On March 12, 2005, about 1230 central standard time, a Cessna TU206G single-engine amphibian airplane , N6211Z, was substantially damaged during a forced landing following a reported loss of engine power while on a visual approch to the Lancaster Airport (LNC), near Lancaster, Texas. The airline transport rated pilot and the passenger were not injured. No flight plan was filed for the flight that originated at the Addison Airport (ADS), near Dallas, Texas, about 1200. Visual meteorological conditions prevailed for the personal flight conducted under 14 Code of Federal Regulations part 91. In a telephone conversation, the pilot stated he did not visually check the fuel tanks prior to take off and he did not recall what the fuel gauges indicated. However, he thought both auxiliary fuel tanks were full, and each main tank was just below full. After departure, he climbed to and leveled-off at an altitude of 2,000 feet msl and flew direct to the Lancaster Airport and prepared to land on Runway 13. As he approached the runway, he began a descent and prepared the airplane for landing, and switched the fuel selector valve from the left main fuel tank to the right main fuel tank. After switching fuel tanks, the engine stopped producing power. The pilot attempted to re-start the engine by switching the fuel selector valve back to the left tank, but was unable to regain engine power. He also said that when he moved the throttle through its full range of motion, there was no response. The pilot stated that he was losing altitude and airspeed, so he made a "tremendous" left turn to a clearing and made a forced landing. The landing gear were not extended and the when the airplane contacted the ground it bounced and the floats separated. The airplane then skidded on it's belly before it came to a rest. The left wing strut collapsed and the wing tip was resting on the ground. The airplane was equipped with an after-market fuel conversion, which included the installation of two 15-gallon tip tanks; one in each wing. He also had a front right side door installed. The pilot stated that when the airplane came to a rest, he exited the airplane from the right front door and observed a "pencil-thin" stream of fuel running down the trailing edge of the wing near the aft doorpost. Examination of both wings revealed the right main and auxiliary fuel tanks were breached from impact. When the system was pressurized, fuel was noted in the auxiliary tank's fuel lines. Both of the main tank's fuel screens were absent of debris. At the time the airplane was recovered, there was no fuel in either tank. The left main and auxiliary tanks were intact, and both of the main tank's fuel screens were absent of debris. At the time the airplane was recovered, approximately nine gallons of fuel were drained from the auxiliary tank and the main tank was empty. Examination of the accident site where the airplane came to rest revealed the grass was discolored yellow below the area of the right auxiliary tank, the inboard section of the right main tank, and the left auxiliary tank. According to an FAA inspector who examined the airplane at the site, when he opened the left auxiliary fuel cap, fuel poured out of the tank and onto the ground. Following recovery to a secure location, the engine was test-run on the airframe, utilizing a test propeller. The engine started immediately and ran at various power settings without interruptions. No mechanical anomalies were noted. The pilot held an airline transport pilot certificate and held numerous type ratings. He reported a total of 24,611 flight hours.