I have done a bit of searching round the topic. The Air Accident Invest Board
site
searched for Ditching gives some interesting info:
In the 10 reports produced there was no incident where anyone with a
lifejacket
ditched in a controlled way and did not survive. A PA28 ditched off Guernsey
with two pax wearing life jackets and pilot without. The plane floated
long enough for them to get out on to the wing, inflate the dinghy and for the
pilot to go back into the plane to get all his kit into the dinghy. He ditched
with flaps down and gear up.
A Robin however with fixed gear flipped over on landing. This was a
night
flight which would not have helped, but it could just be that in among these
two incidents there is a fringe message to add to the mono vs trigear debate!
Neither pilot was wearing the life jacket available in the aircraft, and while
one swam to shore the other apparently took off in the wrong direction and
drowned.
They give a graph for 'Likely Survival Time for a Relatively Thin
Person
in Calm Water with no Liferaft'. This compares survival with just lightweight
summer clothing and a survival suit with trousers, long johns, shirt and
heavy pullover. This doesn't seem a totally equable comparison, but does make
the point that the insulation qualities of the survival suit depend on you
wearing
thick clothing underneath it, which from Kevin's account is not too attractive
a proposition. They give the following survival times:
At 5 deg C - S. suit 1 hr 50mins; summer cloths 50 mins.
At 10 deg C - S suit 3 hrs; summer cloths 1 hr
The sea temp in the Channel and Irish Sea at present according to Ant Veals
weather
site is around 12 deg C. I haven't got temps for mid winter but it is difficult
to imagine it will be below 5 deg. Kevins acdvice about survival times
in the Irish Sea in May clearly came from a different hymn sheet than the AAIB
one. In all the AAIB comment and discussion I have waded through there is heavy
emphasis on having user friendly lifejackets, and always wearing them, and
talk also about dinghies but no mention of the desirability of Survival Suits.
In relation to the question of flipping over or trying to jump out
sooner it is worth saying that the guys in the Robin got out without trouble
from the upturned plane, and I think I would prefer my chances of doing that
(as long as I had a good four point harness) rather than risking being
clobbered by some part of the plane while jumping out, or misjudging the timing
and having it land on top of you or immediately in front. I am also not sure
that hitting a wave at 40 kts would be a pleasant experience, and it might just
be enough to tear your life jacket off. The AAIB detailed one instance where
the guy only had a lap strap, hit the water at speed and had head injuries
which stopped him getting out. The website for anyone interested is
www.aaib.dft.gov.uk Regards, David
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