Quote:
For a B-777 that would mean final flaps of 25 instead of the usual 30.
Airport authorities worldwide, not just LHR or NRT might like a lot of things done certain ways but safety can mean non-compliance. The authorities at NRT may "require" operators to use Flap 25 but regardless of their wishes I can promise you Flap 30 does get used.
From Narita Jepp 20-4:
"
APPROACH (Delayed Flap and Reduced Flap Setting)
(b) Use, as the final landing flap setting, the minimum certificated landing flap setting published in the approved performance information in the Airplane Flight Manual for the applicable conditions."
There is no question that the PIC makes the final decision ref "for the applicable conditions".
Again, from Narita 20-4: "The final authority to apply these procedures, however, rests on each pilot-in-command, who may use other appropriate procedures if determined to be necessary in the interest of safety."