Boeing spent most of 2011 evaluating two fan diameters of the CFM International Leap-1B engine : 66.1 in ( 168 cm ) or 68.1 in ( 173 cm ) , both of which would require few changes to the landing gear to maintain a 16.9 in ( 42.9 cm ) ground clearance beneath the engines .
Boeing spent a lot of 2011 looking at two different diameters of CFM International LEAP-1B engine : 66.1 in ( 168 cm ) or 68.1 in ( 173 cm ) .