Cost Index B757-300
 

Hello, I wonder if any guys out there flying the B757-300 would give me a ballpark cost index that is presently being used in their operation?

UK charter with wingtips fitted - low. Around 15. Gives MNs of around .76 :{

Ok, that's what we see as well, I have seen speeds below M.75 and can't for the life of me (and my limited aerodynamical knowledge gained decades ago) believe that it is really economical. The airplane burns the same amount pr.sector cruising at M.79-.80 but gaining a lot of time. :=

You can't say it burns the same amount per sector unless all the other variables are absolutely identical. CI0 versus M79 may only save 40kgs. But it counts. You can't measure that saving even if you assured all variables where the same. Fuel is becoming more and more valuable than time so, yes, you may save 10 minutes air frame time at a higher speed but if the airline gives you a low cost index, it means it, even if it's M76. Boeing made up the aircraft AND the perf figures!

Drive your car at 50 versus 70 next time and see the benefit. But I can't for the life of me think why!? I save 20 minutes at 70!?

30 in normal ops and 100 if OCC wants the bird home quick.
With CI 30 it starts getting interesting once you get hit by some chops with tailwind during cruise. MNo zero wind Fl340 about 77 tailwind min 75 headwind max 78ish. Add .01 for Fl360.
RB535-E4B