ALT EXCURSION ON AN ILS APCH BY AN AC690B SINGLE PLT WHEN THE AUTOPLT ELECTRICAL PWR WAS BEING INTERRUPTED FOR THE SECOND TIME ON APCH TO CRG; FL.

Narrative

ENRTE FROM ALMA VOR (AMG) TO CRAIG FIELD IN JACKSONVILLE; FL; THE AC690B TURBO COMMANDER I WAS FLYING HAD AN ELECTRICAL FAILURE. THE FAILURE WAS ON THE CTL BUS CIRCUITRY. I PUSHED THE TIE BREAKER (SUB-PANEL) IN. THIS TIE HELD FOR 5 MINS; THEN POPPED. I RESET THE SUB-PANEL TIE BREAKER AND ALSO SET THE CTL TIE BREAKER SWITCH OVERHEAD. THIS HELD WITH ONLY POPPING TWICE. ONCE ON DSCNT INTO JACKSONVILLE; THE SECOND TIME WHILE SHOOTING THE ILS RWY 32 APCH INTO CRAIG. I HAD INTERCEPTED THE LOC INBOUND (AFTER RADAR VECTORING) AT 1900 FT MSL. I WAS DSNDED DOWN TO 1400 FT AGL AND WAS DIRECTED TO TRACK THE LOC INBOUND AND CONTACT CRAIG TWR. I WAS FLYING ON AUTOPLT WHEN THE CTL CIRCUIT TRIPPED; TURNING OFF THE AUTOPLT. AS I LEANED OVER TO RESET BREAKERS; THE ACFT DSNDED DOWN FROM 1400 FT AGL TO 900 FT AGL; SETTING OFF AN ALT ALERT IN THE TWR. I ADVISED TWR OF AUTOPLT FAILURE AS I WAS CLBING TO INTERCEPT THE GS. WE LANDED WITHOUT INCIDENT. WE WERE IN VFR CONDITIONS AT 1400 FT AGL WITH 10 MI VISIBILITY. HINDSIGHT: SHOULD HAVE HAND FLOWN TO LAND AND RESET THE CTL CIRCUIT AFTER CLRING RWY IN ORDER TO SHUT DOWN.