Originally Posted by
FlightDetent
Denti, depends on how your iPad (or whatever app you're using) is configured. The label is modifiable by the administrator, ours currently reads <= 27%.
Answer: according to Airbus guidance, the limit when to apply alternative forward CG lo-speed performance corrections is 27% indicated CG. (reference available).
The logic is, as I understand it: The aircraft is flown-certified with 25% CG position as the differentiating value. In controlled condtions, loading-wise, that is.
Because in real life operating scenario, the calculated / indicated CG postion is only approximation of actual CG - true passanger weight distribution being the most variable factor - a conservative margin of 2% is normally added to the limiting value.
It is easy to understand that RTOW charts show 25% because that's how they are calculated, but to use them without a correction for forward CG, one needs LDS figure of 27 or more.
Correct. Sometimes reading the notes on the FCOM is worth the time.
Let's check PER-TOF-TOC-10-20 TAKE OFF CHART DESCRIPTION , Corrections due to Different Take Off Conditions and check the "note" field.