Boeing CEO Dennis A. Muilenburg says that controversy surrounding cooperation between Boeing and the Federal Aviation Administration (FAA) in aircraft certification, brought to light by the 737 MAX crisis, is unlikely to “significantly alter” the upcoming certification process of another Boeing debut ‒ the 777X.

The previous timeline of starting flight-testing the 777X in 2019 and entry to service in 2020 still stands in place. Muilenburg says the controversy surrounding 737 MAX certification is unlikely to affect certification of the new widebody. “I don't see anything there right now that would significantly alter the timeline for the 777X, but it's possible we could see something that would alter the content of the test program or how we go about certification”.

While now less public than prior MAX crisis, the 777X development program is making “good steady progress”, Boeing CEO has revealed during the Sanford C Bernstein Strategic Decisions Conference  on May 29, 2019. The first two flight test aircraft undergoing integrated system testing on the ground and the following two prototypes are in the final assembly. Testing also continues on the GE9X engine.

“The other pacing item for us is with GE on the engine and we're continuing to work through engine testing and those two timelines will come together for flight testing later this year and then we still expect to achieve entry into service in 2020,” said Muilenburg.

GE Aviation, an operating unit of General Electric (GE), is building the GE9X exclusively for the latest version of Boeing’s long-haul wide-body 777 airliners. The engine is much awaited by aviation enthusiasts for the sheer size of it. When it enters into service with the 777X, the GE9X, roughly the size of a 737's fuselage, will be the largest commercial jet engine available, according to GE. For instance, the power plant will have a composite fan case measuring at over 11 feet (approx. 3.40 meters) in diameter and (only 16) fourth generation carbon fiber composite fan blades - making it also the largest front fan of a commercial jet engine.

A successor of aging Boeing 777-200LR and 777-300ER models, the 777X is regarded as a competitor to the Airbus A350XWB family and, sometimes, even the A380. The aircraft is to come in two versions: the first model introduced is going to be the 777-9, followed by 777-8. The 777-9 can seat 400 to 425 passengers in a standard configuration and offer a range of 7,600 nautical miles (14,075 km).