In the case of an arm break, it may actually be the arm stub on the central frame which is broken. In the photo it was a fairly clean break and has been glued with epoxy glue but it may not be as strog as the original. Better to fit a replacement.

Carefully prise off the foam piece on each side containing a GPS antenna and apply it to the new central frame. Make sure the antenna lead is correctly routed.

There is also a sounder on each side which must be prised off and refitted to the new central frame. Again, take care to correctly route the cable.