The FAA’s lightning rules split cleanly in two. For aircraft, federal regulations are detailed and demanding: every transport-category airplane must be designed to survive a strike without catastrophic damage to its structure, its critical electronics, or its fuel system. For airport ramp operations, there is no equivalent federal mandate. No FAA rule sets a nationwide radius at which ground crews must stop working, and no federal regulation dictates how long to wait before returning outside. That decision belongs to individual airports, airlines, and ground handlers, guided by industry practice and OSHA’s general-duty obligations.
What the FAA Requires of Aircraft
Commercial airliners are struck by lightning roughly once or twice a year on average, and FAA certification is built around the premise that a strike should never bring one down. Three regulations do most of the work.
Structure. 14 CFR § 25.581 requires transport-category airplanes to be protected against “catastrophic effects from lightning.” Metallic components must be bonded to the airframe or designed so a strike will not endanger the airplane. Nonmetallic components must either be designed to minimize strike effects or incorporate a means of diverting electrical current safely away from critical systems.1Cornell Law Institute. 14 CFR § 25.581 – Lightning Protection
Electrical and electronic systems. 14 CFR § 25.1316 governs the systems that keep an airplane flying. Systems whose failure would prevent continued safe flight and landing must be designed so their function is not adversely affected during or after lightning exposure, and they must automatically recover normal operation afterward. Systems whose failure would only reduce capability or crew responsiveness must still recover in a timely manner, under a somewhat less stringent standard.2Cornell Law Institute. 14 CFR § 25.1316 – Electrical and Electronic System Lightning Protection
Fuel systems. 14 CFR § 25.954, amended by a final rule effective November 19, 2018, requires applicants to demonstrate that fuel system design and installation prevent catastrophic fuel-vapor ignition caused by lightning. The rule replaced an older “triple-redundant fault tolerance” approach with a performance-based standard: manufacturers must show that a catastrophic fuel-tank explosion is “extremely improbable,” accounting for potential failures, the probability of a critical strike, and fuel-tank flammability exposure. Applicants also have to establish airworthiness limitations so that lightning-protection features remain effective across the aircraft’s life.3Federal Register. Transport Airplane Fuel Tank and System Lightning Protection
Physical protection typically works through overlapping design strategies. An aluminum fuselage acts as a Faraday cage, conducting current around the outside of the airframe. Composite aircraft incorporate conductive meshes or foils in the skin to do the same job. Bonding strips and grounding wires join structural components into a continuous electrical circuit to prevent arcing at joints. Static dischargers on trailing edges bleed off residual charge after a strike. Fuel systems get special attention: structural joints, hinges, and fasteners are designed to prevent sparking, and some aircraft use nitrogen inerting to reduce ullage flammability. Avionics are shielded, grounded, sheathed with braided metal, and paired with surge-suppression devices.4Flight Safety Foundation. Ground Strike
How Manufacturers Prove Compliance
The FAA supplements its regulations with advisory circulars explaining acceptable methods of showing compliance. The current guidance for electrical and electronic system protection is Advisory Circular 20-136C, issued on May 15, 2026, which replaced AC 20-136B. It covers compliance with 14 CFR 23.1306, 25.1316, 27.1316, and 29.1316 for new type certificates and changes to existing ones. The AC is not itself a regulation, but the FAA states that an applicant who chooses to use its methods “must follow it in its entirety.”5FAA. AC 20-136C – Aircraft Electrical and Electronic System Lightning Protection
Under the framework carried forward from AC 20-136B, systems are assigned a certification level tied to the severity of their potential failure: Level A for catastrophic, Level B for hazardous, and Level C for major. Compliance turns on comparing Equipment Transient Design Levels (what a system must withstand) against Aircraft Actual Transient Levels (what a strike will actually induce on wiring). For Level A systems, the design level must exceed the actual transient level by a factor of two. Redundancy alone is not enough at Level A, because a strike can induce transients across all electrical wiring at once.6FAA. AC 20-136B – Aircraft Electrical and Electronic System Lightning Protection
For fuel systems, AC 25.954-1 walks manufacturers through a structured safety assessment. Protection features are categorized as intrinsically safe (no foreseeable failure modes), fault-tolerant (a failure will not create an ignition source), or non-fault-tolerant (a single failure combined with a critical strike could create an ignition source). Non-fault-tolerant features face the most intensive scrutiny, requiring detailed analyses to demonstrate that overall risk remains extremely improbable.7FAA. AC 25.954-1 – Fuel System Lightning Protection
The FAA does not develop lightning-test procedures in-house. It recognizes SAE International and RTCA standards as acceptable methods. SAE ARP 5416A describes test methods for evaluating lightning effects on structures, components, electrical systems, and fuel systems. SAE ARP 5577 covers direct-effects certification for structures, mechanical and hydraulic systems, and external components. AC 20-155A identifies both as acceptable, though not mandatory, means of compliance.8FAA. AC 20-155A – Certification of Aircraft Electrical/Electronic Systems for Operation in the Lightning Environment Equipment-level induced-transient testing follows RTCA/DO-160, Section 22.6FAA. AC 20-136B – Aircraft Electrical and Electronic System Lightning Protection The FAA also maintains a reference work, the Lightning Protection of Aircraft Handbook (DOT/FAA/TC-22/11), published in November 2022 as an update to a 1989 predecessor.9U.S. DOT ROSAP. Lightning Protection of Aircraft Handbook
What the FAA Does Not Require on the Ramp
This is where the FAA’s role surprises most people. No federal regulation requires airports or airlines to halt ramp operations when lightning approaches. No FAA rule sets a critical-distance radius. No federal standard prescribes a wait time before crews return to the tarmac. Ramp closure decisions, and the criteria for reopening, rest with individual airports, airlines, and ground-handling companies.10Earth Networks. The Ultimate Lightning Guide for Airport Operations11Transportation Research Board. ACRP Report 8 – Lightning-Warning Systems for Use by Airports
The FAA also does not mandate any particular lightning-detection system. ACRP Report 8, published with FAA sponsorship, recommends that all commercial airports with scheduled operations in lightning-prone areas have detection and warning systems, but the choice of technology is an airport-level decision. And there is no federal requirement to report lightning-related ramp incidents or follow a standardized protocol. Airports and airlines maintain “very different procedures and standards” for identifying and responding to the hazard.11Transportation Research Board. ACRP Report 8 – Lightning-Warning Systems for Use by Airports
Who Fills the Gap
Two things fill the space where a federal ramp rule might sit: industry best practice and OSHA.
The most commonly cited industry benchmark is the “30/30 rule,” which recommends halting outdoor activity after a cloud-to-ground strike within six statute miles (a 30-second gap between flash and thunder) and waiting 30 minutes after the last such strike before resuming. An FAA working group has suggested a variation: a five-mile critical radius and a wait of at least 15 minutes after the last lightning event.10Earth Networks. The Ultimate Lightning Guide for Airport Operations In practice, most major terminals halt ground operations when a strike occurs within five miles and resume 15 minutes after the last detected strike.12Flight Safety Foundation. Ground Strike The International Air Transport Association suggests a different threshold: alerts at five miles, stopping operations at three. A survey cited in industry research found 54 percent of respondents stopping ground operations at five miles, others at three, with critical-distance thresholds across stakeholders ranging from three to six miles and waiting periods from six to 30 minutes.13OpenSky UCAR. Lightning Ramp Closures and Airport Operations
OSHA supplies the enforceable floor. Under Section 5(a)(1) of the Occupational Safety and Health Act of 1970, employers must provide a workplace free from recognized hazards likely to cause death or serious harm. Lightning on a ramp qualifies. OSHA guidance calls for a written emergency action plan with a lightning-safety protocol covering criteria for suspending and resuming outdoor work, identification of safe shelter, and enough warning time for all workers to reach it. OSHA’s factsheet states that workers should remain in shelter for at least 30 minutes after the last sound of thunder, more conservative than the 15-minute figure many airports use. Acceptable shelter means a fully enclosed building with electrical wiring and plumbing, or as a fallback, a hard-topped metal vehicle with windows closed.14OSHA. Lightning Safety When Working Outdoors
The jurisdictional line between OSHA and the FAA for ground personnel is resolved case by case: OSHA retains authority unless the FAA has formally exercised its own statutory authority over the specific working condition, and the two agencies’ existing memorandums of understanding cover flight and cabin crews but not ground workers.14OSHA. Lightning Safety When Working Outdoors
What the FAA Does Control on the Ground
The FAA sets lightning-protection standards for its own facilities and equipment through FAA-STD-019, with version “e” published in October 2017. The standard sets requirements for lightning protection, transient protection, grounding, bonding, shielding, and electrostatic-discharge control for new facilities, modifications to existing ones, and new equipment used in the National Airspace System.15U.S. DOT ROSAP. FAA-STD-019e Lightning and Transient Protection, Grounding, Bonding, and Shielding Requirements After a thunderstorm passes, FAA regulations require special inspections of runways, taxiways, and ramps before they can be cleared for normal use.12Flight Safety Foundation. Ground Strike
The FAA also mandates how lightning and thunderstorms are observed and reported by aviation weather personnel. FAA Order JO 7900.5E, effective January 15, 2020, prescribes procedures for surface weather observations across the National Airspace System, including sections on observing and reporting thunderstorms and lightning, coding lightning type and frequency, and recording the beginning and ending times of thunderstorm activity. A Special Aviation Weather Report is required whenever a thunderstorm begins or ends at a reporting station.16FAA. FAA Order JO 7900.5E – Surface Weather Observing17FAA. Aeronautical Information Manual – Chapter 7, Section 1 Those reports feed into the SIGMETs, Convective SIGMETs, AIRMETs, and Center Weather Advisories pilots and dispatchers rely on to plan around hazardous weather.
When storms affect major airports, the FAA’s Air Traffic Control System Command Center coordinates traffic flow. Its tools include Ground Delay Programs (assigning delayed departure times to flights bound for an affected airport), Ground Stops (temporarily halting all departures to a destination), and Airspace Flow Programs (controlling traffic through constrained corridors using assigned departure-clearance times). The FAA also activates Severe Weather Avoidance Plans to reroute traffic around dangerous airspace, and may use pre-coordinated structured routes or low-altitude routing to keep planes moving when standard paths are blocked.18NBAA. Glossary of Traffic Flow Management Terms
Put the pieces together and the picture is consistent. Where the FAA has direct authority, over aircraft design and certification, its own facilities, weather reporting, and the flow of air traffic, the rules are specific and mandatory. Where the hazard falls on ground crews standing on a ramp, federal aviation law goes quiet, and the applicable rules come from the employer’s playbook and OSHA’s general-duty clause.