What was found
DURING CRUISE AT FL 350, RT ENG HAD A RAPID RISE IN ITT AND VIBRATION LEVEL. CREW SHUT DOWN ENG. ENG REMOVED TO DETERMINE CAUSE OF FAILURE ANDTO REPAIR. DISASSY REVEALED ON LOW PRESS, 4TH STAGE COMP BLADE, P/N 3072402-1, 'MISSING' FROM COMP ROTOR. BLADE DEBRIS CAUSED EXTENSIVE DOWN STREAM DAMAGE. BLADE RELEASE CAUSED BY CRACKING OF THE BLADE DOVETAIL, WHICH IS RESULT OF AN UPSTREAM EXCITATION FROM 4 DIFFUSER STRUTS AFT OF LP COMP, 4TH STAGE STATOR ASSY. CRACK ALLOWED BLADE TO EXIT DISC DOVETAIL. ALLIED SIGNAL ISSUED SB TFE731-72-3483, WHICH INCORP NEW 4TH STAGE STATOR, P/N 3074555-8. NEW STATOR HAS ONE ADDITIONAL VANE (83 TO 84) AND EXIT ANGLE CHANGE IN 54 LOCATIONS COINCIDENT WITH 4 DOWNSTREAM STRUTS.