Entering class C airspace at sat, tx, a C150 pilot deals with electric power failure.

Attributes
ACN	558687
Time
Date	200208
Day	Fri
Local Time Of Day	1201 To 1800
Place
Locale Reference	navaid : sat.vortac
State Reference	TX
Altitude	msl single value : 2500
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : sat.tracon
Operator	general aviation : personal
Make Model Name	Cessna 150
Operating Under FAR Part	Part 91
Flight Phase	cruise : level
Flight Plan	None
Person 1
Affiliation	other
Function	flight crew : single pilot
Qualification	pilot : instrument pilot : commercial pilot : atp pilot : multi engine
Experience	flight time last 90 days : 30 flight time total : 2800 flight time type : 60
ASRS Report	558687
Person 2
Affiliation	government : faa
Function	controller : approach
Events
Anomaly	aircraft equipment problem : critical other anomaly other
Independent Detector	other flight crewb
Resolutory Action	controller : issued new clearance controller : provided flight assist flight crew : overcame equipment problem
Consequence	other
Supplementary
Problem Areas	Aircraft
Primary Problem	Aircraft

Narrative:

While on an assigned altitude of 2500 ft MSL and while instructed to fly direct to sat, I suffered what was later determined to be a substantial loss of electrical power as a result of what I believe may have been a failure of the voltage regulator. While approaching sat, I very rapidly lost the use of my autoplt, primary communication radio, received erroneous indications on my stormscope and audio bleed-over on the aircraft audio speaker. My initial concern was control of the aircraft. Upon insuring that I had complete control of the aircraft and disengaging the autoplt, I turned due north intending to depart class C airspace as I had no clearance to land. Once either clear of class C airspace or on the verge thereof, I re-established radio contact with sat approach control and confirmed my new discrete transponder code (I had currently switched to 7600 to indicate loss of 2-WAY radio communications). I then received a subsequent landing clearance. In addition, the assistance I received from sat approach control was very helpful, understanding of my predicament and, above all, extraordinarily reassuring. The remainder of the flight was conducted safely and without incident.

Original NASA ASRS Text

Title: ENTERING CLASS C AIRSPACE AT SAT, TX, A C150 PLT DEALS WITH ELECTRIC PWR FAILURE.

Narrative: WHILE ON AN ASSIGNED ALT OF 2500 FT MSL AND WHILE INSTRUCTED TO FLY DIRECT TO SAT, I SUFFERED WHAT WAS LATER DETERMINED TO BE A SUBSTANTIAL LOSS OF ELECTRICAL PWR AS A RESULT OF WHAT I BELIEVE MAY HAVE BEEN A FAILURE OF THE VOLTAGE REGULATOR. WHILE APCHING SAT, I VERY RAPIDLY LOST THE USE OF MY AUTOPLT, PRIMARY COM RADIO, RECEIVED ERRONEOUS INDICATIONS ON MY STORMSCOPE AND AUDIO BLEED-OVER ON THE ACFT AUDIO SPEAKER. MY INITIAL CONCERN WAS CTL OF THE ACFT. UPON INSURING THAT I HAD COMPLETE CTL OF THE ACFT AND DISENGAGING THE AUTOPLT, I TURNED DUE N INTENDING TO DEPART CLASS C AIRSPACE AS I HAD NO CLRNC TO LAND. ONCE EITHER CLR OF CLASS C AIRSPACE OR ON THE VERGE THEREOF, I RE-ESTABLISHED RADIO CONTACT WITH SAT APCH CTL AND CONFIRMED MY NEW DISCRETE XPONDER CODE (I HAD CURRENTLY SWITCHED TO 7600 TO INDICATE LOSS OF 2-WAY RADIO COMS). I THEN RECEIVED A SUBSEQUENT LNDG CLRNC. IN ADDITION, THE ASSISTANCE I RECEIVED FROM SAT APCH CTL WAS VERY HELPFUL, UNDERSTANDING OF MY PREDICAMENT AND, ABOVE ALL, EXTRAORDINARILY REASSURING. THE REMAINDER OF THE FLT WAS CONDUCTED SAFELY AND WITHOUT 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.