What was found
(CAN) DURING THE PREVIOUS FLIGHT THE ALTERNATOR LIGHT ILLUMINATED 3 TIMES AND WAS SUCCESSFULLY RESET EACH TIME. UPON THE 4TH OCCURRENCE THE HELICOPTER RETURN TO THE HANGAR. THE ALTERNATOR CONTROL UNIT AND THE ALTERNATOR SWITCH WERE REPLACED. A SUCCESSFUL GROUND RUN AND 20 MINUTE TEST FLIGHT WERE CARRIED OUT. DURING THE NEXT FLIGHT THE ALTERNATOR LIGHT ILLUMINATED AGAIN. THE HELICOPTER RETURNED TO THE HANGAR AND THE ALTERNATOR WAS REPLACED WITH A NEW ONE, ONCE AGAIN (3.8 HOURS SINCE A NEW ONE WAS INSTALLED). A SUCCESSFUL GROUND RUN AND 20 MINUTE TEST FLIGHT WERE CARRIED OUT. (TC# 20190422020)