OPNLguy From , joined Dec 1969, posts, RR:
Reply 1, posted (14 years 6 days 17 hours ago) and read 980 times:
Haven't heard this, but if true, they're probably upgrading their CFM56-B22 engines to either a -B24 or -B26 rating for more performance and payload lift. From what I understand, it's essentially a re-calibration and re-setting of the existing engine controllers, along with some other minor modifications, along with $upporting paperwork/documentation (always big bucks).
They have about 190 of the -300s, and 25 -500s, so that 300-engine figure you mentioned equates to 150 aircraft. maybe they're only doing the 150 newest -300s and -500s in the fleet.