Turbulence

Question 1

Turbulence intensity

Answer 1

Light
Movement is easy
Slight change in alt or attitude

Moderate
Ac remains in positive control
Food service and movement difficult
Variations in IAS

Severe
large abrupt changes in alt, att, IAS
Ac may be momentarily out of control
Movement impossible

Extreme
Impossible to control can cause structural damage
Strong desire to land

Question 2

Small scale turbulence

Answer 2

Mechanical lifting
Generally within friction layer
Wind below 15 kts
Turbulence within 1/3 height above obstruction
Can extend several km horizontally

Question 3

Large scale turbulence

Answer 3

Large obstructions like mountain ranges
Strong wind causes air to eddy
Moderate to severe on leeward side

Question 4

Turbulence factors

Answer 4

Speed of wind
Size of obstruction
Shape of obstruction
Stability of air

Question 5

Clear air turbulence (CAT)

Answer 5

Sudden severe turbulence in cloudless conditions causing violent buffeting
Higher altitudes
Associated with wind shear

Question 6

Worst case wake turbulence

Answer 6

Leading ac
Large and heavy
Slow (high aoa)
Clean (flaps up)

Crosswind reduces effect
Fly above flight path