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Wake turbulence zone
The region behind the aircraft containing the trailing edge vortices
The vortices produced by an aircraft are directly proportional to what?
the amount of lift being produced
Greatest vortex strength will occur when?
Generating aircraft is heavy, clean and slow
How big is the vortex core diameter?
Diameters equal about 1/4 of the generating aircrafts wingspan
As the vortices trail behind the aircraft, how close do they stay together?
- about 3/4 the wingspan.
- They tend to interact creating a even larger field of influence
Small airplanes should avoid operating within ____ rotor diameters of any hovering helicopter.
What is the minimum spacing required behind a heavy aircraft (>250,000lbs)?
- 2 minutes
- Also encouraged behind large aircraft (41,000-250,000lbs)
At what points on landing and takeoff are wingtip vortices generated or stopped?
- Takeoff- aircraft rotates
- Landing- nose gear touches down
A sudden change in wind direction and/or speed over a short distance in the atmosphere
Increasing performance wind shear
lift and climb performances will increase
Decreasing performance wind shear
lift and climb performance will decrease
What happens to an aircraft on landing when encountering a decreasing performance wind shear?
aircraft pitches down and descends below the glidepath
Characteristics of a microburst
Generally small, associated with heavy rain showers and usually short-lived, less than 20 min
Initial effects of a microburst on an aircraft.
- Strong increase in headwind
- Increase in IAS
- Aircraft pitches up and climb
Late effects of a microburst on an aircraft?
- Severe downdraft
- Headwind shifts to a strong tailwind
- Loss of IAS
- Aircraft pitches down and descends
Clues that wind shear exist include:
gusty winds; heavy rain; thunderstorms
Visual clues of microburst activity include:
virga; localized blowing dust; rain shafts with rain diverging away from core of the cell; lightning; tornado-like activity