Category: Aviation insurance · Reviewed by Matt Bartlett, Director · Founder · Last reviewed 2026-06-05
The Montreal Convention 1999 is the international treaty governing the liability of air carriers for international carriage by air, replacing the older Warsaw Convention regime for state parties; it imposes strict liability up to a per-passenger ceiling for death and bodily injury, with unlimited liability above the ceiling subject to absence-of-fault defences.
Category: Aviation insurance Also known as: Montreal Convention, MC99, Convention for the Unification of Certain Rules for International Carriage by Air First codified: signed Montreal, 28 May 1999; entered into force 4 November 2003 Related legislation: Carriage by Air Act 1961 (as amended) [1]; Carriage by Air Acts (Implementation of the Montreal Convention 1999) Order 2002 [2]; EU Regulation 785/2004 (retained law) [3]
The Montreal Convention 1999 (‘MC99’) is the international treaty that governs the liability of air carriers for the death of or bodily injury to passengers, for loss or damage to baggage, and for loss or damage to cargo in respect of international carriage by air. It modernised and consolidated the older Warsaw Convention 1929 regime and its various protocols and supplementary instruments, providing a single coherent framework with limits expressed in IMF Special Drawing Rights (SDRs) and updated periodically by the ICAO Council under Article 24 [4][5].
The Convention was concluded under the auspices of the International Civil Aviation Organization on 28 May 1999 and entered into force on 4 November 2003 once 30 instruments of ratification had been deposited. The UK ratified the Convention in 2002 and it took effect for UK international carriage on 4 November 2003. By 2026 the Convention is in force in over 140 state parties, covering the great majority of international scheduled commercial air traffic [4][6].
The Convention is the principal legal framework against which modern aviation passenger liability insurance is structured. Insurance wordings respond to the carrier’s actual legal liability, which in most international air carriage cases means liability under the Montreal Convention. The strict-liability ceiling under Article 21 — currently 128,821 SDRs per passenger following the 2024 ICAO Council revision effective from 28 December 2024 — establishes a key data point for reserving and capital modelling [4][5].
The Convention is incorporated into UK law through the Carriage by Air Act 1961 (as amended by the Carriage by Air and Road Transport Act 1979 and the Carriage by Air (Parties to Convention) Order, with the Montreal Convention specifically given effect by the Carriage by Air Acts (Implementation of the Montreal Convention 1999) Order 2002 [1][2].
The principal substantive provisions are:
Article 17 (Death and injury of passengers — damage to baggage): the carrier is liable for damage sustained in case of death or bodily injury of a passenger upon condition only that the accident which caused the death or injury took place on board the aircraft or in the course of any of the operations of embarking or disembarking. Cargo and baggage liability is addressed separately.
Article 18 (Damage to cargo): the carrier is liable for damage sustained in the event of the destruction or loss of, or damage to, cargo upon condition only that the event which caused the damage so sustained took place during the carriage by air.
Article 21 (Compensation in case of death or injury of passengers): for damages not exceeding 128,821 SDRs per passenger (revised effective 28 December 2024) the carrier shall not be able to exclude or limit its liability; for damages above this amount, the carrier shall not be liable if it proves that the damage was not due to its negligence or other wrongful act or omission, or was solely due to the negligence or other wrongful act or omission of a third party.
Article 22 (Limits of liability in relation to delay, baggage and cargo): liability for delay limited to 5,346 SDRs per passenger; baggage liability limited to 1,288 SDRs per passenger; cargo liability limited to 22 SDRs per kilogram. All limits subject to periodic revision.
Article 24 (Review of limits): the limits prescribed in Articles 21, 22 and 23 shall be reviewed by the depositary at five-yearly intervals and revised by reference to changes in inflation [4][6].
EU Regulation 785/2004 on insurance requirements for air carriers (as retained in UK law) sets minimum insurance limits by reference to the Montreal Convention strict-liability ceiling and the various other applicable limits [3].
A passenger purchasing a ticket for international carriage is accepting carriage on terms that incorporate the Montreal Convention (almost invariably by reference in the airline’s conditions of carriage). In the event of death or bodily injury, the passenger or their representatives can claim under Article 17 against the carrier without need to prove negligence, up to the Article 21 strict-liability ceiling. Above the ceiling, the carrier has a defence if it can prove absence of negligence or that the damage was solely caused by a third party [4][6].
The Convention imposes a two-year limitation period for actions (Article 35), measured from the date of arrival at the destination (or the date the aircraft ought to have arrived, or the date on which the carriage stopped). The limitation is treated as a condition of the right to bring the action rather than as a procedural bar that can be waived. The 2018 UK Supreme Court decision in Stott v Thomas Cook Tour Operators Ltd [2014] UKSC 15 illustrates the exclusive nature of the Convention regime: claims for non-Convention heads of damage (such as discrimination) arising out of international carriage are pre-empted by the Convention if they fall within Article 17 [7].
Insurance industry practice has aligned closely with the Convention regime. Combined single limit liability policies respond to whatever the carrier’s actual legal liability is under the Convention, with reserving and claims handling protocols designed for the strict-liability ceiling and the unlimited-above-ceiling structure. Major airlines maintain liability cover well above the per-passenger ceiling multiplied by typical aircraft seating capacity, reflecting the unlimited tail exposure for proven-negligence cases [4][5].
The Convention coexists with the older Warsaw Convention 1929 regime and its various protocols, which continue to apply between state parties of Warsaw that have not yet ratified Montreal. The applicable regime depends on the carriage in question; for carriage between two Montreal states (or a single Montreal state in ‘round-trip’ carriage), Montreal applies; for carriage between a Montreal state and a Warsaw-only state, Warsaw applies.
The Convention applies only to ‘international’ carriage as defined in Article 1. Carriage that is entirely domestic to a single state (a UK domestic flight, for example) falls outside the Convention and is governed by domestic law — in the UK, the Carriage by Air Acts (Application of Provisions) Order 2004 applies a modified Convention regime to domestic carriage.
Carriers that perform the carriage as ‘actual carriers’ under code-share or wet-lease arrangements remain liable under the Convention as ‘contracting carriers’, with allocation of liability between the parties governed by their commercial arrangements rather than the Convention itself.
The Montreal Convention’s strict liability and unlimited-above-ceiling structure has been highly influential beyond air carriage. Successive maritime liability conventions (notably the Athens Convention 1974 as amended by the 2002 Protocol, governing passenger carriage by sea) adopt a structurally similar approach.
A UK resident purchases a return air ticket from London to New York with a Montreal Convention state-party airline. On the return flight, the passenger suffers a serious back injury during severe turbulence that the carrier subsequently is unable to prove was outside its control. The passenger claims £600,000 in damages comprising medical expenses, lost earnings, ongoing care and pain and suffering. Up to the Article 21 ceiling (128,821 SDRs, approximately £130,000 at illustrative SDR rates), the carrier is liable on a strict basis without need for proof of negligence. The balance of £470,000 is recoverable subject to the absence-of-negligence defence; in the example, the carrier is unable to discharge the burden and the full claim is paid by the carrier’s combined single limit liability insurer. Figures in this example are illustrative.
This entry is part of the Apex Insurance Wiki. Last reviewed by Matt Bartlett on 2026-06-05. Next review: 2026-12-05.
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