This study focused on the development and performance assessment of structural damage detection technology. The targeted application was the OH-58D Kiowa Warrior tailboom. The OH-58 tailboom structure has been experiencing fatigue cracking requiring burdensome scheduled inspections. Newly developed structural health monitoring technologies are desired which could be applied to the OH-58 to eliminate some or all of the manual tailboom inspections. A survey of available OH-58 tailboom documented damage showed fatigue cracking at many locations, implying that any new detection system would need to cover the entire tailboom structure, as opposed to more simplistic hot spot monitoring. In this work nonlinear vibration spectroscopy based damage detection techniques were developed and applied to relevant laboratory test structures including an actual OH-58D tailboom. The results showed the nonlinear techniques are capable of detecting small fatigue cracks, with minimal required sensor-actuators to cover the entire tailboom structure, and offer sensitivity benefits over traditional sensor-actuator intensive linear ultrasonic techniques. An aircraft integration study was also performed, establishing weight and power estimates for several potential operational scenarios.