# Barking sound on airplanes **URL:** \ **Category:** Factual Questions\ **Created:** [September 30, 2014, 8:49am UTC](https://boards.straightdope.com/t/barking-sound-on-airplanes/699949 "2014-09-30T08:49:31Z")\ **Posts on this page:** 19\ **Page:** 1
**Author:** ![beowulff](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/beowulff/32/542_2.png) [@beowulff](https://boards.straightdope.com/u/beowulff)\ **Post date:** [September 30, 2014, 8:49am UTC](https://boards.straightdope.com/t/barking-sound-on-airplanes/699949/1 "2014-09-30T08:49:31Z")
I often hear a “barking” or “woofing” sound on airplanes after I land. I’ve always assumed that it’s the sound that some ballscrews make, but I don’t know what they are adjusting. I’ve never been able to see any flaps or wing extensions moving. Anyone know what makes this sound (it seems to come from under the floor)? ---
**Author:** ![bob\_2](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bob_2/32/3341_2.png) [@bob\_2](https://boards.straightdope.com/u/bob_2)\ **Post date:** [September 30, 2014, 9:11am UTC](https://boards.straightdope.com/t/barking-sound-on-airplanes/699949/2 "2014-09-30T09:11:53Z")
It’s entirely possible that there are dogs in the hold: - > [@](#): > > Whether your pet is flying as checked baggage or cargo, it will travel in a temperature controlled and pressurized compartment right under the cabin. Most airlines flying larger aircraft (not commuter planes) accept live animals as cargo and have made special provisions for their handling. \*[http://www.pettravel.com/passports\_container\_requirements.cfm](http://www.pettravel.com/passports_container_requirements.cfm) ---
**Author:** ![PaulParkhead](https://avatars.discourse-cdn.com/v4/letter/p/7ea924/32.png) [@PaulParkhead](https://boards.straightdope.com/u/PaulParkhead)\ **Post date:** [September 30, 2014, 9:31am UTC](https://boards.straightdope.com/t/barking-sound-on-airplanes/699949/3 "2014-09-30T09:31:21Z")
It is probably the [Power Transfer Unit](http://www.askthepilot.com/questionanswers/the-barking-dog-airbus-noises/) that you’re hearing. Basically, it maintains hydraulic pressure especially when only one engine is running. As far as I can tell, it’s just the twin-engined Airbus models that make the noise. ---
**Author:** ![beowulff](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/beowulff/32/542_2.png) [@beowulff](https://boards.straightdope.com/u/beowulff)\ **Post date:** [September 30, 2014, 10:17am UTC](https://boards.straightdope.com/t/barking-sound-on-airplanes/699949/4 "2014-09-30T10:17:50Z")
> [@PaulParkhead](#): > > It is probably the [Power Transfer Unit](http://www.askthepilot.com/questionanswers/the-barking-dog-airbus-noises/) that you’re hearing. Basically, it maintains hydraulic pressure especially when only one engine is running. > > As far as I can tell, it’s just the twin-engined Airbus models that make the noise. Yes, that’s it, thank you. I just got off an A320, and was reminded about asking the question, after hearing it. ---
**Author:** ![Richard\_Pearse](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/richard_pearse/32/13144_2.png) [@Richard\_Pearse](https://boards.straightdope.com/u/Richard_Pearse)\ **Post date:** [September 30, 2014, 10:54am UTC](https://boards.straightdope.com/t/barking-sound-on-airplanes/699949/5 "2014-09-30T10:54:12Z")
> [@PaulParkhead](#): > > It is probably the [Power Transfer Unit](http://www.askthepilot.com/questionanswers/the-barking-dog-airbus-noises/) that you’re hearing. Basically, it maintains hydraulic pressure especially when only one engine is running. > > As far as I can tell, it’s just the twin-engined Airbus models that make the noise. Yes. There are actually many aircraft that are capable of making that, or a similar, noise, but it seems to be the Airbusses whose design means it is regularly heard by passengers. ---
**Author:** ![Novelty\_Bobble](https://avatars.discourse-cdn.com/v4/letter/n/a3d4f5/32.png) [@Novelty\_Bobble](https://boards.straightdope.com/u/Novelty_Bobble)\ **Post date:** [September 30, 2014, 11:57am UTC](https://boards.straightdope.com/t/barking-sound-on-airplanes/699949/6 "2014-09-30T11:57:47Z")
> [@Richard\_Pearse](#): > > Yes. There are actually many aircraft that are capable of making that, or a similar, noise, but it seems to be the Airbusses whose design means it is regularly heard by passengers. +1 This year, we heard precisely this sound on an Airbus A320 flying to Lisbon and I’d never heard it before. As always, I glanced at the crew and they were very matter-of-fact so I ignored it. It was very loud and I wonder if it is far more noticeable where we seated? (just aft of the wing) And I think the plural of airbus is airbussi 🙂 ---
**Author:** ![Bear\_Nenno](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bear_nenno/32/3358_2.png) [@Bear\_Nenno](https://boards.straightdope.com/u/Bear_Nenno)\ **Post date:** [September 30, 2014, 12:32pm UTC](https://boards.straightdope.com/t/barking-sound-on-airplanes/699949/7 "2014-09-30T12:32:49Z")
Example of what the OP is hearing: [![](https://img.youtube.com/vi/_ZLcVT3OafQ/hqdefault.jpg "Airbus A321 PTU") ](https://www.youtube.com/watch?v=_ZLcVT3OafQ) ---
**Author:** ![KCB615](https://avatars.discourse-cdn.com/v4/letter/k/ea666f/32.png) [@KCB615](https://boards.straightdope.com/u/KCB615)\ **Post date:** [September 30, 2014, 4:52pm UTC](https://boards.straightdope.com/t/barking-sound-on-airplanes/699949/8 "2014-09-30T16:52:38Z")
Absolutely the PTU. The joke with Airbuses is that the noise is the dog that helps fly the plane. An Airbus needs three things to fly: a computer, a pilot, and the dog. The computer flies the aircraft, and the dog bites the pilot if he touches the computer. ---
**Author:** ![Sigene](https://avatars.discourse-cdn.com/v4/letter/s/df788c/32.png) [@Sigene](https://boards.straightdope.com/u/Sigene)\ **Post date:** [September 30, 2014, 7:26pm UTC](https://boards.straightdope.com/t/barking-sound-on-airplanes/699949/9 "2014-09-30T19:26:18Z")
I had a question a few years ago on this exact issue The good old "scare"bus 320 > **[more plane stuff A-319, 320 noise on stopping](https://boards.straightdope.com/sdmb/showthread.php?t=428434)** > > What is with that noise on these planes. When the plane has come to a complete stop at the jetway, there’s some kind of rhythmical sound as they shut something off. For the life of me it always sounds like someone on the ground is taking a very big... ---
**Author:** ![yoyodyne](https://avatars.discourse-cdn.com/v4/letter/y/a9a28c/32.png) [@yoyodyne](https://boards.straightdope.com/u/yoyodyne)\ **Post date:** [September 30, 2014, 7:47pm UTC](https://boards.straightdope.com/t/barking-sound-on-airplanes/699949/10 "2014-09-30T19:47:39Z")
[What it looks like](https://www.youtube.com/watch?v=9ffJgk1-tCA) ---
**Author:** ![PaulParkhead](https://avatars.discourse-cdn.com/v4/letter/p/7ea924/32.png) [@PaulParkhead](https://boards.straightdope.com/u/PaulParkhead)\ **Post date:** [October 1, 2014, 2:12am UTC](https://boards.straightdope.com/t/barking-sound-on-airplanes/699949/11 "2014-10-01T02:12:20Z")
> [@Sigene](#): > > I had a question a few years ago on this exact issue > > The good old "scare"bus 320 > > [more plane stuff A-319, 320 noise on stopping - Factual Questions - Straight Dope Message Board](http://boards.straightdope.com/sdmb/showthread.php?t=428434) I keep hearing this, I dunno, epithet? Why on Earth would you be scared on an A320? ---
**Author:** ![GusNSpot](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/gusnspot/32/436_2.png) [@GusNSpot](https://boards.straightdope.com/u/GusNSpot)\ **Post date:** [October 1, 2014, 6:32am UTC](https://boards.straightdope.com/t/barking-sound-on-airplanes/699949/12 "2014-10-01T06:32:03Z")
A curiosity on Scare Bus. Friend works for AA and when they open one up on “C” checks and stuff you can tell who built which parts of the airplane. Rivets change style & brand, castings are different, the German parts are built way better than other parts, etc… He points out that usually when an metal plane starts to go bad you have rivets that are lose, flanges and braces start bending, all kinds of things even the worst mechanic can see and ask about. The composite ones do not do that, they just fail catastrophically. XRAY you say… Most of the critical parts are buried deep and some have to be removed to be inspected. $$$$$$$$$$$$ and time not producing revenue. There a few things that if they have not been corrected, IMO, make it very hard for pilots to respond safely to a few different situations. The big iron drivers will be along to tell me I am full of it. That it is a safe airplane. Define safe. ( for how long ) Look to Lockheed for design. Loot to Douglas for engineering. And look to Boeing for dam fine airplanes. If it ain’t Boeing, I ain’t going. This is a bit dated but so am I. 😃 Time will tell. I am just waiting. Hope it happens on the ground so no one will die. And maybe they will catch every dangerous thing before it hurts anyone. ---
**Author:** ![slaphead](https://avatars.discourse-cdn.com/v4/letter/s/e9bcb4/32.png) [@slaphead](https://boards.straightdope.com/u/slaphead)\ **Post date:** [October 1, 2014, 9:09am UTC](https://boards.straightdope.com/t/barking-sound-on-airplanes/699949/13 "2014-10-01T09:09:16Z")
> [@GusNSpot](#): > > I am just waiting. Hope it happens on the ground so no one will die. The first A320 was delivered over a quarter of a century ago. How long are you going to wait? ---
**Author:** ![Richard\_Pearse](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/richard_pearse/32/13144_2.png) [@Richard\_Pearse](https://boards.straightdope.com/u/Richard_Pearse)\ **Post date:** [October 1, 2014, 9:47am UTC](https://boards.straightdope.com/t/barking-sound-on-airplanes/699949/14 "2014-10-01T09:47:55Z")
> [@GusNSpot](#): > > The composite ones do not do that, they just fail catastrophically. > XRAY you say… Most of the critical parts are buried deep and some have to be removed to be inspected. $$$$$$$$$$$$ and time not producing revenue. > > And look to Boeing for dam fine airplanes. > If it ain’t Boeing, I ain’t going. And yet it’s Boeing that has produced the worlds first predominantly composite aircraft, the B787. ---
**Author:** ![GusNSpot](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/gusnspot/32/436_2.png) [@GusNSpot](https://boards.straightdope.com/u/GusNSpot)\ **Post date:** [October 1, 2014, 8:17pm UTC](https://boards.straightdope.com/t/barking-sound-on-airplanes/699949/15 "2014-10-01T20:17:16Z")
See, I knew the big iron drivers would make fun of me. Question for A B drivers. When flying small airplanes, if you ever do, do your feet stay on the floor during an unexpected control emergency’s and the plane is going into an unusual & dangerous attitude?? What does the book say? “First wait for the autopilot to fix it?” \* cheap shot \* Do the new A B’s have a lock out for the rudder now. No more vertical stabilizers going to break? Well, judging by my age which you Shirley know, and that the 787 was not around when Douglas was, that I would not like the 787 either. 😃 _“Lets be careful out there.”_ ---
**Author:** ![Elendil\_s\_Heir](https://avatars.discourse-cdn.com/v4/letter/e/7cd45c/32.png) [@Elendil\_s\_Heir](https://boards.straightdope.com/u/Elendil_s_Heir)\ **Post date:** [October 1, 2014, 8:31pm UTC](https://boards.straightdope.com/t/barking-sound-on-airplanes/699949/16 "2014-10-01T20:31:38Z")
> [@KCB615](#): > > Absolutely the PTU. > > The joke with Airbuses is that the noise is the dog that helps fly the plane. An Airbus needs three things to fly: a computer, a pilot, and the dog. The computer flies the aircraft, and the dog bites the pilot if he touches the computer. Heh. Reminds me of this: [Shop Gifts on Funny.com, Share Laughs at Any Time | Funny.com](http://www.funny.com/cgi-bin/WebObjects/Funny.woa/wa/funny?fn=CEW6R&Funny_Jokes=Airplane_Problems) ---
**Author:** ![JKellyMap](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/jkellymap/32/15880_2.png) [@JKellyMap](https://boards.straightdope.com/u/JKellyMap)\ **Post date:** [October 1, 2014, 9:01pm UTC](https://boards.straightdope.com/t/barking-sound-on-airplanes/699949/17 "2014-10-01T21:01:18Z")
> [@KCB615](#): > > Absolutely the PTU. > > The joke with Airbuses is that the noise is the dog that helps fly the plane. An Airbus needs three things to fly: a computer, a pilot, and the dog. The computer flies the aircraft, and the dog bites the pilot if he touches the computer. And the pilot feeds the dog. (Or else he needn’t be there at all!) ---
**Author:** ![Duckster](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/duckster/32/1244_2.png) [@Duckster](https://boards.straightdope.com/u/Duckster)\ **Post date:** [October 1, 2014, 9:03pm UTC](https://boards.straightdope.com/t/barking-sound-on-airplanes/699949/18 "2014-10-01T21:03:15Z")
> [@KCB615](#): > > Absolutely the PTU. > > The joke with Airbuses is that the noise is the dog that helps fly the plane. An Airbus needs three things to fly: a computer, a pilot, and the dog. The computer flies the aircraft, and the dog bites the pilot if he touches the computer. The dog is always busy, too. It’s constantly running, … on a treadmill. ---
**Author:** ![Elendil\_s\_Heir](https://avatars.discourse-cdn.com/v4/letter/e/7cd45c/32.png) [@Elendil\_s\_Heir](https://boards.straightdope.com/u/Elendil_s_Heir)\ **Post date:** [October 2, 2014, 4:21am UTC](https://boards.straightdope.com/t/barking-sound-on-airplanes/699949/19 "2014-10-02T04:21:06Z")
I hear it can be soothed by playing Duran Duran’s “Rio.”