HISTORY OF FLIGHT On August 8, 2010, about 1415 eastern daylight time, an amphibious Quest Aircraft Kodiak 100, N917CM, was substantially damaged during landing on Brandy Pond (5ME), Naples, Maine. The certificated airline transport pilot (ATP) and commercial pilot were not injured. Visual meteorological conditions prevailed, and no flight plan was filed for the personal flight, which was operated under the provisions of Title 14 Code of Federal Regulations Part 91. The purpose of the flight was for the two pilots to take turns practicing for a Federal Aviation Administration (FAA) practical test for Part 135 certification, which was scheduled to be administered the following week. The commercial pilot flew the first leg from 5ME to Auburn/Lewiston Municipal Airport (LEW), Lewiston, Maine, where they stopped to fuel the airplane and eat. The ATP then flew for approximately one hour before returning to 5ME. After discussing the boat traffic and winds at 5ME, the pilots elected to conduct a landing to the northwest with a left crosswind. The ATP, who was flying the airplane during the landing, stated that there were many boats on the lake, and though the water was rough from the boat wakes, they were not unaccustomed to operating in such conditions. The ATP configured the airplane for a normal water landing, and stated that the right float contacted the water first, followed by the left float. The airplane then veered to the left and the ATP applied rudder and aileron to correct. The airplane rolled onto the right float, and came to rest inverted. The commercial pilot stated that just prior to touchdown, a gust of wind lifted the left wing. The right float contacted the water, and the airplane suddenly tipped over. She stated that the landing was conducted with a slight crosswind. She believed that the winds on the lake were no more than 3-6 knots, based on her observation of the wave levels, and that the roughness was caused by boat wakes. A witness located on a boat near the airplane's touchdown point captured video footage of the airplane from just prior to touchdown, until after the airplane nosed over. The video depicted the airplane touching down in a level attitude. The left float appeared to rise out of the water shortly after touchdown, and several times after the initial touchdown. Approximately 10 seconds after the initial touchdown, the left float rose completely out of the water, the right wing contacted the water, and the airplane nosed over. WRECKAGE AND IMPACT INFORMATION Examination of the airplane by an FAA inspector revealed substantial damage to the right wing, right horizontal stabilizer, and right elevator. Both left and right forward float struts were separated at their attachment fittings. The fittings were retained for further examination at the NTSB Materials Laboratory. PERSONNEL INFORMATION The ATP held an airline transport pilot certificate with several type ratings, as well as ratings for airplane multiengine land and airplane single engine sea; and a flight instructor certificate with ratings for airplane single and multiengine, and instrument airplane. He reported 30,000 total hours of flight experience, 18 hours of which were in the accident airplane. His most recent FAA second-class medical certificate was issued in May 2010. The commercial pilot held a commercial pilot certificate with ratings for airplane multiengine land and airplane single engine sea, and a flight instructor certificate with ratings for airplane single engine and instrument airplane. She reported 4,737 total hours of flight experience, 17 hours of which were in the accident airplane, and 2,500 hours of which were in seaplanes. Her most recent FAA first-class medical certificate was issued in September 2009. Both the ATP and commercial pilot received 10 hours of flight training in the accident airplane subsequent to the float installation. The training included both water and land operations, and was completed on August 2, 2010. AIRCRAFT INFORMATION According to FAA records, the airplane was manufactured in 2009 and registered to the owner in July 2010. It was equipped with a Pratt and Whitney PT6A-34, 750-horsepower turbo-propeller engine, and a Hartzell HC-E4N-3P four-bladed propeller. The airplane had accumulated 54 total flight hours at the time of the accident. Its most recent annual inspection was completed on September 23, 2009. The airplane was manufactured with fixed tricycle landing gear, and received Supplemental Type Certificate (STC) approval from the FAA for installation of Wipaire Wipline 7000 amphibious floats in June 2010. The float installation was completed on July 30, 2010, and the airplane had accumulated approximately 30 hours of flight time since the installation. METEOROLOGICAL INFORMATION The 1415 weather observation at LEW, located approximately 14 nautical miles northeast of the accident location, included winds from 180 degrees at 10 knots with gusts to 14 knots, 10 statute miles visibility, clear skies, temperature 26 degrees C, dew point 12 degrees C, and an altimeter setting of 30.03 inches of mercury. ADDITIONAL INFORMATION The left and right front float attachment fittings were examined at the NTSB Materials Laboratory in November, 2010. The upper part of each fitting was attached to the engine mount. The lower part of each fitting was in the form of a tab approximately .75 inches thick, 1.4 inches wide, and 1.7 inches long. The forward float struts were attached to the fittings by bolts which passed through holes in each tab. Examination revealed that the tabs from both fittings were fractured and separated, and exhibited signatures consistent with ductile overstress. Residual permanent deformation indicated that the tabs from both fittings separated under bending loads, with elongation of the bolt hole on the right side of the tab, and a compression lip at the edges of the upper left side bolt holes. There were no indications of any pre-existing damage or defect such as fatigue cracking or corrosion.