Why Planes Survive Lightning: The Engineering Behind an IndiGo Strike at 17,000 Feet

A commercial jet is struck by lightning more often than most passengers realise — and almost every time, nobody on board notices. That basic fact of aviation engineering was back in the spotlight after an IndiGo flight suspected of taking a lightning hit landed in India with visible nose damage but no injuries.

What happened on IndiGo flight 6E925

IndiGo flight 6E925 was flying from Patna to Lucknow on October 7, 2026, around 4 p.m. local time when it ran into severe hail and thunderstorms while descending toward Chaudhary Charan Singh International Airport, according to Al-Bawaba News, which cited reporting from the Times of India. The aircraft was at roughly 17,000 feet at the time, the outlet reported, carrying 104 passengers and six crew members.

Airport personnel discovered damage to the aircraft's nose cone — the radome covering the weather radar at the front of the fuselage — only after it had landed normally, according to The Federal, an Indian news outlet. An airport official told The Federal: "The aircraft is undergoing a technical inspection and further necessary action. As part of the preliminary assessment, the possibility of the aircraft encountering lightning during adverse weather conditions is being examined."

No injuries were reported, and Al-Bawaba News said the flight arrived about eight minutes ahead of schedule despite the incident. India's Directorate General of Civil Aviation grounded the aircraft for inspection, and IndiGo arranged a replacement aircraft for later flights on the route, Al-Bawaba News reported. As of the reporting, the exact cause of the dent had not been officially confirmed — lightning remained a suspected, not confirmed, explanation pending IndiGo's technical findings, The Federal noted.

How often lightning actually hits airliners

Incidents like this are not rare. The US National Weather Service states that commercial transport passenger planes are hit by lightning an average of one or two times a year, and that aircraft often help trigger the strike themselves because their presence increases the electric field in a thunderstorm and makes a lightning discharge more likely. Despite that frequency, the agency notes there has not been a lightning-caused commercial transport airplane crash in many decades.

The University of Southern California's engineering outlet Illumin cited the same US National Weather Service figure — that nearly every commercial passenger plane is struck once or twice a year — and separately cited Statista data showing that more than 30 million commercial flights take place annually worldwide, a volume that Illumin says makes lightning strikes a statistical near-certainty rather than an anomaly.

The Faraday cage that keeps passengers safe

The core defence is known as the Faraday cage effect: a continuous conductive shell channels an electrical charge around its exterior rather than letting it pass through the interior. On aircraft with aluminum skins, such as the Boeing 737, the metal fuselage itself performs this function, according to aviation outlet Airways Magazine.

Composite aircraft like the Boeing 787 or Airbus A350 use carbon-fiber-reinforced plastic, which does not conduct electricity as well as aluminum. To compensate, manufacturers embed a layer of expanded copper foil or metal mesh beneath the composite's outer surface so the structure still behaves like a Faraday cage, Airways Magazine reported. Illumin added that engineers can also vary the mesh's wire thickness or use diamond-shaped grids to steer the current along preferential paths, directing it away from critical components such as the cockpit, engines and fuel tank.

Protecting wiring, fuel tanks and vulnerable parts

Beyond the outer skin, Airways Magazine reported that all metal components on an aircraft are electrically bonded together with minimal resistance, giving current a low-resistance path that limits dangerous arcing inside the structure. Avionics, navigation and flight-control wiring are wrapped in braided metal sheaths and backed by surge-protection devices, with the most sensitive electronics housed in their own small Faraday enclosures.

Fuel tanks receive particular attention because sparks near fuel vapor are catastrophic. Airways Magazine reported that access panels near tanks use lightning-tested sealants and bonding wires designed to prevent any spark from reaching fuel. Illumin cited Pan Am Flight 214, a Boeing 707 that crashed in 1963 after lightning struck and destroyed part of the aircraft's wing, as an example of the kind of damage that modern lightning-protection systems are designed to prevent.

Non-metallic external parts such as radomes and winglets — the same type of component damaged on the IndiGo flight — are fitted with diverter strips, often visible as segmented or zigzag patterns, that are designed to catch a strike and conduct it away from the structure rather than let it burn through, according to Airways Magazine.

What regulators require before an aircraft can fly

Lightning protection is not optional engineering; it is a certification requirement. Airways Magazine reported that the US Federal Aviation Administration's Part 25 and the European Union Aviation Safety Agency's CS-25 both mandate compliance with technical standards — including RTCA DO-160G, SAE ARP 5414 and EUROCAE ED-91A — that define test waveforms and strike-probability zones manufacturers must design against before an aircraft type is approved.

Those rules are also why a suspected strike, even one that causes only cosmetic damage, triggers a mandatory inspection. The National Weather Service notes that this inspection process, required after any suspected strike, can delay flights and be costly — exactly the sequence followed with the IndiGo aircraft, which was pulled from service for checks after landing.