Missile defenses for airliners still years away.

• Position: Security beat: homeland defense briefs

Manufacturers of antimissile protection systems repeatedly have stressed that these technologies could be installed on civilian airliners relatively painlessly and within a short period.

But these assurances belie the reality that it may take years to assess whether it makes sense for the airlines to install these systems. It is not clear, for example, what impact antimissile systems will have on operations, logistics, maintenance and safety, said James Carey, vice president for business development of Avisys Inc. The company supplies an antimissile system that is competing in a Department of Homeland Security program called "counter manpads." Manpads are man-portable air defense systems, typically heat-seeking missiles that target low-flying aircraft.

"Defense contractors are running around saying we can put equipment on a commercial airplane," Carey said. "But there are no FAA (Federal Aviation Administration) regulations, policies or procedures for putting defensive equipment on commercial airplanes."

Until DHS can identify all the issues associated with putting equipment on airlines and FAA specs are defined, "we won't be putting any equipment on airplanes," he said. "There...