Fruitbat Flyer.
Yes, the CFM 56 may be an expensive engine to overhaul but then again its probably the amongst the most reliable and cost effective engines in the world.
QF/AN and others have had the engines on the wing for excess of over 25,000 flying in some cases without a removal.
I loved flying the old JT8's, but they require alot more maintenance overall, are alot more finicky (especially the combustion chambers) and not nearly as reliable or efficient.
Airlines such as Qantas, Southwest and Virgin Blue have done extensive research and guess which engine comes out ahead?
Also, are Ozjet considering using BAe146's ?
For their sake I hope they pay the engineers alot of money for the time required to maintain those ALF502's - they really do need a heap of TLC compared with other engines.