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A330 noise while taxiing

  • 23-04-2019 8:46pm
    #1
    jc11
    Registered Users, Registered Users 2 Posts: 175 ✭✭


    Hi there,

    Was recently on AL a330 and during the taxi there was a strange sound, nearly like the grinding sound of a train going over tracks coming into a station if that makes sense?!

    It was not the barking type Noise associated with airbus (have heard this noise before and was totally different!)

    Anyone able to shed some light on what it could be?

    TIA


Comments

  • #2
    TheBoyConor
    Closed Accounts Posts: 3,292 ✭✭✭TheBoyConor


    Hydraulics can be noisy in some planes.


  • #3
    faoiarvok
    Registered Users, Registered Users 2 Posts: 645 ✭✭✭faoiarvok


    Power Transfer Unit (the “barking dog”) I believe. Open to correction but I think it moves pressure between the hydraulic systems.


  • #4
    goingnowhere
    Registered Users, Registered Users 2 Posts: 4,286 ✭✭✭goingnowhere


    The parking brake on the A330 makes a very audible clunk


  • #5
    faoiarvok
    Registered Users, Registered Users 2 Posts: 645 ✭✭✭faoiarvok


    faoiarvok wrote: »
    Power Transfer Unit (the “barking dog”) I believe. Open to correction but I think it moves pressure between the hydraulic systems.

    Oh I read the title as A320, may not be the case on the 330


  • #6
    NH2013
    Registered Users, Registered Users 2 Posts: 404 ✭✭NH2013


    faoiarvok wrote: »
    Power Transfer Unit (the “barking dog”) I believe. Open to correction but I think it moves pressure between the hydraulic systems.

    There's no PTU on the A330 like the A320, probably the brakes being used against the wheels.


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  • #7
    Kev11491
    Registered Users, Registered Users 2 Posts: 171 ✭✭Kev11491


    Heard that on one of EI's A332 too, was sitting over the wing and assumed it was just the hydraulics on the landing gear.


  • #8
    Skuxx
    Registered Users, Registered Users 2 Posts: 2,379 ✭✭✭Skuxx


    faoiarvok wrote: »
    Power Transfer Unit (the “barking dog”) I believe. Open to correction but I think it moves pressure between the hydraulic systems.

    On A320 there should be no reason (under normal circumstances at least) for the PTU to operate while the aircraft is taxiing or breaking as both engine pumps would be suppling hydraulic power (3000psi) to their respective system! Most likely to be heard during engine start/ shut down!


  • #9
    jc11
    Registered Users, Registered Users 2 Posts: 175 ✭✭jc11


    Kev11491 wrote: »
    Heard that on one of EI's A332 too, was sitting over the wing and assumed it was just the hydraulics on the landing gear.

    I was sitting near the wing also, im a bit of a nervous flier so some noises can freak me out! Good to know for the next time its something as simple as that!


  • #10
    artanevilla
    Moderators, Education Moderators, Sports Moderators Posts: 10,969 Mod ✭✭✭✭artanevilla


    It's when the plane stops making noises you should worry.


  • #11
    jc11
    Registered Users, Registered Users 2 Posts: 175 ✭✭jc11


    goingnowhere wrote: »
    The parking brake on the A330 makes a very audible clunk

    Have noticed that too, the noise im asking about was a short grinding noise, like metal on metal 😊


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  • #12
    jc11
    Registered Users, Registered Users 2 Posts: 175 ✭✭jc11


    artanevilla wrote: »
    It's when the plane stops making noises you should worry.

    Thats true!! Thanks, you made me giggle there..

    Thanks all for the answers!


  • #13
    lintdrummer
    Registered Users, Registered Users 2 Posts: 1,808 ✭✭✭lintdrummer


    Skuxx wrote: »
    On A320 there should be no reason (under normal circumstances at least) for the PTU to operate while the aircraft is taxiing or breaking as both engine pumps would be suppling hydraulic power (3000psi) to their respective system! Most likely to be heard during engine start/ shut down!

    There is a provision in SOPs to taxi on one engine to save fuel. You may briefly hear the PTU operate on taxi in after the right hand engine is shut down. The yellow electric hydraulic pump is then switched on which will stop the PTU from running. Electric pumps have a loud high pitched whine which is very audible in the cabin.

    It's very possible the OP heard an electric pump running.


  • #14
    Bussywussy
    Registered Users, Registered Users 2 Posts: 956 ✭✭✭Bussywussy


    lintdrummer wrote: »
    It's very possible the OP heard an electric pump running.

    Doubtful on A330 though,pumps a lot quieter, there is a very noticeable hiss and clunking sound during taxiing when application of brakes applied on the A330 especially if your sitting over the wheel well area


  • #15
    tricky D
    Closed Accounts Posts: 9,700 ✭✭✭tricky D


    artanevilla wrote: »
    It's when the plane stops making noises you should worry.
    Or when the cabin crew start worrying.


  • #16
    Rawr
    Registered Users, Registered Users 2 Posts: 4,252 ✭✭✭Rawr


    tricky D wrote: »
    Or when the cabin crew start worrying.

    Or when all of the flight crew leave the cockpit and come out to join you in a drinking session....then I'd be a bit worried :P


  • #17
    kona
    Registered Users, Registered Users 2 Posts: 7,525 ✭✭✭kona


    Its the brake shuttle valve.


  • #18
    Car99
    Registered Users, Registered Users 2 Posts: 2,531 ✭✭✭Car99


    Skuxx wrote: »
    faoiarvok wrote: »
    Power Transfer Unit (the “barking dog”) I believe. Open to correction but I think it moves pressure between the hydraulic systems.

    On A320 there should be no reason (under normal circumstances at least) for the PTU to operate while the aircraft is taxiing or breaking as both engine pumps would be suppling hydraulic power (3000psi) to their respective system! Most likely to be heard during engine start/ shut down!

    PTU is inhibited during engine start on a 320


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