As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
PILOT REPORTED HIGH MAG DROP ON LEFT MAG. RUN-UP INDICATED NEARLY COMPLETE MAG FAILURE. DURING DISASSEMBLY, A LARGE AMOUNT OF DUST WAS NOTED IN THE AREA OF THE CONTACT ASSEMBLY AND CONTACTS WERE BARELY OPENING. THE CAM WAS FOUND SEVERELY WORN. NO REASON FOR THE UNUSUAL WEAR WAS NOTED.