Without being overly touchy your question was
can anyone comment on whether the B757 (uk based) is allowed to operate in freezing rain
I'm not surprised your struggling to get a definitive answer if your not sure what your asking.
As to "are you approved to FLY in freezing rain": the aeroplane is certified for flight in known icing, there is no difference made between icing caused by freezing rain or icing caused by any other means.....however as freezing rain often results in icing which exceedes the capability of the aircraft systems to shed (the definition of severe) you would be ill advised to continue flight in such conditions and if you did continue flying in such conditions it probably would not be for long anyhow.
