- Frequent lightning strikes on aircraft are part of daily life, occurring almost daily without catastrophic consequences.
- Lightning incidents are more likely during take-off and landing, especially at lower altitudes ranging from 5,000 to 15,000 feet.
- Modern jets incorporate design features like static wicks and specialized lightning protections in vulnerable areas, ensuring passenger safety.
Embarking on a flight amidst turbulent weather conditions isn’t anyone’s ideal scenario. Yet, lightning encounters with aircraft are surprisingly commonplace, happening more often than one might anticipate. Despite this, the skies aren’t filled with falling planes during electrical storms. So, what exactly unfolds when lightning strikes an aircraft?
Routine Lightning Encounters
Aircraft worldwide experience frequent lightning strikes, averaging about once or twice a year for a commercial plane, as reported by the US National Weather Service. The likelihood of lightning strikes varies based on factors such as the aircraft’s flight frequency – planes with more take-offs and landings face a higher probability.
Geographical location also plays a role, with lightning being more prevalent near the equator due to warm air convection currents. For instance, regions like Florida, experiencing around 100 thunderstorms daily, encounter more lightning incidents than the West Coast, with an average of only 10.
Navigating Lightning-Prone Altitudes
For seasoned travelers braving thunderstorms, it’s evident that lightning frequents specific phases of flight. Lightning strikes are notably more common just after take-off and before landing compared to other flight stages.
The ideal range for lightning activity lies at lower altitudes, typically between 5,000 and 15,000 feet. A comprehensive survey of US commercial jets reveals that aircraft flying above 24,000 feet experience an almost negligible percentage of lightning strikes.
Navigating the Skies: Lightning and Aircraft Encounters
Lightning in the Clouds
Most lightning encounters unfold amidst the clouds, with a mere 3% happening below and less than 1% above, between, or beside them. Not all clouds play host to lightning; it’s the towering Cumulonimbus clouds that orchestrate the symphony of hail, thunder, and lightning.
Lightning’s Aerial Ballet
Around 70% of lightning strikes align with rainfall, occurring at nearly freezing temperatures during flights. The electrifying dance unfolds as lightning connects with protruding aircraft parts, like the nose or wing tip. The aircraft becomes a conduit for the flash, utilizing its metal fuselage as a protective Faraday cage, guiding the voltage along the exterior.
Static Wicks and Lightning Safeguards
A glance out of your cabin window might reveal metal rods protruding from the wing’s trailing edge – static wicks. These ingenious features dissipate static charge induced by lightning, contributing to a safer flight experience.
Modern Marvels in Aircraft Design
Contrary to initial unease, modern jetliners are designed with lightning encounters in mind. As per a 2018 TIME Magazine article, the last direct lightning-induced commercial plane crash dates back to 1967. Rigorous lightning tests during certification ensure that aircraft can weather such strikes.
In the contemporary aviation landscape, composite materials are taking flight alongside traditional metals. For instance, the Boeing 787 Dreamliner boasts a 50% composite weight, including its fuselage, while the Airbus A350 embraces 53% composite materials, marking a resilient evolution in aircraft design.
Crafting a Shield Against Lightning: Aircraft Materials and Protections
Composite Challenges
Materials like carbon fiber laminate, though excellent for their lightness and strength, lack metal’s electrical conductivity. To counter this, in lightning-prone regions, composite parts undergo fortification with additional lightning safeguards.
Meshing with Lightning
Enter the lightning mesh—a conductive layer woven from materials like copper foil. The Airbus A350’s lightning mesh found itself in the spotlight during a dispute between Airbus and Qatar Airways over paint peeling. The dispute revolved around concerns that damage to the lightning mesh could pose a fire risk to fuel tanks. While the matter led to a court settlement, no admission of liability emerged.
Lightning’s Exit Strategy
Lightning often exits an aircraft through its extremities, like the tail tip, seeking the opposite polarity in the clouds. In some instances, passengers witness flashes and hear bangs as the aircraft becomes part of a cloud-to-ground lightning event. Pilots have reported momentary light flickers and instrument glitches due to the immense voltage—300 million Volts, dwarfing household voltage by 2.5 million times.
Battling Indirect Lightning Effects
The aircraft’s metal skin shields the delicate wiring, yet “indirect lightning effects” can occur. Components below the surface may face unwanted interference. Critical circuitry requires dedicated protection—shielding, grounding, insulation, and surge suppression. Boeing underscores the potential for intense strikes to harm electrically controlled fuel valves, generators, power feeders, and electrical distribution systems.
Flames Kept at Bay
In the realm of sparks, protecting flammable substances like fuel is paramount. Structures around fuel tanks undergo robust construction to resist lightning-induced “burn-through.” Vents, access points, and caps adhere to stringent lightning protection certification standards, ensuring a robust defense against potential hazards.
Navigating Storms: Aircraft Safety in Lightning Strikes and Beyond
Lightning Lessons
Safety standards evolved following a tragic incident involving a Pan Am Boeing 707, exploding mid-flight after a severe lightning strike ignited fuel vapors. Today, fuels with less volatile vapors are standard, reducing the impact of such strikes.
Post-Strike Protocol
If lightning strikes, pilots meticulously check systems for functionality. In rare serious cases, the aircraft diverts for an emergency landing. Despite potential delays and costs, thorough ground checks follow every lightning encounter, pushing pilots to avoid thunderstorms when possible.
Lightning Strikes: Rare Culprits
Most lightning encounters are benign, with incidents causing major concern being exceedingly rare. In 2023, Av Herald reported over 15 incidents, including one accident involving a Singapore Airlines 787. Delta’s A220 declared an emergency due to a lightning strike but landed safely. However, Jetstar’s Boeing 787 Dreamliner faced considerable damage, taking weeks to return to service.
The Inside Advantage
Surprisingly, the risk of lightning to individual safety seems higher for those outside the plane. Tragedies like the Vietnam Airlines maintenance worker’s death in 2021 highlight this vulnerability.
Turbulence Troubles
Beyond lightning, turbulence poses a common threat, with ‘clear air turbulence’ expected to rise due to climate change effects. While technology aids prediction and avoidance, the skies may witness more turbulence events in the future.
Freezing Fog: A Silent Hazard
Among environmental dangers, freezing fog demands vigilance. Engine performance and long-term health, coupled with visibility concerns, make it a crucial factor in aviation safety protocols.
