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What are the four levels of turbulence intensity?
- Light: slight strain
- Moderate: Definite strain
- Severe: Large, tossed about, abrupt changes
- Extreme: violently
Which direction would you exit the jet stream?
What are the four classifications of turbulence?
- Wind shear
What type of frontal activity is likely to produce the most turbulence?
Fast-moving cold front
What type of icing is found in cumuliform clouds and unstable conditions?
What are the aerodynamic effects of icing?
- Changes/reduces stall AOA
- Stall speed goes up
- Decreases lift, thrust, range
- Increases weight
T or F: Is the pitot-static system affected by ice?
What are the ground hazards of icing?
- Splashed on aircraft surfaces
- Can freeze later at higher altitudes
- Hazardous to control during braking of aircraft
What should you do if you encounter freezing rain?
Climb into warm front front or inversion
- Trace: becomes perceptible; anti/de-ice not used
- Light: Can be a problem; not a problem with anti/de-ice
- Moderate: potentially hazardous
- Severe: rate of accumulation extreme; anti/de-ice cannot keep up with ice accumulation
What type front produces the most significant icing conditions?
What are the greatest hazards associated with induction and compressor icing?
Reduced airflow and FOD
What conditions are necessary for the formation of aircraft icing?
Visible moisture and temperatures between 0° and -20°C
Define slant range visibility.
The distance on final approach at which the new runway environment is in sight
What is the minimum sky coverage constituting a ceiling?
5/8 (broken) or a total obscuration
Which fog forms generally between 1530 and the time when the sun starts warming the surface?
What are the three requirements that define fog?
- Base at or within 50' of surface
- Greater than 20' thick
- Reduces visibility to less than 5/8 mile
T or F: Advection fog is dissipated by solar heating?
- The fog layer is usually too thick for solar heating to be effective
If an aircraft encounters an ash cloud in flight what is the best procedure for the pilot to use to escape the cloud?
Execute 180° turn
What category of turbulence is characterized by large variations in airspeed and abrupt changes in attitude and altitude?
Turbulence occurring less than 1/3 of the time is described as _____.
Moderate turbulence can extend as far as _____ miles downwind of a mountain wave.
What are the three types of wind shear turbulence?
Jet stream, gusty winds, temperature inversion
What are the two types of engine icing?
Compressor and induction icing
T or F: Induction icing requires visible moisture and sub-freezing temperatures.
- Induction icing is a result of lower inlet pressures, and can occur in clear air and temperatures as high as 10°C
T of F: When flying yourself in icing conditions, you can escape by flying into areas of colder temperatures.
- At lower temperatures precipitation is already frozen and aircraft icing is not a hazard
At what intensity of icing is rate of accumulation a problem if encountered for an extended period of time?
Total visibility over half the horizon circle or greater is _____.
_____ is the distance that can be seen directly upward from the ground into a surface-based obscuration.
Vertical visibility (VV)
Which type of fog produces a thicker, more persistent layer?
Is there turbulence in a warm front?
no due to little or no lifting
Duration of turbulence
- Occasional: less than 1/3 of the time
- Intermittent: 1/3-2/3 of the time
- Continuous: more than 2/3 of the time
What is a mountain wave?
Strong winds blowing perpendicular to a mountain range
Rule of thumb for turbulence proximity/intensity:
- 50 knots wind at altitude of peak - extreme
- Up to 150 miles downwind - severe
- Up to 300 miles downwind - moderate
What is a rotor cloud?
- Form downwind from and parallel to mountain range
- Cylindrical shape
- Downward flow has been know to reach the ground
What is a cap cloud?
- Cover top of mountain
- Remain stationary
What is a lenticular clouds?
Form on leeward side of mountain from standing waves
- Large water droplets freeze slowly, spreading out and assuming shape of airfoil
- 0° to -10°C
- Found in cumulus clouds; unstable conditions
- Small water droplets freeze instantaneously retaining shape
- Found in stratiform clouds; stable conditions
- -10° t -20°C
- Combination of clear and rime
- Lumpy but hard and dense
- -8 to -15°C
- Most common type
Occurs on clear, calm nights
Frontal icing - Warm front
- Stratiform clouds
- Rime ice
- Low rate of accumulation
- Widespread are of icing
Frontal icing - Cold front
- Cumuliform clouds
- Clear icing
- High rate of accumulation
- Limited area of icing
Frontal icing - Occluded front
- Mixed clouds - stratus and cumulus
- Rime, clear and mixed
- Rapid and heavy accumulation
- Very widespread area of icing
- Caused by nocturnal radiation cooling
- Light winds
- Dissipation begins as sun warms surface
- Warm moist air moves over cool surface
- Usually forms over water
- Only wind shift can dissipate
What are the two types of routine weather observation reports?
_____ are used to determine whether a field is operating under conditions of instrument flight rules (IFR) or visual flight rules (VFR).
A ____ is an unscheduled observation containing all the data elements found in a METAR whenever critical data have changed from the previous observation.
A constant temperature with increasing altitude is an example of a ___ lapse rate.
The altimeter setting is corrected for ____.
sea level pressure (SLP)
High pressure results from ___ air.
Cloud types in low clouds
Cloud types in middle clouds
Types of clouds in high clouds
____ clouds produce violent/heavy steady precipitation.
What are the methods of lifting?
What properties are used to locate and classify fronts?
- Dew point
What parameters of an air mass are generally uniform when measured across a horizontal plane?
Temperature and moisture
What are the characteristics of a squall line?
- Line of severe thunderstorms
- Forms 50-300 miles ahead of a cold front
- Will sometimes form without a cold front
- Contains severe hazards to aviation
With a warm front, does weather occur ahead of or after a surface front?
Weather occurs ahead of a surface front
An occluded front is formed when a _____ front overtakes a ____ front.
T or F: A wind shift and temperature change do not occur during the passage of an inactive front.
- Wind shift and temperature change still occurs
During ____ you will experience large abrupt changes in altitude and/or attitude.
Thermal turbulence is also know as ____.
To avoid icing, why would climbing to a colder temperature be a consideration?
Frozen moisture is not an icing hazard
What are the types of obscuring phenomena?
- Rain and drizzle
- Blowing snow, dust or sand
What is a ceiling?
- Lowest broken or overcast layer
- Vertical visibility (VV) into an obscuring phenomenon
What are some indications of flying into volcanic ash?
- Torching from engine tailpipe
- St. Elmos fire
- Bright glow in engine inlets
Will you experience any turbulence in volcanic ash?
What are some hazards of flying into volcanic ash?
- Multiple engine malfunctions
- Pitted windscreens
- Sandblasting of external surfaces
What is the cause of electrostatic discharge?
Results from positive and negative charge, from water and ice passing in up and down drafts
What is the sequence of events a pilot will encounter when flying through a microburst?
- Increasing headwind and indicated airspeed
- Tailwind and decreasing indicated airspeed
What are the atmospheric cycles?
- Evaporation and condensation
- Hydrological cycle
The ____ is used to determine air mass boundary.
What type of clouds indicate the presence of low level wind shear and extreme turbulence?
Roll and wall clouds