View Full Version : What's buzzing during A319 takeoff?
As a passenger in an A319, I hear a loud low-frequency buzzing sound during takeoff and climb. There is also a little bit of wind noise, and faint engine whine, but this buzzing is much louder. What is it?
It sounds as if it comes from up front and is kind of like the noise from a motorscooter engine or 50/60 Hz audio hum, but more raspy. As the plane levels off and picks up speed, the buzzing goes away and the wind noise becomes much louder.
Maybe I'm not asking the question correctly. Anyway, thank you for considering my question.
PaperTiger
5th Aug 2002, 23:06
Since none of the experts have chipped in, I'll hazard a guess.
The engines on all the A320 family produce a buzzsaw noise at takeoff power. Perhaps this is more noticeable on the A319 due to the shorter fuselage not absorbing as much of the vibrations.
I've not ridden a 321 yet, but if my 'theory' is correct they should be quieter than the 320s.
I assume they all come with the dog that barks during taxi :D
Rollingthunder
6th Aug 2002, 23:29
Buzzsaw is the term. Less insulation on the baby high-bypass engines so more noise in take-off and climb power. Think of it as a comforting noise.
ExSimGuy
10th Aug 2002, 13:43
Way, way back, when I was building Flight Sims, I first came across the "buzz saw" on the (simulated) sound system for the 747 and it came in at higher power levels.
That was one of the early high bypass engines, and the sound is characteristic, although I'd agree it's more noticable on the more modern jets than the old 747 Classsic.
NO CARRIER
10th Aug 2002, 23:39
I read somewhere (here?) that the noise you hear is because the tips of the blades in the engine go supersonic. As others have said the high-bypass engine is used and it has longer fan blades. I also first noticed the noise on the Airbus A319.
Thank you for the responses. I agree with Rollingthunder that it is a comforting noise.
The answer that the buzzing noize comes from the engines brings forth another nagging question. What is the mechanism in the engines for generating the buzzing noise?
With engines spinning at a high RPM, I'd think only the high-pitched whine would be heard. It's like it is a fuel pump, or bearings going out, something out of balance, or the engines' noise beating against each each other if they are not in sync (like the Cessna 310 my neighbor used to fly). But, I know it is none of those things.
MarkD
15th Aug 2002, 16:43
I've heard it [deafening] on a BA 320-100 [ex BCal] and [quieter] EI 321.
Although I was a little worse for wear boarding the BA flight :D
gofer
18th Aug 2002, 03:33
I think you'll find that its power & flaps related - ie: starts not so much landings. Check that out next time.
One thing you may also notice is the juddering on the 321 just after takeoff - used to be very noticeable on the first Air Inter 321's - seems less serious on the newer planes.
The 321 in really rough air is more prone to pitching and the 319 is yaw prone - not surprising really if you think of the aerodynamics.
Any comments from the Engineers & Toulouse ??:D
ExSimGuy
18th Aug 2002, 03:55
Gopher, - as I recall from the early 747s, nothing to do with flaps - it came in about half way up the power curve and was roughly proportional from there on. Purely an engine noise and nothing to do with airframe config.
Maybe the enginers don't read this section of the board:( I did ask a couple of my mates at the weekend, but none of them works on heavy commercials (rotorheads and air force singles only) so no joy there