Jet stream

[lovejoy0120]

What are those winds that can be encountered rarely during flying that are far worse than turbulence ?

thanks

[mibn2cweus]

windsheer

[heathfield]

Jet stream winds are generally forecast and taken into account in aircraft flight planning. 'Clear Air Turbulence' (CAT) is the dangerous one, since it can set up 'wind shear'. Wind shear occurs when two sets of wind are moving next to each other at different speeds and in different directions without mixing. Thus a plane can meet a catastrophic change in wind speed and direction within seconds. It's concluded that this is what happened to a British Airways VC10 that flew close to Mount Fujiyama on the start of its trip back to the UK from Japan - the plane simply broke apart in a clear blue sky.

On another occasion a Northwest Airlines plane flying above the weather over the US suddenly went nose-up and straight into a 'high-speed stall'. The pilots recovered control only after managing to dive the plane on full power, almost reaching the speed of sound, so they reckoned, and pulling out very close to the ground. It was calculated that out of a clear sky, the plane suddenly encountered a head wind in excess of 80 mph.That's what CAT can do..

[Toureman]

Good explanation here....

http://www.geo.mtu.edu/department/classes/ge40 6/jmedward/windsheer/deadly.htm

[Toureman]

Type windsheer in the search box.

[lord molly]

the jet stremes are no rare. there are two main bands of them aroung the globe. they can often helf aircratf in flight. they are not usually turbulant though, as all the air is moving in the same direction

[heathfield]

What's with this wind-'sheer' business? In the context of the question, the word is windshear

Alas! I blame the poor standard of American education for such errors creeping into UK English, resulting in a gradual erosion of meaning. (Sorry, Clanad, but...)