Narrative:

Had called ZOA approximately 50 mi from sns and requested ILS 31 into sns. At time, under VFR flight following on trip from smo to sns, center asked if a would like to go IFR or make the approach in VFR. I stated that it 'didn't matter' and I was given an IFR clearance and told to descend from 8500 ft to 8000 ft. A few mins later, I was told to report to monterey approach on frequency 133.0. Mry gave me a vector to intercept the localizer and descend to 5500 ft. I reported established and reduced power and set up to fly down the ILS. At the time it was nearly sunset. Monterey reported traffic at 3000 ft and 12 O'clock. At that time, I was at +/-4000 ft and approximately 14 mi out (DME). In less than 1 second, all the aircraft electrical system failed. I tried the circuit breakers after turning off the radios and resetting the transponder to 7600. Nothing worked to establish electrical. The only guidance was a handheld GPS running on its batteries. In view of ILS clearance, I continued approach. At approximately 1 1/2 mi from airport, I could see 3 other aircraft on far side of airport. I did a tight holding pattern at 700 ft just southeast of control tower. I made 2 complete circuits before receiving a green light. The landing and taxi were uneventful. A later conversation with the tower personnel revealed that 1) they had been informed by mry to expect a NORDO on the ILS, and 2) they couldn't see me until I made the second turn around the impromptu holding pattern. My suggestion is that one person in tower be assigned to look for the NORDO (I was front-lit by the setting sun), so that extra mins won't have been wasted waiting for a green light.

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Original NASA ASRS Text

Title: A C175, INBOUND ON THE RWY 31 ILS TO SNS, LOSES ALL ELECTRICAL PWR AND IS CLRED TO LAND VIA THE TWR SIGNAL LIGHT CTL.

Narrative: HAD CALLED ZOA APPROX 50 MI FROM SNS AND REQUESTED ILS 31 INTO SNS. AT TIME, UNDER VFR FLT FOLLOWING ON TRIP FROM SMO TO SNS, CTR ASKED IF A WOULD LIKE TO GO IFR OR MAKE THE APCH IN VFR. I STATED THAT IT 'DIDN'T MATTER' AND I WAS GIVEN AN IFR CLRNC AND TOLD TO DSND FROM 8500 FT TO 8000 FT. A FEW MINS LATER, I WAS TOLD TO RPT TO MONTEREY APCH ON FREQ 133.0. MRY GAVE ME A VECTOR TO INTERCEPT THE LOC AND DSND TO 5500 FT. I RPTED ESTABLISHED AND REDUCED PWR AND SET UP TO FLY DOWN THE ILS. AT THE TIME IT WAS NEARLY SUNSET. MONTEREY RPTED TFC AT 3000 FT AND 12 O'CLOCK. AT THAT TIME, I WAS AT +/-4000 FT AND APPROX 14 MI OUT (DME). IN LESS THAN 1 SECOND, ALL THE ACFT ELECTRICAL SYS FAILED. I TRIED THE CIRCUIT BREAKERS AFTER TURNING OFF THE RADIOS AND RESETTING THE XPONDER TO 7600. NOTHING WORKED TO ESTABLISH ELECTRICAL. THE ONLY GUIDANCE WAS A HANDHELD GPS RUNNING ON ITS BATTERIES. IN VIEW OF ILS CLRNC, I CONTINUED APCH. AT APPROX 1 1/2 MI FROM ARPT, I COULD SEE 3 OTHER ACFT ON FAR SIDE OF ARPT. I DID A TIGHT HOLDING PATTERN AT 700 FT JUST SE OF CTL TWR. I MADE 2 COMPLETE CIRCUITS BEFORE RECEIVING A GREEN LIGHT. THE LNDG AND TAXI WERE UNEVENTFUL. A LATER CONVERSATION WITH THE TWR PERSONNEL REVEALED THAT 1) THEY HAD BEEN INFORMED BY MRY TO EXPECT A NORDO ON THE ILS, AND 2) THEY COULDN'T SEE ME UNTIL I MADE THE SECOND TURN AROUND THE IMPROMPTU HOLDING PATTERN. MY SUGGESTION IS THAT ONE PERSON IN TWR BE ASSIGNED TO LOOK FOR THE NORDO (I WAS FRONT-LIT BY THE SETTING SUN), SO THAT EXTRA MINS WON'T HAVE BEEN WASTED WAITING FOR A GREEN LIGHT.

Data retrieved from NASA's ASRS site as of July 2007 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.