Assessing Helicopter Safety with Respect to Component Fatigue: A Procedure Based on Statistical Methods of Data Analysis Requiring a Catastrophic Failure Rate of less than I0–3 after 10,000 flying hours Available to Purchase

A distinction is drawn between reliability, and aircraft safety, which may be termed a subdivision of reliability. Some principles arc laid down that will enable the aircraft development programme to proceed upon the necessary lines to meet requirements for safety. The procedure uses statistical methods of data analysis because at the present state of knowledge these provide the sole means for the mathematical determination of reliability from the safety aspect. As safety requirements have not yet been specifically stated, a suggestion has been made that aircraft safety should require a catastrophic failure rate of less than 10–3after 10,000 flying hours. It has been shown how a requirement of this type may be met, but the methods are sufficiently flexible for adaptation to any requirement that may be considered necessary in the future.