As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
THE BS 1342, LBL 18 CHANNEL WAS FOUND SEVERELY RUSTED WHERE IT ATTACHES TO THE STRUCTURE. DEFECT WAS DISCOVERED DURING A RE-ENGINING MODIFICATION. THIS CONDITION HAS BEEN FOUND ON 38 OF THE 38 AIRCRAFT MODIFIED SO FAR. CONDITION IS PROBABLY CAUSE BY DISSIMILAR METAL AND LACK OF DRAINAGE. NOTE: THE DEFECT COULD NOT BE SEEN WITHOUT REMOVING PART, MAY NEED TO BE X-RAYED EVERY 5 YEARS.