Yesterday, I took a flight on an Airbus A319 from Amsterdam. During the wait to push-back, and after push-back, and all the way along the taxi-way to the furthest runway, 36L, where I was sat, right above the main gear, I kept hearing these worm-gear like repetative noises, which were distinct from the flaps worm-gear drives, as those were selected before the taxi-out. These noises, continued for at least 10 minutes into the long taxi before a northerly departure, then stopped. Same thing happened inbound as we cleared the runway exit and neared the terminal gate.

Anyone any idea what these noises are? Am intrigued.

 

Fsl or  Aerosoft  version

14 minutes ago, pete_auau said:

Fsl or  Aerosoft  version

Neither. It was a real-world flight!

Could be this:-

 

http://www.askthepilot.com/questionanswers/the-barking-dog-airbus-noises/

 

 

Could be the electrical hydraulic pump, in big airports many airlines taxi with only one engine for fuel saving.

25 minutes ago, nachezdc9 said:

Could be the electrical hydraulic pump, in big airports many airlines taxi with only one engine for fuel saving.

I think you have hit it on the head, because I was sure that I heard the other engine start-up during that long taxi to 36L, and thought of the fuel savings options for a lo-cost airline, and my first instincts as passengers looked enquiringly and commented on that noise, was that it was the electrical hydraulics, which explains the inbound taxi to the gate whirring noises I also heard.

Thanks guys for the replies.Appreciated. Just wanted to make sure my hunches were not off-beam.

1 hour ago, Major_Bloodnok said:

Could be this:-

 

http://www.askthepilot.com/questionanswers/the-barking-dog-airbus-noises/

 

 

Yep, that's the PTU or Power Transfer Unit which you will typically hear during single engine ops. The first time my kids flew with me as their captain, many years back, they were convinced I had bought them a Golden Retriever, and he was in the cargo hold waiting for them. That made for a long ride home from the airport, when they realized I hadn't, although they did end up getting the dog a few weeks later!

13 minutes ago, busdriver said:

Yep, that's the PTU or Power Transfer Unit which you will typically hear during single engine ops. The first time my kids flew with me as their captain, many years back, they were convinced I had bought them a Golden Retriever, and he was in the cargo hold waiting for them. That made for a long ride home from the airport, when they realized I hadn't, although they did end up getting the dog a few weeks later!

Funny that you should mention a Golden Retriever, because that is what it more or less sounded like, a dog in the far distance 'barking' repeatedly !!

Thanks for the elaboration.

You are welcome!