Browse Topic: Lightning protection

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Standardized composite training programAIR6671 (Current)11/26/2025
SAE CACRC has produced several standards, each representing the best-practice, recommended minimum training syllabus for the aforementioned target groups. The purpose of this document is to promote the use of these SAE standards, particularly for developing training programs for employee training, qualification in airlines and maintenance organizations, and as reference in regulatory guidance material. It summarizes, as a quick reference, the content of each training document and its relation to and interaction with other training documents. Thereby it allows users to select the appropriate training documents and syllabi to establish a comprehensive, sequential training program build-up customized to the specific needs of the aforementioned functions (see figure). This document does not intend to introduce new training content/syllabus.
AMS CACRC Commercial Aircraft Composite Repair Committee
Aerospace - Lightning Effects on Hydraulic Transport Elements on AircraftAIR6185A (Current)11/26/2025

This SAE Aerospace Information Report (AIR) describes hydraulic system design and installation to minimize the effects of lightning, especially when the aircraft structure is composite. Techniques for effective electrical bonding, hydraulic system lightning protection, and lightning protection verification techniques are discussed.

My new committee for commercial aircrafts
Status and Way Forward on Rotorcraft Lightning ProtectionF-0076-2020-1634510/5/2020
This paper provides an overview of the state of art on the lightning regulation and the means of compliance for lightning certification, based on both the simulation technics and the testing methods. Usual lightning protection solutions at helicopter level to fulfill lightning requirements are discussed, as well as advanced approaches used by Airbus Helicopters to minimize the weight penalty of the lightning protection, especially by a large use of the simulation for the optimization of both the indirect effects (LIE) and the lightning direct effects (LDE). Some perspectives are highlighted concerning the development of new lightning protection devices to withstand the higher induced currents coupled on equipment items installed in full composite airframe helicopters (H/C), and how the lightning may be avoided on future platforms like the emergent flying urban taxis.
Zehar, Sonia, Meyer, Marc, Tagliana, Bernard
Electrically Non-Conductive Ladder Fall ProtectionTBMG-361943/1/2020
NASA’s Kennedy Space Center developed an electrically non-conductive ladder fall protection system for the Launch Complex (LC) 39B lightning towers. The towers include a 100-foot fiberglass mast at the top of the tower structure. The fiberglass masts insulate the metallic tower structure from the lightning strike protection system that is housed at the top of the fiberglass masts.
S400 Copper Media Interface Characteristics Over Extended DistancesAS5643/1A (Current)7/9/2019
This SAE Aerospace Standard (AS) establishes guidelines for the use of IEEE-1394-2008 Beta (formerly IEEE-1394b) as a data bus network in military and aerospace vehicles. It encompasses the data bus cable and its interface electronics for a system utilizing S400 over copper medium over extended lengths. This document contains extensions/restrictions to “off-the-shelf” IEEE-1394 standards, and assumes that the reader already has a working knowledge of IEEE-1394. This document does not identify specific environmental requirements (electromagnetic compatibility, temperature, vibration, etc.); such requirements will be vehicle-specific and even LRU-specific. However, the hardware requirements and examples contained herein do address many of the environmental conditions that military and aerospace vehicles may experience. One should refer to the appropriate sections of MIL-STD-461E for their particular LRU, and utilize handbooks such as MIL-HDBK-454A and MIL-HDBK-5400 for guidance. This document is referred to as a “slash sheet” and accompanies the AS5643B base standard.
AS-1A Avionic Networks Committee
Streamlining EMC Solutions for Avionics Interfaces19AERP02_042/1/2019
Lightning strikes to jet airliners are common - about once every 1000 flight hours. The DO-160G standard, Environmental Conditions and Test Procedures for Airborne Equipment, is a standard for the environmental testing of avionics hardware. Many airplane manufacturers specify DO-160G Section 22, lightning induced transient susceptibility, as a requirement for critical systems like guidance, radars, communications, engine control, and heat and air controls. Aircraft fuselage, wing and tail flight controls, wing tips, fin tips, engine nacelles, and landing gear are the areas most likely to be hit by lightning strikes. Modern aircraft are designed with fly by wire systems for flight controls. Fly by wire means that inputs from either flight control computers or pilot manual inputs are transmitted electrically to a servomotor, which controls flight control actuators. Communication interfaces for these flight control systems can be implemented on an RS-485 physical layer. Communication interfaces for aircraft engine management control can also be implemented with an RS-485 physical layer. The full authority digital engine control (FADEC) systems installed on aircraft engines are responsible for monitoring temperatures, pressure, and fuel flow, among other parameters.
Streamlining EMC Solutions for Avionics InterfacesTBMG-337732/1/2019
Lightning strikes to jet airliners are common - about once every 1000 flight hours. The DO-160G standard, Environmental Conditions and Test Procedures for Airborne Equipment, is a standard for the environmental testing of avionics hardware. Many airplane manufacturers specify DO-160G Section 22, lightning induced transient susceptibility, as a requirement for critical systems like guidance, radars, communications, engine control, and heat and air controls. Aircraft fuselage, wing and tail flight controls, wing tips, fin tips, engine nacelles, and landing gear are the areas most likely to be hit by lightning strikes.
Aircraft Lightning ZoneARP5414B (Current)12/5/2018
This SAE Aerospace Recommended Practice (ARP) defines lightning strike zones and provides guidelines for locating them on particular aircraft, together with examples. The zone definitions and location guidelines described herein are applicable to Parts 23, 25, 27, and 29 aircraft. The zone location guidelines and examples are representative of in-flight lightning exposures.
AE-2 Lightning Committee
Sequential/Simultaneous Multi-Metallized Nanocomposites (S2M2N)TBMG-2798712/1/2017
NASA Langley Research Center has developed a method to create Sequential/Simultaneous Multi-Metallized Nanocomposites (S2M2N) via supercritical fluid (SCF) sequential or simultaneous multi-metal infusion. The SCF infusion process provides deep impregnation of metal nanoparticles into a variety of materials, including those with challenging topographies and complex structures. The resulting multi-metallized nanocomposites can possess high electrical conductivity, permittivity, permeability, wear resistance/anti-penetrant, and radiation shielding along with high toughness.
Thermoplastic Fuselage DemonstratorTBMG-2766110/1/2017
Porcher Industries Badinières, France +33 (0)4 74 43 10 10
Electromagnetic Compatibility and Interference - Design Methodology, Challenges and Guidelines for Avionics Product and Systems2017-01-21189/19/2017
Avionics industry is moving towards more electric & lightweight aircrafts. Electromagnetic effects becomes significantly challenging as materials starts moving towards composite type. Traditional methods for controlling EMC will not be sufficient. This shift increases the complexity of in-flight hardware elements for EMI/EMC control. This paper discusses the need for EMI/EMC Control and brings out the analysis & applicability of various EMI/EMC standards in aerospace, commercial and industrial electronic products, provides comparative study with respect to levels. The study include various sections of DO-160 and applicable guidelines for controlling EMI/EMC with respect to LRU (Line Replaceable Unit) & wire/cable harnesses. Also presents guidelines with respect to shielding of components, selection of components, grounding schemes, filter topologies and layout considerations. It provides comparative study made for different filters, good layout examples, generic simulation examples and lessons learnt from the failures. An attempt is made to propose the design methodology to be adapted for successful design for Electromagnetic effects. This paper puts forth the various challenges like size constraints, isolation requirements, component shielding, cost of EMI filters, weight, layout of- high speed & mixed signal boards and interference due to new wireless devices getting added on aircraft. The paper makes an effort to provide the possible mitigation methods for the same. Implementation methods like H-Field dominance, smaller loop area, EMI gaskets, shielding of cables and magnetic field control have been discussed. Various pain points with respect to qualification and reusability approach have been discussed. Probable solutions to overcome those have been outlined in this paper.
Vadgaonkar, Prashant S, banik, Diptar
Electric Field Quantitative Measurement System and MethodTBMG-261391/1/2017
NASA Langley Research Center’s Electric Field Imaging (EFI) system is the only noncontact method capable of quantitatively measuring the magnitude and direction of electrostatic fields in near- and far-field applications. Based on low-cost, commercially available components, the EFI system uses measurement of very-low-current, human-safe electric fields to construct a three-dimensional image of objects and people based on their dielectric properties. This platform technology, originally developed for measurement of the efficacy of electrical shielding around cables, could be optimized for a variety of applications, including medical imaging, security and detection, weather and natural disaster prediction, and nondestructive evaluation of composites and insulators. The EFI system has the potential to offer a lower-cost, portable, and safer alternative to the imaging systems currently used in these applications.
Lightning Protection and Detection SystemTBMG-261551/1/2017
NASA’s Langley Research Center has developed a sensor technology for structural health monitoring on composite aircraft surfaces. When conventional aircraft are struck by lightning, the result can range from no damage to serious damage requiring extensive repairs that can take the airplane out of service for an extended period of time. The SansEC technology is a proven wireless sensing platform capable of measuring the electrical impedance of physical matter in proximity to the sensor based on a change in its resonance response. The sensor also exhibits a unique characteristic to disperse the lightning strike current to help mitigate lightning damage. In this application, an array of SansEC sensors will cover a selective area of the aircraft surface, providing both mitigation and damage sensing.
Aerospace & Defense Technology: June 201616AERP066/1/2016
Digital Design Tools Simulating Thermal Expansion in Composites with Expanded Metal Foil for Lightning Protection Rugged Computing Designing VME Power Systems with Standard Modules Optical Sensors Optical Ice Sensors for UAVs Rotorcraft Technology Rotorcraft Icing Computational Tool Development RF & Microwave Technology Curled RF MEMS Switches for On-Chip Design: Design Software Supports BAE System's Mixed-Signal Chip Design
Aerospace - Lightning Effects on Hydraulic Transport Elements on AircraftAIR6185 (Historical)8/28/2015
This SAE Aerospace Information Report (AIR) describes hydraulic system design and installation to minimize the effects of lightning, especially when the aircraft structure is composite. Techniques for effective electrical bonding, hydraulic system lightning protection, and lightning protection verification techniques are discussed.
A-6A1 Commercial Aircraft Committee
NASA Launch Pads Protected Against Lightning-Induced Power SurgesTBMG-2066810/1/2014
Circuit protection components Littelfuse Chicago, IL 773-628-1000
Aerospace & Defense Technology: February 201414AERP022/3/2014
Thermal simulation and testing of expanded metal foils for lightning protection With the implementation of major aircraft structures fabricated from carbon fiber reinforced plastic materials, lightning protection has become a more complicated issue for designers and engineers to solve. Electronics take charge Digital controls are handling more engine control tasks on a wider range of aircraft.
Aerospace - Testing of Electromechanical Actuators, General Guidelines ForARP5724 (Current)10/4/2013
This document provides an overview of the tests, and issues related to testing, that are unique to Electromechanical Actuators (EMAs). The tests, and issues documented, are not necessarily all-inclusive. This document discusses both the tests applicable to EMAs and the test methodologies to accomplish the test objectives. EMAs may be used in a wide variety of applications such as utility, secondary flight controls and primary flight controls, in a wide variety of markets including manned and unmanned civil and military aircraft, small missile fin and thrust vector control applications up to high powered utility and flight controls. EMAs may also have either a rotary or a linear output, be servo controlled or use simple open loop point-to-point or other control topologies. As such this document covers a wide range of potential applications, the application of any given test requirement is determined by the application and the user. This document attempts to provide basic guidance on which tests should be considered for various applications. This document also lists tests that are not unique to EMAs, but are still applicable to EMAs. In these instances a discussion of such tests is not contained in this document, and as applicable, the reader may reference the appropriate documents as indicated in the text. While many EMA configurations include digital power drive electronics (PDE), the specific tests required for the electronic hardware, software, or firmware are outside the scope of this document.
A-6B3 Electro-Mechanical Actuation Committee
Aircraft Structure Paint Thickness and Lightning Swept Stroke Damages2013-01-21359/17/2013
During its flight an aircraft can be struck by lightning and the induced high current will require a highly conductive airframe skin structure in order for it to propagate through with minimum damage. However an aircraft skin is generally coated with paint and the airframer does not always have control on the paint thickness. Paint thickness generates heightened concerns for lightning strike on aircraft, mainly because most of coatings dedicated to that purpose are non-conductive. Using insulating material or non-conductive coating with certain thickness may contribute to or increase damage inflicted by the swept stroke lightning energy, even on metallic structures Due to its high relative permittivity, a non-conductive paint or coating on a fuselage skin surface will contribute to slow down the lightning current propagation through structure. With this comes the risk of increasing heat that will favor structural damage and possible melt through. The correlation between paint thickness, lightning dwell time, and aircraft skin thickness are all contributing factors in lightning swept stroke damage in aircraft lightning Zone 2A. Paint thickness is not always under direct control of the manufacturer and the maximum paint thickness that could safely be applied on an aircraft skin with very low risk of puncture due to lightning is still a controversial matter. This paper introduces the analysis and investigation performed by the Bombardier Aerospace Core Engineering Electromagnetics team through several test campaigns.
Moupfouma, Fidele
Thermal Simulation and Testing of Expanded Metal Foils Used for Lightning Protection of Composite Aircraft Structures2013-01-21329/17/2013
Since the 1960's, lightning protection of aircraft has been an important design aspect, a concern for the flying public, aircraft manufacturers and the Federal Aviation Administration (FAA). With the implementation of major aircraft structures fabricated from carbon fiber reinforced plastic (CFRP) materials, lightning protection has become a more complicated issue to solve. One widely used material for lightning strike protection of CFRP structures within the aerospace industry is expanded metal foil (EMF). EMF is currently used in both military and commercial passenger aircraft. An issue that has historically been an area of concern with EMF is micro cracking of paint on the composite structure which can result in corrosion of the metal foil and subsequent loss of conductivity. This paper addresses the issues of stress and displacement in the composite structure layup which contribute to paint cracking caused by aircraft thermal cycling. The analysis of EMF by computer modeling is made using commercially available COMSOL Multiphysics software that is supported by data from limited experimental testing. Variables that are explored include width, height, mesh aspect ratio, weight, composition and surface layup structure. Horizontal displacement profiles parallel to the surface are utilized for performance comparisons.
Morgan, Jeffrey
Electromagnetic Protection Hazards on Composite versus Metallic Aircraft2013-01-21579/17/2013
The lightning represents a fundamental threat to the proper operation of aircraft systems. For aircraft protection, Electromagnetic Compatibility requires conductive structure that will provide among all, electromagnetic shielding and protection from HIRF and atmospheric electricity threat. The interaction of lightning with aircraft structure, and the coupling of induced energy with harnesses and systems inside the airframe, is a complex subject mainly for composite aircraft. The immunity of systems is governed by their susceptibility to radiated or conducted electromagnetic energy. The driving mechanism of such susceptibility to lightning energy is the exposure to the changing magnetic field inside the aircraft and IR voltage produced by the flow of current through the structural resistance of the aircraft. The amplitude of such magnetic field and IR voltage is related to the shielding effectiveness of the aircraft skin (wiremesh, composite conductivity). However, it is also known that copper wiremesh does not provide adequate protection from magnetic field, even though it is needed for lightning current dissipation and the reduction of the heat that could damage the structure, following a lightning strike. The protection from magnetic field on composite aircraft can be provided by ferromagnetic material that nevertheless appears too heavy for covering the whole aircraft fuselage. Thus the need for R&D activities on nano technologies for solutions providing good magnetic shielding effectiveness without impacting aircraft weight. In the scope of aircraft Electromagnetic Protection and aircraft Safety activities, Bombardier Core Engineering is conducting R&D work on aircraft structure protection from lightning, and collaborating with University of Québec at Trois-Rivières (UQTR). This paper highlights the impact of magnetic field due to lightning on composite aircraft.
Moupfouma, Fidele, Klim, Zdzislaw, Skorek, Adam
Electromagnetic Compatibility (EMC) System Design ChecklistAIR1221 (Current)2/24/2013
This checklist is to be used by project personnel to assure that factors required for adequate system electromagnetic compatibility are considered and incorporated into a program. It provides a ready reference of EMC management and documentation requirements for a particular program from preproposal thru acquisition. When considered with individual equipments comprising the system and the electromagnetic operational environment in which the system will operate, the checklist will aid in the preparation of an EMC analysis. The analysis will facilitate the development of system-dependent EMC criteria and detailed system, subsystem, and equipment design requirements ensuring electromagnetic compatibility.
AE-4 Electromagnetic Compatibility (EMC) Committee
Lightning Requirements: Where They Come From and How to Analyze Their Impact2012-01-214910/22/2012
Many avionics and aircraft equipment manufacturers use DO-160 [Ref. 1] Section 22 to test their equipment for indirect effects of lightning without understanding why they are testing to specific values. Many aircraft manufacturers struggle with determining the level of indirect lightning that will be acceptable for their vehicle and what level of requirements they need to pass down to the avionics and aircraft equipment manufacturers. Organizations like SAE and RTCA, Inc. work to collect data on lightning and spend countless hours assimilating the information and developing documents to help engineers use the information. They struggle with knowing what data is pertinent and how it will be received and used by the engineering community. This paper walks through the process of how the lightning levels are developed, how the levels get selected for a particular application, and how to use this information to perform an analysis of the survivability of a specific circuit in an electronic system. This paper will provide an introduction of the process that each of the three primary levels of experts use to contribute to the overall design of flight hardware that is safe to fly in a lightning environment. The purpose of this paper is to provide information to all three levels of experts about how their data is being used and what information is useful for carrying on the design process.
Harrington, James
Software Creates and Analyzes Lightning Protection Solutions for Wind TurbinesTBMG-146589/1/2012
Highvoltage.dk is a Danish consulting engineering firm with expertise in lightning protection and high-voltage engineering. The company, founded in 2005, tackles complex problems such as general high-voltage design engineering for the power industry, lightning protection concepts and findings for wind turbines, and high-voltage material tests. The engineers at Highvoltage.dk are experienced users of numerical analysis tools to simulate magnetic and electric fields, current distribution, and lightning attachment points.
An Advanced Circuit Protection Approach for RF InterfacesTBMG-1228812/1/2011
One aspect that sets circuit protection for radio frequency (RF) apart from other types of applications is the range of frequencies in which RF circuits operate. With abbreviated clock cycles, the transition time of the data leaves little room for error. Transitions must be clean and reliable to ensure the integrity of the data and interface. Circuit protection characteristics such as capacitance become important in terms of their effect on these high-frequency signals and it often complicates the design.
Data Acquisition System Monitors Lightning StrikesTBMG-1191511/1/2011
Genesis HighSpeed data acquisition system and Perception software HBM Marlboro, MA 508-624-4500 www.hbm.com
Probability Assessment of the Fuel Tank Structural Feature Failures2011-01-251810/18/2011
The paper provides an approach to establish compliance with current regulatory standards applicable to lightning protection of the fuel tank structure for Non-Fault Tolerant Feature Failures (NFTFF) through a numerical probability assessment. The proposed procedure is using the criteria defined in the FAA Policy Guidance for fuel tank structural lightning protection and is aligned with the regulatory path described as petitioning for an exemption. Failure modes of structural components for which fault tolerance has been shown to be impractical need to be addressed and the overall likelihood of fuel vapour ignition due to these failure modes must be shown to be extremely improbable. In order to accomplish this, the quantitative assessment of the overall probability of fuel vapour ignition is performed, along with all relevant data to support the probabilities determined for the purpose of this analysis. The relevant non-fault tolerant structural design areas that may contribute to ignition sources inside the fuel tank when a failure occurs must be identified. Each type of non-fault tolerant feature failure must be assessed and the result has to be summed. The set of the potential failure modes regardless of the probability of occurrence is established by performing a complete wing tank survey in pertinent areas related to fuel tank lightning protection. If the failure assessment results in demonstrating that the design is free from ignition sources after an assessment of relevant single failure conditions, then the design is considered to be fault tolerant. If not, then further analysis is required per numerical probability assessment for the Non-Fault Tolerant Feature Failures. The subset of NFTFFs must be defined and the numerical probability assessment has to be performed. The purpose of the assessment is to substantiate that the probability of failures associated with non-fault tolerant features that might lead to a fuel tank explosion belongs to the extremely improbable category. This paper intends to provide a practical method for the fuel tank structure numerical assessment along with a real-life example illustrating a potential application.
Klim, Zdzislaw H., Skorek, Adam W.
Lightning Monitoring System Helps Protect ShuttleTBMG-79275/1/2010
Genesis HighSpeed data acquisition products HBM Marlborough, MA 800-578-4260 www.hbm.com/highspeed
Aerospace – Test Methodology for Electrohydrostatic ActuatorsARP5879 (Historical)4/28/2010
This document provides an overview of the tests and issues related to testing that are unique to Electrohydrostatic Actuators (EHAs). An EHA incorporates a linear or rotary hydraulic actuator and a variable speed, reversible electric servomotor driving a fixed displacement hydraulic pump for actuator control, and associated power drive electronics. The tests and issues documented are not necessarily all-inclusive. This document discusses both, the tests applicable to EHAs and the test methodologies to accomplish the test objectives. This document also lists tests that are not unique to EHAs, but are still applicable to EHAs. In these instances a discussion of such tests is not contained in this document, and as applicable, the reader may reference ARP1281 (Actuators: Aircraft Flight Controls, Power Operated, Hydraulic, General Specification For), which addresses test issues applicable to electrohydraulic flight control servoactuators. In the discussion of the tests and test methodologies contained in this document, numerical definition or specification of the test parameters to be imposed or measured is not included. These definitions or specifications should be developed to conform to the requirements of the applicable EHA technical specification document, considering the usual influencing factors such as instrumentation accuracy, test temperature, etc.
A-6B2 Electrohydrostatic Actuation Committee
MIL-STD-1553 Physical Layer for Time-Triggered Networks2009-01-314711/10/2009
Time Triggered networking technologies such as TTP (Time Triggered Protocol) are beginning to be used in critical aerospace applications such as flight controls. While TTP provides stringent specifications for determinism and fault tolerance, it does not define a physical layer. TTP's “de facto” physical layer, RS-485, includes shortcomings in a number of areas. These include a relatively low minimum transmitter voltage, low receiver threshold, along with a lack of specificity in a number of areas. The latter include bus signal levels, transmitter zero-crossing distortion and receiver zero-crossing tolerance, isolation method, terminal output noise, common mode and noise rejection, and input impedance. MIL-STD-1553, which has been deployed in flight and mission critical military applications for decades, defines a highly proven and robust physical layer. This paper presents MIL-STD-1553's physical layer as a candidate for use with TTP.
Glass, Mike
Aircraft Lightning Direct Effects CertificationARP5577 (Current)3/26/2008
This document provides guidance for a means of showing compliance with regulations for protection against lightning direct effects for aircraft of conventional design, as well as for those involving advanced composite structures or other new technologies. This guidance also applies to those aspects of aircraft systems and components not addressed in the regulations covering the protection of electrical/electronic systems (for example, FAR/JAR xx.1316) or fuel systems (for example, xx.954). The guidance provided in this document applies to initial designs as well as modifications.
AE-2 Lightning Committee
Flight Line Grounding and Bonding of AircraftARP4043B (Current)10/9/2007
This ARP provides the rationale and theory of charges being present on aircraft while on the ground. The necessary implementation of safety practices are explained and defined.
AE-4 Electromagnetic Compatibility (EMC) Committee
Certification of Aircraft Electrical/Electronic Systems for the Indirect Effects of LightningARP5413A (Current)3/21/2007
AE-2 Lightning Committee
Characterization of Aircraft Electrostatic Charging/Discharging Effects and the Influence of Aircraft Skin Conductivity2006-01-15074/3/2006
During an aircraft flight, water droplets, snow or precipitation will impact the fuselage and the wing surfaces, and develop static charges on the structure. Because of composite materials, those charging particles can produce potential differences between surfaces of different aircraft zones. The transients generated by the discharge can couple into onboard electronic/electrical systems and cause no found faults or upsets. Electrostatic Discharge (ESD) phenomenon resulting from corona effect can generate very high electric field that can couple with wiring bundles and generate communications disruption during flight. ESD effects have to be properly addressed during an aircraft design, as are Lightning and HIRF. This paper presents some theoretical considerations and experimental data based on full aircraft ESD ground tests at Bombardier facilities in Mirabel (Montreal).
Moupfouma, Fidele, Bae, Nami
Certification of Aircraft Electrical/Electronic Systems for the Indirect Effects of LightningARP5413 (Historical)3/24/2006
This SAE Aerospace Recommended Practice (ARP) provides guidance for a means of showing compliance with the regulations for hazards caused by the lightning environment to electrical/electronic systems installed either on or within aircraft. Equipment hazards addressed include those due to indirect effects on equipment and its associated wiring that is mounted on the aircraft exterior as well as indirect effects on equipment and its associated wiring located within the aircraft interior. This document applies to new aircraft and equipment designs, modifications of existing aircraft or equipment, and applications of existing (off the shelf) equipment on new aircraft. NOTE: This ARP does not address direct effects such as burning, eroding, blasting, of aircraft structure nor does it address fuel ignition hazards (see related reading material in 2.3 of this document). This ARP does not address lightning zoning methods or lightning test requirements, methods, and techniques. Coverings (fairing, skin, cowl, etc.) should normally prevent direct attachment of the lightning channel to underlying system components. However, if a direct lightning strike attachment to a system component can occur, a complete evaluation of both direct and indirect effects will be necessary. It should be noted that electrical/electronic systems or components are sometimes exposed to lightning currents directly conducted from the aircraft exterior, as may happen when an antenna is struck and a portion of lightning current flows in its cable. Care should be taken to identify any such possibilities and either eliminate these situations by design modifications, or address them in the certification plan. No further discussion of these situations is included in this ARP.
AE-2 Lightning Committee
Study of Lightning Effects in Aircraft2004-01-323611/16/2004
Lightning is a high voltage and high current phenomenon and it originates by build up of electrical charge in the air or, more commonly, in clouds. It is constituted of an electric current peak of short duration (0,5 ms) and high intensity (200 kA), followed by a low intensity (400 A) but high duration (1s) periods. The lightning effects in aircraft can be divided in two groups: direct effects (physical effects such as melting, rupture, damage of surfaces and structures due to conduction of lightning current or high power magnetic force) and indirect effects (electromagnetic fields generating levels of transient voltage and current on interconnecting wiring and cable leads within the equipment circuits eventually damaging internal components). The objective of this work is present and discuss the lightning effects and, subsequently, possible lightning protection applied to aircrafts by establishing adequate conductive paths for lightning current to flow through the aircraft structure and skin, without cause catastrophic damage, between possible lightning entry and exit points and control of all of the effects due to electromagnetic fields with no hazard to flight safety and operational reliability.
Baldacim, Sandro Aparecido, Cristofani, Nivaldo, Santos, Carlos do Nascimento, Lautenschlager, José Rui
Responses of Lightning Rods to Nearby Lightning2001-01-29079/11/2001
In an effort to determine the effectiveness of the sharp tipped lightning rods widely used in the U.S., we carried out a competition between sharp and blunt rods to determine which was preferentially struck by lightning. Over the past eight years, 12 blunt rods participated in cloud-to-ground discharges while none of the nearby rods with sharp tips were struck. Our analysis suggests that the emissions of point discharges from the tips of sharp rods associated with the rapid decrease of the electric field strength around the tips combine to make sharp rods poorer receptors for lightning than are moderately blunt rods.
Moore, Charles B., Aulich, Graydon, Rison, William
Probabilities of Catastrophe in Lightning Hazard Assessments2001-01-28779/11/2001
The airworthiness certification authorities specify overall probability levels for catastrophic and less severe effects on aircraft and their occupants. In lightning standards concerning threat levels and zoning for lightning attachments we speak of high and low probabilities. But, despite the certification authority’s overall figure, only one attempt has been made to interpret what that figure means for lightning protection. That one attempt was made under the EC funded FULMEN programme to estimate the degree of accuracy needed in the process of aircraft lightning attachment zoning. Without some figures, how do we know how good our designs have to be. Furthermore, as the number of flight-safety critical systems on our aircraft increases, how does the probability of failure of each change to ensure the overall figure remains the same? There are many figures we do not have, because lightning is too unpredictable an event, because we have too few measurements of the “real” lightning that we are trying to protect against, and because we have too little knowledge of the science behind the whole range of phenomena involved., Despite that we can make some intelligent guesses or estimates, at least to understand where about we are. Such an analysis would be of benefit also in the debate on whether the external threat level is adequate as it is presently defined, in furthering the understanding of the need for fidelity in attachment zoning analysis, and in defining thoroughness necessary in assessing similarity between aircraft and their installations. In this paper an attempt will be made to assess these probabilities, and some of those “guestimates” will be laid out. It is hoped that this will start some discussion and hone both the numbers and the process to something of real use.
Jones, C. C. R., Rowse, D., Odam, G. A. M.
Small Shelters and Safety from Lightning2001-01-28969/11/2001
Small open shelters are common on athletic fields, golf courses, parks, roadside picnic areas, schoolyards, and elsewhere. Many of these shelters are built to protect against rain or sun, not lightning. What can be done to minimize risk/maximize safety for people inside them under direct and indirect lightning strike conditions? Although there is no such thing as a lightning-proof small outdoor shelter, a properly designed and installed lightning protection system may make a difference. Sometimes the difference is between life and death.
Kithil, Richard, Rakov, Vladimir
Waveform Comparisons Between Qualification Data and Aircraft Measurements2001-01-29179/11/2001
Lightning induced current and voltage pulses are defined in international standards as arising from three distinct coupling mechanisms: capacitive, inductive and resistive. These mechanisms at their simplest give rise to distinct characteristics in the induced wave-shapes relative to the lightning current pulse that caused them. It has long been the practice to decide from a particular induced wave-shape, which was the likely induction mechanism, and compare it in terms of peak amplitude only with the relevant qualification test waveform. This approach fails to take account of the fact that almost all induced waveforms are actually a sum of two or all of the coupling mechanisms, that the coupling is not simple but gives rise to much more complex wave-shapes than the qualification standards would imply, and that there are other critical parameters apart from the peak amplitude. It may also disguise the effect of possible building/rig resonances in test results. In this paper the authors argue that this simple approach is not enough and devise a set of norms encapsulating the properties of current and voltage waveforms in simple quantities that permit a comprehensive comparison between wave-shapes. The characterisation can be done in a standard spreadsheet program provided the two sets of data can be put into a digital form.
Jones, C. C. R., Powell, Shawn, Gallagher, Joe
Integral Lightning Strike Protection of CFC Fuel Tanks on Aircraft2001-01-29129/11/2001
The external structure of fast jet aircraft are now often constructed largely from Carbon Fibre Composites (CFC). Much of the external skins form part of fuel tanks. A lightning strike to a tank skin is likely to cause arcing and sparking at structural joints. This can lead to particles of molten metal or resin being injected into the fuel tanks along with hot gasses which presents a risk of fuel explosion. This paper describes lightning strike protection of CFC fuel tanks with emphasis on integral lightning strike protection and the protection of access panels. This integral protection is based on a network of copper strips co-bonded into the composite tank shell. The protection details, such as foil thickness and fastener installation details may be varied to suit the lightning strike threat. The details are specified in BAE SYSTEMS patents Ref. 1.
Pridham, Barry, Jaeger, Dieter, Schreiner, Manfred
Application of the Finite Difference Time Domain Code EMA3D to the Modeling of Indirect Lightning Effects in a Composite Panel and Wing Box2001-01-29119/11/2001
The Finite Difference Time Domain (FDTD) method (as implemented in the commercial software package EMA3D) is used to model indirect lightning effects in a composite three bladed panel and a composite wing-box. The analysis is compared with low level continuous wave (LLCW) tests performed in the Boeing Lightning Effects Laboratory. Measured data include transfer functions for currents induced on metal tubing interior to the three-bladed-panel and wing-box. The thin wire and thin plate formalisms provided in EMA3D are used to model the composite surfaces and metallic conductors such as pipes in the wing-box. The wing-box is simulated both with and without apertures. The modeling results showed excellent agreement with measurements over a broad frequency range demonstrating the usefulness of FDTD as a predictive tool for lightning frequencies.
Lenning, Frank E., Rimbey, Peter R.
The Development, Deployment, and Operation of an On-Line Lightning Monitoring System (OLMS) for Spacecraft Launch Support2001-01-29019/11/2001
The On-Line Lightning Monitoring System (OLMS) is designed to continuously detect and characterize the effects of lightning-induced electromagnetic transients at a number of spacecraft launch sites in the United States. The OLMS uses broadband sensors, installed at a number of preselected locations at the launch site, to simultaneously measure incident electromagnetic fields, as well as energy coupled to conductors, using a unique combination of analog and digital subsystems. The system allows users to assess the electromagnetic threat to sensitive electronic systems aboard spacecraft, thereby retesting systems only if necessary. All data from OLMS is available in real time and can be accessed by authorized users via the Internet using a standard web browser interface. At the International Conference on Lightning and Static Electricity in 1999 (ICOLSE ‘99), we described the ongoing design and development of OLMS. The system is now installed and fully operational at five launch sites. This follow-up paper describes the technical features of OLMS, its deployment and use, and examples of data collected to date.
Sechi, Paolo G., Adamo, Richard C.
Frequency Domain Analysis for the Prediction of Lightning Indirect Effects and Comparison to Measured Data from Two Composite Test Articles2001-01-29069/11/2001
A lightning indirect effects analysis of a conductor over graphite composite structure was performed using a frequency domain analysis. An internal Boeing analysis code, EM_Model, was used to predict and model test data from two graphite composite test articles. The first was a simple graphite panel with an aluminum tube placed at various heights above the panel. The aluminum tube is representative of either hydraulic or fuel lines, or cable bundle shields. The second test article was the outboard section of a graphite wing-box with two aluminum tubes internal to the structure. A series of access panels in the wing skin provided a source of aperture coupling in addition to the diffusion currents. Both tests made low level CW (LLCW) measurements of the tube transfer function and were compared to model results with good agreement.
Dabelstein, Donald
Lightning Protection: Experimental Approach and Solutions for Large Sensitive Systems - Example of a Nuclear Power Plant -2001-01-29229/11/2001
This document describes the unclassified part of the lightning protection studies for a video control system. The study was held during September 1994 at Cruas Nuclear Power Plant (F-07). Positive improvements were seen immediately and long term benefits have been reinforced by continued protection. The studies were conducted with a new EMC (Electromagnetic Compatibility) concept: “Zero Method”. This concept uses an accessible and easy process to control the industrial electromagnetic interference from radio, cellular phones and lightning effects. The adopted solutions improve personnel and facility safety and provide a cost effective solution.
Soleil, Daniel, Alcaras, Alain
Leader Characteristics in Natural and Altitude Triggered Lightning Discharges2001-01-28719/11/2001
Characteristics of the electric field changes produced by stepped and dart-stepped leaders in natural negative cloud-to-ground (CG) lightning discharges and stepped leaders in altitude triggered lightning discharges have been analyzed by using data from broadband slow antenna system with 0.08 μs time resolution in Guangzhou area, Southeastern China. It has been found that the characteristic parameters of leader pulses in artificially triggered lightning discharges are a little different from that in natural negative lightning discharges, although the discharge processes and statistic features of the pulses are similar in two cases.
Xiushu Qie, Qilin Zhang Ye Yu
The Numerical Simulation of the Effects of Lightning Current Arcs at the Attachment Point2001-01-28739/11/2001
The damages and destructions on materials at the attachment point of an lightning arc are mainly caused by thermal effects. Pressure effects and shock waves which occur due to the high temperatures are mostly the consequence of these thermal processes. The calculation and prediction of the heating processes lead to a better understanding of the damage mechanisms. This allows the assessment and the design of materials and lightning protection components. The paper presents calculations for different materials and a critical comparison with some laboratory measurements. Investigated materials are several metals (Cu, Al, steel) on the one hand and carbon fibre composite (CFC) on the other hand. These materials differ in their electrical and thermal material parameters and in their reactions to the lightning arc stress. It was the aim of the calculations to determine the development of temperature distribution up to critical temperatures.
Brocke, Ralph, Noack, Friedhelm, Reichert, Frank, Schoenau, Jens, Zischank, Wolfgang
Influence of the Rod Height and Lightning Polarity on the Protection Zone2001-01-28979/11/2001
Presented in this paper is a method to calculate the Franklin rod protection zone, through mathematical equations by considering the Franklin rod height and lightning stroke polarity impacts on striking distance[1]. The method was developed and analyzed for different cases with varied rod heights, and for positive and negative polarity. The calculated results of the protection zone were compared to the laboratory measured outcomes of several protected objects with varied heights.
Grzybowski, S.
On the Modelling of Field-to-line Coupling Inside a Lightning Struck-Aircraft2001-01-28919/11/2001
This paper discusses the features of different field-to-line coupling simulation models to be used for the transient analysis of the EM induced effects of the direct lightning interaction with aircraft. The choice of one model is suggested by the quasi-magnetostatic nature of the lightning interaction problems, which generate numerical inaccuracy in the calculation of the electric field solution inside the computational domain. It is demonstrated that the use of the field-to-line coupling model based on the use of the magnetic field components allows to avoid numerical inaccuracy.
Sarto, Maria Sabrina, Scarlatti, Alberto
NFPA-780 (1997) Standard for the Installation of Lightning Protection Systems: Transitioning from an Outdated Concept2001-01-29219/11/2001
The National Fire Protection Association NFPA-780 Standard for the Installation of Lightning Protection Systems is the de facto lightning protection document in the USA. Special interest groups seeking to force scientifically unsubstantiated air terminals into NFPA-780 have coerced under threat of litigation the NFPA Standards Council to withhold the Version 2000 Upgrade of NFPA-780. This present state of paralysis exists despite membership approval of the Version 2000 Upgrade in accord with all the NFPA by-laws. More recently the Standards Council publicized its intent to (perhaps) withdraw NFPA-780 entirely. As a consensus document NFPA-780 represents minimum protection standards and contains some errors and omissions. The purpose of this paper is to discuss some of the NFPA-780 (1997) shortcomings and to summarize other lightning protection documents already peer-reviewed and in the literature. These alternative lightning protection guidelines may assist the specifying architect and engineer.
Kithil, Richard
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