Thud,
the Puma CAFTS (Crashworthy Auxiliary Fuel Tank System) is a smaller version of the Robertson tank fitted to the Chinook. They were introduced just before 2000, but held up due to some concerns over the strength of the floor attachment points. Don't know what their status is now, but I'm as certain as a very certain person that they have nothing to do with this.
ShyTorque - just to be a pedant, it would have been 10-seat (not 12) plus ferry!