On January 3, 2015, about 1650 Pacific standard time, a Cessna 172D, N2948U, experienced a partial loss of engine power and collided with a power line during a forced landing near Fresno Chandler Municipal Airport, Fresno, California. The private pilot and a passenger were not injured; the airplane sustained substantial damage to the left wing and the tail section. The airplane was registered to an individual and operated by the pilot under the provision of 14 Code of Federal Regulations (CFR) Part 91 as a personal flight. Visual meteorological conditions prevailed for the flight, and no flight plan had been filed. The flight originated from Oceano County Airport, Oceano, California at 1600. The pilot reported that he had flown from Fresno earlier in the day and was on the return trip back from Oceano. About 40 minutes after takeoff, the pilot began the descent toward Fresno Chandler Municipal Airport. During the descent, with the airplane about 3 miles from the runway, the engine experienced a partial loss of power. In response, the pilot set the mixture control to the full rich position and applied carburetor heat. Despite his attempts, the engine power dropped to idle. The engine would momentarily regain power when the pilot manipulated the throttle lever, but the airplane could not maintain altitude. The pilot made a forced landing in a nearby open field. The airplane subsequently impacted an unseen set of power lines before landing in the field. The empennage and the left wing sustained substantial damage. The pilot stated that at the time of the accident, the fuel gauge in the cockpit indicated that the left wing fuel tank was empty, but the right wing fuel tank had between 1/4 and 1/2 of the fuel quantity in it. A post accident examination by a Federal Aviation Administration (FAA) inspector was conducted on the engine and the fuel system. Inspection of the fuel strainer revealed no signs of fuel. The main fuel line from the fuel strainer to the carburetor was removed, and no fuel was evident. Both fuel tanks were inspected and no fuel was found. Examination of the carburetor by the National Transportation Safety Board (NTSB) investigator revealed that the carburetor was intact and undamaged. The throttle control arm was intact and moved from stop to stop by hand. The carburetor was disassembled and examined internally. The accelerator pump functioned normally when the throttle arm was actuated by hand. The metal floats were intact and undamaged. The needle valve and needle valve seat were intact and undamaged. The carburetor float bowl was free of debris. No residual debris was found within the float bowl. No debris was observed within the carburetor mixture metering sleeve.