Good point, not being an ejection sat type I forget about that design criteria -- makes it a bit more of a compromise than other systems.

When I did my qual I noticed that some of the collar types do not play well with helmets. When I inflated one of the PFD's you'd find under your seat on a civilian airliner, it caused a lot of upward pressure on the chin strap. Not as bad with the LPU-32/P.
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Better is the Enemy of Good Enough.
Okay, what’s your point??