Electrical system failure due to alternator, voltage regulator failure.

Attributes
ACN	268246
Time
Date	199404
Day	Sun
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : cmk airport : hpn
State Reference	NY
Altitude	msl bound lower : 7000 msl bound upper : 7000
Environment
Flight Conditions	IMC
Light	Daylight
Aircraft 1
Controlling Facilities	tower : lga
Operator	general aviation : personal
Make Model Name	Any Unknown or Unlisted Aircraft Manufacturer
Operating Under FAR Part	Part 91
Flight Phase	cruise other other
Route In Use	enroute airway : n90
Flight Plan	IFR
Person 1
Affiliation	Other
Function	flight crew : single pilot
Qualification	pilot : commercial pilot : instrument
Experience	flight time last 90 days : 11 flight time total : 950 flight time type : 100
ASRS Report	268246
Person 2
Affiliation	government : faa
Function	controller : approach
Qualification	controller : radar
Events
Anomaly	aircraft equipment problem : critical
Independent Detector	aircraft equipment other aircraft equipment : unspecified other flight crewa
Resolutory Action	flight crew : declared emergency none taken : unable other
Consequence	Other
Supplementary
Primary Problem	Aircraft

Narrative:

Flight on previous day (orh to teb) was VFR and uneventful. Return to orh was IFR. Run-up and climb were normal. After leveling at 7000 ft AGL, radios faded. A check of system revealed `altitude' circuit breaker had tripped. It was reset, radio contact was reestablished and controller reported radar transponder was not being received. Transponder was reset and worked. A short time later, circuit breaker tripped again and was reset. At this point, burning insulation was smelled in the cockpit by both pilot and passenger. The `altitude' circuit breaker was opened and landing at the nearest airport was requested. Pilot used own navigation and made ILS 16 approach at hpn without incident. The aircraft was taxied to a service facility. Alternator windings had fused and rotor was worn where brushes made contact. The alternator and voltage regulator were replaced, as was the master switch. However, a positive reading on the ammeter is still not present and maintenance is continuing to trouble- shoot the problem.

Original NASA ASRS Text

Title: ELECTRICAL SYS FAILURE DUE TO ALTERNATOR, VOLTAGE REGULATOR FAILURE.

Narrative: FLT ON PREVIOUS DAY (ORH TO TEB) WAS VFR AND UNEVENTFUL. RETURN TO ORH WAS IFR. RUN-UP AND CLB WERE NORMAL. AFTER LEVELING AT 7000 FT AGL, RADIOS FADED. A CHK OF SYS REVEALED `ALT' CIRCUIT BREAKER HAD TRIPPED. IT WAS RESET, RADIO CONTACT WAS REESTABLISHED AND CTLR RPTED RADAR XPONDER WAS NOT BEING RECEIVED. XPONDER WAS RESET AND WORKED. A SHORT TIME LATER, CIRCUIT BREAKER TRIPPED AGAIN AND WAS RESET. AT THIS POINT, BURNING INSULATION WAS SMELLED IN THE COCKPIT BY BOTH PLT AND PAX. THE `ALT' CIRCUIT BREAKER WAS OPENED AND LNDG AT THE NEAREST ARPT WAS REQUESTED. PLT USED OWN NAV AND MADE ILS 16 APCH AT HPN WITHOUT INCIDENT. THE ACFT WAS TAXIED TO A SVC FACILITY. ALTERNATOR WINDINGS HAD FUSED AND ROTOR WAS WORN WHERE BRUSHES MADE CONTACT. THE ALTERNATOR AND VOLTAGE REGULATOR WERE REPLACED, AS WAS THE MASTER SWITCH. HOWEVER, A POSITIVE READING ON THE AMMETER IS STILL NOT PRESENT AND MAINT IS CONTINUING TO TROUBLE- SHOOT THE PROB.

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.