This workshop introduces participants to fatigue and damage-tolerance principles essential for the certification, life-cycle management, and sustainment of modern aircraft structures. Attendees will learn how fatigue crack initiation, crack-growth modeling, and inspection planning ensure long-term structural safety for both metallic and composite airframes. The course covers safe-life, fail-safe, and damage-tolerance approaches, along with regulatory expectations and industry best practices used by civil and military aviation authorities. Drawing on lessons learned from a range of major certification, sustainment, and life-extension programs across the aviation sector, participants will examine how real-world load spectra, maintenance strategies, and inspection intervals influence structural reliability. During the hands-on session, participants will use Paris’ law to predict crack growth under cyclic loading, calculate inspection intervals, and evaluate how mission-spectrum variations affect structural life.