As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(REF 0429084134) DURING ROUTINE INSPECTION, THE ELASTOMER ON (1) FREQUENCY ADAPTER WAS FOUND CRACKED. A NEW SET OF (3) ADAPTERS WAS INSTALLED. THIS IS A VERY COMMON DEFECT FOR THIS PART. SUGGEST A DIFFERENT ELASTOMER FORMULATION BE UTILIZED. AN OLDER PN FREQUENCY ADAPTER HAD A FORMULATION THAT RARELY FAILED. THE MFG IS HAVING DIFFICULTY PRODUCING ENOUGH OF THESE FAILURE PRONE PART TO MEET DEMAND. RETURNING TO THE OLDER FORMULATION HAS BEEN SUGGESTED TO THE AC MFG FOR YEARS WITH O ACTION TAKEN.