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AD-A257 321 d OOTFAP.O9R416 Rotorcraft Health and Usage Monitoring Systems - * 1 ?304tch an Dveloomnt Srv co A Literature Survey WaVisnrton. 0 C .0591 Larry Miller Barbara McQuiston Jell Frenster Diane Wohler Systems Control Technology, Inc. 1611 N. Kent Street. Suite 910 Arlington. VA 22209 DTIC ELECTE SNOVI 6 1992D S C May 1991 Final Report This Document Contains issing Page/s That Are Original Document This document is available to the public through the National Technical Information Service. Springfield. Virginia 22161. 92-29558 U.S DefolNint al Transpola1on r ,eafvi Avialgon

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Page 1: AD-A257 321 - Defense Technical Information Center · monitoring (HUMS) technology. ... 3.10 Advanced Avionic Architecture Maintenance/ ... 3.14 Light Helicopter - Integrated Diagnostics

AD-A257 321 d

OOTFAP.O9R416 Rotorcraft Health andUsage Monitoring Systems -

*1 ?304tch an Dveloomnt Srv co A Literature SurveyWaVisnrton. 0 C .0591

Larry MillerBarbara McQuistonJell FrensterDiane Wohler

Systems Control Technology, Inc.1611 N. Kent Street. Suite 910Arlington. VA 22209

DTICELECTE

SNOVI 6 1992DS CMay 1991

Final Report

This Document Containsissing Page/s That Are

Original Document This document is available to the public

through the National Technical Information

Service. Springfield. Virginia 22161.

92-29558

U.S DefolNintal Transpola1on

r ,eafvi Avialgon

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NOTICE

This document is disseminated under the sponsorship of the U.S.Department of Transportation in the interest of informationexchange. The United States Government assumes no liability forthe contents or use thereof.

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aU.S.Deportmn-t 800 Independence Ave., S.W.

of Transportation Washington, D.C. 20591

Federal AviationAdministration

OCT 2 2 1992

Dear Colleague:

This technical report, Rotororaft Health and Usage onitoringSystems - A Literature Survey (FAA/RD-91/6), describes theresults of an extensive literature search of health and usagemonitoring (HUMS) technology. Based on an analysis of overl,n.0Q abstracts, this report describes 20 systems and theabstracts of 90 papers pertinent to rotorcraft HUMS.

This document is part of an effort to establish a foundation ofknowledge and information to support FAA rotorcraftcertification requirements. This document has been prepared atthe request of the FAA's Rotorcraft Certification Directoratein response to that office's expectations for increased HUMsrelated requirements. The rotorcraft industry is developing anumber of techniques, methodologies, and associated equipmentrelated to monitoring the health and usage of critical flightcomponents. The increased application of artificialintelligence technology and expert systems has significantpromise in increasing accuracy and effectiveness. Militaryapplications of such diagnostics and related "black box"equipment to reduce maintenance requirements and increaseaircraft flight availability could potentially benefit civilianoperators in their challenge to stay in the "black"economically.

In continuing to meet their responsibility for thecertification of aircraft and equipment they contain, the FAAexpects to develop detailed certification addressing aircraftand equipment that incorporate HUMS. The immediate goal of theFAA is to gain a better understanding of what industry isdeveloping in the HUMS area. The goal of this report was theidentification of the firms involved, key people, and thedegree of technology maturity which may allow for someairworthiness credit to be given.

A0I Faa for ..

WDDJames 1. McDaniel0Program Manager JUtitat .Vertical Flight Program Office

Av.ilablllty Co.a!Aail cad/or.. .

""... ". , :' " "Diot Lic lal

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Technical Report Documentaton Page1. Report No. 2. Government Accession No. 3. Recipient's Catalog No.

DOT/FAANRD-91/6

4. Title and Subtitle 5. Report DateMay 1991

Rotorcraft Health and Usage Monitoring 6. Performing Organization CodeSystem s - A Literature Survey 8._ erf rmig_ rgaizaioRe ortNo

7. Author (s) 8. Performing Organization Report No.

Larry Miller, Barbara McQuiston, Jeff Frensteir, Diane Wohler 91 RR-5

9. Performing Organization Name and Address 10. Work Unit No. (TRAIS)Systems Control Technology, Inc.1611 North Kent Street, Suite 910 11. Contract or Grant No.Arlington, Virginia 22209 DTFA01-87-C.00014

12. Sponsonng Agency Name and Address 13. Type Report and Period CoveredU.S. Deoartment of Transportation Final ReportFederal Aviation Administration800 Independence Avenue, S.W. 14. Sponsoring Agency CodaWashington. D.C. 20591 ARD -30, ASW -1io

15. Supplementary Notes

ARD - 30 Vertical Flight Program Office, ASW- 110 Southwest Region, Rotorcraft Standards Staff

16. Abstract

The rotorcraft industry is developing a number of techniques, methodologies, and associated equipment formonitoring health and usage of critical rotorcraft flight components, Industry is planning to incorporate thistechnology on a number of new aircraft. The Federal Aviation Administration (FAA) has the responsibility forcertification of these aircraft and the equipment they contain. This effort Is concerned with the health andusage equipment. To best accomplish the certification of these equipment, the FAA expects to developdetailed certification criteria addressing specific issues of concern.

In the near-term, the FAA objective is to develop a better understanding of what Is being developed byindustry (with emphasis on United States industry), what firms are involved, who are the key peopleInvolved, what pans of this technology are mature to the point that some airworthiness credit may beappropriate, and what parts of this technology are not yet mature. With Information such as this, the issuesthat need to be address via certification criteria can be determined quickly,

This effort is principally Intended to provide support in reaching the FAA's near-term objectives. This reportdescribes the results of an extensive literature search of health and usage monitoring technology. Over1,000 abstracts were reviewed and analyzed. The report contains a description of 20 systems and abstfactsof 90 papers pertinent to health and usage monitoring.

17. Key Words 18. Distnbution StatementArtificial Intelligence Helicopter This document is available to the publicDiagnostics Maintenance through the National Technical InformationHealth and Usage Monitors Rotorcraft Service, Springfield, Virginia 22161.

19. Security ClasF. (of this repoo) 20. Secunty Classf. (of this page) 21. No. of Pages 22. PriceUnclassified Unclassified 1 71

Form DOT F 1700.7 (8-72) Reproduction ot this document Is authorized

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TABLE OF CONTENTS

Page1.0 Introduction ............................................. 1

1.1 Literature Search ................................... 11.1.1 Purpose ...................................... 11.1.2 Requirement .................................. 11.1.3 Technical Approach ........................... 11.1.4 Data Sources ................................ 21.1.5 Literature Search Products ................... 2

1.2 Industry Survey ..................................... .... 21.2.1 Purpose ...................................... 21.2.2 Requirement .................................. 21.2.3 Technical Approach ........................... 21.2.4 Data Sources ................................. 31.2.5 Industry Survey Products ..................... 3

2 .0 Overview ............................................... 52.1 Search Methods ...................................... 52.2 Document Retrieval .................................. 6

3.0 Health and Usage Monitoring Systems .................... 73.1 Engine Performance Assurance Monitoring System

(EPAMS) - Howell Instruments, Fort Worth, TX ........ 73.2 Helicopter Pilot's Emergency Situation Advisor

(H/PESA) - Honeywell, Defense Avionics Division ..... a3.3 Engine Diagnostic Expert System (HELIX) -

Sikorsky Aircraft Division, United TechnologiesCorporation ......................................... 8

3.4 Intelligent Fault Isolation Procedures (IFIP) -Sikorsky Aircraft Division, United TechnologiesCorporation ................................. 8

3.5 Aircraft Integrated Monitoring System (AIMS) andIntegrated Health and Usage Monitoring System(IHUMS) - Bristow Helicopters Ltd. and PlesseyAvionics, London, UK ................................... 9

3.6 Power Analyzer and Recorder (PAR) - TeledyneAvionics, Charlottesville, VA ...................... 9

3.7 Rotor Track and Balance System (ROTABS) - Vibrc-Meter Company, Torrance, CA ........................ 9

3.8 COMPASS - Rolls-Royce/SD-SCICON, UK ................. 93.9 Expert Maintenance Troubleshooter (XMAN) - Systems

Control Technology, Inc., Palo Alto, CA ............. 103.10 Advanced Avionic Architecture Maintenance/

Diagnostic Assessment (AAM/DA) - Bell HelicopterTextron, Fort Worth, TX ............................ 10

3.11 Engineering Technical Analysis and Design System(ETADS) - Bell Helicopter Textron, Fort Worth, TX...10

3.12 Intelligent Maintenance Expediter and Training AidSystem (IMETS) - Bell Helicopter Textron,Fort Worth, TX ...................................... 10

3.13 Vibration, Structural, Life, and Engine DiagnosticSystem (VSLED) - Bell Helicopter Textron,Fort Worth, TX...................................... 11

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3.14 Light Helicopter - Integrated Diagnostics(LH ID) - Bell Helicopter Textron, Inc., FortWorth, TX ...... . ........................ * 1

3.15 Generic Integrated Maintenance and Diagnostics(GIMADS) Program - General Dynamics(Prime Contractor), Bell Helicopter Textron(Subcontractor) .................................... 1

3.16 TRENDKEY - Trendkey Inc., West Chester, PA .......... 123.17 Thrust Management System (TMS) - Safe Flight

Instruments, White Plains, NY ....................... 123.18 Engine Monitoring System Computer (EMSC) - AMETEK

Aerospace Products, Wilmington, MA .................. 123.19 Computer Aided Diagnostic System (CADS) -

Teknowledge Inc.; LCdr. Thomas J. Gadzala, NavalPostgraduate School, Monterey, CA ................. 12

3.20 Enhanced Diagnostic System (EDS) - McDonnellDouglas Helicopter Co., Mesa, AZ .................... 13

4.0 Technologies ................................ ...... 154.1 Integrated Diagnostics ............................ 154.2 Artificial Intelligence ........................... 164.3 Debris Monitoring ................................... 164.4 Vibration Analysis .................................. 17

5.0 Conclusions .............................................. :9

List of Acronyms .............................................. 21

Appendix A Documents Index .................................. A-1

Appendix B Health and Usage Monitoring Systems Summary ...... B-1

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1.0 INTRODUCTION

This report describes the work performed on the Federal AviationAdministration (FAA) Health and Usage Monitoring SystemsCertification Requirements project. This report includes a briefdescription of 20 health and usage monitoring systems. Itfurther includes abstracts of 90 documents pertinent to healthand usage monitoring technology. These 90 documents areorganized into 4 categories that are related to applications.

The overall goal of the effort described herein was thedevelopment of information to support FAA rotorcraftcertification requirements. The technical effort was dividedinto two tasks: a literature search and an industry survey ofongoing efforts involving technology for monitoring both healthand usage of critical rotorcraft flight components.

1.1 LITERATURE SEARCH

1.1.1 Purpose

The purpose of this task was to conduct a technical literaturesearch of health and usage monitoring technology. The searchconcentrated on military and civilian efforts in the developmentof automatic systems to monitor the performance and calculate thehealth of helicopter systems. The ultimate goal was to providethe information necessary to develop certification requirementsfor health and usage monitoring equipment.

1.1.2 Reauirement

The requirement addressed in this first task was to assist theFAA in developing a better understanding of what is beingdeveloped by industry to support helicopter engine and airframehealth and usage monitoring. An assessment was made of thematurity of these systems to support airworthiness accreditationand certification.

1.1.3 Technical Aoproach

An extensive literature search of military and civilian librarieswas conducted to define a list of existing and developing healthand usage monitoring systems for helicopter and fixed-wingaircraft. Utilizing the resources of the National TechnicalInformation Service (NTIS) and other technical databases,computer assisted searches were performed using a "key word incontext" approach to locate abstracts on technical papersdescribing these systems. The abstracts of over 1,000 reportswere analyzed, and a determination was made on which documentsshould be reviewed in their entirety. These documents were thenordered and reviewed in detail. A list was compiled of allsystems, manufacturers, key personnel, and technical evaluationsof the maturity of each system. This list was used as thestarting point for the industry survey.

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1.1.4 Data Sources

Data sources included the following:

a. NTIS,b. SCT technical library,c. DIALOG (an on-line database search service), andd. Trade journals on health usage and monitoring systems.

1.1.5 Literature Search Products

A comprehensive list of articles, publications, technicaldescriptions, and technical evaluations pertinent to helicopterhealth and usage monitoring systems is being provided to the FAA.An evaluation of the applicability of each system is alsoprovided.

1.2 INDUSTRY SURVEY

1, 2.1 P~M2E

The purpose of the industry survey task was to determine whichindustrial firms are participating in the development of healthand usage monitoring systems and to collect additionalinformation on specific health and usage monitoring systems underdevelopment.

1.2.2 feauireient

The requirement for the industry survey task was to conduct acomprehensive search of military and industrial sources of healthand usage monitoring systems. The search included obtaininginformation such as who are the participating firms, who are theK 9 personnel, what aspects of the technology are mature and whatare the key issues that need to be addressed to developcertification criteria.

1.2.3 Technical Auoroach

The list of firms developed in the literature survey task wasused as the initial source of locating industrial sources. Aquestionnaire on the relevant issues surrounding health and usagemonitoring systems was created. The questionnaire was reviewedand approved by the FAA prior to being mailed. The questionnaizeresults are analyzed and compiled in a separate report for FAAuse.

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1.2.4 Data Sources

The data sources used consisted of industrial firms participatingin the development of health and usage monitoring systems. Thesefirms were identified in the literature survey task and throughsecondary contacts.

1.2.5 Industry Survey Products

A listing of company names, addresses, key personnel, phonenumbers, and a description of the health and usage monitoringwork being accomplished is being provided to the FAA.

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2.0 OVERVIEW

This report covers the results of the health and usage monitoringliterature search. It describes the search methods, the resultsof the search, and summarizes the analysis of the documents thatwere reviewed in detail. A list of acronyms that are usedthroughout this report and in the documents is included at theend of this report. Appendix A is a copy of the library indexwhich is included with the documents. Appendix B is a chartsummarizing the various diagnostic and health monitoring systemsthat have been researched. Some of these systems have alreadybeen developed and have transitioned to field use, others havenot made it past the prototype stage, and some are still indevelopment.

The majority of the systems that were reviewed addressed enginemonitoring or engine and drive-train monitoring. Very few paperswere found that addressed integrated diagnostics from the pointof view of monitoring and diagnosing total air-vehicleperformance or health. Most systems monitored only a singleparametric function, such as vibration, oil analysis, enginehealth, etc.

The selection of documents was not limited to helicopter systems,because a significant amount of work has been accomplished infixed-wing aircraft diagnostic systems as well as air-breathingand rocket engine systems.

in particular, there is a wealth af information on diagnosticsystems within the space shuttle main engine development effort.The space shuttle main engine is the first operational liquidrocket engine developed for reuse. Because of the potential forcatastrophic consequences associated with a failure during groundtesting and in-flight operation, there has been considerable.emphasis on the development tf sophisticated monitoring systems.Therefore, several documents are included that report on effortsin this area.

The increased application of artificial intelligence technology,in particular the use of expert systems, shows considerablepromise as new monitoring and diagnostic applications aredeveloped. Several of the articles that were reviewed predictthat artificial intelligence technology has the potential todeliver significant advances in productivity and accuracy inmonitoring systems.

2.1 SEARCH METHODS

In addition to manual library searches and review of periodicalsand trade journals, use was made of automated library searches.These automated services facilitate the search of large databasesusing a common set of key words and phrases. Two major services

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were used: NTIS and DIALOG. The American Institute ofAeronautics and Astronautics library was also a major source foracquiring copies of the documents. Numerous commercialpublications such as Rotor and Wing International, Avionics,Aviation Equipment Maintenance, Aerospace Engineering, and theHelicopter Association International's 1990 Heliconter Annualwere also used.

Over 1,000 abstracts were reviewed on the NTIS and DIALOG systemsusing a combination of keywords and acronyms from the followinglist:

Condition Monitoring Helicopter EDSDiagnostics Integrated Diagnostics EMSDiagnostic Systems Prognostics FDREngine Monitoring Rotorcraft HUMSEngine Trending Trending ITEMSExpert Systems Usage Monitoring OCMHealth Monitoring TEMS

In addition to the selected keywords, the computer search wasrefined by limiting the documents to those published in theUnited States or published later than 1985. Without narrowirgthe search in this manner, the analysts were presented withthousands of documents to review, many of which had littlerelationship to the desired subject.

2.2 DOCUMENT RETRIEVAL

As a result of the literature survey, 90 documents, which arecatalogued in appendix A, have been acquired. The index inappendix A contains an abstract for each document.

Many of the documents contain information on more than one aspectof monitoring systems or address more than one area. For ease ofreview, the documents have been divided into the following fivesubject categories:

o Helicopter Diagnostics,o Other Aircraft Diagnostics,o Rocket Engine Diagnostics,o Technology, ando General.

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3.0 HEALTH AND USAGE MONITORING SYSTEMS

There is a distinct difference between health monitoring andusage monitoring systems. Although both rely on the collectionof parametric data, the health monitoring system performs theanalytical task of making a determination relative to theperformance of the system and its ability tc continue to performthe intended function. A usage monitoring system, on the otherhand, merely measures the consumption of life by one or morecomponent in terms of total time accumulated, time at a certainpressure or temperature, number of thermal cycles, or some othercalculable parameter. Usage monitoring data is normallyprovided to a ground processing system and is used to predictscheduled maintenance or the removal of a component when itreaches the end of its useful life.

Fealth monitoring systems, often referred to a. diagnosticsystems, fall into several categories. They may be in-flightmonitors or ground-based processors of data that are collected inflight. They may be systems that advise the operator (pilot) ormaintenance technician of the status of the system and/orrecommend action to be taken. In some instances, healthmonitoring systems are used to control the operation of thesystem (i.e., limit operation or shut the system down). Themajority !f health monitoring systems on manned vehicles normallyperform in the former mode of operation, that is, advise theoperator of a failure, impending failure, or recommended action.The action is left to the operator.

Appendix B is a list of health and usage monitoring systems thathave been reviewed as part of this study. The chart includes themajor characteristics of each system and indicates whether theypertain to helicopter or fixed-wing, usage or health monitoring,airborne or ground systems, and wheter or not they utilizeartificial intelligence technology. The cahrt also includes asubjective evaluation of the maturity of each system. Thefollowing paragraphs give a brief summary of each of the majorsystems that were surveyed.

3.. ENGINE PERFORMANCE ASSURANCE MONITORING SYSTEM (EP AS) -HOWELL INSTRUMENTS, FORT WORTH, TX

EPAMS is a mature system that is flying on a variety of fixed-wing and rotary, military and civilian, foreign and domesticaircraft. AS the name implies, it is primarily a monitoring anddata collection system. It accumulates life usage, includingexceedence history and provides a trending base for groundanalysis. It is used to support on-condition maintenance andengine life management. An additional vibration option isavailable. As a proven device, it has seen wide application.

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3.2 HELICOPTER PILOT'S EMERGENCY SITUATION ADVISOR (H/PESA) -HONEYWELL, DEFENSE AVIONICS DIVISION

H/PESA, a development/demonstrator system, is an emergencyadvisory system that not only displays information, but analyzes,evaluates, and recommends actions to the operator (pilot).H/PESA uses expert systems technology. The expert systeminterprets the state of the system (helicopter) and records it ina knowledge base. Hypotheses are formed summarizing the state ofthe system. Typical hypotheses could include "engine failureimminent" or "tail rotor failure." From these hypotheses, thenext step is for the expert system to recommend a "survival plan"for recovering from the emergency. This inferencing process isiterated to examine all states of the system and correlate themwith "survival plans" according to a predefined set of rules.The final step would be a single survival plan that would berecommended to the operator. This is the type of system thatrequires considerable research, testing, prototyping, anddevelopment. It will require significant interaction betweendevelopers, engineers, and operators before it is commonplace infuture aircraft.

3.3 ENGINE DIAGNOSTIC EXPERT SYSTEM (HELIX) - SIKORSKYAIRCRAFT DIVISION, UNITED TECHNOLOGIES CORPORATION

HELIX is a developmental program that diagnoses failures in theengine from sensor data, using the knowledge of the system'sfunctions in its database. Information on this program islimited; however, additional information was requested fromSikorsky during the industry survey.

3.4 INTELLIGENT FAULT ISOLATION PROCEDURES (IFIP) - SIKORSKYAIRCRAFT DIVISION, UNITED TECHNOLOGIES CORPORATION

Sikorsky identifies IFIP as a follow-on program to HELIX.General information indicates that IFIP will be capable ofguiding maintenance personnel through a diagnostic procedure tothe faulty component by bringing to bear encoded knowledge aboutthe system's normal function, as well as probabilities of-failure, previous field experience, and component interactions.Sikorsky claims that fielded applications have shown as much as a40 percent reduction in the manhours required to fault isolate,

- thus improving availability and supportability. In conjunction'with IFIP, Sikorsky has developed a portable maintenance aid(PMA) to improve maintainability and supportability. The PMA-combines an expert system with the aircraft log book, maintenancerecors, and the technical manual.

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3.5 AIRCRAFT INTEGRATED MONITORING SYSTEM (AIMS) AND INTEGRATEDHEALTH AND USAGE MONITORING SYSTEM (IHUMS) - BRISTOWHELICOPTERS LTD. AND PLESSEY AVIONICS, LONDON, UK

AIMS and IHUMS comprise a joint effort by BHL and PlesseyAvionics to develop a system specifically for helicopters thatsatisfies the new British CAA legislation on flight datarecorders which becomes mandatory in February 1991. The resultof this effort will be a system which integrates both health andusage monitoring to meet CAA requirements. This work, althoughbeing done in the UK, is pertinent to the FAA health and usagemonitoring project.

3.6 POWER ANALYZER AND RECORDER (PAR) - TELEDYNE AVIONICS,CHARLOTTESVILLE, VA

This is a mature unit that is in use on fixed-wing aircraft andhelicopters. Its primary purpose is to compute power assurancechecks, detect/record/advise operators of exceedences, and act asa usage monitor. It records engine parameters, including torque,rotor speed, airspeed, fuel flow, temperature, and altitude.Although it is not in the category of a diagnostic system, it isa relatively inexpensive device that could be used to providenecessary information when cost is a factor.

3.7 ROTOR TRACK AND BALANCE SYSTEM (ROTABS) - VIBRO-METERCOMPANY, TORRANCE, CA

ROTABS is a computer-based program designed to optimizehelicopter rotor setup in order to minimize damaging vibration.The ROTABS system is comprised of three modules: sensor array,signal acquisition and processing, and a laptop microcomputer.After completion of data acquisition, the system computes thebest possible set of maintenance actions based on modelled rule-based criteria and past experiences. The result of thesecomputations is a set of maintenance instructions to thetechnician.

3.8 COMPASS - ROLLS-ROYCE/SD-SCICON, UK

COMPASS is a system developed by Rolls-Royce and SD-SCICON toprovide upline operators with a software shell to perform enginetrending and diagnosis. COMPASS provides the user with a varietyof data displays and performs data smoothing and trendingfunctions. It is designed to be able to run software fromvarious engine manufacturers under one common system. COMPASS iscurrently in use with Lufthansa, British Airways, and TWA.

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3.9 EXPERT MAINTENANCE TROUBLESHOOTER (XMAN) - SYSTEMS CONTROLTECHNOLOGY, INC., PALO ALTO, CA

XMAN is a personal computer-based application of an expertmaintenance and diagnostics tool for the flight line mechanic.It integrates performance and maintenance history data frommultiple databases to diagnose detected malfunctions. As aground-based system, it relies cn data from an on-board processoras well as other data sources, including maintenance historyfiles, oil analysis data, and engine configuration data. Thesystem implements the fault isolation trees that are provided bythe engine manufacturers and derives facts from the variousdatabases to fault isolate reported malfunctions. It has beenfielded on the A-10 TF-34 engine and the AV8B F404 engine.

3.10 ADVANCED AVIONIC ARCHITECTURE MAINTENANCE/DIAGNOSTICASSESSMENT (AAM/DA) - BELL-HELICOFTER-TEXTRON,FORT WORTH, TX

AAM/DA is an Army program to establish maintenance and diagnosticdesign criteria for future advanced avionic architectures.Specific design criteria will be defined for helicopter conditionmonitoring and fault detection/isolation. The intent is toinfluence the design e'.rly so that maintenance data processingrequirements and capabilities for airborne and ground modes willbe incorporated. This effort is based on the Tri-Service JointIntegrated Avionic Working Group (JIAWG) definitions of commonmodules and common avionic baselines (CAB). The results of thisanalysis will be used to guide condition monitoring and faultdetection isolation design efforts within the military community.

3.11 ENGINEERING TECHN!CAL ANALYSIS AND DESIGN SYSTEM (ETADS) -BELL HELICOPTER TEXTRON, FORT WORTH, TX

ETADS is a concurrent engineering tool development program withthe overall goal of providing engineers with tools to quickly andaccurately produce designs for diagnostics systems. It isincluded in this study because of Belles use of the system todevelop a library structure in order to capture the wealth ofdiagnostics data produced and collected by Bell HelicopterTextron. This will permit the previously collected data to bequickly accessed by design engineers. FAA engineers should beaware of this database as they work through the certificationprocess for helicopter diagnostic applications.

3.12 INTELLIGENT M.INTENANCE EXPEDITER AND TRAINING AID SYSTEM(IMETS) - BELL HELICOPTER TEXTRON, FORT WORTH, TX

IMETS is a Bell Helicopter Textron in-house research anddevelopment program to develop a personal computer tool thatcontains expert knowledge about fault diagnosis in helicoptersystems. The goal is to reduce maintenance time by providing

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fault location more rapidly and by providing a list of tools andequipment required for repairs. As a diagnostic aid, it isdesigned to provide better diagnostics that will ultimatelyresult in fewer cases of maintenance error. This ground systemwill require data collection from airborne processors or othertest equipment.

3.13 VIBRATION, STRUCTURAL, LIFE, AND ENGINE DIAGNOSTIC SYSTEM(VSLED) - BELL HELICOPTER TEXTRON, FORT WORTH, TX

VSLED is a developmental system that is part of the centralintegrated checkout (CIC) system on the V-22 tiltrotor aircraft.The name suggests the functions that it performs, i.e., monitorsvibration and temperatures, keeps tabs on structural life, andrecords events in the engine. It was designed to support on-condition maintenance (OCM) as a diagnostic tool for the first. &chanic. As a state-of-the-art system, it communicates cn

the V-22's dual-redundant 1553 data bus. It processes and storesdata from three separate sources: the data bus, the fullauthority digital electronic controls (FADECs), and theaircraft's nacelle interface units. The future of the V-22 willperhaps dictate the future of VSLED; however, the system haspractical a plication on future helicopter systems also.

3.14 LIGHT HELICOPT2R - INTEGRATED DIAGNOSTICS (LH ID) - BELLHELICOOTER TEXTRON. INC., FORT WORTH, TX

LH ID is a developm .nt program for the Army's next generationlight helicopter. The integrated diagnostics will use advancedavionic architectures to develop a cost effective system thatmeets supportability requirements and goals. The final designwill address four major areas: an aircraft condition monitoringsystem, an aircraft managemenL subsystem, a mission equipmentpackage diagnostics subsystsrn, and an aircraft prognosticsfunction. This is being develor3d in Bell Helicopter Textron'slaboratories in Fort Worth, TX. Tnis program warrants furtherinvestigation as it develops.

3.15 GENERIC INTEGRATED MAINTENANCE AND DIAGNOSTICS (GIMADS)PROGRAM - GENERAL DYNAMICS (,RIME CONTRACTOR), BELLHELICOPTER.TEXTRON (SUBCONTRACTOR)

GIMADS is an. ongoing development effort sponsored by the AirForce Aircraft Systems Division at Wright-Patterson Air ForceBase, OH. There are eight contractors participating in thisprogram to develop and institutionalize a step-by-step structuredsystem engineerirg time-phased process for integrateddiagnostics. As a design effort, it %ill include considerationof the latest technologies, innovative design approaches,integrated logistics support and verification and proof ofconcept. The results will be a Mil-Standazd that delineates the

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process and an Air Force Guide Specification. It will be

applicable to helicopter and fixed-wing diagnostic systems.

3.16 TRENDKEY - TRENDKEY, INC., WEST CHESTER, PA

TRENDKEY is basically an instrument that is advertised as apilot's helper, a systems monitor, a fuel management system, anair data computer, and as backup instrumentation. It is includedin this survey because of its monitoring function and ability tomeasure and record exceedences. Although not a particularlysophisticated device, it also is an economic alternative in thelow-cost aircraft market to provide a limited degree of systemmonitoring.

3.17 THRUST MANAGEMENT SYSTEM (TMS) - SAFE FLIGHT INSTRUMENTS,WHITE PLAINS, NY

TMS is an on-board computer that accepts information fromexisting air data systems, engine instruments, mode logic, andaccessory computers and it provides outputs to instruments,annunciators, and automatic throttles. The TMS is programmedwith the certified engine operating envelope and provides cockpitadvice when the envelope is exceeded. The pilot receives powersetting guidance on his flight director slow-fast indicator. Ifautothrottles are installed, TMS can implement power settinginformation by driving throttles directly.

3.18 ENGINE MONITORING SYSTEM COMPUTER (EMSC) - AMETEK AEROSPACEPRODUCTS, WILMINGTON, MA

The EMSC is in operation on more than 1,000 F-16 aircraft. Thesystem processes information for exceedence monitoring and faultisolation. It supports vibration analysis, trend monitoring, andparts life tracking. Engine parameters, in addition to cockpitadvisory notices and flightline go/no-go indications, areprovided to the ground mechanic through a data display andtransfer unit. This is a mature system and has applicability tohelicopter operations.

3.19 COMPUTER AIDED DIAGNOSTIC SYSTEM (CADS) - TEKNOWLEDGE,INC.; LCDR. THOMAS J. GADZALA, NAVAL POSTGRADUATE SCHOOL,MONTEREY, CA

CADS is the result of a study undertaken to demonstrate thefeasibility of applying expert system technology to the Navy's H-46 helicopter maintenance process. A microcomputer-basedprototype known as a computer-aided diagnostic system (CADS) wasdeveloped for this purpose. The prototype CADS was developedutilizing the M.1 knowledge-based system development tool byTeknowledge, Inc. There is no indication at this time that thesystem has gone beyond the prototype stage.

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3.20 ENHANCED DIAGNOSTIC SYSTEM (EDS) - MCDONNELL DOUGLASHELICOPTER CO., MESA, AZ

EDS is McDonnell Douglas' system for structural monitoring on theAH-46 helicopter. Although it is a multi-functional system, oneof the primary purposes of EDS is to obtain operational loadsdata. The system functions in two modes: 1) on-board recordingand diagnostics, and 2) ground analysis. The referenced documentprimarily addresses the structural monitoring aspects of thesystem.

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4.0 TECHNOLOGIES

Advances in the areas of avionics, propulsion, sensors, andcomputer technology have had significant impact on thedevelopment of health usage and monitoring systems. We havecome a long way from hanging analog reading devices on aircraftsystems and copying down data for later analysis. New sensortechnology has made use of fiber optics, micro-miniaturecomponents, strain gages, and laser technology common place incollecting data. Improvements in cooling, shock mounting, andrugged packaging have permitted placing sensors and processors inpreviously inaccessable places on the aircraft. Perhaps the mostsignificant advances have been in the speed of processors and theincrease in on-board data storage. The combination of all ofthese factors has facilitated in-situ capture, processing, andrecording of diagnostic data. The operational impact ranges fromthe in-flight collection of data for ground processing toimmediate pilot notification of subsystem performance and, in theultimate case, to actual control of a subsystem base on real-timeanalysis.

The use of artificial intelligence techniques, particularlyexpert systems, will continue to expand in both airborne andground diagnostic systems. Several of the new technologies arediscussed in the following paragraphs to give the reader an ideaof what is taking place as one considers the certification of newdiagnostic and monitoring systems.

4.1 INTEGRATED DIAGNOSTICS

Historically, diagnosis of electrical, mechanical, and propulsionsubsystems has been accomplished at the subsystem level, and onlyfor that subsystem. That kind of approach has naturally led tothe proliferation of different types of diagnostic systems and,often, duplication of effort. Avionics subsystems were thefirst to integrate diagnostic functions among the various avionicsubsystems such as communications, navigation, weapons delivery,electronics countermeasures, etc. The results of avionicsdiagnostics were presented on avionics status panels, and later,as the data bus concept developed, the information was recordedand analyzed in on-board processors. With the advent ofintegrated flight controls, digital engine electronic controls,and fly-by-wire aircraft such as the F-16, all of the diagnosticinformation has become available on a common data bus. Anintegrated approach to diagnostics implies that each of theaircraft subsystems generate critical information that isimportant not only to the pilot, but to the maintainers of theaircraft. New aircraft such as the Advanced Tactical Fighter andthe Stealth Bomber take into account-the fact that diagnostics,re a function that envelopes the entire aircraft, and health andvsage monitoring systems are being developed in that light.

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Aircraft now in the design and development cycle will addressdiagnostics from a systems approach. The challenge isintegrating diagnostics on existing aircraft. That is perhapsbeyond the scope of this study, but the technology associatedwith integrated diagnostics will surely need to be addressed inthe certification process for new diagnostic systems.

4.2 ARTIFICIAL INTELLIGENCE

A new area of interest in engine monitoring is the use of oneaspect of artificial intelligence, expert systems. As mentionedin the above paragraph, the use of a computer to diagnose troublein avionics systems is well established. The use of automatictest equipment (ATE) and built-in test equipment (BITE) is wide-spread throughout avionics systems. The use of expert systemsinvolves capturing the "expert" knowledge of human engineers andtroubleshooters and committing that knowledge to a set of rulesthat can be quantified and stored in the computer. The rulesmust emulate the knowledge of a wide range of human experts andfunction with the speed of today's modern computers. The expertsystem receives data from the sensors in an aircraft orsubsystem, stores the data, converts the data to knowledge orfacts describing the condition of the subsystem, and applies therules of the "expert" to determine or recommend an action. Mostof today's expert systems applications keep the human "expert" inthe loop. As expert systems continue to be developed and gainconfidence, their use will rapidly expand to all areas ofdiagnostics and maintenance. The particular advantage of thesesystems is their ability to absorb vast amounts of input factsand make a consistently accurate decision in a split second.Artificial intelligence technology, most notably the use ofexpert systems, will play an increasing role in the developmentof health and usage monitoring systems.

4.3 DEBRIS MONITORING

The role played by particulate analysis of lubricating fluids inengines has been limited in the past to analyzing the oil on theground# after the fact. The oil analysis results were normallyused in conjunction with other indicators to assess the conditionof mechanical systems. Recent developments allow, for the firsttime, microprocessor-based on-board systems to detect and collectsignificant data during system operation. While the role of thequantitative debris monitor (QDM) remains essentially the same,the speed and accuracy at which it can accomplish its functionpermits the correlation of seemingly unrelated symptoms toconfirm an impending or actual failure. The reliance on real-time debris monitoring technology as an input to integrateddiagnostic systems will also increase as new aircraft systems aredesigned.

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4.4 VIBRATION ANALYSIS

As with debris monitoring technology, the improvements in sensorsand on-board processing capability provide one more source ofdata for the diagnostic systems. In the area of vibration,digital processing can precisely measure engine, drive-train, andaccessory vibration. Previous analog systems with one or morefixed data bands were subject to uncertainty as to whether thedata was real or a false alarm. Digital systems virtuallyeliminate that ambiguity. Structural integrity programs willsurely benefit from the results of improvements in this area oftechnology. The benefits of inputting this type of data intointegrated diagnostics systems will include more accurateordering of spare parts, more operational spare engines, and areduced number of spares. As an additional data input to adiagnostic system, vibration monitoring information will supportthe on-condition maintenance concept. This type of informationwill certainly reduce the number of catastrophic failures and theresultant damage associated with secondary failures.

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5.0 CONCLUSIONS

The purpose of this task was to conduct a technical literaturesearch of health and usage monitoring technology. Over 1,000abstracts were reviewed and 90 documents were selected related tohealth and usage monitoring systems. Those areas that offersignificant relevance in new and developing diagnostic systemshave been highlighted.

The most obvious conclusion is that future helicopter diagnosticsystems will not be limited to individual subsystems. They willmost likely address the aircraft as a system and report on thestatus or condition of all subsystems. More processing will beconducted on the aircraft as new sensors, processing capability,and storage are added to the airframe. More data will becollected and passed on to ground processors for furtheranalysis, trending, comparison with fleet "norms," and for use inground troubleshooting. Artificial intelligence (expert systems)will continue to grow in importance and use, both in aircraft andground systems.

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LIST OF ACRONYMS

AAM/DA Advanced Avionic Architecture Maintenance/DiagnosticAssessment (Bell)

ACAP Advanced Composite Aircraft ProgramAIAA American Institute of Aeronautics and AstronauticsAIMS Aircraft Integrated Monitoring System (Bristow, Plessey

Avionics)ARIA Advanced Reconfigurable Integrated ArchitectureART2 Adaptive Resonance TheoryASEE American Society for Engineering EducationASME American Society of Mechanical EngineersATE Automatic Test EquipmentBITE Built-In Test EquipmentBUCS Backup Control SystemCAA Civil Aviation AuthorityCAB Common Avionic BaselineCADS Computer Aided Diagnostic System (Gadzala, NPG)CALS Computer-Aided Acquisition and Logistic SupportCAM Content Addressable MemoryCERWAT Center of Excellence for Rotary-Wing Aircraft

Technology (Georgia Institute of Technology)CIC Central Integrated Checkout SystemCMS Condition Monitoring SystemCVR/FDR Cockpit Voice Recorder/Flight Data RecorderDALT Density AltitudeDARPA Defense Advanced Research Projects AgencyD&CM Diagnostic and Condition MonitoringEDS Enhanced Diagnostic System (McDonnell Douglas)EGT Exhaust Gas TemperatureEISE Extendable Integrated Support EnvironmentEMS Emergency Medical ServiceEMSC Engine Monitoring System Computer (Ametek)EPAMS Engine Performance Assurance Monitoring System (Howell

Instruments)ETADS Engineering Technical Analysis and Design System (Bell)FAA Federal Aviation AdministrationFADEC Full Authority Digital Electronic ControlFCM Flight Condition MonitoringFDR Flight Data RecorderGIMADS Generic Integrated Maintenance and Diagnostics (General

Dynamics)HARP Helicopter Airworthiness Review Panel (CAA)HHC Higher Harmonic ControlHMS Health Monitoring SystemH/PESA Helicopter Pilot's Emergency Situation Advisor

(Honeywell)HELIX Engine Diagnostic Expert System (Sikorsky)HUMS Health and Usage Monitoring SystemIFIP Intelligent Fault Isolation Procedures (Sikorsky)IHUMS Integrated Health and Usage Monitoring System (Bristow,

Plessy Avionics)

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IMETS Intelligent Maintenance Expediter and Training AidSystem (Bell)

INTERFACE Integrated Reliable Fault-Tolerant Control for EnginesITEMS Integrated Turbine Engine Monitoring SystemJIAWG Joint Integrated Avionic Working GroupLH ID Light Helicopter - Integrated Diagnostics (Bell)LHX Light Helicopter Experimental ProgramLRU Line Replacement UnitN1 Turbine Engine Gas Producer SpeedN2 Power Turbine SpeedNASA National Aeronautics and Space AdministrationNAVAIR Naval Air Systems CommandNEOF No Evidence of FailureNp/Nr Propeller Speed/Rotor SpeedNTIS National Technical Information ServiceOAT Outside Air Temperature0CM On-Condition MaintenancePALT Pressure AltitudePAR Power Analyzer and Recorder (Teledyne)PC Personal ComputerPI Parameter IdentificationPMA Portable Maintenance AidQDM Quantitative Debris MonitorRAF Royal Air ForceROTABS Rotor Track and Balance System (Vibro-Meter)SAE Society of Automative EngineersSCT Systems Control Technology, Inc.SFC Specific Fuel ConsumptionSSME Space Shuttle Main EngineTEMS Turbine Engine Monitoring SystemsTMS Thrust Management System (Safe Fliqht Instruments)VLSI Very Large Scale IntegrationVSLED Vibration, Structural, Life, and Engine Diagnostic

System (Bell)VTOL Vertical Takeoff and LandingVTRS Visual Technology Research SimulatorXMAN Expert Maintenance Troubleshooter (SCT)

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APPENDIX A

DOCUMENTS INDEX

A. 1 BZLZCTOU DUJDOSTCSDCC. NWZ: 1

!ZTLZ: AIMS for Helicopters

AU!M: D. Jesse, Bristow Helicopters LimitedD.W. Barr, Plessey Avionics

IDLZSM: DLR, Institut fur Flugfuhrung - Proceedings of 15thAIMS Symposium

D0 =: September 1909

DOC. T!ZV: Symposium Paper

ABSTRACT: Helicopters differ from fixed-wing aircraft in that most of theflight safety critical components cannot be duplicated. In order to improveflight safety and to reduce opera'cing costs, an AIMS system specificallydesigned for helicopters is needed. This joint paper between BristowHelicopters Ltd. and Plessey Avionics considers the current progress on HUMsystems, and the need to satisfy the now Civil Aviation Authority (CAA)legislation on flight data reccrders for helicopters which becomes mandatoryin February 1991. The result is a joint development programme whichintegrates both functions and provides proven hardware in time for thelegislation, and is of practical use to the operators.

DOC. bWU: 2

TIZLK: Airborne Integrated Monitoring System

AUTOR: A.H. Neubauer, Jr., Teledyne Controls

PRULM : Unknown

DTN: Unknown

DOC. TMz: Conference Paper

WIRAC?: This paper addresses the goals and issues associated with on-boardmonitoring techniques and suggests approaches for dealing with them. Bothinput and output signal interface goals will be discussed# along with themicroprocessor and memory devices necessaxy to implement a viable monitoringsystem.

The major goal for input and output interfaces is to achieve a workable systemthat operates completelyi in the digital domain. Although this is not alwayspractical, the achievement tf such a goal will reduce system complexity andaircraft wiring. For memory and recording, the goal is to inplement costeffective, solid-state, nonvolatile devices that can provide error free andlong lasting storage of data while withstanding the hostile environment. Thegoal for computer technology is to make maximum use of existing devices but toretain the flexibility necessary to accept new, high capacity da-icos as theycome on the market.

The central integrated checkout system being implemented on the V-22 Ospreytiltrotor aircraft will be used as the example of current technology.

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DOC. NOUB: 3

ZTI=: Another Day with an EMS Mechanic

aUMMOl: D.L. Bonney, St. Louis Helicopter Airways

PUBLTSER: Journal of Air Medical Transport

Da=Z: December 1989

DOC. TYPZ: Journal Article

AS!RACT: This article chronicles a typical workday for an emergency medicalservice (EMS) mechanic. He performs one zone of the Approved AircraftInspection Program on a BO-105 Messerschmitt-Bolkow Blohn helicopter.

DOC. NWMA: 4

TZTLZ: Application of Constraint Suspension Techniques to Diagnosisin Helicopter Caution/Warning System=

AV OR: G. Glenn, McDonnell Douglas Helicopter Company

PUBLS R: American Helicopter Society - National Specialists Meeting

DM': April 1988

DOC. T02: Conference Paper

ANST=: This paper describes research done at McDonnell Douglas HelicopterCompany in applying artificial intelligence techniques to the task of advisinga helicopter crew of events taking place in their aircraft subsystems.

As paort of the U.S. Army Apache EDS contract, a demonstrator ststem wasdeveloped that is capable of simulating multiplex bus traffic ofcautionlwarning related data, and invoking a diagnostic module upon detectionof an abnormal condition. Problem indicators ate prioritistd based onseverity and displayed on a simulated up-front cockpit display andmultifunction display. The demonstrator ateWtS to provide a diagnosis,where possible, and also provides advice about actions to be petfor ed inresponse to critical situations. Severe problems ae announced using an auralannunciator with digitally sampled stored Messcges. The diagnostic moduleutilizes a technique called candidate generation via constraint suspension toprune the list of suspected cotponents while diagnosing a failure. Constcaintsuspension is a form of model-based reasoning that allows faults. to bediagnosed by modeling tile intended correct behavior of the system andcozaring the outputs of the model with the true behavior of the system. Thistechnique, which was first investigated by Randall Davis at the ,assachusettsInstitute of Technolcgy under DARPA funding, shows potential for use as adiagnostic tool in gtound-based as well as airbo-ne systems.

A-2

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DOC. NWUZR: 5

TITLE: Automatic Engine Monitoring Field Installation and ReliabilityEvaluation Report

AUTHOR: B.M. Battles, Bell Aelicopter Textron

PUBLISHER: Helicopter Association International

DATE: July 1989

DOC. TYPE: Project Report

ABSTRACT: This report concludes an evaluation of automatic engine monitoringequipment, which began in November 1985. The final phase of the project was afield installation and reliability evaluation, during which equipment wasinstalled in operational aircraft, Semco Instruments was the only monitormanufacturer that met all the HAI requirements. Six attachments to the reportsummary give information on the operators and their aircraft, the fieldinstallations, the performance of each system, the systems' functions andparameters, the operators' comments, and other ancillary operators' com entsbeyond the scope of the evaluation.

DOC. NUMBER: 6

TITLE: Bell'l. Design Approach for Future RotorcraftMaintenarce/Diagnostics

AUTHOR: h. Franks, R. Samson, R. Patten, J. Emery; Bell HelicopterTextron

PUBLISHER: Amorican Helcopter Society - 46th Annual Forum

DATE: May 1990

D0C. T!PZ: Conference Paper

ABSTRACT: This paper describes an overview of programs under way at Bell inwhich advanced maintenance/diagnostics technology guidelines are beingdeveloped and applied in the engineering design process. Examples of company-sponsored work and contracted prograna ar- described, addressing therequirements fir near-term guidelfnes and thore leading into the next century.An overview cj a future specification being developed by the Air Force calledGIMADS is discussed, with emphasis given to fon; the mechanical systemsdiagnostics portion of the specification developmenat. Plans for Incorporating"lemsons learned" into Bell's computer-aided engineering aztivities arediscussed.

Examples of programs addressing onboard maintenance/diagnostics aids aresummarized, including health, usa-i/lifing, monitoring systems (HUMS) forcommercial helicoptegs, and the health monitoring system to be used on theV-22 Osprey. An overview of a study contract called advanced architecturemaintenance/diagnostic assessment .AAM/DA) is discussed. This program, fundedby the U.S. Army Aviation Applied Technology Laboratory; is studying advancedmaintei°dnce/diagnostics requirements and the development of guidelines forincorporating maintenance/diagnostics into advanced avionics architecture.

A-3

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DXC. NMMU: 7

TZILZ: CHC's High-Stakes Venture into Helicopter Maintenance

AUMB: H. McLean

RUDLZSrR: Rotor & Wing Interi:%tional

DM: April 1990

DOC. TY!Z: Magazine Article

hBSTkC!: Canadian Helicopters Corporat.on's (CHC) maintenance arm is theEnginaering Support Division. The diviiion began as Okanagan Helicopters, thelargest of the companies now part of CHC, and after a downturn in the early19809, the division now services customers throughout Canada and in 3ver adozen countries. The division's services include maintenance on the SikorskyS-61; engine overhauls on Allison 250 series, GE CT58, Pratt & Whitney PT6,Turbomeca Arriel and others; parts for all major helicopter models; overhaulon Bell and Aerompatiale components and accessories; avionics and instrumentservices; precision machine shop work, nondestructive testing; and majorairframe overhauls and rebuilds. International business accounts for about45% of the division's revenues. The division is targeting the CanadianDepartment of National Defense for future business.

DOC. RflMZ: 8

TXTLE: A Comprehensive Diagnostic System for the T800-APW-000 Engine

ACT=: A. Bilodeau, K.S. Collinge; Textron Lycoming

PUDLZTS : Unknown

D=: Unknown

DOC. TYi: Conference Paper

ARM=: in responing to U.S. Army requirements to improve LHX weaponsystem maintenance to the greatest extent possible, Textron Lycoming createdai advinced engine-mounted system for the TOOO-APW-aO0 gas turbine engine.Although named the engine monitoring system, it is much more than the nameimplies. It is a comprehensive diagnostic system which monitoras, diagnoses,and provides maintenance and repair instructions and mission data records.

This EMS leads diagnostic technology with its ability to continuously acquire,validate, monitor, analyze, recotd, and manage all engine paraeteors. The HSpLovides both flight and maintenance crew support with infornation on engineperformance, condition, operational history, maintenance requirements, repairinstructions, and logistic infomtion. With this informatior, automateddiagnosis, Maintenance, and repair can be accoplished in a timely manner.All of this information is available to flight and maintenance crews and tofleet data collection centers.

The system minimizes false diagnosis, reducing NEOF (No Evidence Of Failure)returns to depot. This is accomplished through the combination of automaticand semi-automatic diagnosis. The EHS maximizes engine availability,maintainability, reliability, and operability while it miaiizes engine lifecycle c03ss.

A-4

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DOC. NWMZ: 9

TZTLZ: Development of a Prototype H-46 Helicopter Diagnostic ExpertSystem

IDTHOR: T.G. Gadzala, Naval Postgraduate School

PUBLZSUR: Naval Postgraduate School

DAMZ: September 1987

DCC. TYPE: Master's Thesis Report

ABSTRACT: This study was undertaken to demonstrate the feasibility ofapplying expert system technology to the Navy's H-46 helicopter maintenanceprocess. A microcomputer-based prototype known as a computer-aided diagnosticsystem (CADS) was developed for this purpose. Given a helicopter electricalor hydraulic system discrepancy, the troubleshooter interacts with CADS tofind the cause. The prototype CADS was developed utilizing the M.1 knowledge-based system development tool by Teknowledge, Inc.

The complexity of helicopter systems diagnosis and inadequacies of themaintenance manuals often result in unnecessary removal of system components.The prototype CADS is intended to demonstrate that a fully developed system,containing all the formal and heuristic knowledge of H-46 diagnosticinformation, could eliminate these problems. Alao, such a diagnostic systemcould provide a comprehensive, stable diagnostic knowledge base, regardless ofpersonnel turnover.

This study includes a description of current helicopter maintenanceprocedures, and how the integration of CADS could improve this process. Alsoincluded are descriptions of expert systems and the M.1 knowledge-based systemdevelopment tool: how they work, and their applicability to structuredselection problem-solving. The development and testing strategies used forCADS are discussed in detail. Results, conclusions, and recormendations forfurther study are provided.

DOC. WNZ : 10

TIT: Development of a Structural Integrity Recording System (SIRS)for U.S. Army AH-1S Helicopters

ADMOR: J.G. Dotson, A.W. Kolb; Technology Incorporated

POWSf: Applied Technology Laboratory, AVRADCOM

DMZ: May 1982

DOC. TI Final Report

ASTRACT: A follow-on research and development program to implement astructural integrity recording system for the Army AH-IS helicopter wasconducted by developing a computer program to reduce recorded aircraft usagedata. The program, entitled fatigue damage assessment system, was designed torun on the AVRADCOM computer. An improved lift-link-mounted strain censor wasalso developed. The sensor was laboratory-tested and deemed ready for follow-on application testing in regard to monitoring helicopter gross weight, andtakeoff and landing detection.

A-5

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DCC. NUN=: 11

TxLZ: Diagnostic and Condition Monitoring (D&CM) System Assessmentfor Army Helicopter Modular Turboshaft Engines

IZTNOR: H.J. John; General Electric Company, Aircraft Engine Group

PUBLISEM: Applied Technology Laboratory, AVRADCOM

Dl=: October 1980

DOC. TYPZ: Final Report

ABSTRACT: Needs for and means of improving D&CM and troubleshooting tomodules and LRUS for the T700-GE-700 engine in Army environment were studied.Recommendations are: (1) Do not modify existing METS for modular faultisolation. However, do computerize the acquisition of the overall engineperformance data; (2) introduce the slave chip detector to the depot; (3)expand evaluation of the control system analyzer by Black Hawk companies; (4)support the development of degaussing chip detector; (5) initiate Phase I ofmultipurpose airborne D&CM system which combines performance, life, overtempand chip detector monitors; and (6) continue to acquire T700 field data anddevelop a method to quantify D&CM payoffs such as better engine availability.

DOC. NWUG: 12

TITLZ: EH-101 Cockpit Displays: Keeping It Plain and Simple

AUTHOR: S. Coyle

PUDMISBU: Rotor & Wing International

DM!3: May 1990

DOC. TYTZ: Magaziae Article

ASTACT: The electronic displays and software used in the EuropeanHelicopters Industries (EHI) EH-101 multipurpose helicopter confer severalmajor advantages: different end uses (military versus civil) have differentdisplay output: different flight modes (start-up versus cruise) also changemode; and different applications (low altitude versus high altitude) can havedifferent displays. The display and/or avionics can differ by installation(e.g. MIL-STD-1553B wiring versus ARNC 429 civil wiring), by switchselection, and be automatically based on sensor data. The advantages aremany, including uncluttered display for swift pilot reaction to emergencies,versatility for different helicopter configusations (military versus civil),and better maintenance records.

A-6

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DOC. NMBZR: 13

TITLU: Emerging New Technologies at Sikorsky Aircraft

hTHOR: Dr R.K. Shenoy, Research and Development Planning, SikorskyAircraft Division, United Technologies Corp.

PUBLISNER: Vertiflite

DA Z: March/April 1990

DC. TYPZ: Magazine Article

ABSTRACT: Currently Sikorsky Aircraft is adapting advances in electronicstechnology to make rotorcraft more reliable and competitive. Expert systemsand artificial intelligence, advanced simulation, and engineering automationtop the list of such emerging technologies and are briefly described in thisarticle. In addition to these areas, to counter the improvements in detectiontechnology, low observables are emerging as another technology of interest.Considerable investment and progress has been made at Sikorsky Aircraft in lowobservables technologies, which include radar signature control and infraredsignature control. Due to the nature of this subject, only a few details ofthe radar signature control technology will be discussed.

DOC. NOWR: 14

TZTLU: An Experimenter Operator Station for Helicopter FlightSimulator Research and Training

AUTHOR: T.A. Kaye, Bell Helicopter TextronL.M. Freeman, Aerospace Engineering, University of Alabama

PUBLISUER: AIAA

DAT!: 1989

DOC. TYll: Conference Paper

ABSTRACT: The increasing use of flight simulators for pilot training isprimarily driven by economic and safety considerations. A very laborintensive research effort is usually required in order to verify the basicassumption that the skills a pilot develops in the simulator are the same asthe skills required to fly the actual aircraft. Studies that demonstrate apositive transfer of learning to the pilot typically require human factorsresearchers to perform many repetitious and tedious tasks, particularly in ,hearea of data acquisition and statistical analysis.

A-7

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DOC. NMOM: 15

TITLZ: Expert Systems for Helicopter Pilots

AUTHOR: W. Shaneyfelt; Defense Avionics Systems Division, Honeywell

PUBLISmRR: Avionics

DA Z: January 1990

DOC. TYPZ: Magazine Article

ABSTRACT: The helicopter pilot's emerging situation advisor (H/PESA) is aprototype demonstration of a cockpit expert emergency advisory system. Thesystem displays, analyzes, and evaluates information, and reconuends actions.In addition to factual information, the knowledge base includes rules ofinference. The organization of the knowledge base was determined, in part, byexecution speed. During an in-flight emergency, a pilot cannot wait for anexpert system to go through a lengthy analysis. Speed gains have beenachieved by organizing rules in the knowledge base into a hierarchy.

DOC. NMMR: 16

TITL: Fixed-Gain Versus Adaptive Higher Harmonic Control Simulation

AUTHOR: LTC K.P. Nygren; Dept. of Civil & Mechanical Eng., U.S.Military AcademyD.P. Schrage; CERWAT/School of Aerospace Eng., Georgia Inst.of Tech.

PUBLISHR: American Helicopter Society

DATE: July 1989

DOC. TYPE: Journal Paper

ABSTRACT: A computer simulation of helicopter vibration reduction usinghigher harmonic control (HHC) is developed by incorporation of an HHC solutionprocedure in the dynamic system coupler program. The simulation can modelalmost any HHC control and identification scheme tested to date, includingstochastic control. The adequacy of fixed-gain as opposed to adaptive controlhas recently been in question. Both of these HHC methods are simulated insteady and constant-thrust maneuvering flight, as well as conditions ofincorrect transfer matrix initialization. The results indicate fixed-gaincontrol can adequately reduce vibrations for the helicopter madeled, as longas the flight condition is within about 20 knots of the flight conditions usedto calculate gains.

A-8

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DOC. NMMZR: 17

TITLE: A Full Authority Digital Electronic Control System for Multi-Engine Rotorcraft

AUTHOR: D. Petro; AVCO Lycoming Division I A.J. Gentile; ChandlerEvans Inc. A.B. Foulds; Hawker Siddeley Dynamics Engineering

PUBLISHER: The City University - 11th European Rotorcraft Forum

DATE: September 1985

DOC. TYPZ: Conference Paper

ABSTRACT: Conventional engine control systems for turbine-powered rotorcrafthave become increasingly complex in the process of striving for optimizedperformance of the power plant and aircraft. Traditionally, the only method ofachieving this goal was to increase the level of functional sophisticationwithin the control through nonelectronic techniques.

Using a proposed Royal Air Force (RAF) application as an example, this paperreviews the basic requirements and need for incorporation of a full authoritydigital electronic control system on an existing twin-engine militaryhelicopter. The unique selection process and component configuration arediscussed, which involved international collaboration among severalorganizations utilizing the latest concepts in electronic technology. Thetechnical details and functional per-formance of the digital electroniccontrol system are described relative to fulfilling the particularrequirements of a tandem rotor helicopter. Finally, operational andinstallation features of the engine control system, such as reliability,maintainability, diagnostics, history recording, health monitor-ing, aircraftincorporation and cost-of-ownership are summarized to ensure that the originaldesign philosophy and goals of the program would be satisfied.

A-9 ..

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DOC. NUIER: 18

TITLE: The Future Roles of Flight Monitors in Structural UsageVerification

AUTHOR: A.E. Thompson, Sikorsky Aircraft Division, United TechnologiesCorp.

PUBLISHER: American Helicopter Society - National Technical SpecialistsMeeting

DATE: October 1988

DOC. TYPE: Conference Paper

ABSTRACT: Structural substantiation of helicopter dynamic components forfatigue has traditionally combined three elements - component strength,aircraft flight loads, and an assumed usage spectrum. While componentstrength and flight loads are measured, most substantiating usage spectra arebased on general military or civil specifications, contractor experience, oruser and pilot surveys. All of these methods are filled with assumptions andcannot begin to address the mission profile variabilities. Since helicopterdynamic component replacement times can be very sensitive to the assumed usagespectrum, it is necessary to define a "realistic mission profile". Pastefforts in this direction have included detailed load/criteria studies,mission simulation flight tests, and pilot/user questionnaires. Thedevelopment of flight monitors will provide major opportunities to understandaircraft usage. This paper discusses past and current limited aircraftmonitoring programs at Sikorsky. It then describes future monitors underdevelopment which will provide fleet-wide continuous usage monitoring, andregime recognition algorithms which will provide rate of occurrence data forall critical flight conditions. It if: emphasized that monitor data must beused cautiously. The engineer must use quality data, based on statisticallysignificant survey programs. But most important, the traditional conservatismof the substantiation process must not be stripped away haphazardly. Thereliability of a substantiation depends upon a balance of realism in the usagespectrum and conservatism in the overall substantiation process.

DOC. NWZR: 19

TITLE: Health Monitoring of Helicopter Gearboxes

AUTHOR: D.G. Astridge, Westland Helicopters Ltd.

PUBLISHER: Aeronautic & Astronautic Assoc. of France - 8th Europ.Rotorcraft Forum

D A: August/September 1982

DOC. TYPE: Conference Paper

ABSTRACT: The various problems posed for gearbox health monitoring arediscussed, and the solutions applied to the Westland 30 helicopter aredescribed. These embrace the transition from traditional, well-knownlaboratory-based techniques and subjective evaluations, to the on-linefacilities of future aircraft such as the EH101 and growth versions ofWestland 30.

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DOC. NXMMR: 20

TZTLZ: The Health and Usage Monitoring of Helicopter Systems - TheNext Generation

ADTHOR: J.D. Roe, D.G. Astridge; Westland Helicopters Ltd.

PUBLISHER: Reprinted by AIAA

DATZ: Unknown

DOC. TYP : Conference Paper

BSTRACT: The paper discusses the relevance of health and usage monitoringsystems to the improvement of airworthiness and life cycle costs of helicop-ters, addressing the findings and recommendations of the HARP report/review ofhelicopter airworthiness (CAP.491, CAA, June 1984). The advanced on-boardmaintenance processor systems currently being designed for the Westland 30Series 300 and EH101 helicopters are described, covering sensors, interfaces,data links, processors and output devices. The functions include vibrationanalysis and quantitative debris monitoring systems for transmissions, powerassurance checking, low cycle fatigue and thermal creep monitoring for en-gines, and torque and strain monitoring for complete transmissions and rotorsystems. The systems include sensors and algorithms that have been developedvery recently and substantiated by rig tests to deliberate failure, by deve-lopment flying in arduous conditions, and by application to in-service air-craft. An overview of the development progranmes leading to certification ofthe on-board systems will also be given. The impact of these systems onmaintenance policies is also discussed.

DOC. NWZR: 21

TZLZ: Health and Usage Monitoring Techniques for Greater Safety inHelicopter Operations

AUTHOR: D.G. Astridge: Westland Helicopters Ltd., United Technologies

Corp.

PUBLISHR: international Journal of Aviation Safety

D&TZ: September 1985

DOC. TYPZ: Journal Paper

A8TRACT: The paper discusses work being done to monitor the integrity ofhelicopter transmissions during operation. Health monitoring should provideearly warning of surface wear modes, a clear rejection signal for surface wearmodes, and means of corroborating the indications at the aircraft bymaintenance personnel. For transmissions, the primary usage parameter istorque-transmitted, although in instances where rotor loads are transmittedthrough the gearbox casing, rotor loads and moments may need to be analyzed.Significant advances have been made in gearbox health monitoring technology,particularly in quantitative debris monitoring (i.e., the Tedeco QDM system),and in enhanced vibration signal averaging (i.e., Wetland's vibrationanalysis techniques have demonstrated the ability to detect cracks andfracture modes before they are visible to the eye).

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DOC. UM U: 22

TITLE: Helicopter Gear Box Condition Monitoring for Australian Navy

AUTHOR: K.F. Fraser, C.N. King; Aeronautical Research Laboratories

PUBLISHER: Reprinted by AIAA

DOC. TYPE: Conference Paper

ABSTRACT: The Aeronautical Research Laboratories has been involved for morethan a decade in studies on behalf of, and in the provision of scientificadvice to, the Royal Australian Navy on airworthiness matters in respect ofthe main rotor gear boxes for its Wessex Mk 31B and Sea King Mk 50helicopters. Work has been undertaken in the two major areas of gear boxhealth and fatigue life usage monitoring. The health monitoring program hasincluded both oil/wear debris analysis and vibration analysis. Significantadvances in the area of early failure detection have been achieved in thevibration work. Safe fatigue lives of all gears in the main rotor gear boxesfor Wessex and Sea King have been estimated for Australian operatingconditions. Prototype equipment developed at these Laboratories and currentlyfitted in some Sea King helicopters estimates fatigue life usage of gearsduring flight and is capable of monitoring actual life usage for individualgear boxes.

DOC. NU3UU: 23

TITLE: Helicopter Health and Safety

AUTHOR: G. Norris

PUBLISHER: Flight International

DATE: January 1990

DOC. TYPE: Magazine Article

ABSTRACT: The drive to improve the airworthiness of civil helicopters isbeing tackled on three fronts: design, technology, and operations. Newhelicopters are being developed which embody airliner standards of safety andsystem redundancy from the first set of designs. Microprocessor-basedtechnology, principally in the area of HUMS and FDR's, is being integratedinto existing helicopters. Operations are being made safer by revisedregulations.

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DOC. NW0BZR: 24

TITLE: 10th Helicopter Health Monitoring Advisory Group (HHMAG)Meeting Minutes

AUTHOR: S.L. James, Helicopter Health Monitoring Advisory Group

PULISEER: Helicopter Health Monitoring Advisory Group

DA Z: April 1989

DOC. TYPI: Meeting Minutes

ABSTRACT: The minutes include three briefings and two trial updates. Thebriefings are "AS332 Mk2 Health Monitoring" by M.R. Francois of Aerospatiale,"EH101 Health Monitoring" by Signor Bruno Maino of EHI, and "Review of RotorSystem Catastrophic Failures" by Mr. Andrew of MJA Dynamics. For the AS332trial, seventy vibration recordings and thirty-two oil debris samples weretaken. The first flight of the full HUMS on-board system was delayed. Forthe S61 trial, the two aircraft involved in the trial would be operational inlate June 1989 and the other in August 1989. Also, three thousand hours ofmonitoring will permit strip evidence to be correlated to SOAP analysis.

DOC. NWMR: 25TITLZ: 11th Helicopter Health Monitoring Advisory Group (HHMAG)

Meeting Minutes

AUTHOR: S.L. James; Helicopter Health Monitoring Advisory Group

PUBLZSUSH: Helicopter Health Monitoring Advisory Group

DMTE: October 1989

DOC. TYRZ: Meeting Minutes

ASST!MC: The minutes include four briefings and updates on the S61 trial andthe AS333 trial. The briefings are "Application of Expert Systems inImproving Helicopter Airworthiness" by the University of Exeter School ofEngineering (condensed report also included), "HUMS: FAA Update" by J.D.Swihart of FAA Southwest Region, "ROTABS: Rotor Trim And Balance System" by T.Staub, and "RADS" by K. Pipe of Stewart Hughes.

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DOC. NWUM: 26

TIT=: Helicopter Health Monitoring from Engine to Rotor

aT OR: J.F. Marriott, J.F.M. Kaye; Hawker Siddeley DynamicsEngineering Ltd.

PUBLISHmR: ASME - Gas Turbine and Aerospace Congress

DAT: June 1988

DOC. T!PZ: Conference Paper

ABSTRACT: Recent tragic accidents have focused attention on the dangers ofunmonitored helicopter dynamic assemblies. Methods are available to monitorthe entire power train from the engine to the rotor. Apart from the obvioussafety advantages, such systems offer the additional benefits of increasedavailability, a planned maintenance schedule, and a reduction in life cycleCosts.

Historically, monitoring systems have evolved from isolated processing units,each performing single functions. Hawker Siddeley Dynamics Engineering Ltd.,in conjunction with Stewart Hughes Ltd., is developing a modular andintegrated health and usage monitoring system. After a brief discussion ofhealth monitoring equipment evolution, this paper focuses on the practicalapplication of the techniques required to ensure the health of the modernhelicopter.

DCC. NWZR: 27

TITLU: Helicopter OperaOtors Forecast Steady Growth into Mid-1990.

A!BOR: N.C. Kern3tock

PUBLISM3R: Aviation Week & Space Technology

D= : February 1990

DCC. T: Magazine Article

ABSTPACT: The global civil helicopter industry has experienced a rebound,although business has not yet returned to the high levels seen in the late1970s. Four operators typify those who are achieving success by controllingthe growth of existing business and their entry into new markets, as well asexploiting profitable niches. While these companies' operations encompass awide variety of helicopter missions, three major markets are responsible formost of the growth: the oil industry, police and public service, and madicalflight service.

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DOC. N aMU : 28

TZ!L=: Hoverview - More HUM Trials Due

AUTEOR: Helicopter World

PUDLZSHER: Helicopter World

DA'Z: January-March 1990

DOC. TYPZ: Magazine Article

ABSTRACT: A series of trials, due to start in February 1990, on North Seahelicopters represents a continuation of the UK Civil Aviation Authority'sthrust to establish the utility and effectiveness of health and usagemonitoring (HUM) in service. British International Helicopters (BZH) willconduct the trials on two of its Sumburgh-based S61N helicopters. The trialsinvolve a total of 1,100 hours flying time over twelve to fifteen months. TheHUM equi.ent will analyze data from a range of sensors to detect faults intheir very early stages. Sensors include debris monitors, accelerometers, anda fixed optical tracker for accurate sensing of rotor track and lag. The on-board HUM processor can also derive high-level safety and maintenanceconclusions.

DC. NWMZR: 29

TlL.: The Integration of Health Monitoring Techniques for HelicopterGearboxes

anOa: Comu. M.J.D. Brougham; Royal NAvy MOD Directorate ofHelicopter Proj.P. Gadd; Naval Aircraft Materials Laboratory, RNAY Fleetlands

PUBLZaSf: The City University - llth European Rotorcraft Forum

D=Z: September 1985

DCC. !!3: Conference Paper

£35TflC!: This paper discusses the use of a combination of health monitoringtechniques to provide comprehensive coverage of possible failure modes in atypical transmission gearbox. From experience gained in research anddevelopment work sponsored by the UK Ministry of Defense in recent years, thepaper explores the relative value of conventional status parameters such asoil level, pressure and temperature, together with the newer techniques ofwear debris and vibration analysis.

The use of health monitoring techniques in a matrix to provide both earlywarning of failure and diagnostic information is considered, as well as theeffect of design features such as transmission configurations, oil filtrationstandards and filter bypass arrangements. The problems of data coll~ction andprocessing are also discussed.

The development of the Anglo Italian ZH 101 Health &id Usago Monitoring Systemis used to illustrate the process of sensor location, validation of processoralgorithms, and the planning to achieve full syst4A certifiCatiOn.

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DOC. NMMU: 30

TXTLZ: KRASH Analysis Correlation with the Bell ACAP Full-ScaleAircraft Crash Test

AV !OMR: J.D. Cronkhite, Bell Helicopter TextronL.T. Hazza; Aviation Applied Technology Directorate, U.S.AVSCOM

PMLSMIR: American Helicopter Society - National Technical Specialistseeting

DaTE: October 1988

DOC. MMS: Conference Paper

ARSTAC: The Bell ACAP aircraft, developed under the U.S. Army's AdvancedComposite Airframe Program, was designed to meet the Army's stringent crashsurvivability requirements using the 1(RASH analysis combined with testing ofcritical energy-absorbing structural components. The full-scale aircraft wascrash tested at the Impact Dynamics Facility of NASA Lanqley Research Centerand successfully demonstrated that it provided crash protection for theoccupants and fully met the ACAP crash requirements. The actual testcondition was somewhat more severe than planned. Also, the onboatdacceleration data was lost during the test and comparisons of the test resultswith the KRASH simulation had to be conducted using high speed photo motionanalyses and post test MasurAents. FOr coarison puZposes, the KRASHanalysis was updated after the test to represent the actual test condition and.to incorporate unexpected damage that hd occurred to a tail gear fitting andthe engine deck, but was not included in the origins}, analysis. Compaisonsof the KRASH analysis and test shoved good agreement and verified that KMHwas a viable analytical tool for the, desiga of composite airframe structuresfor crash impact.

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DOC. NWflU: 31

TITLE: Mastering a Complicated Beast

WTNOR: M. Hodges, Georgia Institute of Technology

PUBLISHER: Research Horizons

DATE: Spring 1990

DOC. RYPE: Magazine Article

AMSTRACT: At the Center of Excellence for Rotary-Wing Aircraft Technology(CERWAT) at the Georgia Institute of Technology, fourteen faculty and aboutthirty graduate researchers address basic research questions that U.S.industrial and government laboratories are not equipped to handle. Theresearch at CERWAT centers on four key areas: aerodynamics, aeroelasticity,structures and materials, and flight controls and mechanics. A key disciplinefor rotorcraft is understanding turbulant flow. From the point of view of therotor, one must understand the motion of vortices that spin off the blade, andfrom the point of view of aeroelasticity, one must understand the forcesexerted by the turbulent downflow on the airframe. The researchers at CERWATmake use of a laser Doppler wind tunnel in conjunction with advanced softwaremodels. The software models are spreading out into industrial use.

Another effort has been to model the reactions of the pilot. For thispurpose, two types of models are in use: the linear model or autopilot, andthe nonlinear "shooting" model. The nonlinear model will regress time if itcrashes, and "take another shot" at controlling the aircraft. Other effortsinvolve modelling composite materials (e.g. a blade that twists when itstretches) and advanced control systems involving feedback.

DOC. NUMBER: 32

TITLE: MDHC's Enhanced Diagnostics System, A Unique and ComprehensiveApproach to Structural Monitoring

AUTHOR: J. Harrington III, D. Chia, J. Neff; McDonnell DouglasHelicopter Company

PUBLZSMER: Reprinted by AIAA

DATE: Unknown

DOC. TYPE: Conferenco Paper

ABSTRACT: Currently in ths helicopter industry, structural component livesand inspection criteria are established by damage tolerance or safe lifemethods. An accurate determination of the loading spectrum of the component isrequired for both methodologies. Structure monitoring of aircraft through theuse of flight data recorder technology could substantially reduce theuncertainties in the load spectrum used in component life analysis. McDonnellDouglas Helicopter Company has developed a multi-functional flight datarecorder system for the Army's AH-64A Apache Helicopter. One of the primaryfunctions of the EDS is to obtain operational loads data. EDS structuralmonitoring is unique because it uses aircraft mission subsystems data as wellas strain gage data to monitor loads ad aivcraft usage. The purpose of thispaper is to describe the EDS struct.ural monitoring approach and to propose amethodology for using the EDS structural loads data in a comprehensivestructural integrity program.

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DOC. NURZ: 33

TZ!LE: The Modularity of the Health and Usage Monitoring System

IUTVO7t: P.D. Baker; Smiths Industries Aerospace & Defence Systems

PUBLZSUR: Aeronautic & Astronautic Assoc. of France - 13th Europ.Rotorcraft Forum

DATE: September 1987

DC. TYPE: Conference Paper

ABSTRACT: The Health and Usage Monitoring System has functional flexibilityor modularity by application, while the core of the system, the Health andUsage Monitor, is modular by design and function. It is possible by thesemeans to produce a system which is sufficiently versatile to meet the needs ofthe rotorcraft operator, the requirements of the rotorcraft and enginemanufacturers, and those of the certifying authorities. The purpose of thispaper is to outline the range of facilities and functions available at thistime for health and usage monitoring.

Data can be accepted by the system from any type of sensor. These data arevalidated before compression and storage, for subsequent examination, or forimmediate utilization in a variety of functions. The functions themselves cancover the power plant, airframe, transmission, and rotor. Experience in thedevelopment and application of the system has been gained to a qreter orlesser extent in a variety of fixed- and rotary-wing aircraft, in both civiland military applications; it is this which is the basis of the paper.

DeC. NMWZ: 34

TITLE: Osprey's VSLED: Rewriting the Maintenance Manual

AU!OR: E.W. Bassett

PU = SLf: Rotor 6 wing International

DAT: June 1988

DC. TTPE: Magazine Article

ASTRCT: The VSLED is the aircraft health-monitoring system underdevelopment for the V-22 Osprey. VSLED consists of an airborne unit and asensor network. The airborne unit is built around a MIL-STD-1750 processorand two co-processors. The sophisticated and extensive sensor network putsVSLED in touch with engine and airframe components.

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DOC. NMWUR: 35

TITLZE: The On-Condition Qualification of the Trailing Edge Area ofthe UH-1H Metal Main Rotor Blade

AUTHOR: B. Dickson, Bell Helicopter TextronR. Arden; Aviation Applied Technology Directorate, U.S. AVSCOM

PUBLISHUR: American Helicopter Society - National Specialists Meeting

DD- Z: October 1988

DOC. TYPE: Conference Paper

ABSTRACT: A program has been conducted by Bell Helicopter Textron, Inc.(BHTI), under contract to AVSCOM engineering, to establish an on-conditionreplacement status for the UH-1H metal main rotor blade considering fatiguecracking along the trailing edge. Two test specimens constructed fromservice-returned blades were ured to generate crack growth data. Innovativeapproaches used in the test included application of a multistep spectrum ofbeamwise, chordwise, and torsional loads derived from the UH-1H operationalspectrum to simulate a 2-hour flight. Application of test loads included thesuperposition of the significant 1/rev and 7/rev chordwise loads torealistically account for the dynamic response of the blade in flight. Thepaper presents details of the derivation of the crack growth test loadspectrum, details of the test, and crack growth data generated that weresubsequently used to establish a safe inspection interval.

DOC. NWU: 36

TZTLE: Qualification and Fleet Introduction of the AH-IT Flight Loadsand Usage Monitor

AUTHOR: C.G. Schaefer, Jr.; Helicopter Loads and Dynamics, Naval AirComumond

PUBLISHER: Reprinted by AIAA

DOC. T!P3: Conference Paper

ABSTRAC: The U.S. Navy is currently assessing the validity of its presentfatigue methodology for rotary wing aircraft. NAVAIR is now involved in afleet usage survey that will attempt to collect a sizable database to evaluatethe current attack helicopter usage spectrum. The survey includes the designand installation of an instrumentation system that monitors flightenvironmental loads and operational mission usage of eight fleet Marine AH-iT(TOW) attack helicopters. This paper addresses that flight test efforto someof the problems encountered, and the introduction of the system into thefleet.

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- -- ; 17 ! : 'p 1' ' 'i i

DOC. NUMMIR: 37TITLZ: Qualification Testing of AH64 Fly-By-Wire Backup Control

System (BUCS)

AUTHOR: S.S. Osder, McDonnell Douglas Helicopter Company

PUBLISEMR: Reprinted by AIAA

DITZ: Unknown

DOC. TYVE: Conference Paper

ABSTRACT: The AH64 helicopter's fly-by-wire backup control system wasqualified using a combination of tests performed on the aircraft and in aclosed loop validation facility. The backup fly-by-wire system concept isdescribed and the test procedures used to qualify that system are reviewed.Some key technical issues relating to the control logic used to monitor systemhealth and to detect the conditions requiring automatic backup controlengagement are discussed.

DOC. NOIZR: 38

TITLU: Rotorcraft Trends - Part 2 Requirements and Monitoring

AUTHOR: T. Ford

PUBLISBZR: Aircraft Engineering

D=TZ: December 1985

DOC. TYPf: Magazine Article

ABSTRACT: A CAA working group on helicopter health monitoring concluded thatfor future helicopter designs, the transmissions and rotor systems wouldbenefit most from the use of health monitoring techniques. Three other areaswere also identified as imoortant areas for effective monitoring: flightcontrol systems, structure, and engines and fuel systems. Requirements andmonitoring reco=endations are made for eaCh of these five areas.

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DC. NUI P: 39

TITLE: Sikorsky Adopts Cautious Approach to Japanese Civil HelicopterMarket

AUTHOR: Unknown

PUBLISHER: Aviation Week i Space Technology

DATE: February 1990

DOC. TYPE: Magazine Article

ABSTRACT: Although the Japanese have identified a need for about 3,300heliports and 600 helicopters over the next 20-30 years to ease the transpor-tation network gridlock, 3 main hindrances have prompted Sikorsky Aircraft toexercise caution in pursuing the Japanese civil helicopter market. First,Japan has complex and rigid helicopter certification and flight regulations.Second, the national government recently implemented tax codes that will soonmake helicopter ownership less attractive. The third and most importantreason is that Japan has been experiencing, and for the foreseeable futurewill continue to experience, a chronic shortage of trained helicopter pilots.

DOC. NUMBER: 40

TITLE: Simulator Evaluation of Instructional and Design Features forTraining Helicopter Shipboard Landing

AUTHOR: D.J. Sheppard, S.A. Jones, D.P. Westra; Essex CorporationJ.J. Madden; Naval Training Systems Center

PUBLISHER: Human Factors Society - Proceedings of 32nd Annual Meeting

DATE: 1988

DOC. TYPE: Conference Paper

ABSTRACT: The effects of four instructional issues and one simulator designfeature for training helicopter shipboard landing on small ships were testedin the vertical takeoff and landing (VTOL) simulator at the visual technologyresearch simulator (VTRS), Naval Training Systems Center. They were: (1)field of view (VTRS versus a test field of view), (2) task chaining (segmentedbackward chaining versus whole task training), (3) augmented cueing (augmentedcueing versus no augmented cueing), (4) length of training (18, 27, and 36trials), and (5) the timing of seastate introduction (early versus late). Theexperiment utilized an in-simulator transfer-of-training paradigm in whichpilots who were not proficient in the helicopter shipboard landing task weretrained under one of several experimental conditions, then tested on thetransfer condition (that represented maximum realism) in the simulator.Thirty-two pilots each completed a total of 54 trials (36 training, 18 trins-fer). Pilots were tested in the transfer condition (six trials) after their18th, 27th, and 36th training trial. Of the experimental instructionalissues, task chaining had the largest effect, with better performance in allsegments of the task for pilots who were trained with the backward-chainingsequence than for pilots who received whole task training. Augmented cueingdid not yield the transfer performance anticipated. Seastate introduction hadno effect on performance. Field of view had some marginal effects on verticalperformance in the hover, with better performance for pilots who were trainedwith the combination VTRS field-of-view and backward-chaining. Results sug-gest a diminished rate of learning after 33 simulator trials (includes 27training trials and six transfer trials of the first probe).

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DOC. UMU : 41

TITWL: Strengthening the Weak Link of Fatigue Qualification

AUTHOR: K.M. Rotenberger, U.S. Army Aviation Systems Comnand

PUBLISHER: Unknown

D=I!: Unknown

DOC. TYPE: Conference Paper

ABSTRCT: The "weak link" in the fatigue substantiation process is theaircraft usage spectrum. In recognition of this, the Army is conductingseveral programs designed to better account for the actual usage of Armyhelicopters. A pilot survey program was conducted for the AH-1 and UH-1systems and produced updated spectra that incorporated new missions andtactics previously unaddressed. Many programs involving flight data recordersare currently underway. They are designed to record the data necessary tocontinuously define the condition of an aircraft in flight. Onceincorporated, this will allow the Army to monitor and update usage spectra asnecessary and thereby enhanco the "weak link" of the fatigue substantiationprocess.

DOC. NMZR: 42TITLE: UH-60 Flight Data Replay and Refly System State Estimator

Analysis

AUTHOR: M. Whorton, University of Alabama

PUBLISHmR: AIAA - 28th Aerospace Sciences Meeting

DATZ: January 1990

DOC. TYPE: Conference Paper

ABSTRACT: Research currently underway at The University of Alabama FlightDynamics Lab investigates concepts for implementation of a ground-based UR-60flight data replay and refly system. A variation of a linearized extendedKalman filter is implemented which utilizes a mathematical model of the UH-60to accurately re-create a UH-60 helicopter flight based on flightmeasurements. Essential in this paper is the development of the UN-60mathematical model, an experimental verification of the Kalman filterimplementation, and an experimental evaluation of filter sensitivity toinitial condition errors, measurement sample rate reductions, and modelparameter variations. Results indicate that vehicle dynamics are representedwith sufficient fidelity by the UK-A mathematical model for both filter designand piloted simulation, providing a replay and a refly capability.Experimental analysis of the Kalman filter indicates that the current filterexhibits a robust tracking ability for low measurement sample rates;demonstrates relatively fast, stable convergence in the presence of initialcondition errors; yet manifests a notable performance degradation due toweight variations.

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DOC. NICUZR: 43

TITLE: U.S. Army Flight Condition Monitoring.

AUTHOR: R.L. Buckner, D.J. Merkley; Applied Technology Laboratory,U.S. Army Research and Technology Laboratories (AVSCOM)

PUBLISHER: Unknown

DATE: Unknown

DOC. TYPE: Conference Paper

ABSTRACT: The flight condition monitoring (FCM) method of acquiringoperational usage data is presented as it was developed from U.S. Armyhelicopter service usage programs from 1964 to present. The importance ofincorporating operational usage data in fatigue design apprcaches, such assafe-life and damage tolerance, is discussed with emphasis on theestablishment of dynamic component fatigue lives. The Army's service usageprograms are critically reviewed to determine areas of sensitivity inestablishing design mission spectra for rotary-wing aircraft. The feasibilityof utilizing FCM with state-of-the-art microprocessor recorder technology onfuture in-service programs is presented with sugge,;ted unified approaches tomission spectrum development on current and future helicopter systems.

DOC. NUND3ER: 44

TITLE: Vibration Analysis for Detection of Bearing and Gear FaultsWithin Gearboxes: An Innovative Signal Processing Approach

AUTHOR: R.C. Kemerait, G.W. Pound, L.J. Owiesny; ENSCO, Inc.

PUBLISNER: Unknown

DATE: Unknown

DOC. T!PZ: Conference Paper

ABSTRACT: The principal purpose of thi3 research was to investigate thepossibility of enhancing the early detection of gear and bearing problems inhelicopter gearboxes utilizing more s6phisticited signal processingtechniques. Additional considerations were the applicability of theseimprovements to routine helicopter maintenance and use as an aid for in-flightreadiness. The selected research dealt with the processing of accelerationdata collected from the Navy TH-IL helicopter test bed. The aircraft wasstrapped down with the main rot ..: removed for safety reasons and the tailrotor left on to load tAre 42 degrees geirbox being investigated. The signalprocessing research dealt principally with the potential improvements to begained by utilizing thc complex and cosine squared cepstrum techniques.Considerable apparent 'ains in performance were achieved by a combination ofthe traditional and u-iique employments of theie cepstral techniques. Manyother signal processiag features were investigated and reported as by-productsof this research.

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A.2 OTZXR AZRCRUT DZAGEOSTICS

DOC. XZ[RE]: 45

TITLe: Allison Gas Turbine: in the Forefront of Vertical FlightPropulsion R&D

AUTHOR: L. Scipioni, Jr.; Allison Gas Turbine Division, General Motors

PUBLISHER: Vertiflite

DATE: May/June 1988

DOC. TYPE: Magazine Article

ABSTRACT: Allison Gas Turbine Division of General Motors is the majorproducer of light helicopter turboshaft engines. In the 1980s, severalturbine engine development programs were started to address 1990srequirements. The T800, a 1200-SHP engine, is a new, small engine for theArmy's Light Helicopter Experimental Program (LHX). The V-22 Osprey Tiltrotoruses the Allison T406 engine, a large turbine engine in the 6000-SHP category.The future thrust is towards lower cost and smaller, more reliable andpowerful turbines. Research and development areas include: investigation ofunique cycles, doubled power to weight ratio, greater than 25% reduction inSFC, increased reliability/maintainability, better affordability, improvedoperational capability, etc. The technologies needed to support thesedevelopment areas include improved high temperature materials, smallercomponents, and maintainability design characteristics.

DOC. NMUR: 46

TITLE: An Analysis of Air Force Management of Turbine EngineMonitoring Systems (TEMS)

AUTHOR: Capt. E.B. Hubbard III, Capt. G.A. Swecker; Air ForceInstitute of Technology, Wright Patterson AFB

PUBLISHER: Air Force institute of Technology, Wright Patterson AFB

DATE: June 1980

DOC. TYPE: Master's Thesis Report

ABSTRACT: Turbine engine monitoring systems (TEMS) are engine healthmonitoring and diagnostics tools being developed and tested for use on AirForce engines in order to improve and reduce the cost of engine maintenanceand management and to aid in the implementation of on-condition maintenance.Previous researchers have described the major features of TEMS, analyzed theresults of development and test efforts, and identified problems which must beovercome. This study examines the problem of fragmentation which exists inthe Air Force management of TEMS development and testing. The authorsdescribe and analyze the overall Air Force management of TEMS. Managementproblems were identified and classified into three major areas: structure androle problems, information flow and integration problems, and leadership andcommand problems. Four alternative management concepts were analyzed. Basedon this analysis, the authors recommend that the management structure bemodified, and a TEMS task force be established to more effectively utilizeTEMS for Air Force engine maintenance and management.

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DOC. NMWIR: 47

TTILZ: An Automated Between-Flight Visual Inspection ConditionMonitoring Syotem

UTHOR: P.T. Coleman, E. Nemeth, J.M. Maram, A.M. Norman; RockwellInternational, Rocketdyne Division

PUBLISHR: AIAA - AIAA/ASME/SAE/ASEE 25th Joint Propulsion Conference

DATE: July 1989

DOC. TYPE: Conference Paper

AESTRACT: This paper discusses the automation of between-flight visualinspections for reusable rocket engine system maintenance. A review ofcurrent turnaround maintenance procedures and the application of automatedinspection methods is discussed. In addition, the application of visionprocessing to images acquired by current methods of visual inspection isexamined.

DOC. NMER: 48

TITLZ: Design of Digital Self-Selecting ultivariable Controllers forJet Engines

AUTHOR: A.H. Jones, B. Porter, A. Chrysanthou; Centre for

Instrumentation and Automation, University of Salford

PMULZSUXR: AIAA - AIAA/SAE/ASME/ASEE 26th Joint Propulsion Conference

DATZ: July 1990

DOC. TYPl: Conference Paper

A8UTPACT: in this paper, the tunable digital set-point tracking PIcontrollers for linear multivariable plants developed at Salford are extendedto deal with plants with more output variables than input variables. Thisextension is effected by delineating the concept of asymptotic positive-realclosed-loop transfer function and by using this ccncept in the design of self-selecting highest- or lowest-wins controllers. The effectiveness of theresulting design methodology is illustrated by designing a self-selectinglowest-wins set-point tracking PI controller for a two-input five-outputturbofan jet engine.

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DOC. HMOZR: 49

TZXLZ: Diagnostics in the Extendable Integrated Support Environment(EZISE)

AUTHOR: J.R. Brink, Ph.D.; Battelle Columbus DivisionP. Storey; Sacramento Air Logistics Center, MMESD

PUBLISM: NASA Lyndon B. Johnson Space Center - SOAR '88 Workshop

D A!: November 1988

DOC. TYPZ: Conference Paper

ABSTRACT: EISE is an Air Force developed real-time computer networkconsisting of commercially available hardware and software components tosupport systems level integration, modifications, and enhancements to weaponssystems. The EISE approach offers substantial potential savings byeliminating unique support environments in favor of sharing common modules forthe support of operational weapon systems.

An expert system is being developed that will help support diagnosing faultsin this network. This is a multi-level, multi-expert diagnostic system whichuses experiential knowledge relating symptoms to faults and also reasons fromstructural and functional models of the underlying physical model whenexperiential reasoning is inadequate. The individual expert systems areorchestrated by a supervisory reasoning controller, a meta-level reasonerwhich plans the sequence of reasoning steps to solve the given specificproblem. The overall system, termed the diagnostic executive, accessessystems level performance checks and error reports, and issues remote testprocedures to formulate and confirm fault hypotheses.

DC. NwMzR: 50

TZ!LZ: Digital Data System Expected to Benefit Defense and Industry

AUTHOR: S.D. Nordwall

PULZSRER: Aviation Week & Space Technology

DAT3: February 1990

DOC. TVPZ: Magazine Article

ABSTRACT: The computer-aided acquisition and logistic support (CALS) programis a Pentagon program to shift technical weapon systems data from paper todigital storage. The first phase of the program ran from 1985 to 1989, andemphasized coordination with industry, infrastructure plans and initialstandards. The second phase is scheduled from 1990 to 1995, during which aCALS test network will be established. The third phase, from 1995 to 2000,will have CALS shifting to wide-scale industrial networks. The services havedesignated lead weapon systems to use CALS: the LHX helicopter and the AbramsMI tank from the Army, the A-12 advanced tactical aircraft, the V-22 Ospreyand the SSN-21 Seawolf submarine from the Navy, and the Advanced TacticalFighter from the Air Force.

The success of CALS depends on the creation 'of standards and technology.Creating a standard defense/industry interface poses an imediate problem.Another issue is how far to retrofit CALS, since 50-80% of existing weaponsystems will still be around in 2000.

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DOC. NOMBZR: 51

TITLE: Engine Monitoring

iAlTOR: S. Royek, R. Casagrande, P. Emile, D. Garcia, G. Gozemba;Ametek Aerospace Products

PUBLISNER: Avionics

DTZ: January 1990

DOC. TIPE: Magazine Article

ABSTRACT: The most sophisticated engine monitoring systems are on severalmilitary aircraft. Engine data is collected and analyzed, alerting the pilotto abnormal conditions. Also, vibration analysis combined with speed,temperature, pressure, engine cycles, life usage, and time/date stampingcreate maintenance schedules foz each engine. In a U.S. Navy study of anearlier engine monitoring system, maintenance per flight hour and prematureengine removals were reduced and actual flight hours were increased.

DOC. NfMMR: 52

TITLE: Evaluation of a Fault Tolerant Digital Engine Controller

AUTROR: W.E. Wright, J.C. Hall; Advanced Technology Control Systems,GE. Dr. J.J. Deyst, Dr. R.E. Harper; Charles Stark DraperLaboratory

PUBLISM: AIAA - AIAA/ASME/SAE/ASEE 25th Joint Propulsion Conference

DATZ: July 1989

DOC. 10P9: Conference Paper

ABSTRACT: In order to address aircraft engine control reliability andredundancy issues associated with advanced aircraft, the Air Force initiatedtwo programs known as INTERFACE I and I - L. The acronym INTERFACE is de-rived from Integrated reliable fault-tolerant control for engines. The Ad-vanced Technology Controls organization of General Electric Aircraft Enginesparticipated as a prime contractor in both INTERFACE programs. INTERFACE Iincorporated a military standard 1750A 16-bit processor architecture pro-grammed in Jovial, and INTERFACE II - L utilizes military standard 1815 Ada incombination with a 32-bit processor. Both programs produced triple redundantengine controls and feature a tightly synchronized, Byzantine resilient fault-tolerant computer architecture developed by the Charles Stark Draper Labora-tory. This paper presents an evaluation of the INTERFACE I engine control, aswell as preliminary evaluation of the INTERFACE I control. The results ofinvestigations into fault-tolerant parallel processing for engine controlswill also be presented.

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DOC. NMUM: 53

TZ!LZ: Full Authority Digital Electronic Engine Control SystemProvides Needed Reliability

AUT.OR: D.A. Fiebig; Controls Engineering, Government Engine Business,Pratt and Whitney

PUBLISHER: AIAA - AIAA/SAE/ASME/ASEE 26th Joint Propulsion Conference

DMT3: July 1990

DOC. TYPE: Conference Paper

ABSTRACT: During the past decade the reliability of control systems for Pratt& Whitney military engines has improved by a factor of six. An operationalengine of current configuration now requires the removal of a control systemcomponent for maintenance action less than once a year. This significant im-provement is the result of a concentrated effort to address the elements ofproduct quality and reliability at all stages of development including design,development, manufacture, and deployment. In addition to basic designimprovements which rely on digital electronic control modes, specific design,development test and production quality improvement initiatives have contri-buted to the overall reliability enhancement. Such programs as environmentalstress screening, combined environment reliability testing, durability test-ing, production readiness programs, field service evaluations, and manufac-turing process reviews made significant improvements in product reliability.Throughout the next decade, significant improvements in reliability will con-tinue to be made because of the incorporation of further digital electroniccontrol enhancements (dual channel full authority digital electronic controlsystems) aad the application of propulsion and power system integrity program,concurrent engineering, and total quality management initiatives for thedesign, development, and production programs.

DOC. NWZR: 54

TZTLE: Integrated Avionics

UTHOR: R.E. Friday; King Radio Division, Allied Signal CorporationM.A. Card; Bendix Avionics Division, Allied Signal Corporation

PULZSB: Aerospace Engineering

DiA2: April 1988

DOC. TYPE: Magazine Article

ANTRACT: The trend in avionics systems for general aviation is towards theintegration of sophisticated navigation, display and flight control syst. ts.One major hinderance to full integration has been the ranging degree ofincompatibility between components that typically comprise an avionics sysRecently introduced general systems include electronic flight instrumentsystems, long-range navigation systems and digital flight control systems.New display systems, data transfer methods, and cockpit management tools arebeing developed to deal with the increased amount of data available to theflight crew. Among the technologies being investigated are flat paneldisplays, fly-by-wire control systems, voice command and control, high-speedbi-directional data buses, and fault tolerant data management computers.

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DC. ~N : 55

TITh3: Power Analyzer and Recorder (PAR)

XUTZOR: Teledyne Avionics

PDISM: Teledyne Avionics

D=: Unknown

DOC. TYPl: Product Brochure

ABSTRACT: PAR is Teledyne Avionics' power analyzer and recorder. It is aturbine engine health monitor designed to analyze and record aircraftoperation and display information to the pilot. PAR continuously monitors Ni,N2, Np/Nr, EGT, and Torque, and generates all Atmospherics - PALT, DALT, OAT.Data can be downloaded to a printer or PC via a RS232 coznunications port.

DOC. NMMU: 56

TZTIL: Reconfigurable Integrated System Architecture for FutureMonitoring Systems

AUTOR: W.A. Clearwaters; Helitune Ltd.

PUBLISOR: DLR, Institut fur Flugfuhrung - Proceedings of 15th AIMSSymposium

D A: September 1989

DOC. TOl: SyMposium Paper

ABSTRACT: Next generation monitoring systems will require capabilities notfound in current systems. In order to meet the challenges posed by thesesystems, Helitune has instituted the ARIA (Advanced Reconfigurable IntegratedArchitecture) program to capitalize on recent advances in computer technology,particularly in the areas of object oriented programaing systems, VLSI, anddatabase systems. ARIA proposes to employ the poavr inherent in the objectparadigm to address the problem of integration and reconfiguration in futuremonitoring system. ARIA also encompasses a hardware elecwnt to develop amodular, distributed hardv*re set and a software toolbox for the reliableimplementation and maintenance of these new systems.

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DOC. NMMM: 57

TZTLU: A Self Diagnostic System for Piezoelectric Sensors

UThSOR: W.J. Atherton, Ph.D., P.M. Flanagan, Ph.D.; Cleveland StateUniversity

PUBLISHZR: AIAA - AIA&/ASME/SAE/ASEE 25th Joint Propulsion Conference

DTE: July 1989

DOC. TIDE: Conference Paper

ARSTRACT: A technique for determining the mounting conditions of apiezoelectric accelerometer is presented. This technique electricallystimulates the piezoelectric element in the "diagnostic" frequency bandmeasuring the electrical frequency response characteristics across acapacitive load impedance. The diagnostic frequency band is typically muchhigher than the operating bandwidth of the accelerometer. The resonantfrequencies of the accelerometer are included in the diagnostic band. Bymonitoring the shift in these resonant frequencies via electrical stimulatiqntechniques, certain diagnostic conditions including mounting conditions can bedetermined. Experimental data from a compression mode accelerometer is used:to demonsrate this technique.

DwC. Nun : 58

21"4U: Systems Approach to Engine Moitoring

AUflf: G. Harris: Data Trend "

PMU : Avionic3

UI: February 1986

DOC. flfl: agazine A-rticle+

AESTRACT: The JOIT (Jet Electronics *ad Technology) ET$-00 is an infliqhtengine monitoring system that provides oporAtinq p~rafter triend anal ysisgraphs by ianns cf a riemoable zodule that storoes the data. -.The 'easult- issubstantiallXy improved maintaiaab "ltty and $.stuat c~ilibratioa.0

DoC. HMU : 59:

tITLt: -?re4 Analysis and Diagnostic Codes fortrai&±a4 2?arpose

MTO:G. Torefla: ltaliayi Air F1orce Acadsmy

P tZAZfAI± MM ArM/,e/A~tLt/SEE26t l foint Proplaion Conferce

D&2It: July 1990 .t.. .,

DOC, tV5; Conference Papsr . ..

aaSI&ifc the im-portance and ntc6ssity of M641ation'duritg tb* training ofpevtonnel1 as yoeU41 as duria;g oa-tcndittion iintenat6 activ-tiqh; arediocussed. Numerical codes hav e be" develqpe for ti3s aim. atd the resultsfor trend anatpis $Wd tOt diaOSt callat s azep"dnt. The-paperdealt With di.f.Sr t (uIt sitUi4" and vith 'te4a9i wi dit nr"ntco iquatio .,",3.

?rA30 " -'

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A.3 ROCKET EGInE DIAMOSTZCS

DOC. ICWBER: 60

TITLE: Artificial Intelligence Techniques for Ground Test Monitoringof Rocket Engines

AUTHOR: M. Ali, U.K. Gupta; Center for Advanced Space Propulsion,University of Tennessee Space Institute

PUBLISHER: AIAA

DATE: July 1990

DOC. TiPE: Conference Paper

ABSTRACT: The goal of the ongoing research described in this paper is todevelop an expert system which can detect anomalies in Space Shuttle MainEngine (SSME) sensor data significantly earlier than the redline algorithmcurrently in use. In the training of such an expect system, we have focusedon two approaches which are based on low frequency and high frequency analysesof sensor data. Both approaches are being tested on data from SSME tests andtheir results compared with the fIndings of NASA and Rocketdyne experts. Ourprototype implementations have detected the presence of 4nomalies earlier thanthe redline algorithms that are in use currently. It therefore appears thatour approaches have the potential of detecting anomalies early enough to shutdown the engine or take other corrective action before severe damage to theengine occurs.

DOC. NMBER: 61

TITLE: Comparison of Nonlinear Smootheas and Nonlinear Estimators forRocket Engine Health Monitoring

AUTHOR: B.K. Walker, E.T. Baumgar'.ner; Health Monitoring TechnologyCenter for Space Propulsion Systems, University of Cincinnati

PUBLI3HER: AIAA

DATE: July 1990

DOC. TYPE: Conference Paper

ABSTRACT: T. new nonlinear, real time smoothing algorithm is applied to theproblem of tijtimating some of the parameters that describe the dynamics of areusable space propulsion system, in particular parameters that are likely tochange when engine degradations occur. The results are compared ta those froma nonlinear filtering algorithm based upon the extended Kalman filter. TheSSME operating at its 100 percent rated power level is used a3 the baselinepropulsion system with the filter and smoother designs based upon a reducedorder dynamic model of the SSME. The data used to drive the algorithms isgenerated by a high fidelity transient simulation of the SSME with smal!magnitude random dither signals applied to the fuel side control valves andwith substantial random noise added to the measured outputs. The resultsindicate the smoother providet, substantial j.provement over the filter interms of parameter estimation accuracy. However, both algorithm3 are notalways able to track the correct parameter Values when changes in these valuesrepresenting engine degradations are introduced in the simulation thatproduces the data. The papet concludea with an examination of the effact ofmeasurement biases on the parameter estimation performance of the smoother anda method to compensate these effects.

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DXC. XWIU: 62

TITLE: Condition Monitoring of Liquzid Rocket Engines UsingStatistical Process Control

IMCP: E. Royer, D. Wolting; Aerojet TechSystems Company

PUBLIBUR: AIAA

DATZ: July 1989

DOC. TYPZ: Conference Paper and Slides

ABSTRACT: This paper discusses the application Of statistical process controlmethodology to problems of engine performance and condition monitoring. Thesemethods include simple X-bar, R, and Cumulative sum control charts. A casestudy is presented, where these techniques are applied to evaluate theperformance of liquid rocket engines over time. The results show that thesemethods can be very effective aids in analyzing flight data and in confidentlydeveloping performance predictions for future Missions.

A multivariate control chart is also presented for Auwrarizing the-cond4tionof liquid rocket engines. The method comb~ines numerous MelUrezent.s into asingle statiatic which characteriZ0s overall engine'stats., -Tests of,3ignificaice based on this statistic are 3.hownmto identify faults or anomalies,which wo)uld otherwise go undetected. Diagn~oatic procedures 'UsiAg multiv'ariate*mthoda axe discussed, as are ways to reduce both Type l and:Type ZZ erroXs ill'engine condition monitoring applications.

WCC. XWOUE: 63

TZTLE: Cost-Benefit Modeling ;or Roc]ket-:Engine Coudto MonitoringSystem

AWTSMP. C.J. Mi3i; Rccketdyne Division, RAockwell international

WIUSSHI: AIAZI,

DAM uly 1989

DCC.. TYPI: Conference Paper

AMTWCT"!Condition monitoring 3ystenv (CkS) for rocket enqtnes maycOnitribute signifioantly to future d6aoreiassd launch oosts, dU'* to inpovemerits14 Oz.- overall reliability of propulS.o system and strealmlined pro-launchand rt~urbishment processes. This papex disovases a mathodology for assessiag.tht cdst3 and benefits of rocket ezns CM,4S for future launzh vehicles. Themethodology is based on net life cyale cost: s4avinqs for tha total vehicle and

Paylod 3ysam. t co~nsiders the actual co*it of CmS, tthe unreliabilityp~nat esof the CMS, and it3 benef-Ioial' itfects ou'reducing operational oOsts

.-ahc, tiCre4s1ng overall engine reliai.i.y~.'.

.7'fPh.ris of the work reported in this e s*negn reliability_i-iprov0ements and decreased costs f or a l~uuch ey :-le. -The rei-bility m~odelknqv~a perf ormed Using a simulation method. i\asetj ov fault 'treeim ior two icey~r, 0Ponent.(;rOupse ite., turrbopuzM and .nsin cobustion u&hW.;a with nozzle.Changea.itl launch cycle costs were et nduif HarkoyChain akpproach

iwhich accounts for the cost of engine-daused 1?4nqlhf vehiAX, iailures. The.* Vethodoloqies are described, prelimiliary pa..JmetV~i., =est.ItA tpESented for',.usable angines, and cott drivers dIcUU336.i

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DOC. NEB3ZR: 64

TITLE: Cost Effectiveness Perspectives for Launch Vehicle HealthMonitoring Systems

AUTHOR: R.L. Puening; Martin Marietta Astronautics Group

PUBLISHER: AIAA

D TE: July 1990

DOC. TYPZ: Conference Paper

ABSTRACT: This paper describes methodologies to quantitatively determine thecost effectiveness of health monitoring systema for different types of launchvehicles and launch vehicle stages. The interaction of health monitoring withother programmatic element cost saving measures is described. Individualelements of cost saving benefits and penalties of health monitoring systems asapplied to launch vehicles are assessed utilizing a health monitoring costmodel spreadsheet tool developed by the author.

DOC. NUMER: 65

TITLE: Development of a Health Monitoring Algorithm

AUTHOR: E. Nemeth, A.M. Norman Jr.; Rocketdyne Division, RockwellInternational

PUBLISHER: AIAA

DATE: July 1990

DOC. TIYPE: Conference Paper

ASTRACT: An algorithm has been developed using fourteen measurements of the$SME rocket engine that in many cases provides significantly betterperformance (detection of damage and then shutdown) than existing redline-typealgorithms.

Easontially, the-algorithm has permissible zones for functions of combinationsof the variables, rather than just limits on the values consideredindependently. The limit -functions are developed ad hoc rather than usingsome estimation-control oriented technique.

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DOC. NWMZR: 66

TZTLI: Diagnostic Needs of the Space Shuttle Main Engine

AUTHOR: RR. Teeter, A.E. Tischer, R.C. Glover, B.A. Kelley; BattelleColumbus Laboratories

PUBLISHER: Battelle Columbus Laboratories

DATE: 1984

DOC. TYPE: Technical Paper

ABSTRACT: A study is being conducted for NASA on potential diagnostic systemimprovements to the SSME. This paper reports midterm progress including: (1)the results of a failure mode review identifying key diagnostic needs; (2) theresults of a survey of diagnostic tecnniques that might be applied to theSSME; and (3) application to the SSME of a Battelle developed tool (thefailure information propagation model) for analysis of diagnostic needs. Itis concluded that opportunities for significantly improved diagnostics existin a number of areas. Future plans are described that are directed towarddevelopment of a diagnostics strategy and design recomtendations for animproved diagnostic system for the SSME.

DOC. NMBZR: 67

TITLE: An Expert System for Fault Diagnosis in a Space Shuttle MainEngine

AUTROR. M. Ali, U. Gupta; University of Tennesse Space Institute

PUBLISHER: AIAA

DATE: July 1990

DOC. TTPZ: Conference Paper

ABSTRACT: The detection and diagnosis of SSME faults in an early stage isimportant in order to allow enough time for fault preventive or correctivemeasures. Since most of the faults in a complex system like SSME developrapidly, early detection and diagnosis of faults is critical for the survivalof space vehicles. We have designed an expert system for automatic learning,detection, identification, verification, and correction of anomalouspropulsion system operations. This paper describes an innovative machinelearning approach which is employed for the automatic tracking of this expertsystem.

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DOC. NUMMZR: 68

TITLE: Health Monitoring System for the SSNE: Fault DetectionAlgorithms

AUTHOR: S. Tulpule, W.S. Galinaitis; United Technologies ResearchCenter

PUBLISHR: AIAA

DATZE: July 1990

DOC. TYPE: Conference Paper

ABSTRACT: A health monitoring system (HMS) framework for the SSME has beendeveloped by United Technologies Corporation for the NASA Lewis ResearchCenter. As part of this effort, fault detection algorithms have beendeveloped to detect the SSME faults with sufficient time to shut down theengine. These algorithms have been designed to provide monitoring coverageduring the startup, mainstage and shutdown phases of the SSME operation. Thealgorithms have the capability to detect multiple SSME faults, and are basedon time series, regression and clustering techniques. This paper presents adiscussion of candidate algorithms suitable for fault detection, followed by adescription of the algorithms selected for implementation in the HMS and theresults of testing these algorithms with the SSME test stand data.

DOC. NUMBER: 69

TITLE: Health Monitoring System for the SSME: Hardware ArchitectureStudy

AUTHOR: J.K. Kamenetz: Hamilton Standard Division of UnitedTechnologiesM.W. Hawman, S. Tulpule; United Technologies Research Center

PUBLISUZR: AIAA

DATE: July 1990

DOC. TYPE: Conference Paper

A-STRACT: This paper presents a hardware architecture for a SSME HMS. Thearchitecture study was conducted in conjunction with a NASA sponsored programto develop a framework for SSME HMS for ground test and, potentially, flightapplications. The function of the ground based HMS was two fold: protectengines during ground test and provide a test bed for HMS development. Theflight system would potentially serve as a maintenance aid and as a safetyfeature. The requirements of the program were to use as much of the existingcontroller and facility instrumentation as possible and to utilize existing ornear term technologies. The HMS was intended to be designed, developed, andqualified for ground use within 5 years. Fundamentally, the HMS design shouldnot preclude flight-based operation.

The paper follows a defined conceptual design process. The requirements forboth systems are both stated and analyzed. A multi-processor, distributed,VME system is envisioned for the ground test hardware. By repackaging theboards, the same concept is shown to be usable for the flight system. Thepaper concludes with an analysis of weight, power, and reliability withrespect to variations in functionality.

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DOC. NMWI: 70

TITLE: HERMES Propulsion Subsystem On-Board Diagnostic Monitoring andControl

AUTHOR: N. Cornu, G. Gerbes; Societe Europeenne de Propulsion, Spaceand Defence Group

PUBLISHER: AIAA

DATE: July 1990

DOC. TYPE: Conference Paper

ABSTRACT: After a description of the HERMES propulsion requirement, physicalcharacteristics and basic principles selected for the spacionics, this paperis intended, in a second part,. to set up the objectives of the on boarddiagnostic monitoring and control, the monitoring concept and the monitoringmethod to be applied to the HERMES propulsion subsystem. The resultantmeasurement points with their data requirements and the new technologicaldevelopments needed are described in the third part of this paper.

DOC. NUMBER: 71

TZTLE: The History and Future of Safety Monitoring in Liquid RocketEngines

AUTHOR: A. Norman, I. Cannon, L. Asch; Rockwell International,

Rocketdyne Division

PUE LISR: AIAA

DATE: July 1989

DOC. TYPE: Conference Paper

ABSTRACT: One of the major advantages of liquid rocket engines is theirability to modify operating conditions during a firing in order to preventfailures which might otherwise result in loss of the mission or damage to testfacilities. The simplest and most common form of modification is shutdown,but transitioning to a more benign condition for a detected problem is likelyto become more conmon in future engines as new and more powerful controlhardware and software become available. In order to take advantage of thiscapability, monitoring systems must be able to detect unsafe conditions andsignal the control system to take the appropriate actions. This paper willdiscuss the history and development of these safety monitoring systems to thepresent day, what can be expected in the foreseeable future, and how pasthistory can affect these expectations.

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DOC. NWU03R: 72

TITLX: Integrated Health Monitoring Approaches and Concepts forExpendable and Reusable Space Launch Vehicles

=UTHOR: J.G. Johnson; General Dynamics Space Systems Division

PUBLISBRR: AIM

D=: July 1990

DOC. TYPE: Conference Paper

ABSTRACT: To support the high launch rates that are projected for spacelaunch vehicles in the 1990a and to reduce current launch system operationscosts, test and checkout tasks will have to be accomplished in a more cost-effective and operationally efficient manner. This paper will determinehealth monitoring approaches and concepts for expendable and reusable spacelaunch vehicles, and provide a definition and architecture for integratedhealth monitoring. Expendable space launch vehicle flight history data isalso presented to further understand the types of anomalies that have occurredon past space launch systems. A vehicle data architecture is also presentedfor reviewing data and obtaining the maximum amount of information that isavailable onboard a space launch vehicle system. Information is alsopresented concerning the technology issues for a fully integrated healthmonitoring system, as well as the evolutionary trend that is occurring betweenthe ground support equipment and airborne areas.

DC. NM : 73

TITLZ: Neural Network Approach to Space Shuttle Main Engine HealthMonitoring

AUTHOR: B. Whitehead, H. Ferber, M. Ali; Center for Advanced Space

Propulsion, University of Tennesse Space Institute

PUBL SUR: AIAA

D=: July 1990

DX. TYPZ: Conference Paper

ABSTRWT: A neural network was trained to distinguish anomalies in SSMEsensor data from noisy normal steady-state sensor data. Power spectra ofsuccessive windows of individual sensor data were presented to a neuralnetwork using Kohonen's topological feature map training algorithm. Thetrained network for each sensor was then tested to determine if it woulddetect anomalies in the sensor data, and if so, the time at which the anomalywould be detected. Power spectra from a few hundred seconds of actual testdata from NASA tests 901-364 and 904-044 were used to test the network. Inboth cases, the neural a~etwork detected the onset of anomalous engine behaviorat approximately the same time within each test as the onset times reported byNASA and Rocketdyne exp rts in their post-test analyses.

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DOe. NWIUR: 74

!ZTLI; Neural Network Pattern Recognizer for Detection of FailureModes in the SSME

AUTROR: H. Luce, R. Govind; NASA, Health Monitoring Technology Center,University of Cincinnati

PUBLISHER: AIAA

DATI: July 1990

DOC. TYPZ: Conference Paper

ABSTRACT: A system for diagnosis of emergent performance degradations andfailure modes in the SSME is described. This system looks at the SSME as acollection of subassemblies, and uses time signature data, from sets ofparameters arising from sensors local to each subassembly, to compose patternsto be analyzed, A hybrid architecture is used: The first processing layerconsists of ART2 (adaptive resonance theory) neural networks, one ART2 networkper subassembly; the second layer consists of CAM (content addressable memory)networks, one per subassembly; and the final layer is a backpropagation neuralnetwork, which processes data from all of the CAM networks. A prototypesystem, encompassing only the high pressure fuel turbopump, is presented. Thelong-term goal of this work is to create a system using the above architectureto ensure that the SSMS remains in a state of "health," by creating a feedbackloop incorporating operating parameter controls, subassemblies, sensors, andthe neural network system.

DOC. NUMMR: 75

TZTLZ: Prelaunch Expert System for Space Shuttle Propulsion SystemHealth Monitoring

hDTBOa: J. Engle, D. Bogart, J. Marinuzzi; Rockwell InternationalCorporation, Space Transportation Systems Division

PUDZSMR: AIAA

DAME: July 1990

DOC. TYPK: Conference Paper

ASTPACT: The prelaunch expert system is a ground-based real-time expertsystem used to monitor sensors for each Space Shuttle subsystem and identifylaunch commit criteria violations, their causes, and suggested courses ofaction. This expert system will reduce the workload and enhance theperformance of engineers who monitor large amounts of data and will speed uptheir reaction time to potential problems. Xn addition, it can preservevaluable Shuttle program knowledge that might otherwise be lost with theretirement or transfer of senior personnel. The building of the system wasdriven by the needs of the mission support comunity and has therefore found ahigh degree of acceptance among its intended end Users.

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DOC. NUMME: 76

TZTLE: Progress Toward an Automated Visual Inspection System

AUHTOR: P. Coleman, S. Nelson, J. Maram, A. Norman; RockwellInternational, Rocketdyne Division

PULISBZR: AIAA

DATE: July 1990

DOC. TYPE: Conference Paper

ABSTRCT: This paper discusses current trends in the automation of visualinspections for reusable rocket engine systems. The application of automatedinspection methods for between-flight maintenance and manufacturing isdiscussed. In addition, the application of vision processing to imagesacquired by current methods of visual inspection is examined.

DOC. N MER: 77

TITLE: Rocket Engine Diagnostics Using Neural Networks

AUTOR: B. Whitehead, E. Kiech, M. Ali; Center for Advanced SpacePropulsion, University of Tennessee Space Institute

PU DL S R: AIAA

DUE: July 1990

DOC. TYPE: Conference Paper

ABSTRACT: Two problems in applying neural networks to fault detection andidentification are (1) the complexity of the sensor data to fault mapping tobe modeled by the neural network, which implies difficult and lengthy trainingprocedures; and (2) the lack of sufficient training data to adequatelyrepresent the very large number of different types of faults which mightoccur. Methods are derived and tested in an architecture which addressesthese two problems. First, the sensor data to fault mapping is decomposedinto three simpler mappings which perform sensor data Compression, hypothesisgeneration, and sensor fusion. Event training is performed for each mappingseparately. Secondly, the neural network which performs sensor fusion isstructured to detect new unknown faults for which training examples were notpresented during training. These methods were tested on a task of faultdetection and identification in the SSME. Results indicate that thedecomposed neural network architecture can be trained efficiently, canidentify faults for which it haq been trained, and can detect the occurrenceof faults for which it has not been trained.

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DOC. NUMBER: 78

TITLE: Role of Microstructural Sensors for Space Propulsion HealthMonitoring

AUTHOR: H.T. Henderson, W. Hsieh; Department of Electrical andComputer Engineering, University of Cincinnati

PUBLISHER: AIAA

DATE: July 1989

DOC. TYPE: Conference Paper

ABSTRACT: The University of Cincinnati was assigned one of the new NASAresearch centers through a national competition held last year. The area ofresearch here is health and condition monitoring for space propulsion.

This area of research is composed of five major subsets: materials modeling;algorithms and control; structural dynamics; flow and propulsion; and sensors.

It is the purpose of this paper to broadly describe the sensors thrust, withan example or two, in order to provide a perspective of the direction andpossibilities of this effort. Most specifically, a microflowsensor will bedescribed to illustrate the power of "micromachining" for creation ofminiature, smart, affordable, and reliable sensors which might be placed inlocations where parameter monitoring has been previously impossible.

The microsensors and semiconductor microstructures group is now workingprimarily with mechanical structures at the mil (thousandths of an inch)level, but with our optical and electron beam facilities and our newnanostructuros lab, we are set for dimensional progress over the comingdecade.

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DOC. NWZR: 79

TITLZ: Selection of Monitoring Techniques for a Liquid PropellantRocket Engine

A = OR: E.P. Jurado, J.B. Shade, M.A. Weise; Pratt & Whitney

PULISmR: AIAA

DM: July 1990

DOC. TYPE: Conference Paper

ABSTRACT: Methodology for selecting a liquid propellant rocket enginecondition monitoring system has been developed as part of the rocket enginecondition monitoring system program under contract from the United States AirForce. This paper describes the development and use of procedures whichevaluate gas generator rocket engine failure modes and associated costs toselect monitoring techniques for fault detection and the prevention of faultpropagation. An expert system computer program has been developed to selectan optimum health monitoring system based on potential life cycle savings.This methodology determines the effects of incorporating an engine monitoringsystem on costs associated with catastrophic future, mission scrub, launchdelay, scheduled and unscheduled maintenance action, ground support equipment,engine shutdown, sensor false-flag, algorithm development, and development andproduction of monitoring techniques. The health monitoring system identifiedby these methods establishes the required sensors, algorithms, ground supportequipment, and signal processors along with the failure modes and engineparameters that become monitored with their selection. Implementing thismethodology will result in improvements in both mission success reliabilityand system life cycle cost.

DOC. N IZR: 80

TZTLR: Validation Requirements for a Rocket Engine Control andMonitoring System

AIUB=: A.M. Norman, Jr., J. Maram, A. Weiss; Rockwell International,

Rocketdyne Division

PUBISUR: AIM

DAU: July 1990

DOC. TYPE: Conference Paper

ABSTRACT: This paper discusses the requirements for a validation system forrocket engine CMS and why one is needed in the near term. There is animplicit assumption that although failures (perhaps multiple failures) are aprobabilistic outcome, the consoquence of failure must be a well-knowndeterministic Eunction, mainly for political reasons. The proposed solutionis an engine simulation program sufficiently sophisticated to model thefailure modes of interest.

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a.3 TZC1OLOGT

DOC. NMOI: 81

TZTLE: Analysis of Airframe/Engine Interactions - An IntegratedControl Perspective

AUTHOR: D.K. Schmidt, J.D. Schierman; Arizona State UniversityS. Garg; Sverdrup Technology Inc.

PUBTLISER: AIAA

DATE: July, 1990

DOC. TYPE: Conference Paper

ABSTRACT: Techniques for the analysis of the dynamic interactions betweenairframe/engine dynamical systems are presented. Critical coupling terms aredeveloped that determine the significance of these interactions with regard tothe closed loop stability and performance of the feedback systems. Aconceptual model is first used to indicate the potential sources of thecoupling, how the coupling manifests itself, and how the magnitudes of thesecritical coupling terms are used to quantify the effects of theairframe/engine interactions. A case study is also presented involving anunstable airframe with thrust vectoring for attitude control. It is shown forthis system with classical, decentralized control laws that there is littleairframe/engine interaction, and the stability and performance with thesecontrol laws is not effected. Implications of parameter uncertainty in thecoupling dynamics are also discussed, and effects of these parametervariations are demonstrated to be small for this vehicle configuration.

DOC. NMZR: 82

TITLE: Engines and Artificial Intelligence

AUT!OR: Len Buckwalter

PURDI:SZR: Avionics

DM : February 1986

DOC. TYPE: Magazine Article

ABSTRAC: GEN-X is a software package that enables experts, possessinq just abasic familiarity with computers, to devise their own systems by inputtingtheir knowledge and experience for troubleshooting. The firt application ofthis software was computerizing the troubleshooting of locomotives in railroadservice shops. Other early applications include maintaining the pitch controlof the F-15 flight control system and diagnosing gas turbine faults.

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DOC. NMMZR: 83

TZTLZ: Propulsion System-Flight Control Integration-Flight Evaluationand Technology Transition

AUTHOR: F.W. Burcham, G.B. Gliyard, L.P. Myers; NASA Ames ResearchCenter, Dryden Flight Research Facility

PUBLISBER: AIAA

DATZ: July 1990

DC. TYVZ: Conference Paper

ABSTRACT: Integration of propulsion and flight control systems and theiroptimization offers significant performance improvements. The NASA AmesResearch Center, Dryden Flight Research Facility has, over the years,conducted research programs which have developed new propulsion and flightcontrol integration concepts, implemented designs on high-performanceairplanes, demonstrated these designs in flight, and measured the performanceimprovements. These progrms, first on the YF-12 airplane, and later on theF-15, have demonstrated increased thrust; reduced fuel consumption; increasedengine life; and improved airplane performance, with improvements in the 5- to10-percent range achieved with integration and with no changes to hardware.The design, software and hardware developments, and testing requirements havebeen shown to be practical. This technology has been transferred to the usercommunity through reports, symposia, and industry cooperative programs, and isappe&Ting on operational and advanced airplanes. The flight evaluation anddemositration have been shown to be key in maturing the technology andhastening its tx.nsition into production.

DOC. NWMR: 84

TITLZ: Oil Debris Monitoring

AUTHOR: .- M. Selman, -Tedeco Division, Aeroquip Coporation

PUBLUShER: Avionics.

DMT!: rebrijary 1986

DOC. TotK t vgazt Article

I58TPJ=* r'aiure of rechatical 3ystmz. auch as trans-wissions is usuallypreceded by a. incoaa. in the number and size of particles in Ithe lubricatingoil. Four -,pea of tft-nsors fok- detecting thtse particles are discussed itfthis arti . ; t a collector se0or, a m ,net is vithdrnm for inspectionperiodically. The second type of sensor ati elec ric detector, rese3bles aspark plug, A patticle thorts the detector and in fact the tensor can detectone parl_.l:I. The third type of aensor, a pulsed eleii.c detector, isdin.lar L the secead ounsori but small particles or, pariodic.ly blown Awayby a ctrtent pulse. The sentot can count small particlo, Wt the seaonsfails with a big Iarticle. The final senator is a cuant 4tativ debris ,monior4QD3), which magnetically covnts and sizes particles. This sensor pgovidesthe beat results, but with the "ost Cost.

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DWC. NUZ3M: 85

?TNA: Vibration Monitoring

uDTMo: J. Higgins, Charles Witt; £ndevco-Corporation

PODLZSB3F: AvioniC3

DM~: February 1986

DOC. VMS: Magazinie Article

flBSTRCT: Vibration monitoring of a turbine eng~ine is a problem, since aturbine engine produces mechanical vibration amplitudes at virtually allfrequencies in the audio range. A vibration monitoring system mustdiscriminate between engine vibration at frequencies of interest and vibrationat other frequencies. The monitoring problem i3.:compounded by the fact thatvibration frequencies from a turine engine are not constant; as powerincreases or decreases, rotating elements correspondihqly change speed.Simple vibration monitoring 4ysteMs, therefdre,'are often designed to acceptany signals within the operaeiOnZJ. speed of the engine. An efficient iystemaccepts signals from engine tachomeaters which then control the centerfrequency of the bandpass trackcing filters. A filter which can trackfrequienci.es of interest does not-hoed to bei very wide in frequency and is veryeffective in rejecting unwanted vibratlon #igna.

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DOC. USER: 86

TITLE; The Application of an Expert Maintenance and Diagnostic Toolto Aircraft Engines

AUTHOR: Dr. R.L. De Hoff, L. Miller, J. Frenster; Systems ControlTechnology, Inc.

PUBLISHER: AIAA

DATE: July 1990

DOC. TYPE: Conference Paper

ABSTRACT: Next generation aircraft and engines will have the capability todetect, isolate, and accommodate failures in components and subsystems whilein flight. To completely realize the full benefits of weapon systemintegrated diagnostics, intelligent systems must be developed to assistmaintenance personnel in servicing the aircraft efficiently and correctlywhile on the ground.

This paper describes experiences gained in developing and fielding expertmaintenance and diagnostics systems for modern aircraft engines.Specifically, SCT's expert maintenance tool (XMAN) has been developed forseveral USAF and USMC engines. The architecture and functionality of XMAN arediscussed and its applicability to future engines is presented. Lessonslearned are derived which address issues of knowledge acquisition, maintenancetraining, and insertion into the logistics support infrastructure.

DOC. NUMBER: 87

TITLE: EPAMS - Engine Performance Assurance Monitoring System

AUTHOR: Howell Instruments, Inc.

PUBLISHER: Howell Instruments, Inc.

DATE: September 1988

DOC. TYPE: Product Brochure

ABSTRACT: The microprocessor-based H598 EPAMS monitors engine parametersconstantly during all flight operations while calculating theoretical engineparameters for flight conditions as a basis of comparison to actualperformance and performs real-time analysis of engine operation.

EPAMS provides the following engine documentary data: engine usage, missionprofiles, parts-life tracking, and an automatic history of all limitexceedances. EPAMS will record the number of engine starts, time at maximumpower, time above selected levels of performance for up to 22 differentvalues, total engine time, and engine cycles. EPAMS will also detect enginemisuse or abuse through its data logging ability.

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DOC. NWIZR: 88

TITLE: On Condition Eagine Monitoring

AUTHOR: G. Tonnison; Basingstoke Division, Smiths Industries

PUBLISHER: Avionics

DATE: February 1986

DOC. TYPE: Magazine Article

ABSTRACT: Currently, aircraft engines are scheduled for overhaul rather thanhaving mairtonance performed on-condition. On-condition maintenance requiresthat equipment be removed for overhaul when specified deterioration isidentified. Engine monitoring could reduce the risk of on-conditionmaintenance to acceptable levels. Systems exist for aircraft enginemonitoring as well as for rotary-wing aircraft. A typical monitoring systemprovides facilities in six broad groups: life usage and exceedance;performance-data recording; incident recording; vibration analysis; BITE; andexternal communications. From these facilities, several analyses areavailable: low cycle fatigue, thermal fatigue; creep; time/temperature; timespeed; gas path analysis; and oil debris monitoring.

DOC. NUMBR: 89

TITLE: Helicopter Operators Forecast Steady Growth into Mid-1990s

AUTHOR: N.C. Kernstock

PUBLISHER: Aviation Week & Space Technology

LATE: February 1990

DOC. TYPE: Magazine Article

ABSTRACT: The global civil helicopter industry has experienced a rebound,althovgh business has not yet returned to the high levels seen in the late1910s. Four operators typify those who are achieving success by controllingthe growth of existi.ng business and their entry into new mArkets, as well asexploiting profitable niches. While these companies' operations encompass awide variety of helicopter missions, three major markets are responsible formost of the growth: the oil industry, police and public service, and medicalfliqgt service.

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DOC. NMBDR: 90

TITLE: TRENDKEY

AUTHOR: Keystone Helicopter Corporation

PUBLSHR: Keystone Helicopter Corporation

DAT: 1987

DOC. TYPE: Product Brochure

ABSTRACT: TRENDKEY is a self-contained panel-mounted system that providesoperators with a real-time display of aircraft performance during all flightoperations. TRENDKEY can also be interfaced with other avionics and systemsto monitor, analyze, and display fuel, air data, and navigationalinformation.

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