On October 15, 2004, about 1300 Alaska daylight time, a tundra tire-equipped Piper PA-18 airplane, N9146D, sustained substantial damage when it stalled and descended to the runway during the base-to-final turn for landing at Kalmbach Airstrip, located about 2 miles northwest of Wasilla, Alaska. The airplane was being operated as a visual flight rules (VFR) local area personal flight under Title 14, CFR Part 91, when the accident occurred. The airplane was operated by the pilot. The private certificated pilot, and the sole passenger, were not injured. Visual meteorological conditions prevailed. The flight originated at the Wasilla Airport, about 1230. No flight plan was filed, nor was one required. During a telephone conversation with the National Transportation Safety Board (NTSB) investigator-in-charge (IIC), on October 15, the pilot reported that he was maneuvering for landing on runway 03 at the Kalmbach Airstrip. The airstrip has a gravel surface on a 030/210 magnetic orientation, and is about 3,000 feet long and 100 feet wide. The pilot indicated that he was making a left turn from a base leg entry to the final approach course for landing, when the airplane stalled from about 75 feet above the ground. He leveled the wings before runway contact, and the airplane collided with the runway surface in a wings-level attitude. The main landing gear collapsed, and the airplane received damage to the left wing lift struts, the left wingtip, and the propeller. In the Pilot/Operator Aircraft Accident Report (NTSB Form 6120.1) submitted by the pilot, the pilot reported that during the left turn from base leg to final, he was about 100 feet above ground level (agl) and over the threshold of the airstrip. He indicated that he added engine power to arrest his descent, but the engine rpm did not respond for about 3 to 4 seconds. Within that time period, the airplane stalled and descended to the ground.