Alternative Means of Compliance for Composite Structural Fatigue Certification of Small General Aviation Aircraft

Abstract

As the future of the general aviation industry seems to be improving, a cultural paradigm shift may be imminent with the development of an advanced, revolutionary transportation system within the United States. One significant problem with this idea has been shown to be the fatigue structural certification of small, composite airplanes. By implementing a fatigue safe-life certification method for small general aviation aircraft, reduced certification program costs may be obtained while maintaining their reliability and capability. Although acceptable only when certifying aluminum aircraft, the current method has been modified here to incorporate the use of discontinuous composite materials on a defined small general aviation aircraft. Through this modification, a simplified method for the determination of the stress-cycle curve and a new “scatter factor” methodology based on the composite material properties have been developed. By using fiberglass reinforced polyester as an example composite material family, the safe-life of small general aviation aircraft relative to composite fatigue can be determined.