the airbus 340 is an hour or so into its 11-hour flight from Hong Kong to Auckland, New Zealand. Twelve kilometers below, the islands of the Philippine archipelago are sliding by off to starboard. That’s when, deep inside one of the plane’s four General Electric-made engines, small bits of insulating skin begin to peel off and fly out the back. Their departure breaches the surface and opens tiny passageways into the compartment where the jet fuel burns. As cold outdoor air seeps in, the compartment’s temperature starts to drop.In the cockpit, the pilots are aware of none of this-the deviations are still too small to show on their instruments. But the event has not gone unnoted. For starters, a thermocouple in the engine compartment has recorded the slightly depressed temperature. Then, three hours into the flight, the onboard computer that has been collecting readings from the engines uploads the data to a satellite, which relays the information at light speed to a computer in Glendale, OH, just north of Cincinnati. This machine notices the temperature anomaly, and after taking into account other sensor readings, as well as details about the particular engine’s maintenance history, correctly identifies the likely cause: delamination of the skin covering the engine’s thrust reverser. The situation poses no immediate danger to the aircraft. But the airline is notified by telephone, and when the plane arrives in Auckland, mechanics are waiting with the parts needed to repair the skin. They finish in time for the aircraft to leave as scheduled on its next flight.
Five years ago, this could not have happened. The delamination would have worsened gradually, flight after flight, until a mechanic noticed it in the course of a visual inspection. By that point, it would have required extensive and expensive repairs that would probably have forced the delay or even cancellation of the aircraft’s next flight and possibly kept it out of service for days or weeks. But today, thanks in large part to sophisticated new statistical techniques that make it possible to detect previously invisible patterns in data, remote monitoring and diagnostic devices are able to spot many problems as soon as they occur-and sometimes even before. “Doctors talk about people in the future walking around with heart-monitoring devices that will give advance warning of heart attacks and other problems,” says Gerald Hahn, the recently retired founder and manager of General Electric’s Applied Statistics Program in Schenectady, NY. But with complex machinery like aircraft engines and locomotives, he says, “we’re already there.”
To date, remote monitoring has been applied mainly to big-ticket items where unexpected breakdowns can cost a company tens or hundreds of thousands of dollars. “In the next few years, remote monitoring will be included in the majority of car models,” says Laurence Fourchet, an analyst with the market research company Frost and Sullivan. The promise, she says, is the same that has driven airlines and railroads to install the systems: to sniff out clues that a system is heading for a failure so that preventative action can be taken. Ideally, Fourchet explains, “someone will tell you that sometime in the next few days you need to check the engine-before the breakdown occurs.”
This trend toward self-diagnosing systems appears headed for even greater ubiquity, as efforts are already under way to develop similar capabilities for household appliances like refrigerators, washers and dryers. In the not-too-distant future, an engineered world studded with sensors, computing chips and communications ports, and embedded with sophisticated mathematical tools, could banish the cost and headaches of machine downtime.