Before/During Taxi Noise...

[bowler_man]

In real life before or during the taxi, sometimes I hear a loud high-pitched whizzing noise that sounds like a drill drilling in bolts. What is that noise?

Thanks
--Jimmy

[Brett_Henderson]

If you mean you hear it while taxing as a pilot of a small plane, it doesn't matter what it is.. if you can hear it over then engine, you'd better taxi back to the shop..

If you mean as a passenger on a commercial jet, I guess it would depend on what jet it was. I'd guess it's flaps and or spoilers being tested or set for take off. It could be many things.

[Mobius]

That's just the pilot turning on the autopilot pump....
















Maybe not...

[beaky]

I hear all sorts of bizarre noises on airliners: they're like flying factories, with all those gizmos going on and off.  

My guess is it's a hydraulic pump... when I took a ride in a B-17, the pump for the flap actuators was mounted inside the cabin, and it made a noise very much like what you describe. It went off every time the flap handle was moved.

But as Brett said: if you hear anything louder than the engine in a light airplane- don't take off!

[bowler_man]

That's just the pilot turning on the autopilot pump....

Well, the noise will go on, off, on, off, etc. And for a while. Maybe a minute. Someone said it was the pushback truck supplying power to the jet for engine start up.  I thought that might have been it, but before the noises happen, I can hear a sound that sounds like the engines.  Is that just the jet's generators?

Ya, I mean commercial jets...I forgot to specify  :P

[Mobius]

Nevermind, maybe you haven't seen the movie "Airplane".  I was just trying to inject a touch of humor...

http://www.youtube.com/watch?v=hFPYMjUH ... ed&search=

[expat]

In real life before or during the taxi, sometimes I hear a loud high-pitched whizzing noise that sounds like a drill drilling in bolts. What is that noise?

Thanks
--Jimmy

What aircraft where you in at the time?

Matt

[Craig.]

cargo doors closing and locking.
Flaps being set
Bambi becoming someones sliced meat sandwhich.

[Ells_228]

[quote]Nevermind, maybe you haven't seen the movie "Airplane".

[matt2190]

Roger roger.....Over over

Whats our vector victor.

[Tweek]

Don't suppose it sounds like this?

http://www.youtube.com/watch?v=Auvc_0NS6v0

Of course, it won't be an AVPIN starter on a modern airliner, but something similar perhaps?

[bowler_man]

Nope, it doesn't sound like that.

And I was in an A320 and A319.

[expat]

Nope, it doesn't sound like that.

And I was in an A320 and A319.

Most likely you heard the flap motor(s) driving the flaps out and that goes for most airliners. Above the noise of cabin conditioning air, the safety video, what is being said over the PA and the engines themselves, about the only thing loud enough to be heard over this is a hydraulic motor. If you are stood next to one (an I am all too often) the noise trieds very hard to split your head in two! Also at the same time you can often feel an amount of resonance through the aircraft structure. They are extremely powerful, for example on the 737, they are bolted down as with all components, but also they have large steel cable straps over them in case the bolts ever fail, they would thrash themselves and anything close by to death.

Matt

[Jakemaster]

Nope, it doesn't sound like that.

And I was in an A320 and A319.

Most likely you heard the flap motor(s) driving the flaps out and that goes for most airliners. Above the noise of cabin conditioning air, the safety video, what is being said over the PA and the engines themselves, about the only thing loud enough to be heard over this is a hydraulic motor. If you are stood next to one (an I am all too often) the noise trieds very hard to split your head in two! Also at the same time you can often feel an amount of resonance through the aircraft structure. They are extremely powerful, for example on the 737, they are bolted down as with all components, but also they have large steel cable straps over them in case the bolts ever fail, they would thrash themselves and anything close by to death.

Matt

Exactly what I was about to say.  The flap motors.  On certain planes it sounds a lot louder than you'd think it would, but you can definatley hear it!

[expat]

Nope, it doesn't sound like that.

And I was in an A320 and A319.

Most likely you heard the flap motor(s) driving the flaps out and that goes for most airliners. Above the noise of cabin conditioning air, the safety video, what is being said over the PA and the engines themselves, about the only thing loud enough to be heard over this is a hydraulic motor. If you are stood next to one (an I am all too often) the noise trieds very hard to split your head in two! Also at the same time you can often feel an amount of resonance through the aircraft structure. They are extremely powerful, for example on the 737, they are bolted down as with all components, but also they have large steel cable straps over them in case the bolts ever fail, they would thrash themselves and anything close by to death.

Matt

Exactly what I was about to say.  The flap motors.  On certain planes it sounds a lot louder than you'd think it would, but you can definatley hear it!

Especially if you happen to be sat over the point that they are installed.

Matt