Boeing 777X Certification Process Continues With 10 Hour Test Flight

Boeing’s 777-9 test aircraft, registered N779XX, has been busy conducting test flights over the past few months. On March 30th, it performed the longest 777X flight to date, spending just over 10 hours in the air- six minutes longer than a September test flight. Let’s take a look at where the aircraft flew during this lengthy test.

Boeing 777X Certification Process Continues With 10 Hour Test Flight
The Boeing 777X photographed returning from its inaugural flight at Boeing Field in Seattle, Washington, on January 25, 2020. The new type has faced several delays and is now set to enter service in 2023. Photo: Getty Images

“This is part of our rigorous test program for the 777X, which is progressing well. We’re conducting a comprehensive series of tests and conditions, on the ground and in the air, to demonstrate the safety and reliability of the design.” – Boeing spokesperson

10 hours and four minutes

Spotted by our friends at, the 777-9 took off from Boeing Field (BFI) at 11:05 on March 30th. With a total flight duration of 10 hours and four minutes, the aircraft returned back to Boeing Field at 21:09 – a long day for the 777X’s development and testing team.

The aircraft was recorded reaching a top speed of 550 kt (1018km/h), climbing as high as FL410 (roughly 41,000 feet).

As you can see from the Twitter video embedded above, the 777-9 registered N779XX flew from Boeing Field south to Northern California. The plane turned around over the skies of Eureka and headed up as far north as the Flattery Rocks National Wildlife Refuge at the northernmost tip of Washington State.

This distance would certainly not take 10 hours. However, the jet turned around and headed south again to the same area in California, flying over towns such as Fortuna, Arcata, and McKinleyville.

In total, the 777-9 went “back and forth” a total of five times before concluding its test flight.

In late September, Boeing conducted a 777X flight of similar (but shorter) length with the same plane. The aircraft took off from Arizona, traveled across another 16 states, and then landed back again.

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Flying more than some A380s

With many commercial airlines’ Airbus A380s grounded amid the travel downturn, N779XX has been logging more flight hours than jets already cleared for commercial service.

In fact, notes that in February 2021 alone, the jet covered 11,465.8 NM with an average of 3.5 hours of flying per day. For the past 12 months, the aircraft has logged 119,141.5 NM over 333 flight hours and 173 separate flights. The aircraft appeared to be the busiest during August, September, and October of last year.

Boeing 777X Certification Process Continues With 10 Hour Test Flight
A pair of Boeing 777-9 jets sitting parked at Boeing Field in July 2020. Photo: Getty Images

Last month saw the aircraft take off on 28 test flights, operating almost every day. While there were a few days spent completely on the ground, Boeing made up for this by conducting multiple test flights on other days (March 18th and 22nd are good examples).

Where else has this test aircraft been flying?

While this particular test aircraft has mainly been flying out of Boeing Field and around the Puget Sound area, it has also flown further inland to Moses Lake, also in Washington State. Boeing also has testing facilities at this location.

Early March also saw the jet spend a week flying in and out of Yuma, Arizona. Boeing jets come here for hot-weather testing, among other things.

Are you tracking the 777X’s test flights and progress as Boeing continues to work on bringing the jet to market? Let us know in the comments.