Product Focus: Connectors

For aircraft manufacturers and operators it’s simple math: adding new technology, such as in-flight entertainment (IFE) systems, and subtracting weight yields an increase in service quality and lower fuel costs. However, this simple equation complicates the task of aerospace connector manufacturers who must deliver smaller, lighter products that can still meet the growing bandwidth and speed requirements of a market that remains very much in flux.

The industry imperative is to reduce size, weight and power consumption and increase bandwidth and speed, said Earle Olson, business development manager with Tyco Electronics, of Berwyn, Pa. “This is something that must be done, and involves everything from power panels all the way to a simple disconnect on the seat leg.”

The drive for higher throughput is being fueled by IFE and connectivity systems that now deliver mobile and Wi-Fi communications along with on-demand video. They require “connectors with higher frequency, higher speed rate, higher power,” said Jon Prouty, business development manager at Radiall, of Chandler, Ariz.

IFE systems, which require bulk rate date transfers, would benefit from connector and cabling designs that are optimized for 10 Gigabit Ethernet, said Larry Paterson, associate technical fellow with the Boeing Engineering, Operations & Technology unit. Paterson is a member of a number of ARINC working groups and leads its Ethernet test standardization efforts.

“Airline operators would realize a ten-fold improvement” over the existing system, which is currently limited to about 1 Gigabit per second, he said.

However, the future of such a network is unclear. “We will be ready to deliver single-channel 10 Gigabit solutions within the next year,” said Prouty. “The question is when the aircraft OEMs will be ready.”

In fact, the use of high-speed Ethernet is still quite limited today, since aircraft manufacturers can often choose between Gigabit Ethernet and fiber optics to address their throughput needs, Prouty said. “The use of fiber means lighter weight and EMI (electromagnetic interference) immunity, which is attractive when compared to an electrical gigabit link,” he said.

In the case of business aircraft, high-speed Ethernet use is mainly limited to upper end VIP-type aircraft, while “the lower end corporate jets use basic Mil-Spec connectors to save cost and make an easy termination on their end,” said Tony Forst, applications engineer with Emteq, based in New Berlin, Wis.

Aircraft manufacturers and operators have, however, bought into an extensive weight loss effort, and connector makers have responded by scaling down their product offerings. “We continue to see a trend to smaller and lighter connectors and connector accessories,” said Gino Nanninga, vice president of sales with Positronic Industries, of Springfield, Mo. “The trick is achieving this goal while maintaining robustness and high performance of the connectors.”

Many connector companies have developed or are developing “the next generation of airframe qualified, small, high-density connectors,” said Ed Buttrey, president of Cable Technology, of Great Falls, Mont., an Emteq partner. “They are designing the line to be interchangeable with each other. Everyone wants to have multiple sources for connectors, which also drives the cost down.”

Getting smaller is not without its issues, including maintenance and repair. A fiber-optic fiber can be as small as 0.50 microns or about the size of a human hair, said Nanninga. Imagine trying to realign two pieces of fiber that have split in “what we call a butt splice, where you put the faces back together,” he said.

“As the densities get higher, you also have to make sure you’ve got tolerances (and) maintain things like DWV (Dielectric Withstanding Voltage) on the connectors” to prevent problems like flashover, said Wes Morgan, director of Americas Product Management with ITT Interconnect Solutions, Newton, Mass. “This is less of an issue for systems running data signals, where there is great opportunity to (develop) smaller size formats,” he said.

ITT Interconnect Solutions and other companies currently offer “nano” connectors with 0.025 inch pitch, or distance between contacts. “That is pretty much state-of-the-art for density,” said Morgan.

Fiber Connections

Size aside, many in the industry believe the most significant weight loss and throughput gains will come through increased use of fiber optics. “Fiber-optic cabling is much lighter than legacy copper cabling (and) you can put so much more data on fiber,” Nanninga said.

The use of fiber-optic technology is uneven, however, with some aircraft manufacturers “still being in the initial stages, while others are much further along in the conversion process,” said Prouty. It is “a more common occurrence in new designs,” such as the Airbus A380 and Boeing 787, and some new general aviation models, said Dave Engler, Tyco Electronics director of product management.

Few deny that fiber optics will play a large role in future aircraft systems. The questions are how big a role and how soon?

At the leading edge is the Fiber-To-The-Screen audio/video on demand (AVOD) system from Lumexis, of Costa Mesa, Calif., which entered revenue service on a FlyDubai 737-800 last November. “It is all fiber and goes in the sidewall, then up the side to the seat to the screen” and eliminates all the zone, sidewall disconnect and seat electronics boxes, “so it really challenges the existing paradigm,” said Olson. Tyco Electronics worked with Lumexis to develop and deploy the system.

However, the fiber-to-seat installation remains controversial. “Traditionally, the passenger area has been considered a harsh environment for connectors and cabling due to exposure and potential for abuse,” said Paterson. “Time will tell if the inherent sensitivities that fiber brings with it, such as susceptibility to dirt and contamination on the fiber termini … will create undue burden over the product’s life cycle.”

More broadly, expanded use of fiber optics brings with it other issues, including additional overhead costs in the way of training, tooling and time to repair, said Paterson. Similarly, Prouty observed that it is a “significant challenge to train people with the right electrical experience to apply the best practices for fiber optic cable assembly implementation.”

Investments in training will also be key to helping the user community better understand the issues related to installation and service, said Engler.

Furthermore, “at some point, the bandwidth limitations of the current generation of fiber will become an obstacle, and avionics systems may ultimately require a jump in bandwidth to an OM3 (Optical Multimode 3) or beyond, grade of fiber optic cable,” said Paterson. “Unlike changing out copper wire, any change in fiber type has a significant ripple effect in connector technology, as well as impacts to maintenance tooling and training.”

Tackling these issues involves significant investments, and the question is: “Are the airlines ready for this?” asked Paterson.

“A lot of customers are very interested in fiber optics,” and Emteq is working on a fiber optic cable solution, said Kerry Stuckart, Emteq product manager.

However, the technology is not really going to take off until equipment manufacturers start changing over the requirements for their products.

“We foresee future systems using more and more fiber,” said Prouty. “Optical backbones will probably coexist with multiple solutions (and) we need to be able to integrate any of these solutions in the most cost effective manner.”

New Products

Addressing this unsettled situation, connector companies are introducing solutions that largely address three common themes: versatility, low weight and high throughput.

ITT Interconnect’s latest ARINC 600 connector inserts have “built-in flexibility to combine copper and fiber,” Morgan said. The inserts allow for layouts that require fewer boxes and eliminate multiple panels in the avionics rack, all of which yields weight and space savings. The connectors are ideal for applications including instrument landing systems, GPS landing systems, flight navigation systems, avionics common data network systems, integrated surveillance systems and backbone Ethernet network modules, ITT said.

Positronic offers a new lightweight aluminum hood for its D-subminiature connectors, and combination D-subminiature connectors that provide signal, power, coax and high voltage contacts in a single package. Its Scorpion power connector “allows the user to configure the product size to the application (allowing) the size and density to be tailored to the need,” said Nanninga.

Emteq planned to release aerospace grade locking accessories for its high-definition multimedia interface (HDMI) connector, said Stuckart. The offering “has plug/receptacle interchangeability using our circuit board technology,” she said. “Termination of HDMI connectors is quite difficult, and we think this (offering) is going to make it easier for those who want to terminate product in the field.”

Tyco Electronics’ Quadrax connectors support 1-gigabit Ethernet requirements. In addition, the company has introduced an ARINC 600 connector “with a stamp and form size 22 contact to reduce weight,” said Engler.

Radiall boasts LuxCis, a high-density fiber-optic contact, which is a baseline for the ARINC 801 standard and responds to aircraft manufacturers’ needs to reduce size and weight, said Prouty. The company also has introduced an HDQX connector series for high-speed Ethernet and RF data transmission. Compact, rugged and lightweight, it is designed for data networks, IFE systems, video control centers and naval and military vehicle communications.

As these diverse products proliferate, there is a growing need for standards to characterize the technologies used on aircraft. The ARINC AEEC Cabin Systems Subcommittee is responding by “aggressively moving forward on standards definition for a 4th Generation Cabin Network (4GCN) in-flight entertainment system,” said Paterson. In turn, he said, “a new 4GCN Seat Distribution Network is driving development for connectors that can support either Gigabit Ethernet or fiber optic based datalinks.”

At the same time, the AEEC Ku-band technical working group is defining new equipment interface standards that support off-board Internet connectivity via satellite, Paterson said. “With the need to support several Ethernet interfaces, the Ku-band team is looking to leverage off of either existing connectors or those under development for 4GCN,” he said.

However, progress has been slow in developing an industry-wide methodology for characterizing the performance of connectors for Ethernet applications, Paterson reported. “The target for releasing a mature draft test standard,” he said, “is fall 2011.”

Next month: Antennas

Avionics Magazine’s Product Focus is a monthly feature that examines some of the latest trends in different market segments of the avionics industry. It does not represent a comprehensive survey of all companies and products in these markets. Avionics Product Focus Editor Ed McKenna can be contacted at [email protected].

Market Moves

Following are some recent developments announced by manufacturers and distributors of aerospace connectors.

âž¤ Tyco Electronics in December announced plans to change its name to TE Connectivity Ltd., subject to shareholder approval. “We are changing the name of our company to better reflect the products and solutions that we provide to our customers,” said CEO Tom Lynch. “In a world that is increasingly connected, we engineer a full range of connectivity solutions. From electronic connectors under the hood of a car, to fiber optic cables under the sea, to high-voltage connections in energy systems, our products protect and connect the flow of data and power from origination to destination in the world’s largest industries.”

âž¤ Phoenix Logistics has developed a front-end field replaceable, self-locking RF Microwave connector, the company announced in August. The PLI connector eliminates the need for lockwire/safety wire that can lead to potential foreign object debris in an aircraft. The PLI self-locking connector maintains the required torque to ensure that the connector interface remains fully engaged throughout the operational profile that any aircraft may experience. If the connector is damaged on the aircraft, rather than replacing the entire assembly, the front end of the connector can easily be replaced in the field, Phoenix Logistics says.

âž¤ KAPCO, based in Brea, Calif., in July announced the acquisition of Wings Electro Sales, of Wellington, Fla., a distributor of electromechanical components and ground support expendables. KAPCO said the acquisition falls in line with its “strategic plan to increase our electrical product offering. In addition to the expanded list of electrical products, Wings has strong existing relationships with several of the most reputable suppliers in the industry and years of technical knowledge in connector application to help us better serve our customers.”

âž¤ Souriau PA&E, of Wenatchee, Wash., in May introduced an aluminum Micro-D connector. The connector combines the lightweight characteristics of all-aluminum construction with high levels of hermetic performance, according to the company. This MIL-PRF-83513 compliant connector can be mounted to a lightweight aluminum electronic housing with laser welding or an O-ring seal, and it has an operating temperature range of -55°C to +125°C.

âž¤ Radiall, of Chandler, Ariz., in December released the NSX series Size 22 socket contact, which can help reduce the cost of ARINC 600 connectors, according to the company. The NSX Series contacts (ARINC 600 standard) are multipin rack and panel connectors used to connect high performance avionic equipment.

The contact combines a stamped and rolled clip inside a screw machined body. Use of stamped and rolled parts considerably reduces the manufacturing complexity and the cost of the contacts, Radiall says. The PC tail contacts are completely intermateable with existing ARINC 600 plug connectors, are compatible with existing pc board layouts, and are fully qualified under ARINC 600 specifications, according to the company.