Avionics connectors getting more rugged for demanding market

May 6, 2009
Avionics hardware integrators are demanding today's avionics connectors be faster, lighter, and more rugged than ever before – especially those that fly on unmanned aircraft. Avionics Connector suppliers also see the avionics market climate holding steady with the military avionics sector showing growth.

By John McHale

Avionics hardware integrators are demanding today's avionics connectors be faster, lighter, and more rugged than ever before – especially those that fly on unmanned aircraft., especially those that fly on. Avionics Connector suppliers also see the avionics market climate holding steady with the military avionics sector showing growth.

"The latest trend is for faster performing connectors as well as smaller and lighter weight connectors following suit with the trend in avionics to be smaller and lighter and yet have quicker response rates," says John Binder, industry manager for the military and aerospace business at rugged connector supplier Hypertronics Corp. in Hudson, Mass. "In all cases, though, there is still a requirement for the systems to maintain or surpass the current requirements to withstand severe and extended shock and vibration."

Greg Powers, market development manager for global aerospace, defense & marine at Tyco Electronics in Harrisburg, Pa., says system integrators are looking for connectors with more "modularity – which enables user configurability and scalability; increased density; and increased functionality – a variety of functions, such as differential pair, single ended, radio frequency, optic, power, and high voltage."

Consequently the improved capability and increased functionality also requires greater power efficiency, he adds. Another trend is for higher bandwidth at about 3.125 gigahertz with some applications demanding 10 plus gigahertz performance, Powers says.

Unmanned vehicles -- in the air, on land, and at sea -- also are placing big demands on connector designers. "The number-one law of a connector is it must mate; things fail because they loose their connectivity," Binder says.

"For the unmanned market, avionics will need to be more rugged to accommodate the Federal Aviation Administration's (FAA's) requirements of flying in national airspace," he continues. "Unmanned systems will require even greater levels of shock/vibration/environmental resistance as these vehicles operate at higher, deeper, and longer missions with increase G's and vibration. This will force the avionic systems to be significantly smaller and lighter, yet maintain or surpass the ruggedness of existing systems.

"If it's unmanned, you can go substantially higher than 10 Gs -- providing your vehicle can take it," Binder adds.

Unfortunately, many connectors available today cannot operate reliably through forces as strong as 10 Gs. "If your connector fails, you will lose signal, or you will lose power, and your system will fail," Binder says.

Down the road Binder says he foresees avionics systems getting smaller and faster, using more capabilities from embedded computing standards such as VPX, Compact PCI, and PC104. Architectures in 3U and other small form factors with "increased computing power and speed to facilitate upgrades and enhance capabilities will be more readily incorporated in avionics systems."

Hypertronics offers the Hypertac system, which uses pin sockets with wire baskets that hug the contact pin as the pin is inserted in the socket. "It is always in continuous connection with all these wires to the pin," Binder explains. The wire basket inside the connector is ruggedized in a barrel construction to withstand extremes in shock and vibration.

Avionics connectors that use the Hypertac system include the Hypertronics KFT and PC104 line of connectors, Binder says. "KFT is a miniature, low-profile high-density mezzanine connector and the Hypertronics PC/104+ is a high performing connector interchangeable with commercial-off-the-shelf products to allow for ultimate interconnect reliability."

Another trend in design is to make connectors more compatible with cooling technologies, Tyco's Powers says. "The connectors often need to share space with different cooling schemes, including free air convection, forced air convection, conduction, and liquid flow through, etc."

Tyco's rugged connector line includes their "VITA 46 VPX Compliant MULTIGIG RT2 Backplane Connector and our work with the VITA committees to introduce fiber optic (VITA 46.12) and RF (VITA 46.14) modules to expand functionality," Powers says. They are used in avionics line replaceable modules (LRMs) as are "our new High Speed Ruggedized (HSR) Backplane Connector."

Tyco also offers "fiber optic and Quadrax variations of ARINC 600 and general purpose rectangular connectors," he adds.

Ruggedizing connectors also is a primary goal of Winchester Electronics Corp. in Wallingford, Conn. "We are developing a product that is anti-rotational after it is torqued, so it stays in place," says John P. Murphy, strategic customer manager at Winchester Electronics.

Aircraft systems designers are particularly sensitive to connectors that use nuts and screws that can come loose after exposure to long-term shock and vibration -- even to the extent of using nuts with holes in them that are used to wire the nut to the aircraft bulkhead.

The problem with nuts and screws that come loose is known as foreign object debris (FOD) damage, which can happen when small bits of debris like nuts and screws gets sucked into jet engines while on the tarmac. This can cause costly damage and take aircraft out of service.

Murphy says the major trends he sees in the rugged connector business are light weight, composite construction, ruggedization, and nuts and screws that cannot inadvertently come loose.

A positive trend for connector companies is that the avionics market remains quite steady despite the current global recession.

"For the most part, the market is holding its own," Hypertronics' Binder says. "In this economic downturn, the avionics industry mirrors the aircraft industry. For the commercial segment, the slowdown with Boeing (and the airlines) has slowed the need for new avionics systems. FAA rule changes also influence the need for retrofit avionics systems, but even that has slowed down.

"Overall, we remain optimistic," Tyco's Powers says. "Certainly the downturn in commercial aviation is rapidly taking its toll in general aviation, as with the business and regionals, and impacting the larger commercial transports and cargo somewhat more slowly. If the economic downturn is short-lived, the inertia in the market should ease the long term impact. Only time will tell how far the commercial dip will extend. We look forward to upgrades such as the Automatic Dependent Surveillance–Broadcast (ADS-B) program and new efficient airframes, including the Boeing 787 and Airbus A350."

"For the military market, the real concern was the uncertainty of the new administration's decisions," he continues. "Now that those decisions are understood; the F22 is slowing down, the F35 is ramping up and the unmanned market is expanding, I believe the military avionics systems market will shortly be back on its growth track."

Tyco's military market out look is similar.

"The military market remains fairly stable," Powers says. "The ramp of the F-35 and UAVs, coupled with continued build/upgrade of legacy airframes such as F-15, F-16, F-18, C-130, Blackhawk, etc., should sustain the market while emerging programs are resolved and come on line. Again, upgrades and electronics systems such as command, control, communications, computers, intelligence, surveillance, and reconnaissance (C4ISR) focused programs will help the market."

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