Peter wrote:
The purpose of my original Q here was to see how it works in the USA.
I guess it works because the US has plenty of instrument approaches
available, whereas most general aviation airfields in Europe don't
have an IAP so many pilots just do it themselves.

Most private airports in the US (these outnumber the public airports)
do not have instrument approaches. A few do, but this is an expensive
luxury. There are also more than a few public use airports without
instrument approaches. Pilots based at such airports have basically
two options, and both are in common use. What I mean by this - I know
lots of people who use these options, and they know lots of people -
and nobody has been busted. Also, no insurance policy that I have ever
seen excludes coverage for FAR violations. I've known people to have
accidents with expired BFR's (not legal to act as PIC) carrying
passengers, and the insurance still paid.

So what are the options?

Those that are located reasonably close to a public airport with an
instrument approach will generally fly that approach, cancel IFR, and
scud run to their actual destination. If the conditions are too poor
for this, they will simply land and wait it out or get a ride home.
Since we don't have large landing fees anywhere but a few of the major
internationals (we consider anything over US$20 large) it's not a huge
problem.

This practice is not actually prohibited, but the legality is about the
same as any scud running - minimum altitudes, visibility and cloud
clearance requirements, etc.

Those that are not located reasonably close to a public airport with an
instrument approach are generally quite centrally located in the middle
of nowhere. There is no official weather reporting anywhere close.
There might be an automated system, but those are known to be
notoriously unreliable. FAA inspectors are almost never found at these
airports - and at many private airports FAA inspectors only show up in
extremis, and only in groups - a single inspector might disappear
without a trace. So pilots do exactly what they do in the UK - make up
their own approaches. This is quite frankly illegal, but ATC cares not
a whit once the pilot reports the airport in sight and cancels IFR, so
really the only way to get busted is to have someone report you to the
FAA - and the sort of people who do that don't last long at that kind
of airport either.

The system works not because the rules allow for this, but because the
rules are generally not enforced.

Michael