Crosswind takeoff or windshear?

[Vibes]

Hi Folks,

With regards to the video below,is the sudden disturbance caused by windshear or crosswind?If so,how do you differentiate between the two?

I know its a silly question to ask as its already stated in the video's title but I just want to know more.

YouTube - C-17 Globemaster III Short Crosswind takeoff. (http://www.youtube.com/watch?v=02_0piR13qo)

[trex450]

looks more like it is pilot induced to me, I say that because the roll rate and angles are almost identical in each direction.

[proxus]

I would say that's the pilot(s) rocking their wings as a good bye.

[John Farley]

Agreed normal use of aileron by pilot.

There is no such thing as a silly question - but you can always tell when an aircraft is affected by a cross wind as in the first moment after unstick the nose will move (yaw) sideways into the crosswind. So wind from the right nose will go to right.

A wind shear is the term used for a sudden and marked change in the local wind strength (and perhaps direction). Passing through a wind shear gives a sudden and marked change of airspeed, which if it results in a loss of airspeed can suddenly reduce the lift available. A sudden loss of height/sink with no change in aircraft attitude (following a period of stabilised flight) could indicate a windshear.