OK;
(a) Data is correct but bear in mind that I am taking it from the manual loadsheet specimen and it is not the best basis for manually plotting the c.g envelope.
(b) The target MAC for MTOW 79t will normally be around about mac 18%/38 index units,( I guess it varies according to loading on the day) my original query arose for this post because at certain airports the take off perf. computer would limit me to lets say 78t
due to runway length, assuming MAC of around 18%,I would then input MAC25% (theoretically move c.g. aft) and recalculate the data, and would normally find an extra 500 to 1000kgs.
RGDS FH