United’s Brand-New 787 Dreamliner That Was Sent Back to Boeing Because it Kept Breaking Has Been Grounded Just Days After Being ‘Fixed’

A brand-new United Airlines Boeing 787-9 Dreamliner featuring the Chicago-based carrier’s upgraded ‘Elevated’ interiors with new Polaris Business Class suites and Polaris Studios has been grounded yet again, just days after it was returned to United after undergoing maintenance work by Boeing.

The aircraft (registration: N61101) was only delivered to United fresh from the Boeing 787 Dreamliner assembly line in Charleston, South Carolina, in late February. Since then, however, the aircraft has been plagued with problems, leading to multiple flight cancellations and diversions.

The problems became so bad that in late June, it was revealed that United was sending the plane back to Boeing to undergo substantial maintenance work in an attempt to resolve the irritating teething problems that have plagued this particular jet.

On June 20, the aircraft was flown from its base at San Francisco International Airport (SFO) to Moses Lake, Washington State, a massive Boeing facility, which, until only recently, was known as Boeing’s ‘Shadow Factory,’ where unwanted planes were sent to be parked up for lengthy periods.

United has remained silent on the technical issues that have been afflicting this particular aircraft, although it has now been revealed that the problems are related to an emergency anti-collision system known as TCAS.

TCAS stands for ‘Traffic Alert and Collision Avoidance System,’ and it is often described by aviation experts as the “last defense against mid-air collisions.”

The system is able to detect nearby aircraft using antennas built into the aircraft and sounds an audible alarm in the cockpit if it detects the threat of a midair collision. It functions independently of ground-based alert systems, giving alerts when all other systems have failed.

The latest version of the system is known as TCAS II, providing both traffic advisories and resolution advisories. The latter, resolution advisories, is the most serious type of alert, and provides pilots with specific instructions to avoid an imminent midair collision.

TCAS is mandated on all commercial aircraft in the United States, and airlines can’t just continue to operate a plane if the system is not working.

After spending 10 days at Boeing’s engineering facility at Moses Lake, the aircraft was returned to United on June 30 and two days later, on July 2, it operated a domestic service from San Francisco to Houston and back without any issues.

Later that day, the aircraft returned to long-haul international service, operating a transatlantic flight from San Francisco to London Heathrow as flight UA-930. On July 3, the aircraft was scheduled to return to San Francisco as flight UA939, but the flight ended up being cancelled.

sooooo, I had received the info that the primary issue here was "Plagued by TCAS issues"– and not just this one. But I was reluctant to post it. (I did DM it do a couple folks at the time.)

Now, cat's out of the bag on that: https://t.co/Q3qqRjeIuj

"TCAS keeps failing. Both…

— JonNYC (@xJonNYC) July 3, 2026

In a message sent to passengers who had been set to take this flight, United said: “Your flight is canceled because we needed to take the plane out of service to address a maintenance issue. Your safety is our priority, and we’re sorry for the inconvenience.”

According to various sources, Boeing had tried to fix the TCAS issues plaguing this aircraft by replacing both of the antennas that feed data into the system. While not currently confirmed, it appears that this fix didn’t do the job.

United has now taken delivery of seven Boeing 787-9 Dreamliners with the new ‘Elevated’ interior, and while another new aircraft, with registration N61104, also appeared to be having some initial problems, the issues affecting this tail now seem to have been resolved.

Some teething issues should always be expected with the introduction of a new aircraft, especially when new cabin products (seats, entertainment, etc) have been introduced. However, the problems impacting N61101 seem to be a lot worse than what would ordinarily be anticipated.

N61101 represents a massive investment by United as it seeks to become America’s ‘Premium Airline.’ United Elevated is the airline’s project name for the introduction of new seats and aircraft that will set the carrier apart from rivals like Delta and American Airlines.

United’s new 787-9s feature 56 next-generation Polaris Business Class suites with sliding privacy doors, along with eight Polaris Studio seats, which are a brand new concept for United – essentially a ‘Business Class Plus’ product with larger seats, more legroom, and an upgraded service.

The premium heavy airplane also features 35 Premium Plus seats, and just 123 economy seats (39 of which are Economy Plus seats with extra legroom). The aircraft is the template for what United’s long-haul, widebody passenger experience will look like for years to come.

United Elevated also includes the introduction of new Airbus A321neo ‘Coastliner’ airplanes that will replace ageing aircraft that operate transcontinental flights between Los Angeles and New York, along with A321XLR planes that will serve thinner transatlantic routes.