Ditto. How high above the water does the Army recommend executing this jump? Estimating your height above the surface can be difficult. Jump too high and you're toast.

Problems with jumping out prior to impact is that your water entry is now a direct impact with the water at a speed possibly higher than the aircraft's, but short of terminal V; at least in the aircraft you can somewhat control your impact and minimize damage to your person.

By jumping, rather than being strapped inside an airframe that will absorb the impact, you get to take the water impact directly up your nose at a velocity of gravity's choosing -- I'd guess a fairly high velocity. I'll pass. . .

Whomever in the Army made that recommendation must not have spent too much time running the numbers. Underwater egress training is something every Naval aviator has to do.