Re: Rain in the plane

From:         Nicolas Ercan Murat <vis@leland.Stanford.EDU>
Date:         09 Nov 94 00:51:24 
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> I am investigating measures to prevent or manage the problems associated 
> with the excessive condensation of water vapor on cold airplane skin and 
> structure (interior) during long, high occupancy flights.  Active 
> dehumidification of the cabin air is not a desirable solution due to the 
> operational drawbacks of the equipment and the risks associated with 
> excessively drying the air (comfort and static problems).  Any novel 
> ideas regarding this topic would be appreciated.

Over Condensation is a problem that both Boeing and Airbus aircraft are faced
with.

When the A340 first came out, their ATA 21 people had to deal with several
condensation problems. These mainly occurred at exit doors and could be
seen at the pressure gauges of the emergency slides. That problem has
been somewhat taken care of. Nevertheless, passengers often see "smoke"
coming out of the vents above the bins. Many think it's a fire at first,
but it's really just air from the AC system.

I've personally been rained on in 747-400. After push back and until we
quite a while after take off, you could hear pellets of ice rolling up and
down the PCU channels. This occurred on both sides of teh 747's A section
(rows 5 and 6 in nose section). The pellets melted of course, and the
woman next to me had to cover herself with the board-magazine, safety card,
etc... The crew was pretty much not surprized by this as they proceeded to
jam cloth napkins in the PCU channel to keep it from leaking on us.

On the subject of dehumidification, it is practically impossible to really
try that.  Boeing as a humidifier in its 747-400 cockpit crew rest. The were
thought of removing it in order to save weight and space, but these were
quickly done away with when humidity was measured to be 0% in the upper deck.


-Bernie