Make that last sentence DOES NOT go bonkers....;-) >If you trickle O2 in at the rate you metabolize it and have a CO2 >scrubber, the net cabin pressure should not increase at all. A simple >atmospheric barometer could monitor cabin pressure to make sure your >injection rate does go bonkers. > >Al > -- Alan D. Secor e-mail: secor@btv.ibm.com