Boeing yesterday announced a series of planned improvements to its 737 line the company says will result in a 2-percent decrease in fuel burn and a marked upgrade in cabin comfort and utility.

Boeing estimates it will achieve half of the fuel burn improvement through drag-reducing changes to the airframe, while the other half comes from hardware changes to the airplane’s CFM56 turbofans. Aerodynamic improvements include refined wing control surfaces, a wheel-well fairing redesign, a re-shaped anti-collision light and an ECS inlet/exhaust modulation.

Propulsion improvements include a shortened exhaust nozzle and a re-contoured plug, along with a 9-percent reduction in the number of airfoils in a new version of the CFM56-7B, due to enter service in mid-2011. Up to a 4-percent reduction in maintenance costs, depending on thrust rating, will result from the improved airflow and cooler temperatures the engine changes will affect, according to CFM International.

The company plans to start ground testing the engine in September and begin flight testing at GE Aviation facilities in Victorville, Calif., early next year, in time for expected engine certification in July 2010. Flight testing on a Boeing 737 would start in October 2010, ahead of expected certification for that airplane in the second quarter of 2011. Once certified, the Evolution engine will carry the nameplate CFM56-7BE.

Separately, seven airlines have agreed to incorporate the new 737 interior starting in late 2010. FlyDubai, Continental Airlines, Norwegian Air Shuttle ASA, Malaysia Airlines, Tui Travel, Gol Airlines and Indonesia’s Lion Air have all committed to the new cabin, characterized by soft blue LCD lighting overhead, sculpted sidewalls and window reveals designed to draw passengers’ eyes to the airplane’s windows. The sidewall design also integrates the air vent in a way that will ease pre-flight security checks for maintenance staff.

The new interior design includes larger, pivoting overhead stowage bins that add to the openness of the cabin and allow for more roller-bag capacity. Finally, Boeing redesigned reading-light switches so passengers can find them more easily and avoid accidentally pressing the flight-attendant call button.