It’s a discomforting thought but commercial aircraft are each struck by lightning at least once per year, according to estimates by aviation experts. Luckily, they rarely compromise flights. As passengers, we may not always notice the event, with our heads buried in airline pillows or eyes glued to a seatmate’s screen but it’s safe to say some inflight chaos would ensue if we were aware.
“[Lightning strikes] are more frequent than we would like,” Carmen Guerra-Garcia, an assistant professor of aeronautics at the Massachusetts Institute of Technology (MIT), told Digital Trends. “Aircraft manufacturers take great care to make the aircraft safe under such an event but embedding all the necessary protection is costly. Also, if struck, the repairs are costly… and, from the airline perspective, more costs are associated with having the aircraft out of service for inspections and repair.”
With their electrically conductive surfaces, planes serve as something like lightning rods in flight. Their amplified electrical fields make aircraft themselves responsible for about 90 percent of these strikes. Planes are usually rerouted to avoid storms and potential lightning, but a new idea investigated by Guerra-Garcia and her colleagues would actually see planes intentionally increase their electrical charge and fly right through the threatening storms.
Although it sounds counterintuitive — or even a bit insane — the researchers demonstrate in a report recently published in the American Institute of Aeronautics and Astronautics Journal that there is a sweet spot for an airplane’s electrical charge that that could let it avoid strikes, even in the midst of a storm.
Guerra-Garcia explained, “The idea is to have electric field sensors on the aircraft that continuously monitor the electrical environment the vehicle is subjected to. From these measurements, onboard algorithms would determine the risk of a strike and the net charge level of the aircraft required to improve the situation. The onboard controller would then command the actuators (ion emitters that can charge the aircraft) to drive the aircraft to the optimum net charge level, that which keeps equal safety margins for the positive and negative ‘leader.’”
Leaders refer to electrical causeways that branch out from a plane’s highly conductive exterior. When these causeways reach an oppositely charged region, they form a circuit, and can result in a tremendous bolt of energy hitting the plane. Through mathematical models, Guerra-Garcia and her team showed that changing a plane’s electrical potential, by charging it negatively, significantly reduced the risk of a strike.
Having presented a theoretical study, Guerra-Garcia said the next step is laboratory validation. However, she warned that this method is still some ways away from real-world applications, as it would entail advances in modeling capability that are currently not possible with onboard predictive algorithms.
