It's a bit hard to work out what you are really looking to do - it appears you want to operate a Mil 18 around Sydney and are looking for details of its sound footprint, and also clues on how to do an environmental study?
Lots of luck. Sydney should be spelt Nimby, it is almost impossible to put a chopper anywhere. If it is for bushfire use, then you might have a chance, but don't expect any government help.
But talk to Steven Cooper and Associates, noise specialists. Not cheap, but the best there is, and fully aware of all things to do with helicopters. Then talk to Dan Tyler of Heli-Consultants (02-9896 5030), he is the Ace From Space concerning helipads and such. Steve's phone numbers in the Sydney book, don't have one up here.
Getting Russian machinery through CASA will give you grey hair, if you haven't pulled it all out before then.
