Brad_Horn
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Navy Clear on Causes of Physiological Events in Pilots; Final Recommendations Released for PE Mitigation - USNI News
Noting hypoxia is recorded as the highest % causation of rebreather fatalities the above link, whilst from a dis-similar origin, might have enough similarities to be of interest to rebreather divers. In particular the correlation with hypoxia like symptoms being attributed to high WOB. Something that is not yet optimized in most rebreathers on the market.
"On the oxygen side, the air produced by OBOGS was found to be clean, and though aviators showed symptoms of hypoxia, it turned out they didn’t actually have hypoxia – where the body’s tissues are deprived of sufficient oxygen.
Instead, “even under benign conditions, the act of breathing highly concentrated air from a closed-loop system while encumbered by bulky flight gear in a cramped cockpit is not easy. And in the dynamic environment of a fighter cockpit, we also add to the equation temperature variance, exposure to continual changes in Gs and pressure, all while managing an overwhelming amount of sensory input. All this amounts to increased what we call ‘work of breathing.’ Over time, increased levels of work of breathing can lead to fatigue and changes in breathing patterns, leading to inefficient gas exchange, and many of those symptoms look a lot like hypoxia,” he said.
“Further, the F-18 RCCA team found that ‘work of breathing’ could also be affected by improperly fit or worn flight gear, malfunctions in the oxygen mask, and malfunctions of the OBOGS unit itself,” Luchtman added. Though OBOGS has an alert system to warn pilots if it malfunctions, there is no such alert for flight gear and masks that don’t fit, aren’t being worn properly or have experienced some kind of malfunction. Luchtman said efforts to create some kind of gear alert system are immature at this point, but that the Navy is trying to explore this avenue to protect pilots against failures in the gear meant to protect their bodies."
Noting hypoxia is recorded as the highest % causation of rebreather fatalities the above link, whilst from a dis-similar origin, might have enough similarities to be of interest to rebreather divers. In particular the correlation with hypoxia like symptoms being attributed to high WOB. Something that is not yet optimized in most rebreathers on the market.
"On the oxygen side, the air produced by OBOGS was found to be clean, and though aviators showed symptoms of hypoxia, it turned out they didn’t actually have hypoxia – where the body’s tissues are deprived of sufficient oxygen.
Instead, “even under benign conditions, the act of breathing highly concentrated air from a closed-loop system while encumbered by bulky flight gear in a cramped cockpit is not easy. And in the dynamic environment of a fighter cockpit, we also add to the equation temperature variance, exposure to continual changes in Gs and pressure, all while managing an overwhelming amount of sensory input. All this amounts to increased what we call ‘work of breathing.’ Over time, increased levels of work of breathing can lead to fatigue and changes in breathing patterns, leading to inefficient gas exchange, and many of those symptoms look a lot like hypoxia,” he said.
“Further, the F-18 RCCA team found that ‘work of breathing’ could also be affected by improperly fit or worn flight gear, malfunctions in the oxygen mask, and malfunctions of the OBOGS unit itself,” Luchtman added. Though OBOGS has an alert system to warn pilots if it malfunctions, there is no such alert for flight gear and masks that don’t fit, aren’t being worn properly or have experienced some kind of malfunction. Luchtman said efforts to create some kind of gear alert system are immature at this point, but that the Navy is trying to explore this avenue to protect pilots against failures in the gear meant to protect their bodies."
