Lead Cracks and an Example of Fatigue Lifing

Many years of QF on metallic airframe components from service and FSFTs have consistently shown that the dominant fatigue cracks (those first leading to failure) grow in an approximately exponential manner. These observations have lead to the Lead Crack Fatigue Lifing Framework (LCFLF). The LCFLF supporting the simplified lifing method is considered to provide conservative fatigue life estimates, albeit that considerable engineering expertise is required for a judicious choice of the FCG curve parameters.