The 737 MAX isn't the only plane Boeing is having trouble with right now. This was to be the year when Boeing rolled out its newest jewel, the 777X.  

It did leave the hangar, but few outside of the company noticed.  

At Everett's Paine Field there are two 777X planes on the Boeing flight line that are heading nowhere — for now.

The 777X is still in development. It's an advanced jet with the world's biggest composite wings made of carbon fiber instead of aluminum. It has a folding wingtip and the world's largest engines. 

The first flight is running up to six months behind. 

Governor Jay Inslee and the legislature fought to keep this major airliner program from going to another state. However, the 777X has virtually disappeared off the public's radar. It's been overshadowed by the serious safety problems of the 737 MAX jets. 

Boeing never committed to a date for the first 777X flight. There was a growing consensus among at least one of the airlines buying the planes that it would be the end of June. 

A key issue pushing back the inaugural flight is the GE-9X engines. 

Greg Smith, Boeing's Chief Financial Officer and Vice President for Performance and Strategy, said this about the GE engines: "There are some challenges. They're working through their own testing. We still expect to fly this year."

The engines are tested in two places: on the ground in Peebles, Ohio, and in the air aboard a 747 set up as a flying test bed. 

The 777X is a jet meant to haul a lot of people over very long distances. Reliability is everything. It appears that's where this issue rests in assuring that even under maximum stress for hours, nothing can break. 

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