The A330 was/is the anomoly, not viceversa. 72/72 now 272/273 have been 767 variants since 1997 when the route went nonstop - previously it was a 727 to FRA and then whatever, 767, A310, L1011 to your US destination. Other than operational day to day swaps, the only time that there has been an aircraft other than a 767 variant on this route wre this past summer as noted and one season IIRC five years ago when they were flying horrible un-modernized NW configured A330's.