"Mike Rapoport" wrote in message
k.net...
Don't they fly IFR in IMC without radar separation in the UK all the time?

Without *any* ATC separation, in uncontrolled (class G) airspace. Yes, we
do, though it's worth bearing in mind that it's usually only done when there
is no ATC service or advisory service available.

The issue with flight in IMC is supposedly that you can't see and avoid
other traffic. The converse assumption that underpins the concept of class
E airspace is that in VMC you *will* see and avoid other traffic, even
without help from ATC or TCAS. Success in that game has been shown by both
accident reports and scientific research to be very much less than perfect,
perhaps even less than 50%. Given that the density of uncontrolled traffic
in IMC is likely to be much lower than in VMC, the relative levels of risk
are not obvious.

Julian Scarfe