RWY EXCURSION AFTER SMT'S LONG GEAR COLLAPSES DURING A TOUCH AND GO. ACFT DAMAGED.

Narrative

I WAS CHKING OUT AN SMT TWIN TURBO AFTER 8-9 MONTHS OF MAINT AND UNUSE. WHILE IN THE PATTERN AT PIE; I WAS PERFORMING TOUCH-AND-GOES AND CHKING OUT THE SYS AND AVIONICS TO SEE IF ANY EQUIP NEEDED REPAIR AFTER SUCH A LONG PERIOD OF UNUSE. THE PLANE HAD JUST BEEN THROUGH A PERIODIC INSPECTION AS WELL AS A 5 YR GEAR OVERHAUL. I HAD FLOWN THE PLANE FROM SARASOTA TO ST PETERSBURG 2 DAYS EARLIER AND NOTICED AN OCCASIONAL GEAR UNSAFE LIGHT ON THE L MAIN GEAR. I BROUGHT THE PLANE OVER TO THE MAINT FACILITY THAT HAD WORKED ON THE GEAR AND THEY MADE A MINOR ADJUSTMENT TO THE DOWN MICROSWITCH. THIS APPEARED TO FIX THE PROBLEM. DURING THE PREFLT INSPECTION; EVERYTHING LOOKED NORMAL IN THE GEAR WELL AND THE STRUT LOOKED 'OVER CTR.' AFTER MY SECOND LNDG IN THE PATTERN; THE PLANE ROLLED ABOUT 500 FT AFTER TOUCHDOWN WHILE I RESET THE TRIM AND FLAPS FOR THE TOUCH-AND-GO. SUDDENLY; THE L GEAR COLLAPSED BACK TOWARD RETRACTION. I SHUT DOWN BOTH ENGS WITH EMER CUTOFF AND FEATHER WHILE MAINTAINING DIRECTIONAL CTL WITH THE R BRAKE. THE PLANE SLID ABOUT 850 FT AND STOPPED JUST TO THE L OF THE RWY IN THE GRASS AT MIDFIELD. THE DAMAGE TO THE PLANE WAS LIMITED TO THE SCRAPED BELLY SKIN AND THE L PROP THAT HAD STRUCK THE GND IN FEATHER. INITIAL INSPECTION SHOWED THAT THE FITTING TO WHICH THE HYD ACTUATOR CONNECTS TO THE STRUT HAD SHEARED ALLOWING THE L GEAR TO FOLD BACK. THERE WERE NO INJURIES. MYSELF AND MY PAX EXITED THE PLANE QUICKLY. MAINT JACKED UP THE WING; PULLED THE GEAR BACK INTO PLACE AND TOWED IT TO THE HANGAR. IN RETROSPECT; PERHAPS THE FAULTY GEAR WARNING LIGHT WAS AN INDICATION THAT MORE WAS WRONG WITH THE GEAR THAN JUST A MICROSWITCH OUT OF ADJUSTMENT.