The aircraft industry consists primarily of original equipment manufacturers (OEMs) responsible for the design and construction of new aircraft. These aircraft are built and certified for operation under a set of federal aviation regulations (FARs). Once approved, a valid type certificate (TC) is issued for the particular aircraft and model(s) being certified. However, a substantial number of third-party (non-OEM) modifications to existing aircraft are being performed and are also typical of the industry. Such modifications are built and certified to the same FARs; however, the actual approval in this instance takes the form of a supplementary type certificate (STC) for the particular modification to specific aircraft TCs. Modifications may include systems changes, performance enhancements, noise abatements, structural modifications, and so on. Common to the TC and the STC design and certification processes is the need to develop the databases used in support of the various analyses and testing deemed necessary in the process of showing compliance with the regulations. By contrast, the TC program is centered on synthesizing a complete aircraft design that matches certain performance criteria, whereas the development of structural modifications in support of an STC merely requires an understanding of the final set of parameters that dictated the design of the aircraft in its original configuration. The OEMs typically invest substantial amounts of resources in developing the databases and consider these highly proprietary. The database is substantial and may encompass several parameters, including, but not limited to a complete description of the structural arrangements, systems description, mass distribution in the aircraft for all operational conditions (center of gravity, payload distributions, fuel distributions, etc.); structural stiffness representa- tion; landing gear characteristics (hydraulic damping, oleo stiffness, tire stiffness, wheel inertias, etc.); design envelope (speed, altitude, Mach range, etc.); control-surface authority, location, operation, performance and stability data; yaw damper and autopilot authority; and distributed aerodynamic loading characteristics.

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Engineering Solutions in Support of STC_JOA