Airbus Sounds

[av8or91]

What are those horrible sounds before and after engine start up? Also while braking there is always this clunking sound. Anyone have any idea?

[SeanD]

Originally Posted by av8or91

What are those horrible sounds before and after engine start up? Also while braking there is always this clunking sound. Anyone have any idea?

You mean the drill sounds? If so I think that is the APU.

[Maximillian_Jenius]

Originally Posted by SeanD

You mean the drill sounds? If so I think that is the APU.

...so, then what's the dog barking sound when the engines start. Geez, the A320 is a loud plane.

[ASpilot2be]

Originally Posted by Maximillian_Jenius

...so, then what's the dog barking sound when the engines start. Geez, the A320 is a loud plane.

Really? I rode on an A320 to and from Vegas for NJC, didnt even notice many of these sounds.

The only sound on a 737NG is the overhead bins squeaking on taxi

[Swen]

I was recently on a NWA A319 and believed there to be a monkey down in the cargo bin fixing stuff with a pneumatic drill all flight. Either that or doing wheel changes on the strollers.

[BobDDuck]

It's the hydraulic system.

[Maximillian_Jenius]

Originally Posted by BobDDuck

It's the hydraulic system.

...it sucks!

[Doug Taylor]

Originally Posted by Maximillian_Jenius

...it sucks!

It's actually a pressure pump, dingleberry. Partial

[av8or91]

Originally Posted by Swen

I was recently on a NWA A319 and believed there to be a monkey down in the cargo bin fixing stuff with a pneumatic drill all flight. Either that or doing wheel changes on the strollers.

Most of the airbus' Ive heard these sounds on are Northwest a319's and a320's. Just wondering of there was maybe some airbus pilots on here that could explain why there it sounds like a monkey is down in the cargo baggage area with a jackhammer and pnematic drill changing stroller wheels sound. HAHA nice one swen

[JA Yawd Bwoy]

I actually think the A320/(21 in my case) is very quiet, besides when the engines rev for takeoff, but I like that sound. Come to think of it the A340 and A321 carry the same engine, no?

[Maximillian_Jenius]

Originally Posted by Doug Taylor

It's actually a pressure pump, dingleberry. Partial

Geez, someone is pissy tonight?

Not trying to start a Boeing v Airbus discssion, but just never heard all that noise on a compariable Boeing aircraft.

Doug, no fair you made me cry!

Calling Kristie in 5, 4, 3, 2...

[Doug Taylor]

Yup, I'm a little cranky. I started this trip, I left Jetcareers, I come back online and I have to check the URL window to make sure it's the same site!

[Maximillian_Jenius]

Originally Posted by Doug Taylor

Yup, I'm a little cranky. I started this trip, I left Jetcareers, I come back online and I have to check the URL window to make sure it's the same site!

Oh, fo sho...

But Max's hands have no blood on em.

[Doug Taylor]

There Will Be Blood.

Oh, I just like saying that! HA!

Ok, I'm going back to bed.

[Maximillian_Jenius]

Originally Posted by Doug Taylor

There Will Be Blood.

Oh, I just like saying that! HA!

Ok, I'm going back to bed.

Or, how bout' There will be Pokemon!?

[OldTownPilot]

Yep hydraulics. Very noticeable if you are near the wing area, not so much in other parts.

The same noise can be heard in the back of an ERJ during a single engine taxi.

[av8or91]

Ok, so I found out exactly what those sounds are.
What you hear is a device called the power transfer unit, or PTU, which is designed to ensure adequate hydraulic pressures during single-engine operations. To conserve fuel, it's fairly routine for two-engine planes to taxi with an engine shut down. Each engine normally pressurizes its own hydraulic system, but with a motor not running, that leaves one system without a power source. That's where the PTU comes in, helping left power the right, or right power the left. Since it is activated only when the pressure falls below a certain level, the PTU cycles on and off, on and off. It also does a self-test when the right engine is started, so you'd hear it then as well, regardless of hydraulic pressures.

That's the short answer, which ought to appease the typical nervous or curious rider. For gearheads, or those wishing to impress (or bore) their seatmates, here's a description by correspondent Dave English, Airbus A320 pilot and aviation writer:

"The A320 has two main hydraulic systems that operate flaps, landing gear, flight controls, cargo doors and brakes. These are called Green and Yellow. This has nothing to do with the color of the hydraulic fluids; they're just useful labels. The Green system is powered by the number 1 (left) engine-driven pump. The Yellow system is powered by the number 2 (right) engine-driven pump. Should we lose or depower an engine-driven pump, there is a neat device called PTU -- a two-way reversible motor pump that allows the Green system to pressurize Yellow, or Yellow to pressurize Green. When you taxi with only one engine running, the PTU kicks in to power the opposite side. There is no fluid transfer, keeping each system otherwise independent."

English points out that the PTU racket is not audible from the cockpit. "But," he admits, "it's annoying as heck in the main cabin." It's anybody's guess why Airbus didn't come up with quieter machinery, and most non-Airbus aircraft employ a different layout altogether.

In the United States, the largest operators of A320s and/or A330s are JetBlue, Northwest, U.S. Airways and United. To reduce PTU noise, some airlines ask crews to run a separate electric pump during single-engine taxi.

[USMC-SGT]

You found out because you asked at APC and then I found out and informed you who then posted here.

Technically whoever wrote that article found out and then I refound out and then you re-refound out.

[Swen]

I still think its a monkey changing stroller wheels in the cargo bin.

[Maximillian_Jenius]

...so, while were still talking about Airbus sounds. Can anyone give me a solid answer on what causes the "whistling" or "blow dryer" sound when Airbus aircraft (more especially the A320) are low and on approach.

Is it a power setting on the engines, or the boards up, or something else?

[Polar742]

I thought those noises were the French plane lowering the White Flag after every flight.

[av8or91]

Originally Posted by USMC-SGT

You found out because you asked at APC and then I found out and informed you who then posted here.

Technically whoever wrote that article found out and then I refound out and then you re-refound out.

Well sorry, I should have said thanks to USMC-SGT on APC. So this is all thanks to USMC-Sgt he found out for me thanks.

[UPSpilot]

Originally Posted by Polar742

I thought those noises were the French plane lowering the White Flag after every flight.

Airbus planes don't have an engine failure checklist. They have an engine capitulation checklist.

[Polar742]

I know, I know, that just ain't right.....

[ILSstud]

.....a visual aid :-)http://youtube.com/watch?v=grd5eJjJcL4