U-AGREE D3.5 Final Ground Risk Model

Building on the ground risk modelling framework presented in U-AGREE Deliverable D3.2 [2], this deliverable presents the proposed enhancements to the U-AGREE Ground Risk Model, addressing potential improvements of the SORA 2.5 methodology in the context of UAS operations within U-space airspace over urban environments.The document introduces an improved, physics-based and uncertainty-aware assessment of sheltering effects, with particular focus on operations involving UAS with a maximum take-off mass above 25 kg. A probabilistic modelling approach based on Monte Carlo simulations is employed to evaluate building penetration likelihood, explicitly accounting for aircraft type, impact dynamics, material properties, and representative building typologies. This approach enables a more realistic and evidence‑based evaluation of sheltering mitigation and the protection of individuals located inside structures. The results indicate that, for typical Italian building scenarios, penetration likelihood is primarily governed by the weakest elements within the building envelope—most notably windows—rather than by the overall structural strength alone.In addition, the deliverable investigates the obstacle effect in urban environments, quantifying how the presence of buildings and other structures in general can reduce the critical area associated with UAS ground impacts. The analysis, aligned with SORA Annex F principles, demonstrates the differing applicability of this mitigation for fixed-wing and rotorcraft UAS and highlights its potential role as a complementary mitigation measure in dense urban scenarios. Analysis across various urban scenarios demonstrates that fixed-wing UAS configurations offer greater potential for employing obstacle effect mitigation strategies, particularly as a complement to other risk reduction measures.Beyond safety outcomes directly related to crash scenarios, the document further extends the ground risk model by introducing a structured assessment of the severity of other negative effects associated with UAS ground impacts and operations. These include environmental, economic, and reputational impacts, as well as effects arising from other-than-ground-impact events such as noise, visual pollution, privacy, emissions, wildlife disturbance, and security concerns. A qualitative and quantitative scoring framework is proposed to support consistent, transparent severity assessment during the operational planning phase.