Tutorial IEEE PHM SAFRAN AIRCRAFT ENGINES Dallas 2017
Marion Jedruszek, François Demaison, Jerome Lacaille, Josselin Coupard, Guillaume Bastard, Yacine Stouky Prognostics & Health Monitoring @ Safran Safran Aircraft Engines, 77550 Moissy-Cramayel, France
This document and the information therein are the property of Safran. They must not be copied or communicated to a third party without the prior written authorization of Safran SAFRAN AIRCRAFT ENGINES PHM / TUTORIAL CONTENTS
Global PHM System Architecture Operational realizations System perimeter PHM Systems on CFM56 & Silvercrest engine Engine dysfunction analysis Gaining in confidence in a PHM System Engine wear modes Predictive & Effective maintenance System architecture 1 2 3 4
Introduction & Context Embedding a PHM System Why PHM for Aircraft Engines ? Constraints on airborne systems Harsh environment & monitoring
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ABOUT US
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3 June 2017 / R& T 1 2 3 4 Q This document and the information therein are the property of Safran. They must not be copied or communicated to a third party without the prior written authorization of Safran About us
SAFRAN GROUP IN BRIEF 1/4
More than 70 successful 1 single-aisle commercial jet takes Ariane5 launches in a raw off every 2 seconds, powered by our engines
1 out of 3 helicopter Over 35,000 turbine engines sold power worlwide 17,300 nacelle transmissions, components in totaling over 850 service million flight-hours
More than 40,000 500km of electrical wiring on an landings a day using our Airbus A380 equipment
4 June 2017 / R& T 2 3 4 Q This document and the information therein are the property of Safran. They must not be copied or communicated to a third party without the prior written authorization of Safran About us OVERVIEW OF SAFRAN GROUP 2/4
SAFRAN AERO SAFRAN AIRCRAFT SAFRAN CERAMICS SAFRAN ELECTRICAL SAFRAN ELECTRONICS BOOSTERS ENGINES & POWER & DEFENSE
- Partner to major engine- - a world leader in aircraft - specialist in advanced - a world leader in aircraft - a global leader in aerospace makers engines ceramic materials electrical systems and defense electronics
SAFRAN HELICOPTER SAFRAN IDENTITY SAFRAN LANDING SAFRAN NACELLES SAFRAN TRANSMISSION ENGINES & SECURITY SYSTEM SYSTEMS
- The power transmission - The world leader in aircraft - A world leader in aircraft - The world leader in - Security solutions for people specialist landing and braking systems helicopter turbine engines around the world engine nacelles
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SAFRAN AIRCRAFT ENGINES 3/4 LEAP -15% of FUEL 99,9% of reliability CONSUMPTION rate versus today’s Over 1h30 average flight engines leg SAM146
15,000 -50% of NOX 500,000 flight employees emissions versus SAM146 hours with SSJ100 CAEPI6 standards Engines -15% of CO2 emissions versus for commercial and 35 todays engines military facilities aircrafts worldwide LEAP* M53 More than 30,000 produced since the outset
Recognized for its unrivaled reliability M88 and low operating and maintenance Maintenance, Electric costs propulsion Repair and systems for The benchmark
powerplant in the CFM56 Overhaul (MRO) satellites and PPS & TMA single-aisle services space commercial jet vehicles Plasmic propulsion CFM56* market Partners with GE in CFM International since 1974: design and production of the CFM56 and LEAP engines 6 June 2017 / R& T 1 2 3 4 Q This document and the information therein are the property of Safran. They must not be copied or communicated to a third party without the prior written authorization of Safran About us CFM International 4/4
A 50/50 joint company between GE(U.S.A) and Safran Aircraft Engines (France), we develop, produce and sell the new advanced-technology LEAP engine and the world’s best-selling CFM56 engine since 1974
2009-2011 – LEAP selected 30,000 CFM56 by three major aircraft manufacturers: Airbus engines delivered (as of December 31, 2016) (LEAP-1A), Boeing (LEAP- 1B) and COMAC (LEAP-1C)
74% of the global LEAP: more than market for engines 12,200 engine powering single-aisle orders and commercial jets commitments at January 31, 2017
7 June 2017 / R& T 1 2 3 4 Q This document and the information therein are the property of Safran. They must not be copied or communicated to a third party without the prior written authorization of Safran Chapter1 1/20
Global PHM System Architecture Operational realizations System perimeter PHM Systems on CFM56 & Silvercrest engine Introduction Engine dysfunction analysis Gaining in confidence in a PHM System Engine wear modes Predictive & Effective maintenance & Context System architecture
Why PHM for Aircraft Engines ? 2 3 4
Embedding a PHM System Constraints on airborne systems Harsh environment & monitoring
8 June 2017 / R& T 1 2 3 4 Q This document and the information therein are the property of Safran. They must not be copied or communicated to a third party without the prior written authorization of Safran Chapter 1 CHAPTER 1 ON “WHY PHM IN AIRCRAFT ENGINES ?” CONTENTS 2/20
Part 2 : Engines operation Usage & Operational life 1
Part 1 : Aircraft Engines Part 3 : Engines Maintenance Engines : from design to production Maintenance type and Engine maintenance owner
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Part 2 : Engines operation Usage & Operational life Aircraft Engines: Short introduction from design to production
Part 3 : Engines Maintenance Maintenance type and Engine maintenance owner
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Can be more expensive Engine are Over than an designed with $1,5 billion aircraft total trade based Development development on Specific costs cost around 25% Fuel of the aircraft’s Support for engine for a 15- Consumption, price when sold year rate per flight hours with Thrust, Fan Over Catalog price for 20 years Aircraft engines are an essential part of the leap-1A is an airline of 20 leaps costs Diameter and product cycles aircraft as fuel burn is one of the main key $13,9 $3,000 per engine Direct span driver for an airline millions per day Maintenance costs with EASA and . FAA have respect to Turbofan aircraft engines specific range consumes oil with a ratio defined Specific regulations / Flight legs of 0,1 liter per hour materials during cruise phase with respect to (Ceramic the conception, matrix the Today’s engines such as composites , manufacturing LEAP provide 15% fuel 3D Woven and the burn difference with older Carbon maintenance of an engine. Specific test means may be developed with a generation of engines. Fibers) new engine
11 June 2017 / R& T 1/3 2 3 4 Q This document and the information therein are the property of Safran. They must not be copied or communicated to a third party without the prior written authorization of Safran Chapter 1 Part 1 Technical layout of an engine (Leap-1A) 5/20
Take-off Thrust : Fan Bypass Ratio Leap-1A23 : 106.80 kN, Size : 78’’ or 198cm between veins Leap-1A30 143.05 kN (or 18 Composites Fan blades BPR: 11:1 32,160 lbf) Max RPM ~ 4,000
2 stages HP Turbine Length: 3.328 m With 3D aero and advanced Max Width : ~2.5m cooling Max Height 2.37 m Max RPM : ~20,000
Weight : 2,990-3,153 kg / 6,592-6,951 lbs 7 stages LP 2 Rotors : 1 high pressure, Lean Turbine annular 1 low pressure combustor
Fan Case: Direct Drive engine Active Composite & Noise 3 Stages Low Pressure clearance 10 stages High Pressure Compressor control with t treatment Compressor or Booster with Pressure ratio 22:1 HPTACC and FADEC is on fan case VBV Doors LPTACC actuators
12 June 2017 / R& T 1/3 2 3 4 Q This document and the information therein are the property of Safran. They must not be copied or communicated to a third party without the prior written authorization of Safran Chapter 1 Part 1 Characteristics of a PHM System 6/20
PHM – Prognostics & Health Monitoring
Monitor and forecast the health status of an engine.
• Integration from the Start of the On Board Development Cycle. From the beginning
Data • The Challenge of the Automatic and Adaptable Data Transmission and Automatic & Adaptable Transmission connection.
• A new PHM Standard for an Optimal Agile, Based on Standard On Ground Workflow. And Web accessible
13 June 2017 / R& T 1/3 2 3 4 Q This document and the information therein are the property of Safran. They must not be copied or communicated to a third party without the prior written authorization of Safran Chapter 1 Part 1 PHM Life Cycle 7/20 At SAFRAN Aircraft Engines PHM is about monitoring and predicting the health of an engine, using operational data to enable our clients to have a continuity of service while keeping a maintainability of the engine that is cost-oriented and optimal.
Development of PHM System Signal Capture & & data base detection process on engine
PHM System PHM System Operational Phase OSA-CBM approach: Design Phase • DM – data PHM manipulation models • SD – state detection • HA – health estimation • PA - RUL & prognostics
Analysis are done to Needs collection provide maintenance & Risk analysis Accurate trouble-shooting Engine Failures & support to build CNR of PHM System and maintenance support Degradations analysis advice
14 June 2017 / R& T 1/3 2 3 4 Q This document and the information therein are the property of Safran. They must not be copied or communicated to a third party without the prior written authorization of Safran Chapter 1 Part 1 Engine design : Example with TP400-D6, the engine of the A400M aircraft 8/20
2008: A400M 1st Flight EASA restricted Certification type 1980 1990 2000 2010 1982 FLA timeline 1989 A400M timeline 2002 2009 2013
Engine timeline RFI RFI RFP 1999 2002 2003 2004 2005 2006 2007 2008 2009 2010 2016 1980 1990 2000 Propeller Engine 1st st certification Definition TPI M138 engine Europrop TP400 1st engine 1 Ground Test Engine change down selected selected Test without With propeller Flight Clearance propeller CDR Engine certification Definition of engine fixed for production
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“I am third the weight and twice the strength of Ni-base alloy metals and have 20 per cent greater temperature capability? What material am I? The answer was ceramics matrix composites. Ceramic matrix composites (CMCs) are a subgroup of composite materials. They consist of ceramic fibres embedded in a ceramic matrix, thus forming a ceramic fiber reinforced ceramic..
Production is now facing different high technics materials to include into the engine. Estimating the quality of the production is going more on more to rely on big data and SHM functions.
Monitoring of the production and put the data at the same place than the operational data is one of the challenge of the data lake.
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Aircraft Engines Usage & 1 Operational life
Part 1 : Aircraft Engines Part 3 : Engines Maintenance Engines : from design to Maintenance type and Engine production maintenance owner
17 June 2017 / R& T 2/3 2 3 4 Q This document and the information therein are the property of Safran. They must not be copied or communicated to a third party without the prior written authorization of Safran Chapter 1 Part 2 Engine operation about thrust and its effect 11/20 Effective Thrust
Consumes oil Pilot’s commands Degrade its LLP* Aircraft
demand Engine Thrust Thrust Lever
Electrical Power demand A/C power A/C events: Engine events : • Air Turn Back Fuel • Delay & • LOTC & LOPC Cancellation (Loss of Thrust • Aborted Tack off (power) Control) Eng start / Fuel cut off LLP* = life Provide fuel limited parts
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FAA & EASA regulations define certification processes (FAA/EASA e-regulation Part 21, Airops, Part M, Part 145…) for design, manufacturing of the engines and the aircraft. Also, the exploitation and the continuity of airworthiness are specific regulation chapter.
Design Production Exploitation Air Worthiness Part 21 Part 21 AIROPS Subpart G PART M Subpart J Performing Maintenance Part 145
Engine OEM Airline
Airlines are responsible of the continuity of airworthiness as such they decide what maintenance action to take. Service are provided by engine OEM that are for guarantee or guiding decision when an “aircraft on ground” event occurs.
19 June 2017 / R& T 2/3 2 3 4 Q This document and the information therein are the property of Safran. They must not be copied or communicated to a third party without the prior written authorization of Safran Chapter 1 Part 2 Aircraft Engines Monitoring 13/20 Engine Engine is monitored throughout development phase as well as during all its life. PHM is about monitoring only during the “in service life”. In service
Reception During development Operational Inspections Development of an engine goes from 3 to 10 years and test Inspections are done engine’s certification toward EASA or FAA requires evidences. life on airlines initiative. Proof could be delivered through engine tests.
As such the conduct of the test plan can be hazardous as some test requires some specific meteo conditions (such as maintenance icing) Monitoring is done at each test trials often in a manual way by Maintenance are done in shops, may the engineers as they need to know if the expected behavior is be outside OEM perimeter. the one measured. That way first maturation of the fault logics as well as flight specific health assessment is done.
Monitoring logics are focused on : - Engine main functions & Engine critical pieces 20 June 2017 / R& T 2/3 2 3 4 Q This document and the information therein are the property of Safran. They must not be copied or communicated to a third party without the prior written authorization of Safran Chapter 1 Part 3 CHAPTER 1 CONTENTS 14/20
Part 2 : Engines operation Usage & Operational life Engines Maintenance Maintenance types and 1 2 Engine maintenance actors
Part 1 : Aircraft Engines Engines : from design to production
21 June 2017 / R& T 3/3 2 3 4 Q This document and the information therein are the property of Safran. They must not be copied or communicated to a third party without the prior written authorization of Safran Chapter 1 Part 3 Engine maintenance 15/20 Typical airline organisation
OEM CNR Service bulletin
Safran Aircraft Engines PSE Maintenance is shared between the airlines (or aircraft operator), and the OEM.
The responsible toward the authority (for example FAA) is the CAMO (Continuing Airworthiness Management Organisation) that organize the maintenance. CAMO can have at most only 2 subcontractors (for the whole aircraft) with respect of their activities according to the Appendix II 1321/2014 AMC M.A.711(a)(3)
OEM can provide maintenance recommendations on demand or on service request but only those made by the CAMO are accountable for in term of responsibility or engaging orders.. 22 June 2017 / R& T 3/3 2 3 4 Q This document and the information therein are the property of Safran. They must not be copied or communicated to a third party without the prior written authorization of Safran Chapter 1 Part 3 OEM is a supportive 16/20 Engine maintenance OEM CNR partner for Maintenance plan Operational maintenance on its Events product. Service bulletin Inspection Inspection results Workscope Maintenance Workscope Engine inspection On-Wing Maintenance Engine overhaul
On site Maintenance Engine is controlled through visual Oil refilling, data downloading, inspection (borescope), or NDT on-wing troubleshooting, LRU tests. replacing are common events done Shop by the airline. Engine maintenance may need to Engines may need to be overhauled Note that technician are certified remove the engine from the aircraft. to proceed to the inspection of zone with respect to a set of maintenance Operation can be done either on-site not reachable on wings. operations only and not all possible. (near aircraft deposit) or in specialized shop. Sometimes engine washing is need An engine can be leased in the to be able to inspect. meantime.
23 June 2017 / R& T 3/3 2 3 4 Q This document and the information therein are the property of Safran. They must not be copied or communicated to a third party without the prior written authorization of Safran Chapter 1 Part 3 Maintenance type 17/20 • The different type of maintenance are as followed Hard Time Maintenance Condition Based Maintenance Probability of failure & Maintenance Engine installation on Aircraft Restoration zone design condition Precision Monitoring Tests CBM condition Predictive Advisory Maintenance
Failure Rate Failure information Asset condition Asset Failure margin condition TSN Corrective Maintenance Time to failure “Run-To-Failure” Time since TSN Hard Time Maintenance New Time since New
Hard Time Maintenance: Maintenance is done at fixed intervals (time or cycles)
Maintenance on Condition : Maintenance is performed when condition or statement are required. For example when occurs a FOD (foreign Object Damage) like hitting a bird a maintenance operation can be done
24 June 2017 / R& T 3/3 2 3 4 Q This document and the information therein are the property of Safran. They must not be copied or communicated to a third party without the prior written authorization of Safran Chapter 1 Part 3 18/20 Engine maintenance: Benefits of PHM today at Safran
Engine PHM Benefits
Airline OEM
- Be confident on the engine ability to - Better know the condition of the engine provide thrust on demand during a work day or more and how it’s evolving. - Have a visibility on the maintenance - Better know the client needs based on operation and early warning to optimize engine feedback. operation - Provide better feedback to design team - Reduce engine-failure trigged events. about conception margin.
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After this point, two threads will be used in order to have consistent examples on PHM at Safran. The two selected thread are here under :
- Engine take-off capability
Aircraft engine performance is about to lift off the aircraft. Monitoring this performance is required by PART M certification on a regular basis.
A key parameter to follow is the exhaust gas temperature during the maximum constraint point (generaly the takeoff). In fact, as the engine ages, it lost its efficiency and for the same takeoff its temperature needs to be higher.
- Engine Range follow-up
Aircraft engines have their own consumables. The one that has the shortest cycle is the oil that is used to lubricate its gears and bearings (interface between rotating and fixed parts).
26 June 2017 / R& T 3/3 2 3 4 Q This document and the information therein are the property of Safran. They must not be copied or communicated to a third party without the prior written authorization of Safran Chapter 1 Part 3 ETOPS : A regulation need for Monitoring 20/20
Extended Range Operations with Two-Engined Aeroplanes ETOPS Certification and Operation (AMC 20-6)
consumption
Oil
margin N2 & EGT EGT & N2
For Leap, oil consumption monitoring will be automatized
27 June 2017 / R& T 3/3 2 3 4 Q This document and the information therein are the property of Safran. They must not be copied or communicated to a third party without the prior written authorization of Safran Chapter 2 Chapter2 1/39 Operational realizations PHM Systems on CFM56 & Silvercrest engine Gaining in confidence in a PHM System Predictive & Effective maintenance
GLOBAL PHM SYSTEM ARCHITECTURE
System perimeter Engine dysfunction 4 analysis 1 Engine wear mode System architecture 3
Embedding a PHM System Introduction & Context Constraints on airborne systems Why PHM for Aircraft Engines ? Harsh environment & monitoring
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CHAPTER 2 CONTENTS 2/39
What to monitor in an aircraft engine ? PHM System Conception Failure Mode & Operational Hazard analysis PHM System Architecture Engine degradation & wear mode analysis Operational procedures specification 1 2 3 4 5
Conception process Engine Health Monitoring Functions Conception PHM System Industrialization System engineering approach PHM System Function selection & conception System Design Engine Failure Risk Analysis KPI of PHM System Knowledge data base update
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What to monitor in an aircraft engine ? PHM System Conception Failure Mode & Operational Hazard analysis PHM System Architecture Conceptual Engine degradation & wear mode analysis Operational procedures specification Phase System engineering Engine 2 3 4 5 operational event Risk Analysis Engine Health Monitoring Functions Conception PHM System PHM System Function selection & conception Industrialization System Design KPI of PHM System Knowledge data base update
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Monitoring is done mainly to reduce opeartional events Example of CFM56-5B VBV system detection such as D&C, ATO, IFSD. • @Cruise flight phase, core parameters increasing is related to air Trend leakage issue
N2 Core speed deviation
Gradual deterioration EGT deviation Gradual deterioration
Discrete event Trended Parameter Trended • ~3 flights detection leadtime • Customer Notification Report is issued as Aborted Take-Off can TSN be avoided Time since New CFM56 figures 8000+ engines monitored in Safran Aircraft Engines zone 2 snapshots per flight, 4 analytics ~10 CNR types per engine type 3000+ alarms per month
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Air Inlet
Engine with Nacelle Bare Engine Turbomachine
A Turbojet is mainly composed of a :
Due to dilatation some clearance are introduce, but with the wearness of the engine, its performance Fan Module Booster & High Combustion Turbine degrade. Pressure Compressor Chambers 400°C 1200°C 1800°C
A degradation on all the veins will be traduce by a higher Exhaust Nozzle EGT (exhaust Gaz temperature) as more power is required Gas to reach the takeoff velocity. 32 June 2017 / R& T 1 1/5 3 4 Q This document and the information therein are the property of Safran. They must not be copied or communicated to a third party without the prior written authorization of Safran Chapter 2 Part 1 Context on monitoring Aircraft Engines : Lubrification system 6/39
Main Particularity of the lubrification system Pump on an aircraft Anti-Leak SACOC engine is that it’s Valve Bypass valve Main Fuel Oil Heat an open circuit that Exchanger DeltaP relases oil with a deaerator sensors target consumption
Engine Engine about 0.1 l/h on a cruise with a Oil modern engine
tank oil B C level
Filter Sump A
deoiler
Oil cartridge Sump AGB
Oil Debris monitoring Magnetic Chips Detector bars
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Machinery Information Management Open System Alliance (MIMOSA) OSA-CBM (Open System Architecture for Condition-Based Maintenance) V3.2.1
ISO STANDARDS ISO 13374-1 Condition Monitoring and diagnostics of machines –Data processing, communication and presentation –Part 1: General guidelines (equivalent as OSA-CBM) ISO 13374-2 Condition monitoring and diagnostics of machines –Data processing, communication and presentation –Part 2: Data processing
IEEE IEEE P1856 Standard Framework for Prognostics and Health Management of Electronic Systems
SAE HM-1 Integrated Vehicle Health Management Committee ARP4754-A System design process ARP6275 Determination of Cost Benefits from Implementing an Integrated Vehicle Health Management System (IVHM) AS4831A Software Interfaces for Ground-Based Monitoring Systems ARP6803 IVHM Cornerstone Document (Draft) ARP 6883 Requirements of an IVHM System (Draft) ARP6407 Guideline for the Design of an IVHM System (Draft)
34 June 2017 / R& T 1 1/5 3 4 Q This document and the information therein are the property of Safran. They must not be copied or communicated to a third party without the prior written authorization of Safran Chapter 2 Part 1 System engineering approach: Stakeholders of PHM Systems 8/39
Who is interacting with the PHM System ? 3rd party PHM External stakeholders
Airlines (including Aircraft mainenance) manufacturer Nacelle manufacturer Airports Design Operational life Shops life
Trouble warranty Shooting Supply Engine Design Chain Team PSE
Internal stakeholders
>>the different stake holder implies possibility to have different perception of the needs clarification of needs and priority between express need is important
35 June 2017 / R& T 1 1/5 3 4 Q This document and the information therein are the property of Safran. They must not be copied or communicated to a third party without the prior written authorization of Safran Chapter 2 Part 1 Monitoring perimeter : engine or engine zone (IPPS) ? 9/39 Engine Owned by Engine OEM (like IPPS: integrated power plant system Safran Aircraft Engines) Jet engine: A jet engine is Can be split in more than one a reaction engine discharging a fast- actor moving jet that generates thrust by jet propulsion. Engine OEM Nacelle Airlines Owned by Nacelle OEM Aircraft operators (airlines) are in charge of the Include mechanical parts continuity of airworthiness of the aircraft and its engine. Aircraft Nacelle OEM All the data produced by engine, aircraft or nacelle are the propriety of the airlines.
Note that due to regulation, it is classified that 8 of Aircraft the 80 possible aircraft equipments (ATA) of a large 8 ATA are on the IPPS zone aircraft are located on the IPPS zone. Such as : Bleed Air system (BAS), Fuel systems, hydraulic power, electrical power …
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Once the needs are collected an Business Global PHM analysis is done on the perimeter to Needs system address an analysis is done to segment the system into functions. Global PHM Global PHM System reqs function Ground Ground PHM Needs are then translated into Reqs Function requirements and requirement are Embedded Embedded Req PHM function allocated on an engine embedded product and to a ground product. Traceability Algorithm Ground software Requirements are then used for Verification implementing software solutions Conformity
Embedded If required verification is done HW & SW independently and integration is done very late in the project. Some PHM system design’s assumptions are verified more than 3 years after the entry in service of the engine.
37 June 2017 / R& T 1 1/5 3 4 Q This document and the information therein are the property of Safran. They must not be copied or communicated to a third party without the prior written authorization of Safran Chapter 2 Part 1 Engine failure leading to shop visits 11/39 In term of business of airlines, hardware and NOEC shouldn’t lead to an engine overhaul. PHM should help to have detected it before leading to a damage that needs heavy maintenance.
Legend
Hardware : Equipment faults leak
LLP : Life limit part with life on engine exhausted fluid NOEC : No Engine Cause found dispatch
Other : other causes expiration
Engine
Engine Engine Vibration Engine
38 June 2017 / R& T 1 1/5 3 4 Q This document and the information therein are the property of Safran. They must not be copied or communicated to a third party without the prior written authorization of Safran Chapter 2 Part 2 CHAPTER 2 CONTENTS 12/39
What to monitor in PHM System Conception PHM System Architecture an aircraft engine ? Operational procedures specification Failure Mode & Operational Hazard analysis 1 Engine 3 4 5 degradation & wear mode analysis Engine Health Monitoring Functions Conception PHM System PHM System Function selection & conception Industrialization Conceptual Phase System Design System engineering approach KPI of PHM System Engine Failure Risk Analysis Knowledge data base update
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OEM classify the piece of the engines with respect of their criticality and the damage tolerance.
It standard to speak about damage classifications for critical parts.
N1 are pieces that are represented with red here, and the engine must function with only a tolerance (2mm crack) on these pieces and acceptable damages are below that tolerance.
LLP parts design all the pieces that are to be changed at fixed cycles or engines usage time.
For engine design, typical missions scenarios are used based on airframer assumptions. During operational life, the number of cycle are to be more followed-up.
40 June 2017 / R& T 1 2/5 3 4 Q This document and the information therein are the property of Safran. They must not be copied or communicated to a third party without the prior written authorization of Safran Chapter 2 Part 2 Engine Failure Modes & Operational Hazards analysis 14/39
Exhaust Gas Temperature Full Engine N2 Fuel flow is monitored
Combustion Fan Compressor Turbine chambers
Fan degradation is Erosion, and dust No trend on fuel mainly caused by can stick to the chamber only events such as compressor cracks or fuel Blades (FOD). elements. system Erosion, corrosion Note: Event such leads to degradation monitoring as large bird strike compressor leads to turbine lead to inspection. performance drop performance drop Clearance Damage estimation based on usage leads to turbine performance drop
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Corrosion Environment Fluid Contamination Erosion
FOD
Usage
42 June 2017 / R& T 1 2/5 3 4 Q This document and the information therein are the property of Safran. They must not be copied or communicated to a third party without the prior written authorization of Safran Chapter 2 Part 2 Engine wear modes analysis: using EGT indicators 16/39
Normalization of trend parameters Based on Online Normalization Algorithm for Engine Turbofan Monitoring, January 2014, J. Lacaille.
Dust ingestion Engine Storage Borescope Water wash EGT inspection High dispertion Leads to Bad storage compressor degrades the performance engine. Normalized EGT drop Compressor restoration Objective : to extract a reduced number of
EGT dimensions on which the data may be explained. The reduction of EGT dimension enables the computation of meaningful
distances (i.e. and allows Normalized cycles the computation of Engine storage scores.) Opportunity of PHM: A pre-diagnostics on maintenance to make the proper maintenance operation at the less impacting time for the company
43 June 2017 / R& T 1 2/5 3 4 Q This document and the information therein are the property of Safran. They must not be copied or communicated to a third party without the prior written authorization of Safran Chapter 2 Part 2 Engine Failure Modes & Operational Hazards analysis 17/39
Lubrification circuit SACOC: FOHE: Oil : Fatigue & FOD Fluid contamination Oil with debris Pumps (main & Leading to Leading to leaks or bubble scavenge): performance drop Particle release
Bearing & Sump : particles release in oil circuit Deoiler: Leaks in sump: oil consumption increased More Oil ejected with air as performance decrease 44 June 2017 / R& T 1 2/5 3 4 Q This document and the information therein are the property of Safran. They must not be copied or communicated to a third party without the prior written authorization of Safran Chapter 2 Part 2 Engine wear modes in real 18/39
Oil leak impact on thrust reverser doors Oil tube is damaged (fan frame)
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Environment
Corrosion Vibrations
Particules Thermal released env. Usage
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What to monitor in an aircraft engine ? Failure Mode & Operational Hazard analysis Engine degradation & wear mode analysis PHM System Conception PHM System Architecture Engine Health Monitoring Operational procedures specification Functions Conception PHM system functions 1 2 conception & 4 5 selection
Conceptual Phase PHM System System engineering approach Industrialization Engine Failure Risk Analysis System Design KPI of PHM System Knowledge data base update
47 June 2017 / R& T 1 3/5 3 4 Q This document and the information therein are the property of Safran. They must not be copied or communicated to a third party without the prior written authorization of Safran Chapter 2 Part 3 How to assess the most prioritary items to monitoring ? 21/39 Needs priorization Functional Architecture Technical needs are collected to define Regrouping the needs into logicial functions is a step the system. However clarification is that rationalize the project content. Functional blocs needed as well as some priorization. are identified to split the different needs and major However as some needs may be function into component that can be requirements for different to address the same sub-systems. Blocs mapping may also be known as it perimeter, a priorization must be done can be linked to a referential of tech blocs. like a negociation between different stake holders. A description of the project can be done in SysML to QFD method for example help clarify the scenarios and the function needs. Detailed design Solutions selections Preliminary design is used for system Components Value assessment. To check its design Cost on value approach feasibility Design efforts are taken into Interface design account as well as costs (Non reccurent & reccurent). Architecture conception Effort (with risks) 48 June 2017 / R& T 1 3/5 3 4 Q This document and the information therein are the property of Safran. They must not be copied or communicated to a third party without the prior written authorization of Safran Chapter 2 Part 3 OSA-CBM 22/39
Prognostics: Can be different corresponding to different health status: - Confirmed fault - Early warning - Early detection
Definitions
Trend Deviation: In a noisy signal a trend estimation is made with a statistical technique to Early Warning system: aid interpretation of data. Deviation spots an inflexion in the signal. An early warning system can be implemented as a chain of information that comprises sensors and event detection decision Anomaly detection: support and message broker to forecast any signal anomaly detection (also outlier detection) is the identification of items, events or observations which do not conform to an expected pattern or Health status: other items in a dataset. Indicator that reflect the asset / component condition
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TRL/MRL/DRL and gain/effort matrix
Development effort is one of the driver to have the deployment of a new technology different scales are used to assess the development effort that are to be done. Target (new engine) EIS RFP FETT
FETT EIS RFP Data readiness level (data driven) Maturity readiness level (CMMI rule)
Technology readiness level 50 June 2017(model / R& T based) 1 3/5 3 4 Q This document and the information therein are the property of Safran. They must not be copied or communicated to a third party without the prior written authorization of Safran Chapter 2 Part 3 Strategies on building PHM functions 24/39
Model based vs Data Driven functions Harvest Data KPI of model Listen share physics integration
modeling Optimize Analyze Analytics Data
simulation engage discover Activate Test on Analytics devices
Pro: Centered on product integration (Embedded or ground). Pro: Optimize Data usage – adapted on ground. Validation Costs Development costs Con: Physics must be known Con: Dependent on data sources
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Signal/Noise ratio anomaly Trend speed
1..k
Trend Confirmation time speed
Output indicator
precision robustness 1..z 0..y
Endogene inputs Exogenes inputs
influence
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Simplification issues
Because detection may likely to trig an huge amount of variables an important point is about function segmentation and variable reduction. Robustness and algorithm maturity will depend on the data size, and if we take assumption on the KPI will need much more data to be assessed. It seems to take and exponential law to provide the right amount of points.
Usage of for example a LASSO criterion such as described in the article « Sudden Change detection in turbofan engine behaviour » J. Lacaille 2011 can provide interesting information. A LARS (Least Angle Regression) algorithm Effron 2004, can be used to estimate all the solution of the LASSO criterion for all possble values of C with respect with the KPI error that is to be mimimized.
53 June 2017 / R& T This document and the information therein are the property of Safran. They must not be copied or communicated to a third party without the prior written authorization of Safran Chapter 2 Part 3 PHM Function design – EGT Trending 27/39 DA DM SD HA PA objectives Data saved EGT Trend EGT EGT (max EGT) @ISA25 Events
Temperature for each module Trend on EGT Pressure Model Anomaly for each module on EGT detection Estimation may based on model be realized output
Engine condition need calibration With experts vote All available data
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Oil dilatation law EOL/EOT
Resolution issues
All available data Anomaly detection
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What to monitor in an aircraft engine ? Failure Mode & Operational Hazard analysis Engine degradation & wear mode analysis
PHM System Conception
PHM System Architecture 1 2 3 Operational procedures 5 specification
Conceptual Phase Engine Health Monitoring PHM System System engineering approach Functions Conception Industrialization Engine Failure Risk Analysis PHM System Function selection & System Design conception KPI of PHM System Knowledge data base update
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PHM System : Black Box
FADEC Data and aircraft Data PHM System Indicators (Global) Fleet Manager Data Base CNR
Depending on the maturity of a product there may be in a PHM System :
Raw Indicators only, Visualizations, Business Indicators, Engine level condition indicators, Customer Preformatted Recommendation on the Ouptput size, and FADEC or other systems for the INPUT side.
Humans have to intervene before the end of the system. Architecture conception works on defining subsystem from main system
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Sense Transfer • Snapshot acquisition • Specific Raw data @ takeoff • Max EGT computed • Environment severity • Snapshot enriched • Information sent on estimation (sand, ice) with previous and flight basis on ground following data • Transfer engine • Sensor error to be configuration estimated information Data Acquire Acquisition
• Normalized EGT SD • Signature PA • CNR made in case with defined classification on of event that will be environment • Anomaly tracking EGT trend (dust • Prognostic on EGT confirmed by condition with model (that ingestion, water operator contain aging wash…) information) DM HA AG
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Sense Transfer • Snapshot acquisition • Specific Raw data @ beginning and end • Oil level difference in of flight • Sensor error to be a flight and flight • Information sent on • Environment severity estimated (oil level, oil duration flight basis on ground estimation tank temperature) • Transfer engine (temperature) configuration information Data Acquire Acquisition
• Normalized oil SD • Analyse done PA • CNR made in case level difference manually on of event that will be with defined • Anomaly tracking signature • Manual confirmed by environment with model prognostics on oil operator condition consumption trending DM HA AG
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60 June 2017 / R& T This document and the information therein are the property of Safran. They must not be copied or communicated to a third party without the prior written authorization of Safran Chapter 2 Part 4 PHM System architecture 34/39
Architecture is mainly made on choices. Trade are conception choices that defines the system and its performance. This slide and the next ones are about possible trades that can be made during a conception.
Design option1 : aircraft integrated architecture or not Today : Independant engines Tomorrow : Aircraft integrated ? Engine Embedded system are constraints in term of CPU and memory.
One counter measure would be to host computation ECU into the aircraft
Engine PHM system is autonomous The cost is more dependancy mainly use aircraft to transmit information on the ground station. toward aircraft manufacturer
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Design option 2 : full embedded or full ground ?
Full Embedded PHM System Full Ground PHM System Objective: be able to update analytics very quickly Objective: be fully autonomous without satellite and have data driven models running on fleets. link to make PHM indicators Gain : optimization of model, new algorithm Gain : no specific infrastructure on ground for (machine learning) data hosting, easy scalability toward fleet Deployment. Cons: Data to be put on ground More difficult to know the sensor to add in a new Cons: Accessibility and software update. project..
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What to monitor in an aircraft engine ? PHM System Conception Failure Mode & Operational Hazard analysis PHM System Architecture Engine degradation & wear mode analysis Operational procedures specification
Operational life preparation
System Design KPI of PHM System 1 2 3 4 Knowledge data base update
Conceptual Phase Engine Health Monitoring System engineering approach Functions Conception Engine Failure Risk Analysis PHM System Function selection & conception
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System will be split into different components. PBS – Product Breakdown structure and DBS – Document Breakdown structure will help to understand better. 3
conception 6
Detailed 22
On ground 64 June 2017 / R& T On board This document and the information therein are the property of Safran. They must not be copied or communicated to a third party without the prior written authorization of Safran Chapter 2 Part 5 PHM System KPIs 38/39
KPI are issued on PFA and POD that can be modeled as alpha and beta here >>
Detection quality are juged through those KPI, however they need to be associated on events as all are not equaly seen by the customer.
First of all here is a brief description of airlines. In fact, IATA have define the Completion Rate indicator as such
CR = (scheduled flights – cancelliing + affretings)/scheduled flights
Performance is based on individual performances + machine availibility.
It exists : CR WATOG and CR Total
CR WATOG is World Airline Technical Operation Glossary : 1st technical problem is taken into account and not its consequences. CR Total : all events are taken into accounts.
Airlines are as such interested in the different performance with respect to different events that can occurs
@ aircraft level : Delay & Cancellation, Aborted Take-Off, Air Turn-Back
OEM are more interested to know on the engine side:
@engine level : LOTC/LOPC, Dispatch …
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Today : Data are provided by airlines to PSE Tomorrow : Data are sent automatically
Cloud Application & Services Certified Data : QAR, DAR, SAR Engineering data: CEOD, FFD, RWD Data Storage Contracts Contract management
Customer Support Center & PSE Client Notifications Operator Analytics Technical Guides & models AMM, FIM, FIP, HAZOP, … base of running & knowledge optimization Engine configuration & CDM Damage models, engine configuration information KPIs Quality factors
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1 EMBEDDING A PHM SYSTEM
Constraints on airborne systems Harsh environment & Introduction & Context monitoring Why PHM for Aircraft Engines ?
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Appropriate number of sensors « PHM Flight dedicated » Engine Measure High accuracy
Compute Basic processing No loss of usefull information No Constraint Real time transmission Transmit All data, whole flight
Ground Main challenge : deal with a huge amount of data station
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Re-use of regulation/monitoring Flight Environment, installation, Engine 2 Measure sensors Insufficient accuracy weight
Environment, H/W techno, Compute Complex processing 3 Loss of usefull information S/W development costs
Sporadic transmission (at the end of a Transmission techno, mission or less frequently) 1 Transmit Part of data, specific mission phases operational costs
Ground Main challenge : data recovery and improvement + deal station with a high amount of data
Embedded processing is driven by transmission capability on the one hand, and by the best re-use of existing sensors on the other
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Measurement Choice of Sensors Accuracy retrieval methods
Transmission
Aircraft to Ground Engine to Aircraft 2 3
Computation Hardware in Engine environment Computation optimization
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• Some engine characteristics
• 16 000 parts, 2 400 references, …30 sensors and thousands of parameters
• Phenomena to be monitored with dynamics up to several kHz D = 2m For a 2h flight, it represents several GB of data per engine
• More than 30 000 CFM56 engines produced
L = 3,3m • The aircraft stops at the airport gate for approximately 30min
Need for a bandwidth of several hundreds of KB/s
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Ideal World 3G / 4G / WiFi Radio + Satellite communications All data High volume of data Low volume of data Immediate On ground In flight
No recurring costs Low recurring costs High recurring costs
Strong upgradability : algorithms can Upgradability : more flexible system Upgradability : less flexible system easily be modified or new ones can be introduced
Basic embedded treatments Simple embedded treatments Complex embedded treatments
Real Time : data can be immediately Data sent on ground : airport must be Data sent in flight treated by the ground system properly equipped – aircraft must be powered up – limited time to download data
Ideal World : no implemented New technologies : not always accepted by Well known technologies technology yet the stakeholders
“Big Data” problematics on the “Big Data” problematics on the Ground Ground PHM System (Data Mining, PHM System (Data Mining, data storage) data storage) 72 June 2017 / R& T 1 2 33 4 Q This document and the information therein are the property of Safran. They must not be copied or communicated to a third party without the prior written authorization of Safran Chapter 3 Part 1 TRANSMISSION – From Aircraft to ground 3/6
Ideal World 3G / 4G / WiFi Radio + Satellite communications All data High volume of data Low volume of data Immediate On ground In flight
Pitfall : Pitfall : - too complex ground treatments (complexity and maintainability vs. efficiency) - too complex embedded treatments - not enough data transmitted Embedded / Ground Split Embedded Ground Embedded Ground Embedded Ground
Oil Consumption example: ■ Select and send only oil level + other ■ Select oil level data + influencial data; pre- Send all data ■ influencial data treatment on board and send compressed data ■ Selection of oil level + other influencial ■ All computation on ground data and all computation on ground ■ Further computation on ground
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Engine Legacy Aircraft (ex : A320 / B737 with CFM56 engine) System
• Development with no PHM Avionics • Frozen architecture and technologies • Avionic and embedded systems optimized to the needs
Re-use of current engine configuration with the least modifications
Example : addition of a link New engine programs (ex : Ideal World) High costs and weight increase exploitation costs increase • Development includes PHM service • Cable harness modification • A few decades of meters added a few kg • PHM taken into account in development • Computational units (both aircraft and engine) modification choices • Interfaces (pins) and hardware, software • Architecture and interfaces optimization
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Engine Legacy Aircraft (ex : A320 / B737 with CFM56 engine) System
• Development with no PHM Avionics • PHM is subject to the engine to aircraft existing link • ARINC (aircraft communication standard) allowing only low frequency data sending (~Hz)
More complex compression treatments
New engine programs (ex : New middle of market • Data treatment unit location : usually in the aircraft bay aircraft)
• No room left on the engine to add a PHM specific computational unit • Development includes PHM service
Less flexible because of more aircraft dependencies • Engine to aircraft link • Ethernet allowing high frequency data sending Limited evolutions (new functions, functions upgrading) (~MHz) possiblities • Data treatment unit location : usually on the engine • Eases re-use and more flexible 75 June 2017 / R& T 1 2 33 4 Q This document and the information therein are the property of Safran. They must not be copied or communicated to a third party without the prior written authorization of Safran Chapter 3 Part 1 TRANSMISSION - To sum up 6/6
Aircraft to ground Flight Engine 2 Measure • Bandwidth limited due to transmission technology
3 Compute Engine to Aircraft
• Different approach if legacy or new engine program
1 Transmit • Legacy : bandwidth is subject to the avionic already in place • New : bandwidth benefits from a more recent avionic
Ground station
Maximum transmission bandwidth known ? Which data to select and send ?
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Measurement
Choice of Sensors
Accuracy retrieval 1 methods 3
Transmission Aircraft to Ground Computation Engine to Aircraft Hardware in Engine environment Computation optimization
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Safety The Aircraft Engine is a major system : Safety is the priority !
Engine Trouble PHM control shooting It embeds different functions
Engine Wide operating It operates in a wide envelope environment envelope
Performances Equipment installation
Weight And has to fulfill many requirements « Green » engine Operating costs
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Some Sensor’s characteristics Engine Trouble PHM control shooting • Trueness (Accuracy, Precision, Resolution)
• Reliability, Robustness
• Sensitivity to influential non-measured Engine Wide operating parameters environment envelope • Operational domain
• Weight , Size, Shape Equipment installation Performances • Costs
Weight « Green » Re-Use of engine control sensors engine Operating costs
79 June 2017 / R& T 1 2 33 4 Q This document and the information therein are the property of Safran. They must not be copied or communicated to a third party without the prior written authorization of Safran Chapter 3 Part 2 MEASURE - Costs of an additional sensor – butterfly effect 3/14 Additional Weight Additional Fuel Burn Additional recurring costs
+ + (+ +…+ ) Signal processing unit Sensor (HW modification) Harness Conditioner
Additional development costs Additional maintenance/ in service support costs • Signal processing • Impacts on CPU usage, • Troubleshooting, maintenance operator formation, engine complexity computational load, calculation Time • Spare parts storage costs • Software modification + V&V • Transmission & bandwidth availability
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• Controls the engine : computes the commands and sends it to actuators Sensors Actuators • Engine protection functions : overspeed protection, fire protection…
• Communicates with the aircraft :
• Receives the aircraft data necessary to fulfill its role
• Send information to the aircraft (maintenance information, alerts…) PHM Engine Avionics & Controls Aircraft Systems
Opportunity for PHM
• PHM can use data computed by engine controls • Additional internal engine data and parameters But also associated limitations • Detection logics • Models : temperatures, pressures • Due to different needs between Engine Controls and PHM • Data validity status • Limited number of sensors • Accuracy, precision and/or acquisition frequency not always sufficient for PHM needs
81 June 2017 / R& T 1 2 33 4 Q This document and the information therein are the property of Safran. They must not be copied or communicated to a third party without the prior written authorization of Safran Chapter 3 Part 2 MEASURE - Engine controls: data status computation 5/14 Sensor redundancy
• 2 sensors measuring the same data independently Channel A Channel B • Data from each sensors are sent and processed independently Engine Controls
Range check A status is computed and a selection is performed Range check PHM can use the data status • As a current data status for PHM functions Cross check • For a specific monitoring function
Status computation & Data Selection
Selected value Data Status
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• Both Engine Controls and PHM need the oil level measure
Objective Needs on the sensor Engine Control - Detect low oil level (safety aspects) - Accuracy around extreme positions (full and - Detect if the tank is full or needs refill (binary) empty tank) - Very reliable PHM - Monitor the oil consumption and detect - Accuracy on the whole oil level range anomalies in the oil consumption
• Some other factors to take into account to choose a sensor • Installation constraints : oil tank design, oil sensor installation in the tank • Compact solutions • Sensor robustness to engine environment : strong thermic and mechanical stress • Avoid sensors with mechanical contacts • Sensor’s low sensitivity to influential parameters (temperature, vibrations…) • Possibility to implement a compensation (model…) Tank section • Costs
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푙 Rfault detection 푅 = 휌 resistor V 푆 푆 M 퐶 = 휖 AX 푑 ℎ 푆 = 2휋푟ℎ V mi • Continuous measurement n Sensitive to oil pollution 1 V 2 V 3 ref ou In case of fuel leakage t
• Discrete measurement variations Accuracy depending on the step width between the floats and 휖 the tank design Also other technologies, but too costly or too much impacted by the environmental constraints • Differential pressure sensor • Magnetostrictive sensors • Wave sensors
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Measurements come with numerous sources of errors
First step : Sources of error identification in the measurement of the monitored parameter
This step implies the sensor expert, the system specialist but also a lot of data visualization
Then : Sources of error classification Poor Accuracy Poor Precision
• Systematic errors impact on accuracy
• Random errors impact on precision
Action for each source of error is taken in order to Offset correction improve the trueness Filter
Process may be iterative with the trend design of the monitored parameter. Trend variation analysis may indicate if further improvement is necessary or not.
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type Objective : monitor oil consumption and detect of oil oil level measurement anomalies in oil consumption accuracy aircraft attitude influence
First step : Sources of error identification
oil flow influence oil temperature influence
86 June 2017 / R& T 1 2 33 4 Q This document and the information therein are the property of Safran. They must not be copied or communicated to a third party without the prior written authorization of Safran Chapter 3 Part 2 10/14 MEASURE - Aircraft attitude influence Oil tank: top view Lr Due to installation constraints, oil level sensor is not centered in oil tank. Lf lr lf This makes the measurement sensitive to aircraft movements (acceleration/deceleration, pitch/roll, …) because of oil surface inclination
First action is to select flight phase that minimize aircraft Oil level attitude: take off, climb, approach are excluded sensor Steady oil surface In flight attitude can be corrected but requires more parameters from the aircraft q and add extra complexity. h Oil surface with attitude Remaining attitudes are filtered. g az ay Oil tank: lateral view
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Reed switch Sources of errors are analyzed and classified in categories float
Lot of errors impact only accuracy and do not vary from one flight to another for same engine. They are cancelled when looking at trend variation. Tank section
Some errors are random and affect precision. Denoising will be necessary. Error sources impact
Some errors are dependent from external parameters: a model Floatability of the float in function of EOT f(Oil Temp) can be used to reduce it. Switch position tolerance accuracy Measurement is discrete here Sensor position / tank accuracy
Measurement resolution has a strong impact on precision Float weight tolerance accuracy
Rising and falling edges are preferred instants to save Hysteresis switch/magnet precision measurement. Measurement electric noise precision
88 June 2017 / R& T 1 2 33 4 Q This document and the information therein are the property of Safran. They must not be copied or communicated to a third party without the prior written authorization of Safran Chapter 3 Part 2 MEASURE - Oil temperature influence 12/14
Oil temperature has primary effect on oil level (dilatation + gulping)
Oils temperature follow a repeatable behavior Level
during taxi out when engine is heating. Oil
A model is built and used on ground
Oil Temperature Model is fitted with least square error reduction. This offers several advantages: Decision to record only rising edges on board > It is possible to estimate the oil level at a temperature reference level in order to be comparable from flight to flight > This reduces random errors has well as oil level quantization error.
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Not all errors can be completely cancelled type for several reasons: of oil oil level measurement > Accuracy of models is not perfect aircraft attitude accuracy > Some parameters remain unknown influence Remaining errors are smoothed in final trend. oil temperature influence Accuracy improvement lowers detection time oil flow influence Some robustness may be also included in threshold detection (k among n)
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Sensor technology selection is influenced by the Flight engine specificities Engine 2 Measure
Measurements come with sources of error 3 Compute
Recovery methods are defined 1 Transmit
Ground station
Maximum transmission bandwidth known Data and trueness recovery methods identified ? How to implement data acquisition and recovery methods ?
91 June 2017 / R& T 1 2 33 4 Q This document and the information therein are the property of Safran. They must not be copied or communicated to a third party without the prior written authorization of Safran part CHAPTER 3 CONTENTS 3
Measurement Choice of Sensors Accuracy retrieval methods
Computation
Hardware in Engine Envrionment
1 2 Computation Optimization
Transmission Aircraft to Ground Engine to Aircraft
Mars 2016 / DIRECTION SUPPORT CLIENTS 1 2 33 4 Q This document and the information therein are the property of Safran. They must not be copied or communicated to a third party without the prior written authorization of Safran Chapter 3 Part 3 COMPUTE - Embedded computational unit vs. Smartphone 1/9
~-50°C ~ 100°C Lightning ~ -20°C ~ 45°C Altitude
CPU, RAM, NVM ~ 10 x Vibration
Development Duration Cosmic radiation
Each year, a new ~ 5-10 years development smartphone ~ 20-30 years in service
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Thermal dissipation Lithography miniaturization resolution Active cooling Increase sensitivity Component extended CONSTRAINTS temperature range reliability Different dilatation coefficient Cosmic rays shear
Data/code Component BGA grid vibrations corruption obsolescence resolution shear
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Hardware limitations • Storage memory less than 1 GB (several GB for ACMS) • CPU throughput generally less than 1 Gflop
Extra development efforts • Storage optimization (number of bits reduced to 8 when possible, undersampling, …) • Computation time is not only linked to the number of operations but also to the amount of data to load to the CPU Effort is spent in reduction of the number of operations Effort is also spent on the reduction on the bandwidth between memories and CPU: data flow optimization and cache usage
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Number of inputs is reduced:
• Flight phase restricted to domains aircraft attitude are limited N2 Core Speed Oil temperature • Aircraft attitude have been Oil level characterized in retained flight phases and aircraft data have been removed from inputs
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Number of outputs is reduced: Extracted samples
• Only samples bringing information are extracted
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Several PHM functions embedded in the same unit Altitude
Quantity of operation exceeds real time capability Scheduling
Treatment is differed and prioritized
time Startup processing Taxi out oil data Take off gas path data sensors data Gas path cruise data taxi in oil data Post flight report (PFS)
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Generally, more than 50% of computation time is spent in exchanging data between CPU and memories • It is generally better to work on small chunks of data • Keep data in cache memory as long as possible to avoid multiple Processor load/store cycles • Compromise between differed time that requires extra data exchange and real time for lighter algorithms that reduces data exchange L1 cache L1 cache program data
L2 cache Spatial and temporal proximity
External RAM
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Prototyping with scripting interpreted languages introduce a different data flow philosophy • Example : extracting a maximum and a minimum
Interpreted Embedded Processor (prototyping)
M = Max(X_vect)); For all x in X_vect L1 cache L1 cache m = min(X_vect)); if x > M program data M = x Max : end if For all x in X_vect L2 cache if x > M if x < m M = x m =x end if min : end if End for For all x in X_vect if x < m m = x End for External RAM end if End for Code optimization : advices completely opposite between This can increase the data flow bandwidth by more than 1000% interpreted script and embedded software
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Hardware limitations due to engine environment Flight Engine 2 Measure Need to simplify and optimize embedded computation 3 Compute • Reduce the number of operations • Reduce data flow exchange
1 Transmit
Ground station
Maximum transmission bandwidth known Data and trueness recovery methods identified Data acquisition and trueness recovery methods implemented
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Engine-aircraft and aircraft-ground bandwidth introduces the need of a data compression • Lossless compression may be impossible
Embedded constraints may limit the compression capability
Data loss rate is to be tuned in function of the available bandwidth, the computing capability and the monitoring accuracy need
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SAFRAN AIRCRAFT ENGINES PHM / TUTORIAL CONTENTS 1/22
Global PHM System Architecture System perimeter Engine dysfunction analysis Engine wear modes OPERATIONAL REALIZATIONS System architecture
PHM Systems on CFM56 & Silvercrest engine Gaining in confidence 1 2 3 in a PHM System Predictive & Effective maintenance
Introduction & Context Embedding a PHM System Why PHM for Aircraft Engines ? Constraints on airborne systems Harsh environment & monitoring
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CHAPTER 4 CONTENTS 2/22
Gaining confidence in PHM System Industrialization of PHM System Iterative process 1 2 3
Safran Monitoring Systems Predictive & Effective maintenance CFM56 Certification of PHM Systems Silvercrest Lifing on Engine Data collection Configuration Tracking
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Chapitre 4 3/22
Présentation systèmes de monitoring Safran
CFM56 : ACARS & GMS v2 solution
Forevision : A new step in monitoring by Safran.
Gaining confidence
Industrialization & Maturity (EIS / EIS +3)
Predictive & effective maintenance
challenge of PHM systems is to help maintenance to gain in prediction & effectiveness.
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Gaining confidence in PHM System Safran Monitoring Industrialization of PHM System Iterative process Systems
CFM56 Silvercrest Data collection 2 3
Predictive & Effective maintenance Certification of PHM Systems Lifing on Engine Configuration Tracking
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Mature Engines CFM56 & SaM146 New Engines like Leap or Silvercrest
• Limited monitoring due to available data • Embedded Monitoring system designed by the on aircraft avionics. OEM to control the data generation.
• New development are hindered by complexity to • Global system approach to be sure to have an add a new system that is to be certified after EIS. optimized ground & embedded systems.
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Functions Needs Diagram General Oil system •Anomaly detection •Oil & Pressure monitoring •Fusion decision making •Filter by-pass •Fleet mapping •Oil consumption •Debris monitoring & Smart filters Control system •Sensor checking •Actuator checking Fuel system •Aided troubleshooting •Filter by-pass Performances •Fault isolation •Smart filters •Global analysis •Fuel pump monitoring •Modular analysis
Mechanical health Start capability •Balancing analysis •Hot /Hung start •Bearings & gears •Start system health •Fleeting events •Sparks health
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GMS ACARS
ACMS GMS Diag export Data Query loading tools
Transfer to the ground orchestration engineering 3 possibilities (depending on the application) ReGen The CFM International CFM56 (U.S. During the flight (ACARS) algorithms military designation F108) series is a family End of the flight (GSM or SPC, Trends, Alert of high-bypass turbofan aircraft engines WiFi) made by CFM International (CFMI), with a thrust range of 18,500 to 34,000 pounds- At Scheduled time force (82 to 150 kilonewtons). diagnostics Number built 30,000 (as of July 2016) Unit cost US$10 million (list price) 1 2 3 Q 109June 2017 / R& T 4 This document and the information therein are the property of Safran. They must not be copied or communicated to a third party without the prior written authorization of Safran Chapter 4 Part 1 CFM56 8/22
Performance (EGT trend, score)
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Snapshot taken when the level is changing and only during ground idle phase.
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More than 10000 EFH of raw data stored. Since 2012, some Safran ACMS does that Distance between regression computation on lines estimates the oil Lost report fleet. servicing quantity Regression slope is the average consumption between 2 servicing
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Silvercrest fleet will be monitored by Safran Aircraft Engines’ front office . follow the sun organization among 3 hubs
Data is generated all along the flight . before engine start . after engine shutdown
Data is transferred . during the flight for dispatch information . after the flight for non dispatch information
Data is automatically processed on ground
Results are analyzed . by front office for short term assessments When a shift occurs, an alarm is raised, then investigated Customer support delivers a maintenance recommendation to the customer . by back office for mid-long term assessments . Data and analysis results are available on a secured web portal for customers 1 2 3 Q 113June 2017 / R& T 4 This document and the information therein are the property of Safran. They must not be copied or communicated to a third party without the prior written authorization of Safran Chapter 4 Part 1 SCR Functional perimeter 12/22 Silvercrest Engine Health Management is Nacelle Monitoring based on Safran Aircraft Engines Thrust Reverser Actuation System
Algorithms able to: Nacelle Anti Ice Valve
Controls Performance Analysis
Performance Condition Actuator Loop Monitoring Engine Oil Condition Performance Health Monitoring Engine Start Capability
Sensors Intermittences
Actuator Use
Smart Filter Mechanical Diagnostics Sensors Aging Drift Unbalance Modular Analysis Mission Cycle Count Bearing Monitoring
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MMS GMS ACARS
Forevision Thrust range 10,000-12,000 lbf Data Qurey loading tools (44-53 kN) Engine Engine orchestration
algorithms Portal Transfer to the ground 2 possibilities (depending on the SPC, Trends, Alert application) During the flight (SATCOM) Scheduled time
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Gaining confidence in PHM System Industrialization of PHM System 1 Iterative process 3
Predictive & Effective maintenance Certification of PHM Systems Safran Monitoring Systems Lifing on Engine CFM56 Configuration Tracking Silvercrest Data collection
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Gaining confidence in PHM System Industrialization of PHM System Iterative process Predictive & Effective maintenance Certification of 1 2 PHM Systems
Safran Monitoring Systems CFM56 Silvercrest Data collection
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PHM in Safran is dedicated mainly on events tracking. Such as D&C, ATO and IFSD And it complete the PSE offer of services to trend. Certified PHM is when the function of the system dedicated to data recording is at least Certified PHM zone certified level D. Then the produced data have credit with respect to EASA or FAA.
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