Another good rule is not to climb 2000 ft unless you are going to be up there for at least 1 hour otherwise the fuel you burn getting up there will exceed the saving.
This would normally apply towards the end of a flight.
Forty years ago, when ATC conditions permitted, we used to use a climb - cruise technique. In other words, we never stopped climbing until we reached optimum as weight reduced or else it was time to come down again.
From the ATC point of view, we were given a block clearance of 2000 ft or so. In other words, the space between F250 and F270 was ours.
This would not of course be possible nowadays but it was a very efficient way of operating.
Last edited by JW411; 12th Nov 2004 at 16:38.