Subject: Why is my nose so dry?

When I fly, my nose turns into a raisin from the low humidity.


Turns out that the culprit is intentionally low passenger compartment humidity. The airplane makers keep the in-cabin humidity at Sahara levels--about five percent.

For two reasons.

1. To minimize condensation which can corrode the aluminum aircraft body from within.

2. To minimize condensation accumulation which can add to aircraft weight.

Some evidence from various airline and Boeing news sites:

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Boeing 787 Dreamliner Will Provide New Solutions for Airlines, Passengers

Passengers will also see improvements with the new airplane, from an interior environment with higher humidity to increased comfort and convenience.

With the passenger in mind, advances in cabin technology are being incorporated to help people feel better during and after a long flight. The Dreamliner will provide higher humidity levels in the cabin and a more comfortable, lower cabin altitude.

Higher humidity in the passenger cabin because of the use of composites (which don't corrode).

Aircraft residual value is likely to be extended on the 787 due to reduced corrosion, and the system is expected to lower fuel consumption and maintain a consistent insulation performance. Boeing says "humidity, when it condenses, also adds weight. So it is in everybody's interest to reduce that."

The system, developed by Nykoping, Sweden-based CTT, will be baseline equipment on all 787s with optional humidifiers offered for flightdeck and crew rest areas, and is designed to maintain a consistent relative humidity level between 10% and 15%, compared with average levels of 3-12% on today's aircraft. . . .

Phil: "This one has a ton of composites, meaning that you don't have to worry about corrosion from humidity. No bleed air is taken from the compressors of the jet engines - it's all onboard electrically powered systems that maintain the environment.

Boeing officials said the benefits of the change are significant; in a nutshell, composite materials weigh less than aluminum, are stronger than aluminum, don't corrode or fatigue like aluminum, and repairs are easier to effect than aluminum. Use of composites also permit the planned changes in the 787 cabin interior, including the use of greater humidity to improve passenger comfort, which wouldn't be possible with an aluminum airplane, Bair noted.

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Message, it appears, is to fly the new 787s when you can and when you cannot, continue to carry that extra water bottle.

Jerry in E TN USA