The endorsement that writes back into an aviation liability policy the war and hijacking perils excluded by clause AVN 48B, under a separate sublimit.
Clause AVN 48B excludes from the aviation policy the perils of war, strikes, riot, hijacking, sabotage and acts of terrorism, an exclusion so broad that an airline stopping there would not be insurable in the eyes of its regulators or its lessors. The AVN 52 endorsement writes those perils back, not in full but under a sublimit of its own, applying per occurrence and in the aggregate, with a seven day cancellation notice that lets the underwriter withdraw if the geopolitical picture worsens, and automatic termination on open conflict between nuclear powers. Its successive versions, up to AVN 52E and its variants, mainly served to reset the third party liability sublimit after September 11, 2001. The problem solved is a peril nobody wants to cover without limit and nobody can do without, which a short sublimited endorsement makes bearable on both sides.
In the days following September 11, 2001, reinsurers exercised the seven day notice and canceled third party war liability cover worldwide. It was reinstated under AVN 52 with a sublimit of 50 million dollars per airline, far below prevailing civil limits, and governments opened temporary public backstops to fill the gap.
AVN 52E, extension de garantie guerre aviation