NIFE Weather 6-3-2 Hazards

Question 1

2.202

Define turbulence

Answer 1

-Any irregular or disturbed flow in the atmosphere producing gusts and or eddies

Question 2

2.203

List the intensities of turbulence used in Pilot Reports (PIREPs)

Answer 2

-Light, Moderate, Severe, Extreme (Relative to aircraft)

Question 3

2.204

Define the terms used to report turbulence with respect to time

Answer 3

• Occasional (less than 1/3)
• Intermittent (1/3 to 2/3)
• Continuous (greater than 2/3)

Question 4

2.205

Describe the causative factors that create the different types of turbulence

Answer 4

• Thermal: surface heating pushing the air mass up
• Mechanical: caused by differences in terrain
• Frontal: Lifting of warm air by a frontal surface leading to instability
• Wind shear: Steep gradient in wind velocity
• Jet stream: Produced by fast wind shears at high speeds just below the tropopause.

Question 5

2.206

Describe how thermal turbulence develops

Answer 5

Surface heating pushes the air mass up causing instability

Question 6

2.207

Describe how mechanical turbulence develops

Answer 6

Differences in terrain cause shift in air mass i.e. buildings, mountains, and water

Question 7

2.208

Describe how frontal lifting creates turbulence

Answer 7

Warm air is lifted by a frontal surface leading to instability, or by abrupt wind shift between the warm and cold air masses.

Question 8

2.209

Describe how temperature inversions are examples of wind shear turbulence

Answer 8

• Turbulence can occur at the boundary between the inversion layer and the surrounding atmosphere
• may cause a loss of lift

Question 9

2.21

Describe the primary hazard of low level wind shear turbulence

Answer 9

-Can produce loss of lift by producing a downdraft or changing a headwind to a tailwind

Question 10

2.211

Describe how jet streams are examples of wind shear turbulence

Answer 10

-Rapid change of wind speed within a short distance of the jet core is particularly significant

• If temperature rises–climb
• If temperature falls–descend

Question 11

2.212

Describe the recommended procedures for flying through turbulence

Answer 11

-Monitor outside temperature for a minute or two

• If temperature rises climb
• If temperatures fall descend
• If temperatures remain the same either climb or descend

Question 12

2.213

Describe structural icing

Answer 12

Ice forming on the airfoils changing the camber and weight of the aircraft

Question 13

2.214

State the requirements for the formation of structural icing

Answer 13

• The atmosphere must have super-cooled visible water droplets
• The free air temperature and the aircraft’s surface temperature must be below freezing

Question 14

2.215

State the temperature range most conducive to structural icing

Answer 14

• The smaller the droplets the lower the freezing point
• Freeze between -10C and -40C
• Icing is possible in any cloud below 0C

Question 15

2.216

Identify the hazards of aircraft icing

Answer 15

• Icing decreases lift, increases drag, weight, fuel consumption, and stall speed.
• Can alter the shape of the airfoil changing the angle of attack.

Question 16

2.217

Describe the types of engine icing

Answer 16

Induction- Ice buildup in the inlets (can occur above freezing due to increase in static pressure)

Compressor- Ice formation on the compressor inlet screens and compressor inlet guide vanes will restrict the flow of inlet air, eventually causing flame out

Question 17

2.218

Identify the procedures to minimize or avoid the effects of icing

Answer 17

• Anti-icing/De-icing equipment
• Avoid icing forecasts
• Avoid clouds with 0C to -20C
• Avoid freezing precipitation
• Avoid low clouds above mountains
• Avoid steep turns into ice
• Change altitude to temperatures above freezing or below -20C

Avoid flying parallel to fronts

Question 18

2.219

Describe the parameters that define fog

Answer 18

• Based at or within 50ft of the surface
• Greater than 20ft in depth
• Reduces visibility to less than 5/8 of a statute mile
• Shallow, is no more than 200ft in height

Question 19

2.22

Define obscuring phenomena

Answer 19

• Any collection of particles that reduce horizontal visibility to less than six miles
  e. g. fog, smoke, volcanic ash, and blowing spray

Question 20

2.221

State the requirements for fog formation

Answer 20

• Condensation nuclei must be present in the air
• The air must have a high water content (low dew point spread)
• light surface winds must be present

Question 21

2.222

Describe the two main types of fog

Answer 21

-Radiation: Occurs due to nocturnal cooling, usually on clear nights, when the Earth releases relatively large amounts of radiation to the atmosphere, cooling the surface.

Advection: Warm, moist air moves over a cold surface and the air is cooled to the dew point (sea fog) can last weeks (land at day/sea at night)

Question 22

2.223

Describe the hazards associated with thunderstorms

Answer 22

-Strong wind gusts, severe turbulence, lightning, heavy rain showers, severe icing, and possible hail and tornadoes

Question 23

2.224

Describe the signs and hazards associated with microbursts

Answer 23

• Strong headwind changes to a strong tail wind (decreasing lift)
• Doppler calls for low-level wind shears
• Visual cues are virga, localized blowing dust, rain shafts, roll clouds, and lightning or tornado like activity

Question 24

2.225

Describe the recommended techniques for avoiding thunderstorm hazards

Answer 24

• Get latest radar report and PIREP
• Wait out the storm
• Avoid the thunderstorm by at least 20 miles of the anvil
• Don’t fly below in mountainous terrain
• Always avoid flying through a thunderstorm