BR715-A1-30
Topic Author
Posts: 6525
Joined: Thu May 30, 2002 9:30 am

Air Whooshing Through The 717s Overhead Bins

Tue Sep 10, 2002 9:22 am

Hello All of you Technical people. How are you?

My question today is about the 717... Again.

I noticed when the pilot throttles up, There is a sound that sounds like Air Whooshing right through the overhead bins. The pilot will advance the throttles, and you will hear the engine accelerate, and at the same time you will hear the WHOOOOOSSSSSHHHHHHHH.


Also, I have noticed that while sitting at the gate, there is this whining sound that goes like "EEWMMPH" every 5-6 seconds. It sounds like it is coming from the Cargo area. Can anyone explain this?


Thanks for your help.
Puhdiddle
 
cdfmxtech
Posts: 1319
Joined: Wed Jul 05, 2000 11:37 am

RE: Air Whooshing Through The 717s Overhead Bins

Tue Sep 10, 2002 1:37 pm

Probably the sound of the packs (air conditioning) getting more air as the engines accelerate.

The sound u hear the gate is probably the hydraulics. If the B717 hydraulic system setup is the same as the Dc9/Md80 series...the that is the sound of the elec xfer pumps
 
747forever
Posts: 141
Joined: Sun Jun 08, 2008 5:00 pm

RE: Air Whooshing Through The 717s Overhead Bins

Wed Sep 11, 2002 6:24 pm

yup, thats it, i noticed the same thing on the 747, on the descent, every so often the engines would spool up, and as they did there would be an increase in the wooshing sound of the air conditioning, obviously due to the packs getting more bleed air as the engines turn faster

Cheers,

Jeff.
 
AA737-823
Posts: 4956
Joined: Wed Mar 01, 2000 11:10 am

RE: Air Whooshing Through The 717s Overhead Bins

Thu Sep 12, 2002 11:45 am

That sound is strange, and really worried me the first time I heard it. It is the hydraulics. You can hear it on any MD-80 or 717 flight, any airline. It's a grinding, moaning sound at first when they power up the hydraulics at the gate, then it goes to exactly as you describe it...

Randall
 
brons2
Posts: 2462
Joined: Tue Sep 25, 2001 1:02 pm

RE: Air Whooshing Through The 717s Overhead Bins

Fri Sep 13, 2002 2:31 am


The sound u hear the gate is probably the hydraulics. If the B717 hydraulic system setup is the same as the Dc9/Md80 series...the that is the sound of the elec xfer pumps


I have heard this be very loud on some AA MD80s. It's quite annoying when you're on the ground.
Firings, if well done, are good for employee morale.
 
cdfmxtech
Posts: 1319
Joined: Wed Jul 05, 2000 11:37 am

RE: Air Whooshing Through The 717s Overhead Bins

Fri Sep 13, 2002 2:52 am

The MD80 hydraulic sound at the gate (using auxilairy hyd) is not like most aircraft. It is not a steady whine.
The sounds breaks unsteadily. It almost sounds like something is wrong, which was what I thought the very first time I worked the aircraft.
 
BR715-A1-30
Topic Author
Posts: 6525
Joined: Thu May 30, 2002 9:30 am

RE: Air Whooshing Through The 717s Overhead Bins

Fri Sep 13, 2002 8:40 pm

It's a grinding, moaning sound Yep, That is the sound. When it first started, The lights flickered off, and back on. So it must be the hydraulics.

Thanks Everyone,

And about the Air Whooshing. I am going to go with the A/C Packs Theory. Nothing else for me to go on unless some troll is up in the overhead bin that has incredibly large lungs  Smile
Puhdiddle
 
atlamt
Posts: 244
Joined: Thu Sep 13, 2001 12:15 am

RE: Air Whooshing Through The 717s Overhead Bins

Sat Sep 14, 2002 12:45 am

The reason you hear the sound coming from the overhead bins is because of the layout of the air distribution ducts. The main line is running along the top of the cabin. This main duct starts just forward of the aft door and runs the length of the cabin stopping just short of the cockpit door. The main line through a series of ducts spaced every few feet feeds two smaller ducts, one on each side of the cabin just above the bottom of the overhead bins. These line provide air to the gasper vents above your head.

As mentioned before as the engines spool up more bleed air is sent to the packs which causes more air to be introduced into the system. This is what causes the sound of the air whooshing to increase and hopefully I explained why it comes from the overhead bins.

The link below is a picture of an MD88 during overhaul. The picture quality isn't the greatest but it will show you where everything is.

http://www.imagestation.com/mypictures/inbox/view.html?id=4249313847&url=http%3A%2F%2Fwww.imagestation.com%2Fpicture%2Fsraid31%2Fpd6c129c1dfbfadd5d8d95f588d247224%2Ffd476237.jpg&caption=md88cabin

Fwd to MCO and Placard

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