But his argument is real. The reason fuel dumping system installation may be required is the OEI climb gradient. I have no knowledge or comment about the actual weight or limits on that night.
The debate will rage on regardless: Is such delay just getting ready for the missed, or lining up one's self for a failure on the remaining one? On an ETOPS maintained frame, ... da .. da ... Probably the most value is if we can learn something new from the other opinion's camp.
Meanwhile,
- does it make sense to ask the CC to prepare PAX for a possible evac - for a "simple" OEI but grossly overweight landing?
- is it prudent to delay the approach to for the above to finish, if the cockpit drills are done quicker?
I hear the cabin setup will take 8 - 13 minutes. (Limited) personal experience suggests the guidance to the above from the manuals is rather inconsistent across operators.
My choice: Cabin EVAC preparation only if it is foreseen. OEI overweight does not require that.