As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
SECURING/ATTACHING TAB WELDED TO EXHAUST RISER ASSEMBLY FOR CYLINDER NR 4 BROKE OFF CAUSING SUDDEN LOSS OF ENGINE MANIFOLD PRESSURE AND POWER RESULTING IN IMMEDIATE LANDING OF AIRCRAFT. (NR 4 CYLINDER RISER SEPARATED FROM NR 6 RISER WHEN TAB BROKE.