Seven years since the program was launched, Boeing’s newest, state-of-the-art airliner, featuring cutting-edge technology such as folding wingtips and the biggest turbine engine in the world, the Boeing 777X, finally embarked on its maiden flight, taking off for the first time on January 25, 2020. 

The first of four dedicated 777X-9 flight test aircraft, the WH001, took off from Paine Field (PAE) in Everett, Washington, United States. After a three hour, 51-minute flight over Washington state, it successfully landed at Seattle's Boeing Field.

Over the coming months, the test aircraft would be used in a series of tests both on the ground and in the air.  But prior to the resumption of testing, which is expected “in the coming days” according to the manufacturer, the aircraft would first undergo checks. 

Previously, the airliner was expected to have it’s first go for the skies in the middle of 2019, around the time of the Paris Air Show (June 17-23, 2019). However, problems in the development of the massive GE9X engine, purpose-designed for the new jet, pushed the schedule by several months. 

The engines were finally installed on the aircraft in December 2019. Boeing’s new wide-body airliner left the paint shop and was moved for primary flight control system testing on January 7, 2020. 

"Our Boeing team has taken the most successful twin-aisle jet of all time and made it even more efficient, more capable and more comfortable for all," said Stan Deal, president and CEO of Boeing Commercial Airplanes. "Today's safe first flight of the 777X is a tribute to the years of hard work and dedication from our teammates, our suppliers and our community partners in Washington state and across the globe."

What is all the fuss about? 

The Boeing 777X, which includes the 777-8 and 777-9 variants, is a successor to the manufacturer’s previous Triple Seven aircraft models. Once it debuts, the newest Triple Seven will be the largest plane Boeing ever built, powered by the biggest turbine engine in the world. The 777-9 variant is also going to be the first twin-engine jet to be able to carry more than 400 passengers. 

With a truly impressive 235 ft, 5 inches (71.8 m) extended wingspan (both 777-9 and 777-8 versions), the 777X is the first commercial aircraft to feature folding wing technology. The aircraft’s tips can be folded up to decrease the wingspan to  212 ft, 8 inches (64.8 m) when the aircraft is on the ground, thus allowing it to fit onto taxiways and into regular gates. Extended, the larger wingspan increases lift capacity and allows to maximize fuel efficiency, according to Boeing.

As no similar technology exists on a commercial aircraft, the Federal Aviation Administration (FAA) had to create airworthiness conditions from scratch. However, while folding wing technology is a novelty for commercial passenger aircraft, it already exists on military planes operating from aircraft carriers, such as the Boeing F/A-18E/F Super Hornet. 

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 airliner. The engine is developed on the foundations of the GE90, which powers the earlier versions of Boeing 777. 

Launched in 2013, the GE9X engine will be the most fuel-efficient jet engine the company has ever produced on a per-pounds-of-thrust basis, according to GE. When it enters service with the 777X, power plant, which is roughly the size of a 737's fuselage, will be the largest commercial jet engine available.

The 777-9, which is the one that has just entered flight testing /entered the flight testing on January 25, is the larger of the two versions, seating up to 426 passengers in a typical two-class configuration. Its range is 7,285 nautical miles (13,500 km). Meanwhile, the smaller 777-8, could seat up to 384 passengers but has a longer range of 8,730 nautical miles (16,170 km). 

Boeing expects to deliver the first 777X in 2021.