On May 22, 2001, at about 1746 eastern daylight time, a Grumman G-73, N142PA, registered to Seaplane Leasing II LLC, operated by Flying Boat Inc, doing business as Chalks International Airlines flight 512, as a 14 CFR Part 121 scheduled international passenger flight, experienced a collapse of the right main landing gear while taxiing to the parking ramp. The airline transport pilot-in-command, commercial pilot copilot, and 17 passengers reported no injuries. Visual meteorological conditions prevailed and a VFR flight plan was filed. The airplane sustained minor damage. The flight originated from Paradise Island, Bahamas, about 51 minutes before the incident. Initial examination of the airplane by the FAA revealed the right main landing gear had separated. Two small preexisting cracks and corrosion was found in the vicinity of the failure location. The Director of Maintenance for Chalks International stated that four landing gear parts were sent to Q.C. Labs for magnaflux and x-ray. The landing gear parts were picked up and brought back to the hangar. The landing gears were prepped, primed, painted, and the landing gear was installed on the incident airplane. On May 22, 2001, N142PA right main landing gear failed while taxiing to the terminal. A review of paperwork from Q.C. Labs revealed that two landing gear parts were rejected because of cracks. A red tag was also attached to the report. " At this time I realized that I had tagged an unserviceable part serviceable by mistake."