Because Asiana Flight 214 was international, lawsuits against the responsible airline are governed by the Montreal Convention. The Montreal Convention strictly limits where a passenger may bring suit. To bring suit against an airline in a U.S. court, the injured passenger must be a U.S. resident, the passenger’s ticket must have been issued in the US, or the trip must have had a final destination in the US. As discussed here, that means that many of the tourists who were victims of Flight 214 may not qualify to sue Asiana in the US.
The Montreal Convention also permits victims to sue the responsible airline in the country in which the airline’s principal place of business is located. In this case, that doesn’t help the victims because Asiana Airlines’ principal place of business is in Korea.
But some foreign passengers may have purchased their tickets through Asiana’s code-share partner, United Airlines. The Montreal Convention allows a passenger to sue not just the “actual carrier” (Asiana), but also the “contracting” carrier (the code share partner who issued the ticket). For some passengers, the "contracting carrier" may have been United Airlines. United Airlines’ place of business is in the U.S. That means that passengers who purchased a ticket from United may sue in the U.S. regardless of whether they qualify to sue Asiana here.