Wake Turbulence Flashcards
What is Wake Turbulence?
Rotating air masses generated behind the wing tips of aircraft, or behind rotor tips of helicopters in forward motion.
What are rotating air masses generated behind the wing tips of aircraft, or behind rotor tips of helicopters in forward motion?
Wake Turbulence
What are Vortices?
- Circular patterns of air
- created by the movement of an airfoil
- through the air when generating lift.
- Rotating column of air;
- can be hazardous to aircraft.
What are Circular patterns of air created by the movement of an airfoil through the air when generating lift. Rotating column of air; can be hazardous to aircraft?
Vortices
What is Clean Configuration?
When an Aircraft is configured for flight with no flaps, gear retracted, and no other wing extensions, such as air brakes.
What is the configuration when an Aircraft is configured for flight with no flaps, gear retracted, and no other wing extensions, such as air brakes.
Clean Configuration
What is Dirty Configuration?
Aircraft is configured for flight with flaps, gear extended, and additional wing extensions, such as air brakes.
What is the configuration when the Aircraft is configured for flight with flaps, gear extended, and additional wing extensions, such as air brakes?
Dirty Configuration
What is Rollup Effect?
- Difference in pressure above/below an airfoil
- results in airflow twisting into
- counter-rotating cylindrical vortices.
What is the difference in pressure above or below an airfoil that results in airflow twisting into counter-rotating cylindrical vortices?
The Rollup Effect.
What is an Induced Roll?
Mechanical force a wake vortex has on an aircraft. Without counter action, causes an aircraft to roll/spin on its longitudinal axis.
What is the Mechanical force a wake vortex has on an aircraft called?
Induced Roll
What is Downwash?
- Wake turbulence generated from helicopters
- in a slow or stationary hover,
- pushing downwards and
- outwards from the rotor.
What is Wake turbulence generated from helicopters in a slow or stationary hover, pushing downwards and outwards from the rotor called?
Downwash
What is Jet Blast?
Exhaust from a jet engine.
What is Exhaust from a jet engine called?
Jet Blast
What are the three factors that determine the intensity of wake turbulence?
Weight of the aircraft
Speed of the aircraft
Shape (configuration) of the airfoil
Do all aircraft generate wake turbulence in flight?
Yes
What effect does the weight of an aircraft have on wake turbulence?
More weight generates a higher force of turbulence.
What is the most important factor for wake turbulence intensity?
Weight of the aircraft.
What effect does the speed of the aircraft have on the wake turbulence?
Slower speed generates higher force.
What effect does the speed of the aircraft have on the vortices it produces?
Vortices dissipate quicker at higher speeds.
What effect does shape (configuration) of the airfoil have on wake turbulence?
Clean configuration generates higher force.
How does wake turbulence diminish?
With time and distance from origination.
When does a vortex begin?
Whenever an aircraft generates lift.
When does a vortex end?
When lift is no longer produced.
How do vortexes rotate?
Towards the aircraft.
How do vortexes drift?
Away from the aircraft.
At what rate do vortexes sink?
300’-500’ per minute
How do vortexes move at or near ground level without wind?
Away from the aircraft at 2-3 knots.
At what altitude will vortexes move away from the aircraft at 2-3 knots?
Ground Level
How will small crosswinds affect the movement of vortexes?
Will stall movement of one vortex, and increase movement of the other.
How do tail and headwinds affect the movement of vortexes?
Push the vortices in the direction they are blowing
What are the 2 most common types of wake turbulence hazards?
- Structural
2. Induced Roll
What hazard causes loss of aircraft control?
Induced Roll
What two factors affect an aircraft’s ability to recover from induced roll?
Wingspan
Counter control capability
When is counter control most effective?
When wings extend past the edges of the vortex.
When can Induced Roll be encountered?
Unpredictable and can be encountered in flight or on the ground.
What are the 4 downwash characteristics of a helicopter?
High speed vortices.
Pushes outward (away) from the rotor as it reaches the ground.
Expands to approximately three times the rotor diameter.
Expands in all directions.
What are the 3 Vortex Characteristics of a Helicopter?
Wingtip vortices generated in forward flight.
Similar to fixed wing.
May be stronger than vortices from similar mass fixed wing aircraft.
What is mandated to account for an mitigate the effects of Wake Turbulence?
Increased separation between aircraft.
What can increased separation increase?
Delays
Are controllers responsible for anticipating the existence or effects of wake turbulence?
No
What do controllers need to issue in response to wake turbulence?
Cautionary advisories
What is the cautionary advisory phraseology to issue in response to wake turbulence when the aircraft is on the ground?
CAUTION JET BLAST /PROPWASH
/ROTORWASH
What is the cautionary advisory phraseology to issue in response to wake turbulence when the aircraft is in the air?
CAUTION WAKE TURBULENCE
