Sam_87

After a flight on Friday, I thought back to a flight a couple of weeks ago on AKL - CHC where the captain had to stop on the taxiway at AKL and annouce on intercom that ATC had advised them to stop and wait 5-10 mins, for the EK A380 to get clear after takeoff.

This is apparently due to back draft from the large Aircraft causing turbulence, is this even a thing, or just an excuse from NZ and ATC?

yotty

It's absolutely a thing. It's called wake turbulence and highest risk generally during take off and landing.

A private jet (Challenger 604) recently lost control mid-flight after passing underneath an A380 and hitting its wake.

nzkarit

A380 has most wake turbulence. ATC have to juggle size of planes and spacing.

The A380 wake turbulence versus a business jet:
https://avherald.com/h?article=4a5e80f3
http://flightservicebureau.org/enrou...4-upside-down/
https://theaviationist.com/2017/03/1...ake-near-oman/

macdo

And the time between aircaft - landing or taking off - that is required for the wake turbulence to settle to safe levels is one important economic driver of airport and airline efficiency.

LyingFlat

The people on board that Challenger were lucky they weren't killed.

http://www.stuff.co.nz/travel/travel...rolled-descent

Sam_87

Well there you go.. thought it was just an excuse for losing space in queue after a delayed departure.. thanks!

nzkarit

Ahh so running late. ATC would normally try and arrange things so don't get delays like that.

If anything like WEllington they will havea view of the planes on the gates and know state like boarding, door closed etc so they start planning things before they even ask. It is all about maximising airport through put.

The second runway will be handy as all the smaller planes can use that and avoid the wake of the heavies and super heavies. (ignoring the taxi times as the terminals and runways are the wrong way around.)

jawnbc

And it brought down https://en.wikipedia.org/wiki/Americ...nes_Flight_587 in Queens, a couple of months after 9/11.

I was there, 2 blocks away. Insane.

dadig

The winglets in the 380 was designed to reduce the turbulence ?

SpannerSpinner

winglets are always to reduce drag. No matter how you look at it you need to move a LOT of air to get/keep a fully loaded A380 (~570tons) airborne.

WorldLux

Certainly a contributing factor but IIRC the issue of wake turbulence was only one of the contributing factors. The flight crew's incorrect (or rather excessive) reaction was blamed too by the NTSB.

Irrespective of what was the predominant factor in that accident, wake turbulence are a serious business.

I had a couple of Cessna Grand Caravan flights out of international hubs and we had to wait 20 or 30 minutes until we were cleared for takeoff: ATC put us behind all the big, scary 747s, A340 (there were no A380 at the time) and we took off long after a 737 Next Gen.

Still not going to change much if you over 500 tons airborne. It's going to cut through the air and create turbulence behind it. Even a car or a truck driving at reasonable speeds creates turbulences behind it. Stand at the side of the road and wait for a semi-truck. The pull they generate at 60 or 70mph is quite impressive (and dangerous if you're too close as pedestrian).

zrs70

First, others have explained the wake turbulence effect.

But why the question? Is it just an excuse .... Do you think they delayed for another reason and didn't want to tell the truth?

ROCAT

I would doubt it is an excuse, controllers try and put like types together but at times it is impossible do to many factors (flight directions, other runway traffic, release times, etc) but at times you just get stuck.

I was in a jumpseat of a B753 and was 6.5 in trail and 2k below a A388 and we even got rocked hard. In general controllers are advised if possible to sidestep aircraft behind A388 to minimize issues. This is easier for the enroute people to do then for terminal controllers.