What was found
(CAN) RT ENGINE CHIP DETECTOR INDICATION ILLUMINATED IN FLIGHT. ACFT RETURNED TO BASE AND LANDED UNEVENTFULLY. THE CREW RETARDED NR 2 ENGINE TO GROUND IDLE, BUT DID NOT SHUTDOWN THE ENGINE. OEI OPERATION WAS APPROXIMATELY 25 MINUTES. CHIP DETECTOR REMOVED & CHECKED. HAIR LIKE STRAND FOUND BRIDGED POLES. OIL FILTER REMOVED, NO DEBRIS FOUND IN FILTER OR IN BOWL. DCU DOWNLOADED TO DETERMINE OEI USAGE FOR NR 1 ENGINE. ALL OPERATION WAS WITHIN NORMAL ENGINE LIMITS WITH NO INCURSIONS INTO OEI LIMITS. BASED ON PRECEDING, THE ACFT RETURNED TO SERVICE.