zOwie Omega Discussion Forum

What he's asking about is valid.

Unequal pressure causing the crystal to pop out is the same problem whether it is from decompression in an underwatrer diving bell or in an emergency decompression in an airplane or spacecraft. It doesn't change the mechanics that in the underwater situation, the excess pressure inside the watch is due to helium seepage into the watch -- while in the aircraft situation, it is sudden exposure to the lower air pressue outside the cabin.

The Helium Relief Valve *is* really just an air pressure release valve. It doesn't know or care what gas or gasses make up the excess air pressure in the watch -- it merely releases whatever is there if the internal pressure is significantly over the external pressure.

So if you do expect to be in a sudden decompression situation in an aircraft or spaceship, then if your other immediate worries aren't enough to keep you busy, you should open the HRV to help your watch handle the decompression, too.

This is also why the Speedmaster Professional Moonwatch is not made to be more water resistant than 50 meters. Additional water resistance equals less ability to handle suddent pressure changes. In fact, I have seen documented cases of a Moonwatch crystal popping out on a NASA space mission.