On November 8, 2011, about 1415 Pacific standard time, an Air Tractor AT-602, N325BR, sustained substantial damage during a forced landing following a loss of engine power during takeoff initial climb from a private airstrip near Williams, California. The airplane was registered to and operated by Pacific Valley Aviation, Arbuckle, California, under the provisions of Title 14 Code of Federal Regulations Part 91. The commercial pilot, sole occupant of the airplane, was not injured. Visual meteorological conditions prevailed and no flight plan was filed for the local aerial observation flight, which was originating at the time of the accident. During a telephone conversation with the National Transportation Safety Board (NTSB) investigator-in-charge (IIC), the pilot reported that during takeoff initial climb from a private airstrip at an altitude of about 150 feet above ground level (agl), the engine began to surge along with erratic propeller revolutions per minute (RPM) and engine torque readings on the engine instruments. The pilot initiated a 180-degree turn back to the departure airport and about half way through the turn, the engine lost complete power. He then initiated a forced landing in the direction of the departure airport. Subsequently, the airplane landed hard on the northern part of the departure airport and came to rest upright. Examination of the airplane by company personnel revealed that both wings and fuselage were structurally damaged. The wreckage recovery personnel reported a fuel amount of more than 30 gallons was removed from the wreckage prior to transport. Postaccident examination of the airplane by the NTSB IIC revealed no anomalies with the airframe. Continuity from the cockpit engine controls to the engine was established. The engine visually appeared to be intact and undamaged, with all fuel lines, oil lines, and pneumatic lines intact and secure. The engine was removed and shipped to Pratt & Whitney Canada, Montreal, Canada, for further examination. Examination of the turbine engine was conducted at the facilities of Pratt & Whitney Canada, Montreal, Canada, under the supervision of the NTSB IIC. A borescope inspection revealed no evidence of any internal damage to the engine. The engine was installed on an engine test stand and subsequently run. The engine functioned normally throughout a various range of power settings. The propeller governor and overspeed governor were tested on a test bench. Both functioned normally with test results consistent with normal field adjustment of both units. Review of the airplane maintenance records revealed that the engine and airframe underwent their most recent 100-hour inspection on July 15, 2011, at an engine total time since new of 1,980.4 hours.