Boeing delivered the first 737NG powered by CFM56-7BE turbofans–a 737-800–to China Southern Airlines at Boeing Field in Seattle last week. The new engines, now standard on all new 737s, includes improvements to the high-pressure compressor, a new outlet-guide-vane diffuser, fewer high-pressure-turbine blades and an “optimized” low-pressure turbine.

The next phase of the 737NG program, scheduled to last into the third quarter, according to a Boeing spokesperson, involves incorporation of a shortened, exhaust nozzle and a lengthened, re-contoured plug to aid exhaust-flow efficiency.

Aerodynamic improvements already include refined control surfaces on the wings, a redesigned, wheel-well fairing and a re-shaped anti-collision light.

CFM, the 50/50 joint company of Snecma (Safran group) and GE, supplies the new engines as part of the 737 performance-improvement package that Boeing began testing in November 2010. Boeing, which expects the latest package of modifications to cut fuel burn by 2 percent by the end of next year, also plans to incorporate inlet/exhaust modulation into the design of the environmental control system, while data analysis continues to quantify the final benefit to customers.

Boeing claims that its ongoing efforts to improve the 737NG family have already resulted in an accumulated 5-percent gain in fuel efficiency since it delivered the first airplane in 1998.