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
<p>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.</p>
My new committee for commercial aircrafts
Remotely Piloted Air SystemsTBMG-3788210/1/2020
General Atomics Aeronautical Systems, Inc. San Diego, CA 858-762-6700
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
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
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
Vadgaonkar, Prashant S, banik, Diptar
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.
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.
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
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
Moupfouma, Fidele
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
Moupfouma, Fidele, Klim, Zdzislaw, Skorek, Adam
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
Morgan, Jeffrey
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
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
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
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
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
Baldacim, Sandro Aparecido, Cristofani, Nivaldo, Santos, Carlos do Nascimento, Lautenschlager, José Rui
Analytical Tools for the Design and Verification of Safety Critical Control Systems2001-01-29389/11/2001
Safety critical real-time computer systems such as digital fly-by-wire aircraft are designed to be highly reliable, able to detect and recover from faults, and fail in a safe state even in harsh environments. This paper presents an analytical tool that is being developed to enhance the design and verification of safety critical systems. The tool is used to analyze the effect of standard error recovery systems on closed-loop flight control systems. In particular, this paper develops models and analyzes the stability effect of error recovery rollback, reset, and restart systems in digital control systems due to system functional upsets induced by multiple burst waveforms (MBW’s) during a lightning flash. A simple example will be used to illustrate one use for the tool: comparison of different recovery methodologies by determining the minimum interarrival spacing between MBW’s to maintain closed-loop stability.
González, Oscar R., Gray, W. Steven, Tejada, Arturo
Precipitation-Static (P-Static) Overview of Composite Aircraft2001-01-29339/11/2001
Aircraft charging due to p-static results from two atmospheric conditions: 1) the vehicle’s presence in a thunderstorm, and 2) the triboelectric charging (frictional) caused by neutral snow, rain, or dust particle bombardment of the vehicle frontal surface. Both charging mechanisms can lead to p-static interference by the following mechanisms of charge redistribution: 1) corona discharges from sharp-edged extremities, 2) streamer discharges on dielectric surfaces, and 3) arc over between electrically isolated or intermittently grounded metallic sections. Corona discharges have spectral energy primarily in the LF through HF region but can have potentially significant energy levels in the VHF/UHF bands. Streamer noise is caused by charge buildup on non-conductive vehicle frontal areas such as radomes and windshields. The spectral energy content of streamer discharges extends beyond the UHF band; but the noise amplitude is low and the potential for RF interference is only a threat if the
Thornell, Jerry W.
Aircraft Lightning Strike Indirect Effects Evaluation by Low Level Swept CW Testing2001-01-29299/11/2001
One of the tasks to show compliance with the relevant requirements for protection against the effects of lightning on an aircraft is to derive the so-called internal environment. Of the methods available to determine the transfer functions from the specified external lightning environment to the aircraft specific internal environment, low level swept CW testing offers benefits over the high level or low level pulse injection methods. The paper looks at the way an actual test was conducted on the EADS Airbus Advanced Technology Demonstrator (ATD) testbed aircraft, a VFW614 model. This aircraft has been heavily modified to fly with an Electronic Flight Control System EFCS. The test is performed to determine the Transient Control Levels (TCL) and establish the Equipment Transient Design Levels (ETDL) for the new equipment.
Spiller, Olaf
Indirect Lightning Prediction Codes2001-01-28939/11/2001
Codes have been written that allow designers to predict lightning indirect effects on aircraft wiring and structural elements. As a cost saving alternative to aircraft level testing, the codes will be used to calculate actual transient levels (ATL) on aircraft wiring with the purpose of verifying system lightning protection certification compliance by analysis. The code suite employs a CAD feature to enter the problem geometry. Additional user inputs include electrical characteristics of an airframe, excitation of the airframe with lightning attachments, and computation and display of the electrical response of any electrical member of the airframe versus time. The time series for an electrical response is calculated using inverse Laplace transforms of pole-zero terms fitted to the spectral response of the chosen element. In all cases tested to date, very few pole-zero terms are needed compared to the number of frequency samples required for the equivalent accuracy using standard
Nachamkin, Jack, Brigante, Joseph
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
Sechi, Paolo G., Adamo, Richard C.
Correlated Sub-microsecond E-field and High-Speed Image of the Natural Lightning Attachment Process2001-01-28829/11/2001
A correlated high-speed image and E-field observation of natural lightning attachment process on a time scale of sub-microsecond has been performed. In one of the observed events, downward stepped leader pulses can be clearly identified either in E-filed or optical signals. When the stepped leader approaches within about three hundred meters of ground, optical pulses begin to appear in the lowest 40 m channel section. These pulses have larger amplitude than the pulses from the downward stepped leader. It appears that these pulses are produced by an upward connecting leader. These facts suggest that the upward connecting leader is also stepped and it could produce even stronger pulses than the corresponding downward leader. The downward stepped leader has a velocity of about 4x106 m/s, while the upward leader has the velocity of about 1.7x106 m/s. The return stroke pulses observed in the E-field and in the optical signal agree well in time but differ in fine structures. A fast
Wang, D., Chen, M., Takagi, N., Watanabe, T.
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
Ignition Hazards from Intermittent Electrical Contacts2001-01-29139/11/2001
For conventional metallic aircraft lightning protection methodologies have generally been well established by years of flight experience. However, recent events have highlighted the need to take into account the effects of age or existing fault conditions. For lightning this could mean currents being conducted across unbonded couplings, across bond straps which make intermittent contact, or by debris or chafed wires bridging to fuel gauges and their wiring. The paper discusses the effects of transient currents flowing through intermittent contacts, and the levels at which such transients present a potential threat for fuel ignition. In the main this is a review of existing data, but supported by experimental studies which are just beginning at Culham. The work has been carried out under the European EM-Haz and the Culham Lightning Club programmes
Haigh, Stephen, Percival, John
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
Electrical Strength of Ultra-Long Air Gaps2001-01-28989/11/2001
Some experimental results on discharge development in ultra-long air gaps (breakdown voltages, parameters of the leader stage) are presented. The obtained data are compared to available data on breakdown of long air gaps under positive switching pulses with critical time-to-crest. Existing empirical and theoretical formulae for calculation of sparkover voltage of rod-to-plane air gaps are reviewed. Electrical strength of ultra-long air gaps is considered based on general analysis of physical processes in leader stage of spark discharge. The electrical strength has been thus expressed in the given paper via some characteristic stabilization electric field for each spatial scale. As predicted here, the electrical strength along the lightning development path may decrease down to 3÷10 kV/m.
Syssoev, Vladimir S., Shcherbakov, Yuri V.
A Comparison of the Prediction of Lightning Indirect Effects Using 2-D Analytical Tools with Measured Data from Two Composite Test Fixtures2001-01-29049/11/2001
A comparison was done of the prediction capabilities for lightning indirect effects of two two-dimensional (2-D) computer codes using two graphite structural test fixtures. The two codes evaluated were an internal Boeing Method-of-Moments code and a commercially available Boundary Element method code. The codes were compared against each other and against test data. The purpose was to evaluate the prediction capabilities of both codes for use in predicting lightning indirect effects on internal components of graphite structure. Since 2-D codes are much easier to use than 3-D codes, they could be widely used in trade studies and design evaluations for lightning indirect effects protection of composite aircraft. The first code, REDIST, is a Method-of-Moments code developed in the 1980’s for use on the B-2. The REDIST code has short run times and is somewhat easier to use than the second code that was investigated. The second code examined, Oersted, is a Boundary Element method code and
Melander, Barbara, Gibbs, John, Sojka, Richard
ALISDAR: An Automatic Lightning System Detection and Recording2001-01-29199/11/2001
In the framework of an EC (European Community) project EM-HAZ (Electromagnetic Hazard), an Automatic Lightning System Detection And Recording (ALISDAR) has been developed. Electrical and magnetic field measurements are the best way to characterize the lightning strike to aircraft. A finite difference time domain (FDTD) method is used to estimate the lightning current from E and H field measurements. The severity and the location of the lightning strike could be used to optimize the maintenance operations. The best location in terms of cost for the ALISDAR sensors is a dummy window. The validation of the ALISDAR system is planned through two laboratory experiments.
Lalande, P., Blanchet, P., Laroche, P., Gineste, P. N., Basso-Cochard, B., Flourens, F., Ulmann, A., Dimnet, P.
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
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.
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