Book excerpt: The report reviews the application of applied fracture mechanics in the design, analysis and qualification of aircraft structural systems. Recent service experiences are cited. Current trends in high strength materials application are reviewed with particular emphasis on the manner in which fracture toughness and structural efficiency may affect the material selection process. General fracture control procedures are reviewed in depth with specific reference to the impact of inspectability, structural arrangement and material on proposed analysis requirements for safe crack growth. The relative impact on allowable design stress is indicated by example. Design criteria, material and analysis requirements for implementation of fracture control procedures are reviewed together with limitation in current available data techniques. A summary of items which require further study and attention is presented.