Certified for known Ice!
Is the question which helicopter is "certified for known ice" at -50?
As we can see it just takes a certain person to push these limits, so it seems the list is endless (unless you look at certfied temps, most being -45C as a lower limit).
I cannot find one helicopter that would be certified in "ice" at -50C.
not Puma nor 92 as temps limit this operation.