Isn't QSY accepted as a colloquialism?
Accepted by whom?
Personally I don't mind, but the CAA object to its use.
Of course the CAA "object" to it, and so should you! - it is not one of the very few Q codes still in use, therefore it has no official meaning, new pilots/Atcos/Fisos cannot be expected to be aware of its meaning, and therefore anyone using it could create misunderstanding.
2 s