Inspection And Repair Of Advanced Composite Airframe Structures For Helicopters

A program was conducted to develop and demonstrate techniques for the inspection and repair of advanced composite airframe structures in the Army aircraft field environment. The study was based on advanced structures designs and design concepts incorporated in Sikorsky Aircraft's candidate for the Advanced Composite Airframe Program (ACAP), the BLACK HAWK Helicopter Composite Rear Fuselage (CRF), and the BLACK HAWK Helicopter External Stores Support System (ESSS). Ten methods of nondestructive inspection having potential applications to advanced composite airframe structures were evaluated. Tests were conducted to assess the structural effects and visual inspectability of large subsurface flaws in primary composite structures. Field repair methods were developed for primary airframe structures. Test panels were fabricated and ballistically damaged. The damaged test panels were repaired and statically tested to failure. The strength of the repaired panels was compared to the strength of undamaged panels, and the quality and feasibility of the repairs were evaluated. A demonstration of modular airframe repair was conducted using a tool proofing model of the BLACK HAWK CRF. The strength of the repair joints was verified through static testing. R&M guidelines were established for the design of advanced composite airframes.