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 • 1 627

  • CLash
    CLash 4 hours ago

    I always thought they were just testing the rudder

  • Jean Viloria
    Jean Viloria 9 hours ago

    This happened to me in an airbus A320

  • Gerardo Ramón
    Gerardo Ramón Day 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

    I’ve heard that sound during takeoff as well

  • Deisterflieger
    Deisterflieger 3 days ago

    Nice, I ever was afraid to ask.

  • Rob Johnson
    Rob Johnson 3 days ago

    It ain't called ScareBus for nothing.

  • Bryan Holland
    Bryan Holland 5 days 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 6 days 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 8 days 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 13 days ago

    Well what does the boing 737 have then?

  • Greg Lum
    Greg Lum 16 days 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 22 days ago

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

  • Jmen TFT
    Jmen TFT 22 days 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 26 days 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!

  • Dugunthi
    Dugunthi 28 days ago

    Sounds more like a low-frequency windscreen wiper than a dog to me.

  • saraswathi janakiraman

    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 Month 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 Month ago

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

  • 4dMiNi5Tr4t0r
    4dMiNi5Tr4t0r Month ago

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

    FUGLY Month ago

    Star boat

  • Ishaan Banerjee
    Ishaan Banerjee Month ago

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

  • THESlovz1
    THESlovz1 Month ago

    Best explanation

  • arifhakimihasbaan arifhakimi

    Make a video about what happen to MH379

  • jemmerx
    jemmerx Month 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 Month ago

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

  • Rosidaham Mohd
    Rosidaham Mohd Month 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 Month 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 Month 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 Month 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 Month 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 Month 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 Month ago

    aaaaaaand mistery solved. Great videos Capt!

  • Johnny Eusebio
    Johnny Eusebio Month ago

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

  • stefan tatalovic
    stefan tatalovic Month 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 Month ago

    For me it doesn't sound like a dog bark

  • Nostalgia 鄕愁
    Nostalgia 鄕愁 Month ago

    Someone must be cleaning the Airbus's window lol

  • Jasmine Johnston
    Jasmine Johnston Month 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 Month ago

    Moishy Ok is a stupid person.

  • mart f
    mart f Month ago

    Moishy Ok is a fucktard

  • Иван Lite
    Иван Lite Month ago

    Ahh! Ahh! Ahh!

  • Flying Polo
    Flying Polo Month ago

    No it’s just because the aircraft sees a Boeing

  • Slippery Slime
    Slippery Slime Month 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 Month 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 Month 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 Month ago

    Thanks you cap. Joe

  • Ahmad Sayyed
    Ahmad Sayyed Month ago

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

  • Ian H
    Ian H Month ago

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

  • Wow I’m a Meme
    Wow I’m a Meme 2 months ago

    Maybe the dogs in the cargo hold got restless…

  • Oliver Marriott
    Oliver Marriott 2 months ago

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

  • Emre
    Emre 2 months ago

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

  • Michael Bonn
    Michael Bonn 2 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 2 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 2 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 2 months ago

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

  • Cal
    Cal 3 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. 3 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 3 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 3 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.

  • Allan Carstens
    Allan Carstens 3 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 3 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 3 months ago

    Ptu good for dog noise

  • Maxime Ordureau
    Maxime Ordureau 3 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 Alberto
    John Alberto 3 months ago

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

  • Streptokokke 100
    Streptokokke 100 3 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 3 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 3 months ago

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

  • Mark Volpe
    Mark Volpe 4 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.

  • Adelaide Aviation
    Adelaide Aviation 4 months ago

    Go to the Airbus Factory see the angry caged dogs powering the machines first hand :D

  • Amit Parmar
    Amit Parmar 4 months ago

    No dogs were hurt during takeoff

  • Haziel Soberal
    Haziel Soberal 4 months ago +1


  • п
    п 4 months ago +9

    Sounds more like a window-cleaning noise to me

  • Mas Rifqi
    Mas Rifqi 4 months ago

    I adore his laugh

  • Paulie Walnuts
    Paulie Walnuts 4 months ago

    Serious question - I’d love to know more about your accent when speaking English. The German intonation sounds so soft and not like any other German I’ve heard speaking English!

  • Airplaneair Gameplays
    Airplaneair Gameplays 4 months ago

    that sound keeps annoying me whenever I'm on that a320 because it scares me

  • Mico Carlo Adrian Ruiz
    Mico Carlo Adrian Ruiz 4 months ago

    Cebu Pacific A320 is on the gate
    Passengers: wha??
    A320: *does it again*
    Passenger: is there a freaking dog here?

  • Jesus Gutierrez
    Jesus Gutierrez 5 months ago

    Captain Joe what is that sound when the landing gear goes up/down? Is it the PTU?

  • Charles Magrin
    Charles Magrin 5 months ago

    "during engine start, engine 2 is not yet running" aren't you supposed yo start engine 2 first on an Airbus?

    RICHARD MARTINEZ 5 months ago

    I heard this sound for the first time on a JetBlue flight from LBG to ATX for the entire flight. It that normal??

  • Panzerkampfwagen VI Ausf Tiger I E

    I heard it on my flight

  • imaad shaikh
    imaad shaikh 5 months ago


  • Tatyana I
    Tatyana I 5 months ago

    that sucked

  • Traci_Angels
    Traci_Angels 5 months ago

    Yep definitely a dog 🐶 😈

  • Komrade BigTex sucks
    Komrade BigTex sucks 5 months ago

    Yeah... I've actually never been on am airbus, only Boeing and Bombardier planes. This is depute me having flown more than 50 times in just the last 10 years.

  • Lee Zinke
    Lee Zinke 5 months ago

    Is there a dog on the plane? lol

  • Ray Espinoza
    Ray Espinoza 5 months ago

    Ok thats a good one cap joe always have a safe fligth God bless airlines

  • Matthew Lo
    Matthew Lo 5 months ago

    I thought this was something related with the Dog of Wisdom video...

  • Franchisemae Castillo
    Franchisemae Castillo 5 months ago

    I actually thought that the cabin doors are closing,,hmm

  • NebNalon
    NebNalon 5 months ago

    We had this on a flight last week. They were doing pre flight startup etc and the noise went on longer than expected. They did this numerous times then declared a fault and called an engineer. 2.5 hours later we took on more fuel and clear to takeoff. Halfway into climbing the barking started, I panicked as I thought this only happened on the ground? Ironically on approach on the return leg using a different plane, the barking started when coming into land - is this usual? I've never heard this in the air before?! New BA procedures?

  • Daniel Haslam
    Daniel Haslam 5 months ago

    Terrain Terrain. Woof Woof! Pull Up! Woof Woof! Pull Up! Woof Woof! Pull up!

  • Ethan H
    Ethan H 5 months ago

    Ooh! I got a Embraer E2 ad!

  • Senor eggnogs
    Senor eggnogs 5 months ago

    he err....he did the german three

  • Sky
    Sky 5 months ago

    Ive been in a a320 a321 a319 A319

  • Taylor Duskwalker
    Taylor Duskwalker 5 months ago

    My little paranoid ass used to think some asshole terrorist tried to cut a wing off using a wood saw. Thank you for the clarification.

  • RFI-Crypto Lab
    RFI-Crypto Lab 5 months ago

    My mom who hasn't flown in decades thought it was a dog.
    Everytime we are taxiing on an A320 I like to listen to people's comments when that pump kicks on.
    Some are curious and a few are always slightly alarmed. If you aren't familiar it does sound like some motor is trying to start but cant.

  • Znek
    Znek 5 months ago

    I heard this on a a319 from Brussels airlines

  • Gamer-exe
    Gamer-exe 5 months ago

    For me it sounds like someone is rubbing a towel on a squeaky clean window

  • sosichan
    sosichan 5 months ago

    I always wondered about the barking!!! Thanks for clearing this up for me 😁