contact airandground they are somewhere near stafford and have a big inventory of Agusta parts, they may be able to help. They advertise in helidata. Out of interest why do you believe you cannot interchange Bell with Agusta ? I know of many aoc Bell 206,s that are littered with Agusta parts. I know of one that has just been half rebuilt using Agusta parts and is doing public Transport very happily !! As far as i am aware it is only a letter and only enforceable in US and Canada but not here . No doubt the pen pushers will get their way even tho things have been fine for what...37 years or more ??????
