As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
SFO - NOISE AND VIBRATION REPORTED FROM RT ENGINE WITH POWER LEVER IN GROUND IDLE. MAINTENANCE REMOVED AND REPLACED RT ENGINE ASSY. AIRCRAFT RETURNED TO SERVICE. SUBSEQUENT INVESTIGATION REVEALED PT-1 DISK BLADE FAILURE TO BE CAUSE OF ENGINE NOISE AND VIBRATION. (X)