As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
REMOVED THE #2 AND #4 CYLINDER INTAKE AND EXHAUST ROCKER COVERS FOR ROUTINE GASKET REPLACEMENT. UPON INSPECTION OF THE VALVE ASSEMBLY, I FOUND THE LOCKING TAB WASHER P/N: 501868, FOR THE CYLINDER ROCKER ARM SHAFT HOLD DOWN BOLTS TO NOT BE BENT INTO THE LOCKING POSITION. THIS COULD CAUSE THE ROCKER ARM SHAFT HOLD DOWN BOLTS TO BACK OUT LETTING THE ROCKER ARM PULL OUT OF POSITION CAUSING CATASTROPHIC ENGINE FAILURE.