In the case of Chan et al. v. Korean Air Lines, Ltd., 1988, the U.S Supreme Court ruled that under Article 17 of the Warsaw Convention (an international treaty governing liability for international air accidents), an airline could not be held liable for a passenger's death unless it was caused by an "accident." The court defined an accident as “an unexpected or unusual event or happening that is external to the passenger.” This decision came about after a plane crash in which all passengers died due to suffocation before impact because they were unable to receive oxygen from their masks. The plaintiffs argued that this constituted negligence on part of Korean Air Lines and sought damages. However, since there was no evidence showing any abnormality with either aircraft operation or crew behavior leading up to cabin depressurization and subsequent loss of oxygen supply, it did not meet the definition of 'accident' per Warsaw Convention standards according to majority opinion delivered by Justice Blackmun.

In the dissenting opinion for CHAN et al. v. KOREAN AIR LINES, LTD., Justice Blackmun argued that the majority's interpretation of Article 17 of the Warsaw Convention was too narrow and did not adequately consider its purpose and history. He contended that this article should be interpreted to cover all incidents on board an aircraft where a passenger is injured due to an unexpected or unusual event, regardless of whether it occurred during flight operations as defined by the majority. In his view, this would include injuries caused by terrorist attacks like in this case because they are certainly unexpected and unusual events on board an aircraft. Furthermore, he pointed out that such a broad interpretation has been adopted by several other countries which are parties to the convention.