Fail‐Safe vs. Safe‐Life Philosophy in V/STOL Design

V/STOL aircraft combine the technological features of rigid‐wing and rotary‐wing aircraft, incorporating many of the structural features of helicopters. A review indicates that structures analysts of conventional aircraft have concentrated on fail‐safe design; while helicopter design engineers have generally been content to rely on component safe‐life design. The two philosophies are examined and an approach to the rational marriage of helicopter and airplane fatigue technologies is suggested, in order to provide an integrated, economically feasible, statistically rational combination of fail‐safe and safe‐life methodology for tilt‐wing and tilt‐rotor V/STOL aircraft.