The B-21 Raider: A Bomber That Is Both Low Observable And Easier to Maintain

The B-21 will sport more durable low observable treatments and coatings—allowing the Air Force to test out Environment Protection Shelter Prototypes like the one pictured above at Ellsworth Air Force Base to house the bomber on the flight line.

Stealth aircraft have always had challenges related to maintainability due to the need for specialized personnel, equipment, materials, and facilities. That’s not the case with the B-21, and in this Q&A with Steve Sullivan, vice president, Strike Division, we discuss how Northrop Grumman has applied new innovations in supportability to the program.

Breaking Defense: Northrop Grumman has extensive experience in designing and maintaining low observable aircraft. What lessons learned is Northrop Grumman bringing to the B-21 to support sustainment?

Sullivan: The B-2 Spirit, which we designed and built in the 1980s, was revolutionary not only for the shape of the airframe but also the low observable (LO) treatments and coatings that were applied for survivability. These have set the standard for the last three decades.

Our advancements in LO were not without their challenges, however. At the time, the overwhelming focus of the build was the LO design; maintenance consequences of the design had not yet been fully realized. Early stealth aircraft have required extensive resources, including specialized personnel with unique training, and aircraft hangars and other facilities with narrow temperature and humidity requirements for both aircraft maintenance and storage of materials.

Today, with the B-21 Raider, our team has made maintainability an equally important requirement to stealth performance, and the results have been better than we could have hoped. Through the application of lessons learned on B-2 and other stealth aircraft, and the use of digital engineering techniques, not only do we have a design that has significantly improved over the B-2 from both a survivability and aero-performance perspective, we also now have a coating system that is as revolutionary in its maintainability as the original B-2 systems were in their stealth performance.

Furthermore, we’ve exceeded performance requirements.

Breaking Defense: How is Northrop Grumman using digital tools and software to deliver the Air Force a fleet of aircraft that turn quickly and stay in the field longer?

Sullivan: We’re working toward the goal of eliminating the typical, long maintenance requirements that modern military aircraft require between missions by building an aircraft that is ready to fly every day. Under the leadership of our CEO, Kathy Warden, Northrop Grumman continues to invest in digital tools, modeling and processes that have been instrumental in reducing our lifecycle maintenance footprint, which will greatly benefit our USAF operators and maintainers.

We have designed in maintainability and cost from the outset of the B-21’s development program. We closely monitored the maintenance performed on the B-2 and made sure we were identifying and addressing those items that were systemically causing maintenance actions across the fleet. You won’t see the need for similar actions for the B-21. At the same time, we accommodated the use of existing common support equipment during the design phase to save the cost of designing new equipment specific for the B-21.

Our experience with the B-2 also influenced our approach to the B-21’s coatings. Specifically, we learned on the B-2 that not every little scratch or missing patch of material affects the overall signature of the platform. As it turns out, the coatings are very resilient to minor imperfections; the challenge is understanding which imperfection is significant enough to need repair and how many in aggregate can be allowed before a maintenance action must be accomplished.

This is where digital tools we have developed become invaluable. These tools allow us to first measure and catalog any imperfections, which are then entered into a digital model to determine which, if any, negatively affect our signature and need to be repaired. This cuts down maintenance time between missions significantly, and allows the maintainers to concentrate on only the items that affect the ability of that aircraft to perform its next mission.

Breaking Defense: You mentioned that special facilities have historically been required to maintain and store LO platforms. How will these be different for B-21?

Sullivan: This improved maintainability is driven by both the resiliency of the build process and materials over the long term – a head start on maintenance itself – and the ease at which they can be repaired. All of this will result in a more maintainable, affordable and sustainable aircraft with lower-cost infrastructure.

Recently the Air Force released an image of one B-21 environmental protection shelter that the Air Force is testing at Ellsworth Air Force Base, and I was surprised it didn’t get more attention – not for what it is, but for what it’s not. It is a simple, low-cost shelter that’s really there to protect the maintainers who will work on the aircraft. That is a testament to the progress that government and industry have made together over the past three decades on the durability of LO materials.

Breaking Defense: Once fielded, keeping the B-21 and the Air Force a step ahead will be enabled by rapid software upgrades. How is Northrop Grumman incorporating rapid upgradeability into the design and work being done now by NG and the USAF software sustainment team?

Sullivan: We are committed to the Air Force’s DevStar approach, which, as we have previously discussed, is the ability to quickly upgrade or modify software to accommodate the ever-changing battlefield and operational needs of our platform. This isn’t just a promise that will take effect after we deliver the first B-21; we are developing our software today using both Open Mission System (OMS) and DevStar. This will be the natural progression as we move from the development phase into production, and finally post-delivery support.

Gen. Timothy Ray, the commander of Air Force Global Strike Command, recently stated the B-21 will not have block upgrades and will integrate new weapons and capabilities on the aircraft in significantly less time than current weapon systems. He and the U.S. Air Force have the confidence that the B-21 team will deliver on his prediction because of the credibility we earned through collaboration with the Department of the Air Force Rapid Capabilities Office, other USAF organizations and, most importantly, our end users. As a team, we enjoy unparalleled transparency to identify issues early and proactively apply resources to drive the best possible outcome for the program.

Additionally, Ms. Warden has challenged and empowered us to improve efficiency through cloud computing. We are leaning hard into developing cloud-native applications to foster collaboration across our teams. We’ve also kicked off an experiment to migrate portions of our ground system into the cloud—an industry best practice approach that maximizes the flexibility, resiliency and scalability for our operators and maintainers in the field. Both efforts are in the early stages, but we’ve already seen promising preliminary results.

Breaking Defense: How is Northrop Grumman partnering with the Air Force to prepare for the operation and maintenance of the B-21 Raider?

Sullivan: Our commitment to the operators and maintainers of the B-21 weapon system doesn’t just result in rapid upgrades to existing systems and the addition of new capabilities; we are also setting a new benchmark for maintainability as a result of collaboration between our own world-class product support team, as well as Air Force maintainers in the design process. Our product support team had approval authority on virtually every engineering drawing released during development. As a result, we were able to address their needs along with those from their Air Force counterparts. This results in an unprecedented, maintainable design.

We also implemented several digital transformation initiatives, including the stand-up of our Highly Immersive Virtual Environment, or HIVE. The HIVE allowed our engineers and maintainers to walk through a digital representation of the B-21 to ensure their designs would not only be producible during the manufacturing process, but would also identify items that could cause issues during maintenance so that they could be mitigated early in the design process. This has the potential to alleviate design changes, rework and other maintenance drivers in the field.

The team’s use of the HIVE has additionally spawned new uses for the technology used to develop it. We now also have augmented reality (AR) goggles on the manufacturing floor that our skilled technicians use to drive efficiency into the manufacturing process. No longer does a technician have to rely solely on drawings and planning instructions on how to build our B-21; they can simply put on AR goggles and see a complete aircraft that is rendered by the thousands of released engineering drawings that make up the build. Through the goggles, a technician can see exactly how the subsystems, brackets, electrical cables, hydraulic lines and other equipment are supposed to be installed before they even pick up a tool to do their work.

Breaking Defense: Is your team thinking about how these digital tools can support long-term maintenance?

Sullivan: Yes, if you take this technology and the applications we’ve found in manufacturing, just think of the possibilities in maintenance and sustainment.

Air Force maintainers could have the capability to see single or multiple layers of the aircraft when it’s in depot, so if they only want to see where all the hydraulic lines go, it’s as simple as downloading that file and walking out to the aircraft. If the maintainer is interested in understanding the separation requirements between those hydraulic lines and adjacent fuel lines or electrical harnesses, they can load those layers as well.

These innovations were once the thing of science fiction, but we’re applying them today in partnership with the Air Force. Our team is bringing the best industry has to offer in software development, manufacturing and sustainment. It is truly an exciting time to be in aerospace and on the B-21 program in particular.

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