Originally Posted by
Steve M
If that's the case, then it's a misnomer that "SWU availability being limited on the 77W." That makes it sound like it's harder to use an SWU on a 77W for some reason particular to that aircraft, and/or that seats are being limited. Based on what you said, it's just more difficult to get the cleared in advance.
This is precisely the case for the 77W. A lot of people pay for J and wish to upgrade to F using their SWUs. There are only 8 F seats - and F can sell out w/paid pax, thus indeed it is specific to that particular aircraft.