Flights & Travel · International

The 1999 Montreal Convention: Carrier Liability Limits, SDR Calculations, and Baggage Claims Protocol

One international treaty sets the baggage and delay liability limits for nearly every international flight on Earth — and one missed deadline can forfeit your entire legal claim, regardless of how strong your case is.

Legal Framework: A Unified Treaty, Not a Patchwork of National Rules

The Montreal Convention of 1999 (MC99) is a unified international treaty governing airline liability for passenger injury, flight delays, and baggage mishandling on international flights between the treaty's member states — currently around 140 countries. Before MC99, airline liability was a genuine patchwork of inconsistent national rules; the Convention replaced that with a single set of strict liability tiers expressed in Special Drawing Rights (SDRs), a reserve asset defined by the International Monetary Fund based on a basket of major world currencies rather than any single national currency.

Using an IMF-defined unit instead of dollars or euros directly means the Convention's real-currency value shifts slightly day to day with exchange rates, but the underlying SDR figure itself only changes when the treaty's built-in review mechanism updates it.

The Current Liability Limits (Updated December 2024)

Article 24 of the Convention requires these limits to be reviewed every five years to adjust for inflation. The most recent review took effect on 28 December 2024, raising the limits roughly 17.9% from the prior 2019 figures:

For a rough real-currency sense of scale, 1 SDR was valued at approximately US$1.33 in late 2024 — meaning the 1,519 SDR baggage cap translates to roughly US$2,000 depending on the exchange rate on the day your claim is assessed. These are caps on the airline's liability, not guaranteed payouts: you still need to prove your actual loss up to that ceiling.

The Strict Claims Protocol: Deadlines That Forfeit Your Claim

This is the part of MC99 that catches out the most travelers, because the deadlines are absolute — miss one, and you lose your legal cause of action against the carrier entirely, regardless of how clear-cut your case would otherwise have been.

Step 1: File a Property Irregularity Report (PIR) at the airport

Before leaving the arrivals hall, you must file a PIR with the ground handling agent. This is essential evidentiary proof that the incident occurred and was reported promptly — but it is not, by itself, the formal legal claim. It's the first step, not the last.

Step 2: Meet the specific written-claim deadline for your situation

The sequencing matters: filing the PIR starts your evidentiary record, but the 7-day or 21-day written claim deadline is what actually preserves your right to be paid. A traveler who files a PIR and then simply waits, assuming the airline will follow up, can lose their claim entirely by missing the written deadline — even though they did the first step correctly.

What This Means for Your Claim

Treat the PIR as step one of two, not the whole process. As soon as you have it, calendar the relevant deadline — 7 days for damage, 21 days for delay or loss — and send your written claim well before it expires, not on the last possible day. If you're building your case, our Lost Luggage Inventory Template helps you document the value of everything inside the bag before you submit, and our letter generator can draft the formal written claim itself, referencing the correct SDR cap and Montreal Convention article for your situation.

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