While it may sound unnerving (or downright terrifying), planes get struck with lightning annually, although the chances of you having a first-row seat to the electric display are rare.
At Vancouver's YVR Airport, planes are often grounded during inclement weather, particularly when that weather includes dangerously heavy snowfall, powerful winds, or lightning.
But it may surprise you to find out that the reason planes still take off during a thunderstorm has more to do with what happens on the ground than in the air -- and not all planes are created equal (and not only when it comes to weatherproofing, of course).
Does lightning strike aircraft very often?
Lightning strikes commercial passenger aircraft one or two times annually in the United States. However, our neighbours to the south operated upwards of 16 million flights in 2022, according to the latest data from the Department of Transportation's Federal Aviation Administration.
But lightning struck a little closer to home on a recent flight connecting Vancouver with Victoria.
A Helijet with 12 passengers and two crew on board was struck by lightning over Haro Strait, resulting in “a very large bang and a white light,” according to Helijet chief executive officer Daniel Sitnam.
While the helicopter lost two of four tail rotor blades when it was struck, the pilots were able to land the aircraft, and no one was injured.
What happens when lightning strikes an aircraft?
Modern aircraft are comprised largely of aluminum, and the fuselage (the body of the plane) acts as a conductor for lightning. In other words, it prevents the electricity from penetrating the aircraft.
Dr. David Michaelson, Director of Electrical Engineering at the University of British Columbia (UBC), says commercial aircraft manufacturers take lightning seriously, noting that there haven't been any crashes caused by it since the 1960s.
He noted that the plane itself acts as a Faraday cage -- an enclosure used to block electromagnetic fields -- by moving a lightning strike's "immense amount of current" along the outside of its fuselage.
In recent years, one of the big challenges the aircraft industry has been finding composite materials to use instead of aluminum that will still keep passengers safe. For example, the Boeing 737 is comprised of roughly 80 per cent aluminum, while newer aircraft, such as the Boeing 787 Dreamliner, use a great deal of common materials to reduce weight.
Not only are planes designed to withstand lightning, but they also may generate it. In a thunderstorm, they can trigger a lightning strike as they move through the clouds since they enhance the ambient electric fields around them.
This is what Michaelson suspects happened to the Helijet that was travelling from Vancouver to Victoria, but he notes that helicopters aren't built to withstand lightning the way that planes are.
What happens when other aircraft are struck by lightning?
In November 1969, the Apollo 12 spacecraft launched on an expedition to the moon. The weather forecast didn't include any thunderstorms in the area, yet lightning struck the spacecraft twice, resulting in issues with the command modules, navigation, and guidance.
"In this case, there was no actual lighting in the area but the spacecraft picked up the negative charge as it flew to the atmosphere. There was a positive charge in the upper atmosphere and the upper part of the clouds and there [were two lightning strikes] that took a big, long ionized path down to the ground because of the exhaust from the Saturn V rockets," Michaelson explained.
Triggered events like this are the most common way that aircraft are affected by lightning. The aircraft picks up a negative charge and then the charge dissipates into the surrounding clouds, causing the reaction.
There are some places in the world where this type of process is more common, too. The North Sea, which is located between Great Britain, Denmark, Norway, Germany, the Netherlands, Belgium, and France, typically sees a higher rate of triggered lightning from October through March. This is because unstable polar air is moving right above the relatively warm sea.
While triggered lightning can happen anywhere, most commercial aircraft are designed to withstand the strikes. But helicopters are much more susceptible to them.
Helicopter rotors are more fragile than aircraft structures and may be damaged by lightning directly. "And if that happens, then you're in really bad shape," Michaelson pointed out.
Lightning can also disrupt the airflow around the helicopter's engine, while planes tend to have their engines spaced out far enough that a lightning strike wouldn't affect both.
Do planes ever get damaged by lightning?
Transport Canada spokesperson Sau Sau Liu told V.I.A. that lightning can strike an aircraft and puncture its skin, "damaging electronic equipment, causing engine failure, and inducing permanent error in magnetic compasses."
However, Canadian pilots receive substantial meteorological training to understand weather information. When planning a flight, they are required to review the latest aviation weather information to determine if the flight they are preparing for can be conducted safely.
"When a lightning strike happens to an aircraft airborne, it is considered an abnormal occurrence, and the aircraft needs to be inspected by maintenance after landing," she explained.
"Of course, if evidence of damage or abnormal aircraft behaviour occurs, the situation becomes an airborne emergency for which the appropriate course of actions can vary widely depending on the circumstances."
Transport Canada's Aeronautical Information Manual provides information on the risks associated with flying in the vicinity of thunderstorms, and recommends avoiding by at least 20 nautical miles any thunderstorm identified as severe or giving intense radar returns.
Does it need to be raining for lightning to strike?
There are several misconceptions about what lightning is and what it is capable of doing. For one, many people wrongly assume that hiding under a tree will keep them safe during a storm. However, 20 per cent of lightning deaths occur from people who have taken cover beside or in a tree; a building or vehicle provides a much chance of staying safe.
Lightning often occurs in a place that is experiencing heavy rainfall, but it can also strike outside of a stormy area. In fact, it may strike upwards of 16 km away from a storm. Anyone who can hear thunder is "at risk of being struck by lightning and should take shelter immediately" and stay there for at least half an hour after the "last rumble of thunder," according to Environment Canada.
Thankfully, the Metro Vancouver weather forecast doesn't include many thunderstorms, particularly compared to the B.C. Interior. The cold water of the Pacific Ocean and the mountainous terrain break up the majority of storm systems from gaining momentum. But storms are possible, along with lightning, virtually any time of the year, according to Environment Canada Meteorologist Derek Lee.
Places with flat terrain, such as the Prairie provinces, see significantly more thunderstorms.
How does YVR airport monitor thunderstorms?
Vancouver International Airport (YVR) continuously monitors advanced weather forecasts to prepare for and mitigate potential effects on operations including the possibility of lightning events.
"When lightning, or the threat of lighting, exists in the immediate vicinity of the airport, arrivals, departures, and ground operations may be halted temporarily. This is a measure to ensure the safety of travellers, aircraft, Sea Island employees, and our community," YVR told V.I.A.
Lightning protocol varies between airlines, however, with each one utilizing specific safety measures and guidelines that have been "tailored to the unique characteristics and equipment of their aircraft."
At all times – but especially during inclement weather – travellers departing from YVR are reminded to check the latest flight details online or before coming to the airport.
With files from Louise Dickson
