As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING SERVICE CHECK, FOUND NR 4 ENGINE C1 COMPRESSOR BLADE HAD RUBBED A .75 BY 2.25 INCH HOLE; HOUSING BETWEEN C1 AND C2 HAD A .25 BY 3 INCH GAP, BOTH AT THE 4 O'CLOCK POSITION. THREE ENGINE FERRIED AIRCRAFT BACK TO ILN. REPLACED NR 4 ENGINE IAW JOB CARD J7002.