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| 1 CFM International CFM Product Support Engineering - February 24, 2006 Proprietary Information FADEC System Fault
 Strategy and Troubleshooting
 Presented by
 Bill Benham
 CFM Product Support Engineering
 2 CFM International CFM Product Support Engineering - February 24, 2006 Proprietary Information
 CCFFMM5566--77BB
 FADEC SYSTEM FAULT
 STRATEGY & TROUBLESHOOTING
 FADEC SYSTEM FAULT
 STRATEGY & TROUBLESHOOTING
 CFM International Proprietary Information – The information contained in this document is CFM International (CFM) proprietary
 information and is disclosed in confidence. It is the property of CFM and shall not be used, disclosed to others or reproduced without the
 express written consent of CFM, including, but without limitation, it is not to be used in the creation, manufacture, development, or derivation
 of any repairs, modifications, spare parts, designs, or configuration changes or to obtain FAA or any other government or regulatory approval
 to do so. If consent is given for reproduction in whole or in part, this notice and the notice set forth on each page of this document shall
 appear in any such reproduction in whole or in part. The information contained in this document may also be controlled by the U.S. export
 control laws. Unauthorized export or re-export is prohibited.
 3 CFM International CFM Product Support Engineering - February 24, 2006 Proprietary Information
 !!! NOTICE !!!
 This document is intended for TRAINING purposes
 only and does not replace the pertinent
 manufacturer's Maintenance Manual.
 The information was accurate at time of the
 compilation, however, the data will not be updated
 to maintain accuracy.
 4 CFM International CFM Product Support Engineering - February 24, 2006 Proprietary Information
 FADEC SYSTEM FAULT
 STRATEGY
 CFMI Proprietary Information
 The information contained in this document is CFMI Proprietary Information and is disclosed in confidence. It is the property of CFMI and shall
 not be used, disclosed to others or reproduced without the express written consent of CFMI. If consent is given for reproduction in whole or in
 part, this notice and the notice set forth on each page of this document shall appear in any such reproduction in whole or in part. The
 information contained in this document may also be controlled by the U.S. export control laws. Unauthorized export or re-export is prohibited.
 5 CFM International CFM Product Support Engineering - February 24, 2006 Proprietary Information
 FAULT MANAGEMENT
 • Detection
 – Control Loop Faults
 – Input Sensor Faults
 – Filter Switch Faults
 – ID Plug Faults
 • Storage
 • Accommodation / Selection
 • Dispatch Levels
 • Annunciation
 6 CFM International CFM Product Support Engineering - February 24, 2006 Proprietary Information
 FAULT DETECTION
 • The engine control system maintenance is assisted by
 extensive EEC internal Built-In-Test logic providing efficient
 fault detection.
 During Normal Mode operation, the EEC:
 » Monitors engine data and EEC status flags to detect engine
 failures
 » Determines engine dispatch level based on current faults
 » Stores in the EEC BITE memory the
  dispatch level
  fault code
  fault data
 7 CFM International CFM Product Support Engineering - February 24, 2006 Proprietary Information
 FADEC System Overview FAULT DETECTION
 AIRFRAME
 Start Lever
 Thrust-Lever Resolver
 Bleed Data
 Flight Data
 Autothrottle Data
 Start/Ignition commands
 Thrust-Lever Interlock
 Thrust Reverser LVDT’s
 Status reporting
 Maintenance Reporting
 Engine reporting
 Alternate EEC Power
 Ignition Power Electronic Engine Control (EEC)
 Upper
 Ignition
 Exciter
 Lower
 Ignition
 Exciter Fuel
 Metering
 Valve
 Overspeed
 Governor
 Hydraulic
 Interface
 Electrical
 Interface
 METERED
 FLOW
 Primary
 Air
 Flow
 Active
 Clearance
 Control
 Stability
 Bleed
 VBV Actuators
 HPTACC Valve
 LPTACC Valve
 TB Valve
 VSV Actuators
 Position Feedbacks
 Hydro-Mechanical Unit (HMU)
 HPSOV
 EEC
 Alternator
 Engine
 Speeds
 Engine
 Pressures
 Engine
 Temps
 Fuel
 Flow
 ID
 Plug
 8 CFM International CFM Product Support Engineering - February 24, 2006 Proprietary Information
 Typical Control Loop FAULT DETECTION
 Hydraulic
 Electric
 • EEC
 » 2 independent channels
  ACTIVE - drives control current to the HMU until feedback indicates actuator is in proper position
  STANDBY - does not drive control current, but able to take control instantaneously
 » Communication through Cross Channel Data Link (CCDL)
 • HMU
 » Converts EEC control current input into fuel pressure output to the actuator
 • ACTUATOR
 » Positioned by HMU output pressure
 » Two independent channels of feedback to the EEC
 » Feedback shared between channels through Cross Channel Data Link
 ACTUATOR
 EEC HMU
 CCDL Torque
 Motor
 Channel A
 Channel B
 Pilot
 Valve
 Demand
 Position Feedback
 Position Feedback
 9 CFM International CFM Product Support Engineering - February 24, 2006 Proprietary Information
 Types of Faults FAULT DETECTION
 1. Control Current Out of Range
 2. Demand and Position Signals Disagree
 3. Position Signal Out of Range
 4. Position Signals Disagree
 5. Sensor Out of Range
 6. Sensor Disagree
 7. ID Plug
 8. Excitation Circuit (Multiple Position Signal Out of Range Faults)
 1. Control Current Out of Range
 2. Demand and Position Signals Disagree
 3. Position Signal Out of Range
 4. Position Signals Disagree
 5. Sensor Out of Range
 6. Sensor Disagree
 7. ID Plug
 8. Excitation Circuit (Multiple Position Signal Out of Range Faults)
 10 CFM International CFM Product Support Engineering - February 24, 2006 Proprietary Information
 Control Loop Faults FAULT DETECTION
 • Control Current out of Range Fault
 Potential causes
 - HMU (Electrical portion)
 - EEC
 - Harness
 POTENTIAL
 CAUSES
 Channel A ACTUATOR
 Channel B
 CCDL
 EEC
 Torque
 Motor Pilot
 Valve
 HMU
 MAINT MSG
 73-x032n
 75-x037n
 75-x042n
 75-x047n
 75-x052n
 75-x056n
 75-x057n
 73-x062n
 MAINT MSG
 73-x032n
 75-x037n
 75-x042n
 75-x047n
 75-x052n
 75-x056n
 75-x057n
 73-x062n
 11 CFM International CFM Product Support Engineering - February 24, 2006 Proprietary Information
 • Control Current out of Range Fault - torque motor
 {FMV, VSV, VBV, HPTACC, LPTACC, TBV}
 » EEC checks torque motor / solenoid circuit integrity
 » Control Current Out of Range Fault generated on the active channel
 if:
  difference between i1 and i2 is greater than 50 mA
  or i2 > 365 mA
  and fault persists for more than 4.8 seconds
 EEC
 active channel
 i 1
 i 2
 TORQUE MOTOR /
 SOLENOID - Normal operation i1 = i2
 Control Loop Faults FAULT DETECTION
 NOTE : THESE TYPES OF FAULT LEAD TO A CHANGE IN ACTIVE CHANNEL
 12 CFM International CFM Product Support Engineering - February 24, 2006 Proprietary Information
 Control Loop Faults FAULT DETECTION
 • Control Current out of Range Fault EXAMPLE # 1 : Short circuit
 to ground
 » Current flows through ground path back to the EEC
 » EEC detects i1 = i2
  A control current out of range fault message is generated
  Fault detection leads to change of channel in control
 EEC
 TORQUE MOTOR /
 SOLENOID
 i1
 i2
 SHORT CIRCUIT TO GROUND
 13 CFM International CFM Product Support Engineering - February 24, 2006 Proprietary Information
 • Control Current out of Range Fault EXAMPLE # 2 : Open circuit
 » i1 = i2 = 0 under all condition
 » EEC tries to generate a current i1 but can't because of the open
 circuit
  A control current out of range fault message is generated
  Fault detection leads to change of channel in control
 EEC
 TORQUE MOTOR
 i1
 i2
 Control Loop Faults FAULT DETECTION
 14 CFM International CFM Product Support Engineering - February 24, 2006 Proprietary Information
 • Control Current out of Range Fault EXAMPLE # 3 : Line to line
 short circuit
 » EEC detects i1 = i2
 » EEC cannot detect if this short circuit exists
  NO control current out of range fault message generated
  No change of channel in control
 » EEC loses control over torque motor / solenoid function
  A servo/solenoid Demand/Position Disagree Fault will be generated
 EEC
 i1 TORQUE MOTOR
 i2
 Control Loop Faults FAULT DETECTION
 15 CFM International CFM Product Support Engineering - February 24, 2006 Proprietary Information
 Control Loop Faults FAULT DETECTION
 • Demand and Position Signals Disagree
 • Potential causes
 - HMU (hydraulic portion)
 - Actuator
 - Fuel lines
 MAINT MSG
 (SERVO)
 73-x033n
 75-x038n
 75-x043n
 75-x048n
 75-x053n
 75-x058n
 MAINT MSG
 (SERVO)
 73-x033n
 75-x038n
 75-x043n
 75-x048n
 75-x053n
 75-x058n
 POTENTIAL
 CAUSES
 Channel A ACTUATOR
 Channel B
 CCDL
 EEC
 Torque
 Motor
 Pilot
 Valve
 HMU
 MAINT MSG
 (SOLENOID)
 73-x063n
 73-x064n
 MAINT MSG
 (SOLENOID)
 73-x063n
 73-x064n
 16 CFM International CFM Product Support Engineering - February 24, 2006 Proprietary Information
 • Demand and Position Signals Disagree (SERVO) {FMV, VSV, VBV,
 HPTACC, LPTACC, TBV}
 » EEC checks if the sensed (measured) actuator position agrees
 with demanded position.
 » Servo position fault generated on the active channel if :
  Sensed actuator position disagrees with demanded actuator position
 by more than 5% (10% for TBV with 7BQ).
  Fault persists for more than 4.8 seconds (9.6 sec for TBV with 7BQ)
  N2 is greater than 22 %
  There is no Position Signal Fault at that moment
  There is no torque motor Control Current Out of Range Fault at that
 moment
 Control Loop Faults FAULT DETECTION
 17 CFM International CFM Product Support Engineering - February 24, 2006 Proprietary Information
 Control Loop Faults FAULT DETECTION
 • Position Signal Out of Range Fault
 • Potential causes
 - Actuator LVDT/RVDT/Resolver
 - EEC
 - Harness
 MAINT MSG
 (LVDT/RVDT)
 75-x039n
 75-x044n
 75-x049n
 75-x054n
 75-x059n
 79-x109n
 MAINT MSG
 (LVDT/RVDT)
 75-x039n
 75-x044n
 75-x049n
 75-x054n
 75-x059n
 79-x109n
 MAINT MSG
 (Resolver)
 73-x034n
 MAINT MSG
 (Resolver)
 73-x034n
 Channel A ACTUATOR
 Channel B
 CCDL
 EEC
 Torque
 Motor
 Pilot
 Valve
 HMU
 POTENTIAL
 CAUSES
 18 CFM International CFM Product Support Engineering - February 24, 2006 Proprietary Information
 Control Loop Faults FAULT DETECTION
 • Position Signal Out of Range Fault RVDT / LVDT
 {VSV, VBV, HPTACC, LPTACC, TBV, PEO}
 RVDT / LVDT Consists of :
  1 primary winding
  2 secondary windings
  1 moveable core
 » EEC inputs constant voltage to primary winding
 » Secondary voltages change as a function of core position
 V1
 V2
 V1 = V2
 0% 50% 100%
 0
 V
 ACTUATOR POSITION
 V1
 V2
 VEX
 V V EX RMS  7.07  0.16
 Secondary 1
 Secondary 2
 Primary
 5-wire LVDT
 19 CFM International CFM Product Support Engineering - February 24, 2006 Proprietary Information
 • Position Signal Out of Range Fault Resolver
 {FMV}
 Resolver used for better accuracy compared to RVDT / LVDT
 » Resolver consists of :
  1 Primary winding (rotating)
  2 secondary windings (sine and cosine)
 » EEC inputs constant voltage to primary winding
 » Secondary voltage (sine and cosine) change as a function of core position
 Control Loop Faults FAULT DETECTION
 COSINE
 SINE
 ROTATING PART
 90
 SINE
 COSINE
 0
 0.1
 0.2
 0.3
 0.4
 0.5
 0.6
 0.7
 0.8
 0.9
 1
 0 10 20 30 40 45 50 60 70 80 90
 Angular position
 V
 20 CFM International CFM Product Support Engineering - February 24, 2006 Proprietary Information
 Control Loop Faults FAULT DETECTION
 • Position Signal Out of Range Fault
 » EEC checks output voltage validity
 » Position Signal Out of Range Fault generated if :
 – V1 or V2 is out of range
 – Sum of V1+V2 out of range (RVDT/LVDT) or
 – (sine voltage)2 + (cosine voltage)2 is out of range (Resolver)
 – Calculated position out of range
 – Fault persists for more than 4.8 seconds
 21 CFM International CFM Product Support Engineering - February 24, 2006 Proprietary Information
 Control Loop Faults FAULT DETECTION
 • Position Signals Disagree Fault
 Potential causes
 - Actuator LVDT/RVDT/Resolver
 - EEC
 - Harness
 MAINT MSG
 (LVDT/RVDT)
 75-x040n
 75-x045n
 75-x050n
 75-x055n
 75-x060n
 MAINT MSG
 (LVDT/RVDT)
 75-x040n
 75-x045n
 75-x050n
 75-x055n
 75-x060n
 EEC
 Channel A ACTUATOR
 Channel B
 CCDL Torque
 Motor
 Pilot
 Valve
 HMU
 POTENTIAL
 CAUSES
 MAINT MSG
 (Resolver)
 73-x035n
 MAINT MSG
 (Resolver)
 73-x035n
 22 CFM International CFM Product Support Engineering - February 24, 2006 Proprietary Information
 • Position Signals Disagree Fault (RVDT / LVDT / Resolver)
 {VSV, VBV, HPTACC, LPTACC, TBV, FMV}
 » EEC checks that the position sensed by channel A agrees with the position
 sensed by channel B.
 » Position Signal Disagree Fault generated if :
  the absolute difference of the positions sensed by channels A and B is greater
 than a certain value.
  there is no Position Signal Fault at that moment.
  fault persists for more than 4.8 seconds.
 Control Loop Faults FAULT DETECTION
 DIFF Fault absolute difference
 FMV: >2.0 %
 VSV: >0.3 in
 VBV: >4.0 deg
 HPTACC: >8.7%
 LPTACC: >3.0%
 TBV: >8.7%
 NOTE: THIS FAULT SHOULD BE SET ON BOTH CHANNELS. IF
 NOT, THERE IS AN ADDITIONAL INTERNAL EEC FAILURE.
 23 CFM International CFM Product Support Engineering - February 24, 2006 Proprietary Information
 Control Loop Faults FAULT DETECTION
 • Position Signals Disagree Fault (SWITCH)
 Potential causes
 - BSV Switch
 - EEC
 - Harness
 MAINT MSG
 73-x065n
 MAINT MSG
 73-x065n
 Channel A
 Channel B
 CCDL
 EEC
 BURNER STAGING VALVE
 Torque
 Motor
 Pilot
 Valve
 HMU
 POTENTIAL
 CAUSES
 24 CFM International CFM Product Support Engineering - February 24, 2006 Proprietary Information
 • SENSOR OUT OF RANGE FAULT
 - Pressure sensors: P0, P25, PS13, PS3.
 NOTE: PEO is a simulated LVDT, thus fault detection is done as described on page 17.
 - VRT Temperature sensors: T12, T25, TEO, TEEC.
 - Thermocouple Temperature sensors: T3, EGT, TCC, T5.
 - Speed sensors: N1, N2.
 » EEC checks output signal validity
 » Sensor fault generated if:
  the sensed pressure/temperature is out of range.
  fault persists for more than 4.8 seconds.
 » EEC sets the fault on the faulty channel
 MAINT MSG
 73-x017n
 73-x018n
 73-x075n
 73-x076n
 73-x077n
 73-x081n
 73-x082n
 75-x083n
 77-x084n
 77-x085n
 77-x086n
 77-x087n
 75-x088n
 75-x089n
 79-x110n
 77-x117n
 77-x118n
 MAINT MSG
 73-x017n
 73-x018n
 73-x075n
 73-x076n
 73-x077n
 73-x081n
 73-x082n
 75-x083n
 77-x084n
 77-x085n
 77-x086n
 77-x087n
 75-x088n
 75-x089n
 79-x110n
 77-x117n
 77-x118n
 Input Sensor Faults FAULT DETECTION
 25 CFM International CFM Product Support Engineering - February 24, 2006 Proprietary Information
 • SENSOR DISAGREE FAULT
 - Sensors: T12, TAT, Po, N2
 » Sensor Disagree Fault generated if:
  the absolute difference of the compared signals is greater than a certain value.
  fault persists for more than 4.8 seconds.
 » EEC checks that channel A T12 signal agrees with channel B T12 signal.
 » EEC checks that TAT1 and TAT2 signal agrees with the local T12 signal.
 » EEC checks that PS1 and PS2 signals agrees with Po signal.
 » EEC checks that channel A N2 signal agrees with channel B N2 signal.
 » EEC sets the fault on both channels
 Input Sensor Faults FAULT DETECTION
 MAINT MSG
 73-x090n
 73-x168n
 73-x170n
 77-x113n
 MAINT MSG
 73-x090n
 73-x168n
 73-x170n
 77-x113n
 26 CFM International CFM Product Support Engineering - February 24, 2006 Proprietary Information
 Filter Switch Faults FAULT DETECTION
 • FILTER SWITCH DISAGREE FAULT {Fuel and Oil Filters}
 » EEC checks if both position switches agree (one switch open / one switch closed)
 » Switch Disagree fault generated if:
  airplane is on the ground for more than 90 seconds AND
  the position sensed by switch 1 and 2 are the same
 OR
  the active and standby EEC channels disagree.
  fault persists for more than 30 seconds.
 MAINT MSG
 73-x107n
 79-x112n
 MAINT MSG
 73-x107n
 79-x112n
 EEC
 SWITCH 1
 SWITCH 2
 Channel B
 CCDL
 Channel A
 27 CFM International CFM Product Support Engineering - February 24, 2006 Proprietary Information
 • Identification plug
 » includes the engine identification/configuration:
  Engine Thrust Rating and Parity
  N1 Trim Level and Parity
  Engine Combustor Configuration (SAC/DAC) and Parity
  Engine Condition Monitoring (PMUX)
 » each identification/configuration infomation:
  is coded by a combination of closed/open discretes
  has an additional discrete for fault detection (parity discretes, except
 PMUX)
  coded such way that the total number of closed discretes is odd (odd
 parity check)
 Identification Plug Faults FAULT DETECTION
 28 CFM International CFM Product Support Engineering - February 24, 2006 Proprietary Information
 Identification Plug Faults FAULT DETECTION
 • Identification plug parity check (N1 Trim)
 » There must be an odd number of closed circuits to pass odd parity
 29 CFM International CFM Product Support Engineering - February 24, 2006 Proprietary Information
 • ID Plug Fault (73-x132n)
 » Fault is generated if
  configuration and rating parity checks are not ODD *
  plug type is not valid
 • N1 Trim Fault (73-x133n)
 » Fault is generated if trim parity check is not ODD *
 • Engine Rating Out Of Range Fault (73-x141n)
 » Fault is generated if
  there is no "ID Plug" Fault
  engine rating is not valid.
 * odd parity check: see page 29
 Identification Plug Faults FAULT DETECTION
 30 CFM International CFM Product Support Engineering - February 24, 2006 Proprietary Information
 Identification Plug Faults FAULT DETECTION
 • Airplane Model and Engine Rating Disagree (73-x142n)
 » Fault is generated if
  there is no "Airplane Model Out Of Range" Fault
  there is no "Engine Rating Out Of Range" Fault
  there is no "ID Plug" Fault
  combination of engine rating and aircarft model is not valid.
 • EEC also monitors airplane discretes;
 » Airplane Model Out Of Range Fault (73-x139n)
  Fault is generated if airplane model is not valid.
 » Engine Position Error Fault (73-x138n)
  Fault is generated if engine position is neither 1 nor 2.
 31 CFM International CFM Product Support Engineering - February 24, 2006 Proprietary Information
 FLIGHT LEG STORAGE PROCESSING
 • Fault storage
 » is a function of A/C
 and engine status
 » at GRD to FLT
 transition, all leg 0
 faults are transferred
 to leg 1
 GROUND -> FLIGHT >
 FLIGHT -> GROUND >
 EEC POWER UP >
 FLIGHT IND = GROUND
 ENG START >
 FLIGHT IND = FLIGHT >
 FLIGHT IND = GROUND >
 (for at least 30 sec)
 ENGINE SHUTDOWN >
 EEC POWER OFF >
 ENGOFF ENGON FLTCYC
 N2 > 40%
 GROUND RUN FAILURES
 FLIGHT 0 FLIGHT 1
 GROUND FLIGHT GROUND
 Faults Not
 Stored in
 “NVM”
 Faults Not
 Stored in
 “NVM”
 (Increment Flight Leg)
 ENGINE 1 BITE TEST
 FAULT HISTORY
 SHORT TIME
 3/5
 HISTORY >
 MSG NBR: 75-10601
 THE TBV POSITION
 SIGNALS DISAGREE
 FLIGHT LEG (X=FAULT SET)
 0 1 2 3 4 5 6 7 8 9 10
 X X X
 < INDEX
 32 CFM International CFM Product Support Engineering - February 24, 2006 Proprietary Information
 FAULT ACCOMMODATION / SELECTION
 • Both Channels in Range and In Agreement
 » Value = (Channel A + Channel B) / 2
 • One Channel in Range and One Channel Out of Range
 (Single Channel Fault Accommodation)
 » Airplane input signal (P0, TAT, PT)
  a correlation input between engine sensors and remaining ADIRU
 is selected.
 » Engine input signals and TRA airplane input
  the valid signal is used
 » EEC Internal Fault
  the stand-by channel assumes the role of the in-control channel.
 33 CFM International CFM Product Support Engineering - February 24, 2006 Proprietary Information
 FAULT ACCOMMODATION / SELECTION
 • Both Channels In Range But Not In Agreement
 » N1, N2, Ps3, T25 - Channel Closest to Model selected
 – Model based on other inputs - e.g. N2 Model = fn(Ps3, T25, Mo, N1, TAT)
 » VSV, VBV - Channel Closest to Servo Actuator Model selected
 – Servo Model based on history of control current inputs
 » FMV - Uses a Delta Sum-of-Squares Weighted Average Algorithm
 » TBV, HPTACC, LPTACC - The higher of the two channels is selected
 » TRA - The lower of the two channels is selected
 • Both Channels In Range But Not In Agreement
 » N1, N2, Ps3, T25 - Channel Closest to Model selected
 – Model based on other inputs - e.g. N2 Model = fn(Ps3, T25, Mo, N1, TAT)
 » VSV, VBV - Channel Closest to Servo Actuator Model selected
 – Servo Model based on history of control current inputs
 » FMV - Uses a Delta Sum-of-Squares Weighted Average Algorithm
 » TBV, HPTACC, LPTACC - The higher of the two channels is selected
 » TRA - The lower of the two channels is selected
 34 CFM International CFM Product Support Engineering - February 24, 2006 Proprietary Information
 • Both Channels Out of Range
 (Dual Channel Fault Accommodation)
 » Thrust control input signals (T25, PS3, N1, N2, FMV, VSV, VBV)
  a synthesis model is selected.
 – Thrust control input signal (TRA airplane input)
  a fail-safe of idle is selected
 » Indication inputs, non-critical systems control inputs (TC, TEO,
 TECU, HPTC, TBV, PEO, LPTC)
  a fail-safe is selected.
 » EGT input (4 inputs total - 2 per channel)
  a weighted average of the remaining valid signals is selected
 » WFM indication input
  a calculated value is selected (based on FMV).
 FAULT ACCOMMODATION / SELECTION (cont'd)
 35 CFM International CFM Product Support Engineering - February 24, 2006 Proprietary Information
 DISPATCH LEVELS
 • EEC automatically determines
 » criticality level of the fault or combination of faults
 » the dispatch state of the propulsion system to comply with the engine and
 airplane safety objectives
 • The fault-dispatch levels are defined as follow:
 » Level A: "Engine Control Light". Fault correction prior A/C dispatch
 » Level B: "Short-Time". Fault correction within next 150 - I FH
 » Level C: "Long-Time". Fault correction within next 500 - I/2 FH
 » Level D: "Economic". No time limitation.
 » Level E: "Alternate-Mode Light". Check Dispatch Deviation Guide/MMEL
 I = fault inspection interval
 36 CFM International CFM Product Support Engineering - February 24, 2006 Proprietary Information
 group D fault NO Time Limit group E fault See DDG/MMEL
 ALTN MODE
 FAULTS DISPATCH LEVEL CRITERIA
 SHORT Time Dispatch LONG Time Dispatch
 group B fault group C fault
 NO Dispatch
 group A fault
 group  fault group  fault group  fault group T495 fault
 YES
 YES
 YES
 YES
 NO
 NO
 NO
 NO
 EEC
 CCDL
 ACTIVE
 
  faults
 STANDBY
 inop
 EEC
 CCDL
 ACTIVE
  fault
 STANDBY
 any other
  fault
 EEC
 CCDL
 ACTIVE
  fault
 STANDBY
 same 
 fault
 EEC
 CCDL
 ACTIVE
  fault
 STANDBY
 same 
 fault
 EEC
 fault
 on
 ACTIVE
 or
 STANDBY
 EEC
 more than
 2 faults
 ACTIVE
 and
 STANBY
 EEC
 CCDL
 ACTIVE
 STANDBY
 inop
 faults
 EEC
 CCDL
 ACTIVE
 STANDBY
 inop
 T495
 faults
 group  fault
 YES
 NO
 37 CFM International CFM Product Support Engineering - February 24, 2006 Proprietary Information
 FAULT ANNUNCIATION
 ENGINE
 REVERSER
 1
 REVERSER
 2
 EEC
 ALTN
 ON
 EEC
 ALTN
 ON ENGINE
 CONTROL
 ENGINE
 CONTROL
 • In-Flight
 » Level A Fault
  CDS DOES NOT turn on the amber
 ENGINE CONTROL
 » Level B through D faults (Dispatch)
  not actively annunciated in the flight
 compartment
  to be periodically checked for by the
 maintenance crew
 » Level E fault (alternate thrust-setting
 mode)
  annunciated by the ALTN indicator light.
 38 CFM International CFM Product Support Engineering - February 24, 2006 Proprietary Information
 ENGINE
 REVERSER
 1
 REVERSER
 2
 EEC
 ALTN
 ON
 EEC
 ALTN
 ON ENGINE
 CONTROL
 ENGINE
 CONTROL
 FAULT ANNUNCIATION
 • On Ground*
 » Level A Fault (No-Dispatch)
  CDS turns on the amber ENGINE
 CONTROL
 » Level B through D faults (Dispatch)
  not actively annunciated in the flight
 compartment
  to be periodically checked for by the
 maintenance crew
 » Level E fault (alternate thrust-setting
 mode)
  annunciated by the ALTN indicator light.
 * On Ground Taxi/Takeoff: Less than 80 kt,
 * On Ground Landing: A/C on GRD Less than 80 kt for 30 seconds
 39 CFM International CFM Product Support Engineering - February 24, 2006 Proprietary Information
 FAULT ANNUNCIATION
 • OIL FILTER BYP LIGHT
 » Provide flight crew with an impending engine oil filter bypass indication
 » EEC constantly provides CDS with sensed filter condition
 » In flight, light is illuminated if
 » an impending bypass is detected for more than 60 seconds BUT
 » there is no oil filter delta P switch fault (ref page 26)
 » On ground, light is illuminated if
 » an impending bypass is detected for more than 60 seconds AND/OR
 » there is an oil filter delta P switch fault (ref page 26)
 40 CFM International CFM Product Support Engineering - February 24, 2006 Proprietary Information
 FAULT ANNUNCIATION
 • FUEL FILTER BYP LIGHT
 » Provide flight crew with an impending engine fuel filter bypass
 indication
 » EEC constantly provides CDS with sensed filter condition
 » In flight, light is illuminated if
 » an impending bypass is detected for more than 60 seconds BUT
 » there is no fuel filter delta P switch fault (ref page 27)
 » On ground, light is illuminated if
 » an impending bypass is
 detected for more than 60
 seconds
 AND/OR
 » there is a fuel filter delta P
 switch fault (ref page 27)
 41 CFM International CFM Product Support Engineering - February 24, 2006 Proprietary Information
 HPSOV: High Pressure Shutoff Valve FAULT ANNUNCIATION
 Provides fuel shutoff capability independent of the FADEC System, wired directly
 between HMU and A/C
 Light Valve Position
 Bright Not in Commanded Position
 Off Open
 Dim Closed
 HPSOV: High Pressure Shutoff Valve
 Provides fuel shutoff capability independent of the FADEC System, wired directly
 between HMU and A/C
 Light Valve Position
 Bright Not in Commanded Position
 Off Open
 Dim Closed
 42 CFM International CFM Product Support Engineering - February 24, 2006 Proprietary Information
 HHPPSSOOVV:: HHigighhPPrreessssuurreeSShhuuttooffffVVaalvlvee
 »Starts: When the Engine Start Lever is moved from CUTOFF to IDLE,
 this removes the 28 Vdc from the HPSOV Close Solenoid.
 Simultaneously, the EEC commands the FMV to open which then
 provides pressure to open the HPSOV
 »Shutdown: When the Engine Start Lever is moved to the CUTOFF
 position or the Engine Fire Switch Handle is pulled, 28 Vdc is supplied
 to the HPSOV solenoid which causes the HPSOV to close
 »Starts: When the Engine Start Lever is moved from CUTOFF to IDLE,
 this removes the 28 Vdc from the HPSOV Close Solenoid.
 Simultaneously, the EEC commands the FMV to open which then
 provides pressure to open the HPSOV
 »Shutdown: When the Engine Start Lever is moved to the CUTOFF
 position or the Engine Fire Switch Handle is pulled, 28 Vdc is supplied
 to the HPSOV solenoid which causes the HPSOV to close
 43 CFM International CFM Product Support Engineering - February 24, 2006 Proprietary Information
 FAULT ANNUNCIATION
 EEnngginineeFFaailil
 • An amber ENG FAIL alert is displayed if:
 - The engine is already started and
 - N2 is below a sustainable idle speed (50%) and
 - Engine Start Lever is at IDLE
 • The alert remains set until:
 - The engine recovers or
 - The Engine Start Lever is moved to the CUTOFF position
 • An amber ENG FAIL alert is displayed if:
 - The engine is already started and
 - N2 is below a sustainable idle speed (50%) and
 - Engine Start Lever is at IDLE
 • The alert remains set until:
 - The engine recovers or
 - The Engine Start Lever is moved to the CUTOFF position
 44 CFM International CFM Product Support Engineering - February 24, 2006 Proprietary Information
 CFMI Proprietary Information
 The information contained in this document is CFMI Proprietary Information and is disclosed in confidence. It is the property of CFMI and shall
 not be used, disclosed to others or reproduced without the express written consent of CFMI. If consent is given for reproduction in whole or in
 part, this notice and the notice set forth on each page of this document shall appear in any such reproduction in whole or in part. The
 information contained in this document may also be controlled by the U.S. export control laws. Unauthorized export or re-export is prohibited.
 FADEC SYSTEM FAULT
 TROUBLESHOOTING
 45 CFM International CFM Product Support Engineering - February 24, 2006 Proprietary Information
 FADEC GROUND MAINTENANCE
 FUNCTIONS
 • Fault Reporting
 – CDU Interrogation
 • Ground Tests
 • Faults List & Dispatch Level
 46 CFM International CFM Product Support Engineering - February 24, 2006 Proprietary Information
 FAULT REPORTING
 • EEC-detected faults
 » stored in EEC memory
 » available on request through the Ground Maintenance Mode
 • NVM data display
 » at the flight-compartment Control Display Units (CDUs) through
 different menus:
  Recent Faults Menu
  Fault History Menu
  Identification and Configuration Menu
  Input Monitoring Menu (real time data)
  Control Loops
  Control Pressures
  Control Temperature
  Fuel System
  Oil System
  Engine Speed
  Discretes
 47 CFM International CFM Product Support Engineering - February 24, 2006 Proprietary Information
 CDU INTERROGATION
 • Main Menu access
  MAINT >
  ENGINE >
  ENGINE # >
  FMC establishing communications
 with EEC
  EEC sorting fault history data
 DIR
 INTC LEGS HOLD PROG DE
 P
 AR
 N1 R
 LIMI
 T
 FIX
 PREV
 PAGE
 NEXT
 PAGE
 EXE
 C
 A B C D E
 F G H I J
 K L M N O
 P Q R S T
 U V W X Y
 +/- Z DEL / CLR
 1 2
 4 5
 7 8
 3
 6
 9
 0
 INI BRT
 T
 RE
 F
 RTE CLB CRZ DES
 < IDENT
 < POS
 < PERF
 < TAKEOFF
 < APPROACH
 NAV DATA >
 MAINT >
 INIT REF INDEX
 ENGINE 1 BITE TEST
 INITIALIZING EEC 1
 EXCEEDANCE >
 ENGINE/EXCEED BITE INDEX
 < ENGINE 1
 < ENGINE 2
 < ENGINE 1 CH A ONLY
 < ENGINE 2 CH A ONLY
 < INDEX
 ENGINE 1 BITE TEST
 ENGINE MAINTENANCE
 CAN NOT BE ACCESSED
 THE ENGINE'S
 FLIGHT INDICATOR
 < INDEXSHOWS FLIGHT
 ENGINE 1 BITE TEST
 EEC SORTING
 FAULT HISTORY DATA
 THIS TAKES
 ABOUT 45 SECONDS
 < RECENT FAULTS
 < FAULT HISTORY
 < IDENT/CONFIG
 < GROUND TEST
 < INPUT MONITORING
 < INDEX
 ENGINE I BITE TEST
 MAIN MENU 1/1
 MAINT BITE INDEX 1/1
 < FMCS
 < DFCS
 < AT
 < ADIRS
 < CDS
 < INDEX
 ENGINE >
 APU >
 FQIS >
 48 CFM International CFM Product Support Engineering - February 24, 2006 Proprietary Information
 CDU INTERROGATION (cont'd)
 • Recent Fault Menu access and Features
 » Reports faults stored in NVM over last 3 flight legs
 » 1 fault per page
  sorted by dispatch level (most critical first)
 » display details as
  message number
  brief fault description
  recent flight legs fault history
 ENGINE 1 BITE TEST
 RECENT FAULTS
 ENGINE CONTROL LIGHT
 1/5
 HISTORY >
 MSG NBR: 73-10331
 THE FMV DEMAND
 AND POSITION SIGNALS
 DISAGREE
 FLIGHT LEG (X=FAULT SET)
 0 1 2 3
 X X
 < INDEX
 ENGINE 1 BITE TEST
 RECENT FAULTS
 ALTERNATE MODE LIGHT
 2/5
 HISTORY >
 MSG NBR: 73-11631
 THE ADIRU2
 TOTAL PRESSURE DATA
 IS MISSING FROM DEU2
 FLIGHT LEG (X=FAULT SET)
 0 1 2 3
 X X X
 < INDEX
 ENGINE 1 BITE TEST
 RECENT FAULTS
 SHORT TIME
 3/5
 HISTORY >
 MSG NBR: 75-10601
 THE TBV POSITION
 SIGNALS DISAGREE
 FLIGHT LEG (X=FAULT SET)
 0 1 2 3
 X X
 < INDEX
 ENGINE 1 BITE TEST
 RECENT FAULTS
 LONG TIME
 4/5
 HISTORY >
 MSG NBR: 74-11001
 THE APL INPUT VOLTAGE
 FOR THE R EXCITER
 IS ALWAYS ON
 FLIGHT LEG (X=FAULT SET)
 0 1 2 3
 X
 < INDEX
 ENGINE 1 BITE TEST
 RECENT FAULTS
 ECONOMIC
 5/5
 HISTORY >
 MSG NBR: 75-10531
 THE LPTACC DEMAND
 AND POSTION SIGNALS
 DISAGREE
 FLIGHT LEG (X=FAULT SET)
 0 1 2 3
 X X X
 < INDEX
 1/1
 < RECENT FAULTS
 < FAULT HISTORY
 < IDENT/CONFIG
 < GROUND TEST
 < INPUT MONITORING
 < INDEX
 ENGINE 1 BITE TEST
 MAIN MENU
 ENGINE 1 BITE TEST
 RECENT FAULTS
 ENGINE CONTROL LIGHT
 1/5
 HISTORY >
 MSG NBR: 73-10331
 THE FMV DEMAND
 AND POSITION SIGNALS
 DISAGREE
 FLIGHT LEG (X=FAULT SET)
 0 1 2 3 4 5 6 7 8 9 10
 X X X
 < INDEX
 49 CFM International CFM Product Support Engineering - February 24, 2006 Proprietary Information
 CDU INTERROGATION (cont'd)
 • Fault History Menu access and Features
 » Reports faults stored in NVM over last 10 flight legs
 » 1 fault per page
  sorted by dispactch level (most critical first)
 » display details as
  message number
  brief fault description
  most recent flight legs fault history
 » message number: AA-xDDDn
  AA = ATA Chapter
  x = EEC channel; 1=A, 2=B, 3=A and B
  DDD = unique fault code number
  n = Engine position; 0=Error, 1=ENG 1, 2=ENG 2 ENGINE 1 BITE TEST
 FAULT HISTORY
 SHORT TIME
 2/4
 HISTORY >
 MSG NBR: 75-10601
 THE TBV POSITION
 SIGNALS DISAGREE
 FLIGHT LEG (X=FAULT SET)
 0 1 2 3 4 5 6 7 8 9 10
 X X X
 < INDEX
 ENGINE 1 BITE TEST
 FAULT HISTORY
 LONG TIME
 3/4
 HISTORY >
 MSG NBR: 74-11001
 THE APL INPUT VOLTAGE
 FOR THE R EXCITER
 IS ALWAYS ON
 FLIGHT LEG (X=FAULT SET)
 0 1 2 3 4 5 6 7 8 9 10
 X X X X X X X X X X
 < INDEX
 ENGINE 1 BITE TEST
 FAULT HISTORY
 ECONOMIC
 4/4
 HISTORY >
 MSG NBR: 75-10531
 THE LPTACC DEMAND
 AND POSTION SIGNALS
 DISAGREE
 FLIGHT LEG (X=FAULT SET)
 0 1 2 3 4 5 6 7 8 9 10
 X X X X X X X
 < INDEX
 1/1
 HISTORY >
 < RECENT FAULTS
 < FAULT HISTORY
 < IDENT/CONFIG
 < GROUND TEST
 < INPUT MONITORING
 < INDEX
 ENGINE 1 BITE TEST
 MAIN MENU
 ENGINE 1 BITE TEST
 FAULT HISTORY
 ENGINE CONTROL LIGHT
 1/4
 HISTORY >
 MSG NBR: 73-10331
 THE FMV DEMAND
 AND POSITION SIGNALS
 DISAGREE
 FLIGHT LEG (X=FAULT SET)
 0 1 2 3 4 5 6 7 8 9 10
 X X
 < INDEX
 50 CFM International CFM Product Support Engineering - February 24, 2006 Proprietary Information
 CDU INTERROGATION (cont'd)
 • Identification - Configuration Menu access and Features
 » display details as shown in example below
 » displayed data are outputs from
  Aircraft
  EEC
  I.D plug
 ENGINE 1 BITE TEST
 IDENT / CONFIG 1/2
 AIRPLANE MODEL: 737-700
 ENGINE MODEL: 7B22
 BUMP 0
 N1 TRIM: 3
 EEC P/N 123456789A
 EEC S/W VER: 7B2A
 START MODE: ENHANCED
 <ENG S/N: 874-101
 < INDEX ERASE >
 1/1
 HISTORY >
 < RECENT FAULTS
 < FAULT HISTORY
 < IDENT/CONFIG
 < GROUND TEST
 < INPUT MONITORING
 < INDEX
 ENGINE 1 BITE TEST
 MAIN MENU
 ENGINE 1 BITE TEST
 IDENT / CONFIG 2/2
 PMUX INSTALLED: NO
 DMS KIT INSTALLED: YES
 BSV ENABLED YES
 IGNITION MODE: STANDARD
 < INDEX
 ENGINE 1 BITE TEST
 IDENT / CONFIG
 ENG S/N
 CONTINUE >
 TO CHANGE THE ENG S/N:
 - TYPE 6 DIGITS S/N
 - PUSH CONTINUE
 < GO BACK
 51 CFM International CFM Product Support Engineering - February 24, 2006 Proprietary Information
 CDU INTERROGATION (cont'd)
 • Input Monitoring Menu access and Features
 » allows monitoring of engine control input/output conditions in near real time
 » 7 sub-menus are available
  Control Loops
  Control Pressures
  Control Temperature
  Fuel System
  Oil System
  Engine Speed
  Discretes
 ENGINE 1 BITE TEST
 INPUT MONITORING 2/2
 < SPEEDS
 <DISCRETES
 <INDEX
 ENGINE 1 BITE TEST
 INPUT MONITORING 1/2
 < CONTROL LOOPS
 < CONTROL PRESSURES
 < CONTROL TEMPERATURES
 < FUEL SYSTEM
 < OIL SYSTEM
 < INDEX
 1/1
 HISTORY >
 < RECENT FAULTS
 < FAULT HISTORY
 < IDENT/CONFIG
 < GROUND TEST
 < INPUT MONITORING
 < INDEX
 ENGINE 1 BITE TEST
 MAIN MENU
 ENGINE 1 BITE TEST
 INPUT MONITORING
 ! ! ! NOTICE ! ! !
 THIS IS NOT AN APPROVED
 PRIMARY PROCEDURE USED
 TO ISOLATE FAULTS
 <GO BACK CONTINUE>
 52 CFM International CFM Product Support Engineering - February 24, 2006 Proprietary Information
 CDU INTERROGATION (cont'd)
 • Input Monitoring Sub-Menu access and Features (cont'd)
 » Control Pressures
  Display PO, PS3 and PT.
  Display PS13 and P25 (if PMUX installed).
 ENGINE 1 BITE TEST
 INPUT MONITORING 1/2
 < CONTROL LOOPS
 < CONTROL PRESSURES
 < CONTROL TEMPERATURES
 < FUEL SYSTEM
 < OIL SYSTEM
 < INDEX
 ENGINE 1 BITE TEST
 INPUT MONITORING
 PRESSURES - PSIA
 1/1
 < PO : P0.sx
 < PS13 : p13.fl
 < P25 : p25.fl
 < PS3 : ps3.sx
 < INDEX
 ENGINE 1 BITE TEST
 INPUT MONITORING
 PO SELECTION - PSIA
 1/1
 SEL P0 : 14.5
 P0 CH B : 14.4
 P0 CH A : 14.6
 PS ADIRU 1: 14.5
 PS ADIRU 2: 12.1
 ACT CH
 B<
 INDEX
 53 CFM International CFM Product Support Engineering - February 24, 2006 Proprietary Information
 ENGINE 1 BITE TEST
 INPUT MONITORING 1/2
 < CONTROL LOOPS
 < CONTROL PRESSURES
 < CONTROL TEMPERATURES
 < FUEL SYSTEM
 < OIL SYSTEM
 < INDEX
 ENGINE 1 BITE TEST
 INPUT MONITORING
 RTD TEMPERATURES - DEG C
 1/2
 < TAT : tat.sx
 < T25 : t25.sx
 < INDEX
 ENGINE 1 BITE TEST
 INPUT MONITORING
 T/C TEMPERATURES - DEGC2/2
 < T3 : t3.sx
 < TCC : tc.sx
 < T495 : t495.sx
 < T5 : t5.fl
 < INDEX
 ENGINE 1 BITE TEST
 INPUT MONITORING
 T495 SELECTION - DEG C
 1/1
 SEL T495 : 101
 T495S1 CH A: 102
 T495S2 CH A: 99
 T495S3 CH B: 572
 T495S4 CH B: 103
 ACT CH B
 < INDEX
 • Input Monitoring Sub-Menu access and Features (cont'd)
 » Control Temperatures
  Display TAT, T12, T25, T3, TCC and T49.5.
  Display T5 (if PMUX installed)
 CDU INTERROGATION (cont'd)
 54 CFM International CFM Product Support Engineering - February 24, 2006 Proprietary Information
 CDU INTERROGATION (cont'd)
 • Input Monitoring Sub-Menu access and Features (cont'd)
 » Fuel System Data Monitoring
  Display selected values of
  Fuel Flow (WFM)
  Fuel Metering Valve position (FMV)
  Fuel Filter Impending bypass Switch status
 ENGINE 1 BITE TEST
 INPUT MONITORING 1/2
 < CONTROL LOOPS
 < CONTROL PRESSURES
 < CONTROL TEMPERATURES
 < FUEL SYSTEM
 < OIL SYSTEM
 < INDEX
 ENGINE 1 BITE TEST
 INPUT MONITORING
 FUEL SYSTEM
 1/1
 FUEL FLOW: wfm.sx PPH
 FMV POS : fmv.sx %
 < FILTER BYPASSED : NO
 < INDEX
 ENGINE 1 BITE TEST
 INPUT MONITORING
 FUEL FILTER
 1/1
 SW 1 CH B: CLOSED
 SW 2 CH B: OPEN
 SW 1 CH A : CLOSED
 SW 2 CH A : OPEN
 ACT CH B
 < INDEX GMM CH A
 55 CFM International CFM Product Support Engineering - February 24, 2006 Proprietary Information
 CDU INTERROGATION (cont'd)
 • Input Monitoring Sub-Menu access and Features (cont'd)
 » Oil System Data Monitoring
  Display selected values of
  Oil Pressure (PEO)
  Oil Temperature (TEO)
  Oil Filter Impending bypass Switch status
  Debris Monitoring System Detector status (if DMS kit installed)
 ENGINE 1 BITE TEST
 INPUT MONITORING 1/2
 < CONTROL LOOPS
 < CONTROL PRESSURES
 < CONTROL TEMPERATURES
 < FUEL SYSTEM
 < OIL SYSTEM
 < INDEX
 ENGINE 1 BITE TEST
 INPUT MONITORING
 OIL SYSTEM
 FILTER BYPASSED : NO
 1/1
 FILTER INPUTS:
 SW 1 CH B: CLOSED
 SW 2 CH B: OPEN
 SW 1 CH A : CLOSED
 SW 2 CH A : OPEN
 ACT CH B
 < INDEX
 ENGINE 1 BITE TEST
 INPUT MONITORING
 OIL SYSTEM
 1/1
 < PEO : peo.sx PSIG
 < TEO : teo.sx C
 < FILTER BYPASSED: NO
 < DEBRIS DETECTED : NO
 ACT CH B
 < INDEX
 56 CFM International CFM Product Support Engineering - February 24, 2006 Proprietary Information
 GROUND TESTS
 • Ground test
 » used to support maintenance repair verification of engine LRUs
 » tests the entire engine control system with engine not running
 » selected from the flight compartment
 » 4 different Tests
  EEC Test
  T/R Lever Interlock Test
  Actuator Test
  Igniter Test
 57 CFM International CFM Product Support Engineering - February 24, 2006 Proprietary Information
 • EEC Test (FIM 73-00 Task 801) GROUND TESTS
 » control light checks
 » each channel performs
  EEC internal test
  engine sensors interface test
  engine electro-hydraulic interface test
 » detected faults displayed upon test completion
 Channel B
 EEC
 Channel A
 SPEED
 SENSORS
 TEMPERATURE
 SENSOR
 TORQUE MOTORS SOLENOIDS
 ELECTRO-HYDRAULIC
 EQUIPt
 PRESSURE
 SENSOR
 FMV SWITCHES
 RESOLVER
 POSITION
 SENSORS
 RVDTs
 LVDTs
 58 CFM International CFM Product Support Engineering - February 24, 2006 Proprietary Information
 GROUND TESTS
 • T/R Lever Interlock Test (AMM 73-21-00-700-805-F00 p501)
 » each channel tests the ability of the EEC
  to enable T/R Lever Interlock
  to disable T/R Lever Interlock
 » detected faults displayed upon completion of the test
 » WARNING: This test can cause the Reverser to move
 59 CFM International CFM Product Support Engineering - February 24, 2006 Proprietary Information
 GROUND TESTS
 • Actuator Test (AMM 71-00-00-700-807-F00 p501)
 » check the functionality of all hydraulic and electrical control loops
 » each channel
  cycles all control loops from Min to Max to Min positions
  monitor position sensors
  check command / feedback correllation
 » detected faults displayed upon completion of the test
 » WARNING: This test will cause the engine to turn
 Channel A
 Channel B
 EEC HMU VSV ACTUATORS
 FEEDBACK
 FEEDBACK
 COMMAND
 COMMAND
 60 CFM International CFM Product Support Engineering - February 24, 2006 Proprietary Information
 GROUND TESTS
 • Igniters Test (AMM 74-00-00-750-801-F00 p501)
 » check the functionality of the left or right igniter
 » each channel energizes the selected igniter
 » maintenance personnel
  listen for igniter arcing noise
 » detected faults displayed upon completion of the test
 61 CFM International CFM Product Support Engineering - February 24, 2006 Proprietary Information
 ACRONYMS AND ABBREVIATIONS
 • ADIRU: Air Data / Inertial Reference Unit
 • BTE: Built-In Test Equipment
 • BSV: Burner Staging Valve
 • CDS-DEU: Common Display System Display Electronic Unit
 • CDU: Control Display Unit
 • DFDAE: Digital Flight Data Acquisition Unit
 • EAU: Engine Accessory Unit
 • ECS: Environmental Control System
 • EEC: Electronic Engine Control
 • FADEC: Full Authority Digital Electronic engine Control
 • FMC: Flight Management Computer
 • FMV: Fuel Metering Valve
 • HMU: Hydro-Mechanical Unit
 • HPTACC: High Pressure Turbine Clearance Control
 • LPTACC: Low Pressure Turbine Clearance Control
 • LVDT: Linear Variable Differential Transformer
 • NVM: Non-Volatile Memory
 • RVDT: Rotary Variable Differential Transformer
 • TBV: Transient Bleed Valve
 • TLA: Thrust-Lever Resolver Angle
 • VBV: Variable Bleed Valve
 • VSV: Variable Stator Vane
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