A BE33 PLT DECLARED AN EMER; THEREBY DECLINING A GAR DIRECTION BY ZOA WHILE ON THE ILS RWY 13L TO CIC.

Narrative

35 MINS INTO FLT; 'ALTERNATOR FAIL' LIGHT ILLUMINATED. PLACED BACK ON BUSS SUCCESSFULLY BY CYCLING THE BATTERY SWITCH (THIS SIT HAD OCCURRED FREQUENTLY DURING THE OCTOBER-NOVEMBER TIME FRAME; BUT HAD BEEN SUCCESSFULLY REPAIRED BY RECONDITIONED ALTERNATOR AND NEW BATTERY SWITCHES; ETC). NO PROB FOR AT LEAST 6 WKS. PREVIOUSLY; 30 MINS INTO FLT; HAD CHANGED FROM L-HAND TO R-HAND FUEL TANK. 1 HR 5 MINS INTO FLT; ARRIVED ABEAM CIC. IMC; FROM BAKERSFIELD N IN THE VALLEY; ALL THE WAY TO REDDING FORECAST HAD BEEN 3000 FT SCATTERED FOR CIC. 1 HR 15 MINS INTO FLT; 'ALTERNATOR FAIL' LIGHT CAME ON. BATTERY SWITCH CYCLE SUCCESSFUL. (UNDER VECTORS BY ZOA TO INTERCEPT LOC ILS RWY 13L.) 1 HR 25 MINS INTO FLT; INITIATED MISSED APCH PROCS (HAD USED AUTOPLT NAV COUPLING PROCS WHILE INTERCEPTING LOC). IT SEEMED TO OVERREACT DURING THE 'CAPTURE' PHASE WITH EXCESSIVE TURN TO CTR THE LOC; THEN STRONG DSCNT ACTION TO CTR GLIDE PATH. I TOOK OVER MANUALLY BUT WAS RELUCTANT TO CONTINUE DSCNT WITH NEEDLES WELL OFF CTR. I HAD UTILIZED THE SYS TO LAND EARLIER SAME DAY AT CNO IN HAZY; NOT IMC CONDITIONS. 1 HR 35 MINS INTO FLT; 'ALTERNATOR FAIL' LIGHT CAME ON. BATTERY SWITCH CYCLE SUCCESSFUL. (UNDER VECTORS BY ZOA; NOW VECTOR GUIDANCE WENT OUTBOUND MORE THAN 20 MI DUE TO INTERCEPT SPACING (4TH IN PATTERN FOR ILS TO CIC). STILL IMC; I INTERCEPTED LOC WHILE FLYING MANUALLY. PLACED THE GEAR DOWN TO START DSCNT ON CTRED GS NEEDLE. SOON BECAME APPARENT THAT THE GS INDICATOR WAS NOT MOVING; BUT FROZEN IN THE CTR POS. ELECTED TO FOLLOW LOC; ONLY TO CIRCLING MINIMUMS (640 FT MSL). REACTION TO FOLLOWING THIS DECISION RESULTED IN BREAKING OUT OF OVCST AT APPROX 750 FT MSL; BUT ALREADY OVER RWY THRESHOLD. CIC TWR CALLED TO SAY ZOA DIRECTED ME TO PERFORM PUBLISHED MISSED APCH PROC. 1 HR 52 MINS INTO FLT; ADVISED CIC TWR THAT I INTENDED TO MAINTAIN CIRCLING MINIMUMS; FLY A MODIFIED VISUAL PATTERN AND LAND ON THAT SAME ILS RWY (RWY 13L). TWR ASKED IF I WAS DECLARING AN EMER. I ANSWERED IN THE AFFIRMATIVE. FACTORS BEARING ON THIS DECISION INCLUDED: 1) UNCERTAINTY ABOUT ALTERNATOR PWR SIT. NOW DARK WITH LOW CEILINGS. 2) CONCERN ABOUT EXTENDED MISSED APCH PROCS TAKING UP TO 30 MINS. THIS WOULD REQUIRE SWITCHING FUEL BACK TO L-HAND TANK (UNCERTAIN ABOUT FUEL REMAINING; BASED UPON TIME OF USAGE ONLY -- FUEL GAUGES WORTHLESS). 3) ASSURANCE THAT I HAD THE DEST RWY IN VISUAL CONDITIONS AND COULD LAND SAFELY; THUS ELIMINATING ALL THE PROBS ABOVE.