JamesG:
It would seem you passed through the frontal system. This happens quite often off the East Coast of Canada. The route from Halifax to Sable Island is about 140 NM. In that relatively short distance, you can cross through several developing systems due to the relatively warm water temp (gulf stream affect) and the cooler temps aloft. Even in the dead of winter you can run into a developing CB.
From the sounds of it, your pitot heat was fully functional and your instruments indicating correctly. The fact that you were tracking to a VOR and experienced a sudden decrease in G/S would confirm it. Especially since it was followed by rapid fluctuations in IAS. The VSI was pegging full up and down, this would definately support convective activity.
You don't have to be in a CB to get this, it could be a TCU or ACC. I have flown for many years (20+) offshore and am still surprised by the B@lls that Mother Nature displays.
This episode should not discourage you from IMC flying, on the contrary, it should inspire you to practice it even further to the point that you will be able to anticipate what The Old Girl has to throw at you and learn to respect your own ability.
Cheers, OffshoreIgor
