Wake Turbulence

Question 1

Wake turbulence

Answer 1

Disturbance in the atmosphere that forms behind an aircraft as it passes through the air

Question 2

Causes of wake turbulence

Answer 2

Wing-tip vortices
Rotor-tip vortices
Jet engine thrust stream
Rotor downwash
Prop wash

Question 3

Wing-tip vortices

Answer 3

Created as air flow outward from body of aircraft to wing tip

High pressure underneath rotates upward toward low pressure

Vortices rotate inwards

Question 4

Rotor-tip vortices

Answer 4

Created by rotor blades of a helicopter

Helicopter’s lower operating speed produce higher intensity wakes than fixed-wing aircraft of similar weight

Question 5

Jet engine thrust stream

Answer 5

Turbulence created behind an aircraft’s jet engine

Extreme but short duration

AKA jet wash/ jet blast

Question 6

Rotor downwash

Answer 6

Downward turbulence created by helicopters hovering/ in forward flight

Question 7

Prop wash

Answer 7

Turbulence created by any propeller driven aircraft

Same principle as jet engine thrust stream

Question 8

Induce roll

Answer 8

Uncommanded roll caused when an aircraft is flying directly into the core of a vortex

Question 9

Ground effect

Answer 9

Created by wing tip vortices generated behind departing/ arriving/ aircraft that descend to less than 100ft above runway

Can move laterally at ~5knots (no wind conditions)

Question 10

Weight categories of aircraft

Answer 10

Light (up to 7000kg/ 15500lbs)

Medium (7 000kg - 136 000kg/ 15 500lbs - 300 000lbs)

Heavy (136 000kg +/ 300 000lbs +)

Super (ex. A380)