ACR LGT MAIN LNDG GEAR COLLAPSED AT GATE WHEN ACFT BEING FUELED FOR NEXT FLT.

Narrative

ACFT WAS PREFLTED IN ACCORDANCE WITH COMPANY PROCS AND DEPARTED FORT LAUDERDALE. FLT WAS ROUTINE TO ATL; GA. ACFT WAS PARKED AT CONCOURSE GATE. WE DEPARTED MLG TO CONNECT WITH OUR NEXT FLT TO DTW. AFTER A R.O.N. IN DTW THE CAPT HAD A MESSAGE TO CALL (SIC) AT TELEPHONE NO XXXX. THE CAPT WAS INFORMED THAT ONE OF THE MAIN GEARS HAD COLLAPSED ON LGT WHILE PARKED AT THE GATE. AS FLT ENGINEER ON FLT; I WOULD LIKE TO STATE THAT NO DISCREPANCIES WERE DISCOVERED ON PREFLT IN FLL; AND THE FLT TO ATL WAS ROUTINE. THE ACFT WAS OPERATED COMPLETELY IN COMPLIANCE WITH COMPANY PROCS; MANUALS; AND CHKLIST. THE LNDG IN ATL WAS TEXT BOOK WITH A SMOOTH T/D. AT NO TIME WHILE I WAS ON LGT WAS THERE ANY INDICATION OF A PROB WITH ANY OF THE LNDG GEAR. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: FOLLOWUP REVEALED THE MAIN TRUNNION FAILED RIGHT AT THE ATTACH POINT. IT FAILED AFTER FUELING HAD STARTED FOR THE NEXT FLT. G METER REVEALED NO HARD LNDGS IN THE LAST SIX WHICH WAS ALL IT CONTAINED. THIS WAS ONE OF THE NEWER LGTS THIS AIRLINE HAS; SO IS NOT THOUGHT THAT AGE WAS A FACTOR. AT THIS POINT TRUNNION IS BEING CHKED FOR METAL FATIGUE. ONE THOUGHT IS IT WAS SOMEHOW DEFECTIVE CASTING. FAA HAS INVESTIGATED BUT IS TAKING NO ACTION.