What MAD is good at picking up is a change in the density/amount of iron/steel material due to its magnetic characteristics. The amount of iron/steel plays a big part in making a big enough mag field change to pick up: signal to noise ratio issue. (I'd need to look up a few bits from long, deep memory, but I do recall there being degaussing ranges our subs used to run through to reduce mag signature ... memory very fuzzy). HY 80 and HY100 steels were what a lot of US subs were built with, but that's very old news. I think they have more exotic alloys in the newer stuff.
Russian Alpha class, all Titanium, was not something MAD would pick up ... did find a Tango once, though. Good day for us.
As to A330, I presume the engines have lots of steel alloys in them, which is what I was hoping for with that F-16. Again, more than an order of magnitude less steel/iron than a standard submarine ...
Just out of curiousity, has A330 got titanium in the wing boxes?