Originally Posted by
keenster
Just trying to figure things out. As Scambo says we should be flying Cost index and air speed on a transpac and that was what we were getting. But then yesterday we got the constant .85 mach with no changes in cost index. Funny thing is we plugged in ECON(the old way we used to fly) and is gave an arrival time of 3 minutes earlier. Next time will call the dispatcher to see what the reason is. Probably trying to make up time.
Delta is using the cost index and flight plans speeds to protect A+0 and A+14 if able when running late. If not then you often go back to econ even though you will be even later. The decision to go back to econ is made based on passengers connections and rebooking options. Lots of things as pilots we don't have information on. In one case we questioned a cost index of 555 on the 7ER that had us arriving 1 hour early and doing .835 to 84 most of the trip. Turned out they had two broken jets in ATL and really needed the aircraft for a SA trip.