Join Date: Jan 2008
Location: NYC, NJ, Long Island
Programs: DL DM, 1.6MM, UA Silver, NEXUS, SkyClub & AdmiralsClub Lifetime, Bonvoy Titanium
Posts: 6,645
According to Flight Aware DL158 was just north of the Japanese island chain when they diverted. Going to NRT kept them overland for most of the route vs. an over water continuation.
ETOPS may require that they take the shortest over water route on the diversion.
Also, parts and maintenance will be easier to deal with at NRT which is a regular Delta 747 destination than ANC which is not.
The flight landed at NRT at 6:01PM JST.