Cpr small aircraft had electrical problem failure at cruise altitude.

Attributes
ACN	108802
Time
Date	198904
Day	Tue
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : rvl
State Reference	PA
Altitude	msl bound lower : 0 msl bound upper : 10000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Operator	general aviation : corporate
Make Model Name	Small Aircraft, Low Wing, 1 Eng, Retractable Gear
Flight Phase	cruise other
Route In Use	enroute airway : v276
Flight Plan	IFR
Person 1
Affiliation	Other
Function	flight crew : captain oversight : pic
Qualification	pilot : commercial pilot : instrument
Experience	flight time last 90 days : 51 flight time total : 2932 flight time type : 117
ASRS Report	108802
Person 2
Affiliation	government : faa
Function	controller : radar
Qualification	controller : radar
Events
Anomaly	aircraft equipment problem : critical
Independent Detector	other controllera other flight crewa
Resolutory Action	flight crew : declared emergency none taken : unable
Consequence	Other
Supplementary
Primary Problem	Aircraft

Narrative:

ATC reported the transponder code had been lost. Autoplt failed immediately following. Lights dimmed. Turned off all electrical except one communication set. Checked alternator circuit breaker ok, alternator switch cycled, no change. Landed at reedsville airport. The alternator warning light never activated. The a&P checked the electrical system and found the battery dead with one cell low on water. Charged battery and replaced in plane. Started engine and alternator charged sixty amps. After recheck of system, continued flight to ann arbor without incident. Suspected cause: stuck voltage regulator. Future action: will activate additional electrical equipment periodically to observe the needle move. When only the radios are active, the current usage is so small that the gauge needle appears to be on zero charge.

Original NASA ASRS Text

Title: CPR SMA HAD ELECTRICAL PROBLEM FAILURE AT CRUISE ALT.

Narrative: ATC REPORTED THE XPONDER CODE HAD BEEN LOST. AUTOPLT FAILED IMMEDIATELY FOLLOWING. LIGHTS DIMMED. TURNED OFF ALL ELECTRICAL EXCEPT ONE COM SET. CHECKED ALTERNATOR CIRCUIT BREAKER OK, ALTERNATOR SWITCH CYCLED, NO CHANGE. LANDED AT REEDSVILLE ARPT. THE ALTERNATOR WARNING LIGHT NEVER ACTIVATED. THE A&P CHECKED THE ELECTRICAL SYSTEM AND FOUND THE BATTERY DEAD WITH ONE CELL LOW ON WATER. CHARGED BATTERY AND REPLACED IN PLANE. STARTED ENGINE AND ALTERNATOR CHARGED SIXTY AMPS. AFTER RECHECK OF SYSTEM, CONTINUED FLT TO ANN ARBOR WITHOUT INCIDENT. SUSPECTED CAUSE: STUCK VOLTAGE REGULATOR. FUTURE ACTION: WILL ACTIVATE ADDITIONAL ELECTRICAL EQUIPMENT PERIODICALLY TO OBSERVE THE NEEDLE MOVE. WHEN ONLY THE RADIOS ARE ACTIVE, THE CURRENT USAGE IS SO SMALL THAT THE GAUGE NEEDLE APPEARS TO BE ON ZERO CHARGE.

Data retrieved from NASA's ASRS site as of August 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.