jimf671
" ... the main disadvantage is that it requires a number of steps to make it operational during a critical part of flight. The system, currently the most popular used in North Sea, requires the human to physically perform up to six separate steps after the impact phase of a helicopter ditching to make it work. If these procedures are not carried out the system is rendered inoperable and the survivor could drown."
agree 100% with this statement.
If you cannot deploy and prepare before you enter the water, chances are it will not be used. If you do not pop the valve before the valve and bypass on the mouthpiece enters the water, you are going to suck in water, unless the air cylinder discharges and stops the water entering - momentarily. I don't know if once you are in the water if the rebreather will fill with water if the valve is not popped and the bypass remains open - I guess it would. But I'm not sure.
What we have is good if you have time to deploy. No time to deploy - as in this CFIT - a scuba type device you put in your mouth to get air would be much better. Maybe much better for all scenarios. I don't know if they exist.
DB - correct.