As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
UPON ENGINE DISSASSEMBLY THE DIFFUSER WAS FOUND TO EXHIBIT A SEPARATION OF THE AXIAL WELD OF THE PRESSURE CASE. THE FAILURE WAS INITIATED AS A FATIGUE CRACK WHICH RUPTURED AFTER REACHING A 3.00 INCH CRITICAL LENGTH. CAUSE IS ATTRIBUTED TO LOCAL MATERIAL THINNING IN THE WELD HEAT AFFECTED ZONE. TO ADD AN ANNEAL CYCLE AND TO REDUCE THE ALLOWABLE WELD MISMATCH IN THIS AREA.