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The original TSO C23b for parachutes came into existence in 1949. The specifications were revised in 1984 to C23c and again in 1994 to C23d. The TSO is a simple two-page document that specifies the requirements for certification. This document also references a performance standard that the parachute must meet. C23b parachutes were tested to standards under National Aircraft Standards Specifications NAS-804. When the TSO was revised in 1984, the specification document was drafted under the auspices of the Society of Automotive Engineers (SAE) S-17 committee as Aerospace Standard AS-8015. When the TSO was revised again in 1994, the revised document became AS-8015b with the original as AS-8015a. Figure 2-3 is a table showing the pertinent points of each of the TSO certifications. For a more thorough study of the documents, refer to Appendix I.

The TSO system consists of two parts. The first is the performance standards listed above. This ensures that the parachute will perform as specified. The second is the production approval, which ensures that the manufacturer is able to produce the parachute as designed and tested. While minor design changes are allowed, any major design change must be submitted to the FAA for approval

Figure 2-3.TSO comparisons.

before implementation. A major change is any that will affect the fit, form, or function of the parachute. For the aspiring rigger, the primary purpose of knowing the TSO system is determining the compatibility of components when assembling the parachute system. This is necessary in order to ensure that, besides fitting together properly, the performance standards are compatible. Under Advisory Circular (AC) 105-2—Sport Parachute Jumping, “the assembly or mating of separately approved components may be made by a certificated and appropriately rated parachute rigger or parachute loft in accordance with the manufacturer’s instructions and without further authorization by the manufacturer or the FAA.” Under these guidelines, there are certain parameters that must be met. One of them is to ensure that “the strength of the harness must always be equal to or greater than the maximum force generated by the canopy during the certification tests.” Full knowledge of the TSO documents ensures that the above requirements are met.