What material should be used for a repair of a 1-1/4 inch lower horizontal stabilizer streamlined brace?

Using an outside sleeve of at least the same gauge with a minimum length of 9.128 inches for a repair of a lower horizontal stabilizer streamlined brace is correct for several reasons. The structural integrity of the brace is essential for the overall stability and performance of the aircraft. Aviation regulations and best practices require repairs to be made with materials that maintain the original strength and characteristics of the aircraft structure.

Choosing an outside sleeve of the same gauge ensures that the repair will not undermine the load-carrying capability of the brace. By specifying a minimum length of 9.128 inches, this option ensures that the sleeve adequately overlaps the damaged section to distribute loads over a sufficient area, preventing stress concentrations that could lead to failure.

This approach adheres to guidelines set forth in Part 23 and 25 of the Federal Aviation Regulations, which outline the acceptable methods for structural repairs. Structural components must maintain their strength and aerodynamic properties, and using a sleeve helps to ensure these properties are preserved, which is critical in aviation where safety is paramount.