Rotorcraft manufacturer Bell continues to progress development work on the US Army’s next-generation tiltrotor, with delivery of the first prototype still expected in 2026.
Still known only as the Future Long-Range Assault Aircraft (FLRAA), the new craft aims to provide drastic improvements in speed and range versus the army’s current troop carrier – the Sikorsky UH-60 Black Hawk.
While those aerodynamic enhancements are a primary focus of the FLRAA programme, Bell is also highlighting another feature of its design: the ability of the aircraft to quickly incorporate future upgrades, at a reduced cost, when compared to existing platforms.
The Pentagon calls this concept the Modular Open Systems Approach (MOSA), and Bell is at the forefront of the push.
“I’ll use the word Pathfinder effort,” says Frank Lazzara, director of sales and strategy in Bell’s advanced vertical lift unit.
The army’s FLRAA acquisition is the first major development effort with MOSA at its core, although other Pentagon programmes are also expected to embrace the concept.
The aim of open systems is to reduce long-term costs by breaking so-called “vendor lock”, wherein a prime contractor retains an effective monopoly on future modernisations by designing proprietary intellectual property into the heart of a new aircraft.
Under the MOSA approach, government-owned hardware and software are built into the design, allowing third-party suppliers to develop new systems and capabilities that can, in theory, be incorporated into an aircraft much faster.
Thinking about future upgrades even before the first prototype is delivered represents a radically different approach to aircraft design, according to Lazzara. He notes Washington has previously focused primarily on performance, with a secondary emphasis on cost, ease of upgrades and sustainment.
“It’s never been done before,” Lazzara says.
With FLRAA, the army is giving equal weight to those life cycle considerations, including MOSA and the use of digital models to help improve the design and maintenance of each aircraft.
In addition to reducing costs, the Pentagon believes this approach will help address issues of obsolescence and mitigate any issues or shortcomings with a new system not detected until it reaches troops in the field.
With aircraft development timelines sometimes spanning multiple decades, the technology embedded in a new aircraft might already be out of date by the time it reaches frontline service.
Lockheed Martin’s F-35 stealth fighter has suffered from this phenomenon, with the Pentagon now spending billions of dollars to upgrade the jet’s single engine after advancements to sensor and communications technology quickly outpaced the aircraft’s onboard power and cooling capacity.
Lazzara, a former Bell-Boeing V-22 Osprey pilot in the US Air Force, notes his aircraft was also affected by the old procurement model of lengthy development timelines.
“By the time I got in a V-22 in 2005, that aircraft had been around for two decades in development,” he says.
The US Navy began developing the pioneering tiltrotor under the Joint Services Advanced Vertical Lift programme in 1982, after the range limitations of existing rotorcraft contributed to the failed 1980 attempt to rescue American hostages in Tehran following the Iranian revolution.
Although the V-22 did eventually deliver significant improvements to speed and range, the transforming aircraft did not enter service in significant numbers with the US Marine Corps until 2007.
“MOSA is the answer to that,” Lazzara says. “[That’s] why the army is putting so much emphasis on equal priority for MOSA.”
Even without the focus on ease of future upgrades, the first FLRAA tiltrotor appears set for delivery in substantially less time than its Osprey ancestor. Handover of an initial test aircraft and subsequent first flight are scheduled for 2026, just three years after Bell was confirmed as the contract winner in 2023.
In the meantime, the company is continuing to work with the army toward finalising a FLRAA design.
Before it assembles any of the new tiltrotors, Bell will provide the army with two “virtual prototypes” to help the service evaluate the design’s mechanical and aerodynamic performance, without needing to fabricate a costly flightworthy test aircraft.
Lazzara says the virtual prototypes, which are scheduled for delivery in February, look similar to flight simulators, but also include Bell’s full digital engineering model of FLRAA. That allows for a holistic assessment of the design, rather than just a simulation of flight handling.
Bell is also incorporating feedback from the US Army’s frontline aviators and ground troops, as part of the design process.
In September, the army’s aviation procurement office gave personnel from the Hawaii-based 25th Infantry Division the opportunity to conduct drills on a FLRAA mock-up, complete with mounted machine guns, a full-size troop cabin and a cockpit depicted via augmented reality goggles.
The army’s programme management office for the FLRAA acquisition tells FlightGlobal the input provided by soldiers will help shape the new tiltrotor’s final design.
The office says it is “still awaiting final data analysis and report from the special user engagement with the 25th Infantry Division in September. Once we receive the final report, we will review and provide recommendations for implementation.”
Elsewhere, Bell on 6 November announced it will be producing FLRAA fuselages in Wichita, Kansas, at an existing facility owned by parent company Textron.
Aerostructures manufacturer Spirit AeroSystems provided the fuselage on the Bell V-280 prototype that won the FLRAA selection competition. However, Bell confirmed in October that it had dropped Spirit as a supplier and would produce the fuselages internally.
Although no reason was offered, the move comes as defence competitor Boeing is working to re-acquire Spirit, which had been part of Boeing until being spun off in 2005. Spirit produces various aerostructures for Boeing jets, including 737 fuselages.
“We are committed to investing in advanced manufacturing to ensure we deliver exceptional performance at an affordable cost to our customer,” says Bell chief executive Lisa Atherton.
Taking responsibility for a key aircraft component gives Bell a greater degree of predictability in an aerospace market that is being rocked by a production stoppage at Boeing as it was only just beginning to stabilise after years of disruption from the Covid-19 pandemic.
“We want to be able to control the things we can control,” Lazzara says.
He notes Bell already oversees production of the FLRAA’s tiltrotor drive systems and other “flight safety critical” items. With the programme still in the early stages of development, the change to fuselage production is not expected to significantly impact the current timeline for delivering the first of the new aircraft.
“I think it is a good time for us for that to happen,” Lazzara notes. “It has given us the reaction time we needed to do to address this properly.”
While Bell is focused on the US Army as its primary FLRAA customer, unconfirmed reports suggest the company is also pitching the tiltrotor to other potential buyers, including a maritime version for the US Navy that could be used for anti-submarine warfare and a long-term successor to the US Coast Guard’s fleet of Sikorsky MH-60T Jayhawk search and rescue helicopters.
Bell confirms to FlightGlobal that it has had discussions with other military services about the capabilities offered by FLRAA but declines to provide specific details of those engagements.
However, at least two unique versions of the FLRAA design are known to be in the works, beyond the standard troop carrying configuration.
Lazzara confirms Bell has digital mock-ups of a FLRAA medical evacuation variant, which have been shown to the US Army’s surgeon general. These feature a patient handling system in the troop cabin designed to hold litters bearing wounded troops.
The army similarly has a medevac-configured variant of its current Sikorsky UH-60 Black Hawk troop carrier, internally designated the HH-60M.
US Special Operations Command (SOCOM) has also confirmed its plans to acquire the new tiltrotor for the US Army’s 160th Special Operations Aviation Regiment, which provides rotary-wing support to the Pentagon’s elite commando forces.
SOCOM operates a separate procurement system that works independently from those of the Pentagon’s main service components.
The 160th typically operates heavily-modified versions of standard US Army aircraft, including variants of the UH-60 and Boeing CH-47 Chinook. While in the past that has required significant structural and electrical changes to meet special operations mission requirements, alterations to the FLRAA design may be far less intensive.
SOCOM says it has been working with Bell and the army’s procurement office during the initial FLRAA design process to streamline the nascent tiltrotor for future special operations forces-oriented modifications.
Rotary-wing procurement officials at SOCOM have previously confirmed the final FLRAA design will incorporate features that allow it to be altered quickly and at minimal cost with special operations features like an air-to-air refuelling probe and nose-mounted terrain-following radar.
Other aircraft operated by the 160th have been modified to include an aerial refuelling probe, including the MG-47G Chinook derivative and MH-60M special operations Black Hawk.
At the US Army’s annual aviation conference in April, Brigadier General Scott Wilkinson, who was then the head of US Army Special Operations Aviation Command, said the FLRAA design will be easily compatible with the needs of special operations forces.
SOCOM has been working with the army to ensure the aircraft can be “rapidly configured for our use… with minimal modification to original airframe”, Wilkinson said at the time.
Acquisition documents revealed at the Special Operations Forces Week conference in May indicate SOCOM is expecting to field its first special operations-configured FLRAA in 2034, several years after the first conventional US Army unit is set receive the standard version of the tiltrotor in 2030.
Steven Smith, the head of rotary-wing procurement for SOCOM, said at the time that the army’s aviation procurement team will take the lead on the FLRAA acquisition, to include initial flight certification of the standard aircraft design.
