I think the 'Minimum Speed' is it's Minimum 'Clean' Speed Vref30+80 on the B757 & 767. 'Maximum Speed' would be Mmo (Max. Mach Operating no.). Quite a mileage difference over 7 hours between M0.78 (e.g) & M0.86 (e.g)
Can any B777 Pilots on here suggested a Range/ Endrance improvement figure for flying at Cost Index 0 in ECON?