Originally Posted by
puntosaurus
They weren't going to Blackrock, they were going to BLKMO in the FMC, as commanded by the loading of the APBSS (AProach to BlackSod South) approach. The commander called it BLKMO when she misidentified it. The earlier crew being based on the west of Ireland presumably knew that BLKMO was Blackrock and that is was a large island, and presumably stayed higher later.
Thanks. That makes much sense.