An small aircraft instructor reports an electrical failure at night on an IFR flight plan.

Attributes
ACN	258361
Time
Date	199311
Day	Sun
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : mem airport : vcy
State Reference	TN
Altitude	msl bound lower : 5000 msl bound upper : 5000
Environment
Flight Conditions	VMC
Light	Night
Aircraft 1
Operator	general aviation : personal
Make Model Name	Small Aircraft, Low Wing, 1 Eng, Fixed Gear
Flight Phase	cruise other
Route In Use	enroute airway : zme
Flight Plan	IFR
Person 1
Affiliation	Other
Function	instruction : instructor
Qualification	pilot : cfi
Experience	flight time last 90 days : 45 flight time total : 660 flight time type : 50
ASRS Report	258361
Person 2
Affiliation	Other
Function	instruction : trainee
Events
Anomaly	aircraft equipment problem : less severe other anomaly other
Independent Detector	other flight crewa
Resolutory Action	none taken : unable
Consequence	Other
Supplementary
Primary Problem	Aircraft
Air Traffic Incident	other

Narrative:

We were on an IFR flight plan south of the mem class B airspace in an small aircraft. Our first indication of trouble came when ZME told su they were no longer receiving our transponder. Upon checking the ammeter, we noticed it was not 'pulling a load.' in anticipation of a radio failure, we chose to cancel our IFR and continue the flight in VMC conditions. However, we were unable to inform ZME of our intention before complete radio failure. The last transmission we heard was another aircraft informing center they heard us say we were canceling IFR. We continued the flight under VFR and deviated around the mem class B. Without a landing light we decided it would be most practicable to land at our home base, ucy. Sits such as this could be avoided if aircraft were equipped with instrumentation that warns of imminent alternator failure, not just tells a pilot after the fact. Another option could be placing a redundant electric system on aircraft flown under IFR.

Original NASA ASRS Text

Title: AN SMA INSTRUCTOR RPTS AN ELECTRICAL FAILURE AT NIGHT ON AN IFR FLT PLAN.

Narrative: WE WERE ON AN IFR FLT PLAN S OF THE MEM CLASS B AIRSPACE IN AN SMA. OUR FIRST INDICATION OF TROUBLE CAME WHEN ZME TOLD SU THEY WERE NO LONGER RECEIVING OUR XPONDER. UPON CHKING THE AMMETER, WE NOTICED IT WAS NOT 'PULLING A LOAD.' IN ANTICIPATION OF A RADIO FAILURE, WE CHOSE TO CANCEL OUR IFR AND CONTINUE THE FLT IN VMC CONDITIONS. HOWEVER, WE WERE UNABLE TO INFORM ZME OF OUR INTENTION BEFORE COMPLETE RADIO FAILURE. THE LAST XMISSION WE HEARD WAS ANOTHER ACFT INFORMING CTR THEY HEARD US SAY WE WERE CANCELING IFR. WE CONTINUED THE FLT UNDER VFR AND DEVIATED AROUND THE MEM CLASS B. WITHOUT A LNDG LIGHT WE DECIDED IT WOULD BE MOST PRACTICABLE TO LAND AT OUR HOME BASE, UCY. SITS SUCH AS THIS COULD BE AVOIDED IF ACFT WERE EQUIPPED WITH INSTRUMENTATION THAT WARNS OF IMMINENT ALTERNATOR FAILURE, NOT JUST TELLS A PLT AFTER THE FACT. ANOTHER OPTION COULD BE PLACING A REDUNDANT ELECTRIC SYS ON ACFT FLOWN UNDER IFR.

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.