Airplane 4 is carrying out what Boeing calls “right at first flight" test work, which involves turning the aircraft as a line operator would in normal daily operations.

The 737 MAX cockpit looks very similar to the 737NG, but new features include four 15.1 in LCD multifunction screens and new data collection and storage capabilities.
A focus for the investigations into the 737 MAX accidents is the aircraft's Manoeuvring Characteristics Augmentation System, a flight control law designed to enhance pitch stability.

N8702L is used for performance testing. It is pictured departing El Alto International Airport in La Paz during the aircraft’s deployment there for high-altitude take-off tests.

The larger fan size of the MAX 8’s CFM LEAP-1B engines relative to the CFM56-7BS on the 737NG is evident in this photo. The LEAP-1 B’s fan diameter is 69.4in (1,760mm).

The Advanced Technology Winglet is set to provide a 1.8% reduction in fuel burn compared to the Blended Winglets that feature on the 737NG.