Most Significant Carrier

For customer journeys that involve more than one carrier, International Air Transport Association (IATA) Resolution 302 governs baggage allowances and charges, using a concept of the Most Significant Carrier (MSC) to determine whose baggage rules apply for the itinerary.

These rules are based on a checked baggage concept, which is from when a bag is checked in until it is picked up, as such there may be various carriers allowance and charges applied across a customer’s entire ticket. For tickets issued on or before 31 March 2015 under Resolution 302, the Operating Carrier is generally the MSC, especially when they are operated by a partner airline (code-share flights).

For tickets issued on or after 01 April 2015 under Resolution 302, the Marketing Carrier is generally the MSC, including for flights operated by a partner airline (code-share flights).

How is the Most Significant Carrier (MSC) determined?

There are a number of steps in determining which carrier is considered the MSC based on the 3 IATA areas and the sub areas within each of those areas and where travel takes place for the checked baggage journey.

The following IATA areas and Sub areas should be used with the examples below outlining the steps to determine which carrier’s allowances and excess charges apply.

  • Area 1: North America, Central and South America, Hawaii
    • USA, Canada, Mexico
    • Caribbean
    • Central America
    • South America
  • Area 2: Europe, Middle East
    • Europe
    • Middle East
    • Africa
  • Area 3: Asia, Guam, Southwest Pacific
    • Japan, Korea
    • Southeast Asia
    • South Asian Subcontinent
    • Southwest Pacific
Step 1

The first carrier crossing from one IATA Area to another.
Unless specified assume that the sectors shown are connecting flights and considered a single checked baggage journey.

Examples:

Example 1 - Carrier YY is the Most Significant Marketing Carrier.

IATA Area 3 to IATA Area 3

XX

IATA Area 3 to IATA Area 2

YY is the carrier crossing between IATA areas

Example 2 - Carrier YY is the Most Significant Marketing Carrier for the departing journey and carrier XX for the return journey.

Departing flights

Departing flights

IATA Area 3 to IATA Area 3

XX

IATA Area 3 to IATA Area 2

YY is the carrier crossing between IATA areas

Returning flights

Returning flights

IATA Area 2 to IATA Area 3

XX is the carrier crossing between IATA areas

IATA Area 3 to IATA Area 3

ZZ

Exception to step 1: when travel across Areas 1, 2 & 3 in this order only. In this instance the carrier that crosses between area 1 & 2 applies. Carrier XX is the Most Significant Marketing Carrier.

IATA Area 1 to IATA Area 2

XX is the carrier crossing between IATA areas 1 & 2

IATA Area 2 to IATA Area 3


YY

OR

Step 2

The first carrier crossing from one IATA Sub-area to another (applies when travel is within an IATA Area).

Example 1 - Carrier XX is the Most Significant Marketing Carrier.

Southwest Pacific to Southeast Asia

XX is the carrier crossing between IATA sub areas

Southeast Asia to Southeast Asia

YY

OR

Step 3

The first carrier flying an international sector (for travel within a Sub Area).

Example 1 - Carrier XX is the Most Significant Marketing Carrier.

XX is the carrier on the first international sector within the sub area

YY

Example 2 - Carrier YY is the Most Significant Marketing Carrier.

XX

YY is the carrier on the first international sector within the sub area