Why not just use the normal charts and deduct the penalty, why you MUST use the re-calculated set of tables instead (where the penalty condition is not clearly indicated even) ? <--> Is that your dilemma?
Hi FD. Ummm, not quite. I personally don't think the following statement:
"Takeoff and approach climb performance limiting weights are reduced by xxx kg" implies that we can simply add xxx kg to the actual weight in order to get the new takeoff performance. Some of my colleagues do. But then on the other hand, where is the explicit statement in the CDL that says alternative takeoff performance MUST be performed for this situation? The GEN section speaks about how takeoff performance can be calculated (by someone in the back office with the Octo software) but not that we as pilots must do it (the CDL is after all written for the pilot). CDL item 27-01 is clear about the fuel penalty, it gives precise numbers that make people think about fuel. However, there's no (at least no obvious) guidance on how we as pilots, late at night in the middle of nowhere, can determine the performance when the performance manager is in bed.
Appreciate your input. Maybe I'm thinking too hard about it.