Aging Electrical Systems Research Program Robert A. Pappas · Federal Aviation Administration Manager, Aging Electrical Systems Research Program · AAR-480 Prepared for: EAPAS Aging Aircraft Workshop November 6, 2002

Arc Fault Circuit Breaker

Outline Background AFCB R&D Flight Test Program AFCB Specification Pros/Cons of AFCB Installation AFCB Implementation Considerations & Operational Issues Future arc fault R&D Wrap-up / Q&A

Arc Fault Circuit Breaker Background

AFCB Purpose Mitigate the effects of electrical arcing on aircraft wiring.

Background: Current Inspection Technology Current 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 Faults Present 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 Fault Arc Voltage and Current Waveform of Arcing Fault at 10,000 Feet

Background: Wire Degradation Wiring insulation degradation increases with time do to a variety of factors such as: –Chaffing –Environmental stresses –Maintenance. Degradation varies due to design, maintenance, and operational differences

Background: Commercial AFCI 60 Hz AFCB’s are commercially available. Aircraft AFCB’s 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 AFCB Photo courtesy Eaton Corp.

AFCB Research and Development

AFCB Progress Two R&D contracts awarded in December 1999 –Eaton Aerospace Controls –Hendry Telephone Products September 2002: –Both contracts complete –20 prototype AFCBs delivered and flight tested –115V, 400 Hz –Smaller than the MS objective

AFCB Progress

Load and Power Characterization –Extensive load characterization FAA B727 (N40) Navy C-9 Boeing Power Lab –Extensive power characterization FAA B727 (N40) Boeing Power Lab Navy C-9 – Nuisance trip testing FAA B727 (N40) Boeing Power Lab

AFCB Progress Typical Flight Recorder Start-up (Current)

AFCB R&D Flight Test

R&D Flight Test: Objectives Fly AFCB’s on a variety of aircraft and electrical loads Evaluate nuisance tripping Demonstrate 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 AFCB’s Data Recording

R&D Flight Test: FAA B727 Flight Test Loads NAMERATING Oscillating Navigation Light5A DME-23A Window Lights10A Landing Lights Left Inboard7A Passenger Cabin Ceiling Lights - Left Side 15A PROJECT POWER (60 hz converter) 15A AUX. PITOT HEAT5A WINDOW HEAT, R4,55A

AFCB Results Eaton Flight Test –30.9 Flight Hours –228.2 Total Operational Hours Hendry Flight Test –99.2 Flight Hours –793.6 Total Operational Hours Note: Does not include Navy C-9 flight test data or FAA ground time

AFCB Results Flight Test Accomplishments –Several 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 Status FAA has accepted and is currently processing two STC applications for AFCB installation Limited installation Non-critical circuits Develop operational experience

AFCB Specification Development

Draft is nearly complete Applicable to 115V/Single Phase devices only Broad concurrence of the AE-8B1 committee members AE-8B General Committee Ballot SAE Council Level Ballot Get 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: –Extensive –Rigorous –Represent 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 Test Hot Re-Close Wet Arc Test Cold 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 AE-8B1 AFCB Performance Specification

Other Arc Fault Performance Tests –Arc Fault Cycling (Endurance) –Temperature (DO-160) –Altitude (DO-160) –EMC (DO-160) Susceptability – Radiated and Conducted Emissions – Radiated Lightning Induced Transients Electrostatic Discharge AE-8B1 AFCB Performance Specification

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

AFCB Implementation Considerations and Operational Issues

AFCB Implementation Prevents catastrophic damage to wiring system Reduce arc energy for starting fires Identifies circuits on which arc faults are occurring Actively monitors circuits

Determining Overload vs. Arc Fault vs. Nuisance Trip Assurance of AFCB Functionality Additional wire maintenance due to potential increases in trip rates from interconnect system degradation Post trip troubleshooting, determining location of arc fault AFCB Implementation

Fire and Smoke Incident Data Maintenance Data Reliability Data Risk Analysis Wiring Zones –SWAMP –Environmental Conditions –High Maintenance Areas Avionics bay Passenger Cabins Cargo compartments AFCB Implementation

Connected Equipment –Non-Flight Critical Equipment Passenger/cargo –Flight Critical With Redundancy –Emergency Flight Loads –Risk Analysis Functional/Physical Intra-system hazards AFCB Implementation

Future AFCB R&D

Joint FAA, NAVAIRSYSCOM, ONR, USAF 28VDC, 1-25A Three-phase, 5-25A MS3320 package Communication interface Remote control Integration of 115V/400Hz AFCB and 28VDC into single breaker

Future AFCB R&D Contract Awards Pending –Eaton Aerospace –AMETEK Schedule –Year 1 – Prototype Demonstration –Possible Down Select –Years 2 & 3 – Engineering Development, Test and Evaluation

AFCB Conclusions

Present 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. AFCB Conclusions

Wire Test & Inspection Technology

Excited Dielectric Test Broadband Impedance Measurement Terahertz Reflectometry Wire Indenter Optical Chafe Detector Validation Test Bed Pseudo-Random Binary Sequence Reflectometry Smart Connectors Neural Network Processing of TDR/FDR Waveforms Hi-Voltage Micro-EnergyPulsed Arrested Spark Discharge

Wire Degradation Research

Core Technical Team Raytheon Technical Services Company, Indianapolis Brookhaven National Laboratory Lectromechanical Design Co. (Lectromec) Sandia National Laboratory

Wire Degradation Research Overall Goal Model aging characteristics of aircraft wire  Establish data for predictive techniques.  Determine degradation relative to original performance specification.  Use data to develop more effective inspection technologies

Wire Degradation Research Phase 1: Define Test Plan and QA Documentation - Complete Phase 2: Testing of Aircraft Wire October May 2004 Phase 3: Analysis and Reporting June 2004 – January 2005

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

Contract Award – March 2002 Raytheon Technical Services Company, Indianapolis Contract Completion – March 2003 Aircraft Wire Performance

Task 1 – Review of Current Wire Specifications – complete Task 2 – Obtain Wire Performance Field Data – complete Task 3 – Evaluation/Assessment of Field Data vs. Performance Specifications Task 4 – Draft Minimum Wire Performance Specification Aircraft Wire Performance

Evaluation of Aircraft Wiring Separation and Segregation Requirements and Practices

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

Objectives Evaluate past and current requirements for separation and segregation Analyze requirements relevant to service data Identify potential improvements to requirements Explore methods for assessing adequacy of separation/segregation of a particular installation Wiring Separation and Segregation

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

Tasks Develop potential improvements Conduct tests as necessary to investigate current requirements, support investigation and verification of potential improvements Wiring Separation and Segregation

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

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

Objectives Evaluate effects of current maintenance practices upon the performance of the electrical interconnect system Maintenance Effects

Tasks Conduct 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 Effects

Tasks Simulate maintenance conditions to quantify maintenance effects on: –Wire degradation –Flammability Corrosion inhibiting compounds, cleaning compounds, lubricants, etc. Debris Maintenance Effects

Evaluation of Mixed Wire Types

Evaluation of proposals complete Award process underway Budget - continuing resolution may delay funds availability and hence award. Nine month duration after award Evaluation of Mixed Wire Types

New Projects

Monitor in-service changes to wire performance and properties 5-year monitoring program/20 year life window Staggered aircraft ages – new, 5, 10, & 15 years old. In-Service Performance Monitoring

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

Performance evaluation of aging components –Connectors, splices, etc. –Switches –RCCB’s, Contactors, Relays, etc. Evaluation of Aging Components

Exploration of advanced concepts for new and/or improved methods of circuit protection Application of arc fault, ground fault, and other concepts Advanced Circuit Protection

Questions