

English is notoriously awful regarding orthography vs pronunciation. I actually thought you meant something that rhymed with Bach just looking at the name with a longer ‘a’ for some reason (which is weird since vowel length isn’t phonemic in English).
Edit: you probably also could have said “hard a” or something since it probably literally thinks ‘long a’ means ‘hold the a sound for a longer duration’ (which makes sense to me)
I think a/c is mostly (entirely?) a north-american naming convention. It’s been “aircon” in the other places I’ve lived in traveled.