Division (a) The holder of an FSTD qualification certificate shall establish and maintain a system to identify, assess and incorporate any important modifications into the FSTDs it operates, especially:F1

any aircraft modifications that are essential for training, testing and checking, whether or not enforced by an airworthiness directive; and

any modification of an FSTD, including motion and visual systems, when essential for training, testing and checking, as in the case of data revisions.