Except for code sharing I really wonder how much co-operation goes on these days in the cut throat world of aviation.
It would be interesting to know.
In the good ole days at Sunstate when the pride of their fleet was the Irish Concorde (Shorts 360/330), so late 80s to early 90s, I was working for the opposition on the Mohawks. The 330 & Mohawk both ran PT6-45s. Not only did we loan (I'm sure there would have been conditions) Sunstate a PT6 to go into a Shed but our engineers even assisted the build up.