Condition (Usage) Based Maintenance and SLL Computation using Flight Regime Recognition Algorithm

Condition (Usage) Based Maintenance (CBM) function is becoming a standard and classical investigation topic for Original Equipment Manufacturers (OEM) for many reasons. Significant benefits can be earned by developing and using such functions: Better knowledge of the customer's usage of the helicopters, improvements in the building of the Design Usage Spectrums (DUS) for both high cycle fatigue mode (time ratio spent and occurrences of flight regimes) and low cycle fatigue mode (start/stop cycles, landing/take-off cycles, torque cycles, -), better understanding of the customer's own fleet's management, and of course maintenance optimization. In order to achieve this target and in particular the maintenance burden reduction, AH has developed a complete end-to-end CBM function proven to be efficient for customers. This paper intends to describe briefly the general concept already published, recall the expected benefits previously evaluated on H225, and focus deeper on the validation of the Flight Regime Recognition (FRR) Algorithm, allowing to confirm and reinforce the robustness of the function proposed. It details the means proposed by AH to validate the regime recognition and the potential credit, as well as the cautions to be taken when implementing such a function. General continued airworthiness and certification issues are also included in this paper, as required and proposed by AMC 29.1465 and AC29-2C MG15.