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A320 Whine On Approach  
User currently offlineDocLightning From United States of America, joined Nov 2005, 20362 posts, RR: 59
Posted (2 years 4 months 2 weeks 2 days 21 hours ago) and read 10886 times:

I have noticed that I can very easily ID A320-series aircraft when they are on final approach by sound alone. They make a strange "harmonic" whining noise as they pass overhead. No other aircraft makes this noise on approach.

The noise is made by all A320-series aircraft to my knowledge, regardless of engine option. I have never heard it on climb-out.

Is it made by a certain flaps setting? Does anyone know?

26 replies: All unread, showing first 25:
 
User currently offlineN243NW From United States of America, joined Jul 2003, 1640 posts, RR: 20
Reply 1, posted (2 years 4 months 2 weeks 2 days 20 hours ago) and read 10862 times:

I have also heard the same sound - it definitely seems to be more of an aerodynamic warble than an engine noise. My initial impression would be flaps as well.


B-52s don't take off. They scare the ground away.
User currently offlineAA737-823 From United States of America, joined Mar 2000, 5947 posts, RR: 11
Reply 2, posted (2 years 4 months 2 weeks 2 days 4 hours ago) and read 10629 times:

You're not going to believe this, but I actually think it's the underwing retractable landing lights.
AND (see? I have something to backup my opinion!) I think this because when I fly on A320s, I can hear the landing lights being extended on final. And they make a distinct noise. You can easily tell when they're on, particularly on approaches at night, because you can see the light reflecting on the cowl.

And it makes a distinct aerodynamic noise.

The 737NG has a similar design for retractable lights, but they're mounted to the fuselage belly, rather than under the wing in the wing-body fairing area. And I don't hear it on a 737 like I do an A320.


So, I've noticed it too, and I'm sticking to my guns- I think it's the extended landing lights.


User currently offlinezeke From Hong Kong, joined Dec 2006, 9240 posts, RR: 76
Reply 3, posted (2 years 4 months 2 weeks 2 days 4 hours ago) and read 10621 times:

I think the higher frequency sound heard as the aircraft approaches is a Doppler effect from the engines.


We are addicted to our thoughts. We cannot change anything if we cannot change our thinking – Santosh Kalwar
User currently offlinecaptainmeeerkat From Russia, joined Aug 2010, 398 posts, RR: 1
Reply 4, posted (2 years 4 months 2 weeks 1 day 22 hours ago) and read 10479 times:

Quoting AA737-823 (Reply 2):
I think this because when I fly on A320s, I can hear the landing lights being extended on final. And they make a distinct noise.

That is very true, I have noticed that too. I am always listening for the noises of flaps, gear etc and this one confused me a little until I figured it out. It certainly changes the noise inside the cabin..



my luggage is better travelled than me!
User currently offlinee38 From United States of America, joined May 2008, 370 posts, RR: 0
Reply 5, posted (2 years 4 months 2 weeks 1 day 15 hours ago) and read 10328 times:

Quoting AA737-823 (Reply 2), "when I fly on A320s, I can hear the landing lights being extended on final."

I'm not familiar with procedures at other carriers, but at Delta, on the A-320/A-319 fleet, the landing lights are extended as the aircraft descends through 10,000 feet AGL. This is to increase aircraft visibility in the low altitude environment. Therefore, the landing lights are on well before the aircraft is on final approach.

Similarly, the landing lights normally remain on until climbing through 10,000 feet AGL.

e38


User currently offlineB747forever From Sweden, joined May 2007, 17149 posts, RR: 10
Reply 6, posted (2 years 4 months 2 weeks 1 day 14 hours ago) and read 10307 times:

Quoting e38 (Reply 5):
I'm not familiar with procedures at other carriers, but at Delta, on the A-320/A-319 fleet, the landing lights are extended as the aircraft descends through 10,000 feet AGL. This is to increase aircraft visibility in the low altitude environment. Therefore, the landing lights are on well before the aircraft is on final approach.

Similarly, the landing lights normally remain on until climbing through 10,000 feet AGL.

Isnt that mandatory for all operating aircraft around the world?



Work Hard, Fly Right
User currently offlineDocLightning From United States of America, joined Nov 2005, 20362 posts, RR: 59
Reply 7, posted (2 years 4 months 2 weeks 1 day 10 hours ago) and read 10250 times:

Quoting e38 (Reply 5):
I'm not familiar with procedures at other carriers, but at Delta, on the A-320/A-319 fleet, the landing lights are extended as the aircraft descends through 10,000 feet AGL. This is to increase aircraft visibility in the low altitude environment. Therefore, the landing lights are on well before the aircraft is on final approach.

I have heard this noise well before final approach. Today I was under the approach path for SFO and I noticed a few things. 1) Yes, only A320's make this noise. 2) It starts very suddenly. You can hear the lights (assuming that's what makes the noise) extending.

I also spent some time under the departure path and I hear the same noise (a few miles away from the airport... about five miles north, actually), which I hadn't noticed before.


User currently offlineLH707330 From United States of America, joined Jun 2012, 849 posts, RR: 0
Reply 8, posted (2 years 4 months 2 weeks 20 hours ago) and read 10074 times:

Quoting DocLightning (Thread starter):
The noise is made by all A320-series aircraft to my knowledge, regardless of engine option.

True, but the CFMs can be heard under that whine more so than the IAEs can, which leads me to suspect that the landing-light theory is a good one because the nacelles are different.


User currently offlinelonghauler From Canada, joined Mar 2004, 5164 posts, RR: 43
Reply 9, posted (2 years 4 months 2 weeks 18 hours ago) and read 10038 times:

The landing lights would be extended well before approach. It would be more than 30 miles out, descending through 10,000 feet, as noted above.

Their noise is distinct and certainly noticeable, but it is more of a "rumble" from the disturbed airflow than a "whine".

Quoting LH707330 (Reply 8):
which leads me to suspect that the landing-light theory is a good one because the nacelles are different.

Except that the extendable landing lights are not near the nacelles. If the whine is more noticeable on the CFMs than the IAEs then likely it is engine fan harmonics.



Never gonna grow up, never gonna slow down .... Barefoot Blue Jean Night
User currently offlineLH707330 From United States of America, joined Jun 2012, 849 posts, RR: 0
Reply 10, posted (2 years 4 months 2 weeks 17 hours ago) and read 10005 times:

Quoting longhauler (Reply 9):
Except that the extendable landing lights are not near the nacelles. If the whine is more noticeable on the CFMs than the IAEs then likely it is engine fan harmonics.

Maybe the engines just sound different and the IAE sounds closer to the whine, because they both have it but the CFM you can also hear a bit of jet noise.


User currently offlineDocLightning From United States of America, joined Nov 2005, 20362 posts, RR: 59
Reply 11, posted (2 years 4 months 2 weeks 16 hours ago) and read 9981 times:

Quoting longhauler (Reply 9):
Except that the extendable landing lights are not near the nacelles. If the whine is more noticeable on the CFMs than the IAEs then likely it is engine fan harmonics.

I have noticed that VX's A320's (CFM) make the exact same noise as UA's (IAE).


User currently offlineAmericanB763ER From Luxembourg, joined Sep 2005, 166 posts, RR: 0
Reply 12, posted (2 years 4 months 2 weeks 8 hours ago) and read 9899 times:

It's amazing how 2 different engine types can sound so similiar - at least on approach - otoh it makes it almost impossible to tell the CFMs from the IAEs on an approaching A32X; but the good thing is you don't even have to crane your neck to identify the aircraft.

I wonder what it is exactly that makes the -5A's on approach ring so differently from the other CFM56 - variants, and why the V2500 have almost the same sound signature - again on approach. I'm sure there is a technical explanation but I'm no expert alas...


User currently offlineB6JFKH81 From United States of America, joined Mar 2006, 2902 posts, RR: 7
Reply 13, posted (2 years 4 months 1 week 6 days ago) and read 9642 times:

Quoting longhauler (Reply 9):
Their noise is distinct and certainly noticeable, but it is more of a "rumble" from the disturbed airflow than a "whine".

Indeed, and it is quite noticeable if you are sitting overwing on an A320-series when they get extended. I also don't think the sound (I like to call it a UFO whine LOL) is attributed to the lights especially when its taken into consideration that other aircraft have lights like these and they don't have that whine (although the placement of these lights does vary).

The A320-series definitely has a distinct sound to it. I live out in West Babylon, Long Island. When the 22s are in use at JFK, there is a plane over my house every 2 minutes (sometimes less) at ~4000 - ~5000 feet as they make their way north from the ocean towards the northern part of LI before turning for the 22s (love it when the big boys fly over, always nice to see the A380, A346, B744   ). I can always tell when an A320-series is going overhead with that lovely "UFO whine" and it really does seem to be something more with the engine, possibly the fan blades. I do notice a bit of a difference though, the V2500 seems to be a little more on the quiet side as they go over, I'm thinking that may have to do with the C.N.A. on the that engine.



"If you do not learn from history, you are doomed to repeat it"
User currently offlineDocLightning From United States of America, joined Nov 2005, 20362 posts, RR: 59
Reply 14, posted (2 years 4 months 1 week 6 days ago) and read 9629 times:

Quoting B6JFKH81 (Reply 13):
I can always tell when an A320-series is going overhead with that lovely "UFO whine" and it really does seem to be something more with the engine, possibly the fan blades.

I guarantee it isn't, because on approach they don't make the noise and then suddenly there is a rumble like something being extended and then the noise starts.


User currently offlinelonghauler From Canada, joined Mar 2004, 5164 posts, RR: 43
Reply 15, posted (2 years 4 months 1 week 5 days 23 hours ago) and read 9613 times:

Quoting DocLightning (Reply 14):
I guarantee it isn't, because on approach they don't make the noise and then suddenly there is a rumble like something being extended and then the noise starts.

Okay, more to the puzzle.

Gear being extended? That certainly causes a lot of rumble.
Perhaps flaps being extended further?

Or it could be the resulting increase in engine noise with the extension of the above. Remember, the "A320 engine buzz" on take off is a result of high power combined with low speed. (I think it sounds like sitting between a pair of Evinrudes). But to a lesser extent than on take-off, with the extension of gear and flaps, the low speed/higher power occurs again.



Never gonna grow up, never gonna slow down .... Barefoot Blue Jean Night
User currently offlineB6JFKH81 From United States of America, joined Mar 2006, 2902 posts, RR: 7
Reply 16, posted (2 years 4 months 1 week 5 days 22 hours ago) and read 9582 times:

Quoting longhauler (Reply 15):
Gear being extended? That certainly causes a lot of rumble.
Perhaps flaps being extended further?

The "UFO whine" noise exists well before the gear gets extended as I hear it when they go over my house which is about 20 miles from JFK (as the crow flies) and aircraft still have quite a ways to go. Not sure what setting the flaps are at when they pass over though, my guess is minimal setting at best as I really don't see flaps get dropped until we are getting close to turning final (based on the flights I've been on).



"If you do not learn from history, you are doomed to repeat it"
User currently offlineWingedMigrator From United States of America, joined Oct 2005, 2260 posts, RR: 56
Reply 17, posted (2 years 4 months 1 week 5 days 20 hours ago) and read 9563 times:

Quoting B6JFKH81 (Reply 16):
The "UFO whine" noise exists well before the gear gets extended

   you are talking about the sudden-onset whine that drops rapidly in pitch and morphs into the regular sound of an airplane flying overhead, right?

Quoting DocLightning (Reply 7):
2) It starts very suddenly. You can hear the lights (assuming that's what makes the noise) extending.

It starts very suddenly, but it's probably not related to any deployment event because it always starts with the same angle between the plane of the fans and the line of sight of the observer. Try paying attention to that next time, and you'll hear/see what I mean.


User currently offlineAA737-823 From United States of America, joined Mar 2000, 5947 posts, RR: 11
Reply 18, posted (2 years 4 months 1 week 5 days 20 hours ago) and read 9561 times:

Quoting e38 (Reply 5):
I'm not familiar with procedures at other carriers, but at Delta, on the A-320/A-319 fleet, the landing lights are extended as the aircraft descends through 10,000 feet AGL. This is to increase aircraft visibility in the low altitude environment. Therefore, the landing lights are on well before the aircraft is on final approach.

Well, yeah... hence a person standing on the approach path can hear it!!!  
But thanks for your detailed explanation as to why we use landing lights on airplanes. You must be a pilot!


I'm sticking with my answer- it's landing lights.


User currently offlineDocLightning From United States of America, joined Nov 2005, 20362 posts, RR: 59
Reply 19, posted (2 years 4 months 1 week 5 days 19 hours ago) and read 9528 times:

Quoting WingedMigrator (Reply 17):
It starts very suddenly, but it's probably not related to any deployment event because it always starts with the same angle between the plane of the fans and the line of sight of the observer. Try paying attention to that next time, and you'll hear/see what I mean.

No, because I've heard it stop just as suddenly when the aircraft was heading towards me on climb-out. "ShuuuuUUUUUUP!" and then it sounds like a 737.


User currently offlineB6JFKH81 From United States of America, joined Mar 2006, 2902 posts, RR: 7
Reply 20, posted (2 years 4 months 1 week 5 days 19 hours ago) and read 9516 times:

Quoting WingedMigrator (Reply 17):
you are talking about the sudden-onset whine that drops rapidly in pitch and morphs into the regular sound of an airplane flying overhead, right?

Negative, it is a harmonic sound that changes pitch really only due to the dopplar effect as it passes over (higher pitch as it comes towards you, lower pitch as it moves away from you). It's not sudden-onset, and at the altitude they pass over my house while on approach (4000 to 5000 feet) that harmonic sound actually does stay louder than the engine rumble (especially on the V2500-equipped birds). I have been trying to find some footage online but I'm not finding any that really represent the harmonic whine that I am referencing, I may have to take my own vid if I have time/effort. I think I am referencing a different "whine" than the OP.



"If you do not learn from history, you are doomed to repeat it"
User currently offlineWingedMigrator From United States of America, joined Oct 2005, 2260 posts, RR: 56
Reply 21, posted (2 years 4 months 1 week 5 days 12 hours ago) and read 9441 times:

I guess it's hard to use words to describe sounds with any accuracy...

User currently offlineLH707330 From United States of America, joined Jun 2012, 849 posts, RR: 0
Reply 22, posted (2 years 4 months 1 week 5 days 11 hours ago) and read 9426 times:

Quoting DocLightning (Reply 19):
No, because I've heard it stop just as suddenly when the aircraft was heading towards me on climb-out. "ShuuuuUUUUUUP!" and then it sounds like a 737.

I think that might be a wind-related thing, where the sound waves stack up, so you hear a faint sound, then the rapidly descending noise followed by the normal 737/A320 etc. noise.


User currently offline747fan From United States of America, joined Jun 2007, 1192 posts, RR: 1
Reply 23, posted (2 years 4 months 1 week 2 days 14 hours ago) and read 9032 times:

The A320-series "UFO whine" is also evident on climbout. I notice it more when the airplane is several thousand feet up, as its not being drowned out by as much actual engine noise.
The Airbus narrowbodies (especially the one 30 seconds into the footage) on approach in this video perfectly demonstrate the noise:

http://www.youtube.com/watch?v=8g0TWFUDDtE

This sound definitely isn't caused by the flaps being lowered as most aircraft in this video are in clean configuration. I've always been curious about the cause of this sound; seems to be aerodynamically related rather than engine related since the sound is the same regardless of if its CFM or IAE-equipped.

[Edited 2012-08-18 19:19:49]

User currently offlineogshelly From United States of America, joined Feb 2005, 26 posts, RR: 0
Reply 24, posted (2 years 3 months 3 weeks 2 days 14 hours ago) and read 7973 times:

I can distinguish that particular sound of the Airbus, and I believe its RR engines are the root cause. And speaking of noise, I love the 757's fitted with RRoyce engines, another easily ID roar! The old 747's made a music for the ear take off sound, I think it was double the number of 757 engines, anyone?

25 Post contains links and images RyDawg82 : Just tonight while walking my dog I was thinking about the cause of this very noise as a A320 passed overhead. It's an interesting theory on the landi
26 DocLightning : I will note that in the video you reference, the A320 is in a clean configuration (or at least a very low flaps setting) but yet it has the landing l
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