And why is QF not the MSC on this itinerary given it is the first carrier to travel across an IATA area (SYD-LAX) on this ticket?
See my previous post:
The ultimate ticketed destination is MAD which is outside of USA/Canada therefore the US/Canada baggage rules do not apply. This means that each journey will potentially have a different baggage allowance as each journey is assessed for who the most significant marketing carrier is.
---
In the event that the ultimate ticketed origin or destination is in the USA/Canada, then the US DoT/Canada CTA rules apply. When these rules apply, the first marketing carrier can elect one of the following:
1. Apply their own policy to the whole ticket
2. Defer to IATA resolution 302 for selection of the most significant marketing carrier across the entire ticket
This choice by each carrier, is filed with ATPCO.
Two examples that come to mind are QR tickets ex-Canada as QR allows both AC and WS on the Canadian domestic to connect to their long haul service out of YUL.
Example 1:
YYZ WS YUL QR DOH
WS elects to defer to the IATA resolution 302 for determination of the most significant marketing carrier, which is QR. QR policy then applies to the whole ticket.
Example 2:
YYZ AC YUL QR DOH
AC elects to apply their own policy. AC policy then applies to the whole ticket.
Furthermore, if the ultimate ticketed destination was indeed in the USA/Canada, and the ticket involves all three traffic conference areas, the first marketing carrier performing carriage across the atlantic is the most significant marketing carrier.