Have to say that in the fatal accident reports I've read, the pilot
was invariably killed by multiple injuries, not head injuries alone.
That said there have been two accidents in the UK this year where
pilots survived but were left with serious head injuries, and believe
me they're the worst kind of injuries you can have. However I can't
say a helmet would have prevented those injuries - it depends entirely
on how the head was impacted, what by, what energies were involved
etc. My gut feeling is that helmets would be of little use and their
costs (fatigue, possibly reduced vis) too high.

BTW a correctly fitted four-point harness is as safe as a five-point,
although I do recall that the six is the best. As long as you *fully*
tighten the lap strap *first* on a four-point, there should not be any
issues with submarining. I seem to remember that if you do submarine
with a five point, you're going to be left with serious groin injuries
(that's why a six is best), so correct fitting is more important than
variant.


Dan