"Roger Long" wrote in message
...
Think of them as being like invisible ropes trailing from the
wingtips. They are small so your chance of hitting one is small. If
you do however, the probability of death from the upset at such low
altitude is very high.

They do trail like ropes so staying above the flight path(s) is basic.
There are accounts of them hitting the ground and bouncing back up
again which could ruin your day if you went through one just before
you flare.

To Roger:

Although the characterization of them as a rope is accurate in a way, I
don't think that is correct to say that they are small.

To Ramapriya:

I have seen pictures of a 747 going through the rising smoke of a brush, or
forest fire, and the circulation of the smoke very clearly showed the size
of the disturbance. The diameter of the circulation was perhaps half of the
747's wingspan, as close as perhaps 10 plane lengths behind it. It was
completely invisible, except for the smoke in the air.

Sometimes in periods of high humidity, there is a very thin, rope-like
circulation behind the plane. I liken it to the eye of the hurricane, and
the circulation of the hurricane and it's tropical force winds reach far out
from the center of the storm.

Wake vorticies from a small plane are felt while the small plane is making
circles in the sky, they will often feel a sharp bump as they cross their
own wake. Now multiply that by many times.

It is interesting to note that although the 747 is one of the largest
planes, it does not have the worst wake reputation. I believe it is the 757
that is said to have more powerful wake vorticies.

I do wonder how the new Airbus 380 will trail the vorticies? They say it
will be no worse, but of course they would say that. g
--
Jim in NC