sounds like pilot error - you hit the T/r on the floor. those pitch arms break VERY VERY easily but also for a good reason and they are kinda expensive $5.50 a pair. i've CAed mine back together almost 5x each side no problem = free fix.

alternative:
upon putting on the trex XL pitch control system which is rock hard compared...when you hit that thing instead of breaking a stupid pitch link - you tweak the t/r shaft, break the whole slider assembly, and maybe even the aluminum hub if not stripping the tail belt or pullies. that's probably $20 worth of damage. im back to the stock ARK system for now until i get one of the new trex SE system.

now that is like a "crush zone" if you think about it. you must be careful when assembling it also. using a good set of ball link pliars to snap it in or out as the plastic is weak there. who knows...what happned in your case. these things arent toys, theyre precision models.

even if you just Nicked the T/R something will happen. the X400's tail system is like a 5:1 ratio. it's spinning VERY fast and has a lot of inertia in it. if you did that in the shogun youll know what happens - input gear or hex end will round almost indefinitely. belt drives are NOT invinsible.