Northrop Grumman has completed the loads calibration test of the first B-21 Raider stealth bomber aircraft for the US Air Force (USAF).

The loads calibration test is one of the three crucial tests during the ground testing phase of the aircraft, before its first flight. It focused on calibrating instrumentation and verifying the structural integrity of the aircraft.

According to the company, the test generated positive and consistent results.

As part of the test, the airframe of the B-21 was put under different levels of stress to ensure that the aircraft is ready to attain flight readiness.

Apart from loads calibration, the ground test phase includes powering up the aircraft, testing the subsystems and applying coating and paint to the aircraft.

Following the ground phase, the B-21 will undergo engine runs, low-speed and high-speed taxi tests and then take its first flight.

According to the information provided by Northrop Grumman during its first quarter (Q1) earning call and the USAF’s projection, the first B-21 will undertake its first flight next year.

The company is also planning to roll out the aircraft later this year.

Department of Air Force (DAF) Rapid Capabilities Office director and B-21 Raider programme executive officer Randy Walden said: “The B-21 test aircraft is the most production-representative aircraft, both structurally and in its mission systems, at this point in a programme, that I’ve observed in my career.”

In April, Northrop Grumman received $108m advance procurement funds to support the production of first batch of B-21 aircraft.

The company is currently working on six B-21 aircraft, which are under different stages of production and testing.

Northrop Grumman is now focusing on reducing the production risk, refining the building process, and maturing the test fleet ahead of first flight.