I believe the original plan was the 380 until they found out they couldn’t go polar with it as it doesn’t have enough fire suppression for the holds. Because of their age the 747 had a dispensation against this requirement. What is plan B? I don’t know. This question also applies to Haneda as Qantas think the 380 will go there however Asiana and Korean have been trying to get it in there for two years unsuccessfully , what’s plan B? No idea.