I Have over 2000 hrs in Seneca fives so know them reasonably well. These are certified into light icing. I note the poster reported moderate ice. Was this infact moderate or his interpretation of moderate?
Is there a definition of 'moderate' that doesn't have a highly subjective metric?
It is implicit in the definition of "light icing" that brief exposure is not a "problem":
The rate of accumulation may create a problem if flight is
prolonged in this environment (over 1 hour). Occasional use of
deicing/anti-icing equipment removes/prevents accumulation. It
does not present a problem if the deicing/anti-icing equipment is
used.
But for "moderate icing"
The rate of accumulation is such that even short encounters
become potentially hazardous and the use of deicing/anti-icing
equipment or flight diversion is necessary.
So what do you do in an aircraft with de-ice that is "certified into light icing"? Does the de-icing suddenly stop working after an hour? If it can cope with the ice by use of the available equipment, is it "light" or "moderate"?
A History and Interpretation of Aircraft Icing Intensity ... has some very interesting perspective.