On January 24, 2004, at 1330 eastern standard time, an Aeronca 7AC, N1087E, piloted by a private pilot, sustained substantial damage during an in-flight collision with electrical transmission wires and subsequently an ice-covered Pine Lake, near Prairieville, Michigan. Visual meteorological conditions prevailed at the time of the accident. The personal flight was operating under the provisions of 14 CFR Part 91 without a flight plan. The pilot sustained serious injuries and his passenger was uninjured. The local flight departed the Plainwell Municipal Airport (61D) at 1315. According to a pilot interview and his written statement, the accident occurred when a flight of two airplanes was attempting to land on the frozen lake. The accident airplane was following the other airplane during final approach to the lake. The pilot of the preceding airplane announced over the radio "watch for wires" just prior to successfully landing on the lake. The accident pilot stated his airplane's landing skis caught all three transmission wires as he attempted to climb away from the obstacle. He reported the landing skis collapsed during the subsequent hard landing and the airplane slid nose-down for approximately 100 feet. The accident pilot stated the transmission wires were not marked and their support poles were positioned in a forested area adjacent to the lakeshore.