase.

Question 95

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

Answer 95

Conditions in Headwind and Tailwind.