SINGAPORE February 24, 2004 Integration of the advanced CFM56-3 Time on Wing (TOW) upgrade kit into Southwest Airlines' 737 fleet is well underway, with the airline currently operating ~150 upgraded engines; Air China has upgraded one -3 engine.
CFM56 engines are produced by CFM International (CFM), a 50/50 joint company between Snecma Moteurs (Safran Group) and General Electric company of the United States.
Southwest launched the TOW package in 2001 with an order for 300 kits and is on track to have them all in service by 2006. Air China ordered five kits. More than 4,400 CFM56-3 engines have been produced for the Boeing 737-300/-400/-500 series, representing a tremendous long-term market potential for the engine upgrade package.
The TOW kit, which features advanced three-dimensional high-pressure compressor aerodynamics (3-D aero) and new high-pressure turbine hardware, was certified in mid-2002. The upgrade is installed during normal overhaul and provides significant benefits, including: a 1 percent improvement in specific fuel consumption, as well as up to 15 degrees additional exhaust gas temperature (EGT) margin, which reduces maintenance costs through longer on-wing life.
CFM56-3 engines average 16,000 hours on wing before requiring an initial shop visit, and about 10,000 hours after overhaul. The TOW core upgrade will improve post-overhaul time on wing by as much 1,500 to 2,000 cycles. Also, lower operating temperatures, coupled with material improvements, reduce operating costs.
Turbine improvements include new nozzle and shroud materials, a new blade coating, and improved cooling. These changes extend component life and lower scrap rates and repair costs by as much as 50 percent.