LLC tax question

My husband and I started an LLC towards the end of 2007 in order to buy a small used airplane (Cessna 172) and lease it to a flight school. Towards the end of 2008, we had some major repairs including an engine overhaul and a new propeller. When figuring depreciation, do the costs of these repairs get added to the airplane, which was put into service in 2007, or are they considered a new asset first put into service in 2008?

I’m pretty sure they get added to the basis of the airplane and are not new assets, but I’ll look in the big ol’ book of tax knowledge at work tomorrow and follow up (this post is really just a bump).