Originally Posted by JohnRPollard
I always inflate mine before boarding. I doubt I'd have the presence of mind to pull the chord if the plane was going down.
Actually, you are supposed to wait until the plane has crashed into the ocean, and you are out of the fuselage and in the water to inflate it. If you don't, you will not be able to swim out of a sinking fuselage because you will be stuck to the ceiling due of the flotation of the life vest.
As to the OP question, I haven't a clue.