Altitude planning, for one. The flight plan step climb versus the FMGC Optimum step are often hundreds of miles apart. And that's with the winds inserted.
Not inserting the winds is like using cruise control on a hilly road. The poor car is reacting to the small slice of its environment it is aware of, instead of planning for changes.
[Thread Hijack:] Which brings me to another irritation, this constant use of the computerized flight plan as though it were gospel. One pilot will fly fast and hard, then point to the FOB on arrival and declare "I saved XXXX lbs this leg", then the next pilot will fly the cost index, look at the FOB and declare "I saved YYYY lbs this leg." Both think they are heroes. As though bias in the flight planning software, variations in winds aloft, turbulence, direct routing, and ATC constraints don't exist on a leg to leg basis. As though all that matters is the Mach number in the little window. Delusional.
Last edited by Cardinal; 14th November 2009 at 00:33.