Committees / Technical Committee/Newsletter/11.06.20 April

Recently, I acted as an expert witness for our local Coroner’s Court on the death of a British diver. The accident happen overseas and it has taken sometime to get the official report from that country’s officials.

I was asked to interrogate the dive record in the deceased personal decompression computer (PDC). Apart from some minor ascent errors that were quickly corrected by the diver there was no indication of anything that could have caused his death.

However, the local experts at the dive site said that the diver called for extra air, from the dive guide, when they were at about 6-metres and he had only about 30-bar of air in his cylinder. At his air consumption rate at that time in his 15-litre cylinder should have lasted about 10-minutes more.
There would seem be three possible causes for his need to seek extra air:

1. When the demand valve (DV) was fitted to the dive cylinder
   and the valve opened, he may have turn the cylinder valve
   back one-half-turn. This is an obsolete practice, but one
   that a number of people still use.
2. The cylinder valve may have rubbed partially closed on the
   overhanging metal work of the wreck he was diving on. Or
3. A combination of the two.
   Whatever the cause the diver suffered hypoxia and died as a
   result.
   

The Take-Home-Message

Always fully open the cylinder valve before you dive, and never turn it back until you are on the surface and out of the water at the end of the dive. Check before going in the water that your pressure gauge is not adversely affected by your breathing.

Safe Diving

Bob Cole
CMAS Technical Director