YVR gets 10 abreast because BR cannot increase frequency (restricted by air service agreement with Canada) - it can probably support 2x daily 9 abreast at least seasonally. This is also why YVR was the last 747-400 long haul destination... BR actually needed the capacity and large number of Y seats.
SEA gets 10 abreast presumably because 2x daily 9 abreast is too much seats - this is mostly O&D market for BR as it lacks UA feed.
SFO gets 2x 10 abreast presumably because 3x daily 9 abreast is too much seats.
I don't know the load factors on VIE but probably similar as SEA/SFO... multiple daily 9 abreast is too much seats so they go 4x weekly 10 abreast. I don't think BR has much onward feed business at VIE so it is focused on VIE-BKK O&D and TPE-VIE O&D.
Last edited by bzcat; May 30, 2017 at 7:39 pm