AviationBanter - View Single Post

**Mxsmanic** · April 16th 07, 03:55 PM posted to rec.aviation.piloting,rec.aviation.student

writes:

Upon what do you base the assumption your wake should decend 150'?

All wakes descend; they have to, otherwise the aircraft could not stay aloft.
They move at a few knots, which still amounts to some 500 fpm.

I have never heard of any study of the wake properties of GA aircraft
and the wake of a C172 is very different than the wake of a 747 ...

Since you haven't heard of any study of the wake properties of GA aircraft,
you cannot possibly know whether the wake of a C172 is "very different" from
that of a 747 or not. Oops!

In fact, the general principle is the same for all aircraft wakes. They
always move downward gently. You cannot catch them in a turn unless you move
downward, too. If you are in rising air, the wake might remain stationary
relative to the ground, but then your aircraft would be rising, so you'd still
have to descend relative to the surrounding air in order to catch your wake.
And smoothly rising air isn't that common, although it's not that rare.

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