|Quoting Readytotaxi (Thread starter):|
The refreshing of cabin air, how does it enter the aircraft?
Does it enter at the front and work its way backwards?
Does that mean that First Class get the "Fresh air" first?
It varies a lot by aircraft. On a Boeing, it enters at the ceiling and flows down to the floor, through the vent grills by your feet into the area behind the cargo sidewalls, then out the outflow valve. Recirculated air is pulled from the mix bay (just behind the forward cargo compartment), mixed with fresh air from the packs, then distributed to all the a/c zones. So, within the passenger compartment, there's no fore/aft difference in air quality. Flight deck is a little different, and has their own dedicated air ducts.
People bitch a lot about air recirculation but, in addition to lowering the load on the packs and saving fuel, it's the only thing to humidify the air. If they ran 100% new air all the time, most people would have terrible headaches from dehydration, have much more problems with illness due to dry mucus membranes, and generally be more miserable than they already are.
I have heard complaints from flight attendants of poor air quality in the aisles of 777's, primarily due to the airflow hugging the signature interior walls and causing low air changeover in the aisles...I have no idea if this is true or not though.