Negatively charging planes could reduce mid-air lightning strikes

Commercial planes are struck by lightning roughly once a year, and the ensuing inspections can keep the aircraft out of service and adversely affect schedules. Prompted by Boeing – which sponsored the research – the MIT team looked for a way to counteract the polarisation that happens to aircraft when flying through ambient electric fields. As planes become increasingly polarised, they can set off a highly conductive flow of plasma called a positive leader — the preceding stage to a lightning strike.

The researchers developed a mathematical model to describe the electric field conditions under which leaders would develop, and how they would evolve to trigger a lightning strike. They applied this model to an aircraft geometry and explored whether changing the aircraft’s potential (charging it negatively) would prevent the leaders from forming and triggering a lightning strike. Their results, published in the American Institute of Aeronautics and Astronautics Journal, showed that the charged scenario required a 50 per cent higher ambient electric field to initiate a leader, compared with an uncharged scenario.