Transcript History of System Lightning Requirements

History of System Lightning Requirements- Highlights
• Chronology
• Technical Overview
• SAE Guidance Documents
• Requirements
Chronology
• SAE
– In Response to a Military Request for Assistance, SAE Forms
Special Task F-Approximately Four Decades Ago
•
– Special Task F Becomes AE4L-Approximately Three Decades Ago
– AE4L Becomes AE2-1999
Military
– MIL-STD-1757- Approximately Three Decades Ago
– MIL-STD-1795- Approximately Three Decades Ago
– MIL-STD 461 Upgrade-1993
– MIL-STD-464 - 1997
• FAA
– Original Regulation-Approximately Three Decades Ago
– Original AC 20-136-Between Two to Three Decades Ago
Special Task F
• Determine Lightning Environment from Measurements During
Strikes to Towers
• Followed the Space Shuttle lightning criteria committee and NASA
07636
• Developed MIL-STD-1757
• Developed MIL-STD-1795
• Published Red and Blue Book Committee Reports
AE2/AE4L
• Establish Charter
– Scope
 It is the Duty of the Committee to Produce Advisory Materials for the
Aerospace Community in the Following Areas:
 The Natural Lightning Environment and Related Atmospheric Electrical
Standards
 Protection of Aerospace Vehicles from the Effects of Lightning and Other
Atmospheric Electrical Environments
 Means of Verifying the Adequacy of Protection Measures
 Standardized Simulation and Test Methods for Lightning and Other
Atmospheric Electrical Environments
– Objectives
 Provide a Forum for the Exchange of Technical Information Relating to the
Above Technology Areas
 Share and Coordinate the Development of Technical Material with the
Comparable International Communities along with Harmonizing the U.S. and
International Forums within the Committee’s Scope
AE2/AE4L (Continued)
– Objectives (Continued)
 Compile and Review Information on Naturally Occurring Lightning and Other
Atmospheric Electrical Environments
 Characterize and Define Engineering Standards Based on Naturally Occurring
Lightning and Other Atmospheric Electrical Environments
 Develop Simulation and Test Procedures for Use in Evaluating Lightning and
other Electrical Effects on Aerospace and Systems
 Identify Areas where Knowledge is Lacking and Recommend Research to Fill in
Knowledge Gaps
 Provide a Forum for the Exchange of Technical Information Relating to the
Above Technology Areas
 Share and Coordinate the Development of Technical Material with the
Comparable International Communities along with Harmonizing the U.S. and
International Forums within the Committee’s Scope
AE2/AE4L (Continued)
• Determine (Multiple Burst Environment from In-Flight Measurements
During Lightning Strikes to the F-106)-Between Two and Three
Decades Ago
• Publish Guidance Documents
Technical - Overview
• Lightning Environment Characterization for System
Requirements-Between Three to Four Decades Ago
• Relationship Between Waveforms 1,2 and 3Approximately Four 4 Decades Ago
• Waveform Derivation-Between Three to Four Decades
Ago
• Voltage/Current Levels-Between Three to Four Decades
Ago
• Indirect Effects
Lightning Environment Characterization for System Requirements
• External
– Data from Measurements of Lightning Strikes to Towers-Approximately
Four Decades Ago
 Current Components A and D
 Multiple Stroke
– In-Flight Measurements During Lightning Strikes to an AirplaneApproximately Three Decades Ago
 Current Component H
 Multiple Burst
• Internal
– Internal Magnetic Fields Due to Aperture Coupling of Current
Components A,D and H External Magnetic Fields
– Waveforms 1,2 and 3 Voltages and Currents also Waveform 6 CurrentCoupling of the Current Components A and H Internal Magnetic Fields
(Forcing Function) to Aircraft Wiring
Lightning Environment Characterization for System Requirements
(Continued)
• Internal (Continued)
– Waveform 3H Voltages and Currents also Waveform 6 Current- Coupling
of the Current Component H Internal Magnetic Fields to Aircraft Wiring
– Waveforms 4 and 5 Voltages and Currents-Resistive Drop Across an
Aerospace Vehicle Structure Due to Current Component A
Relationship Between Waveforms 1,2 and 3
• Analytic Derivation from B-1 NEMP Threat
– Maxwell Partial Differential Equations For an Electromagnetically Simple
Configuration (a Scatter where the Diameter < < than the Length)
Reduces to a Linear Differential Equation
– When the Forcing Function is the Current Component A Magnetic Field,
the Differential Equation Solution Yields:
 Criteria for an Electrically Long or Short Configuration
 Criteria for an Electrically Long Configuration-Solution Contains Waveform 3
Only
 Electrically Short Configuration-Solution Contains a Combination of Waveform
2 and Waveform 3
 Electrically Long Configuration-Solution Contains Waveform 3 Only
Relationship Between Waveforms 1,2 and 3 (Continued)
• Also Derived:
– Two as the Ratio of Voltage Waveform 3 to Voltage Waveform 2 (Solution
from Linear Differential Equation Approximation of Maxwell’s EquationsRatio Emphasizes Waveform 2 Voltage)
– Five as the Ratio of Waveform 2 Voltage to Waveform 1 Current
 The Absolute Value of Waveform 2 Voltage is Equal to Inductance Times the
Absolute Value of the Derivative of Waveform 1 Current (Faraday’s Equation
from Faraday’s Law)
 Inductance is in the 1 to 2 Micro-Henry Range
–
Realistic Estimate for The Inductance Minimum Value Resulted in the Minimum Waveform
2 Voltage to Waveform 1 Current Ratio of Five
–
Value for Inductance was a Result of a Realistic Estimate of Minimum Wire Length
 Equation Used for Current Component A Peaked at Two Micro-Seconds
 Equation of Waveform 1 Current the Same Form as the Equation for Current Component A
– Twenty Five (Conservative Value of Traveling Wave Characteristic
Impedance) as the Ratio of Waveform 3 Voltage to Waveform 3 Current
Waveform Derivation-Between Three and Four Decades Ago
• Waveform 1-Drived From Analysis and Pulse Testing Between Three
and Four Decades Ago
• Waveform 2-Drived From Analysis and Pulse Testing Between Three
and Four Decades Ago
• Waveform 3-Drived From Analysis and Pulse Testing Between Three
and Four Decades Ago
• Waveform 3 Frequencies (1MHz and 10MHz) Accommodates Range
of Aircraft Geometries
• Waveform 4-Drived From Analysis and Pulse Testing Between Three
and Four Decades Ago
• Waveform 5-From Pulse Testing Approximately Three Decades Ago
• Waveforms 3H and 6-From Pulse Testing Approximately Three
Decades Ago
Voltage/Current Levels
• For a Single Wire, Empiric (Pulse Testing) Measurements Verify:
– Two as the Ratio of Waveform 3 Voltage to Waveform 2 Voltage-Value that
was Analytically Derived
– Five as the Ratio of Waveform 2 Voltage to Waveform 1 Current-Value that
was Analytically Derived
– Twenty Five as the Ratio of Waveform 3 Voltage to Waveform 3 CurrentConservative Value for the Traveling Wave Characteristic Impedance
• Waveform 2 and Waveform 3 in the Solution for the Electrically Short
Configuration Decomposed into Individual Waveforms (Waveform 2
Voltage Component and Waveform 3 Voltage Component)
• Current Component A-For Cables, Ratios Based on Pulse Testing
Measurements
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One Half as the Ratio of Waveform 2 Voltage to Waveform 1 Current
Five as the Ratio of Waveform 3 Voltage to Waveform 3 Current
One Half as the Ratio of Waveform 4 Voltage to Waveform 1 Current
One Third as the Ratio of Waveform 5 Current to Waveform 4 Voltage
Voltage/Current Levels (Continued)
• Current Component H-Ratio For Cables, Based on Pulse Testing
Measurements
– Sixty as the Ratio of Waveform 3H Voltage to Waveform 3H Current-Value
of Traveling Wave Characteristic Impedance also
– For Current Component H Magnetic Field All Circuits of Practical Length
Will be Electrically Long and Waveform 3H will be the Only Response
– Waveform 6 Current Only (Circuits that Are Completely Shielded)
• Provides Design Criteria that is Independent of Aerospace Vehicle
Type and Installation Practices
• Systems Integrator Tool that Enables:
– A System Integrator to Specify Interface Circuit Voltages and CurrentsResulting from the Control of Internal Magnetic Fields by Installation
Design Practices
– A System Integrator to Select Electrical/Electronic Equipment-Qualified to
the Unique Voltage/Current Requirements Resulting From his Installation
Voltage/Current Levels (Continued)
• Systems Integrator Tool that Enables(Continued):
– A System Integrator to Select Electrical/Electronic Equipment that has
–
been Qualified to Industry Standards Resulting in Equipment that is
Compatible with His Installation Requirements
Installation Design (shielding, etc) Controls the Magnitude of Internal
Magnetic Fields and the Resulting Voltages and Currents Induced by
those Fields)
• Equipment Manufacturer Tool that Enables:
– Choice of a Level from an Industry Standard to Qualify Equipment to
Customer Requirements
– Choice of a Level from an Industry Standard to Qualify Equipment Based
on Market Demands
Indirect Effects
• Electronic Component Damage (Hard Fault-Digital Circuit)Waveforms 1,2,3(1MHz),4,5,6 (Possibly)and Multiple Stroke
– Non-Recoverable Circuit
– One or More Component Replacement
• Electronic Circuit Upset (Soft Fault-Digital Circuit): Waveforms 1,2,3,
(1MHz and10MHz),4 6, Multiple Stroke and Multiple Burst
– Circuit Recoverable
– System/Equipment Recoverable
SAE Guidance Documents
• Red Book Committee Report (Superseded by Blue Book)
• Blue Book Committee Report, “Lightning Test Waveforms
and Techniques for Aerospace Vehicles and Hardware”1978
• Yellow Book Committee Report AE4L-81-2, “Test
Waveforms and Techniques for Assessing the Effects of
Lightning-Induced Transients”
• Original Orange Book Committee Report AE4L-87-3,
“Protection of Aircraft Electrical/Electronic Systems
Against the Indirect Effects of Lightning“
SAE Guidance Documents (Continued)
• Committee Report AE4L-87-3 Rev C, “Certification of
Aircraft Electrical/Electronic Systems Against the Indirect
Effects of Lightning“
• Purple Book Committee Report AE4L-97-4, “Aircraft
Lightning Environment and Related Test Waveforms
Standard“
• ARP 5412, “Aircraft Lightning Environment and Related
Test Waveforms ”-Between One to Three Decades Ago
• ARP 5413, “Certification of Aircraft Electrical/Electronic
Systems for the Indirect Effects of Lightning” (Provided
the Technical Basis for AC 20-136B and was Superseded
by AC 20-136B)- Between One to Three Decades Ago
SAE Guidance Documents (Continued)
• ARP 5415, “User’s Manual for Certification of Aircraft
Electrical/Electronic Systems for the Indirect Effects of
Lightning”-2001
• ARP 5416, “Aircraft Lightning Test Methods”-Proposed
Draft 2005
• Technical Basis
– The Technical Content within the Blue, Yellow and Orange Books
Provided the Technical Basis for the Purple Book, ARPs 5412,
5413, 5415 and MIL-STD-464
– Airframe and Equipment Suppliers Testing Experience Provided
the Technical Basis for ARP 5416
Blue Book Committee Report
• Defined Lightning Environment from which that Portion Relevant to
System Requirements Can be Extracted
• Lightning Environment Relevant to System Requirements-Indirect
Effects on Electronic Systems
– Current Components A and D
– Multiple Stroke-Current Component A Followed by a Half Value Current
Component D Group of Twenty Three
Committee Report AE4L-81-2
• System Test
– Triple Plate
– Cable Injection
• Equipment Test
– Cable Injection for Upset/Damage Tolerance-Pseudo System Test
– Circuit Interface Injection for Upset and Damage Tolerance-Pseudo Pin
–
Test
Direct Circuit Injection for Damage Tolerance-Pin Test
• Defined Lightning Multiple Burst Environment
– Current Component H
– Multiple Burst-Twenty Four Bursts where each Burst is Composed of
Twenty Current Component H Pulses
• Introduction of Waveform 4 Voltage and Current for Upset Direct
Circuit Injection (Damage Tolerance)
Committee Report AE4L-81-2 (Continued)
• Description of Waveforms 1,2,3 and 4
– Waveform 1 Peaks at Two Micro-Seconds
– Waveform 1,2 and 4 Descriptions Eventually Re-adjusted
• Table of 5 Levels that give Voltage to Current Ratios for an Individual
Interface Circuit
– Each Level Provides a Description of Equipment Vulnerability that Implies
an Equipment Qualification Requirement for Each Interface Circuit
– Implies a Requirement for Installation Designers to Select a Level and
–
then Control the Internal Environment to be Compatible with the Level
that has been Selected
Levels Lower than Level 5 are separated by a factor of Approximately 2.5Engineering Judgment
Committee Report AE4L-81-2 (Continued)
• Level Descriptions (Equipment Focus)
– Level 5
Is an upper limit on transients to which subsystem equipment should be exposed.
Transients which lightning could Induce in long and/or exposed wiring should be
controlled to be consistent with this level. The power associated with this level represents
a threat to most electronic interface circuits and the impact on equipment practices will
be significant. Additionally, the open circuit voltage associated with is within region where
the withstand capability of the insulation medium (air, fiberglass, teflon, etc.) at equipment
connectors or between equipment circuit paths could be exceeded.
– Level 4
Is representative of severe transients which may appear on power lines and is
comparable to the power line transients defined in MIL-STD-704 (Waveform 2). It is also
representative of the upper limits which have been defined for induced interface wiring
transients that may be produced by a nuclear electromagnetic pulse (NEMP) and that
form equipment survivability/vulnerability (SV) requirements (Waveform 3). The level is
appropriate for equipment designed to include such requirements. Lightning induced
transients should be controlled to be consistent with such NEMP S/V levels. The power
associated with this is relatively severe and its impact on equipment design practices will
probably be significant.
Committee Report AE4L-81-2 (Continued)
• Level Description (Continued)
– Level 3
Is Representative of the more intense transients which may be produced during normal
operation.
– Level 2
Is intended for equipment which will be installed in environments where lighting-induced
transients would be controlled to a level which is consistent with that represented by MILSTD-461/462 or similar standards, This level is considered to be consistent with good
engineering for such equipment and should have a relatively minor impact on the
associated design practices.
– Level 1
Is intended for off-the-shelf noncritical equipment which will be installed in a controlled
environment. It is the minimum level considered to be consistent with good engineering
practice.
Committee Report AE4L-87-3 (Orange Book)
• Approaches to Compliance
• Margins and Verification Methods
– Margin Defined as the Difference Between TCL and ETDL
 Transient Control Level (TCL)
 Equipment Transient Design Level (EDTL)
– Verification Methods
 Test
 Analysis
 Test and Analysis
• Major Elements of Verification Compliance
• Maintenance and Surveillance
Committee Report AE4L-87-3 (Continued)
• Description of:
– Current Component A Adjusted-Peaks in 6.4 Micro-Seconds
– Description of Current Component H-Peaks in Approximately 2 NanoSeconds
– Description of Multiple Stroke
– Description of Multiple Burst
• Description of Waveforms 1,2 and 4 Adjusted-Because of Current
Component A Magnetic Field, Waveforms 1 and 4 Peak at 6.4 MicroSeconds
• 1 MHz and 10 MHz Waveform 3 Frequencies Account for the Range of
Aircraft Dimensions (Engineering Judgment)
• Ratios of Voltage in Yellow Book Table of Levels, are Retained in
Orange Book Levels
Committee Report AE4L-87-3 (Continued)
• Level Descriptions (Installation Focus)
– Levels 4 and 5
Are for equipment and interconnect wiring that will installed in severe electromagnetic
environments. Such levels might be found in all-composite aircraft, where special
shielding practices have not been employed.
– Level 3
Is typical for equipment and interconnect wiring that will be installed in a moderate
environment such as the more electromagnetically open areas (eg, cockpit) of an aircraft
composed principally of metal.
– Level 2
Is typical for equipment and interconnect wiring that will be installed in a controlled
environment such as an enclosed avionics bay of an all metal aircraft.
– Level 1
Not Applicable.
Committee Report AE4L-97-4
• Environment Information and Test Waveforms Removed from AC 20
– 136 and AC 20 – 53 and Included in This Document
• Natural Lightning Description
• Lightning Interactions with Aircraft
• Idealized Standard Lightning Environment
• Idealized Standard Induced Transient Waveforms
ARP 5412
• Natural Lightning Description
• Lightning Interaction with Aircraft
• Idealized Standard Lightning Environment
• Idealized Standard Induced Transient Waveforms
• Summary of Waveforms/Waveform Sets
ARP 5415
• Approaches to Compliance
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Review Safety Assessment
Determine the Lightning Strike for the Aircraft
Establish the Exterior Lightning Environment for the Zone
Establish the Exterior Effects of the Internal Environment
Establish Transient Control Levels and Equipment Transient Design Level
Verify Compliance
• Effects of Induced Transients
– Component Damage
– System Functional Upset
• Margins and Verification Methods
ARP 5415 (Continued)
• Major Elements of Compliance
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–
–
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Level A Requirements
Level B and Level C Requirements
Example 1 – System Test Levels Developed from Low Current Pulse Test
Example 2 – System Test Levels Developed from Low Current Pulse Test
Example 3 – System Test Levels Developed from Swept Frequency Test
• Maintenance, Surveillance, Repair and Modification
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–
–
Maintenance Procedures and Lightning Protection
Aircraft Modification and Lightning Protection
Protection Assurance Program
In-Service Maintenance Test Techniques
ARP 5416
• Planning of Lightning Effects Tests
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Test Object Conformity
Test Procedure
Measurement Set-UP Calibration
Test Safety Aspects
Test Set-UP
Test Object Design
Waveform Scaling
Waveform Application
Concurrent Testing
ARP 5416 (Continued)
• Indirect Effects Test Methods
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Aircraft Tests
Return Conductor Arrangement
Measurements Set-UP Calibration
Swept
Pulse Test
Tests for Equipment/Systems
Equipment Damage Tolerance Tests
Equipment Functional Upset Tests
System Functional Upset Tests
Wire Bundle Shield Transfer Function Test
Wire Bundle Shield Transfer Function Using Lightning Pulse Injection
Method
– Wire Bundle Shield Transfer Function Using Swept Frequency Test
– Shield/Conductor Handling Test
Lightning System Functional Upset Testing
SAE ARP5416 Section 6.3.4:
Applies Multiple Stroke and Multiple Burst Environments to
Systems Comprised of Multiple Boxes and Cables via
Simultaneous Injection
Requirements
• Military
• FAA
• RTCA-DO160/Section 22
Military
• MIL-STD-1757, “Lightning Qualification Techniques for Aerospace
Vehicles and Hardware” (Environment Definition that Included
Current Components A and D which are Relevant to System
Requirements)
• MIL-STD-1795, “Lightning Protection of Aerospace Vehicles and
Hardware” (see MIL-STD-1757)
• MIL-STD-461 (Upgraded to Include Equipment Tests for Lightning
Effects)
• MIL-STD-464 (Lightning Environment Section Extracted from MILSTD-1757 and ARP 5412)
FAA
• Regulation
• AC 20-136
Regulation-Present
CFRs 23.1306, 25.1316, 27.1316, 29.1316
(a) Each electrical and electronic system that performs a function, for which failure would
prevent the continued safe flight and landing of the airplane, must be designed and
installed so that1.
2.
The function is not adversely affected during and after the time the airplane the airplane is
exposed to lightning and
The system automatically recovers normal operation of that function in a timely after the airplane
is exposed to lightning.
(b) Each electrical and electronic system that performs a function, for which failure would
reduce the capability of the airplane or the ability of the flightcrew to respond to an
adverse operating condition, must be designed and installed so that the function
recovers normal operation in a timely manner after the airplane is exposed to lightning.
AC 20-136 “Aircraft Electrical and Electronic System Lightning Protection”
• A Means but not the Only Means to Show Compliance With 23.1306, 25.1309,
27.1309 and 29.1309
• Steps for showing Compliance
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Identify the systems to be assessed
Determine the lightning strike zones for the aircraft
Establish the aircraft lightning environment for each zone
Determine the lightning transient environment associated with the system
Establish Equipment Design Transient Levels (EDTLs also see Orange Book) and
Aircraft Actual Transient Levels (ATLs): the Difference Between EDTL and ATL is
the Margin
– Verify compliance to the requirements
– Take corrective measures if needed
• Effects of Transients
– Component Damage
– System Functional Upset
AC 20-136 (Continued)
• Level A System Lightning Certification
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Identify Level A Systems
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Verify System EDTLs Using System Qualification Tests
Establish System EDTLs
Determine ATLs Using Aircraft Testing
Determine ATLs Using Analysis
Determine ATLs Using Similarity
Determine Transient Levels Using DO160/Section 22 Guidance for Level A
Displays Only
Verify System EDTLs Using Existing System Data (Similarity)
Verify Compliance to the Requirements
Take Corrective Measures
AC 20-136 (Continued)
• Level B and C System Lightning Certification
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Identify Level B and C Systems
Establish EDTLs
Verify System EDTLs Using Equipment Qualification Tests
Verify System EDTLs Using Existing Equipment Data (Similarity)
Take Corrective Measures
Maintenance and Surveillance
• AC 20-136 Environment Information Removed
System Classification Levels
• Level A-Each Electrical and Electronic System that Performs a Function, for which a
Failure would Prevent the Continued Safe Flight and Landing of the Aircraft
• Level B and C-Each Electrical and Electronic System that Performs a Function, for
which a Failure would Reduce the Capability of the Aircraft or the Ability of the
Flightcrew to Respond to an Adverse Operating Condition
RTCA/DO160 Section 22
• Original- Developed in Conjunction with AE4L-87-3
• DO160/Section 22 Revision G
– Definition of Categories
– Tables of Levels (Requirement) for:
 Cable Induction
 Ground Injection
 Direct Interface Injection (Pin)
– Voltage to Current Ratios are Based Upon Ground Tests for:
 Cable Induction
 Ground Injection
– Specification of Test Setup and Procedures for:
 Cable Induction
 Ground Injection
 Direct Interface Injection
RTCA/DO160 Section 22 (Continued)
• DO160/Section 22 Revision G (Continued)
– Waveform 5
 Description
 Current to Voltage ratio Based on Ground Tests
– Multiple Stroke
– Multiple Burst
Equipment Lightning Indirect Effects Testing
DO160 Section 22: To Assess Damage and Upset-Applies
Lightning Indirect Effects Transients (Voltages and
Currents) to Equipment Interfaces via Cable Injection,
Ground Injection and Direct Injection