As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) A TURBINE DISK MACHINED, AS A TRIAL, TO AN UNAPPROVED PROCESS WAS ERRONEOUSLY ASSEMBLED INTO A MODULE AND SUBSEQUENTLY BUILT INTO ENGINE CA0043 CURRENTLY ON LEARJET 60-103. THE UNAPPROVED PART WAS REPLACED. THIS IS AN ISOLATED CASE AND NO OTHER DISKS ARE AFFECTED.