Development of a Fatigue Life Management System for Dynamic Components on the OH-58D Kiowa

This paper discusses Bell Helicopter's development, validation and implementation of a Fatigue Life Management (FLM) system for the U.S. Army's OH-58D aircraft. Bell Helicopter has been working under a contract from the U.S. Army Armed Scout Helicopter (ASH) Project Management Office (PMO) to develop, validate and demonstrate a usage-based fatigue damage calculation methodology for a number of life limited components selected by both the Army and Bell. Regime Recognition Algorithms (RRA) and Fatigue Damage Calculation (FDC) methodology and software necessary to implement FLM for the aircraft were developed using data recorded from OH-58D flight tests and from data recorded by Health Usage Monitoring System (HUMS) devices installed on these aircraft. Methods for accounting for Reliability based on the new approaches for fatigue life management were also explored as part of the FDC methodology. The paper will also discuss the FLM implementation strategy and will review how the Army's overall goals will be met through a controlled implementation.