Originally Posted by
Miraz
Does anyone have enough insight into this to know if BA operated the flight at maximum practical CI to go after the record?
Since this is now in an area for us amateurs, and since I had to google to find out what CI is, I thought I might usefully share this:
In the majority of civil aviation flights, aircraft operators have to trade-off between the fuel consumed and time needed to fly a certain route. Aircraft equipped with Flight Management Systems (FMS) use a Cost Index (CI) parameter when optimising the flight profiles. The CI express the ratio between the cost of the fuel and the cost of the time [6]. Thus, a CI set to zero means that the cost of fuel is infinitely more important that the cost of the time and the aircraft will fly at the maximum range speed. On the other hand, the maximum value of the CI gives all the importance to the time, regardless of the needed fuel. In this case, the aircraft will fly at the maximum operating speed (VMO/MMO) with, in general, some safety margins. Airlines can reduce their operation cost by an efficient management of the CI settings among their scheduled flights. Actually, a CI value not only affects to the cruise airspeed but will determine the whole profile of the flight. This means that the optimal flight level may change and that t
From here
https://core.ac.uk/download/pdf/41758368.pdf