Damage tolerance principle
Impact Damage Tolerance of Aeronautical Composite Structures

The concept of damage tolerance was introduced in the 1970s for civil aircraft structures. These requirements are explicitly expressed by European standard JAR 25.571 : "the damage tolerance evaluation of the structure is intended to ensure that should serious fatigue, corrosion or accidental damage occur within the operational life of the airplane, the remaining structure can withstand reasonable loads without failure or excessive structural deformation until the damage is detected" or by American standard FAR 25.571