Originally Posted by
galaxy flyer
Renard
I believe the APR thrust increase will be an increment above the derate, not to the full APR without the derate selected. If that is not the case, performance must be based on Vmcg and Vmca, if applicable, for the full thrust. In any case, those speeds must be calculated on the APR thrust.
In fact, the APR probably only add an increment above any reduced power set, if the throttles are left alone.
GF
From memory, APR (or ATTCS to use the FAA term) works EITHER way depending on the type. Sometimes its a delta to the current set thrust, and that's typical for a mechanically controlled engine; I believe other cases, which are some (but I can't say all) FADECs will actually go to a rated single engine thrust, rather than a delta to the current all-engines set. (assuming flexing is being done)
If there is a derate - as opposed to a flex - then there will likely be an APR set corresponding to each derate, for the reasons you mentioned.