A Method to Reduce Rotorcraft Development Risk by Integrating Historical Quantitative Risk Assessment into Fault Tree Models

Fault Tree Analysis (FTA) is performed during vertical lift product development, but only an estimation of the probability of component failures can be made at that point of product design and development. Estimation of component failure probability during FTA typically does not account for component aging, installation effects, maintenance actions, and other factors encountered in operation, which can lead to under prediction, resulting in identification of hazards during test, evaluation, and deployment. Quantitative Risk Assessment (QRA) is typically performed during fleet operation. Efforts to eliminate hazards or mitigate risks are less effective and much more costly in this phase of the product lifecycle compared to proactively addressing hazards early in development. If the risk of failures could be accurately predicted earlier, hazards could be addressed early in the process. Such a method is presented here, where historical QRA for similar hazards can be integrated into the FTA. This would reduce cost, schedule, and safety risks by reducing the risk of failure during ground and flight test and in fleet operation.