My best take: CREW OXY = OFF is the grain source of truth here.
but many marbles and glasses had been broken, lost, or left unpolished along the way.
Now, as the OP themselves would put it, OXY is
below the GPWS switches, as opposed to
in-line where LDG FLAP 3 is placed.
At the same time quoting verbatim again, the OXY illuminates white when de-pressed to
OFF, whereas LDG FLAP 3 shows
ON.
Originally Posted by
Dmxxx
Left hand overhead panel, under GPWS switches , always set LDG FLAP 3 Off!
EDIT: Upon a second read I understand that "under GPWS sw" in proper English means "within" and I failed to appreciate that.
Either way, it is foolish. Also, I don't press buttons by reading an "SOP Checklist", and I haven't seen anyone trained to do so. Except for one specific case with 'Securing the ACFT C/L' which many like to use in a read-and-do style (result only a little out of sequence) - the one with OXY = OFF - just saying.