Boeing has made a series of design updates to the re-engined 737 Max to support performance requirements. The updates, announced April 11, involve the design of the aircraft’s aft body, engine installation and flight control system.

The 737 Max tailcone will be extended, and the section above the elevator “thickened” to improve steadiness of airflow, Boeing said. The new CFM International Leap-1B engines will be integrated with the wing in a way similar to the design of the Boeing 787 Dreamliner engine with its wing. A new engine pylon and strut and an eight-inch extension to the nose landing gear will maintain ground clearance similar to that of current 737s while accommodating the larger engine fan. The nose-gear door design is altered to fit the revision.

Boeing said the aircraft’s flight controls will include fly-by-wire, versus mechanical, spoilers as a weight-saving measure. The 737 Max will also have an electronic bleed-air system, enabling optimal use of the cabin pressurization and ice protection systems.

The airframer said it expects to optimize the design of the 737 Max by the middle of next year. It said a possible revision to the wingtips is also being tested to determine if that would further benefit performance. Boeing is telling airlines that the 737 Max will burn 10 to 12 percent less fuel than current equivalent single-aisle airliners when it enters service in 2017.