It certainly wasn't 4g for a loop when I was taught aeros.
In Oz I thought a B747 is certified as a 'normal category' a/c, in which case the usual 'g' limits are +3 / -1.xx (can't remember exactly).
Different in different countries? Or certified under an exception to the rule?
Still might be possible since many a/c are constructed to withstand 50% above their certified load limits.