Serious questions must be answered after a power failure snarled New York's air traffic control last week. For starters, shouldn't the Federal Aviation Administration's lines be routed through dedicated circuits? It was AT&T's electronic switching system -- the company routes many other customers' circuits through that same equipment -- that ran out of juice and knocked flight controllers off the line.
Subjecting air traffic communications to the danger of such a failure is asking for trouble. Switching machines can get overloaded or, as in the tie-ups that blocked local telephone networks this summer, suffer catastrophic breakdowns. FAA communications chiefs had already proposed a new, dedicated-circuit backup system to lessen vulnerability, but bureaucratic wrangling between the FAA and the General Services Administration blocked action. That in-fighting has now come back to haunt the FAA.
The failure of AT&T's power converter, when switched over from utility power to a local generator, has not yet been satisfactorily explained. Such devices usually do not fail so completely without warning. Moreover, that single power converter was a clear weak link that should have been recognized. The company needs to install backup equipment to guarantee the safety of FAA lines at the nation's major airports.