Airbus question

[sidestick_rules]

I have flown on Airbus A320-300 in the US with Frontier, USAir, and Northwest. I have a mechanical question:

After the first engine is started and returns to idle, but before the second engine is started, a series of 5-6 grinding/wrenching/twisting noises come from the floor of the fuselage between the wings.

Does anyone know what is causing these noises? Thanks!

[Andries]

I have flown on Airbus A320-300 in the US with Frontier, USAir, and Northwest.

An Airbus A320-300 does not excist. You probably mean an Airbus A320-200.

Greetz,

CanonFreak

[Jense]

Altought I don't know an answer on your question, I have 2 remarks:
- When I look @ Airliners, I don't find an A320-300? (I don't think it excist) And; I don't think Frontier have A320's, only A319's...
- Welcome to Luchtzak... Enjoy this wonderfull aviation-site...

greettzzz

[sidestick_rules]

Wow, this is quite a hostile site. I have an innocent question about a noise, and already two replies that have nothing to do with my question, but instead serve to ridicule me, have been posted. The second reply is even more baffling to me, as the same comment was just made. Perhaps you can find somone else to impress with your particular knowledge; I just want an answer to my question.

[sidestick_rules]

I can see the lack of maturity of the users on this site will contribute nothing for me. I withdraw my membership.

Simultaneously, my question was answered by a retired Northwest pilot just moments ago. I hereby rescind it as well.

[Jense]

- Welcome to Luchtzak... Enjoy this wonderfull aviation-site...

That's what I wrote
We just want to say you that an A320-300 not excist...
I know that the answers were a little bit off-topic, but a reaction like that...
Keep in mind: you are welcome, huh

Altought I don't know an answer on your question...

I tought I was clear

greettzzz

[A318]

Frontier flies A319's and A318's though

Greetz,

Erwin

[Andries]

Wow, this is quite a hostile site. I have an innocent question about a noise, and already two replies that have nothing to do with my question, but instead serve to ridicule me, have been posted. The second reply is even more baffling to me, as the same comment was just made. Perhaps you can find somone else to impress with your particular knowledge; I just want an answer to my question.

This shurely wasn't a hostile reaction, just a correction to the question.
I don't know what you call ridicule of baffling, but this certainly wasn't anything like it !

This site exists to help eachother, not to create hostile situations ... You are more than welcome on this website, like Jense allready said.
Is it so hard to accept that some people try to help you by correcting your question ???

Greetz,

CanonFreak

[SN30952]

I have flown on Airbus A320-300 in the US with Frontier, USAir, and Northwest. I have a mechanical question: ....
Does anyone know what is causing these noises? Thanks!

An Airbus A320-300 does not exist. You probably mean an Airbus A320-200. Greetz, CanonFreak

Altought I don't know an answer on your question, ....
- When I look @ Airliners, I don't find an A320-300? (I don't think it exists) And; I don't think Frontier have A320's, only A319's...
- Welcome to Luchtzak... Enjoy this wonderfull aviation-site... Greettzzz

Wow, this is quite a hostile site. I have an innocent question about a noise, and already two replies that have nothing (?) to do with my question, ......Perhaps you can find someone else to impress with your particular knowledge

Dear sidestick_rules you know more than we know and you did probably more than all of us did: You said, I have flown on Airbus A320-300 in the US. Great, my friend...

Wow, this is quite a hostile site.... The second reply is even more baffling to me, as the same comment was just made. Perhaps you can find someone else to impress with your particular knowledge;

Dear sidestick_rules your question was in fact:

Wow, this is quite a hostile site. I just want an answer to my question: a series of 5-6 grinding/wrenching/twisting noises come from the floor of the fuselage between the wings. Does anyone know what is causing these noises?

Dear sidestick_rules could you specify these 5-6 noises, by eliminating eg noises in the cargo hold?
Anyhow it was a good idea, to test the other members of the forum before introducing yourself. Your Q was a little bit misleading and somehow ticklish, you will admit.

[Lame]

That was a very short membership........... 8O

There are often many noises at this stage.

The one I always hear on the A320 is just the flaps pulling up harder on the stops after the first engine is on line.

[Avro]

That's indeed a very short membership, but I don't understand your reaction sidestick_rules (if you still read this as a non-member) !!!

Anyway, I agree that there are many small noises like that on a plane, but I don't remember that those were particular to the A320 family

Chris
8)

[sn26567]

Could we all please keep our tempers? This is a forum of aviation enthusiasts, not a boxing ring. I am sure that CanonFreak or Jense did not intend to ridicule sidestick_rule.

Now that sidestick_rules has received an answer to his question by a NW pilot, we all would be very interested to know that answer.

[Fiero]

Still I would like to know what the sound was.
I was thinking about some valve's and ev. flap motor. But I'm not sure.
Therefore I hope that side-stick would be so nice to share the info with us.

[golf1411]

Two weeks ago I flew with an A318 from Paris to Lyon, and I think it made the same noise as described. Passengers all looked up, but the cabin crew didn't move so it will be a normal noise. But I was the first time I heard it, and I flew a couple times with A319 and A320's.
The sound was like or friend mentioned. Could it be the pushback truck that is connecting to the gear underneed our feet I really don't know.

[golf1411]

Now that I am thinking of it, it 's almost the same sound like in Formula 1, when they are changing the tyres. They do it with a machine. The sound is almost similar

[SN30952]

Still I would like to know what the sound was.
I was thinking about some valve's and ev. flap motor. But I'm not sure.
Therefore I hope that side-stick would be so nice to share the info with us.

That is precisely why I asked:
Dear sidestick_rules could you specify these 5-6 noises, by eliminating eg noises in the cargo hold?
It would also give a good indication for what we're looking for, if dear sidestick_rules could give his/her seatnumber, so we could locate the position from where he/she(?) experienced the 5-6 noises.

[sab319]

Two weeks ago I flew with an A318 from Paris to Lyon,

How is teh A318 to fly in?

But to stay on topic , when i flew to MAH last year on OO-TCH of TCAB I heard the same noise just before pushback.

[golf1411]

I have flown twice with A318 F-GUGC. On row 6 and row 15. But you could hear it in the whole planes. I was a little worried because it was the first time I heard this and I already flew a lot of airbusses of the A320-family.
Small story about the A318 F-GUGC. Second time we departed at Lyon at around 9 pm, all the lights in the plane went on and off. Also the sounds of the smoking and seatbelt signs. It was really scary. The computer just went crazy. We had to wait 30 minutes on the taxiway while they were reseting all the computers in the plane. I was happy when I was back in Paris. It's a normal problem for an almost brand new plane Who will tell

[sidestick_rules]

OK! I overreacted as well. Here's the response I got from a retired Northwest pilot:

The sound you're talking about is the PTU (Power Transfer Unit).

This is a bidirectional power transfer unit which enables the yellow system to pressurize the green system and vice versa. The PTU comes into action automatically when the differential pressure between the green and the yellow systems is greater than 500 PSI. The PTU is inhibited during the first engine start.

In "my" company (as in most companies) engine 2 is started first. Once eng 2 is started the PTU detects a pressure difference between the yellow system and the green hydr. system and the PTU starts automatically. (The yellow system is normally supplied by an engine driven pump on engine 2 and the green system is supplied by a pump driven by engine 1.)

So you will hear this strange noise, and indeed it IS a very strange noise, every time one engine is running and the other is not (yet).

You will hear this sound for quite a long time during a power push. (When the pushback is done with a tug connected to the main landing gear. In this case the pilot has to steer the airplane during the pushback via the nose wheel steering.) In this case eng 2 is started at the gate BEFORE the pushback starts. The reason for this is that hydraulic power is needed for the nose wheel steering. In A319/320/321 the nose wheel steering (NSW) uses the green hydraulic power. After the eng 2 is started, hydraulic pressure is provided to the NSW via the PTU and the green hydraulic system. Eng 1 is only started AFTER the pushback is completed because these tugs have limited power and would have a hard time pushing the aircraft back with both engines running at idle.

The PTU is situated near the wing roots. Remember: you will hear this sound whenever only 1 engine is running. If you continue to hear this sound after the taxi starts, you are on UA or one of the few other companies that allows taxi-out on a single engine. The second engine is started during the taxi or at the holding point. This procedure is used for fuel saving.

I hope this answer is clear enough.

The F/A's in "my" company are used to questions from the passengers about this sound. They get this question on nearly every flight.

[luchtzak]

Thanks for coming back to the website sidestick_rules and thanks for bringing the answer to your question on this website!

greetz,

Bart
:rock: