On April 8, 2005, at 1055 central daylight time, an Aeronca 7AC, N82051, piloted by a commercial pilot, impacted terrain during a turn back to Wautoma Municipal Airport, Wautoma, Wisconsin, the departure airport. The pilot reported that the engine did not have adequate power during takeoff. Visual meteorological conditions prevailed at the time of the accident. The 14 CFR Part 91 personal flight was not operating on a flight plan. The pilot was uninjured and pilot-rated passenger received serious injuries. The flight was originating at the time of the accident. The pilot stated that about 200 feet above ground level (AGL), they departed the end of runway 08, climbing at 55-60 mph. He began a left turn in order to remain over the airport in case he had to make an immediate landing. He stated that he steepened the bank and lost directional control as the 'high wing' stalled. He lowered the nose and got some control back. He pulled back on the control stick and experienced a secondary stall. The right wing then went downwards and the airplane pitched about 20 degrees downwards. The pilot-rated passenger was seated in the front seat which was not equipped with a shoulder harness. The pilot-rated passenger stated that they departed runway 08 and at or before the runway’s end, about 200-300 feet above ground level, the pilot made a left bank and the airplane dropped. The pilot put the nose down, tried a right bank to avoid a hangar, and the right wing stalled. The airplane impacted the ground with the right wing followed by the engine. The pilot-rated passenger stated that he sustained a "broken nose, broken ankle, compression fracture to L3 and L4 [vertebrae]." The pilot held a commercial pilot certificate with airplane single-engine land and instrument airplane ratings, a private pilot certificate with an airplane multiengine land rating, and a certified flight instructor certificate with an airplane single-engine rating. He reported a total flight time of 5,900 hours at the time of his last airman medical certificate dated January 18, 2005. Federal Aviation Administration (FAA) Airman records show the pilot's weight as 286 lbs and the pilot-rated passenger's weight as 209 lbs. The pilot reported that he determined that there was 3.5 gallons of fuel on board when he did a "normal walk-around" of the airplane prior to departure. The pilot-rated passenger reported that there was 1/4 - 1/2 full of fuel. The Type Certificate Data Sheet for the Aeronca 7AC lists a total fuel capacity of 13 gallons and a maximum weight of 1,220 lbs. The empty weight of the accident airplane was 808.7 lbs. Advisory Circular 91-65, Use of Shoulder Harness in Passenger Seats, states: "...The safety board [National Transportation Safety Board] found that 20 percent of the fatally injured occupants in these accidents could have survived with shoulder harnesses (assuming the seat belt fastened) and 88 percent of the seriously injured could have had significantly less severe injuries with the use of shoulder harnesses. Energy absorbing seats could have benefited 34 percent of the seriously injuries. The safety board concluded that shoulder harness use is the most effective way of reducing fatalities and serious injuries in general aviation accidents." The American Champion Aircraft Corp. issued Service Letter 421, on March 28, 2002, for seat belt retrofit of models 7AC, 7BCM, 7CCM, 7DC, and 7EC airplanes, states: "It has been found that the factory original seat belt restraint system is inadequate. Without the third attach point of a shoulder strap, the crash load on just a lap belt are too great. This letter explores an option to bring the restraining system up to more current standards." An NTSB Pilot/Operator Aircraft Accident Report (6120.1/2) was given to the pilot by the on-scene FAA inspector from the Milwaukee Flight Standards District Office. A 6120.1/2 was then sent three times via certified mail to the pilot to complete and return to the NTSB. A completed 6120.1/2 from the pilot was not received by the NTSB or FAA. A 6120.1/2 from the pilot-rated passenger was received by the NTSB. Inspection of the engine revealed no mechanical anomalies that would have precluded normal operation.