When passengers board an aircraft and see that there is in-flight entertainment and connectivity (IFEC) available, they just expect it to work, with little to no knowledge of the countless number of wiring, cabling, and interconnect components necessary to connect their mobile device with a website or stream a movie to their setback screen.
While the number of new orders, deliveries, and retrofit activity among the major commercial aircraft original equipment manufacturers hit historic lows over the last year, wiring, cabling, and interconnect component suppliers are still finding ways to introduce innovations that enable speedier data transmissions. The slowdown on the commercial end of the OEM spectrum has also caused some to turn to other segments of the industry, such as business aviation and defense or military aircraft.
“It is important to note that the commercial aerospace industry has been hit significantly hard due to the ongoing global pandemic,” Jeremy Moore, product manager for the aerospace fiber optics division of W.L. Gore & Associates told Avionics International. “This has stalled, indefinitely, research and projects that have been technology-focused in the industry. This created a pivot by many towards the defense industry, which due to their inherent long budget allocations have been able to continue to drive program and system upgrades with new technology, including fiber optic upgrades.”
In recent years, Gore has been one of the most diverse wire and cable suppliers in the aerospace industry. This was especially evident in February when the company highlighted the use of its cables to enable data processing and communications for the Mars Perseverance Rover’s entry, descent, and landing phase.
Back on Earth, a key focus for Gore is continuing to educate the commercial and defense sides of the aerospace industry on the benefits of using fiber optics to reach various aircraft system bandwidth and performance needs. Moore said the company is seeing higher demand for the use of fiber optics to support military aircraft applications, but that the “aircraft OEM manufacturing lines are slowly coming online, as are the industry standard committees, which push new wire and cable technology as well as define their specifications.”
“Fiber has historically been used more commonly in the commercial aircraft world for systems such as IFE data trunks, radar systems, 4K cockpit displays, and in some instances, there has even been fiber run directly to the seats for IFE displays. Fiber optic glass is inherently more fragile than a copper core, so it can sometimes come with a stigma about being used on aircraft, especially in harsh environments, or tough routing installations,” Moore said.
A growing number of radar systems and sensor applications are continually pushing the performance of fiber optics for military aircraft, according to Moore. However, there are new developments coming on the commercial side as well, primarily through the work of the Airlines Electronic Engineering Committee (AEEC) Fiber Optics Subcommittee.
“We are also seeing an industry need for fiber optics in satellite communication systems using RF over fiber, which is currently being defined and specified for industry use in the ARINC Fiber Optic Subcommittee meetings. This would help system performance with aircraft connectivity speeds and overall bandwidth as users drive the needs for more data, faster speeds, and lower latency. Gore is currently offering OM5 technology, which is the highest bandwidth offering fiberglass can support, in our ruggedized, small form factor packing,” Moore said.
Another AEEC sub-group, the Cabin Systems Subcommittee (CSS), is finalizing the ARINC 854 Cabin Equipment Network bus specification that will enable the use of Single Pair Ethernet in commercial aircraft cabins. The specification will shift traditional Ethernet wire and cabling configurations in aircraft cabins and throughout the aircraft from 8 and 4-pair solutions to 2-pair.
Robert Moore, principal engineer for the high-speed aerospace division of TE Connectivity, told Avionics that his company is a part of the committee and has been instrumental in reviewing standards that have been established for the automotive market and how those can adjust to aerospace applications.
“Ethernet, 100BaseT, 1000BaseT, and 10000BaseT are being used in IFE systems today,” Moore says. “So the inclusion of single-pair Ethernet is only new in how leads to the simplicity of ‘connectorizing’ a single pair of wires rather than say 2 pairs of a quadraxial cable into the defined size 8 contact of 4 pairs.”
Moore also provided an example of how Ethernet cabling used in other applications has shown the IFEC segment of aerospace how 100BaseT—a twisted-pair copper wire enabling 100 Mbps data transmission—has traditionally been supported with 4 pair cables when in reality the data flowing through them is only transmitted and received by 2 of the 4 pairs within the cable.
That allowed chipsets to automatically configure which pairs to use if there was damage to a pair or if there was too much signal degradation on the default pairs used, Moore said.
“The IFE industry used the knowledge that for 100BaseT implementation that only two pairs were required, focused on the use of 2-pair constructions in a quadriaxial configuration as the smallest/lightest configuration to package the pairs. Some implementations of 1000BaseT use two quadriaxial cables rather than traditional 4 pairs under a common shield and jacket. So the use of single-pair Ethernet is not amplification of Ethernet on aircraft but simplification of installation,” Moore says.
TE’s Mini-ETH Single Pair Ethernet interconnection system was developed last year to comply with the new ARINC 854 standard for 100Base-T1. However, the components are being provisioned to achieve 1 Gbps data rates, which is an ultimate goal for the 854 standard. The weight reduction offered by the use of Single Pair Ethernet could be significant, especially in some of the legacy wide-body aircraft that some airlines are still flying and could resume once international passenger demand for air travel returns.
TE’s white paper, Advancing Aircraft Connectivity with a Single Pair Ethernet Solution, outlines how the ever-increasing number of screens, sensors, data hubs, switches, solid-state drives, IFE servers, and other electronics need solutions that can accommodate their data transfers while using less wiring.
"Excess weight significantly affects fuel performance. For example, consider a Boeing B747-400 wide-body aircraft flying a 5,000 nautical-mile average stage length for 3,000 flight hours per year. Carrying the weight of wiring and connectors (1,814 kg/4,000 lbs) consumes nearly 60,000 gallons of jet fuel every year. The annual cost for that amount of fuel comes to nearly $115,800,” according to the white paper.
Current and next-generation aircraft connectivity air to ground and satellite networks, and their enabling wire and cable components will continue to drive demand for new solutions from suppliers as well.
As an example, in January, Florida-based wire and cable supplier CarlisleIT obtained a new supplemental type certification (STC) for the installation of the Honeywell Aerospace JetWave Ka-band system. Jeff Behlendorf, Director of Product Management, Integrated Products for CarlisleIT told Avionics how the STC process requires detailed electric wiring interconnect system (EWIS) assessment and identification of the aircraft zones where the new wiring is introduced.
“CarlisleIT has installed this particular STC configuration on 32 aircraft already. These installations were accomplished using the baseline FAA STC ST04334CH. Obtaining the EASA companion STC extends this modification to be available for European operators as well. This installation package includes the complete SATCOM system wiring harness and interfacing connections to the aircraft systems and equipment. That includes hookup wire, ethernet cable, low-loss coaxial cables, and all of the related connectors required,” Behlendorf said.
Retrofitting business jets with new connectivity was a steady source of demand for CarlisleIT’s wire and cable components over the last year, as commercial air travel plummeted to historic lows.
“Business aviation connectivity has been one place where retrofit demand really didn’t slow much in 2020. CarlisleIT has continued to see steady demand for both components and pre-wired subsystems for installing upgraded connectivity. We also continue to see strong and growing demand for enhanced cabin entertainment options directly at the aircraft OEMs. That includes a need for more fiber optic cables for cameras and Wi-Fi access points, 4K HDMI for large, high resolution 4K monitors, and even USB 3.1 cabling,” Behlendorf said.
The use of fiber optics is starting to become more common in business jet cabins as well, according to Behlendorf. Installing or retrofitting business jets can be more challenging, especially finding space for new equipment and cabling.
Some of the most basic properties of fiber, being more compacted and lighter weight than copper, makes it ideal for those tighter spaces.
“Using fiber not only allows you to get great data rates, but it also fits into very tight spaces, and there are no concerns of EMI conflicts with parallel wiring or systems. That allows installers to route it almost anywhere. There is also more comfort with aviation-grade fiber today. Systems designers are now more likely to use fiber in their equipment designs, and MROs are more skilled at maintaining fiber-based systems,” Behlendorf said.
PIC Wire & Cable parent company Angelus Corporation also turned its attention to the wire and cabling needs of the business aviation market over the last year. Tony First, senior technical sales engineer for The Angelus Corporation, told Avionics that his company is seeing growing interest for HDMI and USB interconnect solutions in business jet cabins recently.
“We have an HDMI product and are working on a USB C release for aircraft applications. We have witnessed a need for these items in the Corporate Aviation Market,” Forst said. “Ku and X Bands users like corporate aircraft OEMs utilize our Micromates cable line. These bands cover frequencies up to 26 GHz. Some of the avionics systems included in this category include the T-310 and Jetwave Systems.”
Over the next few years, TE Connectivity’s Moore believes that the wire and cabling trends for aircraft systems will follow what’s happening outside of aviation, in the world of consumer electronics.
“I see the data rates on aircraft following the trends that are going on in the commercial world,” Moore said. “I think the industry has shown that for data above a given rate, fiber optics is the preferred media for transmission.”