"BA pilots have the right to fly any aircraft that was ever part of the BA fleet" That is
not what is being said. Nobody is refering to a/c which were
once owned by BA. OS is a wholey [?] owned subsidiary which will be flying BA owned a/c.
2 quotes from schedule K - our agreement with BA.
"The intent of this agreement is to promote employment security and
career opportunities for Flight Crew on the British Airways Master
Seniority List (BA Mainline Flight Crew). This agreement seeks to
take account of the concerns that the Association has in respect of
employment security and career development whilst not impeding
the commercial development of British Airways plc."
" This is irrespective of whether operating under the mainline BA AOC or that
of any of it’s subsidiaries."
That is the intent to which BA signed agreement. BA has since fought hard to insist that the "intent" of agreements" supersedes any subsequent specific text.
So if BA own the a/c - which they do in OS, or are operating them under a subsidiaries AOC - which I believe they will be doing in OS - then the pilots should be on the MSL - that was BA's agreement & intent then and should be now.
There are some specific exemptions for a/c which are certified under 100 seats - but they are not relevant to OS.
I hope that sounds right, cos it is what BA agreed.