What was found
LOUD GRINDING, HIGH PITCH SQUEAL ACCOMPANIED BY TORQUE FLUCTUATIONS. TEAR DOWN INSPECTION REVEALED 3RD STAGE WHEEL EXHIBITED RIM BREAK OUT OF 1.50 INCHES AND .25 INCH OF 2 EACH BLADES. SUSPECT CAUSE OF FAILURE TO BE A STRESS CRACK ORIGINATING ON THE LEADING EDGE SIDE OF BREAK OUT IN REFERENCE TO DIRECTION OF ROTATION, ON THE TRAILING EDGE OF RIM SHROUD AND PROGRESSED APPROXIMATELY ONE-HALF OF CHORDAL LENGTH UNTIL OVERLOAD. POWER TURBINE SECTION EXHIBITS EXCESSIVE KNIFE AND SEAL CONTACT AND BEARING AREA DAMAGE. TOTAL CYCLES 980.