The 717 fresh air system...

[mduell]

I read a few of the enormous number of articles posted by haze in the last two days, and I'm wondering if one of the 717 mechanics can explain the "fresh air system" that always gets mentioned about the 717?

I'm just a GA guy, but I was under the impression that all big jets continuously cycle air from the outisde through the cabins to minimize the duration of unpleasant odors (like the guy next to you and the airplane food not agreeing with each other).

[jetmech717]

http://www.iht.com/articles/92211.html

On jets built before the 1980s, airlines used to provide 100 percent fresh air during flights, guaranteeing that the air in the cabin was frequently replaced. But since the 1980s, airplanes have operated on a mix of fresh and recirculated air, which is passed through the cabin after being heated and cleaned. Boeing said that the filtration systems on its planes can clean air to the standards of a hospital clinic. It maintains that recirculated air is better for passengers than fresh air, because it contains more moisture than the dry air outside an airplane cabin in flight. Airlines also save about $60,000 per aircraft each year by using 50 percent recirculated air. "The risk of contamination is no greater than being in a confined area with other people, and the risk on airplanes is actually a little lower because of the air filtration," said Mary Jean Olsen, a Boeing spokeswoman. All of the planes that Boeing delivers to airlines, with the exception of small Boeing 717 jets, are now equipped with filters. But the Association of Flight Attendants says airlines do not always maintain the filters properly.

Basically the 717 keeps pumping in new air and letting old air out through the outflow, were other planes may leave the outflow valve shut all the way and recirculate the air to keep cabin pressure.

[mduell]

So the air inside the 717's is pretty dry?

[jetmech717]

I think it is. Everytime I have to fly I feel like the air is drying my nose out. This has always been a prob in aviation. The air in the cabin comes from engine bleed air, and it gets HOT in the engine, thus taking out all the mosture. They can not find a light and cost effective way to help keep this from happening?????? This gets into engineering and is out of my hands.

[haze]

Yes indeed, I've taken it upon myself to proactively balance the content of the AirTran portion of this site so visitors can come away with a fairer, more educated, an better informed understanding of the airline. Previously, everyone was simply "reacting" to the negative slant dbaker was offering, and from now on I'm going to make sure the whole story gets told. I've posted a grand total of 3 articles "in the last two days." Not exactly "enormous" by most standards. Now if you meant to say in the last "four" days, then yes I've posted a grand total of 10 articles. Still not exactly "enormous", but hey I had a lot of "balancing" to do

Every time I fly on a 717 the air does seem a tad dry. But being from Georgia I've had to suffer through sweaty, frizzy, muggy, stagnant my entire life so I actually enjoy the cool dry air. But I'm sure most airlines' filtration systems, like the Association of Flight Attendants have said, aren't maintained very well or properly so I like the assurance of 100% fresh air ALL of the time. I've noticed far fewer body odors of every sort on the "fresh air" 717 than in the past on 737, 747, 757, 767, 777, DC9, MD80, and Canadair RJs. I haven't tried out JetBlue's A320s yet, but I may fly them ATL to JFK next March just to check them out. Please forgive me AirTran, it's only research