Boeing explains why its new plane has flat-bottomed engines

Despite constraints, Boeing opted not to raise the overall height of the aircraft due to potential structural changes and certification complexities. Instead, they extended nose landing gear slightly and adjusted engine placement. This allowed them to certify the MAX as a derivative of previous models, speeding up market entry amid competition from Airbus's A320neo.

According to Safran, a partner in CFM International, "the LEAP-1B provides 737 MAX operators with a 15% reduction in fuel consumption and carbon emissions compared to the previous generation engine." It also meets stringent noise standards while delivering lower NOx emissions.

However, changes in aerodynamic behavior necessitated additional systems like MCAS (Maneuvering Characteristics Augmentation System) to address altered flight characteristics during high-angle climbs. Faulty data activation led to two fatal crashes involving Lion Air Flight 610 and Ethiopian Airlines Flight 302. These incidents resulted in global grounding until software overhauls were completed.

Ultimately, modifying engine nacelles allowed integration of larger turbofans without extensive structural changes or re-certification complexity. Today, after overcoming initial setbacks, Boeing is set to certify final variants of this series.