And BTW, I always thought the gee requirements for the heavies was 3 gees, plus a standard addition until structural failure. The 2.5 gee number surprised me.
Gums,
The actual requirement is a complicated formula that depends on MTOW, but pretty well all civil airliners this equates to 2.5g as a 'limit' load with a factor of 1.5 to be applied for ultimate (breaking) load. i.e. 3.75*MTOW is the design condition. At less than MTOW of course one could pull more.