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Novel architectures and technologies carry with them an uncertainty related to their reliability and associated safety risk. Existing safety assessment methods involve determining the severity of discrete functional failure and the corresponding probability. However, with the advent of novel aircraft architectural and operational concepts, traditional methods of establishing severity and probabilities failures are found lacking due to the scarcity of available data. The current work proposes a safety assessment method that uses architecture-specific performance models along with continuous functional hazard assessments to inform hazard severity. The probability of failures is determined using a Bayesian framework that does not falter when data is scarce. Taken together, it is expected that this new proposed methodology will enable a more accurate safety assessment of novel aircraft architectures and technologies. A safety assessment of an electric propulsion system powered by a fuel cell is conducted using the proposed methodology to serve as a proof of concept. Nomenclature C-FHA = Continuous Functional Hazard Assessment λ = Failure rate (per flight hour) ȳ = Available failure data a = Compliance action (decision) X = True value of compliance finding (unknown) δ = Decision rule L(X, a) = Loss function

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A key enabler for sustainable growth of aviation is the mitigation of adverse environmental effects. One area of concern is community noise exposure at large hub airports serving growing population centers. Traditionally, community noise exposure is computed using noise contours around airports, which requires knowledge of a large dataset pertaining to the air traffic operations at the airport of interest. Due to the underlying variability in real-world aircraft operations, numerous assumptions need to be made which adversely affect the accuracy of the model. Reduced-Order Modeling (ROM) methods provide a new framework for the retention of a large number of these parameters, thus improving model speed and accuracy. In this work, a proper orthogonal decomposition in conjunction with a response surface methodology-based surrogate model is used to create a rapid noise assessment model. Validation is performed against results obtained from the aviation environmental design tool with quantitative error metrics and visual contour comparisons. Obtained results are encouraging and motivate further work in this area with other ROM methods. ROM based models for noise assessment expand the solution space for noise mitigation strategies which can be evaluated, and therefore can lead to novel solutions which cannot be found with traditional modeling methods.

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