Posted 1/19/2005 05:06:00 PM by Douglas

What is Boeing doing to keep passengers happy? Increasing the humidity, of course.

When Boeing puts its 7E7 jetliner into service sometime in 2008, passengers will be able to breathe easier, literally. The sleek aircraft, made from corrosion-resistant materials, will have a fuselage that can accommodate much higher cabin humidity -- a boon for frequent travelers.

But passengers likely will place one benefit above all others: increased humidity. The 7E7 could end the stuffy noses, irritated eyes and scratchy throats that now make long flights an endurance test for passengers.

Cabin air in all current jetliners is very dry -- from 5 percent to 15 percent relative humidity, depending on where one sits, how long the flight lasts and how full the cabin is, said Boeing cabin environment expert Dave Space.

Outside air at 35,000 feet averages 68 degrees below zero, Space said -- far too cold to hold moisture, so relative humidity runs less than 1 percent. When that air is drawn into the cabin, it is heated by air conditioning packs in the plane's belly to become breathable. But cabin humidity remains low, humidified mostly by evaporation from food and beverage service and from passengers' exhalation. In first class, where there are fewer bodies, cabin humidity is 5 percent to 10 percent; in a crowded coach section, it's 10 percent to 15 percent. (By comparison, humidity in a relatively dry climate, like Southern California's, is about 30 percent.)

ECLS leads the way.