As revealed on Flyertalk, United Mileage Plus members booking business class transatlantic or transpacific award flights can only be booked in coach on Singapore connecting segments.
- S*MPI/STAR-AWARD RULES.R:
**NOTE: X/I/O IS NOT OFFERED ON ALL ROUTES.
FOR SQ BUSINESS CLASS AWARDS WITH CONNECTIONS/STOPOVERS
TO/FROM A TRANSOCEANIC FLIGHT BOOK *I* CLASS FOR TRANSOCEANIC
FLIGHT ACROSS THE ATLANTIC/PACIFIC AND *X* FOR ONWARD FLT
EXAMPLE – SQ BUSINESS CLASS AWARD LAXDPS
BOOK *I* LAX-SIN AND *X* SIN-DPS
SQ AWARDS THAT DO NOT INVOLVE A TRANSOCEANIC
SECTOR USE *I* FOR ALL SECTORS INCLUDING 2 CABIN AIRCRAFT
Lesson is that if you fly Singapore on a business award you’ll want your onward connection on another Star carrier in order to remain in business.