A fast reply
mcdhu, on the way to Metric QFE land
I do not recall making an earlier post along those lines, but here's my fast (not completely thought out) reply.
I don't see the Increased Speeds / Improved climb as being any more dangerous in comparison to V2min.
In comparing V2min Vs Increased Speeds / Improved climb,
FOR A GIVEN WEIGHT / MASS, V2min will offer improved vertical clearance of 'colse in' 1st Segment obstacles, but degraded vertical clearance of further out 2nd Segment obstacles. Increased Speeds / Improved climb will be the reverse.
That's for a constant Weight, depending upon the location of the most critical obstacle (close in / further out) and if optimising the Speed schedule, the RTOW max may be at V2min, Increased speeds, or somewhere in between.
In pre-EFB times on the B777 and using paper Airport Analysis, many Takeoffs offered improved RTOW at the Improved Climb schedule, whereas there was no data at all for Improved Climb if 2nd Segment limited. The OPT in the EFB calculates the Optimum speed schedule for the actual obstacle array
That's the fast answer, probably a few points not well covered, later notes may be needed to fill in the picture.
Mutt also number crunches the B777, and will hopefully come in with a better explanation than mine.
Both methods are safe, depending on the obstacle array, one may be safer than the other on a given day, but both will meet the obstacle clearance criteria satisfactorily.
Regards,
Old Smokey