I can answer that one: in 1974.

2nd question: forecast icing IS "KNOWN ICING *CONDITIONS*".

Jim Carter wrote:
George,
I've been away for a few years, but when did forecast icing
become known icing without a pirep or physical indications on the
ground? If they are the same thing now days, why are aircraft certified
for "Flight in known icing (FIKI)" and not just flight in icing
conditions?