The Two Core Baggage Allowance Frameworks
Commercial aviation baggage policies are divided into two distinct regulatory systems: the Weight Concept and the Piece Concept. Both systems dictate passenger free baggage allowance, excess baggage rates, and how allowances are encoded on the Electronic Ticket document.
• Weight Concept: Governs baggage by total cumulative weight regardless of the number of individual bags (subject to safety limits per single item, generally 32 kg / 70 lb maximum for ramp handling). Common in domestic and regional travel across Europe, the Middle East, Africa, and Asia-Pacific. On the ticket document and GDS pricing display, it is displayed as a weight measure, such as `20K`, `30K`, or `40K` (where K represents kilograms).
• Piece Concept: Governs baggage based on a fixed quantity of individual baggage items, each subject to individual weight and linear dimension limits (typically 23 kg / 50 lb for standard economy and 158 cm / 62 in overall dimensions: length + width + height). Standard on all flights to, from, or within the Americas (United States, Canada, Latin America) and increasingly adopted worldwide. On the ticket document, it is indicated as `1P`, `2P`, `0P` (Nil / no checked baggage), or `0PC`.
Interline Journeys and IATA Resolution 302
When an itinerary involves multiple airlines operating separate legs on a single ticket (interline carriage), discrepancies between individual carrier baggage policies can create confusion at check-in. To establish a single, predictable standard, IATA introduced Resolution 302 (Baggage Provisions for Interline Itineraries).
Resolution 302 provides a four-step hierarchical logic to determine which airline's baggage rules (known as the Most Significant Carrier or MSC) apply to the entire journey or ticketed check-in portion:
• Step 1: If the baggage rules of all participating operating carriers are identical, that shared rule applies.
• Step 2: If the rules differ, apply the published baggage allowance rules of the carrier operating the first flight that crosses from one IATA Tariff Conference Area to another (Area 1: Americas; Area 2: Europe/Middle East/Africa; Area 3: Asia/Southwest Pacific).
• Step 3: If the journey does not cross between IATA Areas, apply the rules of the carrier operating the first flight that crosses from one IATA Sub-area to another (e.g., within Area 2, from Europe to Middle East).
• Step 4: If the journey is entirely within a single IATA Sub-area, apply the baggage allowance rules of the carrier operating the first international sector. For purely domestic interline itineraries, the first operating carrier's rules apply.
Regulatory Exceptions: US DOT and Canadian CTA Directives
National regulators enforce critical exceptions to IATA Resolution 302:
• United States Department of Transportation (US DOT Rule 14 CFR Part 399.87): For all itineraries where the ultimate ticket origin or destination is a point in the United States, the baggage allowances and fees of the marketing carrier operating the very first flight segment apply throughout the entire ticketed journey, in both directions.
• Canadian Transportation Agency (CTA): Enforces a similar directive where the marketing airline of the first sector dictates allowances and fees across the whole Canadian itinerary.
Reading Baggage Allowance in GDS and Electronic Tickets
In standard GDS booking screens and electronic ticket records (TWD/E-ticket displays), baggage allowances are encoded in the fare construction and coupon data:
• `NVB` / `NVA`: Not Valid Before / Not Valid After dates.
• `BAG / BAGGAGE`: Specifies `0P` / `NIL` (Hand-baggage only / Light fare), `1P` (One piece up to 23 kg), `2P` (Two pieces), or `30K` (30 Kilograms total weight).
• Ancillary baggage: If excess or additional baggage is purchased prior to departure, it is issued via an Electronic Miscellaneous Document (EMD-A) linked directly to the corresponding flight segment.
Key takeaways
• The Weight Concept (e.g., 20K, 30K) regulates total cumulative weight, whereas the Piece Concept (e.g., 0P, 1P, 2P) restricts the exact number and individual weight of bags.
• IATA Resolution 302 determines which operating airline acts as the Most Significant Carrier (MSC) on interline multi-carrier journeys.
• US DOT regulations override IATA Resolution 302 on US routes, applying the first marketing carrier's baggage rules to the entire itinerary.
• Travel agents must verify the baggage indicator on the PNR fare quote display prior to ticket issuance to prevent customer disputes regarding hand-baggage-only (Light) fare rules.