BAE Systems is advancing plans to provide lightweight fly-by-wire (FBW) flight controls for several eVTOL aircraft already under development. The goal is to produce a common baseline FBW package that can be easily adapted for multiple aircraft designs and be ready for test flights to begin by the end of 2021.
The aerospace and defense group has extensive experience in developing FBW controls, having introduced the technology for the F-16 and F-18 fighter aircraft in the 1970s. More recently, it has provided systems for commercial aircraft, such as Boeing’s 777 airliner, Bell’s 525 Relentless helicopter, and Leonardo’s AW609 tiltrotor.
In 2017, BAE started discussions with a number of undisclosed eVTOL developers that it considered had the best prospects for getting aircraft to market to assess their various requirements. The group’s flight controls engineering team at Endicott, New York, then started working on an FBW package to incorporate a propulsion controller, actuation controller, and a flight control computer.
The platform assembled so far can already host software developed by its prospective partners, allowing them to define the flight control laws for their aircraft and also to work on how redundancy will be managed. As this technology is matured, the BAE team will start to deliver engineering development units to companies that would be close to the versions needed for type certification, and which could be used on iron bird ground test systems.
According to Brian Hull, engineering director for strategic development with BAE’s electronic systems division, the company will spend the rest of 2020 assembling hardware and software for the common flight control computer. It expects this to be ready to begin environmental tests by late this year or in early 2021.
Hull told AIN that BAE wants to be able to have its FBW systems certified as early as possible to support the type certification timelines being pursued by the eVTOL developers it is looking to support. “Particularly with actuation and propulsion controls, we have to be able to show that a single point of failure cannot cause a catastrophic event,” he explained. “The certification agencies have given guidance on this and this has helped us to focus on how we can put a system together that will detect failures and mitigate them.”
Reducing the size and weight of the flight control systems is a critical goal for BAE in the eVTOL sector. This means balancing these factors against the need to still have sufficiently robust structures for the equipment, which has led BAE to look at using new materials such as advanced plastics.
“We could see early on that fly-by-wire would be a key enabler for urban air mobility (UAM),” Hull said. “With so many unconventional aircraft designs, strange architectures, and distributed power, it was clear that mechanical flight controls would not work.”
Another consideration, especially in the UAM sector, which is expected to see dense air traffic and less experienced pilots, is the potential for FBW flight controls to enhance safety by introducing a degree of automation. BAE is already doing some work on requirements for fully autonomous flight, but, in Hull’s view, this will take more time to mature and is more likely to be pioneered outside the realm of UAM air taxi services in cargo-carrying and military applications.
“The scalability that UAM is trying to achieve will require new thinking and technology, but it all has to be seen through the lens of practicality and safety,” Hull concluded.
Meanwhile, BAE Systems also is working to reduce the size and weight of its energy management and engine controls technology to be used with propulsion systems for new hybrid-electric and electric aircraft. The company has already produced equipment that is 40 percent smaller and lighter than units now in service on much larger turbofans while claiming that they will deliver 10 times the processing power. Jaunt Air Mobility is one of the eVTOL developers with which it is partnered.