Thanks guys. Some excellent input here from much more knowledgeable folks.
Yes, this was an unplanned icing encounter and I am fully aware of the 172 non icing capability, even more so now.
There was 4 on board so we were heavy but within limits.
Cloud was patchy for some of the distance and hence IMC/VFR on and off so icing was not an issue initially, it was only when the clag got heavier that it was noticed, and it came quickly, though we knew we did have the height above terrain and melting point below to let it melt off but it wasn't considered an emergency as we were commencing descent very soon after that point so would be in warmer air. I think given any longer in those conditions and we would have descended regardless.
However after landing I noticed melted ice (significant amount) that had fallen off the plane and that is when I realised it may have been more than we could see.
I didn't get time to use the cessna inadvertent icing checklist (truth be told I didn't think of it) but I used only 20 degree of flap and around 75-80 knots on final. It was at the slower end of the flight envelope that thing's seemed to fly differently..!!
Last edited by anderow; 16th Mar 2015 at 11:05.