A320 Bank Angle Problem
Hi Everyone,
Just wondering if anyone can shed any light on this for me.
A SID from CFU (can't remember the SID name) from the southerly runway (can't remember the runway either!) requires a max bank angle of 15 degrees for a left turn that effectively brings you back overhead at a minimum altitude of about 3,000 feet or something like that. The SID plate shows a track to overhead being in the region of 12 or 14 miles. When the SID is loaded into the FMGS, it draws a tight circle for the turn with a track of maybe 4 or 5 miles to the overhead. On departure, the AP rolled all the way over to 30 degrees in an attempt to keep itself following this green track line, giving us a really tight turn which left us passing the height constraint at 1500 feet!
Question:
I can't begin to understand the logic of the FMGS in this case, but I am suprised that it did not limit itself to 15 degrees for a SID. Am I right in assuming that it was simply attempting to follow it's own green line which it drew earlier and that it will use any bank angle it can to achieve it (up to 30 degrees)
Also, if I'm right there are limits to the AP bank angle depending on the margin over V2 or VLS or something like that? Would this fact be helpful in any way to limit the bank angle used?
Finally, would HDG mode have resulted in the use of a different bank angle? Or is it simply a case of havingto hand fly this departure next time, ignoring the FD?
Any ideas would be very helpful!
Thanks!
CP