C-310 experiences a primary electrical supply problem, in stages.

Attributes
ACN	272167
Time
Date	199405
Day	Sun
Local Time Of Day	0601 To 1200
Place
Locale Reference	airport : smx
State Reference	CA
Altitude	msl bound lower : 2000 msl bound upper : 2000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tower : smx
Operator	general aviation : corporate
Make Model Name	Cessna 310/T310C
Operating Under FAR Part	Part 91
Flight Phase	climbout : intermediate altitude
Flight Plan	IFR
Person 1
Affiliation	Other
Function	flight crew : single pilot
Qualification	pilot : instrument pilot : cfi pilot : commercial
Experience	flight time last 90 days : 35 flight time total : 4000 flight time type : 1100
ASRS Report	272167
Person 2
Affiliation	government : faa
Function	controller : local
Qualification	controller : non radar
Events
Anomaly	aircraft equipment problem : critical non adherence : far non adherence other
Independent Detector	other flight crewa
Resolutory Action	none taken : anomaly accepted
Consequence	Other
Supplementary
Primary Problem	Aircraft
Air Traffic Incident	Pilot Deviation

Narrative:

Departed smx approximately AM00 local. Mission was a business trip smx direct sql direct rno direct sql direct smx. On climb out from smx, noted right alternator had failed. Left alternator working fine. Upon landing at sql to pick up my passenger, inspected right alternator and satisfied myself that the problem was nonmechanical and the aircraft was safe to fly. Also phoned a&P, described symptoms, and mechanic concurred. I continued the mission. No further problems during sql direct rno and rno direct sql legs. However, during sql direct smx final leg, erratic loadmeter indications. Upon arriving in traffic pattern at smx, lowered landing gear, flaps, and turned on landing lights. Loadmeter indicated less than 50 amp load on 100-amp alternator. While turning base leg, left alternator failed. Landed on battery power only. Both alternators required replacement. I subsequently discovered that 2 alternators are listed in the cessna T310R 'required equipment list.' consequently, it was probably a violation of far 91.213(D)(ii) for me to have continued beyond sql with 1 alternator. In hindsight, I should have returned to smx as soon as the first alternator-out indication was observed.

Original NASA ASRS Text

Title: C-310 EXPERIENCES A PRIMARY ELECTRICAL SUPPLY PROB, IN STAGES.

Narrative: DEPARTED SMX APPROX AM00 LCL. MISSION WAS A BUSINESS TRIP SMX DIRECT SQL DIRECT RNO DIRECT SQL DIRECT SMX. ON CLBOUT FROM SMX, NOTED R ALTERNATOR HAD FAILED. L ALTERNATOR WORKING FINE. UPON LNDG AT SQL TO PICK UP MY PAX, INSPECTED R ALTERNATOR AND SATISFIED MYSELF THAT THE PROB WAS NONMECHANICAL AND THE ACFT WAS SAFE TO FLY. ALSO PHONED A&P, DESCRIBED SYMPTOMS, AND MECHANIC CONCURRED. I CONTINUED THE MISSION. NO FURTHER PROBS DURING SQL DIRECT RNO AND RNO DIRECT SQL LEGS. HOWEVER, DURING SQL DIRECT SMX FINAL LEG, ERRATIC LOADMETER INDICATIONS. UPON ARRIVING IN TFC PATTERN AT SMX, LOWERED LNDG GEAR, FLAPS, AND TURNED ON LNDG LIGHTS. LOADMETER INDICATED LESS THAN 50 AMP LOAD ON 100-AMP ALTERNATOR. WHILE TURNING BASE LEG, L ALTERNATOR FAILED. LANDED ON BATTERY PWR ONLY. BOTH ALTERNATORS REQUIRED REPLACEMENT. I SUBSEQUENTLY DISCOVERED THAT 2 ALTERNATORS ARE LISTED IN THE CESSNA T310R 'REQUIRED EQUIP LIST.' CONSEQUENTLY, IT WAS PROBABLY A VIOLATION OF FAR 91.213(D)(II) FOR ME TO HAVE CONTINUED BEYOND SQL WITH 1 ALTERNATOR. IN HINDSIGHT, I SHOULD HAVE RETURNED TO SMX AS SOON AS THE FIRST ALTERNATOR-OUT INDICATION WAS OBSERVED.

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.