Pace,
I read your comment in post #98:
I have to say that I am amazed that gliders or any other aircraft should be allowed to fly in cloud without a transponder.
as meaning you weren't aware this was possible. I realise it could mean that you were aware (though see your post #115) and amazed as well.
In post #118 Fuji Abound wrote:
No one is flying powered in IMC without a transponder.
and I understood later posts to have pointed out that this wasn't the case.
Apologies if I've misunderstood anyone.
It seems to me that the big concern is not GA v glider/non-transponding power collisions, but airline v glider/non-transponding power collisions. Until fairly recently this risk was managed by keeping airline traffic largely out of class G airspace.
With my lawyer's hat on, I'd think that such a collision might lead to the airline being sued for negligence, or possibly even prosecuted for corporate manslaughter, given the known risk of flying in IMC where there is the possibility of non-transponding traffic being present. GA and glider pilots can be presumed to have voluntarily accepted the risk, but the same can't be true of airline passengers. Whether such a lawsuit or prosecution would succeed I can't say, and I wish I were convinced that the airlines which have chosen to route through class G have reviewed this risk.
More airspace isn't necessarily the answer either, as recent legal developments have opened up the possibility that if a collision between GA/gliders in class G is in part attributable to the funneling of that traffic into narrow corridors, the Government might have legal responsibility for that accident.
It may be that the current oil price jump is enough to limit the growth of low cost airlines, in which case the problem will go away, in the sense that the finger-crossing which IMC pilots have been using for the last 70 years or more will continue to be adequate.
Bear in mind that the risk of a glider/power collision in IMC is, on current numbers, lower than the risk of structural failure - in the last 60 years there appear to have been no such collisions, and there have certainly been multiple cases of structural failure for both categories of aircraft.
I'm not thereby arguing that the risk is so low we should ignore it, merely that it's important to put it in perspective. If I were to retry cloud flying in my glider I'd probably install PCAS, and would try a few initial calls to ATC to see what kind of response I got.
PS to all: On the FLARM issue, 5% is certainly too small to be useful generally. However, last year the number of gliders fitted with FLARM was almost 0%. In two or three years this number could increase dramatically (like credit cards - when I got one in 1974 there was nowhere local to use it, but a few years later there were many takers). This will lead to a further dilemma - I have space for FLARM or PCAS, but not both! Maybe by then there will be a combined unit, which might help us all.