A380's "unusually powerful wake."

PYX · Post by **PYX** » 23 Nov 2005, 08:10

I've been hearing something about the A380 having such a "unusually powerful wake" that the International Civil Aviation Organization has proposed 10 nautical miles (normally 5) minimum separations for all aircraft following a landing A380, and for aircraft flying the same route directly behind an A380 at cruising altitude a minimum spacing of 15 nautical miles (normally 5).
Anyone else heard anything about this?

lastrow · Post by **lastrow** » 23 Nov 2005, 09:22

apparently this issue has been covered by an ICAO report released in the past days. more can be read here:
http://www.airliners.net/discussions/ge ... n/2437407/

regi · Post by **regi** » 23 Nov 2005, 09:40

It is one of the measures of the Capital of the Free World to avoid free enterprise. See Concorde story.

lastrow · Post by **lastrow** » 23 Nov 2005, 10:18

inparticular, the following letter (if not faked!) is very interesting:

http://www.airliners.net/discussions/ge ... 37407/#193

it is the statement of the ICAO Director for Europe/North American

WreckageTrail · Post by **WreckageTrail** » 23 Nov 2005, 13:04

It is one of the measures of the Capital of the Free World to avoid free enterprise. See Concorde story.

Fully.

Allnipponairways · Post by **Allnipponairways** » 24 Nov 2005, 13:12

how bigger the aircraft how bigger the engines needed and so maybe the flow will be longer and harder not to get the air back in order after the engines .. but the more people on board the less aircraft needed no ??
greets

vc-10 · Post by **vc-10** » 24 Nov 2005, 14:46

Yes but the A380 will tke up more space, more than 2 A340s/777s.

bits44 · Post by **bits44** » 28 Sep 2006, 21:39

JAA,FAA, and Airbus have concluded wake study, and have recommended additional spacing.

http://tinyurl.com/qp3be

Post by **ElcoB** » 28 Sep 2006, 22:33

bits44 wrote:JAA,FAA, and Airbus have concluded wake study, and have recommended additional spacing.

Ah yes; but only for following aircraft on approach and landing.

Horizontal spacing en-route.............the same as for other aircraft.
......
Vertical spacing in all cases to be the same as for other aircraft.
.......
Holding; Vertical spacing to be the same as for other aircraft.
.......
Approach / Landing: A380 followed by Heavy = +2nm extra to existing ICAO separation (6 nm absolute distance)

A380 followed by Medium = +3nm extra to existing ICAO criteria (8 nm absolute distance)

A380 followed by Light = +4nm extra to existing ICAO separation criteria (10 nm absolute distance)

Mordoch · Post by **Mordoch** » 28 Sep 2006, 23:25

ElcoB wrote:
bits44 wrote:JAA,FAA, and Airbus have concluded wake study, and have recommended additional spacing.
Ah yes; but only for following aircraft on approach and landing.

In spite of the way Airbus may have tried to spin the other component as a positive, it was expected that the recommendations would only involve additional spacing for following aircraft in the first place.

Its good that it doesn't involve additional spacing on takeoffs as well, but this is still a very serious problem. Basically this takes away the advantage of the A380 over just using 744s at capacity constrained airports where the number of gates is not the issue. In fact, if the 747-8I doesn't end up with these same wake restrictions, it could end up clearly being the superior option for airports capacity constrained in this manner.

bits44 · Post by **bits44** » 28 Sep 2006, 23:36

Ah yes; but only for following aircraft on approach and landing.

Yes you have hit the nail on the head, approach and landing, nothing else really matters.

The cause for concern for airport's , FAA, JAA, and other regulators is exactly that, approach and landing spacing, the others are important to some degree, but don't really cause concern.

These recommendations may be changed as real world experience unfolds, and may be revised to extend or shorten the distance, but the starting point has been established.

You might note that the take-off spacing is the same as landing.
"Same radar spacing as for Approach / Landing
Or, for time based operations: Heavy = 2 minutes; Medium, Light = 3 minutes"

Safety is the issue, nothing else matters!

Ruscoe · Post by **Ruscoe** » 29 Sep 2006, 00:36

Just to clarify because i am a little confused.

Have I got this correct that both takeoffs and landings will have the same increased spacings, and that these are greater than the 747, but in cruise the same spacings will apply?

Also as a matter of interest and comparison does anyone know the spacing requirements for other large aircraft, eg Galaxy, Antonov's.

Thanks,

Ruscoe

bits44 · Post by **bits44** » 29 Sep 2006, 02:25

Have I got this correct that both takeoffs and landings will have the same increased spacings, and that these are greater than the 747, but in cruise the same spacings will apply?

You are correct, the recommendation for spacing applies to both arrivals and departures.

The reason the spacing during cruise is maintained is because the Aircraft is in a clean configuration, ie " no flaps " thus the turbulence is minimal.

Also remember this is still only a recommendation, and may be changed.

KT

DFW · Post by **DFW** » 29 Sep 2006, 06:21

Ruscoe wrote:Also as a matter of interest and comparison does anyone know the spacing requirements for other large aircraft, eg Galaxy, Antonov's.

I don't know the answer, but a C-5 Galaxy is not in the same class as a 747 or 380. I've seen it side by side with a 747, and the Galaxy is enormous, at least twice the volume. I've been told it can carry an entire regiment (about 1,500 soldiers) but I can't confirm that. Few airports can land a C-5 because of the required runway length, so it may not have occurred to anyone to specify spacing.

CX · Post by CX » 29 Sep 2006, 08:22

so the idea is to have a A380 following closely the tail of the plane in front during take off and save some time... 8)

A350XWB · Post by **A350XWB** » 29 Sep 2006, 08:55

Airbus A380 Wake Vortex Study Completed

The Steering Group comprised representatives from the Joint Aviation Authorities (JAA), Eurocontrol, US Federal Aviation Administration (FAA), and Airbus.

http://www.eads.com/web/lang/fr/1024/co ... 78522.html

earthman · Post by **earthman** » 29 Sep 2006, 11:32

Mind you, there are no restrictions for an A380 following any other plane, including another A380. If you have a big A380 hub, you just schedule them to all go one after another, and only the plane following the last A380 will have to wait. You can also just stick it behind, say, a 747, so it won't have to keep as much distance as other planes. With proper scheduling, this should prove to be a minimal problem.

CX · Post by CX » 29 Sep 2006, 12:47

earthman wrote:Mind you, there are no restrictions for an A380 following any other plane, including another A380. If you have a big A380 hub, you just schedule them to all go one after another, and only the plane following the last A380 will have to wait. You can also just stick it behind, say, a 747, so it won't have to keep as much distance as other planes. With proper scheduling, this should prove to be a minimal problem.

I think take off won't be much of an issue since an A380 can probably start taking off before a lifting off 777 in front is even lifted from the ground... But for landing, no way you can follow another plane in too close, i guess airports with dual runways will be fine though..

smokejumper · Post by **smokejumper** » 02 Oct 2006, 19:06

DFW wrote:
Ruscoe wrote:Also as a matter of interest and comparison does anyone know the spacing requirements for other large aircraft, eg Galaxy, Antonov's.
I don't know the answer, but a C-5 Galaxy is not in the same class as a 747 or 380. I've seen it side by side with a 747, and the Galaxy is enormous, at least twice the volume. I've been told it can carry an entire regiment (about 1,500 soldiers) but I can't confirm that. Few airports can land a C-5 because of the required runway length, so it may not have occurred to anyone to specify spacing.

Any airport that can handle a wide body commercial jet can handle a C-5 (A/B). The plane has a capacity of over 51,000 gallons of jet fuel (400,000 pounds) and a maximum TO weight of 769,000 Pounds (normal, and 840,000 pounds in wartime)

It''s runway requirement is about 11,000 feet (at max TO weight) and 4,900 feet for landing. These numbers are not all that extraordinary and fit in with other large aircraft.

bits44 · Post by **bits44** » 28 Nov 2006, 13:38

An interesting news item on wake turbulance:

http://tinyurl.com/y7emza