Thanks for your comments so far.
The part 21 people in the Uk are charging just a little less than applying for a minor change. Its is ok but makes it a very expensive minor upgrade....
Anyone have any more information on the FAA grandfather stc route, surley most of the avionics people want fitting into light a/c pa28, 172 etc. GTX 328, gns 430 were fitted in these a/c well before EASA was born?
