Small aircraft in IMC has electrical failure.

Attributes
ACN	265577
Time
Date	199403
Day	Tue
Local Time Of Day	0601 To 1200
Place
Locale Reference	airport : lvk
State Reference	CA
Altitude	msl bound lower : 4000 msl bound upper : 4000
Environment
Flight Conditions	IMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : oak
Operator	general aviation : instructional
Make Model Name	Cessna 210 Centurion / Turbo Centurion 210C, 210D
Operating Under FAR Part	Part 91
Flight Phase	cruise other
Route In Use	enroute : on vectors
Flight Plan	IFR
Person 1
Affiliation	Other
Function	flight crew : single pilot
Qualification	pilot : instrument pilot : commercial pilot : cfi
Experience	flight time last 90 days : 160 flight time total : 1450 flight time type : 40
ASRS Report	265577
Person 2
Affiliation	government : faa
Function	controller : approach
Qualification	controller : radar
Events
Anomaly	aircraft equipment problem : critical other anomaly other
Independent Detector	aircraft equipment other aircraft equipment : unspecified other other : unspecified cockpit
Resolutory Action	flight crew : declared emergency other
Consequence	Other
Supplementary
Primary Problem	Aircraft

Narrative:

While en route from apc to sjc on an IFR flight I noticed the low voltage warning light illuminate. However, the ammeter showed no discharge. I recycled the main master switch and the voltage light went out. I continued to watch the ammeter carefully. Around oakland I received the instruction 'fly heading 120 degrees radar vectors ILS runway 30L.' when I was told to contact bay approach on 135.40 I changed frequency but could not make contact with the next controller. My communication radios were not working, then my navigation radios quit, and then the LORAN. At this point I realized that I had an electrical failure. The ammeter still showed no discharge. I was IMC so I squawked 7600 and in a matter of mins broke out into VFR conditions. I had continued to maintain 4000 ft and heading 120 degrees, the last instructions received. Knowing I should be near livermore, I began to look for it. I found livermore airport and circled down while I pumped down my landing gear manually and looked for pattern traffic and wind conditions. Because of a fog bank on the north side of the runways I made a left traffic for runway 25R, received the light gun signals, and landed. After landing I immediately phoned bay TRACON and livermore tower who both said that my situation had caused no problems and they were glad that I was down and safe. Later when our mechanics fixed the 210 they said that the problem had been a failure in-flight of the voltage regulator (acu) and associated wiring. I was the sole occupant during this incident.

Original NASA ASRS Text

Title: SMA IN IMC HAS ELECTRICAL FAILURE.

Narrative: WHILE ENRTE FROM APC TO SJC ON AN IFR FLT I NOTICED THE LOW VOLTAGE WARNING LIGHT ILLUMINATE. HOWEVER, THE AMMETER SHOWED NO DISCHARGE. I RECYCLED THE MAIN MASTER SWITCH AND THE VOLTAGE LIGHT WENT OUT. I CONTINUED TO WATCH THE AMMETER CAREFULLY. AROUND OAKLAND I RECEIVED THE INSTRUCTION 'FLY HDG 120 DEGS RADAR VECTORS ILS RWY 30L.' WHEN I WAS TOLD TO CONTACT BAY APCH ON 135.40 I CHANGED FREQ BUT COULD NOT MAKE CONTACT WITH THE NEXT CTLR. MY COM RADIOS WERE NOT WORKING, THEN MY NAV RADIOS QUIT, AND THEN THE LORAN. AT THIS POINT I REALIZED THAT I HAD AN ELECTRICAL FAILURE. THE AMMETER STILL SHOWED NO DISCHARGE. I WAS IMC SO I SQUAWKED 7600 AND IN A MATTER OF MINS BROKE OUT INTO VFR CONDITIONS. I HAD CONTINUED TO MAINTAIN 4000 FT AND HDG 120 DEGS, THE LAST INSTRUCTIONS RECEIVED. KNOWING I SHOULD BE NEAR LIVERMORE, I BEGAN TO LOOK FOR IT. I FOUND LIVERMORE ARPT AND CIRCLED DOWN WHILE I PUMPED DOWN MY LNDG GEAR MANUALLY AND LOOKED FOR PATTERN TFC AND WIND CONDITIONS. BECAUSE OF A FOG BANK ON THE N SIDE OF THE RWYS I MADE A L TFC FOR RWY 25R, RECEIVED THE LIGHT GUN SIGNALS, AND LANDED. AFTER LNDG I IMMEDIATELY PHONED BAY TRACON AND LIVERMORE TWR WHO BOTH SAID THAT MY SIT HAD CAUSED NO PROBS AND THEY WERE GLAD THAT I WAS DOWN AND SAFE. LATER WHEN OUR MECHS FIXED THE 210 THEY SAID THAT THE PROB HAD BEEN A FAILURE INFLT OF THE VOLTAGE REGULATOR (ACU) AND ASSOCIATED WIRING. I WAS THE SOLE OCCUPANT DURING THIS INCIDENT.

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.