Browse Topic: Lightning

Items (192)
Find
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
Lightning Strike Experiments and Their Direct Effects on Flax Fiber-Reinforced Polymer Panels for Rotorcraft ComponentsF-0080-2024-13075/7/2024
This paper experimentally investigates direct effects of lightning strikes on flax fiber-reinforced polymers. Highcurrent artificial lightning strikes are conducted on coupon level to evaluate thermo-mechanical damage and to quantify the sufficiency of copper wire mesh as lightning strike protection (LSP). The dataset shall also serve for verification of prospected numerical simulation. The natural fiber flax, as a sustainable source of composite reinforcement, has been demonstrated to be suitable for semi-structural parts of rotorcraft. However, its low electrical and thermal conductivity requires a functional LSP layer for aviation applications. The test panels are investigated regarding their material combination, stacking sequence and level of LSP. Results show that two as well as three layers of 72 g/m2 copper mesh are not sufficient to withstand the standardized lightning current component A waveform of 200 kA. The high induced currents and low capability of energy dissipation leads to electro-explosion of metal and transient mechanical forces from shock waves causing mechanical damage on the test panels. Back surface-velocities increase with higher peak currents and higher level of protection results in lower damage. It is shown that a stacking of copper wire mesh results in less arc root dispersion.
Gaugelhofer, Lukas, Yavrucuk, Ilkay, Hajek, Manfred, John, Jonas
ASSEMBLED COUPLING ENVELOPE, THREADLESS - FLEXIBLE, FIXED CAVITY, CURRENT CARRYING, SELF BONDING, ENVELOPE DIMENSIONSAS7511B (Current)12/22/2020
G-3, Aerospace Couplings, Fittings, Hose, Tubing Assemblies
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
Identification and Assessment of Damage to Composite Aircraft Structures Training DocumentAIR6825 (Current)8/3/2020
Individuals who complete the applicable modules aligned with this training document will be able to define the type of damage, define the extent of damage, determine if further inspection is required, evaluate the damage against published allowable damage limits, and provide accurate documentation of the damage. The intended outcome of the training is increased safety such that no aircraft is released with unknown damage and that the aircraft meets continued airworthiness requirements. The goal is to change the culture from damage discovery to damage reporting while also reducing or eliminating flight delays due to incorrect or insufficient information. Teaching levels have been assigned to the curriculum to define the knowledge, skills, and abilities graduates will need. Minimum hours of instruction have been provided to ensure adequate coverage of all subject matter including lecture and practical exercise. These minimums may be exceeded and may include an increase in the total number of training hours and/or increases in the teaching levels. The modules are intended to be a competency-based training approach. Each curriculum is a subpart of this document. Module 1 is the Composite Awareness curriculum, independent of the application. Module 2 is the Initial Inspection and Damage Mapping curriculum. Module 3 is the Special Inspection Tools curriculum. Module 4 is the Reporting, Recording, and Assessment curriculum. NOTE: While the modules in this document are technically interrelated, each module can be trained independently; modules may be selected as applicable to an operator’s or maintenance organization’s needs. The combination of the modules represents the applicable identification and assessment process for damage to composite aircraft structures (see Figure 1). Module 1 is prerequisite for attendance to the other modules. The contents of Module 1 may also be used for composite awareness training of a broader target audience, including line mechanics.
AMS CACRC Commercial Aircraft Composite Repair Committee
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.
Understanding the Impact of Standardized SAE Waveform Parameter Variation on Artificial Lightning Plasma, Specimen Loading, and Composite Material Damage01-13-01-00022/18/2020
Previous works have established strategies to model artificial test lightning plasma with specific waveform parameters and use the predicted plasma behavior to estimate test specimen damage. To date no computational works have quantified the influence of varying the waveform parameters on the predicted plasma behavior and resulting specimen damage. Herein test standard Waveform B has been modelled and the waveform parameters of “waveform peak,” “rise time,” and “time to reach the post-peak value” have been varied. The plasma and specimen behaviors have been modelled using the Finite Element (FE) method (a Magnetohydrodynamic FE multiphysics model for the plasma, a FE thermal-electric model for the specimen). For the test arrangements modelled herein, it has been found that “peak current” is the key parameter influencing plasma properties and specimen damage. A 10% increase in peak current magnitude (and resulting 21% increase in action integral) results in a 12% increase in plasma peak pressure, a 5% increase in specimen surface current density, and subsequently a 8.7% increase in thermal damage volume and a 15.2% increase in thermal damage depth. Overall action integral has the strongest correlation with four of the five considered damage measures. Peak current has the strongest correlation with the other damage measure.
Millen, Scott, Murphy, Adrian, Abdelal, Gasser, Catalanotti, Giuseppe
Hardening Lightweight Metal Foams with NanocoatingTBMG-358181/1/2020
Bones are strong and stable and can cope with loads almost as well as steel. But despite their strength, they are light enough to be easily moved by humans and animals. The secret lies in the combination of a hard, exterior shell that encases a porous lattice-like network of bone tissue in the interior of the bone. This structure saves on material and reduces weight.
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
Post Lightning Strike InspectionF-0075-2019-146635/13/2019
Inspecting an aircraft after a known or suspected lightning strike can be a tedious and subjective task. While aircraft technical manuals do provide conditional inspections following a lightning strike, these inspections tend to be broad in their approach and based solely on the presence of visual damage. This paper discusses the simple technique of tracing the lightning path through the aircraft by the use of an analog magnetometer to identify ferromagnetic parts that have been magnetized by the substantial electrical current of a lightning strike. While this technique is not novel, it is not often published as an inspection technique. Knowing the approximate path of the lightning can assist aircrews and maintainers in the identification of suspect parts that may require further inspection, repair and/or replacement thereby increasing safety and ensuring continued airworthiness of the aircraft.
Massa, Travis
X-Ray Study of Low-Density MaterialsTBMG-339033/1/2019
It's hard to get an X-ray image of low-density material like tissue between bones because X-rays just pass right through like sunlight through a window. Sandia studies myriads of low-density materials, from laminate layers in airplane wings to foams and epoxies that cushion parts. So they borrowed and refined a technique from the medical field, X-ray phase contrast imaging, to look inside the softer side of things. The technique measures not just the number of X-ray photons that get through the sample, as in conventional X-ray imaging, but also the phase of the X-rays after they pass through, offering a complete look at interfaces inside a structure.
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.
Plasma Generator Using Spiral ConductorsTBMG-337032/1/2019
NASA's Langley Research Center has developed a patented SansEC sensor technology for use in many different areas, including tall structures and wind turbines. 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 SansEC sensor also exhibits a unique characteristic to disperse the lightning strike current to help mitigate lightning damage. In a turbine blade application, an array of SansEC sensors will cover the surface area of the composite blade, providing both lightning mitigation and damage sensing. NASA Langley is seeking industrial partners/licensees to commercialize this technology. The research team at NASA Langley is available to assist with further development.
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
ASSEMBLED COUPLING ENVELOPE, THREADLESS - FLEXIBLE, FIXED CAVITY, CURRENT CARRYING, SELF BONDING, ENVELOPE DIMENSIONSAS7511A (Historical)4/18/2018
G-3, Aerospace Couplings, Fittings, Hose, Tubing Assemblies
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
ASSEMBLED COUPLING ENVELOPE, THREADLESS - FLEXIBLE, FIXED CAVITY, CURRENT CARRYING, SELF BONDING, ENVELOPE DIMENSIONSAS7511 (Historical)9/7/2017
G-3, Aerospace Couplings, Fittings, Hose, Tubing Assemblies
Rotorcraft Fastener Electrical Contact Analysis for Optimal Carbon Fiber Composite Lightning Strike ProtectionF-0073-2017-121585/9/2017
ABSTRACT In this paper we investigate the importance of electrical contact efficiency between fasteners and skin-level expanded metal mesh and how it influences lightning current energy transport. Since carbon fiber reinforced polymer composites (CFRPs) are electrically anisotropic and typically exhibit relatively low conductivities which are directionally distinct, aerospace manufacturers frequently use metallic foil layers or an expanded metal mesh on outer surfaces of composite structures for lightning strike protection. Due to irregular topology and associated micro-texture of machined holes in composites it is shown non-uniform interface surfaces between the fastener and composite layers reduces electrical continuity, thereby impeding current flow as a result of increased contact resistance levels. Furthermore, lightning strike experiments have indicated that metal mesh intimacy around the perimeter of the fastener head directly affects overall electromagnetic response of the rotorcrafts outer surface when subjected to lightning currents due to impedance modification of the electrical network. The effect of electrical continuity between the fastener head and mesh strand contact points is calculated using a Multiphysics model to demonstrate the effects on current load distribution and fusing lifetime of the individual strands. Additionally, total number of fastener-mesh strand contact points and cross sectional area of each strand are shown as being important parameters which ultimately determine the amount of lightning current efficiently transferred across the rotorcraft skin surface.
Liebscher, Andreas, Rizza, Gregory, Prachumsri, Wudhidham
Risks of Lightning to Automotive Occupants and Electrical/Electronic Systems2017-01-00613/28/2017
Lightning strikes on automobiles are usually rare, though they can be fatal to occupants and hazardous to electronic control systems. Vehicles’ metal bodies are normally considered to be an effective shield against lightning. Modern body designs, however, often have wide window openings, and plastic body parts have become popular. Lightning can enter the cabin of vehicles through their radio antennas. In the near future, automobiles may be integrated into the electric power grid, which will cause issues related to the smart grid and the vehicle-to-grid concept. Even today, electric vehicles (EVs) and plug-in hybrid vehicles (PHEVs) are charged at home or in parking lots. Such automobiles are no longer isolated from the power grid and thus are subject to electric surges caused by lightning strikes on the power grid. A charging system connected to an EV or PHEV should absorb the surge, but powerful lightning strikes can overwhelm the surge protection and intrude into the electric and electronic (E/E) systems of the vehicles, as often happens with household electrical equipment. This paper discusses the increasing risks of lightning to automotive occupants and E/E systems. To demonstrate the risk to vehicle systems, artificial lightning was generated by a 3 MV-impulse voltage source and supplied to a test vehicle. Arcing at the vehicle’s metal joints was then observed; the electronic system of the instrument panel was destroyed in the experiment. The induced surge voltage and lightning current in the metal body were both measured to determine the impact on the vehicle’s electronic systems. In order to develop a theoretical model for vehicle lightning, a NiCr metal box was also examined under artificial lightning conditions. In these experiments, neither the vehicle’s metal body nor the NiCr box shielded the lightning well. During lightning strikes, significant voltage differences were observed in the metals, and the vehicle body did not work as a common ground. The voltage difference also suggested the generation of an electromagnetic field in the vehicle cabin that can be harmful to vehicle systems.
Alkhteeb, Sultan A.M, Oho, Shigeru, Nagashima, Yuki, Nishimura, Seisuke, Shimizu, Hiroyuki
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.
A Suitable Platform for Storm Penetration, Risk Analysis for the SPA-10 Aircraft Modification2016-01-20439/20/2016
The SPA-10 project, sponsored by U.S. National Science Foundation, is to acquire and qualify a replacement for the retired T-28 “storm penetration” aircraft previously used to acquire meteorological data to enable understanding and modelling of mid-continent thunderstorms. The National Science Foundation selected the Fairchild A-10 (bailed from the U.S. Air Force) as the platform to be adapted to perform the storm penetration mission to altitudes of eleven kilometers, and funded Naval Postgraduate School’s Center for Interdisciplinary Remotely-Piloted Aircraft Studies (CIRPAS) as prime contractor. An expert panel conducted a review of the SPA-10 project in 2014 and recommended a risk analysis addressing hazards to the aircraft and pilots, such as icing, hail, turbulence and lightning. This paper presents the results of the risk analysis performed in response to this need, including recommended mitigations. In general the A-10 aircraft systems and structure were shown to be robust and suitable, reinforced by an operational plan for incremental exposure to the full force of the storm. A key challenge was obtaining the necessary information to resolve the expert panel’s concerns for a military aircraft designed in the 1970’s, with significant upgrades since, for a radically different mission. The support and assistance of the USAF and the engine manufacturer, General Electric was critical to this endeavor. The participation of the operator of the previous storm penetration T-28 aircraft, the South Dakota School of Mines and Technology, was a crucial source for understanding the mission and operational environment.
Millar, Richard C., Mazzuchi, Thomas, Jonsson, Haflidi
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
Dual-Use Structures: Composite Wing with Structural Antenna ApertureF-0072-2016-115525/17/2016
Many modern aircraft, including rotorcraft, require conformal antennas and fairings to reduce wind drag, ice accretion, lightning strikes, and impact damage. An innovative composite wing configuration with a structural Ultra High Frequency (UHF) antenna window "aperture" has been developed. The wing is based on variants of lightweight X-Cor® sandwich core technology for durability and damage tolerance, with tailored electromagnetic properties in the aperture region of the wing. This paper presents a brief introduction to helicopter wings, a summary of recent research at Boeing and Army leading to this design, and the development approach used for this project. Structural and electromagnetic analyses are provided, and measurement results of an early prototype are summarized. The emphasis of this paper is on the wing configuration details surrounding the antenna aperture. The approach can be replicated on almost any current or future aircraft or rotorcraft.
Tyrell, Stacey, Robeson, Mark, Kube, Courtney, McCarthy, Dennis, Lavin, Ronald
Lightweighting Focus for TE's Connectivity SolutionsTBMG-2313510/1/2015
TE Connectivity recently announced two new aerospace connectivity solutions that offer substantial weight savings: its COPALUM Lite sealed terminals and splices, and its Raychem INSTALITE lightweight braid system.
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
Fiber-Optic Sensor for Aircraft and Structure Lightning MeasurementTBMG-224297/1/2015
An optical-fiber sensor based on Faraday Effect was developed for measuring total lightning current. Designed for aircraft installation, it is lightweight, non-conducting, structure conforming, and is immune to electromagnetic interference, hysteresis, and saturation. It can also be used on windmills, lightning towers, and can help validate lightning detection network measurements.
Aircraft In Situ Validation of Hydrometeors and Icing Conditions Inferred by Ground-based NEXRAD Polarimetric Radar2015-01-21526/15/2015
MIT Lincoln Laboratory is tasked by the U.S. Federal Aviation Administration to investigate the use of the NEXRAD polarimetric radars* for the remote sensing of icing conditions hazardous to aircraft. A critical aspect of the investigation concerns validation that has relied upon commercial airline icing pilot reports and a dedicated campaign of in situ flights in winter storms. During the month of February in 2012 and 2013, the Convair-580 aircraft operated by the National Research Council of Canada was used for in situ validation of snowstorm characteristics under simultaneous observation by NEXRAD radars in Cleveland, Ohio and Buffalo, New York. The most anisotropic and easily distinguished winter targets to dual pol radar are ice crystals. Accordingly, laboratory diffusion chamber measurements in a tightly-controlled parameter space of temperature and humidity provide the linkage between shape and the expectation for the presence/absence of water saturation conditions necessary for icing hazard in situ. In agreement with the laboratory measurements pertaining to dendritic and hexagonal flat plate crystals, the aircraft measurements have verified the presence of supercooled water in mainly low concentrations coincident with regions showing layered anomalies of positive differential reflectivity (ZDR) by ground-based radar, otherwise known as +ZDR ‘bright bands’. Extreme values of ZDR (up to +8 dB) have also been found to be coincident with hexagonal flat plate crystals and intermittent supercooled water, also consistent with laboratory measurements. The icing conditions found with the anisotropic description are considered non-classical (condensation/collision-coalescence) and require the ascent of air and availability of ice nuclei. A modest ascent rate (<1 m/s) is needed for preservation of the anisotropic ice crystal shapes, making them identifiable to dual-pol radar. In the other limit of strong ascent (several m/s and greater), a vigorous riming process is present leading to graupel and hail, and with attendant radar reflectivity of 30 dBZ and greater. These rimed hydrometeors are also readily verified by dual pol hydrometeor classification and in situ aircraft measurements. For the intermediate level of ascent speed, snow can become rimed, diluting its anisotropy, and presents a challenge to unambiguous detection of an icing condition by dual pol radar. This challenge is under current study.
Williams, Earle, Donovan, Michael F., Smalley, David J., Hallowell, Robert G., Griffin, Elaine P., Hood, Kenta T., Bennett, Betty J., Wolde, Mengistu, Korolev, Alexei V.
RotorShield Advanced Rotor Blade Erosion Protection, Application to V-22F-0071-2015-102575/5/2015
ABSTRACT Rotorcraft operating in desert and shore environments continue to experience severe rotor blade erosion. To mitigate damage from sand and rain, rotor blade leading edges have historically been designed with a metallic abrasion strip that serves as sacrificial material to absorb the damage. Erosion of the metal abrasion strip can become a major contributor aircraft downtime and maintenance activities. Sand erosion takes place during takeoff and landing, or during ground operations where dust, sand, and other debris are lifted by the rotor downwash. Rain erosion occurs during aircraft operation in heavy rainfall. To alleviate the maintenance costs associated with rotor erosion, a number of research efforts have investigated alternative rotor blade abrasion strip treatments to develop new structures or coatings that are more resistant to erosion damage. The ONR RotorShield erosion coating system is a technology applied to the V-22 to enable extended erosion protection and achieves the goals of reduced maintenance and repair costs associated with erosion damage. The erosion coating technology is compliant with V-22 rotor blade requirements such as: weight; fatigue; ice protection system; lightning strike and aerodynamics.
Nissen, Jeffrey, Holemans, Peter, Venezia, Jonathan
Dual-Use Structures: Apache Empennage Integral Driveshaft Cover AntennaF-0071-2015-102515/5/2015
ABSTRACT Many modern aircraft, including rotorcraft, require conformal antennas and fairings to reduce wind drag, ice accretion, lightning strikes, and impact damage. An innovative approach to embedding Very High Frequency (VHF) antenna elements in the leading and trailing edges of a helicopter empennage has been developed. A prototype has been fabricated and tested on a mockup of a helicopter empennage, consisting of the vertical stabilizer (tail), horizontal stabilator, and gearbox. Testing has shown that the design can meet typical communications range requirements. A history of helicopter empennage antennas, the development approach, design features and key innovations, and measured results are presented and discussed. The approach can be replicated on almost any current or future aircraft or rotorcraft.
Lavin, Ronald, Pyle, Glenn, Robeson, Mark, McCarthy, Dennis
NASA Launch Pads Protected Against Lightning-Induced Power SurgesTBMG-2066810/1/2014
Circuit protection components Littelfuse Chicago, IL 773-628-1000
KSC Spaceport Weather Data ArchiveTBMG-198926/1/2014
The Spaceport Weather Data Archive provides a fully searchable database of weather data gathered at Kennedy Space Center and the Cape Canaveral Air Force Station. Weather data includes wind, temperature, and humidity data from a surface meteorological tower network; upper air soundings from both weather balloons and radar wind profilers; and data from the extensive rain gauge network. Not only can the user easily retrieve data and download it, but the user can also view graphically the weather data on a map overlay. For example, the user can enter search criteria to view all lightning strikes ending at a particular date/time, and graphically see the lightning strikes color-coded based on elapsed time for the prior seven hours. A unique feature of the software is the capability to invoke an automated playback for cloud-to-ground lightning events on a geographic overlay for a selected date and time interval.
LED DriversTBMG-196535/1/2014
SL Power Electronics (Ventura, CA) has introduced its new LE Series of LED drivers. Available in 10 models from 75 to 300 watts, the constant current LED drivers enable highly efficient LED lighting for applications that require more than eight hours per day of operating life. Featuring a wide input voltage range of 90 to 305 VAC, up to 95 percent efficiency and the ability to survive lightning strikes, the LE-Series have UL 8750 and EN61347 safety approvals with an IP67 rating and are housed in a waterproof metal case in order to withstand hot and cold temperatures in outside installations.
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.
High-Voltage, Low-Power BNC Feedthrough TerminatorTBMG-138636/1/2012
This innovation is a high-voltage, lowpower BNC (Bayonet Neill–Concelman) feedthrough that enables the user to terminate an instrumentation cable properly while connected to a high voltage, without the use of a voltage divider. This feedthrough is low power, which will not load the source, and will properly terminate the instrumentation cable to the instrumentation, even if the cable impedance is not constant.
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
Accomplishing a Meaningful Particular Risks Assessment Document2011-01-249810/18/2011
The Particular Risks Assessment Document (PRA) is the compendium of the assessments accomplished during the development of a new airplane that relate to threats to the airplane from the outside environment (e.g. birdstrike, lightning, hail) and threats to the systems from events originating in other systems (e.g. rotorburst, flailing shafts, tire and wheel burst). These assessments are accomplished to ensure the robustness of the design to survive these threats. An extensive list of threats is developed and teams are formed to evaluate each of them. The results of these studies are collated into a document that provides a single point reference for the new airplane with regard to its ability to survive all known external threats. If PRAs have been accomplished on previous programs they can be used as a starting point for the new assessment, then the systems are reevaluated against the new design and differences created by new design features need to be added to the list. The PRA is not a trivial exercise. It requires a commitment on the part of management and the allocation of resources from the safety and design communities. However, this assessment can greatly add to the robustness of the new design and can reap benefits far into the future as the design continues to be used in the aviation industry.
Dalton, John C.
Grommet Hole Reinforcement and Lightning Strike Protection in Composite Structural Assembly2011-01-261010/18/2011
Aircraft design and assembly challenges include provision of hole protection from lightning strike in fastened joints, especially in the vicinity of fuel tanks or electrical services. Installation of interference fit fasteners helps minimize the effect of lightning strike and also enhances the durability and load transfer ability of the joint. However, these are known to cause laminate damage during installation which can degrade the fastener system performance. Use of a pre-installed expanded grommet into the hole prior to installing interference fit fasteners has been shown to greatly enhance the effectiveness of the joint as well as the conductivity of electrical current into the structure to minimize arcing or plasma discharge at the fastener in the event of lightning strike. The Fatigue Technology (FTI) GromEx® system provides such hole protection for fastener installations into composites, allowing for the installation of interference fit fasteners without detrimental impact to the laminate. In a test program performed to evaluate the performance of the GromEx system under lightning strike testing, in accordance with the methods specified in SAE ARP 5416, it was found that interference fit fasteners, combined with the expanded grommets, eliminated gaps between the fastener and surrounding structure that could cause sparking during a lightning strike. These joints provide very low resistance between the fastening system and the structure and improved joint durability by more than four times. A description of the GromEx installation process, the structural benefits afforded by the GromEx system as well as the results of lightning strike simulated direct strike tests on complete tanks or tank Sections for a Zone 1A environment, are discussed in this paper.
Reid, Len, Ransom, Joy, Wehrmeister, Mark
Items per page:
1 – 50 of 192