Airbus fin and rudder are connected by 7 hinges, 3 of them are also used by the actuators which react to the fin, not to the fuselage.
All 3 Actuators are installed closed together in one gropp at about 40% of the fin height. The rudder front spar broke between upper and middle actuator attach point. These attach brackets are also made of composites mainly from CFRP but also from GFRP in the reinforced area of the actator attach bushing (to prevent galvanic corrosion). The fittings are riveted to the rudder front spar by use of multiple <a href="http://www.huckaerospace.com/products/threaded/hilok/" target="_blank"> HiLok </a>shear pins. (26 HiLoks for the uppermost hinge, don´t know the exact number for the others but it will be some more at the actuator attach brackets). .There is only 1 hinge in the lower rudder area but 3 above the actuators. This lower hinge (let´s call it No. 1) seems to broken at the hinge pin, No. 6 is broken at the fins aft spar attach point. All other 5 hinges failed in the HiLok connection from the composite brackets to the composite ruder spar. This can be seen clearly in the NTSB videotape.
Seems to me the key lies somewhere in this rudder from fin separation and the damage to the rudder in the actuator attach area, but I still wonder what could be the first part that failed.