AN MD80 IN CRUISE AT FL370 DECLARED AN EMER AND DIVERTED DUE TO FAILURE OF THE R ENG N2 ROTOR.

Narrative

WHILE CRUISING AT FL370; JUST S OF TERRE HAUTE; IN; ACFT X SUDDENLY MADE A SLIGHT YAW TO THE R. THE AUTOPLT AND AUTOTHROTTLES WERE DISENGAGED AND AN ASSESSMENT WAS MADE OF BOTH ENGS. THE L ENG HAD NORMAL INDICATIONS. THE R ENG HAD NO OIL PRESSURE AND NO N2 RPM. THE R ENG EGT DROPPED CONSIDERABLY AND THE N1 RPM WAS WIND MILLING. OIL QUANTITY FOR THE R ENG WAS OVER 12 QUARTS (NORMAL). R ENG OIL TEMP WAS NORMAL. NO VIBRATION WAS FELT. AN EMER WAS DECLARED AND A DSCNT WAS MADE TO FL220. THE ENG FIRE/DAMAGE/SEPARATION CHKLIST WAS COMPLETED. ATC WAS INFORMED THAT WE WOULD BE MAKING AN EMER LNDG IN INDIANAPOLIS AND ARFF EQUIP WAS REQUESTED. DISPATCH WAS INFORMED. THE FLT ATTENDANTS RPTED THERE WAS NO NOISE; SMOKE; VIBRATION -- JUST A SUDDEN SILENCE. I PASSED ON THE TEST INFO TO THE FLT ATTENDANTS AND TOLD THEM THAT AN EMER EVAC WAS UNLIKELY; BUT I WOULD LIKE THEM TO START THE EMER CHKLIST. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTR STATED THE EXACT CAUSE OF THE SEIZURE OF THE N2 ROTOR IS UNKNOWN AS MAINT HAS NOT RELEASED ANY FINDINGS. THE RPTR SAID WHEN THE ENG FAILED ONLY A SLIGHT YAW TO THE R WAS NOTED. THE RPTR STATED ANY ENG SEIZURE A RATHER ABRUPT AND HARD YAW WOULD BE EXPECTED; BUT THIS WAS DIFFERENT.