Redesign of the AH-64 Apache Composite Main Rotor Blade Attachment Fittings to Provide a Field Repair Capability

The development of a new Composite Main Rotor Blade (CMRB) for the AH-64 Apache Longbow Attack Helicopter included a requirement to improve reliability and durability as well as provide enhanced field repair capability. An alternate approach to the design of the blade root attachment was decided upon, which included changing the current single piece stainless steel bushing installation to a two-piece bushing that included a removable wear bushing liner inside the main bushing. This concept was simpler to install and achieved the design performance and rework objectives needed. The bushing and liner combination would be installed using the same ForceMate process as the original bushing installation to meet the fatigue and damage tolerance capability attained in the current blade. This paper will review the current design configuration and the option to replace it with the thinner walled ForceMate outer 17-4 bushing with another ForceMate high interference fit sacrificial aluminum-bronze wear bushing liner expanded into the outer bushing.