These are transformational times for the aerospace connections industry – the people who make connectors, interconnects, wiring, cables and everything else associated with integrating aircraft systems. Trends such as alternative propulsion systems, the never-ending pressure to build aircraft equipment that is smaller and lighter, and increasing data throughput demands for avionics and other onboard systems are confronting this industry with new and unique challenges.
The Alternative Propulsion Trend
The development of eVTOLs (electric Vertical Take-Off and Landing) helicopters and other electrically-powered aircraft is captivating the aerospace connections industry.
“Propulsion electrification within aviation is a really exciting trend,” said Jim Carothers, product manager with W. L. Gore & Associates, an aerospace wire and cable manufacturer whose products are being used in NASA’s Perseverance Rover on Mars. “But it’s not only propulsion that is going electric: Capabilities that are historically associated with hydraulics and mechanics are transitioning to electric sources. This is driving a need for a whole new wave of interconnects to be able to support those capabilities.”
“There’s obviously a big push to truly electric aircraft,” agreed Jeff Behlendorf, director of Product Management with Carlisle Interconnect Technologies (CarlisleIT), a manufacturer of high-performance cables (including fiber optics) and wire. “This includes cabling and products that can handle much higher voltages, which is a technical challenge at high altitudes and low pressures. We have to deal with corona effects and arc tracking in that environment that don’t necessarily occur on the ground.”
Corona effects and arc tracking are just two of the issues affecting electric aircraft that have to be dealt with. The safe management of high voltage connections between storage batteries and aircraft engines is another challenge to be tackled. So is the impact that these high voltage pathways may have on aircraft low voltage systems while aloft.
That’s not all. “We have to consider options such as using plated copper versus aluminum due to weight considerations,” said Robert Moore, global specialist and principal engineer with TE Connectivity, a designer/builder of connectivity and sensor products for harsh environments. “We also have to think about the insulation systems for these high voltage wires at the temperatures and altitudes planned for eVTOL flight.”
“As well, we have to make sure that we are using materials that meet the stringent requirements of smoke toxicity and flammability for the aerospace market,” Moore added. “We can’t use the same materials that one would find in an automobile or in a house, because something goes wrong in an aircraft, it has to be able to descend from altitude safely in response, and the passengers/crew have to be able to see where the exits are when it lands.”
“Really, the biggest challenge is dealing with high voltage,” concluded Michael Traskos. He is president and CEO of Lectromec, a company focussed on the assessment and certification of aircraft wiring systems. “This requirement is being driven by ‘Green initiatives’ aimed at reducing aircraft pollution by going electric. It is certainly the biggest trend affecting the aerospace connections industry today.”
Smaller, Lighter, Tougher
The restricted space within airframes, plus the fact that every extra ounce of equipment cuts payload capacity and uses more fuel, is why connections manufacturers have always been under pressure to cut the size and weight of their products. Meanwhile, the fact that aircraft environments encompass wide ranges of temperatures and air pressures means that connections equipment has to be rugged and durable as well.
“We’re always working on reducing ‘SWaP’, which stands for Size, Weight and Power,” said Matt McAlonis, an engineering fellow (Aerospace) with TE Connectivity. “After all, if you consider a ‘hot’ market like space, it costs about $10,000 per pound to launch something.”
Granted, the per pound cost is lower in atmospheric flight, but it is still enough to motivate companies like TE Connectivity to investigate new and better ways to reduce SWaP. This why the company is exploring ‘Generative Design’, where a proposed piece of connective equipment is ‘SWaP-optimized’ using 3D modelling software before manufacturing ever occurs.
“We call these scanned items ‘organic shapes’,” McAlonis said. “Sometimes those organic shapes have to be 3D-printed, because they’re so different than the traditional shapes produced using machines.”
There are other ways available to reduce SWaP. Consider the case of Compulink Cable Assemblies (a division of kSARIA), a build-to-print contract manufacturer specializing in cable assembly and harnesses for the military environment. According to Brian Mahoney, the company’s vice president Marketing, “we have seen an increase in our military customer base incorporating molded strain reliefs into their tactical applications. This is because molded strain reliefs can often reduce cost, size, and provide for better environmental sealing over traditional offerings.”
Overall, “the connections industry is moving towards higher density, smaller footprints offering space and weight savings,” Mahoney observed. “In addition, we are starting to see end users position towards custom-manufactured cables to better meet their next higher assembly application requirements and to reduce size, weight and to improve manufacturability.”
Balancing Swap and Safety
The quest to reduce SWaP is the connections industry’s Holy Grail. “If you can have a nice full light wiring system, then it’s a huge win,” said Traskos. “Yet at the same time, light wiring can run counter to what’s necessary to ensure a safe wiring system. For instance, high voltage electrical systems need to have thicker insulation to prevent any sort of degradation during those long-term full-power exposures – even though this adds weight.”
At W. L. Gore & Associates, the goal is to hit all these marks without compromise. “We can help those systems reduce SWaP by delivering interconnections that are very small and very flexible, in temperature and environmentally resistant packages,” Carothers said.
Nevertheless, the need to provide aircraft with redundant critical systems limits how much SWaP can be imposed on them – and vice versa. “With redundancy comes extra weight,” said McAlonis. “And if you try to supply triple redundancy in a critical system, you end up with a diminishing return: You may be safe, but now you’re too heavy to fly your mission. As a result, you have to be willing to take calculated risks in order to balance reduced SWaP with a degree of redundancy. That’s just the reality of the situation.”
The Trend for More Data Throughput
Today’s aircraft have become ‘flying data farms’ with substantial amounts of information flowing between their digitally-controlled components. Add the need to share this data with ground-based Flight Operations, and the demand for high data throughout is on the rise. This demand is only heightened when one factors in onboard broadband communications for crew and passengers alike.
Responding to the trend for more data throughput is a top priority for connections manufacturers. As a result, “you’ll see companies like CarlisleIT spending a lot of time on advanced connectivity solutions that are focussed on getting more data around and on-and-off the airplane,” said Behlendorf. “Supporting broadband communications with Flight Operations and on behalf of the crew/passengers requires higher speed backbones onboard that use 10-100 Gbps data lines.”
High data demands are common on the newest aircraft in service, but they are also turning up on older models as owners bring them up to modern standards. “These data-driven systems help pilots and their crews make better-informed decisions while in flight,” Carothers said. This is why connections that can support high data throughput are becoming a must for aircraft of all ages.
Copper and Fiber Optics
Traditionally, connections manufacturers have provisioned data carriage using copper wires. However, the large capacity demands of modern integrated aircraft are convincing many manufacturers to move to fiber optic cabling systems. Basically, they are applying ground-based fiber optic designs that support multi-gigabit IP networks to fulfill similar needs in the air.
“We are seeing a trend in both military and commercial aerospace where OEMs are migrating away from heavy copper cables used in data communication applications and replacing them with light weight fiber optic solutions,” said Paul Jortberg. He is executive vice president of Business Development at kSARIA, a designer/manufacturer/integrator of aerospace fiber optic and electrical interconnect solutions.
This migration is being driven by Next Gen radar technology and other bandwidth-intensive applications, Jortberg explained. “We are also seeing a shift to high density fiber optic connectors in aerospace applications and a shift to fiber optic flex circuits in a wide variety of backplane applications,” he said. “Fiber Optic Flex Circuits provide for high density routing of fiber optic channels on a flexible substrate for backplanes and systems that require high density optical interconnects.”
Jortberg’s distinction about fiber optics being used for bandwidth-intensive applications is noteworthy, because different aircraft have different levels of data throughput requirements. This is why there is still room for copper in some onboard environments, and why connections manufacturers are maintaining capabilities in both technologies.
At CarlisleIT, “whether we select copper or fiber depends on what the customer needs,” said Behlendorf. “Either way, we’re supporting them with very high-density interconnect solutions that allow people to push that data around the aircraft.”
The Connectors Companies Mentioned in This Article
Carlisle Interconnect Technologies (www.carlisleit.com)
Known as ‘CarlisleIT’, Carlisle Interconnect Technologies designs, builds, tests, certifies and delivers interconnect solutions for customers in the Aerospace, Military, Space, Test and Measurement, Industrial and Medical Technology markets.
According to the company, the following products are aimed at the aerospace connections market:
Tufflite Aluminum-TLA: This is an extremely light and flexible power feeder option that feature aluminum conductors, with weight reductions up to 60 percent compared to other options.
Octax 10 Gbps Ethernet Interconnect System: Available in multiple form factors, these connectors are designed for reliable performance and termination in extreme, rugged environments.
Gigabit-10HP: These Ethernet cables (in Bonded-Pairs and X-Web) ensure reliable 10 Gigabit performance up to 500 MHz at distances of up to 90 meters in the most extreme routing, applications, and environments.
LITEflight Fiber Optic Cable: These cables are specifically designed to provide maximum performance and durability in the demanding conditions found in aerospace, military, industrial, and other harsh environments.
Compulink Cable Accessories (compulink.com)
Compulink Cable Assemblies is a build-to-print contract manufacturer that focuses on cable assembly and harnesses for military clients. The company’s connections product line includes coax, RF, MIL-C-38999 and custom molded cable assemblies for virtually any application.
Compulink has been providing cable and harness assemblies to the medical, transportation and military marketplaces since 1984. They are used in aerospace in-flight applications, plus military communications and computing, medical mannequins, and mine detection equipment.
kSARIA is a designer, manufacturer and installation services provider of mission critical fiber optic and electrical interconnect solutions for the defense and aerospace industries
kSARIA has recently introduced the OptiFLEX line of Fiber Optic Flex Circuits that provide high density routing of fiber optic channels on flexible substrates, for backplanes and systems that require high density optical interconnects. The company’s Fiber Optic Flex Circuits provide a manageable method of routing fiber from interface to interface.
Whether using individual Single mode or Multimode fibers, kSARIA’s computer-aided systems can manufacture the circuits in any routing matrix, size or shape. The company continues to enhance its product line by offering substrates with different materials, which are optimized for customers applications.
Lectromec is a laboratory and engineering firm that provides full life cycle support for wire system component testing and system engineering. The company works with aerospace companies, foreign and domestic militaries, and governments to address their electrical wiring interconnect system (EWIS) testing and risk assessment needs. Lectromec’s services include lab testing to assess component performance, EWIS certification support, and risk assessment of both new and aged platforms.
In line with the move to electric aircraft propulsion, Lectromec can now test aircraft connection systems and components with high-frequency high-voltage power, including measurements up to 5kV (kilovolts) and 4kHz to determine the long-term voltage endurance of EWIS components.
TE Connectivity (www.te.com)
TE Connectivity provides electronic interconnect solutions for the commercial and military aerospace industry from the initial stages of aircraft design to aftermarket support. The company offers component design to customers as well as low cost, turn-key finished assemblies.
They employ sophisticated computer modelling of the magnetic, thermal, mechanical and electrical parameters of a design to ensure optimum performance.
Among the company’s aerospace connections products are the following:
Single Pair Ethernet (SPE) Cable: This is a Raychem Single Pair Ethernet (SPE) cable, which provides faster data rates in a smaller, lighter solution. The SPE cable is designed to be durable and versatile to operate in harsh environments applications such as commercial and military aerospace, defense, electric vertical takeoff and landing (eVTOL) aircraft, and space.
MULTIGIG Connector: The MULTIGIG RT 3 is TE Connectivity’s fastest rugged backplane connector. It supports speeds of 32+Gb/s, making them among the fastest rugged backplane connectors for embedded computing or VPX systems currently on the market.
COPALUM Lite Sealed Terminals and Splices: TE Connectivity’s new COPALUM Lite sealed terminals and splices offers up to 60 percent in weight savings versus copper terminal alternatives.
Times Microwave Systems (www.timesmicrowave.com)
Times Microwave Systems designs and manufactures high performance coaxial cables, connectors and cable assemblies for aerospace, military, telecommunications, industrial RF and microwave applications. Their products include high-performance flexible, semiflexible and rigid coaxial cable assemblies, connectors and delay lines for applications requiring phase stability, phase tracking and the lowest possible attenuation at microwave frequencies in the most hostile environments.
Some of Times’ more innovative products include Zero dB cable assemblies that exhibit no loss by utilization of a miniature amplifier built into the assembly, blind mate antenna systems, and silicon dioxide (SiO2) cable assemblies. Commercial wireless products for telecommunications applications include flexible 50 Ohm LMR® cables, connectors and assemblies as well as SilverLine® test cables and Times-Protect® RF surge and lightning protection products.
W. L. Gore & Associates (www.gore.com)
W. L. Gore & Associates is an aerospace wire and cable manufacturer. It uses proprietary technologies based on the polymer polytetrafluoroethylene (PTFE) to create products for aerospace cabling, medical implants; fabric laminates; and cable, filtration, sealant, membrane, venting and fiber technologies for a wide range of industries.
Everyone is Seeking Solutions
Addressing the trends listed above is Top Priority for connections manufacturers and their customers in aircraft production, maintenance/upgrades, and ownership/operations.
According to Carrie Obedzinski, Business Development manager at Times Microwave Systems, it is their customers who are demanding solutions to a range of connections-related issues. “They’re trying to drive costs out of their business,” she said. “They’re looking to improve production efficiencies. At the same time, they want to reduce their inventories while speeding up their operations. For instance, repair facilities often only have overnights to do equipment replacements, which is why they want connections solutions that are fast and efficient to install.”
At Times Microwave Systems, their big challenge is to produce connections solutions that specifically address customers’ needs. “This is why we have a team that’s dedicated to actually calling on these customers and trying to gather that information from the customers as to what they’re really looking for and defining those parameters,” Obedzinski said. “We listen to their input to determine how do we can make our products better and package them as complete solutions that can be assembled quickly in the field.”
Over at Carlisle Interconnect Technologies, the company is developing new connection architectures to carry the high voltages demanded by electric propulsion systems. This is no easy task: “The truth is a lot of these advanced constructions are new to us,” said Behlendorf. “So we are struggling with newer insulation technologies to provide electrical isolation for these high voltage products from other low voltage systems within the aircraft.” Arcing is a particular problem with carbon composite aircraft, which don’t provide the degree of electrical isolation that aluminum airframes do. Without proper isolation, high voltage lines can end up arcing with the carbon composite airframe.
As always, reducing SWaP remains paramount. “There’s a lot of push to carry the power without adding pounds to the plane,” he said. “That’s driving us to explore alternate materials and metals for the conductors themselves. As a result, a lot of multilayer-plated conductors are being incorporated into products today. We’re also looking at new jacketing materials to control the arcing and maintain isolation of those high voltage systems, again without adding a ton of pounds onto the plane.”
Fortunately, there is a way for the aerospace connections industry to gain insight into solving high voltage issues, namely by looking at how other industries have learned to move high voltage electricity in a safe and consistent fashion. “The electrical utility industry has been dealing with tens to hundreds of thousands of volts safely for an extended period of time,” said Traskos. “So there’s a lot that can be learned from them in this regard. We need to find out how they have solved these problems, using the kinds of materials that work best in an aircraft environment.”
An Ever-Changing Marketplace
The trends influencing aerospace connections manufacturers are keeping them in a state of constant change. There is no time to rest on their laurels: Aerospace customers need connections technology that works with electric propulsion; moves data easily; resists high voltage; and is smaller, lighter, and tougher than ever before.
Looking ahead, it seems likely that the pace of progress will only increase, as OEMs advance into new propulsion systems such as hydrogen, develop autonomous/self-flying aircraft, and continue to incorporate novel materials that are lighter and stronger than aluminum into their products.
That the aerospace connections industry will find creative ways to address these changes is unquestioned. It is the specific ways in which they will do this, that remain to be seen.