Northrop Grumman and the US Air Force (USAF) have begun ground taxiing evaluations on the secretive B-21 Raider stealth bomber.

A USAF official speaking on the condition of anonymity tells FlightGlobal Northrop is currently “conducting ground taxi activities” on the first example of the next-generation strategic bomber.


Source: Northrop Grumman

Northrop Grumman has begun taxi testing on the first B-21 stealth bomber in Palmdale, California, several months after the company powered up the next-generation aircraft for the first time

“Rigorous testing is a critical step in the B-21 flight test programme,” the official says.

Without addressing specific actions, the official says the B-21 will undergo extensive testing to evaluate systems, components and functionalities as part of the development process.

“This testing allows us to mitigate risks, optimise design and enhance operational effectiveness,” the official says.

Unverified photos claiming to show the B-21 taxiing were posted to social media site Reddit and later X on 25 October. If authentic, they offer the first glimpse at the Raider’s aft section, including twin low-signature exhaust ports, a clearer view of the aircraft’s main landing gear and the trailing edge of the flying-wing type.

Taxi testing is another major milestone for the B-21 programme. In July, Northrop said it successfully powered up the first B-21 earlier in 2023.

“We successfully powered on the first flight-test aircraft in the quarter,” Northrop chief executive Kathy Warden said during the company’s second-quarter earnings call.

Northrop released new photos of the B-21 in September, publicly showing the stealthy type outside the hangar and on the tarmac at the company’s development centre in Palmdale, California.

The company first unveiled the Raider in December 2022, flanked by high-ranking military officials including US secretary of defense Lloyd Austin.

“Even the most-significant air defence systems will struggle to detect the B-21 in the sky,” Austin said at the Palmdale ceremony.

B-21 overhead air intakes

Source: Northrop Grumman

Northrop unveiled the first B-21 in December 2022 at its fabrication facility in Palmdale, California

If all goes smoothly in ground testing, the B-21 could take flight before the end of 2023. However, programme officials with the USAF and Northrop have insisted the schedule of that milestone will be “event driven”, based on the results of technical assessments.

Any unexpected issues during ground testing could delay first flight until 2024.

Northrop is initially assembling six B-21 airframes, the company has said. The first flight aircraft will be a “production-representative” test model designated “T1”.

“The jet that’s going to fly this year, for all intents and purposes, is a production jet,” Northrop Grumman aeronautics president Tom Jones said in September at the annual Air Space Cyber conference near Washington DC. “It’s got all the coatings, it’s got the mission systems, it was built using factory processes.”

The USAF plans to buy at least 100 Raider bombers – substantially more than the 20 earlier-generation B-2 Spirit stealth bombers it purchased from Northrop.

The service aims for the B-21 fleet to reach initial operational capability before 2030, with the Raider fleet stationed at Ellsworth AFB in South Dakota.

The USAF plans to replace its 20 nuclear-capable B-2s and 43 Boeing B-1B conventional bombers with B-21s.

Its 72 Cold War-era Boeing B-52H heavy bombers will continue to serve; Boeing is now working on a project to re-engine and update those jets into a modernised variant called the B-52J.