Compressed air cylinders are only allowed in carry-on or checked baggage provided that the valve has been removed enabling inspectors to perform a visual inspection to ensure that the cylinder is completely empty, and that there are no prohibited items inside. It no longer suffices to have a tank empty and the valve left open. If the cylinder still has the regulator valve attached, the cylinder will not be permitted through the security checkpoint.

Secondly, airline regulations now stipulate that dive lamps and strobes must travel with their bulbs physically disconnected from their accumulators, which should also be discharged. (See lamp article, in issue #20). The issue at hand being the risk of lamps switching on in flight—or short-circuiting—causing them to get hot and possibly start a fire. However, in some cases, camera strobes are sealed units that cannot be taken apart, which can pose a bit of a problem with over-zealous screeners. To this effect, some strobe manufacturers have issued a statement regarding the safety of bringing their units on planes. Print this statement out and bring it.

It will save you a headache sooner or later.

A friend of mine simply attaches the printout to the strobe where it pokes right into the face of any security screener about to make an issue of it. Make sure that the unit is discharged, too. If you are concerned about weight limitations, you might consider carrying your u/w housing setup. Where the one piece of carry-on luggage policies are enforced, the carry-on regulations do say that you can also bring a camera. Fold the flash arms across to create a carrying handle. Attach a little piece of bubble wrap with a couple of rubber bands, and you have a soft and comfy grip.