SSI Open Water Diver Program Chapter 3 Review

[@timgosling6189]

As a former aviator I thought I'd just add some numbers to the diving and flying thing. If you're flying in a pressurised airliner the pressurisation will allow the cabin to drop in pressure gradually from 1 Bar to the equivalent of that at 7000 to 7500 feet. This keeps everyone in the safe zone for hypobaric symptoms due to low ppO2 which can become a problem above 10.000 ft. But at a pressure altitude of 7500 ft the cabin is still at 0.76 Bar. In the water that would be the same as ascending from 8 ft to the surface. If you choose to travel in an unpressurised puddle-jumper Cessna at 10000 ft you'll still be at 0.7 Bar, a change of 0.3. So compared to the decrease during a scuba ascent from say 60 or 100 ft, it's about a tenth. So not a lot, but it will still bring any excess nitrogen out of solution faster than at sea level and that can cause DCS, especially if you were on the edge of the envelope when you left the water.

[@LakeHickoryScuba]

Thank you for sharing that Tim Gosling, that was very insightful.