EV120:
SIBA means a segment of the monthly bid in which only a specific type of flying is typicaly included, i.e. Europe. SIBA pilots volunteer by senority to fly SIBA type lines in a three month increments. We used to have SIBA (South America) in the B-727, but we no longer have. Depending on equipment and location of flying, it can go very senior.
Ricky