shortfuel, thanks or the great info. I just wish our avionics guys would actually check it when we write it up instead of just saying that if the ND says tilt is "x" then the actual time is "x". Especially since our aeroplanes are getting a bit long in the tooth. Also they don't have the auto tilt function. Also, I typically have my ND range set to 160nm so when flying around 30000' over land there definately should be some ground returns.
Anyway cheers again.