On July 31, 2021, about 1130 central daylight time, a Piper J3C-65 airplane, N42522, was substantially damaged when it was involved in an accident near Hartford, Wisconsin. The flight instructor was fatally injured and the pilot receiving instruction was seriously injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 instructional flight. The pilot receiving instruction reported that they were practicing takeoffs and landings from runway 27 at the Hartford Municipal Airport (HXF) and had performed about 10 before the accident occurred. On the accident takeoff, when the airplane reached 400-500 ft agl, the instructor said, “engine failure, turn around for 09”. The instructor did not state if it was an actual or simulated engine failure. Both pilots were on the controls at this time and started a turn for runway 9 when the airplane entered a “graveyard spin.” He remembered about 1 to 2 seconds of the spin and had no further recollection of the accident. The airplane impacted a bean field about 1,100 ft west of the departure end of runway 27. Based on airframe damage signatures, the airplane impacted in a left-wing low, nose low attitude, with the airplane coming to rest about 35 ft west of the initial impact point. A postaccident examination of the airplane confirmed flight control system continuity from the cockpit controls to all control surfaces. There were no separations in any of the flight control cables. The left-wing spars were broken at the wing root, but the remainder of the wing was predominately intact. Both left lift struts were bent and remained attached at the fuselage and wing. The right wing remained attached to the fuselage with little damage. Both right lift struts were bent and remained attached to the fuselage and wing. The forward lower fuselage at the firewall was pushed rearward. The engine remained attached to the fuselage. One propeller blade was bent aft and under the engine, and the crankshaft was partially separated just aft of the propeller flange. Examination of the engine confirmed internal continuity, and both magnetos provided a spark on all spark plug leads. All spark plugs were examined, and no anomalies were noted. The front of the cabin area was crushed rearward and upward at the firewall, but the deformation was limited to the area where the front pilot would have placed their feet. The top of the instrument panel was bent forward, consistent with the front pilot impacting it during the accident sequence. The flight instructor in the front seat suffered fatal injuries attributed to blunt force trauma to the head by the medical examiner. The student pilot in the rear seat sustained serious head and torso injuries, including loss of consciousness, lumbar and rib fractures, and broken ulna and radius. When originally manufactured, the airplane was equipped with lap seat belts but did not have shoulder harnesses installed and no shoulder harnesses had been retrofitted to the airplane. A National Transportation Safety Board survival factors specialist used anthropometric data, photographic evidence, manufacturer drawings, and measurements taken from the accident scene to determine the occupant trajectories in the event of an accident both with and without shoulder harnesses installed. The study showed that both occupants were likely to impact their head and upper torso on structures located within the airplane’s cabin when restrained only by a lap belt. The addition of an upper torso restraint (shoulder harness) would likely have lessened the severity of the injuries by altering the body trajectories such that impact forces with objects within the cabin were eliminated or lessened. Effective July 18, 1977, Section 23.785 of 14 CFR Part 23 required all normal aircraft, for which application for type certificate was made on or after July 18, 1977, to have approved upper torso harnesses for each front seat. Section 14 CFR Part 91.205(b)(14) required all small civil airplanes manufactured after December 12, 1986, to have an approved upper torso harness for all seats. However, aircraft that were manufactured before that date were not required to have an upper torso restraint installed. In 1981 the NTSB initiated a multi-part general aviation crashworthiness program (NTSB Safety Report SR8301). The NTSB examined accidents and their effects on the occupants and airplane structure for the purpose of upgrading occupant protection design standards. In the second report in this program (NTSB Safety Report SR8501), the NTSB found that 20 percent of the fatally injured occupants in those accidents could have survived with upper torso harnesses (assuming the seatbelts were fastened properly) and 88 percent of the serious injuries could have significantly less severe injuries with the use of upper torso harnesses. The NTSB concluded that upper torso harness use was the most effective way of reducing fatalities and serious injuries in general aviation accidents. As a result of the program the NTSB issued safety recommendation A-85-124 recommending the FAA issue an advisory circular to provide information on crash survivability aspects of small aircraft. In March 1987, Technical Standard Order (TSO) C114, “Torso Restraint Systems,” was issued by the FAA. The TSO prescribed the minimum performance standards that upper torso harness restraint systems must meet to be identified with a TSO marking. Then on September 19, 2000, the FAA issued policy statement number ACE-00-23.561-01, “Methods of Approval of Retrofit Shoulder Harness Installation in Small Airplanes.” This provided guidance to make it easier to retrofit shoulder harnesses in certificated aircraft by making it a “minor change” if the following criteria were met: The aircraft was manufactured before July 19, 1978, for front seats and Dec. 12, 1986, for rear seats. TSO-C114 belts were used. No drilling or welding had been performed. The mechanic doing the install consulted Advisory Circular 43.13-2A, Chapter 9, for information on restraint systems, effective restraint angles, attachment methods, and other details of installation. The installing mechanic made an entry in the aircraft's maintenance log. If drilling or welding was required, then a supplemental type certificate or field approval was required to make the modification. At the time of this accident several manufacturers offered shoulder harness kits that could be retrofit to the accident airplane under supplemental type certificate.