Case C-510/21, Austrian Airlines (First aid on board an aircraft): Judgment of the Court (Third Chamber) of 6 July 2023 (request for a preliminary ruling from the Oberster Gerichtshof — Austria) — DB v Austrian Airlines AG (Reference for a preliminary ruling — Air transport — Montreal Convention — Article 17(1) — Liability of air carriers for death or injury sustained by passengers — Concept of ‘accident’ — Bodily injuries aggravated by first aid administered following an accident that took place on board an aircraft)