Light Combat Aircraft Tejas during the current-injection experiment

Lightning strikes can cause damage to the aircraft surface, disrupt electrical and electronic systems, and ignite the fuel-air mixture around the engine

Researchers at the Indian Institute of Science (IISc) have developed a computational model to simulate lightning strikes on aircraft, insights from which they said could help design better protective measures.

Lightning strikes can cause damage to the aircraft surface, disrupt electrical and electronic systems, and in extreme cases, ignite the fuel-air mixture around the engine to set off explosions.

Udaya Kumar, professor at IISc’s department of electrical engineering, said an aircraft gets struck by lightning once every 1,000 hours.

Researchers in Kumar’s lab who have been studying lightning strikes developed the model as an alternative to “grossly oversimplified” methods to identify parts of the aircraft that are most frequently hit.

The team applied the model to two different aircraft geometries – a DC10 passenger aircraft and the standard dynamics model of a fighter aircraft.

The model and the data obtained from it have been published in the peer-reviewed journal Atmosphere.

While in the downward cloud-to-ground lightning, the leaders, or precursors to the lightning arcs, are initiated at the cloud, field data and findings from the model showed that these discharges are initiated at the aircraft in more than 90% of the cases.

The study involved extensive computation of the electric field around the aircraft and suitable modeling of the electrical discharges, IISc said in a statement.

The researchers could estimate the minimum ambient electric field required for the initiation of lightning leader discharges from the aircraft.

They said these values are in line with measured data from instrumented aircraft flown through thunderstorms, such as NASA’s Storm Hazard Programme.

The model also factored in the role of atmospheric conditions including humidity and air pressure.

IISc said Kumar was earlier involved in the design of a lightning protection system for Indian satellite launch pads.

His lab also carried out an experiment on a military aircraft by injecting it with “enormous amounts of current” to emulate lightning discharge and by collecting electric field data from inside the aircraft.

The team, extending the scope of the study, is investigating the peak value of the lightning stroke current required for aircraft-initiated discharge and disruptions caused by the strike to the internal electrical equipment.

The researchers suggested that such studies can aid in “reliable quantification of the lightning threat,” and enable an optimised design of lightning protective measures in aircraft.