[i] Well, as we reported earlier the chief executive of the Dutch airport where the flight departed says 27 Australians were on board. (ABC news)
[ii] There was where Vadinho used to sit on the wall, at his feet the sea dotted with fishing skiffs. (Dona Flor and Her Two Husbands, translated by Alfred A.Knoptf)
Someone says where of [i] is (relative) adverb, another one says preposition (CGEL,p.1050), and another one says adjunctizer (by Bas Aarts). Okay aside from whatever names they call it, there is antecedent in [i], and there isn’t any in [ii] - In the latter case, antecedent is freed or fused; ‘where’ of [i] means ‘from which’, ‘where’ of [ii] means ‘the place in which’. This is the difference between the two, isn’t it?