On September 9, 2013, about 1115 Pacific daylight time, a Grumman American Avn. Corp. AA-1C, N9923U, was substantially damaged during landing at the Hemet-Ryan Airport (HMT), near Hemet, California. The airplane was registered to First Flight Corp., San Diego, California, and operated by the pilot under the provisions of Title 14 Code of Federal Regulations Part 91. The private pilot and his passenger sustained minor injuries. Visual meteorological conditions prevailed and no flight plan was filed for the personal flight. The cross-country flight originated from Gillespie Field, San Diego, about 1030, with an intended destination of HMT. The pilot reported that while on downwind for runway 23, smoke entered the cabin, and that his passenger thought the engine was on fire. The pilot stated that he immediately shut down the engine and declared an emergency by stating his intentions and the nature of the emergency on the common traffic advisory frequency (CTAF). As the pilot was turning towards the runway, he observed a helicopter on the active runway and transmitted "helicopter on the runway, I have to land now." The pilot stated that he stopped the turn and slowed the airplane. As the helicopter was lifting off of the runway, the pilot "tried to make the runway." Subsequently, the airplane landed hard on runway 23. The pilot added that during the approach to landing, he was "too low and too slow." Examination of the airplane by a Federal Aviation Administration (FAA) inspector revealed that the left and right wings were structurally damaged. A burnt wire originating from the field terminal of the voltage regulator was observed.