As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
WHILE ACCOMPLISHING T/C SBCFM56-7B-72-0986-1, FOUND THE 9 O'CLOCK ANTI-ROTATION PIN AT THE THIRD STAGE SEGMENT SEAT HAD ROTATED, GREATER THAN 45 DEGREES AND LESS THAN 90 DEGREES, THE PIN HAD ALSO MIGRATED. ACFT GROUNDED. REMOVED AND REPLACED THE NR 1 ENGINE IAW WO 387607.