Fadec full authority digital engine control-final

FADECFADEC

• What is FADEC?What is FADEC?• Digital Electronic ControlsDigital Electronic Controls• Design Requirements : Modern Design Requirements : Modern

Engine Control SystemEngine Control System• Why is FADEC Preferred? Why is FADEC Preferred? • A BackgrounderA Backgrounder• Location of FADECLocation of FADEC• Electronic Aspects of FADECElectronic Aspects of FADEC• How does FADEC work?How does FADEC work?• FADEC : FunctionsFADEC : Functions• FADEC : Essential Features FADEC : Essential Features • FADEC : Infrastructure (Simplified)FADEC : Infrastructure (Simplified)• Schematic DiagramSchematic Diagram• Advantages & LimitationsAdvantages & Limitations

FADECFADEC

WHAT IS FADEC?WHAT IS FADEC?

FADEC:FADEC: (Full Authority Digital Engine Control (Full Authority Digital Engine Control System)System)

- aa digital electronic control systemdigital electronic control system

- able to autonomously control the able to autonomously control the engine engine

- - throughout its whole operating throughout its whole operating range range

- - in both normal and fault conditionsin both normal and fault conditions


FADEC:FADEC: (Full Authority Digital Engine Control (Full Authority Digital Engine Control System)System)

- has a self-monitoring, self-operating, - has a self-monitoring, self-operating, redundant & fail-safe setupredundant & fail-safe setup

- - comprises of a digital computer comprises of a digital computer and the other accessories (that control and the other accessories (that control all the aspects of aircraft engine all the aspects of aircraft engine performance)performance)


FADEC:FADEC: (Full Authority Digital Engine Control System)(Full Authority Digital Engine Control System)

- key system of gas turbine engineskey system of gas turbine engines

- provides optimum engine provides optimum engine efficiency for a given flight conditionefficiency for a given flight condition

- also controls engine starting and also controls engine starting and restarting.restarting.



-- lowers the work-load of pilots, lowers the work-load of pilots,

-- reduces the occurrence of pilot reduces the occurrence of pilot errors,errors,

- provides for efficient engine provides for efficient engine operation.operation.



allows the manufacturer to allows the manufacturer to

-program -program engine limitations engine limitations and and

-receive engine health and -receive engine health and maintenance maintenance reports.reports.


-- no form of manual override no form of manual override availableavailable

-- places full authority to the control places full authority to the control of of operating parameters of the operating parameters of the engine in engine in the the hands of the hands of the computer. computer.

-- if a total FADEC failure occurs, the if a total FADEC failure occurs, the engine fails.engine fails.


Note:Note: If the engine is controlled If the engine is controlled digitally and digitally and electronically but allows electronically but allows for manual override, it is for manual override, it is considered considered solely an Electronic Engine Controlsolely an Electronic Engine Control (EEC)(EEC) or Electronic Control Unitor Electronic Control Unit (ECU). (ECU).

An EEC, though a component An EEC, though a component of a FADEC, of a FADEC, is not by itself FADEC. is not by itself FADEC. When standing alone, the When standing alone, the EEC makes EEC makes all of the decisions until the pilot all of the decisions until the pilot wishes to intervene.wishes to intervene.

DIGITAL ELECTRONIC CONTROLDIGITAL ELECTRONIC CONTROL

The benefits of digital electronic The benefits of digital electronic control of mechanical systems are control of mechanical systems are evident in greater precision and an evident in greater precision and an ability to measure or predict ability to measure or predict performance degradation and incipient performance degradation and incipient failure. failure.

Typical examples of this are digital Typical examples of this are digital implementations of flight control or fly-implementations of flight control or fly-by-wire by-wire (FBW)(FBW) and digital engine and digital engine control, or Full-Authority Digital Engine control, or Full-Authority Digital Engine Control Control (FADEC).(FADEC).

DIGITAL ELECTRONIC CONTROLDIGITAL ELECTRONIC CONTROL

Integrated Flight and Propulsion Integrated Flight and Propulsion Control Control (IFPC)(IFPC) allows closer integration allows closer integration of the aircraft flight control and engine of the aircraft flight control and engine control systems. control systems.

Flight control systems are virtually all Flight control systems are virtually all fly-by-wire fly-by-wire (FBW)(FBW) in the modern fighter in the modern fighter aircraft of today; the benefits being aircraft of today; the benefits being weight reduction and improved weight reduction and improved handling characteristics. handling characteristics.

DESIGN REQUIREMENTS OF DESIGN REQUIREMENTS OF MODERN ENGINE CONTROL MODERN ENGINE CONTROL

SYSTEMSYSTEM

• Speed / Accuracy / Ease of Control Speed / Accuracy / Ease of Control

(Least Aircrew Workloads)(Least Aircrew Workloads)

• Wide Operational Range Wide Operational Range

• Reliability & Operational SafetyReliability & Operational Safety

• Low Operating & Maintenance CostsLow Operating & Maintenance Costs

• Should Not Add WeightShould Not Add Weight

• Fuel EfficiencyFuel Efficiency

• Dependable StartsDependable Starts

WHY IS FADEC PREFERRED?WHY IS FADEC PREFERRED?

New engines are adopting FADEC for New engines are adopting FADEC for

-the benefits offered by digital -the benefits offered by digital control, control,

-improved reliability and -improved reliability and performance, performance,

-weight-reduction and -weight-reduction and

-other improvements in system -other improvements in system integration and integration and data flow.data flow.

A BACKGROUNDERA BACKGROUNDER

The FADEC systems were first used in The FADEC systems were first used in the automotive Industry where it is the automotive Industry where it is well proven.well proven.

Now-a-days airlines and the militaries Now-a-days airlines and the militaries all over the world incorporate it on all over the world incorporate it on turbine powered aircraft.turbine powered aircraft.

FADECs are made for piston engine FADECs are made for piston engine and jet engines both but they differ in and jet engines both but they differ in the way of controlling the engine .the way of controlling the engine .


Advanced, intelligent & robust Advanced, intelligent & robust propulsion controls are critical for propulsion controls are critical for improving the safety and improving the safety and maintainability of future propulsion maintainability of future propulsion systems. systems.

Propulsion system reliability is Propulsion system reliability is considered to be critical for aircraft considered to be critical for aircraft survival. Hence, FADEC systems came survival. Hence, FADEC systems came into being.into being.


FADEC is now common on many engines.FADEC is now common on many engines.

Semiconductor and equipment cooling Semiconductor and equipment cooling technology has advanced so that control technology has advanced so that control units can now be mounted on the engine units can now be mounted on the engine and still provide highly reliable operation and still provide highly reliable operation for long periods. for long periods.


Developing and implementing modern Developing and implementing modern intelligent engine systems requires intelligent engine systems requires the introduction of numerous sensors, the introduction of numerous sensors, actuators and processors to provide actuators and processors to provide the advanced functionality. the advanced functionality.


The application of artificial The application of artificial

intelligence and knowledge-intelligence and knowledge-based system for both software based system for both software and hardware provides the and hardware provides the foundation for building the foundation for building the intelligent control system of the intelligent control system of the future.future.


With time, control systems became With time, control systems became

more sophisticated with the more sophisticated with the introduction of additional engine introduction of additional engine condition sensors and multiple condition sensors and multiple servo-loops. servo-loops.


The task of handling engines was The task of handling engines was eased by the introduction of eased by the introduction of electronic control in the form of electronic control in the form of magnetic amplifiers in early civil and magnetic amplifiers in early civil and military aircraft.military aircraft.


The magnetic amplifiers allowed The magnetic amplifiers allowed engines to be stabilized at any speed engines to be stabilized at any speed in the throttle range by introducing a in the throttle range by introducing a servo-loop with engine exhaust gas servo-loop with engine exhaust gas temperature as a measure of engine temperature as a measure of engine speed and an analogue fuel valve to speed and an analogue fuel valve to control fuel flow. control fuel flow.


Transistors, integrated circuits and Transistors, integrated circuits and high temperature semi-conductors high temperature semi-conductors have all played a part in the evolution have all played a part in the evolution of control systems from range of control systems from range temperature control through to full temperature control through to full digital engine control systems.digital engine control systems.


This allowed the pilot to accelerate This allowed the pilot to accelerate and decelerate the engine while the and decelerate the engine while the control system limited fuel flows to control system limited fuel flows to prevent over- speeds or excessive prevent over- speeds or excessive temperatures.temperatures.


With modern FADEC systems there With modern FADEC systems there are no mechanical control rods or are no mechanical control rods or mechanical reversions, and the pilot mechanical reversions, and the pilot can perform carefree handling of the can perform carefree handling of the engine throughout the flight engine throughout the flight envelope.envelope.


On modern aircraft the engine is On modern aircraft the engine is supervised by a computer to allow supervised by a computer to allow the pilot to operate at maximum the pilot to operate at maximum performance in a combat aircraft or performance in a combat aircraft or at optimum fuel economy in a at optimum fuel economy in a passenger carrying aircraft.passenger carrying aircraft.


Today, each FADEC is unique and Today, each FADEC is unique and therefore is expensive to develop, therefore is expensive to develop, produce, maintain, and upgrade for produce, maintain, and upgrade for its particular application. its particular application.


In the future, it is desired to establish In the future, it is desired to establish a universal or common standard for a universal or common standard for engine controls and accessories. This engine controls and accessories. This will significantly reduce the high will significantly reduce the high development and support costs development and support costs across platforms.across platforms.

LOCATION OF FADECLOCATION OF FADEC

FADEC is normally located on the FADEC is normally located on the engine fan casing. Therefore, FADEC engine fan casing. Therefore, FADEC cooling is difficult.cooling is difficult.

LOCATION OF FADECLOCATION OF FADEC

However, there are many features of However, there are many features of engine control which are distributed engine control which are distributed around the engine – such as reverse around the engine – such as reverse thrust, presently pneumatically thrust, presently pneumatically actuated – which would need to be actuated – which would need to be actuated by alternative means in a actuated by alternative means in a more-electric engine. This leads to the more-electric engine. This leads to the possibility of using distributed engine possibility of using distributed engine control.control.

ELECTRONIC ASPECTS OF FADECELECTRONIC ASPECTS OF FADEC

Modern ECUs use a microprocessor Modern ECUs use a microprocessor which can process the inputs from the which can process the inputs from the engine sensors in real time. An engine sensors in real time. An electronic control unit contains the electronic control unit contains the hardware and software (firmware). hardware and software (firmware).

ELECTRONIC ASPECTS: FADECELECTRONIC ASPECTS: FADEC

The hardware consists of electronic The hardware consists of electronic components on a printed circuit components on a printed circuit board (PCB), ceramic substrate or a board (PCB), ceramic substrate or a thin laminate substrate. The main thin laminate substrate. The main component on this circuit board is a component on this circuit board is a microcontroller chip (CPU). microcontroller chip (CPU).

ELECTRONIC ASPECTS : FADECELECTRONIC ASPECTS : FADEC

The software is stored in the The software is stored in the microcontroller or other chips on the microcontroller or other chips on the PCB, typically in EPROMs or flash PCB, typically in EPROMs or flash memory so the CPU can be re-memory so the CPU can be re-programmed by uploading updated programmed by uploading updated code or replacing chips. This is also code or replacing chips. This is also referred to as an Electronic Engine referred to as an Electronic Engine Management System (EMS).Management System (EMS).

HOW DOES FADEC WORK?HOW DOES FADEC WORK?

FADEC works by receiving multiple FADEC works by receiving multiple input variables of the current flight input variables of the current flight condition including air density, throttle condition including air density, throttle lever position, engine temperatures, lever position, engine temperatures, engine pressures, and many others.engine pressures, and many others.


Each FADEC is essentially a centralized Each FADEC is essentially a centralized system, with a redundant, central system, with a redundant, central computer and centrally located analog computer and centrally located analog signal interfacing circuitry for signal interfacing circuitry for interfacing with sensors and actuators interfacing with sensors and actuators located throughout the propulsion located throughout the propulsion system. system.

Engine operating parameters such as Engine operating parameters such as fuel flow, stator vane position, bleed fuel flow, stator vane position, bleed valve position and others are valve position and others are computed from this data and applied computed from this data and applied as appropriate.as appropriate.


For example, to avoid exceeding a For example, to avoid exceeding a certain engine temperature, the certain engine temperature, the FADEC can be programmed to FADEC can be programmed to automatically take the necessary automatically take the necessary measures without pilot intervention.measures without pilot intervention.

The inputs are received by the EEC The inputs are received by the EEC and analyzed up to 70 times per and analyzed up to 70 times per second.second.



FADEC computes the appropriate thrust FADEC computes the appropriate thrust settings and applies them. settings and applies them.

During flight, small changes in During flight, small changes in operation are constantly being made to operation are constantly being made to maintain efficiency. maintain efficiency.

Maximum thrust is available for Maximum thrust is available for emergency situations if the throttle is emergency situations if the throttle is advanced to full, but remember, advanced to full, but remember, limitations can’t be exceeded.limitations can’t be exceeded.


Another new feature of the FADEC Another new feature of the FADEC system is the ability to record the last system is the ability to record the last 900 hours of flight. 900 hours of flight.

With readings taken every second, this With readings taken every second, this stored information can be used to stored information can be used to diagnose problem areas as well as diagnose problem areas as well as review recent flight history.review recent flight history.

FADEC : FUNCTIONSFADEC : FUNCTIONS

ENGINE CONTROLENGINE CONTROL

ACQUIREACQUIRESENSOR DATASENSOR DATA

PROCESSPROCESSCONTROL LAWSCONTROL LAWS

COMMANDCOMMANDACTUATORSACTUATORS

AIRFRAMEAIRFRAMECOMMUNICATIONCOMMUNICATION

REPORT REPORT ENGINE STATUSENGINE STATUS

RECEIVE ENGINERECEIVE ENGINEPOWER COMMANDPOWER COMMAND

ENGINEENGINE HEALTHHEALTHMONITORINGMONITORING

DIAGNOSTICDIAGNOSTIC

PROGNOSTICPROGNOSTIC

ADAPTIVEADAPTIVE

FADECFADEC

FADEC : ESSENTIAL FADEC : ESSENTIAL FEATURESFEATURES

- Control & Monitoring of Engine Operations

- Dual Channels & Redundancy

- Engine Life Monitoring

- Record of Engine Performance Parameters

- Automated Troubleshooting

- Memory Read or Recall of Engine Data

- Control of Common Engine Problems

- Display of Warnings

- Adaptation

- Isochronous Idle Speed

FADEC :INFRASTRUCTURFADEC :INFRASTRUCTUREE

CONTROL OPERATIONS IN GAS TURBINE ENGINESCONTROL OPERATIONS IN GAS TURBINE ENGINES

FADEC: INFRASTRUCTUREFADEC: INFRASTRUCTURE

CONTROL OPERATIONS IN GAS TURBINE ENGINES- Air Control (Compressor Entry)

- Fuel Control (Main / AB / Starting System)

- Starting & Ignition Control

- Lubrication Control

- Surge Control (Through Bleed Valve)

- Thrust Control (Through Exhaust Nozzle)

- Vibration Control (Through Air / Fuel Control)


SAMPLE CHAIN OF CONTROL (MECH.) OPERATIONSAMPLE CHAIN OF CONTROL (MECH.) OPERATION

FADEC COMPUTERFADEC COMPUTER

GEAR DRIVENGEAR DRIVENMECHANICAL PUMPMECHANICAL PUMP

ELECTRO-HYDRO-MECHNICAL ELECTRO-HYDRO-MECHNICAL CONTROL UNITCONTROL UNIT

ACTUATEDACTUATEDASSEMBLYASSEMBLY

SOLENOIDSOLENOIDVALVESVALVES

SERVOSERVOACTUATINGACTUATING

MOTORSMOTORS

WORKING FLUID WORKING FLUID FROMFROM

ENGINE / AIRCRAFTENGINE / AIRCRAFT

AIRCRAFT COMPUTERAIRCRAFT COMPUTER COCKPITCOCKPIT

POSITIONPOSITIONSENSORSSENSORS

MECHANICALMECHANICALACTUATORSACTUATORS

POSITIONPOSITIONSENSOR-1SENSOR-1

POSITIONPOSITIONSENSOR-2SENSOR-2

FADEC : INFRASTRUCTUREFADEC : INFRASTRUCTURE

SAMPLE CHAIN OF CONTROL (ELECT.) OPERATIONSAMPLE CHAIN OF CONTROL (ELECT.) OPERATION

ELECTRO-HYDRO-MECHNICAL ELECTRO-HYDRO-MECHNICAL CONTROL UNITCONTROL UNIT POSITIONPOSITION

SENSOR-1SENSOR-1SOLENOIDSOLENOIDVALVESVALVES

SERVOSERVOACTUATINGACTUATING

MOTORSMOTORS

POSITIONPOSITIONSENSOR-2SENSOR-2POSITIONPOSITION

SENSORSSENSORS

MECHANICALMECHANICALACTUATORSACTUATORS

FADECFADECCOMPUTERCOMPUTER

POWERPOWERSUPPLYSUPPLY

VARIOUS INPUTS VARIOUS INPUTS FROM AIRCRAFTFROM AIRCRAFT

DISPLAY PANELDISPLAY PANELIN COCKPITIN COCKPIT

PILOT’s THROTTLEPILOT’s THROTTLEIN COCKPITIN COCKPIT

VARIOUS INPUTS FROM / VARIOUS INPUTS FROM / COMMANDS TO ENGINECOMMANDS TO ENGINE


HARDWARE:HARDWARE:

- Dual Power SupplyDual Power Supply-- FADEC Computer (With Logic Circuit PCBs & FADEC Computer (With Logic Circuit PCBs &

Programmed / Programmable Memory)Programmed / Programmable Memory)- A Set of Servo Actuating Motors / Solenoid Valves / A Set of Servo Actuating Motors / Solenoid Valves /

Position Sensors (for every System Control Unit)Position Sensors (for every System Control Unit)- Dual Position Sensors for Actuators (of every Dual Position Sensors for Actuators (of every

System) System) - A Set of Electrical Harnesses (for every System) A Set of Electrical Harnesses (for every System) - Display Panel with Indicators / Warning Lights (in Display Panel with Indicators / Warning Lights (in

Cockpit)Cockpit)- Multiple Engine RPM, Pressure Sensors & Multiple Engine RPM, Pressure Sensors &

ThermocouplesThermocouples- Pilot’s ThrottlePilot’s Throttle

FADEC : INFRASTRUCTUREFADEC : INFRASTRUCTURESOFTWARE:SOFTWARE:

- EPR Schedules (For Thrust, over Entire Range of Engine Operation Without FADEC Computer Failure)

- N Schedules (For Thrust as per Pilot’s Throttle, Engine Operation in case of Limited FADEC Computer Functionality)

Note: In case of certain degree of FADEC failure, there is an automatic mode switch-over from EPR to N rating. However, if the failure disappears, the pilot can reset the mode to switch-back to EPR mode.


INPUTS:INPUTS:

From Aircraft.From Aircraft.

- Ambient TemperatureAmbient Temperature- AltitudeAltitude- Mach NumberMach Number- Angle of AttackAngle of Attack- Impact PressureImpact Pressure- Landing Gear Position Landing Gear Position - Missile / Rocket Firing Signals etc.Missile / Rocket Firing Signals etc.


INPUTS:INPUTS:

From Engine.From Engine.

- Throttle Lever Position Throttle Lever Position - RPMRPM- Turbine Outlet / Exhaust Gas Turbine Outlet / Exhaust Gas

TemperatureTemperature- Exhaust Nozzle AreaExhaust Nozzle Area- Fan Duct Flaps PositionFan Duct Flaps Position- Bearing TemperaturesBearing Temperatures- Engine VibrationEngine Vibration- Engine PressuresEngine Pressures


SIMPLIFIED FADEC ARCHITECTURESIMPLIFIED FADEC ARCHITECTURE

FADECFADECLANE-ALANE-A

MONITORMONITORFADECFADECLANE-ALANE-A

CONTROLCONTROL

FADECFADECLANE-BLANE-B

MONITORMONITORFADECFADECLANE-BLANE-B

CONTROLCONTROL

FADEC LANE-AFADEC LANE-A

FADEC LANE-BFADEC LANE-BENGINEENGINETHRUSTTHRUSTDEMANDDEMAND

ENGINEENGINEFUELFUEL

DEMANDDEMAND


SIMPLIFIED FADEC ARCHITECHTURESIMPLIFIED FADEC ARCHITECHTURE

This simplified architecture is typical This simplified architecture is typical of of many dual-channel FADECs. many dual-channel FADECs.

There are two independent lanes: There are two independent lanes: Lane A Lane A and Lane B. and Lane B.



Each lane comprises a Command Each lane comprises a Command and Monitor portion, which are and Monitor portion, which are interconnected for cross monitoring interconnected for cross monitoring purposes, and undertakes the task purposes, and undertakes the task of metering the fuel flow to the of metering the fuel flow to the engine in accordance with the engine in accordance with the necessary control laws to satisfy the necessary control laws to satisfy the flight crew thrust command.flight crew thrust command.



The analysis required to decide The analysis required to decide upon the impact of certain failures upon the impact of certain failures in conjunction with others, in conjunction with others, requires a Markov model in order requires a Markov model in order to be able to understand the to be able to understand the dependencies.dependencies.


MARKOV ANALYSIS MODELMARKOV ANALYSIS MODEL

•By using this model the effects of By using this model the effects of interrelated failures can be interrelated failures can be examined. examined.

•The model has a total of 16 states The model has a total of 16 states as shown by the number in the as shown by the number in the bottom right-hand corner of the bottom right-hand corner of the appropriate box.appropriate box.



•Each box relates to the serviceability Each box relates to the serviceability state of the Lane A Command (Ca) and state of the Lane A Command (Ca) and Monitor (Ma) channels and Lane B Monitor (Ma) channels and Lane B Command (Cb) and Monitor (Mb) Command (Cb) and Monitor (Mb) channels. channels.



•These range from the fully serviceable These range from the fully serviceable state in box 1 through a series of failure state in box 1 through a series of failure conditions to the totally failed state in conditions to the totally failed state in box 16. box 16.

•Clearly most normal operating Clearly most normal operating conditions are going to be in the left-conditions are going to be in the left-hand region of the model.hand region of the model.

FADEC : FADEC : INFRASTRUCTUREINFRASTRUCTURE

MARKOV MODEL ANALYSISMARKOV MODEL ANALYSIS

CaMa.CbMb 1CaMa.CbMb 1

CaMa.CaMa.CbCbMb 4Mb 4

CaCaMa.CbMb 2Ma.CbMb 2

CaCaMaMa.CbMb 3.CbMb 3

CaMa.CbCaMa.CbMbMb 5 5

CaCaMa.Ma.CbMbCbMb 14 14

CaMaCaMa..CbCbMb 12Mb 12

CaMaCaMa.Cb.CbMbMb 13 13

CaCaMaMa..CbMbCbMb 15 15

CaMaCaMa..CbMbCbMb 16 16

CaCaMa.CbMa.CbMbMb 8 8

CaMaCaMa.CbMb 6.CbMb 6

CaCaMa.Ma.CbCbMb 7Mb 7

CaCaMaMa..CbCbMb 9Mb 9

CaCaMaMa.Cb.CbMbMb 10 10

CaMa.CaMa.CbMbCbMb 11 11

CONTROLLABLECONTROLLABLEENGINEENGINE

DISPACHABLEDISPACHABLEENGINEENGINE

ENGINEENGINESHUT-DOWNSHUT-DOWN

NO FAILURE 1 FAILURE 2 FAILURES 3 FAILURES 4 NO FAILURE 1 FAILURE 2 FAILURES 3 FAILURES 4 FAILURESFAILURES

FADEC: FADEC: INFRASTRUCTUREINFRASTRUCTURE

Concentrating on the left-hand side of the Concentrating on the left-hand side of the model it can be seen that the fully serviceable model it can be seen that the fully serviceable state in box 1 can migrate to any one of six state in box 1 can migrate to any one of six states:states:

– Failure of Command channel A results in Failure of Command channel A results in state 2 being reached.state 2 being reached.

– Failure of Monitor channel A results in state Failure of Monitor channel A results in state 3 being reached.3 being reached.

– Failure of Command channel B results in Failure of Command channel B results in state 4 being reached.state 4 being reached.

– Failure of Monitor channel B results in state Failure of Monitor channel B results in state 5 being reached.5 being reached.

– Failure of the cross-monitor between Failure of the cross-monitor between Command A and Monitor A results in both Command A and Monitor A results in both being lost simultaneously and reaching being lost simultaneously and reaching state 6.state 6.

– Failure of the cross-monitor between Failure of the cross-monitor between Command B and Monitor B results in both Command B and Monitor B results in both being lost simultaneously and reaching being lost simultaneously and reaching state 11.state 11.


All of these failure states result in an All of these failure states result in an engine which may still be controlled by engine which may still be controlled by the FADEC. However, further failures the FADEC. However, further failures beyond this point may result in an beyond this point may result in an engine which may not be controllable engine which may not be controllable either because both control channels either because both control channels are inoperative or because the ‘good’ are inoperative or because the ‘good’ control and monitor lanes are in control and monitor lanes are in opposing channels or worse. opposing channels or worse.


The model shown above is constructed The model shown above is constructed according to the following rules: an according to the following rules: an engine may be dispatched as a ‘get-engine may be dispatched as a ‘get-you-home’ measure provided that only you-home’ measure provided that only one monitor channel has failed. one monitor channel has failed.

This means that states 3 and 5 are This means that states 3 and 5 are dispatchable: but not states 2, 4, 6, or dispatchable: but not states 2, 4, 6, or 11 as subsequent failures could result 11 as subsequent failures could result in engine shut-down.in engine shut-down.

FADEC: ESSENTIAL FADEC: ESSENTIAL FEATURESFEATURES

MILITARY / TRANSPORT AIRCRAFTMILITARY / TRANSPORT AIRCRAFT-- Compressor Entry Guide Vanes Control Compressor Entry Guide Vanes Control

(For LP Compressor & HP Compressor)(For LP Compressor & HP Compressor)-- Main Fuel ControlMain Fuel Control- AB Fuel Control (For Core & Fan AB) AB Fuel Control (For Core & Fan AB) - Starting Fuel Control & Ignition Starting Fuel Control & Ignition

ControlControl- Bleed Valve Control & Fan Duct Flaps Bleed Valve Control & Fan Duct Flaps

ControlControl- Exhaust Nozzle Control Exhaust Nozzle Control - Lubrication Control & Vibration ControlLubrication Control & Vibration Control

FADEC : SCHEMATIC DIAGRAMFADEC : SCHEMATIC DIAGRAM

AIRCRAFTAIRCRAFTCOMPUTERCOMPUTER

PILOTPILOTININ

COCKPITCOCKPIT

MAIN FUELMAIN FUELCONTROLCONTROL

CORE AB FUELCORE AB FUELCONTROLCONTROL

STARTINGSTARTING&&

IGNITIONIGNITIONCONTROLCONTROL

FAN AB FUELFAN AB FUELCONTROLCONTROL

EXHAUST NOZZLEEXHAUST NOZZLECONTROLCONTROL

FAN DUCT FLAPSFAN DUCT FLAPSCONTROLCONTROL

BLEED VALVEBLEED VALVECONTROLCONTROL

LP COMPRESSORLP COMPRESSORAIR EGV CONTROLAIR EGV CONTROL

HP COMPRESSORHP COMPRESSORAIR EGV CONTROLAIR EGV CONTROL

FADECFADECEECUEECU

POWERPOWERSUPPLYSUPPLY

CPU /Memory

Actuationelectronics

Sensorelectronics

Sensorelectronics


Sensorelectronics


Actuator_1

Sensor_1

Sensor_ j

Actuator_n

Sensor_2

Actuator_2

Communication

Power

BU

S

FADEC

Centralized Engine Control

Communication

CENTRALIZED CONTROL ARCHITECTURECENTRALIZED CONTROL ARCHITECTURE Each function resides within the FADEC and uses unique point-to-Each function resides within the FADEC and uses unique point-to-point analog connections to system effectors.point analog connections to system effectors.

CPU /Memory


Sensorelectronics

Sensorelectronics


Sensorelectronics


Actuator_1

Sensor_1

Sensor_ j

Actuator_n

Sensor_2

Actuator_2

Communication

Power

BU

S

FADEC

Centralized Engine Control

Communication

DISTRIBUTED CONTROL ARCHITECTUREDISTRIBUTED CONTROL ARCHITECTURE Functions are distributed outside of the FADEC and communicate Functions are distributed outside of the FADEC and communicate via a common interface standard.via a common interface standard.

FADEC : ADVANTAGESFADEC : ADVANTAGES

-- Reduced Aircrew Workload.Reduced Aircrew Workload.- Improved Fuel Efficiency up to Improved Fuel Efficiency up to

15% (Due to faster, Accurate 15% (Due to faster, Accurate Engine Control no trimming is Engine Control no trimming is required).required).

- Reduced Aircraft Weight and Reduced Aircraft Weight and Engine Size (Due to Absence of Engine Size (Due to Absence of Heavy Mechanical Assemblies, Heavy Mechanical Assemblies, No Scattering of Pipelines & No Scattering of Pipelines & Electrical Wirings).Electrical Wirings).

- Enhanced Engine Life (Due to Enhanced Engine Life (Due to Engine Operation in Safer / Mean Engine Operation in Safer / Mean Range). Range).

- Improved Reliability (Due to Improved Reliability (Due to Redundancy and Dual Channel).Redundancy and Dual Channel).


- Minimum Maintenance due to On Minimum Maintenance due to On

Board Computer Guided Board Computer Guided Troubleshooting (Aircraft Troubleshooting (Aircraft can return to Flying at the can return to Flying at the Earliest).Earliest).

- Isochronous Idle speed leads to Isochronous Idle speed leads to Smoother Engine Starts. Smoother Engine Starts.


-- Maximum Performance in a combat Maximum Performance in a combat aircraft or at Optimum Fuel aircraft or at Optimum Fuel Economy in a Transport Aircraft are Economy in a Transport Aircraft are possible after necessary possible after necessary Adaptation / Programming of Adaptation / Programming of FADEC Computer. FADEC Computer.

-- Auto-testing removes the need for Auto-testing removes the need for test-running the engine after minor test-running the engine after minor maintenance work ( Resulting in maintenance work ( Resulting in annual savings of millions of gallon annual savings of millions of gallon of fuel for the fleet.of fuel for the fleet.

FADEC : LIMITATIONSFADEC : LIMITATIONS

- Pilot can not override the FADEC Control.

- In the event of complete FADEC Failure, pilot left with no other option than having to fly with least performance, just sufficient to land safely. (This limitation has been removed in modern transport aircraft by having two FADEC Computers.)

FADEC: ANY QUESTIONFADEC: ANY QUESTION

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Fadec full authority digital engine control-final

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