The Mechanics of Airline Liability: How the Montreal Convention Actually Determines Compensation for Delays, Damage, and Death

You are standing at the baggage carousel in Rome, watching the belt grind to a halt. Your suitcase, containing your carefully planned Mediterranean wardrobe, is nowhere to be seen. When you approach the airline's customer service desk, the representative hands you a meager overnight voucher and points to a dense contract of carriage that seems to absolve the carrier of any meaningful responsibility. It feels like a rigged game where the house always wins. But for international travelers, that contract is largely an illusion.[3]

A superseding global treaty—the Montreal Convention of 1999 (MC99)—actually dictates exactly what you are owed, and the airline has no power to lower that ceiling. Adopted by the International Civil Aviation Organization (ICAO), this landmark agreement replaced the antiquated Warsaw Convention of 1929, unifying the fragmented rules of international air carriage into a single, predictable framework.[4]

The true genius of the Montreal Convention lies in its currency. Rather than pegging liability limits to the US Dollar or the Euro, the treaty uses the Special Drawing Right (SDR)—a basket of major currencies maintained by the International Monetary Fund. This mechanism ensures that inflation and exchange rate volatility do not silently erode passenger rights over time.[1][5]

When it comes to baggage, the convention is remarkably clear. If your checked bag is lost, delayed, or damaged, the airline is held to a standard of strict liability up to a specific limit. In 2024, ICAO revised this limit upward to 1,350 SDRs, which translates to roughly $1,800 USD depending on daily exchange rates.[1][2]

This means you do not have to accept a $50 voucher for a ruined trip. You have the legal right to claim the actual value of your lost items and necessary replacement purchases up to that ceiling, provided you can produce receipts. The airline cannot enforce internal policies that cap compensation below the MC99 threshold.[3]

Flight delays operate under a different, often misunderstood mechanism. Unlike the European Union's EU261 regulation, which pays a flat punitive fee for the mere inconvenience of a delay, the Montreal Convention compensates for actual, quantifiable financial loss caused by the disruption, up to a generous limit of 5,750 SDRs.[1][5]

If a severe delay causes you to miss a prepaid, non-refundable cruise departure or forces you to book an emergency hotel room, MC99 covers those specific damages. You must prove the financial loss, but the airline cannot simply hide behind vague excuses if they failed to take all reasonable measures to prevent the delay.[5]

The most profound shift introduced by MC99, however, concerns bodily injury and death. The treaty fundamentally changed aviation law by introducing a two-tier liability system that heavily favors the passenger and their surviving family members.[4]

Under the first tier, the airline is held strictly liable up to a newly revised limit of 135,000 SDRs for injury or death, regardless of fault. The airline cannot contest this baseline compensation by claiming they did everything right; if the injury happened on board or during boarding, they must pay.[1][2]

The second tier allows for unlimited liability if the passenger's damages exceed that 135,000 SDR threshold. To avoid paying these larger sums, the burden of proof shifts entirely to the airline, which must prove in court that it was not negligent or that a third party was solely responsible.[4][5]

Despite these robust protections, the convention has strict boundaries. MC99 only covers "bodily injury" caused by an "accident." Decades of legal precedent have established that purely psychological trauma—such as the terror of severe turbulence—is not compensable under the treaty unless it is accompanied by a physical injury.[5]

Furthermore, the definition of an "accident" is highly specific. The courts define it as an unexpected or unusual event external to the passenger. A passenger developing deep vein thrombosis from sitting too long, or suffering a heart attack mid-flight, does not qualify as an accident under MC99.[5]

To successfully invoke these rights, passengers must navigate strict procedural deadlines. You must file a written complaint with the airline within 7 days for damaged baggage, and within 21 days for delayed baggage. Missing these narrow windows completely nullifies your right to claim compensation under the treaty.[3]

One of the most traveler-friendly provisions of MC99 is its jurisdictional flexibility. If you need to sue an airline, the treaty allows you to bring the case in your home country, provided the airline operates there, saving you the immense cost and complexity of suing a foreign carrier in their local courts.[4]

Ultimately, the Montreal Convention transforms the passenger-airline relationship from a David-and-Goliath struggle over fine print into a standardized, predictable legal framework. Knowing that this invisible safety net exists—and knowing how to pull its levers—is the modern traveler's most powerful upgrade.[3][6]