We have installed are the RYAN Tcad 9000b and the BF Gooderich Sky watch on small helicopters .
Ryan is about 15K usd plus instlln ( around 40 hrs ) the BFG a bit higher . The pilots I have spoken to really find it a useful tool.
<a href="http://www.avweb.com/articles/ryantcad.html" target="_blank">http://www.avweb.com/articles/ryantcad.html</a> for a report .