You can assume that the Chinese have complete engineering plans for any target product, including an aircraft. But having those plans isn't enough to build the

You can assume that the Chinese have complete engineering plans for any target product, including an aircraft. But having those plans isn't enough to build the plane. You needs lots of unwritten know-how to succeed. This isn't just "tricks of the trade", but also knowing about the materials and processes used, how they can fail, where the failure is introduced, and what the known good "beaten path" for a process is. If Boeing were to fire all engineering and manufacturing personnel and completely re-staff, how many years would it set them back? That's why one of the key steps in the China cycle is to get the product built on Chinese soil.