Certification by Simulation of an eVTOL: Credibility Analysis of Simulation Model Using Uncertainty Quantification

A methodology to assess the credibility of flight simulation models for certification by simulation is developed. Aim of the research is to determine if the model, despite its uncertainties, can reliably predict handling quality compliance for specific flight tasks. Applied to a lift+cruise VTOL model performing a deceleration-to-hover manoeuvre, this is achieved by quantifying the impact of input parameter uncertainties on predicted handling qualities and evaluating the envelope of the resulting uncertain aircraft transfer functions - scaled by a confidence ratio - against maximum unnoticeable added dynamics boundaries. While longitudinal dynamics largely remained within MUAD limits, indicating model's credibility for those aspects, vertical axis dynamics coupled with longitudinal inputs in some uncertain configurations exceeded these limits, correlating with observed flight test variability. This work ultimately presents a structured approach to model uncertainty quantification for HQ certification by simulation, bridging the gap between model input uncertainty and prediction confidence, and supporting safer VTOL development.