In 2010, RBC Avion had a 1.25x AA transfer promo. In 2011, there was a 1.3x AA transfer promo. Otherwise they transfer 1:1.
Why waste your time even thinking about transferring BA to AA (which, even if there was a way to transfer between the two, would likely result in some loss of value), when there is a way to transfer RBC Avion direct to AA?