A socata TB20 landed gear up following a total electrical failure caused by an alternator loss.

Attributes
ACN	724282
Time
Date	200701
Local Time Of Day	1801 To 2400
Place
Locale Reference	airport : zzz.airport
State Reference	US
Altitude	msl single value : 2500
Environment
Flight Conditions	VMC
Weather Elements	Turbulence
Light	Night
Aircraft 1
Controlling Facilities	tracon : zzz.tracon
Operator	general aviation : personal
Make Model Name	Trinidad TB-20
Operating Under FAR Part	Part 91
Flight Phase	descent : approach
Person 1
Affiliation	other
Function	flight crew : single pilot
Qualification	pilot : private
Experience	flight time last 90 days : 74 flight time total : 686 flight time type : 244
ASRS Report	724282
Events
Anomaly	aircraft equipment problem : critical ground encounters : gear up landing inflight encounter : turbulence other anomaly other
Independent Detector	other flight crewa
Resolutory Action	flight crew : landed in emergency condition
Consequence	faa : investigated other other
Supplementary
Problem Areas	Aircraft Environmental Factor
Primary Problem	Aircraft

Narrative:

Originating in ZZZ1 approximately XA40 hours local we experienced moderate to severe turbulence at 4500 ft and descending into ZZZ2. At this time I received an intermittent flashing of my alternator light. Landed ZZZ2 no incident; dropped off passenger and got flight follow to ZZZ3. Encountered severe turbulence 1500-4500 ft MSL -- alternator light intermittent flashes. Cleared by ATC for ILS at ZZZ3. My alternator light flashed and the cockpit went dark. Elevation +/-2500 ft MSL. I had a visual on ZZZ3 runway and dialed in 7600 on transponder -- lost communications. I idented for ATC. Inside of the bridge I lowered landing gear lever. They appeared to cycle down -- no lights in cockpit; though; and the taxi/landing lights very dim. No other visible traffic in sight. As I came in for a landing I saw sparks from the step to get on the wing and set the plane down on the runway with the gear up -- fearing that a go around at this point would be dangerous. Landed on runway 29R at ZZZ3 without major damage to the runway or the airframe. There was very slight fuel under right wing. Smell of rubber burning turned out to be a tire that scraped the ground. This incident ended with no property damage and no injuries. Minimum damage to the airframe.

Original NASA ASRS Text

Title: A SOCATA TB20 LANDED GEAR UP FOLLOWING A TOTAL ELECTRICAL FAILURE CAUSED BY AN ALTERNATOR LOSS.

Narrative: ORIGINATING IN ZZZ1 APPROX XA40 HRS LCL WE EXPERIENCED MODERATE TO SEVERE TURB AT 4500 FT AND DSNDING INTO ZZZ2. AT THIS TIME I RECEIVED AN INTERMITTENT FLASHING OF MY ALTERNATOR LIGHT. LANDED ZZZ2 NO INCIDENT; DROPPED OFF PAX AND GOT FLT FOLLOW TO ZZZ3. ENCOUNTERED SEVERE TURB 1500-4500 FT MSL -- ALTERNATOR LIGHT INTERMITTENT FLASHES. CLRED BY ATC FOR ILS AT ZZZ3. MY ALTERNATOR LIGHT FLASHED AND THE COCKPIT WENT DARK. ELEVATION +/-2500 FT MSL. I HAD A VISUAL ON ZZZ3 RWY AND DIALED IN 7600 ON XPONDER -- LOST COMS. I IDENTED FOR ATC. INSIDE OF THE BRIDGE I LOWERED LNDG GEAR LEVER. THEY APPEARED TO CYCLE DOWN -- NO LIGHTS IN COCKPIT; THOUGH; AND THE TAXI/LNDG LIGHTS VERY DIM. NO OTHER VISIBLE TFC IN SIGHT. AS I CAME IN FOR A LNDG I SAW SPARKS FROM THE STEP TO GET ON THE WING AND SET THE PLANE DOWN ON THE RWY WITH THE GEAR UP -- FEARING THAT A GAR AT THIS POINT WOULD BE DANGEROUS. LANDED ON RWY 29R AT ZZZ3 WITHOUT MAJOR DAMAGE TO THE RWY OR THE AIRFRAME. THERE WAS VERY SLIGHT FUEL UNDER R WING. SMELL OF RUBBER BURNING TURNED OUT TO BE A TIRE THAT SCRAPED THE GND. THIS INCIDENT ENDED WITH NO PROPERTY DAMAGE AND NO INJURIES. MINIMUM DAMAGE TO THE AIRFRAME.

Data retrieved from NASA's ASRS site as of January 2009 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.