The DC-9s were supposed to go to 2027, I have the chart. The -50s are nowhere near the 100,000 cycle limit. The problem is most guys are lazy and fly the jet too fast because there is no FMC controlling the autothrottles. This increases fuel burn. NWA should have re-engined the DC-9 (circa 2000) with the TAY or BMW engine, the payback timeframe was only 3 years, but thats too long a time frame for an airline to contemplate.