Just by curiosity: what is the loud mechanic noise on Airbus jetsafter landing?

It sounds a bit like a somewhat underpowered concrete drill, 4-5 five
times close to the center of the aircraft.

Who might explain me what just happens?

Thanks

Laszlo

Lazlo Lebrun <lazlo_lebrun@laszlomail.com> wrote:

> It sounds a bit like a somewhat underpowered concrete drill, 4-5 five
> times close to the center of the aircraft.
>
> Who might explain me what just happens?

There are two hydraulic systems, each powered by one engine. When only one
engine is running, there would only be hydraulic pressure in one system,
except the aircraft is equipped with a hydraulic transfer pump, which runs
using hydraulic pressure from the system that is working, and supplies
pressure to the system with the stopped engine. You are probably hearing
that pump running.

"James Robinson" <wascana@212.com> wrote in message
news:Xns9A71A5667FD52wascana212com@66.250.146.128. ..
> Lazlo Lebrun <lazlo_lebrun@laszlomail.com> wrote:
>
>> It sounds a bit like a somewhat underpowered concrete drill, 4-5 five
>> times close to the center of the aircraft.
>>
>> Who might explain me what just happens?
>
> There are two hydraulic systems, each powered by one engine. When only
> one
> engine is running, there would only be hydraulic pressure in one system,
> except the aircraft is equipped with a hydraulic transfer pump, which runs
> using hydraulic pressure from the system that is working, and supplies
> pressure to the system with the stopped engine. You are probably hearing
> that pump running.

Or it could be speed bumps.