Airbus- what is that strange noise
Tom P
about the time the engines are being started up. It's not easy to
describe, it's a like someone running a wet finger over a pane of glass,
it's quite loud, and it just lasts a few seconds.
It's not the flap motors or anything else I can identify.
Anyone explain it?
This BTW is on the A319 and A320 which I fly frequently, may be on other
types as well.
T.
--
I dreamed of 747's
over geometric farms
Jim Davis
"Tom P" <notreal...@freenet.de> wrote in message
news:6424dgF...@mid.individual.net...
Most likely in the starting mechanism, of that brand of engine. Each brand
has different sounds. Some engines had a distinct "ratcheting" sound under
high throttle. (I believe it the Rolls-Royce)
A good example is to listen when someone starts their Ford. Then listen to
a Chrysler start. The Chrysler starter has a distinctive high pitched
sound.
James Robinson
> I often hear this strange squeaking noise on Airbusses during pushback
> about the time the engines are being started up. It's not easy to
> describe, it's a like someone running a wet finger over a pane of glass,
> it's quite loud, and it just lasts a few seconds.
> It's not the flap motors or anything else I can identify.
>
> Anyone explain it?
There are two redundant hydraulic systems on those planes, one pressurized
by a hydraulic pump on the left engine, and the other by a pump on the
right engine. When only one engine is running, there is a hydraulic
motor/pump that uses the pressure in one system to provide pressure in the
system without the running engine. People describe it as sounding like a
barking dog, sawing wood, or a car engine trying to start, but barely
turning over.