DURING AN APCH TO LAND, THE PLT LOWERED THE GEAR HANDLE, BUT OBSERVED THAT THE NOSE GEAR LIGHT DID NOT COME ON & THE RIGHT MAIN GEAR LIGHT WAS FLICKERING. CONSEQUENTLY, HE RECYCLED THE GEAR OPERATION. AFTER THAT, HE REPORTEDLY SAW ALL 3 INDICATING DOWN & LOCKED, BUT EXPRESSED THE OPINION THAT THE GEAR OPERATION SEEMED TO TAKE LONGER THAN HE REMEMBERED. DURING THE LANDING, ALL 3 GEAR FOLDED INTO THE WHEEL WELLS. AFTER THE ACCIDENT, OBSERVERS REPORTED THAT THE GEAR HANDLE WAS DOWN, THE FLAP HANDLE WAS IN TH APCH POSITION & THE GEAR CIRCUIT BREAKER WAS POPPED. AFTER THE ACFT WAS RAISED, THE CIRCUIT BREAKER WAS RESET & THE LANDING GEAR WAS CYCLED. THE LEFT MAIN & NOSE GEAR CAME DOWN & LOCKED IMMEDIATELY. THE RIGHT MAIN ALSO CAME DOWN & LOCKED AFTER IT WAS CLEARED FROM A JAMMED GEAR DOOR. THE ACFT WAS ON ITS 1ST FLT AFTER A 100 HR INSPECTION. IT WAS FLOWN BACK TO THE SAME FACILITY & WAS FURTHER CHECKED. REPORTEDLY, PERSONNEL AT THE FACILITY FOUND NO MALFUNCTION OF THE LANDING GEAR SYS.