Armavia A320 turbulence at cruise, A380 wake

[noelbaba]

By Simon Hradecky, created Monday, Jan 12th 2009 14:38Z, last updated Monday, Jan 12th 2009 15:39Z

An Armavia Airbus A320-200, flight U8-968 from Sochi (Russia) to Yerevan (Armenia), was enroute about 30nm north of Tiblisi (Georgia), when the airplane encountered severe clear air turbulence, which caused the autopilot to disconnect and threw the airplane into steep banks three times. The crew managed to regain control of the airplane and completed the flight without further incident. No injuries have been reported.

Armavia reported, that their aircraft was cruising 1000 feet below an Emirates Airbus A380-800 registration A6-EDB flight EK-201 enroute from Dubai (United Arab Emirates) to New York,NY (USA) and suspects, that the turbulence was caused by wake vortices created by the A380.

[Paradise Lost]

Sounds quite probable...but Airbus won't like it!

[oo-mvp]

Hi

What is the wake turbulence seperation (arriving acft) medium - A380 when they are using the same RWY?


MANU

[Wiley]

One of Airbus' earlier promises re the 380 was that it would not require more separation for landing and departure than a 747 (and hence not slow down arrivals and departures at busy airfields).

Anyone reading a current Notam set for an airfield serving the A380 will see what credence regulators have given that assurance. 4NM separation traffic behind a widebody and 6NM for traffic behind a 380.

[The Snake]

"Sounds like a bag of sh*** to me."

Very confident reply Skipness One Echo. Why would you have reason not to believe the Armavia crew statement? It's not normal that you bank steeply 3x during cruise without control inputs.

An ATC plot could show where the A320 and A380 were flying at the moment.

[rubymurray]

Er, not quite a bag of sh**e mate, I've encountered this during the cruise too, 2000' below an A340 (we were in a 737-8), mod to severe turbulence, a/pilot kicked out, extreme banking, pretty scary stuff!

A quick call to atc allowed us a change in direction out of the wake, problem solved!

[FlyingTom]

I've flown at right angles 4000' beneath the course of an A380 on test so probably light, and had severe turbulence. There is definately something different about the A380's wake.

[harmio]

Hi there,
First of all I just want to say i'm not a pilot, but I am really happy to have found a forum where I can actually talk to pilots! I think it's really amazing what you do..anyway...

I am an Armenian living in the UK, I was just watching the Armenian news here via satellite tv, and they were showing interviews with Armenian aviation specialists explaining how the event happened.

Basically they summised that they have written a letter to the relevant bodies (I'm sure you know better than me ) asking for the permissible distance between aircraft and A380 be increased , as this was the first recorded incident with the A380. From what I understand this is currently 330m, and thats exactly what the distance was between these aircraft...apparently.

Forgive me if my technical details are wrong, I have just translated as well as I could what I heard. I am just wondering, do you agree with this as pilots? It is interesting as Armavia have already had a problem with the Sochi Yerevan crash last year, I guess they are really trying to restore public faith in their safety record! Does any blame lie with Armavia here? They were saying on the news that the pilot did well to recover the situation ..but then they would say that,

Just wanted to hear your opinions.Regards

[noelbaba]

Mexico City Learjet Crash . . .
29:50.383 RADIO TWR MEX: Costera two five one five right twenty one cero terrestre
CAM: Unintelligible background noise, similar to conversation voices
29:53.929 RADIO: SLI 2515 right and golf, twenty one zero costera two five one five good day
29:59.32 CAM: Sound similar to background voices and laughter
29:57.28 Sounds similar to clap, clap, clap
29:58.059 PILOT: Holly! the turbulence from that one!
29:59.59 COPILOT: Wow dude.
29.59.716 Sound similar to tr, tr, tr
29.59.43 Sound similar to autopilot disconnection (normal when it's disconnected by one of the pilots)
29.59.44 PILOT: Ow, son-of-a-**** (Expression that denotes great effort)
30.00.00 CAM: what happened Moti?
30:02.250 COPILOT: Ow son-of-a-**** (Expression that denotes great effort)
30:02.50 PILOT: Ow, ow ...
30:03.016 PILOT: Alvaro, what do we do, Alvaro? (Expression that denotes great effort)
30:03.598 COPILOT: unintelligible (denoting great effort)
30:03.598 CAM: unintelligible voices denoting great effort
30:04.472 CAM: Sound similar to the altitud alarm
30:04.473 RADIO1 TWR MEX: Mexicana 845 authorized (unintelligle) left wind calm
30:05.586 COPILOT: Give it to me (Let me have it), Give it to me, Give it to me, Give it to me (Reflecting authority)
30:05.586 PILOT: Yours Alvaro (Apparently transferring control to the other pilot).
30:08.307 with calm wind authorized 5 Left
30:10.397 (Apparently the pilot): Son of a f*** b**** (Expression that denotes great effort)
30:10.397 (Apparently the pilot): Nooooo, Alvaro!
30:10.399 CAM Sound similar to altitud alarm
30:11.272 CAM: GPWS Terrain, terrain
30:11.350 (Apparently the copilot): My God.
30:12.600 CAM: Screams

In the original Spanish it's pretty clear they had found some "unexpected" hell of a turbulence they tried to fight with basically no success. It is also a bit more clear they perhaps they weren't too sure how to overcome the situation as they didn't have that much experience in the particular type, as reported by the investigation authorities that analyzed the CVR and FDR.

[Just wondering]

Hit some interesting wake descending through 27,000 into LHR the other day - found out a bit later the aircraft ahead was a 380. Later taken through the LOC as ATC were concerned about the spacing for wake - think, from memory, we were about 7 behind but ATC wanted us to have more

[ankh]

Does any routine testing of new aircraft include putting smoke into the wake to get a good idea of what kind of wake that new design produces?

[subsonic69]

Unfortunately no.. Most of the testing using this method are only done inside wind tunnels. Their main priority are vortices (for fuel efficiency) :} and very minimal to the wake that the aircraft produces. Most wake distance guidelines are calculated estimates since wind conditions can come from different directions.

Well in this case, since most pilots are experiencing wake turbulence even at the set distance from the double decker. I do hope somebody (or an authority would make an inquiry about this and hope that no accidents happen before they can set up some new guidelines.:ouch:

[Iolar]

LIDAR Wake turbulence measurements for the A380 were carried out at Oberpfaffenhofen, and in cruise, by DLR in summer 2006, a Lufthansa 747 was involved in the same program for direct comparisons.

From Airbus:

Airbus A380 Wake Vortex study completed
28 September 2006

Following three years of exhaustive studies, the Airbus A380 Wake Vortex Steering Group has rendered its conclusions and is now in a position to recommend more specific guidance, based on a unique and very extensive flight test programme. The Steering Group comprised representatives from the Joint Aviation Authorities (JAA), Eurocontrol, US Federal Aviation Administration (FAA), and Airbus.

The study has demonstrated that en route the A380 is very similar to the Boeing 747. In cruise and when flying in a "holding pattern", the A380 is considered to be identical to any other aircraft, both for vertical and horizontal spacing between it and any following aircraft.

The study has also established that there are no wake constraints for the A380 following any other aircraft, including another A380.

On approach, the spacing for the following aircraft is increased compared with the existing separation rules for aircraft currently in service, by two nm for another "heavy", by three nm for a “medium” sized aircraft, and by four nm for a "light" aircraft. However, because there are no constraints for the A380 following another aircraft, the A380 can land as close as practicable to the preceding aircraft. This can compensate for the additional spacing required for the following one.

On departures, a "heavy" aircraft following the A380 will have to wait two minutes, and the "medium" sized and "light" aircraft will have to wait three minutes. But here again, the A380 can take-off as close as possible to any preceding airliner. (See details in table below)

Though not specifically addressed, flight tests provided no indication of impact on parallel runway operations for runways separated by more than 760 m (2500 ft). This should be monitored in operational service for verification

These values are subject to review and possible reduction based on further study or changes in aircraft categories and operational experience. A significant aspect of this new guidance is that it has revealed the need for a future review of the existing aircraft categories, also taking into account operational experience.

The study was initiated in June 2003 with the objective of conducting investigations and gathering data to support recommendations, which would be made to the International Civil Aviation Organization (ICAO), regarding safe wake vortex separation criteria for aircraft following an A380 for various flight conditions.

The detailed scientific work was conducted by a subgroup consisting of the majority of the leading international experts in this complex field. It was supported by an unprecedented programme of flight tests with innovative aspects such as back to back comparative testing of different aircraft, cruise wake encounter tests, and ground and airborne LIDAR wake measurements, totalling over 180 hours flight time.

As an interim measure, pending completion of the scientific work, temporary guidance material was recommended to ICAO in 2005, to enable ICAO Member States to safely accommodate, from an air traffic management aspect, the A380 during its worldwide developmental flights. This interim guidance was necessarily conservative because data collection, processing, and analysis were still ongoing at that time.

Note to the editors:

Details of the key elements of the guidance for ICAO Heavy, Medium, and Light aircraft categories:

Vertical Spacing
Vertical spacing in all cases to be the same as for other aircraft

Evidence and data from encounter flight tests at cruise altitude, supported by airborne LIDAR measurements, have demonstrated that the A380 wake characteristics are equivalent to those of the B744 (chosen as the benchmark aircraft) for this phase of flight. Therefore, the current ICAO vertical separations are confirmed to be appropriate for A380 operations.

Horizontal spacing en-route
En-route horizontal spacing to be the same as for other aircraft

Holding
Vertical spacing to be the same as for other aircraft

Approach / Landing
No wake constraint for the A380 as a following aircraft
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)

Departure following A380
No wake constraint for the A380 as a following aircraft.
Same radar spacing as for Approach / Landing
Or, for time based operations: Heavy = 2 minutes; Medium, Light = 3 minutes

[dvv]

The news blurb says the A320 was thrown into a left roll, which makes me think — somebody was tracking to the right of the centerline…

[FlyingChipmunk]

About 6 weeks ago one of our company Saabs lost control on final approach into Sydney on Rwy34R. It landed okay without a G/A required.....great piloting.

On simultaneous final was an A380 and there was a strong westerly, which carried most of the wake into the path of the Saab.

Studies are now furiously being undertaken by the ATSB and during the interim, its really "buyers beware", every man for himself. Stay above the glidepath if possible and manage your own wake separation. Sydney ATC have also been really helpful.

We get 3 x A380s almost daily in Sydney, and at this stage, everybody is quite aware of the pitfalls of ignorance......:\

[dany4kin]

YouTube - A380 Wake Turbulence (http://uk.youtube.com/watch?v=__pyxPb6gMc)

Gets interesting about half way through.

YouTube - Estela de turbulencia generada por un C-5A Galaxy (http://uk.youtube.com/watch?v=78FVu3_PBpU)

An old test but still quite interesting.

[Put1992]

YouTube - A380 Wake Turbulence (http://uk.youtube.com/watch?v=__pyxPb6gMc)

Gets interesting about half way through.

Interesting how they didn't repeat the test with the aditional wingtips

[SLF3b]

I understood the A380 was supposed to increase the throughput of congested airports like Heathrow by increasing the pax load per flight. If I read the above correctly, in the real world the additional time between departures effectively negates this advantage, and on arrivals means there is little real benefit.

Am I reading the Airbus report correctly?

[lomapaseo]

I find the discussion on wake turbulence interesting and only wish it had its own separate thread.

I'm not willing to link the A380 flight with the reported incident yet and would like more discussion and facts along this line.

Just how close did these two aircraft come and over what time frame.

Is there any kind of 3D graphics of this?

[BladePilot]

Watched the A380 test bed aircraft (frame number 3 I think, maybe wrong) performing at the Dubai Airshow in Emirates colours before first delivery (Dec 2005 I think, have a memory like a sieve!). We were permitted out as far as the edge of the ramp adjoining the Exhibition Centre at DXB way out beyond the static aircraft display. It was the first time I'd seen the beast fly and I was amazed at how quiet the aircraft was as it gathered momentum on its take off roll. The weather was beautiful and we had a very light warm breeze in our faces as we watched the aircraft silently roll past us. As we watched the nosewheel slowly lift we were hit full on by what I can only describe as a ferocious gust of wind so strong I had to actually lean into it to avoid taking a step back I watched in amusement as folks scambled to hold onto hats, coats and anything else which may have been parted from them by the sudden gust, its was particularly amusing watching the ladies bravely attempt to defend their dignity:)
I recall turning to a colleague and saying 'they'll have a job convincing the authorities that that thing has anywhere near the same wake turbulence characteristics of a 747':eek:

Stand Well Clear!

http://www.flightglobal.com/articles/2008/11/07/318553/a380-wake-no-worse-than-any-other-heavy-jet-airbus.html

[VONKLUFFEN]

Iolar got it correct. 3 minutes separation between 380 and medium during landing and take off. Find it in the AERED ( it only mentions T/O )

During cruising is something completely different. It is hard to tell when and where the wake will hit , but have in mind that with RVSM levels and with no lateral wind blowing most certainly you might hit the wake.
Last but not least , the phenomena is much more severe during cruise due to the fact of speed. 160 knots are not the same as M.84

[Iolar]

On a side note, there's an interesting article in the latest edition of the Eurocontrol Experimental Center Newsletter from autumn 2008. The article concerns a redefinition of the Heavy, Medium and Light categories (RECAT). As far as I understand the idea is that presently those aircraft on the boundaries of the present categories could be included in new categories (by subdividing the existing ones) relaxing separation requirements and increasing capacity.

EUROCONTROL - Revising wake turbulence categories to gain capacity (RECAT) (http://www.eurocontrol.int/eec/public/standard_page/EEC_News_2008_3_RECAT.html)

[harrogate]

About 6 weeks ago one of our company Saabs lost control on final approach into Sydney on Rwy34R. It landed okay without a G/A required.....great piloting.

On simultaneous final was an A380 and there was a strong westerly, which carried most of the wake into the path of the Saab.

Studies are now furiously being undertaken by the ATSB and during the interim, its really "buyers beware", every man for himself. Stay above the glidepath if possible and manage your own wake separation. Sydney ATC have also been really helpful.

We get 3 x A380s almost daily in Sydney, and at this stage, everybody is quite aware of the pitfalls of ignorance.....

Interesting point that, because a very similar point was raised as a safety conern on the radio the other day by a member of the anti third runway lobby at Heathrow (an ex airman, I believe).

3 parallel runways over densely populated areas, and a heady mixture of aircraft of all sizes. Folks on here will no doubt point out the differences between LHY and SYD, but to the lay gutter hack it's far more black and white - Heathrow, in their eyes, will be an accident waiting to happen.

[Chesty Morgan]

Last but not least , the phenomena is much more severe during cruise due to the fact of speed. 160 knots are not the same as M.84

Err, nope. Reverese that!

[lomapaseo]

Err, nope. Reverese that!

Why's that:confused:

Is it because of dirty vs cling wing?

[India Four Two]

http://www.faa.gov/airports_airtraffic/air_traffic/publications/ATPubs/AIM/Chap7/aim0703.html
7-3-3. Vortex Strength
a. The strength of the vortex is governed by the weight, speed, and shape of the wing of the generating aircraft. The vortex characteristics of any given aircraft can also be changed by extension of flaps or other wing configuring devices as well as by change in speed. However, as the basic factor is weight, the vortex strength increases proportionately. Peak vortex tangential speeds exceeding 300 feet per second have been recorded. The greatest vortex strength occurs when the generating aircraft is HEAVY, CLEAN, and SLOW.

[kokako7]

Hi!
Actually this incident happaned in my airspace and investigation is still in progress. What can I say at this stage, is that there were no reports from the pilot of armavia of any turbulence. It's some kind of strange when he said about that when he landed in armenia.
I'll brief you more as soon as I get more info;)

[Chesty Morgan]

lomapaseo

Induced drag and its wing tip vortices are a created as a wing produces lift. The Coefficient of Lift increases as the Angle of Attack is increased.

Induced drag is inversely proportional to the square of the speed whereas all other drag is directly proportional to the square of the speed.

The effect of this is that induced drag is relatively unimportant at high speed in the cruise and descent where it probably represents less than 10% of total drag.

At low speeds, just after take off, in the initial climb and the final approach it can produce up to 70% of the total drag.

[Awl flyer]

Hi folks
The same occurrence experienced on B732 almost one year ago, (night flying, clear sky, winter time, daytime warming over the mountains, in my case) makes me to believe that it’s just something that concerns to the weather phenomenon over the flying route rather than A380 related incidence like, but who knows…it’s enormous not to make a sever turbulence pilot report in the air, what ever the case. 100% agree with India 42 post.

[Ranger One]

About 6 weeks ago one of our company Saabs lost control on final approach into Sydney on Rwy34R. It landed okay without a G/A required.....great piloting.

This is an interesting and informative thread. But the above comment set me to thinking... if the approach was destablised to the extent that 'great piloting' was required in order to 'land okay', then perhaps the 'greater piloting' would have been to select the G/A in the first place...

[BladePilot]

Question to all the boffins and lift experts:

Surely the A380 wake characteristics are cause by the cord and camber of the wing and not by any significant increase in wingtip generated vortex? Begging the question; were promotional videos made by Airbus suggesting that the fitting of wingtip 'fences' to reduce the aircrafts wake turbulence signature just a red herring when all along they knew that the cord and camber of the wing generated wake turbulence characteristices quite unlike anything we'd seen before?

Viewed from behind it is clearly evident that the cord and camber of the wings is significantly different from any other commercial aircraft flying at the moment.
:confused:

[scrivenger]

Quote:
7-3-3. Vortex Strength
a. The strength of the vortex is governed by the weight, speed, and shape of the wing of the generating aircraft. The vortex characteristics of any given aircraft can also be changed by extension of flaps or other wing configuring devices as well as by change in speed. However, as the basic factor is weight, the vortex strength increases proportionately. Peak vortex tangential speeds exceeding 300 feet per second have been recorded. The greatest vortex strength occurs when the generating aircraft is HEAVY, CLEAN, and SLOW.

Significantly wind speed and direction will play its part. Consider for example an A380 on short finals with severe windshear to contend with too. Furthermore consider the vortex created if the aircraft encounters significant CAT. Does anybody have any data on these two scenarios for the 380?

[Super VC-10]

Do I understand from the above that an A380 could (in theory) take off immediately (under 1 min) after another A380 with no effect or worries about wake vortex?