Downing of Flight PS725 on January 8, 2020, was an extremely painful incident that brought with it numerous legal challenges. Although the Iranian government’s negligence as a third party in this incident is clear, Ukraine International Airlines failed to prove it was not negligent in the case of "S. et al. v. Ukraine International Airlines" and, according to Judgement No. 3303, the Ontario Court ruled that its liability for damages was unlimited. The Review of the contents of this judgment raises questions such as whether the behavior of the Ukrainian Airline on the night of the accident can be considered as negligence? In addition, having regard to the third party's negligence in this incident, another question is that why the third party negligence defense was not accepted by the court in this case?
Assessment of the court's grounds for finding the Ukrainian airline at fault leads to the conclusion that, contrary to the court's statement that the criterion for finding fault is the behavior of a reasonable person in similar circumstances, the court did not consider this criterion because, during the period between the Iranian missile attack and the downing of the Ukrainian plane, 55 airlines behaved similarly to the Ukrainian airline and had effectively assessed the risk of flying during the aforementioned period as acceptable. Also, the third-party negligence defense was not accepted by the court due to the Ukrainian airline being found at fault and due to the presence of the word "solely" in Article 21, paragraph 2, subparagraph b of the Montreal Convention, which seriously casts doubt on the effectiveness of this defense.