Old_smokey,
If you were just talking about the basic BFL charts in an operations manual I would agree with you that they do not account for obstacles, as they are not airport/runway specific.
However the Boeing software methodology reduces the takeoff weight for the obstacle and then provides a balanced field solution. This data is then presented as a limiting takeoff weight and the speeds can be obtained directly from the FMS.
All companies don’t use this method; I have another electronic AFM that even though the input selection is "balanced", obstacles will “unbalance” the output.
It is therefore imperititive that crews KNOW exactly what their ops engineers are trying to do, this can only be achieved through adequate training and company procedures.
Mutt.
SR71,
Still interested in knowing how you actually brief the takeoff procedure. Using the lower V1 of 135kts, with the knowledge that you can safely abort at 165 kts. Do you brief your PNF that your maximum abort speed is 135 or 165?
Mutt.