As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
PREFLIGHT INSPECTION REVEALED THAT HAMMER BLADE HAD CRACKED IN TWO AND THE WEIGHTS AND BLADE WERE CAPTURED BY THE CONTAINMENT BOX ASSY. AS THIS BLADE IS NORMALLY UNDER A 1200 FLEX PER MINUTE OPERATION IT IS EXPECTED TO WORK HARDEN OR FATIGUE OVER TIME. THIS BLADE FAILED AFTER A VERY SHORT TIME SPAN, HOWEVER, AS COMPARED TO NORMAL. SUSPECT A METAL DEFECT OF SOME NATURE. (K)