As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
THE RH LOWER COWLING IS CRACKING WHERE THE EXHAUST HANGER IS ATTACHED. WE HAVE SEEN WHERE THE COWLING HAS A "PUCKER" IN THAT LOCATION AFTER THE FASTENERS ARE INSTALLED. WHERE THAT "PUCKER" IS IS WHERE THE EXHAUST HANGER IS LOCATED. WE HAVE ALSO SEEN ON AT LESS ONE AIRCRAFT THAT THE HOLES WHERE THE EXHAUST BRACKET IS ATTACHED WERE DRILLED WILL A DULL DRILL BIT ALLOWING THE METAL TO HAVE THAT VISUAL APPEARANCE THAT THE BIT WAS DULL AND THE HOLE WAS NOT DEBURRED.