As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
WHILE ON APPROACH FOR A SLING LOAD PICK THE AIRCRAFT EXPERIENCED A DUAL ALTERNATOR FAILURE. THE NR 2 TRANSFORMER RECTIFIER UNIT WAS INDICATING IT REMAINED ONLINE. THE NR 1 ALTERNATOR DISPLAYED 116 VAC ON ALL PHASES. "ELEC" AND "NAV" LIGHTS ON THE 7 ALPHA PANEL ILLUMINATED. ALL EQUIPMENT ON THE AC BUS BARS AND THE SECONDARY DC BUSES WERE OFF LINE.