Here's what happens when a plane gets struck by lightning

Aircraft can be struck by lightning more frequently than you may expect, often several times a year for commercial aircraft that are operating tightly packed flight schedules. Normally, any impact is minimal, and flights are able to continue as planned. However, a lightning strike can sometimes lead to disruption to passengers and services.

Air New Zealand's grounded Boeing 787-9

This was the case in December 2024, when an Air New Zealand Boeing 787-9 Dreamliner was struck by lightning, causing a flight from New York to Auckland to be canceled. The aircraft, registered as ZK-NZL, remained on the ground overnight at New York John F. Kennedy International Airport (JFK) before departing back to Auckland Airport (AKL) in New Zealand the following day after undergoing a series of maintenance checks.

The affected passengers were eventually either re-routed via the carrier's flights from San Francisco International Airport (SFO) or booked onto later services from New York. Air New Zealand and its fellow Star Alliance member United Airlines both offer daily flights between San Francisco and Auckland with their Boeing 787-9s, allowing for multiple rebooking options.

When contacted by Simple Flying about the incident, a spokesperson for Air New Zealand said,

"The aircraft scheduled to operate NZ1 from New York to Auckland on Monday evening (local time) required additional inspections following a lightning strike. The time to complete these required engineering inspections exceeded the crew's maximum duty hours, resulting in the cancelation of the flight. Customers were assisted with overnight accommodation in New York and rebooked to travel on alternative services. We sincerely apologize for the inconvenience this has caused and appreciate the patience and understanding of our customers."

The latest data from ch-aviation shows that the aircraft in question was delivered new to Air New Zealand in October 2017, making it more than seven years old. It is one of 14 787-9s operated by the carrier, each capable of carrying up to 275 passengers in a three-class configuration - 27 in business class, 33 in premium economy, and 215 in economy class.

However, lightning strikes do not normally lead to any major safety issues for the aircraft or disruption for the airline and its passengers. For example, in March 2024, an Air Canada Boeing 777-300ER was hit by lightning when taking off from Vancouver International Airport (YVR) en route to London Heathrow Airport (LHR).

The lightning was deemed to have not caused any damage to the aircraft, and the flight continued towards London as normal. At the time of the incident, a spokesperson for Air Canada said,

"These aircraft are designed in order to take this type of lightning strike. Actually, aircraft often initiate the strike because their presence enhances the ambient electric fields typical for thunderstorms and facilitates electrical breakdown through air.

What happens when an aircraft is struck by lightning?

Lightning strikes most commonly occur when an aircraft is passing through clouds - in fact, according to DTN, around 90% of all lightning strikes take place in clouds, usually at an altitude of 5,000 - 15,000 ft. Lightning typically strikes the extremities of the aircraft, such as the wing tip or the nose.

Often, the flight will continue as normal despite the lightning strike. However, if the onboard flight crew ascertains that the aircraft's displays or systems have been affected, they may choose to divert the flight to the nearest airport.

The aircraft skin acts as a conductor, allowing the lightning to exit the aircraft again without damage. Aircraft are also manufactured with a Faraday cage design, which means that should it be struck by lightning, the lightning charge can enter and exit the aircraft without impacting the inside of the aircraft and its passengers.

The aircraft itself normally remains unharmed or suffers only minor damage. DTN explains the Faraday cage design in the following way:

"A Faraday cage is designed to block electromagnetic fields when the ‘cage’ is covered by continuous conductive material which keeps people safe inside. Planes and cars are both fitting examples of Faraday cages, which keep you safe when lightning strikes."

In addition to the Faraday cage design, aircraft are painted with anti-static paint, which means that a lightning strike does not damage the aircraft. The aircraft's fuel tanks are also lined with liquid seals, protecting them from any potential damage caused by lightning strikes.

When it comes to the aircraft's electrical wiring, this is also insulated to protect it from lightning strikes, which means that the aircraft is able to continue operating in the event of a lightning strike, with the pilots retaining control of its vital onboard systems.

Crashes caused by lightning

One of the last confirmed crashes of a commercial aircraft due to a lightning strike was Pan Am Flight 214 in December 1968. The aircraft, a Boeing 707, was traveling from San Juan to Philadelphia via Baltimore when it was struck by lightning over Maryland on the second leg of its journey. The subsequent crash killed all 81 passengers and crew members onboard, and became Pan Pam's first fatal accident with the 707.

An investigation by the Civil Aeronautics Board at the time concluded that the likely cause of the crash was a lightning strike that ignited fuel vapor in one of the Boeing 707's fuel tanks, resulting in an explosion. Witnesses reported seeing the aircraft in flames as it crashed towards the ground. As a result of the crash, further research was carried out into making aircraft fuel tanks more resistant to the impacts of a lightning strike.

The US Federal Aviation Administration (FAA) went on to publish guidance on how this could be achieved. For example, the minimum thickness of the aluminum surfaces on the aircraft's wings was increased in order to reduce the potential for lightning to melt through the wing's surface and reach critical components of the aircraft.

The FAA also mandated electrical bonding between the surface of the aircraft and any items installed on the surface of the wings near the tanks, such as:

• fuel filler caps
• drain valves
• access panels.

Unfortunately, just three years later, another deadly crash occurred caused by a lightning strike. LANSA Flight 508 was flying from Lima to Iquitos via Pucallpa in Peru when it was brought down in December 1971. The crash killed 91 of the 92 people onboard, making it the deadliest aircraft crash due to a lightning strike in history. The 17-year-old sole survivor was able to trek through the jungle for ten days before finding help.

What to do in the event of a lightning strike

In the unlikely event of an aircraft being struck by lightning, any impact is likely to be minimal. However, it can still be a frightening experience for those onboard. On its website, the Turkish carrier Pegasus Airlines lists some key pieces of advice for passengers should they find themselves onboard an aircraft that has been struck by lightning:

• Do not stand up in case of a lightning strike or turbulence. Remain calm by following the instructions of the flight attendants
• When the electricity is discharged through lightning, it can create explosion sounds. But there is no need to worry
• Do not forget that the aircraft are engineered with similar types of equipment like lightning conductors. That is why it is impossible for you to get harmed by lightning
• You can try comforting the passengers next to you after a lightning strike or wait for further assistance from flight attendants.

As we have seen, lightning strikes occur more often than people may think, but it is still a fairly rare occurrence, especially considering the number of commercial aircraft in the sky at any one time. That said, if it does happen, modern aircraft design and technology mean that it is unlikely to pose any significant threat to the safety of the aircraft. That said, it can still lead to operational disruption in the event of a flight being diverted or an aircraft grounded while safety and maintenance checks are carried out.