In case you missed it, GE Aviation’s Chief Test Pilot Jon Ohman and Systems Engineer Jay Gwinn joined the Boeing team live on Instagram earlier this month to discuss testing and installation of the world’s largest jet engine on the world’s largest twin-engine jet, Boeing’s 777X.

At GE Aviation’s Flight Test Operations in Victorville, the second round of flight testing for the massive GE9X is underway on GE Aviation’s 747 testbed as part of final preparations for engine certification.

Watch the live Q & A below with Boeing to understand what types of tests are performed on the GE9X, and also why Ohman and Gwinn might just have the coolest jobs in the world.

Boeing also recently released photos from Seattle of the first 777X test plane after installation of the first GE9X engine. The plane is scheduled for its maiden flight this year.

The 777X will be “the most-efficient twin-engine jet in the world, with 12 percent lower fuel consumption and 10 percent lower operating costs than the competition,” according to Boeing. It will come in two variants, the 777-8 and the 777-9.

At more than 11 feet in diameter, the #GE9X is as wide as the body of an entire Boeing 737. The engine has 16 fan blades made from advanced carbon-fiber composites, six different 3D-printed parts inside the engine, and components made from a light- and heat-resistant material called ceramic matrix composite. The ceramics can handle as much as 2,400 degrees Fahrenheit and allow GE engineers to increase the temperature inside the engine’s hot section.

Top and above: Boeing has released the first pictures of the world’s largest twin-engine jet, the 777X, equipped with the world’s largest jet engine, the GE9X. The plane is scheduled for its maiden flight in 2019. Images credit: Boeing.