Rockwell Collins is planning to deliver the final software load to Boeing for 737 MAX cockpit displays in mid-September, followed by initial deliveries of the final hardware components by year-end.

The handover will wrap up four years of design, development and test work made more challenging by Boeing's goal of maintaining maximum commonality between the 737NG and the 737 MAX, in part to retain common type ratings between the two and minimal "differences training" for pilots.

Boeing is targeting 2017 for first deliveries of the re-engined and otherwise modernized 737, for which it has garnered more than 3,200 firm orders.

"One of the things that has been a challenge for us and for Boeing is that we are taking a 2015 display system and sticking it on an airplane that was designed in 1964, and has not changed all that much in terms of hydraulics, electrical and air conditioning systems," Keith Stover, MAX program chief engineer for Rockwell Collins, said. "We were trying to shoehorn this new system into it and provide capabilities that do not exist on the current aircraft."