Posted by ChrisM on March 07, 2001 at 11:46:39:
In Reply to: travel...pony tank posted by Hal Williams on March 07, 2001 at 07:01:17:
state that an air cylinder must have less than 40 psi in order to be legal. Don't have the cite but have read it.
THus, you don't have to drain the pony all the way. Of course, that begs the question as to how the airline will know if the bottle is <40 psi without either you demonstrating it w/ an SPG or not having the valve in at all (as well as whetehr the particular employee will know the regs). In order not to be absolutely certain that you won't be pulled aside, then, effectively you have to drain it and pack bottle and valve separately.
I know many people that have left the valve in and claim never to have had a problem. I have done both on one trip recently, valve out on the way and valve in (fully drained) on the return, and no problems on a domestic flight.
ChrisM