As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) (2) SEPARATE OCCASIONS NEW UREM38S SPARK PLUGS WERE REMOVED FROM THE PACKAGE AND FOUND TO HAVE CRACKED CERAMIC INSULATORS. TO VERIFY THE PLUGS WERE TESTED AND FOUND TO BE MISFIRING. THE CRACKING IN THE CERAMIC DOES NOT APPEAR TO BE SHIPPING OR MISHANDLING DAMAGE AS THERE IS EVIDENCE OF TRACKING IN THE CRACKS. (TC NR 20080111005)