: Unlike earlier systems that allowed carriers to avoid liability by proving they took "all necessary measures," MP4 established a system of strict liability . The carrier is liable for damage or loss to cargo regardless of fault, with only a few specific exceptions (such as inherent defect in the cargo or an act of war).
In the insurance industry, "1975 MP4" is still referenced when discussing historical liability frameworks or policies that cover operations in countries that have not yet ratified the 1999 Montreal Convention. It remains a cornerstone for understanding the evolution of aviation risk management and legal disputes involving international air carriage. US Manual of International Air Carriage 41975mp4
The international legal framework for aviation began with the Warsaw Convention of 1929 , which established uniform rules for passenger and cargo liability. By the 1970s, many of these rules were outdated. In September 1975, a series of "Additional Protocols" were signed in Montreal to update this system. : Unlike earlier systems that allowed carriers to