MYSTERIOUS BARKING SOUND on AIRBUS? All about the PTU explained by "Captain"Joe

  • Published on Mar 2, 2017
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    Dear Friends and Followers!
    What is that barking sound coming from below the cabin floor as soon as we reach the gate position? Have you ever wondered what is going on in the cargo compartment where this very strange noise is coming from. Many people refer to this as the "Airbus Barking Dog Sound".
    This strange barking sound emits from the PTU, the Power Transfer Unit which is a substantial part of the Airbus hydraulic system. I explain in further detail when the PTU is being operated and it´s purpose.
    Now the Airbus A320 hydraulics consist of three independent system, named in colours, green, blue and yellow and one of their highest priorities is to pressure the actuators to move the flight controls.
    the green system is powered by an engine driven hydraulic pump, engine number 1, so in flying direction the engine to your left hand side and the yellow system is powered by engine number 2 but can also be powered by an electric backup pump.
    The blue system is powered by an electric pump only but isn´t associated with the PTU. It does, however, have its own unique backup mechanism, the Ram Air Turbine, but that´s a whole another video.
    So imagine the PTU as a reversible motor pump located between the green and yellow systems. Hydraulic fluid from either system can drive the pump to pressurise the other hydraulic system. But the fluids only drive the pump so the remain isolated from each other, meaning they don´t mix
    Each hydraulic system normally operates at 3000psi and if the difference between the green and yellow system exceeds 500psi, the system energises the PTU to pressurise the low system. In other words, the green or yellow hydraulic pump has failed and is being pressurised from the other system through the PTU.
    What the video for more information :)
    Thanks for your time and see you next thursday. Make sure to stop by my Instagram account at "flywithcaptainjoe" and subscribe my channel for more upcoming video.
    All the best, Your "Captain" Joe
    ONE MISTAKE IN VIDEO, you preferably start engine number 2 first and then engine number 1, in that sequence! Sorry about that !
  • Science & TechnologyScience & Technology

Comments • 1 688

  • JP Stone
    JP Stone 3 days ago

    Huh, good to know always thought that was the fuel pump

  • Pü55ÿ Kâť
    Pü55ÿ Kâť 8 days ago

    Yeah if I ever become a pilot on long haul flights ill not be the one to land cause I only understand so little on how to descend

  • Liberty Valdemar
    Liberty Valdemar 12 days ago

    I Also Hear That After 25 Seconds Of Takeoff

    JETSAM AVIATION 15 days ago +1

    The plane clearing its throat.

  • Ellen Johnson
    Ellen Johnson 17 days ago

    I think I love him.

  • Shaderite Matobit
    Shaderite Matobit 18 days ago

    Sounds like a windshield wiper noise to me. I actually asked one of the pilots of the flight I was in. I got the answer right xD

  • WSWEss
    WSWEss 19 days ago

    very unclear... its a dog

  • Stephen Kurian
    Stephen Kurian 21 day ago

    I have never been on an airbus but when I got to ride on an airbus I knew what the sound was because of this video

  • ValenTheBest_ 2018
    ValenTheBest_ 2018 23 days ago +1

    I thought the sound was the wipers being tested!

  • Niall Dowling
    Niall Dowling 23 days ago

    Then why does it follow me home?

  • Fudgee s
    Fudgee s 24 days ago

    i thought, Its the cargo door closing..

  • Simon-_-88
    Simon-_-88 Month ago

    It sounds like someone sawing the plane in half

  • Gabor M
    Gabor M Month ago

    I heard pumping sound while climbing after the take-off. Is this the same sound or a different one?

  • GamePotato 17
    GamePotato 17 Month ago

    I thought it was the flaps

  • ShaunLee Gaming
    ShaunLee Gaming Month ago

    I thought it was the flaps. Are you supposed to adjust the flaps only next to the runway or before the plane taxi’s?

    • A2DJP
      A2DJP 27 days ago +1

      ShaunLee Gaming generally it’s before taxi. But flaps are checked multiple times on checklists before take off.

  • Hi, im Joe
    Hi, im Joe Month ago +1

    If it isn’t Boeing, I’m not going.

  • Yihao Li
    Yihao Li Month ago +1

    Great video! I'm been wondering about this question for YEARS!

  • Pionel tapinessi
    Pionel tapinessi Month ago

    What does it mean when I hear this all flight long including cruising.

  • ItsMeJay
    ItsMeJay Month ago

    I heard this noise when i flew from Washington Dulles to Mexico City on an 737-800. And I heard it when we started taxi taxi was about 25 minutes.and when we parked at the gate.

  • Jake Chen
    Jake Chen Month ago

    Is this barking on the A319?

  • Abhijit Kashyap
    Abhijit Kashyap Month ago

    This is how the A320 responds whenever it sees a Boeing 737 Max 8 on the tarmac.

  • Ela Baršváryová
    Ela Baršváryová Month ago

    I just heard this yesterday on our Airplane from Madrid to Vienna when we landed! To me it sounded more like sawing wood or something, but now that you mentioned a barking dog, it totally DOES sound like that too. Good to know, thank you for this video, I was wondering about it :)

    ABHIJIT DAS 2 months ago

    But captain my last A320 journey this sound was heard after take off also why this sound is lasting after take off

    ABHIJIT DAS 2 months ago

    Thanks captain it was my question now I am happy to know the cause of the strange sound. Thanks a lot

  • midnightoilburner
    midnightoilburner 2 months ago

    Thank you, Joe! That was my number one aviation conundrum. It was hard asking anybody because I couldn’t find words to describe that sound.

  • Hemant Thakur
    Hemant Thakur 2 months ago


  • miss martinez xo
    miss martinez xo 2 months ago

    I was on easyJet and I heard it before we took off and when we landed

  • erik planespotting
    erik planespotting 2 months ago

    Windscreen wiper beacause it sounds like the windscreen wiper from my grandmas 18 years old opel (for the britains here vauxhaull) Agila

  • AdamAir737400
    AdamAir737400 2 months ago +4

    Oh, that's why I hear a sound on the a320 I rode a few months back. Thank you for the information!

  • Albert Tseng
    Albert Tseng 2 months ago

    I have only flown Airbus A319, A320, and A321 a total of 5 times, But I have flown The Boeing 787 much more times, and the sound sound more like the gears

  • CLash
    CLash 3 months ago

    I always thought they were just testing the rudder

  • Jean Viloria
    Jean Viloria 3 months ago

    This happened to me in an airbus A320

  • Gerardo Ramón
    Gerardo Ramón 3 months ago

    And what if i hear a "booting down sound" while the engines are turn off while the plane is arriving at the gate?

  • Amusement Park Studios
    Amusement Park Studios 3 months ago

    I’ve heard that sound during takeoff as well

  • Deisterflieger
    Deisterflieger 3 months ago

    Nice, I ever was afraid to ask.

  • Rob Johnson
    Rob Johnson 3 months ago

    It ain't called ScareBus for nothing.

  • Bryan Holland
    Bryan Holland 3 months ago

    We just took a flight on Frontier from ORD-PUJ and then later back to ORD. It was my girlfriends first time on an Airbus 320, and I jokingly told her she might hear dogs barking. Oddly enough, we only heard it on our return flight, during pushback was not a surprise; but I was a bit frightened when it happened during the landing phase constantly from gear down during decent through retraction of flaps after touchdown. It was an A32N N307FR

  • David Reibelt
    David Reibelt 3 months ago

    THANK YOU JOE. I have wondered what this noise is for years. Only ever heard it when pushing back but never used to hear it in older jets (ive been flying since 1975!) Never thought of it as a barking dog :)

  • Trist Drew
    Trist Drew 3 months ago

    I heard this sound before landing on EasyJet a320 last week. Would it have been to adjust pressure or to start second engine perhaps?

  • 999mario1
    999mario1 3 months ago

    Well what does the boing 737 have then?

  • Greg Lum
    Greg Lum 3 months ago

    First time I was on an A320 and heard that sound I was amused as it sounded like the pilot was trying to turn over the engine with a weak battery. I heard someone in the back say "Pilot needs a jump" which got some laughs

  • Joshua Hall a.k.a. Controlla

    Great video.☺️ I think I’ve watched this video before.☺️

  • Apples
    Apples 3 months ago

    I don't know... What to do with my hands.

  • Jmen TFT
    Jmen TFT 3 months ago

    Hey! Captain Joe, did you ever used autopilot for landing? I mean completely without human involving during landing. As far as I know there are some airports that allows such type of landing. Could you, please, tell more about it? Thanks! :-)

  • Aristopaido Aristo
    Aristopaido Aristo 3 months ago +1

    I heard that on final approach. My mom said that the sound came from the landing gears! Was she right or I was in danger!? Captain plz answer me!

    • John Ham
      John Ham 18 days ago

      You wouldn't hear this specific sound on approach. It may have been the landing gear, sounds like someone dropped something heavy on the floor, or maybe it was a flaps adjustment

  • saraswathi janakiraman
    saraswathi janakiraman 4 months ago +1

    Hey Joe! Please make a video on Airbus parking brakes. You response should not only be in Instagram, should also be in TVclip. Also I have subscribed for channel because you are a captain who is explaining very well. There are so many TVclip channels but I have chosen yours because of this reason. So, please make a video on this topic and it's my great request. And if you made please send me the link as a reply in my comment.

  • qwerty keyboard
    qwerty keyboard 4 months ago

    Been wondering about the sound ever since my first time riding an A320. Finally found the answer after 10 years. Thanks for sharing this, Cap.

  • blackmore1030
    blackmore1030 4 months ago

    That's why luggages often get torn: there are dogs in the baggage area that chew them :D

  • 4dMiNi5Tr4t0r
    4dMiNi5Tr4t0r 4 months ago

    I have always wondered what that sound was! Thought it was the flaps being set, but I was wrong :)

    FUGLY 4 months ago

    Star boat

  • Ishaan Banerjee
    Ishaan Banerjee 4 months ago

    Why can't we turn both engines on at same time?

  • THESlovz1
    THESlovz1 4 months ago

    Best explanation

  • arifhakimihasbaan arifhakimi

    Make a video about what happen to MH379

  • jemmerx
    jemmerx 4 months ago

    I pretty sure I've heard this sound in the air before. I'd surmised at the time that it was the electric conveyors for the baggage containers in the hold shifting the containers to alter the balance of the aircraft.
    Is there a reason the PTU would activate during flight?

  • Richie Kock
    Richie Kock 4 months ago

    Captain Joe: do captains bang the stewardesses? thats the biggest mystery we wish to know?

  • Rosidaham Mohd
    Rosidaham Mohd 4 months ago

    Hahaha.. on my 1st time flight with airbus A320.. i remember asking to one of the passenger.. "what are they renovating out in the back"?

  • turbofanlover
    turbofanlover 4 months ago

    Well, the good news is no more barking for Captain Joe now that he has moved up (way up) in class and gets to fly the Queen (of the Skies). :)

  • Cavaughn Haynes
    Cavaughn Haynes 4 months ago

    I heard that noise once when I was young and I thought I was hearing a dog barking sound for a second and ignored it because no one else heard it with all the bags getting took down

  • Sean Breheny
    Sean Breheny 4 months ago

    I think I've often heard this noise during the entire taxi, while only one engine is running. Would there be a reason why the crew would not turn on the electric back-up pump as you said?

  • David Sochor
    David Sochor 4 months ago

    3:38 good job anticipating this question, exactly what popped up in my head after first part of the video.

  • Fox Charlie Sim
    Fox Charlie Sim 4 months ago

    Startin up an A320 on Xplane11 simulator i heard the dogs barking a 5 minutus ago. Now im here in your page seeing this video! Amazing explanation! lol

  • Mr. Patrick. Chocolate. CHEESECAKE.

    Who here has never been on an Airbus and is wondering what he’s talking about.

  • Gerardo Bono
    Gerardo Bono 4 months ago

    aaaaaaand mistery solved. Great videos Capt!

  • Johnny Eusebio
    Johnny Eusebio 4 months ago

    Wow! I was always wondering what that angry dog barking noise is! THANKS😀

  • stefan tatalovic
    stefan tatalovic 4 months ago

    The most annoying sound ever to hear in a hangar. When i first heard it i thought it was broken

  • Remy B
    Remy B 4 months ago

    For me it doesn't sound like a dog bark

  • Nostalgia 鄕愁
    Nostalgia 鄕愁 4 months ago

    Someone must be cleaning the Airbus's window lol

  • Jasmine Johnston
    Jasmine Johnston 4 months ago

    I flew in an Airbus plane before but I never heard that noise. I think the plane was an A330 or something...

  • mart f
    mart f 4 months ago

    Moishy Ok is a stupid person.

  • mart f
    mart f 4 months ago

    Moishy Ok is a fucktard

  • Иван Lite
    Иван Lite 4 months ago

    Ahh! Ahh! Ahh!

  • Ruby Bell
    Ruby Bell 4 months ago

    No it’s just because the aircraft sees a Boeing

  • Slippery Slime
    Slippery Slime 4 months ago

    I heard it after take off and before landing. I thought it was the landing geek going down since I was next to the wing. But then I realised that the pilots might've cut buck the engines. But there bossily also may be a really loud dog in the cargo bay.

  • Leonardo Angeletti
    Leonardo Angeletti 4 months ago

    If the yellow system powers the steering and brakes, why don't they shut down engine 1 and leave engine 2 running?

  • Aleatha Vogel
    Aleatha Vogel 4 months ago

    1:36 - _Ram Air Turbine_. So you're saying Airbus planes are powered by dogs and RATs. Got it! lol ;) On a side note, the fastest and easiest way I've found to explain a Ram Air Turbine to someone is to tell them it's like a small windmill designed to __*_minimally_* power the plane when no other power source is available (i.e. engines or APU.)

  • Thewarbie jaba
    Thewarbie jaba 4 months ago

    Thanks you cap. Joe

  • Ahmad Sayyed
    Ahmad Sayyed 4 months ago

    Amazing video joe!!! Love ur videos i have learned a lot from ur video

  • Ian H
    Ian H 5 months ago

    I was just wondering about this! I was going to say it sounded like a sawing sound!

  • Oh my gosh Is that bread?

    Maybe the dogs in the cargo hold got restless…

  • Oliver Marriott
    Oliver Marriott 5 months ago

    I've never noticed this sound and I've been on a a321 twice 🤔

  • Emre
    Emre 5 months ago

    This is an interesting topic. Thank you for being in youtube :))

  • Way Lingaw
    Way Lingaw 5 months ago

    Mh first time on airplane when i heared that creepy sounds. And it was like "i think this is it, we are all going to die. Looool

  • Shawn Of The Flynn
    Shawn Of The Flynn 5 months ago

    I heard the barking noise last year on holiday the plane was approaching for landing went on for a good 5 minutes all of us were very confused hahaha

  • Kai Grijff
    Kai Grijff 6 months ago

    Joe, please explain next thing to me: monday I was flying with an A320 which used the single-engine taxi procedure. It took about 12 minutes to taxi to the runway. The barking sound was heared when engine no. 1 was started and on idle speed. After the barking sound was heard a few times, it remained silent and the only thing sounding, was the (I think) electrical driven hydraulic pump of the yellow circuit. This continued untill the engine no. 2 was started, the barking sound was heard again for only a few times. Why wasn't the barking sound heard the whole time during taxi? Does it have someting to do with no acuating parts on the yellow circuit during taxi, except the NWS?

  • MyTech
    MyTech 6 months ago

    It was a chainsaw, one of the bags was too heavy.

  • Cal
    Cal 6 months ago +1

    Ah yes, the sound of the barking dog, telling you that you are underway and your holiday has begun.

  • H.K.
    H.K. 6 months ago +1

    Green system powers nosewheel steering on some older aircraft.
    Changeover to yellow was about mid 2008.
    If an operator taxis out on left engine only, you will hear this noise if the yellow electric pump was not placed on, then PTU will not run.

  • Thermmo Dhynamics
    Thermmo Dhynamics 6 months ago

    So if I understand well, PTU operation at gear-up, repeatedly in mid-flight, gear-down and during both engines taxi is not a good sign ?
    Specifically, at gear-up, wouldn't that be a good reason for a return to the departure airport?
    Last week after landing I asked the captain of that AF regional flight but he just looked strange, visibly uncomfortable, and said that it happens every now and then.
    Thanks in advance for knowledgeable answers, tail wind ;)

  • Carter Ellis
    Carter Ellis 6 months ago

    Please make video on the back up tubine i remember when i would see that on maday.
    Edit: I just found a video that you made on the turbine.

  • You Know
    You Know 6 months ago

    Why Captain Joe, when not a captain?

  • Santiago Burgos De La Cruz

    Hey captain why do we need ground clearance before using the PTU?

  • Sebastian Contreras
    Sebastian Contreras 6 months ago

    I've only flown on a A320 (Avianca, SMR-BOG) once, and I did noticed and wondered what that was, but hadn't thought much of it (or even remebered) until I saw this video lol

  • gingerbread man1980
    gingerbread man1980 6 months ago

    Ptu good for dog noise

  • Maxime Ordureau
    Maxime Ordureau 6 months ago

    After so many years wondering what that sound is i finally no. Thank you so much for uncovering this mystery it was for me. Always thought it was a screw locking mechanism in cargo doors.

  • John A2007
    John A2007 6 months ago

    My mom says that the sound is the crew selling the door

  • Streptokokke 100
    Streptokokke 100 6 months ago

    In summer we had our two dogs in the cargo compartement. Their barking could easily be heard in the cabin (on ground). So it's not always the PTU. Sometimes it's Freddy and Jimmy.

  • Mico Carlo Adrian Ruiz
    Mico Carlo Adrian Ruiz 6 months ago

    Aerosoft, Wilco and AirSimmer be like....

    All: did...... we....... just........ miss......... a.................... such big.......... detail?
    Aerosoft: well glad im the one who is the best in 3D models and graphics
    Wilco and AirSimmer: well we made a great Airbus family for FS2004
    All: but we all fucked up on this
    Aerosoft: suck it, im making GSX
    Wilco: imma stick with AirSimmer
    AirSimmer: im ginna create that bark for you

  • sahoran shergill
    sahoran shergill 6 months ago

    Can you please tell us the difference between crosswinds, tailwinds and turbulence

  • Mark Volpe
    Mark Volpe 7 months ago

    I hear that noise on other planes that i've been on also, like the MD-88's, but it's usually during or after the luggage has been loaded and before pushback.

  • Amit Parmar
    Amit Parmar 7 months ago

    No dogs were hurt during takeoff