Narrative:

Feb/xx/92 I and 1 passenger departed dallas love field on an IFR flight plan at xy:00 pm local time for waco regulation airport. We climbed to 6000 ft, our flight planned altitude. Upon descent in IMC conditions into waco, the tower reported they had lost our transponder. Upon crossing the OM I placed the gear handle down and heard the pump actuate. Approximately 3 mi inside the OM I noticed the lights began to pulsate weaker, then stronger, then weaker in rhythm. We broke out of the 'soup' slightly above min on a 3/4 mi final, at this time we lost all electrical power. I started a 'gump' check when I got to undercarriage, I asked my passenger who is also a pilot, to make a visual check for the gear. He opened the right window, used a flashlight and confirmed the gear was down. I proceeded with landing, and on touchdown the main gear collapsed. The nose gear remained down and locked. Damage to the airplane was minor. The right horizontal stabilizer was damaged when the airplane came to rest. Other than this there was no damage to the belly or any other mechanical structure of the airplane. It is my opinion that the master/altimeter switch had a faulty connection which allowed the battery to run the electrical system without a low voltage light illuminating.

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Original NASA ASRS Text

Title: SMA'S LNDG GEAR COLLAPSES UPON TOUCHDOWN ON RWY AFTER PRIMARY ELECTRICAL SUPPLY PROBLEM IN A NIGHT OP.

Narrative: FEB/XX/92 I AND 1 PAX DEPARTED DALLAS LOVE FIELD ON AN IFR FLT PLAN AT XY:00 PM LCL TIME FOR WACO REG ARPT. WE CLBED TO 6000 FT, OUR FLT PLANNED ALT. UPON DSCNT IN IMC CONDITIONS INTO WACO, THE TWR REPORTED THEY HAD LOST OUR TRANSPONDER. UPON XING THE OM I PLACED THE GEAR HANDLE DOWN AND HEARD THE PUMP ACTUATE. APPROX 3 MI INSIDE THE OM I NOTICED THE LIGHTS BEGAN TO PULSATE WEAKER, THEN STRONGER, THEN WEAKER IN RHYTHM. WE BROKE OUT OF THE 'SOUP' SLIGHTLY ABOVE MIN ON A 3/4 MI FINAL, AT THIS TIME WE LOST ALL ELECTRICAL PWR. I STARTED A 'GUMP' CHK WHEN I GOT TO UNDERCARRIAGE, I ASKED MY PAX WHO IS ALSO A PLT, TO MAKE A VISUAL CHK FOR THE GEAR. HE OPENED THE R WINDOW, USED A FLASHLIGHT AND CONFIRMED THE GEAR WAS DOWN. I PROCEEDED WITH LNDG, AND ON TOUCHDOWN THE MAIN GEAR COLLAPSED. THE NOSE GEAR REMAINED DOWN AND LOCKED. DAMAGE TO THE AIRPLANE WAS MINOR. THE R HORIZ STABILIZER WAS DAMAGED WHEN THE AIRPLANE CAME TO REST. OTHER THAN THIS THERE WAS NO DAMAGE TO THE BELLY OR ANY OTHER MECHANICAL STRUCTURE OF THE AIRPLANE. IT IS MY OPINION THAT THE MASTER/ALTIMETER SWITCH HAD A FAULTY CONNECTION WHICH ALLOWED THE BATTERY TO RUN THE ELECTRICAL SYS WITHOUT A LOW VOLTAGE LIGHT ILLUMINATING.

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.