Aging Electrical SystemsResearch ProgramRobert A. Pappas Federal Aviation AdministrationManager, Aging Electrical Systems Research Program AAR-480Prepared for:EAPAS Aging Aircraft WorkshopNovember 6, 2002

Arc Fault Circuit Breaker

OutlineBackgroundAFCB R&DFlight Test ProgramAFCB SpecificationPros/Cons of AFCB InstallationAFCB Implementation Considerations & Operational IssuesFuture arc fault R&DWrap-up / Q&A

Arc Fault Circuit Breaker Background

AFCB PurposeMitigate the effects of electrical arcing on aircraft wiring.

Background:Current Inspection TechnologyCurrent inspection and surveillance methods for aircraft wiring are limited in effectiveness and periodic in frequency.Arc fault circuit breakers provide continuous monitoring & protection.

Background:Arc FaultsPresent aircraft circuit breakers are designed to protect against over loads and short circuits.Arcing faults draw less current than hard faults and are intermittent in duration. Arcing faults can cause systems failures and fires.

Background:Typical Arcing FaultArc Voltage and Current Waveform of Arcing Fault at 10,000 Feet

Background:Wire DegradationWiring insulation degradation increases with time do to a variety of factors such as:ChaffingEnvironmental stressesMaintenance.

Degradation varies due to design, maintenance, and operational differences

Chart2

00

00

0.11428571430.2285714286

00.6535947712

0.74719800752.7397260274

1.24740124742.9106029106

2.25563909774.5112781955

Bare Wire

>50% Insulation Gone

Flight hours/aircraft

Occurances/million flight hours

Results of a Fleetwide Fuel Boost Pump Wire Inspection

737 Flight Hours Info.

737 Aircraft Statistics (as of 6/30/98)

AC Flight HoursU.S. Fleet InventoryU.S. Fleet Flight Hours*World Fleet InventoryWorld Fleet Flight Hours*

0-20K000010

20-30K21654000004931232500025

30-40K359125650005762016000035

40-50K13158950002911309500045

> 50K16196600003772262000060

Fleet86733,520,000173768,200,000

Total101,720,000

*Based upon average flight hours in rightmost column

Total 737 US Registered Aircraft**1133

737 A/C w/ > 20K hours867

737 A/C w/

Background:Commercial AFCI60 Hz AFCBs are commercially available.Aircraft AFCBs must:Be at least 50% smaller in size.Operate in an aircraft environment.Work in an aircraft electrical system.Photos courtesy Eaton Corp. and Texas Instruments

Background:Commercial AFCBPhoto courtesy Eaton Corp.

AFCBResearch and Development

AFCB ProgressTwo R&D contracts awarded in December 1999Eaton Aerospace ControlsHendry Telephone Products September 2002:Both contracts complete20 prototype AFCBs delivered and flight tested115V, 400 HzSmaller than the MS-24571 objective

AFCB Progress

AFCB ProgressLoad and Power CharacterizationExtensive load characterizationFAA B727 (N40)Navy C-9Boeing Power LabExtensive power characterizationFAA B727 (N40)Boeing Power LabNavy C-9 Nuisance trip testingFAA B727 (N40)Boeing Power Lab

AFCB ProgressTypical Flight Recorder Start-up (Current)

AFCB R&D Flight Test

R&D Flight Test:ObjectivesFly AFCBs on a variety of aircraft and electrical loadsEvaluate nuisance trippingDemonstrate AFCB technology readiness for introduction into civilian and military transport aircraft.

AFCB Installation on Navy C-9 Aircraft (VR-56)First Navy Flight of Eaton AFCB on August 24, 2001

AFCB Installation on FAA B727 (N40)Eaton AFCBsData Recording

R&D Flight Test:FAAB727 Flight Test Loads

NAMERATINGOscillating Navigation Light5ADME-23AWindow Lights10ALanding Lights Left Inboard7APassenger Cabin Ceiling Lights - Left Side15APROJECT POWER (60 hz converter)15AAUX. PITOT HEAT5AWINDOW HEAT, R4,55A

AFCB ResultsEaton Flight Test30.9 Flight Hours228.2 Total Operational Hours

Hendry Flight Test99.2 Flight Hours793.6 Total Operational HoursNote: Does not include Navy C-9 flight test data or FAA ground time

AFCB ResultsFlight Test AccomplishmentsSeveral nuisance trip modes identified, corrected, and validated.Several AFCB power supply problems identified, corrected, and validated.Several AFCB hardware problems identified, corrected, and validated.AFCB Technology ready for prime time.

AFCB Program StatusFAA has accepted and is currently processing two STC applications for AFCB installationLimited installationNon-critical circuitsDevelop operational experience

AFCB Specification Development

AE-8B1 AFCB Performance Specification Draft is nearly completeApplicable to 115V/Single Phase devices onlyBroad concurrence of the AE-8B1 committee membersAE-8B General Committee BallotSAE Council Level BallotGet the word out and support a YES vote on the specification ballot

AE-8B1 AFCB Performance Specification All current requirements for thermal circuit breaker performance retained.Arc Fault Specific Requirements:ExtensiveRigorousRepresent and address REAL conditions

AE-8B1 AFCB Performance Specification Guillotine Test

AE-8B1 AFCB Performance Specification Guillotine Test

AE-8B1 AFCB Performance Specification Wet Arc TestHot Re-Close Wet Arc TestCold Start-Up Time Test

AE-8B1 AFCB Performance Specification Loose Terminal Test

AE-8B1 AFCB Performance Specification Operation Inhibition (Masking) Test

AE-8B1 AFCB Performance Specification Nuisance Trip Immunity (Arc Fault Discrimination)

AE-8B1 AFCB Performance Specification Cross-Talk Immunity

AE-8B1 AFCB Performance Specification Feedback Immunity Test

Breaker under test

EMBED PBrush

AE-8B1 AFCB Performance Specification Other Arc Fault Performance TestsArc Fault Cycling (Endurance)Temperature (DO-160)Altitude (DO-160)EMC (DO-160)Susceptability Radiated and ConductedEmissions RadiatedLightning Induced TransientsElectrostatic Discharge

AE-8B1 AFCB Performance Specification Other Arc Fault Performance Tests (Contd)Power Quality (DO-160)AFCB Reverse Installation no adverse safety effects

AFCB Implementation Considerations and Operational Issues

AFCB Implementation Prevents catastrophic damage to wiring systemReduce arc energy for starting firesIdentifies circuits on which arc faults are occurringActively monitors circuits

AFCB Implementation Determining Overload vs. Arc Fault vs. Nuisance TripAssurance of AFCB FunctionalityAdditional wire maintenance due to potential increases in trip rates from interconnect system degradationPost trip troubleshooting, determining location of arc fault

AFCB Implementation Fire and Smoke Incident DataMaintenance DataReliability DataRisk AnalysisWiring ZonesSWAMPEnvironmental ConditionsHigh Maintenance AreasAvionics bayPassenger CabinsCargo compartments

AFCB Implementation Connected EquipmentNon-Flight Critical EquipmentPassenger/cargoFlight Critical With RedundancyEmergency Flight LoadsRisk AnalysisFunctional/PhysicalIntra-system hazards

Future AFCB R&D

Future AFCB R&DJoint FAA, NAVAIRSYSCOM, ONR, USAF28VDC, 1-25AThree-phase, 5-25AMS3320 packageCommunication interfaceRemote controlIntegration of 115V/400Hz AFCB and 28VDC into single breaker

Future AFCB R&DContract Awards PendingEaton AerospaceAMETEKScheduleYear 1 Prototype DemonstrationPossible Down SelectYears 2 & 3 Engineering Development, Test and Evaluation

AFCB Conclusions

AFCB ConclusionsPresent aircraft circuit breakers are not designed to mitigate the effects of arcing faults.115V/Single-Phase AFCB development is complete.Select mitigation/prevention technology appropriate to the hazard.

Wire Test & Inspection Technology

Wire Test & Inspection TechnologyExcited Dielectric TestBroadband Impedance MeasurementTerahertz ReflectometryWire IndenterOptical Chafe DetectorValidation Test BedPseudo-Random BinarySequence ReflectometrySmart ConnectorsNeural Network Processing ofTDR/FDR WaveformsHi-Voltage Micro-EnergyPulsed Arrested Spark Discharge

Wire Degradation Research

Wire Degradation ResearchCore Technical TeamRaytheon Technical Services Company, IndianapolisBrookhaven National LaboratoryLectromechanical Design Co. (Lectromec)Sandia National Laboratory

Wire Degradation ResearchOverall GoalModel aging characteristics of aircraft wireEstablish data for predictive techniques.Determine degradation relative to original performance specification.Use data to develop more effective inspection technologies

Wire Degradation ResearchPhase 1: Define Test Plan and QA Documentation - CompletePhase 2: Testing of Aircraft Wire October 2002 - May 2004Phase 3: Analysis and ReportingJune 2004 January 2005

Evaluation of Performance Requirements, Test Criteria and Procedures, for Aircraft Wire

Aircraft Wire PerformanceContract Award March 2002Raytheon Technical Services Company, IndianapolisContract Completion March 2003

Aircraft Wire PerformanceTask 1 Review of Current Wire Specifications completeTask 2 Obtain Wire Performance Field Data completeTask 3 Evaluation/Assessment of Field Data vs. Performance SpecificationsTask 4 Draft Minimum Wire Performance Specification

Evaluation of Aircraft Wiring Separation and Segregation Requirements and Practices

Wiring Separation and SegregationContract Award: September 2002Completion: August 2003Raytheon Technical Services Company, Indianapolis

Wiring Separation and SegregationObjectivesEvaluate past and current requirements for separation and segregationAnalyze requirements relevant to service dataIdentify potential improvements to requirementsExplore methods for assessing adequacy of separation/segregation of a particular installation

Wiring Separation and SegregationTasksObtain and analyze electrical failure data relevant to separation and segregationIdentify failure modes that render the applicable separation and segregation requirement inadequate or otherwise reducing the effectiveness of the safety margin.

Wiring Separation and SegregationTasksDevelop potential improvementsConduct tests as necessary to investigate current requirements, support investigation and verification of potential improvements

Effects of Related & Unrelated Maintenance on the Integrity of Aircraft Electrical Interconnect Systems

Maintenance EffectsContract Award: October 2002Completion: September 2003Raytheon Technical Services Company, Indianapolis

Maintenance EffectsObjectivesEvaluate effects of current maintenance practices upon the performance of the electrical interconnect system

Maintenance EffectsTasksConduct an empirical evaluation of maintenance processes and effects.Evaluate collateral maintenance effects such as contamination of wire bundles, and insulation blankets.Simulate maintenance conditions to quantify maintenance effects

Maintenance EffectsTasksSimulate maintenance conditions to quantify maintenance effects on:Wire degradationFlammabilityCorrosion inhibiting compounds, cleaning compounds, lubricants, etc.Debris

Evaluation of Mixed Wire Types

Evaluation of Mixed Wire TypesEvaluation of proposals completeAward process underwayBudget - continuing resolution may delay funds availability and hence award.Nine month duration after award

New Projects

In-Service Performance MonitoringMonitor in-service changes to wire performance and properties5-year monitoring program/20 year life windowStaggered aircraft ages new, 5, 10, & 15 years old.

In-Service Performance MonitoringCoordinate between FAA, OEM, Operator(s)Locations, parameters of interest, instrumentation, etc.Certification by FAA

Evaluation of Aging ComponentsPerformance evaluation of aging componentsConnectors, splices, etc.SwitchesRCCBs, Contactors, Relays, etc.

Advanced Circuit ProtectionExploration of advanced concepts for new and/or improved methods of circuit protectionApplication of arc fault, ground fault, and other concepts

Questions