You will need to;
Ferry or fly it to the US. A C registered plane in Canada has to be flown by a Canadian pilot, or you can ask Transport Canada to recognize your US license, which would take a month or two.
You also need to find an import broker to handle the import paperwork, it is a simple form to complete but most will charge to use their bond. Transport Canada typically charges $400 for light aircraft to be deregistered, and corresponding paperwork sent to the FAA.
If it is not in annual, you will need to ferry it, and apply through Transport Canada for permission and a Certificate of Airworthiness.
Once it is here, you need to deregister it in Canada, which involves sending a notification to Transport Canada that it has been exported, remove Canadian registration markings, update the ELT, change transponder codes if applicable.
Make damn sure there are no liens in either country, and that the bill of sale clearly states the owner and past owners names in ink with signatures. You do not want to be stuck with a plane with no registration, that is unable to be registered due to paperwork issues.
The FAA and Transport Canada are both bureaucracies. You do not want to get stuck in a back and forth with them while your plane sits.
Probably the most time consuming part. Apply with the FAA for registration like any other plane purchase. Here is where it gets different, it hasn't had a FAA annual/registration recently. First, an IA will need to go over the books with a fine tooth comb, file 337 paperwork etc on modifications that have been done while the aircraft was in Canada. He will need to verify that all AD's have been complied with. This is basically an Annual plus a paperwork exercise.
This should be done with whoever will continue to maintain the plane, because they will get to know the plane and its history intimately well.
- Register It - DAR Portion
The next step once the IA has a chance to look through the books and make necessary filings, is to have a DAR go over the paperwork. This is a Designated Airworthiness Representative.
He will go through the paperwork your IA has done, as well as make sure the plane has all the documentation, supplements, STC paperwork etc in order. His job is mainly on the paperwork side, don't expect him to tear the plane to pieces if its in good condition, but if you have a rust bucket plan on him being more thorough.
The FAA in their documentation says you can place Import on the initial registration application. This is not a quick process, expect at least two months if you are an optimist, and six months if you are a realist.
Ballpark figures on a $100k plane that is in Canadian Annual, and don't quote me;
- Ferry it home $1500-$2500
- Import/Export Broker- Paperwork/Escrow & Bond $1000-1500
- 20 Hours IA inspection- $115 @ $2300
- 20 Hours DAR inspection $115 @ 2300