Editor’s Note: Lead-Free Avionics?

By David Jensen | September 1, 2004
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It's hard to believe that something as small as solder on a circuit board can cause a stir in a multibillion-dollar industry that builds and operates fast-moving, multiton vehicles. But it has.

On Aug. 10-11, members of the commercial aviation industry gathered at ARINC headquarters in Annapolis, Md., to discuss the consequences of, and response to, two European Union (EU) directives impacting aircraft electronics. The Airline Electronic Engineering Committee's (AEEC's) Future Concepts for Maintenance (FCM) subcommittee joined with members of the Avionics Maintenance Conference (AMC), regulatory officials, and representatives of aerospace organizations and of the avionics and airframe manufacturing community in an "exploratory meeting" to determine actions in response to Directives 2002/95/EC and 2002/96/EC. Both mandates are designed to reduce the use of hazardous substances.

Directive 2002/95/EC forbids the inclusion of lead (among other substances) in all electronic products put on the market beginning July 1, 2006. Lead is a carcinogen and can cause pollution. Legislation similar to the EU directive exists in Japan and is being considered in China and the United States.

Directive 2002/96/EC covers the disposal of waste electrical and electronic equipment (WEEE). Together, the directives are far-reaching, extending well into the aircraft electronics market.

According to Larry Carpenter, director of engineering and maintenance at ARINC, an avionics system can comprise as much as 5 percent lead. A tin-lead alloy is commonly used for solders on circuit boards because the combination of metals forms a good conductor and melts at relatively low temperatures. (However, the tin in the alloy can create "whiskers" on plated electrical leads and printed circuit boards, which can be hazardous, as David Evans reveals in his Safety column on page 55.)

Initially, the impact of the hazardous substance directives on the aviation industry would appear to be limited. Exempted from the directives are electronics in equipment for the military and national security. The air transport community reportedly is exempt, as well. This would make sense, since aircraft electronics contribute little to the lead waste problem; unlike consumer electronics, avionics are not readily discarded.

But, in truth, the EU directives undoubtedly will impact the aerospace industry. At the very least, according to an ARINC report, they will "be disruptive" to the industry. The aerospace industry has no clout to forestall the European Union mandates, since it represents only 1 percent of the electronics marketplace (with consumer electronics, computers and telecommunications comprising close to 90 percent).

The aerospace industry, therefore, can do little more than determine how to adapt to the directives. "The aerospace industry is being swept along by a supply chain that is beyond its control," says the ARINC report.

The airframe and avionics manufacturers already are preparing to comply with the EU directives. Both Airbus and Boeing have established plans to make their aircraft lead-free. However, no manufacturing standard for lead-free electronics, as yet, exists--an issue that should be addressed.

But switching the industry to lead-free products only takes care of new systems and aircraft. The major issue to aviation is the maintenance and replacement of existing systems. To avoid the worst-case scenario of abruptly replacing all lead-embedded avionics with lead-free systems in fielded aircraft, the aerospace industry must draw up a transition plan. This will be no small task. The plan must assure safety, yet not be cost-prohibitive. According to Carpenter, finding an inexpensive substitute to lead "won't be easy."

There also is the question of whether, during the transition, a mixture of lead and lead-free components can safely exist in avionics systems. The regulatory community, always seeking consistency in product quality, "is very concerned about the lead and lead-free mixture," says Carpenter.

Standards and guidelines regarding systems manufacturing, repair and replacement are urgently needed. An AEEC working group already is establishing guidelines for lead-free soldering. But the deadline to comply with the two directives is less than two years away--which means much activity toward a lead-free transition must quickly advance beyond the exploratory phase.

Buyer's Guide Correction

In the production process of the Avionics Magazine Buyer's Guide, mailed in July, the product entries on page 30 were presented incorrectly and, as a result, some entries are missing. We have reprinted page 30, with the correct product entries, along with corrections to entries on other pages, and have included it in this issue (between pages 62 and 63) as a pull-out. We regret the inconvenience to our readers.

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