On August 9, 2005, about 0915 Alaska daylight time, a float-equipped Piper PA-18-150 airplane, N717DR, sustained substantial damage during an in-flight collision with terrain, following a loss of engine power during initial climb after takeoff from a lake, about 43 miles northeast of Chickaloon, Alaska. The airplane was being operated by the pilot as a visual flight rules (VFR) personal local flight under Title 14, CFR Part 91 when the accident occurred. The commercial pilot and sole passenger were not injured. Visual meteorological conditions prevailed, and no flight plan was filed. During a telephone conversation with the National Transportation Safety Board (NTSB) investigator-in-charge (IIC) on August 9, the pilot said during takeoff initial climb from a small lake in a float-equipped airplane, the engine lost power. He said he was unable to return to the lake, and the airplane impacted on tundra-covered terrain. He said the airplane sustained structural damage to the right wing, float, and fuselage. During an inspection of the airplane by the IIC on August 11, no obvious reason for the engine's loss of power was discovered. The gascolator was breached during the accident, and about one-half ounce of fuel was collected from the gascolator. The sample appeared to be clear, light blue, uncontaminated, and smelled like avgas. Fuel samples taken from the operator's supply tank were light colored and cloudy, with visible signs of contamination. The airplane's engine was taken to certified aircraft engine repair station by the owner to be rebuilt. During a telephone conversation with the IIC on September 23, the mechanic who disassembled and inspected the engine and carburetor said aside from normal wear, one cylinder was found to be cracked. According to the mechanic who examined the engine and carburetor, nothing was found that would explain the loss of engine power.