As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
APU SHUTDOWN WHILE RUNNING. LOW OIL PRESSURE LIGHT ILLUMINATED. F/A REPORTED A GRINDING SOUND IN REAR OF ACFT. ACFT GROUNDED. INSPECTED TAIL PIPE NO DAMAGE NOTED. INSPECTED INLET GUIDE VANES AND BLADES OF LOAD COMPRESSOR IMPELLER NO DAMAGE NOTED REF MM 49-21-00-200-801H(3). CHECKED CHIP DETECTOR FOR METAL, NO METAL NOTED OIL TANK FULL. REPLACED LOW OIL PRESSURE SWITCH REF MM 49-94-22 F 1H AND FIM 49-90-00. ACCOMPLISHED OPS CHECK AND CHECKED CDU FOR FAULTS, NO FAULTS NOTED. NO GRINDING SOUNDS NOTED.