Wake vortices... a sterile danger?

I was at a place today from where I had a nice, clear view of the Dubai
Airport runway all day long. For about 3 hours in the morning, and
another 2-hour period in the afternoon, a string of aircraft took off
virtually tailing one another. Most of them were A330s, and the rest
were 747s and A340s, with the odd A320 and 737.

Makes me ask you folk this... are wake vortex caveats for real? How do
you manage when in a queue of big jets?

Ramapriya
ayirpamarATgmailDOTcom

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.

--

Roger Long



"Ramapriya" wrote in message
oups.com...
I was at a place today from where I had a nice, clear view of the
Dubai
Airport runway all day long. For about 3 hours in the morning, and
another 2-hour period in the afternoon, a string of aircraft took
off
virtually tailing one another. Most of them were A330s, and the rest
were 747s and A340s, with the odd A320 and 737.

Makes me ask you folk this... are wake vortex caveats for real? How
do
you manage when in a queue of big jets?

Ramapriya
ayirpamarATgmailDOTcom

"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

Morgans wrote:

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.

I once inadvertently crossed a B727 wake perpendicularly. It was like
slamming into a large pothole at speed in an automobile.

--
Peter

"Peter R." wrote

I once inadvertently crossed a B727 wake perpendicularly. It was like
slamming into a large pothole at speed in an automobile.

So did you take it into the shop to get the front-end aligned? It surely
must have needed it, after that! g
--
Jim in NC

Morgans wrote:

So did you take it into the shop to get the front-end aligned? It surely
must have needed it, after that! g

My jaw needed to be re-aligned after that bump.

--
Peter

"Morgans" wrote

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.


It's the killer part that is small. You are right that the
disturbance extends much farther. The people who were scared, nearly
died, and lived to tell us about it hit that outer disturbance. Not
many have described hitting the rope in the middle. They are a lot
like tornadoes. Look how close the chasers get to the funnels where
they are pelted by debris but live. Then consider the devastation at
the center.

--

Roger Long

I fly John Wayne. Parrallel runways Always a crosswind. Jets +
Cessnas. Always a wake concern.

Early turn out into the wind. Land long. Take off short. Approach high
and steep. Lots of slips.

If on an ILS keep 1 dot into the wind and 1 dot high. Takes care of it.

Ramapriya wrote:

How do you manage when in a queue of big jets?

When flying into and out of Boston Logan airport in a Bonanza and assuming
the weather is not low IFR, I request an early turnout away from the
descending wing tip vortices.

The big jets take a lot more runway than I do and normally climb a thousand
or so feet before turning, so when at a large airport where reality is that
ATC is not grant me a three minute hold for wake turbulence (instead, they
will move me out of the way and the three minute hold works out to more
like an hour wait while jet after jet departs), I lift off immediately -
short field takeoff - then with tower approval begin an early turnout away
from the runway.


--
Peter

fwiw, make that turn request upwind if you can.