MAS777
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Joined: Sun Jul 11, 1999 7:40 am

A380 Wake Turbulence

Fri Sep 10, 2004 5:58 am

As I do a lot of my flying on short-haul routes too - I have started to become increasingly nervous about wake turbulence, especially when I am sitting in a tiny 737 waiting to depart behind a 'heavy' aircraft. This fear seems to be worsening to the point that sometimes if I notice that a 747 is taking off ahead of mine - my mind starts wondering...

...anyway - personal fears aside - does anyone else have similar concerns about the A380's wake turbulence and distance separation required once it comes into service?

(Geez - sometimes the wait at LHR can be so long on the taxiways to take-off that I do hope that I never meet an impatient crew who just can't wait to get off the ground...)
 
gigneil
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RE: A380 Wake Turbulence

Fri Sep 10, 2004 6:44 am

Airbus did mention that they'd be putting in a lot of aerodynamic effort to minimze wake turbulence in any way they could...

...but it is huge, and displaces a lot of air. Only so much you can do.

N
 
oly720man
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RE: A380 Wake Turbulence

Fri Sep 10, 2004 7:04 am

Can't avoid the "heavy" problems. Big plane generates big vortices. Separation recommendations will be developed during test flying I'd imagine.
wheat and dairy can screw up your brain
 
cha747
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RE: A380 Wake Turbulence

Fri Sep 10, 2004 7:17 am

Are there any novel solutions to wake turbulence from the perspective of the ground? Could, I don't know, large fans be placed across and at the ends of the runway to negate the vortices that a jet creates? I'm sure plenty of people here know the physics of this and could intelligently respond.
You land a million planes safely, then you have one little mid-air and you never hear the end of it - Pushing Tin
 
jhooper
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RE: A380 Wake Turbulence

Fri Sep 10, 2004 7:40 am

One time I took off in a Cessna 172 right behind a C-5; that was exciting!
Last year 1,944 New Yorkers saw something and said something.
 
oly720man
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RE: A380 Wake Turbulence

Fri Sep 10, 2004 7:53 am

As far as dispersing wake vortices goes, nature tends to do it anyway. A vortex is a rotating tube of air and as it gets close to the ground it will roll sideways, if it's not already broken up. If there's any wind, the vortices will be blown with the wind. Having something to disperse them would be prohibitively expensive because they'd have to cover the whole length of the runway and a lot of power would be needed to generate enough flow velocity. The likelihood is that any dispersal system would cause more disruption than the vortices themselves

The vortices are a bigger problem in the air because they'll take longer to disperse.
wheat and dairy can screw up your brain
 
luisca
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RE: A380 Wake Turbulence

Fri Sep 10, 2004 8:05 am

i was doing some touch and go's in tocumen in preparation for my solo when I was told to hold for a lab 727 that was going to take of, I did all the procedures to avoid wake turbulance, landed before the pont where the aircraft took off, during the landing everything was fine, in the takeoff, things got ugly, i am not quite shure if i took of after the point where he rotated, but i defenetly croosed its path, it was horrible, i have never been shaken so much in an airplane ever. I was in a 152, next time i will wait till the turbulance disipates, i had only waited about a minute. that shure thought me a lesson.
If it ain't Boeing (or Embraer ;-)) I ain't Going!
 
DLKAPA
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RE: A380 Wake Turbulence

Fri Sep 10, 2004 8:24 am

Are there any novel solutions to wake turbulence from the perspective of the ground? Could, I don't know, large fans be placed across and at the ends of the runway to negate the vortices that a jet creates? I'm sure plenty of people here know the physics of this and could intelligently respond.

Even if there were a fan large enough, it would just make the problem worse.
And all at once the crowd begins to sing: Sometimes the hardest thing and the right thing are the same
 
AAgent
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RE: A380 Wake Turbulence

Fri Sep 10, 2004 11:23 am

Curious...

Here's an idea out of left field. And I suppose it would only work under visible light conditions, but I wonder what would happen if there was some sort of colored smoke emitted from the wingtips into the vortices that would create visible trails to warn following aircraft? You know something similar to the stuff used by sky writers to write messages across the sky. Makes me wonder??? (Of course the emission would occur only during takeoff, climb out, approach and landing cycles...not when cruising at altitude.)

Respectfully,
AAgent
War Eagle!
 
echster
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RE: A380 Wake Turbulence

Fri Sep 10, 2004 12:24 pm

AAgent,

Seems like a decent idea at first, but then does it become cost-prohibitive down the road? It's another system that needs to be added to an aircraft so it will need to be developed, tested, and approved for commercial aircraft. Who's going to pay for it?

Gigneil,

I've worked ATC for a decade and have never seen a wake turbulence problem so long as the time and separation standards were adhered to. When I fly, of all the things that potentially scare me, this is something I have never thought about.
 
RaginMav
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RE: A380 Wake Turbulence

Fri Sep 10, 2004 12:34 pm

I can hear it now...
Uh... Air Force One, we're gonna ask you to hold a few minutes to let that wake turbulence do its thing here...
 
Matheus
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RE: A380 Wake Turbulence

Fri Sep 10, 2004 5:20 pm

The worst aircraft to be after to is the 757!
Not exactly because its heavy, but because it inboard flap and outboard flaps is just one part! So, the it traffic separation is the same (maybe bigger) as the 747's, A340's etc. Maybe a traffic controller can explain this better!

Matheus
 
UAXDXer
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RE: A380 Wake Turbulence

Fri Sep 10, 2004 5:35 pm

Here is my experience with wake turbulence.............. KPDX - KDEN; UAL 733: As most of us know, anytime flying in & out of DEN turbulence is to be expected. On this particular flight (while listening to channel 9) we where experiencing the normal bumps flying over the Colorado Rockies, I heard ATC tell our flight deck crew that we where following a heavy 767, followed by the standard "caution wake turbulence". I didn't think anything of it because you hear this all the time. Not more than 30 seconds after that, in a blink of an eye, the aircraft violently knife edge to the right and back level then repeated one more time. Everything that wasn't secured went flying thru the cabin, luckily the FA's had already taken their seats, if they would have been up it could have been real ugly. After things settled down the Captain came over the speaker and said a larger aircraft (767 had descended informs of us causing the turbulence). Ever since then wake turbulence has paranoid the hell out of me.
It takes a bug to hit a windsheild but it takes guts to stick
 
AngelAirways
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RE: A380 Wake Turbulence

Fri Sep 10, 2004 5:56 pm

due to the large wing area and low wing loading (i.e. each square foot of wing carries less weight than on a 747, therefore each square foot of wing needs to produce less lift, therefore since less lift is produced, the wake vortices are also weaker)

so the wake turbulence will be equivalent or less than that of a 747.
noise will also be less due to the need for less flap in proportion.

(of course there is a trade off between wing loading and wing weight and skin friction so the optimum config nees to be found.)

 
aa777jr
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RE: A380 Wake Turbulence

Sat Sep 11, 2004 4:59 am

Mas777,

I feel your pain about waiting on the taxiways. I fly often from ORD-LHR on AA and the wait on the runway at ORD is getting increasingly more and more unbearable. Sat on the runway waiting in line for 90+ mins on my last flight to Europe.

AA777jr
A liberal is a man who is right most of the time, but he's right too soon.
 
Hodges
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RE: A380 Wake Turbulence

Sat Sep 11, 2004 5:13 am

I think we need to remember that wake turbulence can threaten many larger aircraft. Look at the AA A300 that crashed in Queens in November 2001. Crash investigators believe the vertical stabilizer fell off of the plane due to multiple factors, however, the wake turbulence casue by a JAL 747 (correct me if I'm wrong) was the straw that broke the camel's back.

Erik
Beer, helping ugly people have sex since 1862.
 
DAYflyer
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RE: A380 Wake Turbulence

Sat Sep 11, 2004 5:28 am

Taking off in a 737 after a 380 will be like surfing in a hurricane. Got Sea legs?
Your gonna need 'em!
One Nation Under God
 
Alessandro
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RE: A380 Wake Turbulence

Sat Sep 11, 2004 5:33 am

So how is the wake turbulence after the AN-225?
From New Yorqatar to Califarbia...
 
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Starlionblue
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RE: A380 Wake Turbulence

Sat Sep 11, 2004 7:43 am

Crash investigators believe the vertical stabilizer fell off of the plane due to multiple factors, however, the wake turbulence casue by a JAL 747 (correct me if I'm wrong) was the straw that broke the camel's back.

Sort of, but it's the other way around. Wake turbulence started a chain of events in which the pilots had to compensate for the turbulence, eventually leading to the snapping of the tail.
"There are no stupid questions, but there are a lot of inquisitive idiots." - John Ringo