Bill Daniels schrieb:

In most European countries (including France) a pneumatic vario is
mandatory - and I think its a good idea when I count the times the
saiplane battery went dead in long flights!

Mandating a mechanical vario is an outdated regulation

Whether a regulation is outdated is completely irrelevant if you want to
fly legally.

That said, I doubt "most" European countries require a machanical vario.
Switzerland, for one, doesn't even require any vario at all (except for
cloud flying).

Stefan