A320 vortex generator retrofit

[underfire]

An interesting concept...

"JetBlue Airways, today announces plans to retrofit its entire Airbus fleet with noise-reducing vortex generators. This move reflects JetBlue’s continued commitment to the communities where its customers and crewmembers live and work. Beginning in 2015, JetBlue began taking delivery of new aircraft with vortex generators already installed. JetBlue is committing to add the devices to its 138 remaining Airbus A320 family aircraft through 2021. The small devices disrupt wind over ports on the wing which can produce a “whistling” tone during approach into an airport.

JetBlue is following the lead of Lufthansa."

Vortex generators will be installed on 130 existing JetBlue A320 aircraft and eight JetBlue A321 aircraft during their existing scheduled heavy checks with the full fleet wide install expected to be complete in 2021. All future Airbus orders will be delivered with vortex generators already installed"

https://cimg7.ibsrv.net/gimg/pprune.org-vbulletin/600x109/lufthansa_sound_reducing_vortex_generators_7fa532a95c8732e06 21ea0407f6d4ff7edf2d718.jpg

https://cimg1.ibsrv.net/gimg/pprune.org-vbulletin/625x227/screen_shot_2018_10_10_at_2_32_07_pm_167072f694d0a28173418da f53f5500bae2447d2.png

There was the 320 howler, didnt hear about the whistler....

[Dan Winterland]

These are the holes which house the fuel tank overpressure ventilation burst discs. I didn't know they made a whistling sound. But then again, an A320 rarely flies over my head on approach.

[TURIN]

I think they all have them now. Certainly all the ones I see in the UK.

[Denti]

The new ones since the introduction of the sharklets (roughly around that time) had those vortex generators, but i noticed that some airlines seem to have retrofitted them on their older ones as well, a large orange one in europe seems to have done that already, but i could be wrong.

[FlightDetent]

What is the business case?

[DaveReidUK]

What is the business case?

Good neighbourliness/PR.

Different airlines will place a different value on that, which is why some (most?) have retrofitted the mod and others haven't (yet).

[FlightDetent]

Dave, I do not believe for a second that's how it works. Once installed, it is immediately used for PR selling the good neighborliness factor, yes. Absolutely no issues with that but it does not quench my curiosity.

The costs of certifying an element protruding into the airflow on a wing are huge, and somebody needs to pay for that. Especially if we both guess most will buy it there needs to be a widely applicable positive ROI somewhere. Going one step deeper, the ROI (and a profit margin on top) had surely been identified before authorizing the development of the gadget in the first place.

I am thinking of regulatory compliance with future noise limitations, and wonder what the fuel impact is over a year's worth of flying. That needs to be offset too.

EDIT: silently hoping to be wrong...

[DaveReidUK]

The costs of certifying an element protruding into the airflow on a wing are huge, and somebody needs to pay for that. Especially if we both guess most will buy it there needs to be a widely applicable positive ROI somewhere. Going one step deeper, the ROI (and a profit margin on top) had surely been identified before authorizing the development of the gadget in the first place.

I'm not disputing that for a moment. Airbus certainly won't be giving away the mod kits for free, there will have been a bean-counter involved at some stage.

[Denti]

I believe Lufthansa developed the fix on its own, got it certified and then shared it with Airbus. Lufthansa has some very problematic neighbour relationship at its main hub in Frankfurt, so much so that there is an anti-noise demonstration every Monday evening in the mainly Lufthansa used Terminal 1 of the airport. Every little bit that could seen as helping is therefore welcome. As there is of course some intellectual property rights attached to that fix, Lufthansa could actually earn from every installation as well, which would be a very nice business case in itself, not to mention that they do obviously sell maintenance support, flight planning and charting software as well as crew planning solutions...

[FlightDetent]

:ok: That is a nice 360 solution for Lufty then, well done smart people. Thanks.

Though I still have the mirage of a sales presentation with the regulatory bit in it. Or was it a Flight International article a few years back, when the flight tests started?

[Auxtank]

I believe Lufthansa developed the fix on its own, got it certified and then shared it with Airbus.

Yes, that's correct. Lufthansa only and ever develop/ push for technical upheavals because they they have ascertained (usually on their own) that it is as a profitable modification to the airframe. In that respect they are pioneers and have always been.

[underfire]

Airbus certainly won't be giving away the mod kits for free, there will have been a bean-counter involved at some stage.

"Vortex generators will be installed on 130 existing JetBlue A320 aircraft and eight JetBlue A321 aircraft during their existing scheduled heavy checks with the full fleet wide install expected to be complete in 2021. All future Airbus orders will be delivered with vortex generators already installed. The cost to retrofit the full Airbus fleet is less than $1 million."

https://www.businesswire.com/news/home/20181010005816/en/JetBlue-Retrofit-Airbus-Fleet-Vortex-Generators

[Down Three Greens]

Gatwick will be charging more airbus aircraft not fitted with the FOPP mod. That factors into the business case.

a320 Whine (http://a320whine.com/)

https://www.gatwickairport.com/globalassets/publicationfiles/business_and_community/all_public_publications/2017/2017-18-conditions-of-use---final---sent-30jan17.pdf

page 15

[Denti]

Gatwick will be charging more airbus aircraft not fitted with the FOPP mod. That factors into the business case.

Thanks, that explains why the orange cult has been installing them. With the numbers of aircraft they have based in Gatwick it is a very clear business case then.

[DaveReidUK]

"Vortex generators will be installed on 130 existing JetBlue A320 aircraft and eight JetBlue A321 aircraft during their existing scheduled heavy checks with the full fleet wide install expected to be complete in 2021. All future Airbus orders will be delivered with vortex generators already installed. The cost to retrofit the full Airbus fleet is less than $1 million."

Thanks for that. So it sounds like the cost to the operator of embodying the mod is around $7,000 per shipset.

[FlightDetent]

https://www.gatwickairport.com/globalassets/publicationfiles/business_and_community/all_public_publications/2017/2017-18-conditions-of-use---final---sent-30jan17.pdf Page 27: penalty of 1500/2000 GBP per visit, yikes!! :eek:

[RIN67630]

Dave, I do not believe for a second that's how it works. Once installed, it is immediately used for PR selling the good neighborliness factor, yes. Absolutely no issues with that but it does not quench my curiosity.
The costs of certifying an element protruding into the airflow on a wing are huge, and somebody needs to pay for that. Especially if we both guess most will buy it there needs to be a widely applicable positive ROI somewhere. Going one step deeper, the ROI (and a profit margin on top) had surely been identified before authorizing the development of the gadget in the first place.
I am thinking of regulatory compliance with future noise limitations, and wonder what the fuel impact is over a year's worth of flying. That needs to be offset too.
EDIT: silently hoping to be wrong...

I can reassure you: you are wrong! I am well informed on that topic.
No regulatory compliance with future noise limitations are involved: the A32 whine effect does not happen a the certification points.
The technical mod costs 3000$ (Source: Airbus)
The certification cost have been taken over by Airbus. The fuel impact has been computed to be slightly... positive by DLR, who developed the solution.
Lufthansa just contributed slightly upon testing.
The business model might be a bit PR, although I do not either believe for a second that any neighborliness goodwill might ever exist in an airline manager thoughts.

The business model dirty simple: More and more airports are providing a bonus on landing fees to retrofitted planes. Even with a slight fee reduction of only 10$ per operation, the ROI is less than a year.
This is an extremely profitable investment.

Regards

[FlightDetent]

That is very good and pleasant to hear! People doing the right things for the right reasons.

[underfire]

The fuel impact has been computed to be slightly... positive by DLR, who developed the solution.

A fuel impact due to a vortex generator over a small opening on the wing???

Just think if they covered the landing gear! :ok:

[alexh1987]

We (Lufthansa-group airline) have installed them on all our A320 and as someone who lives directly under the approach path of a nearby airport I can tell you that these vortex generators really make a difference. The whisteling noise is completely gone after the modification.

[IFixPlanes]

Soundsamples:
https://www.lufthansagroup.com/en/responsibility/climate-environment/active-noise-abatement.html

[underfire]

Nice! Thank you!

[CaptainMongo]

Soundsamples:
https://www.lufthansagroup.com/en/responsibility/climate-environment/active-noise-abatement.html


yes, thank you very much - oder, Vielen dank!

[RIN67630]

We (Lufthansa-group airline) have installed them on all our A320 and as someone who lives directly under the approach path of a nearby airport I can tell you that these vortex generators really make a difference. The whisteling noise is completely gone after the modification.


Oh yes, the noise relief is now 6dB at least, that means that the noise energy produced is now divided by 4.
In other words, proviously the silly A320's FOPs emitted 3 times more noise than all the rest of the plane!
:eek:

[RIN67630]

A fuel impact due to a vortex generator over a small opening on the wing???
Just think if they covered the landing gear! :ok:

It was the concern of FlightDetent that the small vortex gens could have a negative impact on the fuel consumption.
The landing gears can be retracted.

Pilots can however remember that outputting the landing gears too early costs fuel and increases the residential noise.
Regards.
Laszlo

[RIN67630]

That is very good and pleasant to hear! People doing the right things for the right reasons.

Yes. Unfortunately many planes from Eurowings taken over from Air Berlin are still not retrofitted. Their managers seem to be unable to calculate.

[tdracer]

On the original pure turbojet and low bypass turbofan jets, the engine noise so dominated the noise generation that nobody paid much attention to the aerodynamic noise generation. But as the engines have gotten progressively quieter, the airframe contribution has become increasingly important. Years ago Boeing did a noise test of the 747 (I forget which model but is was long enough ago that I suspect it was a -200). They flew over the microphone array at max takeoff power, then repeated the tests - same speed, altitude, etc. but with the engines at idle. It only made 3 db difference - basically meaning that at takeoff power the airframe contribution to the noise was roughly equal to the engines :eek:
On the new, quieter aircraft (787, 747-8, A350, etc) the noise engineers spend as much time working things like the flaps and landing gear as they do the engines.

[RIN67630]

On the original pure turbojet and low bypass turbofan jets, the engine noise so dominated the noise generation that nobody paid much attention to the aerodynamic noise generation. But as the engines have gotten progressively quieter, the airframe contribution has become increasingly important. Years ago Boeing did a noise test of the 747 (I forget which model but is was long enough ago that I suspect it was a -200). They flew over the microphone array at max takeoff power, then repeated the tests - same speed, altitude, etc. but with the engines at idle. It only made 3 db difference - basically meaning that at takeoff power the airframe contribution to the noise was roughly equal to the engines :eek:
On the new, quieter aircraft (787, 747-8, A350, etc) the noise engineers spend as much time working things like the flaps and landing gear as they do the engines.

I m not surprised. The engines ususally radiate noise behind the aircraft.The noise intensity with hen engines on might make only 3dB difference, the duration is however longer. But for the certification tests the duration was not relevant.
One frequently forget, that landings harms more people than starts. Landing is flat and aircrafts follow the ILS as on rails. The starts are steeper and the routes diverge soon.
And yes some trivial improvements like castellated bolts on the wheels make a significant difference on the landing noise.

[underfire]

The landing gears can be retracted.

I was referring to the variants where, when retracted, the landing gear is not covered. I would think that castellated bolts would make more noise?
https://cimg5.ibsrv.net/gimg/pprune.org-vbulletin/768x890/wheel_f3b12d10cf551e712718ae902ceeb7c39c0693eb.jpg


https://cimg8.ibsrv.net/gimg/pprune.org-vbulletin/1024x788/16430l_bf08c5169cfa18c849bb1ec7fb5e958ac7637c88.jpg

[jimjim1]

Gatwick will be charging more airbus aircraft not fitted with the FOPP mod. That factors into the business case.
https://www.gatwickairport.com/globalassets/publicationfiles/business_and_community/all_public_publications/2017/2017-18-conditions-of-use---final---sent-30jan17.pdf

Charges seem not insignificant. Page 27 (as printed on bottom of page). I don't know what "chapter" the A320 is in. Text is all legible here if page full screen.

https://cimg1.ibsrv.net/gimg/pprune.org-vbulletin/718x370/a320_noise_1d74a2eabfca66baa61886087fc820e76d8289ea.png

[underfire]

I think the unmodified A320 family sums it up

As part of the wake turbulence measurement, we are measuring the sound frequency of the passing ac, not just the noise level. This helps in the mitigation of noise, as a blanket insulation is overkill, but if you target frequencies, the mitigation can be very effective.

[DaveReidUK]

I don't know what "chapter" the A320 is in.

Chapter 4.

[RIN67630]

I think the unmodified A320 family sums it up<br />As part of the wake turbulence measurement, we are measuring the sound frequency of the passing ac, not just the noise level. This helps in the mitigation of noise, as a blanket insulation is overkill, but if you target frequencies, the mitigation can be very effective.<br /><br />

I have a detailed frequency diagram for you: The frequency analysis there (Sonogramm) reveals a lot: the whine sound (the pair of Z shaped dark traces) is perceived far before and long after the main aircraft noise.<br />The unmodified A320 is an acoustical catastrophe in the begin of the ILS landing.<br />
Since i can't post an image yet, I invite you to go to cjoint.com and append /doc/18_11/HKxvmhuM0d1_Akustische-Analyse.jpg to that address.
Maybe someone can post the image for me?
Regards
Laszlo

[waito]

Never found the reason until now. The ugly disgraceful whine sound of A320 family. Only at landing. But not anymore before touchdown. Thanks a bunch they found a solution. Unfortunately still some aren't fixed.

The poster above mentioned diagrams. I share them. The frequencies of those different sized openings are stated as 530Hz and 580Hz. Absolutely disharmonic and annoying, See here the recording of an A320 overfly. Sonogram: Left to right is approaching over leaving the microphone position. More black means higher noise level. See the 2 strong curves, that's the dominating whine sound. And it is the first noise one hears and the last before the noise disappears. Due to doppler effect the frequency lowers during overpass.

https://cimg6.ibsrv.net/gimg/pprune.org-vbulletin/368x570/airbuswhine1_3a71bcc87f32960e7866dc1e97a2e19f6228c712.jpg
https://cimg9.ibsrv.net/gimg/pprune.org-vbulletin/1232x755/airbuswhine2_037bf8c2a5aa60f112036f61a1df3ef351dcfbe6.jpg

[waito]

Oh, this is a good overview
Presentation re EasyJet (gatwickairport.com; PDF) (https://www.gatwickairport.com/globalassets/publicationfiles/business_and_community/all_public_publications/aircraft_noise/arrivals-review/gal-noise-presentation-26th-april-2016---ezy-for-web.pdf)

[FlightDetent]

Further search in the old threads reveals your annoyance well share around the globe. At one point, probably even still, Gatwick Airport would charge what, 900 GBP if you'd brought in aircraft without the MOD? Per movement! The answer probably in the AIP.

[waito]

Gatwick Airport would charge what, 900 GBP if you'd brought in aircraft without the MOD? Per movement! The answer probably in the AIP.

Obviously such was necessary to force the airlines into action. Well done, Gatwick! If some other relevant airports follow, healing is ahead. I mean, the A320 family, compared to recent other traffic on approach, was outstanding in noise and how it bothers your brain.

[FlightDetent]

Sorry for the grammar of the previous post. More soothing reading here: https://www.gatwickairport.com/globalassets/business--community/new-sub-category-landing-pages/aircraft-noise--airspace/fpt-reports/gal-end-noise-action-plan-2019-2024-lr.pdf Slide 45 shows a daytime turn-around with an A320 without the generators incurs a penalty of 1400 GBP. That's actually more of a political statement than a fee, not joking.