On July 22, 2010, about 2000 Alaska daylight time, a tailwheel-equipped Cessna 170B airplane, N4590C, sustained substantial damage when it collided with terrain, about 18 miles northeast of Palmer, Alaska. The airplane was being operated by the pilot as a visual flight rules personal local flight under the provisions of Title 14, CFR Part 91. The private pilot received serious injuries, and the sole passenger received minor injuries. Visual meteorological conditions prevailed, and no flight plan was filed. The flight departed the Palmer Airport, about 1830. During a telephone conversation with the National Transportation Safety Board investigator-in-charge on July 27, the pilot said he and the passenger were on a local sightseeing flight. He said he flew up a creek he had not flown up before. The pilot reported seeing an airstrip, and decided he would make a practice approach to it, but had no intentions of landing. He said upon reaching the threshold of the airstrip, he initiated a positive rate of climb, but after flying along the length of the landing area the airplane started to descend. The pilot said he thought they had entered a downdraft, and he applied full power. He said the airplane continued to descend, and he checked the engine controls to make sure they were in a climb configuration, which they were. The pilot said they had made the pass over the airstrip with 20 degrees of flaps, and when it was apparent he couldn't arrest the descent, he added full flaps to slow the airplane and cushion the impact. The airplane collided with rising terrain near the end of the airstrip, and sustained substantial damage to the wings and fuselage. In a written report dated July 27, the pilot reported that proficiency in recognizing potential weather hazards, and greater situational awareness overall, might have helped prevent the accident. The airplane was equipped with a required emergency locator transmitter (ELT), however, it was an older generation ELT that transmitted on 121.5 megahertz, not the newer, digital version that transmits on 406 megahertz. As of February 1, 2009, the search and rescue satellites that receive ELT signals no longer had the capability to receive the older analog 121.5 megahertz ELTs. The 406 megahertz ELTs are received within seconds of activation, and rescuers are notified within minutes of the accident location. In this accident, the pilot and passenger were missing for 2 days, but were able to walk to a trail, despite serious injuries, where a group of all terrain vehicle riders assisted them.