Quote: (Originally Posted by
rigdiver)

Does TSA regs state the cylinder must be completely open? Military types say "less than 300 psi" I just recently travelled to Grand Cayman and had plugged cylinders in my carry on. Only one cylinder (dil) was inspected. Nothing was said about the plug.
The original DOT regulations allow you to travel with up to 45psi if I remember correctly.. The way the regs are written it sounds like they say teh cylinders must be unsealed.. And thats the problem. The intrepretation is up to the individual screener.. The best bet is to leave no room for error and leave the cylinders open..