CFM56-3, -5A & -5B maintenance cost analysis, Issue 8 Nov/Dec 1999

There are more than 6,000 CFM56-3s and -5A/Bs in operation. Despite
several teething problems, their durability has contributed to efficient
operating economics of modern narrowbodies. Re-rating to lower thrust is
allowing many operators to achieve the lowest possible shop visit and life
limited part replacement costs.