CP- 448
`
`22-1
`
`COMMERCIAL ENGINE MONITORING STATUS AT GE AIRCRAFI‘ ENGINES
`CINCINNATI, OHIO
`
`by
`
`-
`
`R.J.E..Dyson
`er, Monitoring Systems Engineering
`General Electric Company, Aircraft Div.
`1 1 1 Merchant Street, Room 343
`Cincinnati, OH 45246, USA
`and
`
`Jfilmm
`Manager, Condition Monitoring Programs
`Airline Support
`General Electric — Aircraft E1?.11es
`1 Nenmann Way, Mail Drop :40
`Cincinnati, OH 45125, USA
`
`SUMMABI
`
`introduction and development of expanded
`This paper describes the design,
`commercial engine monitoring systems by GE Aircraft Engines.
`The history of
`present systems is outlined starting from the introduction on the CF§—80A3 engine
`for the A310 aircraft of the Propulsion Multiplexer (PMUX) which has led to similar
`systems on the CF6—80C2 engine.
`The impact of the full authority digital control
`on future system is also discussed.
`a
`
`The introduction and application of the Ground-based Engine Monitoring (GEM)
`software developed by GE in conjunction with several airline users is recounted.
`This is an on—going team effort with the users playing a key role and where
`individual airlines have added unique features.
`integrated with GEM,
`into their own
`operations.
`The original software development occurred in parallel with the
`expanded sensor complement and digitization of data.
`A description of the
`functions of a typical ground software program is provided together with proposed
`improvements and future directions.
`
`LEIEQDHCIIQH
`
`The introduction of "on condition" maintenance concepts for high bypass
`turbofan engines encouraged the use of advanced engine monitoring techniques.
`Although GE had participated in several monitoring programs to support the CF6-6
`and CF6-50.
`the CF6—80A3 engine on the A3l0—200 aircraft for KLM and Lufthansa
`Airlines was the first to be equipped with expanded capabilities. These
`capabilities included sufficient instrumentation for modular performance
`assessments, an expanded aircraft data system and an analytical ground software
`program.
`
`Many airlines have in fact utilized engine monitoring techniques for a number
`of years. driven by the introduction of Pon-condition" concepts in the late
`l960's.
`Initially. expanded instrumentation complements resulted in widespread
`systems problems. many associated with the transmittal of analog signals over long
`distances in aircraft.
`The introduction of the PMUX on the CF6—80A3 engine. with
`the associated transmittal of highly accurate. reliable digital data, was a key
`factor in making the expanded engine monitoring approach work.
`The functions of
`the PMUX are now being incorporated into the new generation of full authority
`digital electronic controls with resultant reduction of unique monitoring hardware
`and software. yet with a further expansion of capabilities.
`
`The ground-based engine condition monitoring (GEM) software for many GE and CFM
`International powered aircraft is described. This GEM system provides the
`capability to monitor and analyze a wide range of engine thermodynamic and
`mechanical measurements with a single. flexible computer program.
`
`BOEING
`Ex. 1019
`
`

`
`22-2
`
`Measurements acquired with the standard engine instrumentation as well as
`extended monitoring instrumentation if available. are recorded during normal engine
`operation. These data are generally stored for subsequent retrieval using an
`on-board data acquisition system.
`The data recorded during flight. along with test
`cell performance measurements. are input into the airline's computer system for
`ground—based processing with the GEM system.
`The results from the GEM processing
`are made available to various airline organizations in order to monitor and manage
`the engines within their fleet.
`
`The GEM monitoring system is designed to provide an airline with a valuable
`tool with which to manage its aircraft engines relative to such concerns as safety.
`availability. maintainability. fuel costs. and improved performance.
`
`Directions for the future show that some of the functions which are presently
`performed on the ground will be performed airborne where useful
`to flightline
`operations. Airborne diagnostics will be enhanced and results, rather than raw
`data. will be transmitted across the avionics data bus thus making available to the
`line mechanic useable information for accomplishment of his maintenance tasks.
`The
`paper concludes with a discussion of these future plans for commercial engine
`monitoring and current operational experience.
`
`§I§[£fl DESQRIPTIQQ
`
`-
`
`UT
`
`The PMUX was developed to provide consistent. accurate data suitable for gas
`path analysis or modular fault isolation.
`It is a convection—cooled.
`microprocessor-based unit which houses pressure transducers. signal conditioning
`and analog to digital conversion.
`It has extensive built—in-test and signal
`validity checks. All of the signals critical to the gas path analysis/modular
`fault isolation function are routed through the PMUX to maintain consistent.
`accurate data. other than Ni. TMC and TLA. which are processed by the Power
`Management Control
`(PMC) and made available on the digital data link.
`
`CF6—80 Condition Monitoring Parameters
`
`
`
`
`
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`r F‘
`
`
`
`P49
`
`
`
`Also: N1, N2. WF. TMC. TLA. TNAC and Vibe (2) plus
`aircraft parameters PO, TAT and Mach No.
`
`Figure 1
`
`The instrumentation complement for the CF6-BOA3 engine is shown in Figure
`No. l.
`Instrumentation for the CF6-8002 is essentially the same. These sensors
`can be sub-divided into the following categories:
`
`BOHNG
`Ex.1019
`
`

`
`22-3
`
`A. Signals required for indicationlcontrol purposes and routed through the
`Propulsion Multiplexer (PMUX) or Power Management Control
`(PMC):
`—
`Fan Speed (Ni)
`Core speed (N2)
`Throttle Lever Angle (TLA)
`Fuel Flow (NF)
`Main Fuel Flow Torque Motor Current
`LP Turbine Inlet Temperature (T49)
`
`(TMC)
`
`B. Agdigional signals required for Engine Monitoring which are routed through
`t e MUX:
`—
`Fan Discharge Static Pressure'(P$J4)
`Compressor Inlet Pressure (P25)
`Compressor Inlet Temperature (T25)
`Compressor Discharge Static Pressure (PS3)
`Compressor Discharge Temperature (T3)
`LP Turbine Inlet Pressure (P49)
`LP Turbine Discharge Temperature (T5)
`variable Bypass Valve Position (VBV)
`- Variable Stator Vane Position (VSV)
`
`C. Additional signals required for Engine Monitoring but not routed through
`the PMUX or PMC:
`-
`#1 Bearing (Fan) Internal Accelerometer
`— Alternate Fan Frame External Accelerometer (Optional)
`s
`compressor Rear Frame External Accelerometer
`- Nacelle (core compartment) Temperature (TNAC)
`
`D. Aircraft parameters required for engine monitoring (not including anti—ice
`and bleed discretes):
`- Pressure Altitude (P0)
`Total Air Temperature (TAT)
`: Aircraft Mach No.
`(MN)
`- Other instrumentation available as part of the inflight data record
`consisting of oil
`temperature. oil pressure and oil quantity.
`
`The interfaces with the PMUX and PMC are shown in Figure No. 2.
`
`CF6-80C Fan Compartment Interface T
`Wiring and Connector Schematic
`':
`Airorait connector
`3- GE condition monitoring connector
`D- GE performance and oontroie oonneoior
`D- GE naoeile oonneoior
`
`
`
`W GE condition monitoring PMUX kit
`Supplied equipment
`Not shown are P814. P25. P49, and PS3
`Froi:-esfedaptorc
`
`
`
`BOEING
`Ex. 1019
`
`

`
`22-4
`
`leads are combined in a
`The PMUX is mounted on the engine fan case. Electrical
`harness and routed from the core to the fan compartment and to the PMUX.
`The
`pressure sensors (sources) are connected by tubing to the pressure transducers
`which are contained within the PMUX unit.
`In addition a raw N2 (core) signal
`routed to the PMUX and an ARINC data link connects the PMC to the PMUX. Thus.
`PMUX accepts analog and digital inputs from various added and existing engine
`sensors. These inputs are conditioned. multiplexed. and converted to digital
`format
`(ARINC 429) for output to the Aircraft Integrated Monitoring System (AIMS).
`
`is
`the
`
`lanyarded to the fan
`In addition. an encoded Engine Serial Number plug (ESN),
`case.
`interfaces with the PMUX and provides the means for "Tagging" acquired data
`with the appropriate engine serial number.
`
`A more detailed description of the hardware is contained in Ref. 1.
`
`Instrumentation for the Full Authority Digital Controlled (FADEC) CF6-80C2B
`lFIDIF and CFM56-5 is similar to that described above. but the system no longer
`requires a separate PMUX.
`The functions of the PMUX are contained within the FADEC
`which provides the signal conditioning and the digital
`interface with the aircraft.
`The parameters which required an analogue interface (e.g. vibration) still require
`that interface in this first generation of FADEC controlled engines.
`It is
`anticipated that future applications, such as the GE36 engine for the UDFTM, will
`possess a purely digital
`link with the aircraft.
`(See Figure No. 3).
`The majority
`of the engine monitoring, fault isolation and detection will be performed on
`engine.
`Space and flexibility considerations are presently dictating that there be
`two on—engine boxes, one for control and flight critical purposes and the other for
`engine monitoring.
`
`Option for Proposed Advanced System
`
`Eng.ah.pmu
`
`Critical param.
`
`All others
`
`
`
`EMS data
`
`sunage
`
`
`
`Signals
`
`Optional
`expanded
`Param.
`
`(Module analysis)
`
`Figure 3
`
`
`
`The Ground-based
`The flow of engine monitoring data is shown in Figure No. 4.
`Engine Monitoring (GEM) system provides the capability of handling a wide range of
`engine thermodynamic and mechanical functions (see Figure No 5) within a single
`very flexible program.
`The software was developed as a co—operative effort
`involving GE and a group of airlines (originally KLM, Lufthansa and SAS).
`resulting design is shown in Figure No. 6.
`
`The
`
`BOEING
`Ex. 1019
`
`

`
`Schematic of Engine Monitoring
`information Flow
`
`22-5
`
`.V o
`
`PMUX/F-‘DEG
`
`Data Acquisition
`[AIMS]
`
`On-B-card
`Ezoflwern W
`— Eerludic Heparin n
`— 0:: Fling: aft?-En:
`Fleportsic aaselle/ACAFIS
`I
`
`
`
`Ale 5
`L2_‘_fih:$';|‘Ir
`
`in
`
`rs ; Manes
`-.'I . I'D
`GEM Ansltr-Ill
`— MLIIIIDIB
`f-‘u
`l
`|'|0| MI
`
`Figure 4
`
`" %
`Dam
`input In
`Ground-bum:
`
`computer
`
`
`
`On-wing temper*
`
`Test cell temper*
`
`Analyze cruise gas path data to determine overall
`engine and module health
`
`
`
`Analyze acceptance test gas path data to detennlne
`overall engine and module health
`
`Takeoff margin assessment
`
`Analyze takeoff data to determine the EGT margin of
`the engine
`
`Control schedule analysis
`
`Ground-based Engine Monitoring System
`Analysis Functions
`
`
`
`
`
`
`
`Compare measured control variables to nominal
`schedules and limits
`
`
`
`Vibration trend analysis
`Compare measured vibrations to limits to Identify
`potential imbalances
`
`
`
`
`
`Fan rotor imbalance
`
`Use measured tan vibration amplitude and phase angle
`to determine balance weights to correct tan imbalance
`
`Fleet average
`
`Compute fleet statistics for engine family and
`identify low performing engines
`‘For turbine engine rnoduie porlorrnurrca estimation routine
`
`
`Figure 5
`
`BOEING
`EX. 1019
`
`

`
`22-6
`
`GEM Software System Architecture
`
`f"§
`
`\
`
`3
`
`_
`
`
`/
`CI 1Us|er
`\
`a cu ations
`E9
`\‘H ’ /.
`Installed \ Amine
`
`
`Configuration
`_
`Ed"'”9
`data
`
`
`Program
`
`
`
`
`Generate
`“Airline Input
`
`File"
`
`
` ° Jill“ 1“. .''o
`
`
`Trend plots. etc.
`
`Maintenance reports
`
`Alert Message
`
`Figure 6
`
`take-off margin.
`The GEM program monitors and analyzes performance trends,
`In addition. it
`control schedules, vibration trends and fan rotor imbalances.
`incorporates the Turbine Engine Module Performance Estimation Routine (TEMPER). a
`program used to diagnose engine modular performance in airline test cells.
`GEM
`extends the TEMPER program to the analysis of installed cruise data in order to
`provide modular performance estimates and trends.
`
`The GEM system started as a GE/Airline team effort for the CF6—80A3 engine on
`the Airbus A310-200 aircraft.
`GE Aircraft Engines. KLM. Lufthansa and SAS. along
`with Airbus Industrie, worked together to define. develop.
`implement and refine
`this extensive monitoring system.
`CFM International and other airlines using GEM
`have joined this effort during recent years. GE's participation has included the
`development of the GEM nucleus of analytical functions. within a mutually agreed
`software structure.
`to manage the data flow.
`A general architecture for GEM is
`shown in Figure No. 7.
`On the airline side, each user has developed individual
`
`GEM Software Architecture
`
`
`
`
`
`Perionn analysis
`functions and
`store results
`
`
`
`Retrieve
`current and historic
`data for
`calculations
`
`
`
` Periorm
`Date compression
`
`It needed
`Fleet
`
`average
`tile
` and store
`
`
`fleet averages
`
`Figure 7
`
`BOEING
`Ex. 1019
`
`

`
`22-7
`
`software to pre-process the engine data and has defined output display formats in a
`manner compatible with their own operation. Further.
`they have contributed to the
`overall design and implementation of the system.
`A description of implementation
`of GEM monitoring at KLM and Lufthansa can be found in Ref. 2 and Ref. 3.
`
`As the GEM program has been implemented the airlines have started to rely on
`alert sumary reports to monitor the engine trends for their fleets instead of
`daily examination of individual
`trend charts.
`The engine trend analyst at each
`airline interrogates the alert summaries and can obtain supplemental
`information
`using a menu of available plots in order to investigate any particular alert.
`Generally. previous trends for the engine are retrieved from the airline's history
`files. which might include codes indicating maintenance performed on the engine.
`Based on this examination,
`the analyst will
`recommend appropriate actions. Efforts
`continue to fine-tune the trend recognition routine in order to reduce some of the
`unnecessary alerts.
`
`Another significant advance is the use of cruise acquired vibration data to
`perform fan trim balances without expensive ground runs. Lufthansa has
`successfully used this procedure to balance their CF6-80A3 fans to keep fan
`vibrations well below limits using an auxiliary PC program which they developed and
`which will be incorporated in GEM at a later date.
`The benefit to Lufthansa.
`in
`addition to the avoidance of ground runs. is extended life for accessories and
`parts (such as brackets) which are affected by high vibration.
`In this system.
`both fan vibration amplitude and unbalance phase angle are acquired during cruise.
`Back on the ground.
`these data are used to project appropriate weight changes;
`these are done by changing the configuration of the balance bolts. when fan
`vibration trends increase,
`the airline can make corrections based on cruise data
`alone. without extensive (and expensive) ground operation. Similarly. engine
`control parameters -- Variable Stator Vane (VSV) setting, Variable Bypass valve
`(¥g¥)1position. and torque motor current -- are monitored to promote maximum fuel
`e
`c ency.
`
`Some Airlines have added a number of features to integrate the GEM system with
`their own operations. These include features to process, store and present GEM
`data automatically.
`KLM retrieves data from their on-board system using cassette
`tapes containing data sampled throughout the flight from which readings are
`selected for batch GEM processing. Lufthansa. on the other hand, uses optical
`scanners to read data from its on-board system's printed reports;
`these are then
`loaded into the main computer via their worldwide reservation system. Lufthansa
`has thus developed a virtual real-time system in which GEM results are available to
`their analyst within a few hours of the airplane's landing. These GEM results are
`also available to GE via a direct data link, provided by Lufthansa. between the GE
`Product Support Center in Cincinnati and Frankfurt. Germany.
`
`GEM was originally designed for the CF6—80A3 in the A310-200 application but it
`has been expanded over a period of years to incorporate various GEICFMI engines and
`applications.
`the latest of which is the CFM56—5 in the A320 (see Figure No. B).
`The prime purpose of the latest software release is to include this first FADEC
`controlled engine as part of what is now known as "universal" GEM.
`Instrumentation
`limitations on certain engines do not allow for the implementation of all
`analytical functions to all engines.
`The functions available by engine model are
`shown in Figure No. 9.
`
`PERATI
`
`EX
`
`E
`
`Considerable operational experience has been obtained from the CF6-80A3
`engine. This experience is now being extended with the CF6-80 and CFM56 families
`of engines.
`A number of problems have occurred all of which have been addressed in
`latest releases.
`
`0
`
`Pressure transducers were affected by service generated contamination and
`moisture. Design changes to the transducer and pressure tubes were
`required in order to overcome the problem.
`
`BOBNG
`Ex.1019
`
`

`
`22-8
`
`Latest GEM Engine/Aircraft Applications
`
`
`
`CF6-80A3
`
`A300 A300 A310
`-200
`-800
`-200
`
`B737 B747 B747 B767 DC-10 A310
`-300
`-200
`-300
`-300
`-30
`-300
`
`
`
`CF6-8002
`
`CF6-50C/C +
`
`
`
`CF6—5OC2
`
`CF6-50E2
`
`CFM56-3
`
`CFM56-5
`
`Figure 8
`
`Universal GEM Analytical Monitoring Functions
`nmzmaam
`Yes
`Yes
`On wing
`rformance
`analysis 8?
`Test cell performance
`analysis
`TIO EGT marglnl
`SLOATL (2)
`SLOATL with cruise
`update
`Engine controls (2)
`Vibration trending (2)
`Fan rotor imbalance (2)
`Reduced ian speed
`summary
`Oil monitoring (AIMS)
`Umlt exceedance
`Trend reoognlilon
`Miscellaneous alerts (2)
`Fleet average
`Simulation
`
`Necelle temperature
`
`NIA Not ap1:llcui.:Iro
`1)
`Instrumentation oonilguration limits level oi module analysis
`2) 0:
`‘ng
`I
`(3) Tremhggtgmfly (no modulo nnwels)
`
`(4) Two ol tour pceaibie vibration signals
`(5) Vibration amplitude rid phaal
`hmoterlstics ot established
`(6) Test cull only
`I
`ma 0
`"
`Figure 9
`
`0
`
`0
`
`0
`
`0
`
`Low input impedance cockpit instrumentation affected the shared EGT signal.
`
`Incompatibiiities were generated due to late and seemingly insignificant
`design changes between the LVDT sensor and the PMUX which provides
`excitation and signal conditioning.
`
`Initial software trend shift recognition and alerting features produced an
`unacceptable number of false or unnecessary warnings to the airline
`analysts. These continue to be refined based on operating experience.
`
`Initial cruise trends exhibited an unacceptable amount of scatter.
`Replacement cruise reference baselines were required which better matched
`the engine operating characteristics in revenue service.
`
`BOEING
`EX. 1019
`
`

`
`22-9
`
`Lufthansa are reporting quantifiable savings through diligent use of the
`system.
`It is reported that early failure detection. reduction in the number of
`line station removals. optimum scheduling, "cold" fan trim balancing and improved
`engine/module management are providing reductions in material, manpower,
`maintenance. fuel and overhaul repair costs. other non-quantifiable benefits are
`also reported such as reduced out-of-service time. reduced secondary damage.
`improved flight safety standards.
`improved troubleshooting and the ability to
`handle large fleets.
`t‘A1number of recommendations can be made in terms of general monitoring system
`v ty:
`
`ac
`
`Hardware;
`
`0
`
`o
`
`0
`
`The engine monitoring program should be established up front. Design of
`auxiliary systems subsequent to design of the basic engine and
`configuration hardware adds expense and “less than best“ compromises.
`
`including the off-engine software. should be
`The engine monitoring system.
`approached just like any other engine sub-system.
`It should be included on
`all factory and flight test engines and certified like any other engine
`su —sys em.
`
`A thorough analysis of electrical characteristics both between components
`within the system and between the various interfacing aircraft systems is
`essential. Certain sensors and instruments are sometimes derivatives from
`earlier systems and are included to maintain commonality of hardware.
`Their operation in the new system can prove to be incompatible. Use of
`cockpit instrumentation with low input impedance characteristics must be
`avoided.
`
`Software;
`
`Sufficient time must be provided to develop and check out such a software
`system between the definition of the specification requirements and the
`implementation in a production environment.
`
`Development of a new software system concept will benefit from initial
`prototype application to gain operating experience which can be used to
`finalize the software design.
`
`A design/development team with strong airline participation can address the
`real operating conditions and requirements for the monitoring system.
`The
`system's value will
`thereby be greatly enhanced.
`
`Too much initial flexibility and optional operating modes slows down
`development and can overwhelm new users.
`
`Standard and rigid interfaces are required for the software system.
`
`It must be possible to refine the system as operation experience dictates.
`
`o
`
`o
`
`0
`
`o
`
`0
`
`0
`
`EUIURE
`
`Military and commercial operators have traditionally taken different approaches
`to engine monitoring.
`The airlines have historically been interested in
`performance monitoring. They ask, "Is the engine performance trend changing. and
`if so. what maintenance will we need to schedule?" The military. on the other
`hand. has been more interested in Line Replaceable Units. fault isolation and
`engine goIno—go decision-making using existing indication and control parameters.
`They ask "Is the engine available and will it complete a mission; if not. what do
`we have to do to fix it?"
`
`BOEING
`Ex. 1019
`
`

`
`22-10
`
`Today's monitoring systems have improved to the point where both groups are
`finding them cost—efficient and effective. As with many good things. success does
`not come without a major contribution from the users themselves.
`Today GE's custo-
`mers know what they want and why they want it. They are prepared to dedicate
`personnel who will understand. maintain. and utilize the system.
`
`In the future, analysis of on—wing modular performance promises to better
`manage engine maintenance.
`Some organizations envision the time when shop
`refurbishment workscopes might be largely defined prior to engine removal based on
`the assessment of modular performance changes. This would be far more efficient
`than the "once-we-get~it-apart-we‘ll-know-what-we- have-to-do“ method of engine
`analysis.
`Future airline plans might include the reduction or avoidance of test
`cell acceptance runs, refined cycle counting, APU health monitoring and improved
`integrated aircraft performance monitoring.
`
`The success of the A3l0iCF6-a0A3 GEM system has led to expansion of the
`monitoring capabilities to other applications. Universal GEM includes monitoring
`capabilities for the CF6-80C2, CF6-50. CFM56-3 and CFM56—5 in addition to the
`CF6—80A3.
`It provides a single monitoring system to use with all
`the CF6 and CFMI
`engine models. Refinement of the monitoring software continues based on airline
`operational experience. Use of GEM has been restricted to a limited but expanding
`number of airlines during this development period. At the beginning of 1988, GEM
`is operational at Air Frame. KLM, Lufthansa and SAS with efforts underway to
`install
`the system at Air Inter, Air Portugal
`(TAP). Quantas and Thai International
`later in the year.
`'
`
`Engine monitoring systems are coming of age. Recent advances have included:
`
`0
`
`0
`
`0
`
`Development of miniaturized electronics which can exist in a harsh
`environment.
`
`Introduction of digital controls on an increasing number of engines such as
`the CFMS6-5 and CF6-80C2. Digital controls reduce the need for unique
`monitoring instrumentation, provide highly accurate. reliable digital data
`and perform improved fault isolation.
`
`Development of software analysis techniques and availability of computer
`facilities to guide troubleshooting. maintenance.
`logistic support and
`planning.
`
`Military and commercial philosophies will come together in the next generation
`of advanced engines which will
`incorporate performance onitoring. modular health
`analysis. Line Replaceable Unit fault isolation. vibration monitoring,
`fan trim
`balance and control system programs.
`Such systems can reduce ground support. make
`the engine easier to support.
`track warranty provisions, control, and reduce the
`cost of ownership for all users.
`
`REFERENQES
`
`l. CF6-80 condition Monitoring - The Engine Manufacturer's Involvement in Data
`Acquisition and Analysis. AIAA-84-l4l2
`
`Dyson and Doel
`
`2.
`
`Introduction and”Application of the General Electric Turbine Engine Monitoring
`Software within KLM Royal Dutch Airlines. ASME-B7-GT-167
`
`Lucas and Paas
`
`3.
`
`Engine Condition Monitoring - Two System Perspectives.
`
`ATA E&M Forum. Oct. 1985
`
`Tykeson and Dienger
`
`BOBNG
`Ex.1019