Integrated Modular Avionics (IMA) - PDF

Here is the converted markdown format of the attached document. # Aviation Australia ## TOPIC 13.20: INTEGRATED MODULAR AVIONICS ### History of Integrated Modular Avionics (IMA) Some believe the Integrated Modular Avionics (IMA) concept originated in the United States with the new F-22 and F-35 fi...

Here is the converted markdown format of the attached document. # Aviation Australia ## TOPIC 13.20: INTEGRATED MODULAR AVIONICS ### History of Integrated Modular Avionics (IMA) Some believe the Integrated Modular Avionics (IMA) concept originated in the United States with the new F-22 and F-35 fighters and then migrated to the commercial jetliner arena. Others say the modular avionics concept, with less integration, has been used in business jets and regional airliners since the late 1980s or early 90s. However regardless of where it began, using the IMA approach it was able to shave 2,000 pounds off the avionics suite of the new 787 Dreamliner, versus previous comparable aircraft. For Airbus the IMA concept cuts in half the part numbers of processor units for the new A380 avionics suite. ### Advantages of IMA Concept As a consequence, IMA concept reduces the maintenance cost and increases the reliability due to a smaller number of computers. * IMA is the trend of the future due to the economies in fuel savings and increases the payload factor derived from less weight. * It reduces workload for flight crew and maintenance personnel due to less operational activities. * Multiple functions can be achieved with single LRU. The image illustrates the difference between conventional avionics and integrated modular avionics(IMA). In conventional avionics each function (A, B, C) has its own Line Replaceable Unit (LRU). In Integrated Modular Avionics all Functions, (A, B, C) are within a single module. **Figure 1: IMA concept** ### Typical IMA Architecture Thanks to the new avionics concept Integrated Modular Avionics (IMA), most of the conventional avionics Line Replacement Units (LRU) functions are combined in modular structure. On Embraer 170/190 each IMA is a metal cabinet solidly grounded to the aircraft frame. This cabinet is called the Modular Avionics Unit (MAU) and it contains different line replaceable modules (LRM) and can be single or dual channel. Each MAU channel has a power supply module, Network Interface Controller (NIC), MAU data communications back plane, and other modules connected to that back plane. **Figure 2: Modular avionics unit (EMB170/190)** There is an image of a modular avionics unit, with components labelled, placed inside of a metal frame. The MAUs incorporate new hardware and software technologies, host independent applications in the same computing and memory resource, and also supply an input/output interface service to some of the conventional avionics. The MAUs usually have Digital Engine Operating System (DEOS) compliant processing, Input/Output (I/O), and Network Interface Modules (NIM). The MAUs transmit and receive data through the Avionics Standard-Communication Bus (ASCB) and LAN buses. The generic I/O, custom I/O (CSIO), control I/O (CIO), and other modules input the sensor and system data to the processor modules that calculate the data to control and monitor the aircraft. The MAU cabinet only connects to the aircraft system wiring through the front connectors on the Line Replaceable Modules (LRM). For security reason, firewalls protect the MAUs from malicious data coming from other common applications. The image displays is a diagram illustrating how a single unit handles different systems,labelled Application A, B, and C and LRU A, B, and C. **Figure 3: Single unit handles different systems** The MAUs use following bus data, networks and components for data processing and MAU operations: * Avionics Standard-Communication Bus (ASCB) * Network Interface Controller (NIC) * Local Area Network (LAN) * Controller Area Network (CAN) data bus * Back plane * ASCB Coupler * ASCB Terminators ### The Avionics Standard-Communication Bus (ASCB) The Avionics Standard-Communication Bus (ASCB) is the primary communications path between the major subsystems of the avionics systems. It is a high-speed, serial data bus network made up of four data buses: * Left primary * Right primary * Left backup * Right backup Data on the ASCB is transmitted in data frames at 12.5 millisecond (ms) intervals (80 Hz). The data frame is divided into blocks or time slots. Each user of the bus transmits in an assigned time slot called "synchronisation pulse". Each bus uses a single shielded twisted pair of wires (data buses) with resistor terminations. The bus couplers isolate the ASCB buses from each other to prevent a short circuit on one bus from having an effect on the other buses. **Figure 4: Avionics Standard Communication Bus (ASCB)** The figure is a diagram of the Avionics Standard Communication Bus (ASCB). It shows aircraft systems connected a network of MAUs. ### Network Interface Controller (NIC) Communication in the MAU is managed by the NIC. The NIC transmits and receives ASCB and LAN data and makes this data available to other modules in the MAU. ASCB data transmission timing is controlled by the NIC in each LRU and is synchronised across each bus by a master Network Interface Controller. Each NIC keeps time synchronisation by correcting its internal clock with the synchronisation pulses. By doing this, each NIC determines when to transmit its data in the ASCB frame. Each NIC attached to the ASCB is related to one side (right or left) and connected to three buses: * Onside primary * Onside backup * Cross-side primary ### Local Area Network (LAN) The NIC controls data transmission on the Local Area Network (LAN) bus. This serial data bus is physically and electrically separate from the ASCB. The LAN is used for development, maintenance, and software loading. It supplies an additional communication path to be used between the display units, the MAU and peripheral items such as the printer and the Data-Loader. The LAN is a thin coaxial cable, which is Ethernet-based and uses the Transfer Control Protocol/Internet Protocol (TCP/IP). This protocol makes it possible for peripheral computers/communications devices to interface with the NIC over the LAN. **Figure 5: Data buses** The data buses diagram includes elements such as I/O Client NO.1, Processor Client NO.1, Special Purpose Client, BIC FRAME BUFFER, BACKPLANE BUS, Network Interface Controller, LAN and ASCB. ### Controller Area Network (CAN) Data Bus The Controller Area Network (CAN) bus is based on the CAN industry standard and uses controller integrated circuits that operate at 500 kHz. The CAN bus is bidirectional and uses the same wire and harness construction as the ASCB. The CAN consists of multi-point serial synchronous digital communications. ### Backplane Units in the system use the back-plane network to send data between each other. The backplane network contains the ASCB, LAN, and Direct Current (DC) power buses. Connection to the backplane is supplied by a standard hardware interface called the Backplane Interface Controller (BIC). The BIC is installed on the MAU modules. The BIC stores and sends received ASCB and LAN data from the NIC to the modules in sequence when the modules are prepared to receive the data. **Figure 6: Backplane** The back plane diagram includes MAU, AIOP, GENERIC I/0, ASCB, NIC/PROC, ARINC 429 and BACKPLANE BUS. ### ASCB Coupler The ASCB bus coupler isolates onside primary, onside backup, and cross-side primary buses. It uses a transformer coupler for isolation. The transformer coupler is impedance - matched to both the ASCB and the MAU. **Figure 7: ASCB Coupler** The image is a picture of an ASCB Coupler. ### ASCB Terminators The ASCB terminators are devices attached to the endpoints of each ASCB with the purpose of absorbing signals so that they do not reflect back down the line. ASCB TERMINATOR **Figure 8: ASCB terminator** The image shows the ASCB terminator inside LAN connector compartment. ### Operation of MAU The MAUs are important Line Replaceable Units (LRU) in the system because they hold the avionics processors and utility functions. The MAUs send data to and from each other on the ASCB and LAN buses. Communication in the MAU is managed by the NIC. The NIC sends and receives ASCB and LAN data and makes this data available to client modules within the MAU through a backplane. The client modules may be processor modules, Input/Output (I/O) modules, memory modules, or other hybrid modules. NIC modules have Aircraft Personality Modules (APM) installed in their back shells. Aircraft Personality Modules (APM) are programmed with system identification data, options data, system settings data, and rigging data. The data content is custom for the aircraft. ### Typical IMA Version of Flight Guidance System (E170/190) In general, the following contrast will help you to understand the difference between IMA version of Autoflight Control System (AFCS) and conventional Autoflight Control System. The additional feature in the new IMA AFCS is it contains Actuator Input-Output Processors (AIOP) as Line Replaceable Modules (LRM). Typically, four Actuator Input-Output Processor (AIOP) modules are installed in the MAU on Embraer 170/190. **Figure 9: Flight guidance system (EMB 170/190)**. The Flight Guidance System Diagram includes the systems as VHF NAV, FMS, IRS, Air Data System, Radar Altimeter, Yaw damper/Turn coordination, flight director, automatic pilot, automatic pitch trim/mach trim, and flight control system The AIOP modules also connect to other avionic and flight control equipment and systems, as appropriate and necessary for the AIOP function. Two AIOP modules operate in each channel. These modules are identified as lane A and lane B. The modules in these two lanes have the same software, but do separate, complementary, and similar functions that depend on the lane. The AIOP modules in lane A and lane B must operate at the same time for the servos in that channel to be active and engaged. The AIOP modules on the MAUs are connected to the autopilot servo via Controller Area Network (CAN) bus. The Actuator Input/Output Processor (AIOP) modules do all of the necessary computations and data processing for the Autopilot and Yaw Damper (YD) functions. The AIOP modules collect the necessary data via Avionics Standard-Communication Bus (ASCB) from other Flight Guidance Control System (FGCS) data inputs for calculations. The AIOP modules send position data to the servos through a bidirectional CAN data bus. This CAN bus is the interface between the Flight Control Module (FCM) of each MAU and the Primary Actuator Control Electronics (P-ACE). The P-ACE sends commands to the relevant control actuators to activate the automatic flight control function. **Figure 10: IMA version of AFCS**. The diagram shows is an IMA version of the Automatic Flight Control System, with components such as control yoke, aileron, MAU's, AIOPS, RUDDER PEDALS, LVDT ,FCMS ,P-ACES, Aileron Servo ,Actuator, Elevator Servo ,and Actuator. ### Types of IMA The types of IMAs depend on the aircraft type and its systems. Within a given type, all IMAs are interchangeable but may require a software reconfiguration. Each type hosts avionics applications. For example, on B787 has IMAs dedicated for: * **Avionics** * Ο Displays and Crew Alerting, Flight Data Acquisition and Recording, Flight Management, Thrust Management, Communication Management, Health Management, Data Loading, Configuration Management. * **Environment Control Systems** * Ο Protective, Air Conditioning, Pressurisation, E/E Cooling Systems Control and Indication. * **Electrical Systems** * Ο System Control and Indication, Secondary Electrical Power Distribution, Proximity Sensing, Window Heat. * **Fuel Systems** * Ο System Indication, Fuel Quantity, Nitrogen Generation System. * **Hydraulics** * Ο System Control and Indication. * **Mechanical Systems** * Ο Brake, Landing Gear, and Steering Systems Control and Indication. * **Payloads** * Ο Lavatories, Potable Water, Crew and Passenger Oxygen, Vacuum Waste. * **Propulsion/APU** * Ο Engine and APU Fire Detection and Extinguishing Control and Indication, Thrust Reverser Control and Indication. ### Comparison of Boeing B777 and B787 Avionics systems **Figure 11: Comparison of B777 and B787 avionics** The image shows a comparison of avionics systems between the 777 and 787 aircraft, including Actuator Control Electronics,Primary Flight Control Computer ,Autopilot Flight Director Computer, Power Supply Assembly, and Flap Slat Electronics Unit. The figure includes advantages such as reduced cost, reduced weight, reduced rack space, increased reliability, and reduced wiring and connectors. ### Difference between EMB 170/190 and A380 Integrated Modular Avionics (IMA) On Embraer 170/190 each IMA is a metal cabinet solidly grounded to the aircraft frame. This cabinet is called as Modular Avionics Unit (MAU) and it contains different line replaceable modules (LRM) for different avionics applications. Whereas, on A380 has independent LRMs to host different avionics applications. Some LRMs merge 3 to 4 aircraft systems and handle these systems individually. **Figure 12: Difference between EMB 170/190 and A380 IMA system** The diagram compares the EMB 170/190 concept and the A380 concept relative to LRU's and Systems. ### IMA System on A380 On the A380, the independent applications are hosted in shared IMA modules, called Core Processing Input/Output Modules (CPIOMs), and in order to accommodate and link with the conventional avionics an additional modules are placed in the system, called Input/Output Modules (IOMs). Both CPIOMs and IOMs are LRMs. These LRMs dialogue through the Avionics Data Communication Network (ADCN) by the means of a communication technology developed from a non-aeronautical standard, which has been adapted to aviation constraints. This technology is called Avionics Full Duplex switched ethernet (AFDX). The major components of A380 IMA system are: * Core Processing Input/Output Modules (CPIOMS) * Input/Output Modules (IOMs) * Avionics Data Communication Network (ADCN) **Figure 13: IMA concept on A380** Figure 13 shows a diagram of a LRU, Function vs Application Matrix with components such as Conventional Avionics, Integrated Modular Avionics , Line Replaceable Module",Avionics Data Communication Network ,Core Processing Input/Output Modules,and Input/Output Modules ### Core Processing Input/Output Module (CPIOM) The CPIOM integrates shared memory and computing resource to execute independently its hosted avionics applications. In addition, the CPIOM processes independently specific input/output data for each application. This data is AFDX data. When the applications dialogue through ADCN and non-AFDX data when they dialogue directly with conventional LRUs. There are 7 types of CPIOM, each one identified by a letter (A to G) for following systems: * **Pneumatic applications (X4)** * Engine Bleed Air system, Overheat Detection System, Pneumatic Air Distribution System. * **Air conditioning applications (X4)** * Air Generation System, Avionics Ventilation System, Cabin Pressure Control System, Temperature Control System, Ventilation Control System. * **Cockpit and flight controls applications (X2)** * Flight Control, Weight and Balance Computation, Flight Warning System. * **Data link applications (X2)** * Air Traffic Control system, Avionics Communication. * **Energy applications (X2)** * Circuit Breaker Monitoring System, Electrical Load Management System. * **Fuel applications (X4)** * Fuel CG measurement COM, Fuel management. * **Landing gear applications (X4)** * Braking control system, Steering control system, Landing Gear Extension and Retraction System. **Figure 14: CPIOM** This diagram of CPIOM systems includes elements such as Avionics Applications,AFDX (Avionics Data Communication Network), Non AFDX,LRUs, Computing Resource, Memory Resource, Input/Output Resource. Components of CPIOM A CPIOM is composed of: * Hardware Boards * Field Loadable Software **Figure 15: Hardware boards** The image is of an assembly of hardware power I/O cards, AFDX and system cards, I/O C1 cards, I/O C2 cards. **Figure 16: Software** The software diagram shows a CPIOM module architecture (ATA XX, ATA YY, ATA ZZ, HARDWARE, Analog ARINC, ADCN....). ### Hardware Boards * Power supply board- connected to the 28 VDC. * Inputs/outputs boards - connected to the aircraft systems through analogue, ARINC, Controller Area Network (CAN) and/or discrete signals. * Central Processing Unit (CPU) board - supporting an AFDX END system board, supplies an AFDX interface to the CPIOM to exchange AFDX data with the ADCN. Figure 17 is a diagram of hardware boards including elements such as CPU,CPU Board,AFDX Board, Power I/O Board, and I/O Boards. The diagram depicts components connecting to an ARINC600 connector and a Backplane board. **Figure 18: Field loadable software** The field loadable software diagram includes elements such as ATA xx Software,ATA yy Software,ATA zz Software, OPERATING SYSTEM , configuration Table Software. ### Example for Avionics Application Software: The CPIOM for Cockpit and Flight controls application holds database for ATA 27, 22, and 31 related software. **Figure 19: Application software** The application software diagram shows elements such as ,CPIOM-C1 CPIOM-C2 ,LOADABLE SOFTWARE,COCKPIT & FLIGHT CONTROLS. **Figure 20: Input/Output module** Figure 20 shows elements such as LRUS , INPUT/OUTPUT RESOURCE,Avionics Data Communication Network . * Input/Output Module (IOM) The IOM does not host avionics applications. The IOM converts non-AFDX data, coming from conventional LRUs, into AFDX data used within the Avionics Data Communication Network (ADCN) and vice versa. All IOMs are fully interchangeable. * IOM Components An IOM is composed of: ### Hardware Boards * Power supply board- connected to the 28 V DC. * Inputs/outputs boards - connected to the aircraft systems through analogue. ARINC, Controller Area Network (CAN) and/or discrete signals. * Central Processing Unit (CPU) board - supporting an AFDX END system board - Supplies an AFDX interface to the IOM to exchange AFDX data with the ADCN. **Figure 21: Field loadable module software** The field loadable module software diagram includes elements such as POWER SUPPLY BOARD INPUT/OUTPUT BOARD, CENTRAL PROCESSING UNIT CPU, AND AFDX,analog systems. ### Avionics Data Communication Network (ADCN) Subscribers The aircraft system computers connected directly to the ADCN are the LRMs, which are CPIOMs or IOMs. These computers are called ADCN subscribers. The communication between the ADCN subscribers is done through the AFDX technology. ### ADCN and AFDX Technologies The ADCN is supported by the AFDX technology. The AFDX is a communication technology based on commercial Ethernet protocol adapted to aeronautical constraint to meet the avionics requirements. It gives the following advantages: * Secure and reliable communications * High data rate 10 and 100 Mb/s * Flexibility for future developments of system architecture * Less wiring The ADCN is made of AFDX switches and AFDX cables. The AFDX switches are electronic devices. They manage the data traffic on the network between the connected subscribers. **Figure 22: AFDX switches** The image shows the configuration for three AFDX, and the cable linking them The AFDX cable is a Full Duplex physical link between a subscriber and an AFDX switch. (The term Full duplex means that the subscriber can simultaneously transmit and receive on the same link). This link is a QUAD cable, composed of four wires uniformly twisted, one pair for transmission and one pair for reception. **Figure 23: AFDX cable** The image shows the configuration for the AFDX connectors and associated cables. **Figure 24: ARINC600 connector of a CPIOM** The image is of an ARINC600 connector with the quadrax connectors for AFDX. **Figure 25: ADCN network** The figure represents AFDX and ADCN components and structure. For availability reasons, the ADCN implements a redundant network. Indeed, all ADCN subscribers have a connection to both redundant networks A and B and with auto switching system. ### Typical IMA version of Bleed Air Management (A380) The pneumatic applications such as Engine Bleed Air System, Overheat Detection System and Pneumatic Air Distribution System are controlled and monitored by a single Line Replaceable Module (LRM) in the IMA system. On A380, this application is hosted in 4 identical CPIOMs for redundancy purposes. These CPIOMS are dedicated to monitor and control: * Pneumatic Air Distribution System (PADS) applications * Engine Bleed Air System (EBAS) applications * Overheat Detection System (OHDS) applications For example, by pressing the APU BLEED push button switch located on the AIR panel, the APU bleed air supply is activated. The signal is received by the 4 CPIOMs-A, which command the APU isolation valve to open. At the same time, the Electronic Control Box (ECB) receives data through the Avionics Data Communication Network (ADCN) or with discrete signal to command the opening of the APU bleed valve. Now, the APU bleed air available in the system. **Figure 26: Typical bleed system** The figure is a schematic for the Engine Bleed air system on the A380, including components such as PACKs, Bleeds, and the ADCN. If a leak is detected, the system is protected by a specific leak system loop which sends a signal to the CPIOM-A. Then the Over-Heat Detection System (OHDS) application hosted in the CPIOM-A triggers appropriate valve closure and sends a leak message to the: * Flight Warning System (FWS) * The Control and Display System (CDS) for indication * The Onboard Maintenance System (OMS) for leak localisation **Figure 27: Typical leak detection** Image depicts an aircraft cockpit with an indicator to show an overheat in a duct. In view of the above examples, it is understood that the different applications are hosted by a single platform with modular technology to accommodate different systems simultaneously. ### Maintenance Practices * Software Control The Data Loading and Configuration System (DLCS) is part of the Onboard Maintenance System (OMS). The DLCS application is composed of four functions: * Data Loading function * Repository management function * Configuration reporting function * Software pin programming function Correct software loads and software configurations are critical to the IMA concept. A software mismatch or incorrect loading procedures could conceivably cause a disastrous sequence of events. Especially on the A380, all LRM are interchangeable physically, however the software differences will construct the required concept for its operation in a particular system. Even to change the position of identical LRMs in the same system required software changes. **Figure 28: LRM interchangeability** The image shows the data management and loading structure into and out of the computer system, which dictates that the correct data is loaded. It is imperative that maintenance manuals are strictly followed when loading software, and that software and system functional and confidence checks are performed following software loading. Any Field Loadable Software (FLS) loading should be recorded in the Aircraft Configuration List (ACL), and a copy kept onboard the aircraft with a further copy also kept in the operator's aircraft maintenance records system. After any loading of a Loadable Software Aircraft Part (LSAP) a Certificate of Release to Service must be issued by an appropriately authorised Line/Base Maintenance Staff. It is essential that operators have appropriate procedures in place such that, at any time it is possible to determine the equipment, and software configuration of each aircraft in their fleet. **Figure 29: LRM cabinet** The image shows a detailed photo of the cabinet which accepts the replaceable LRMs. ### Hardware Precautions Extra concern is needed when handling LRM as some of them are PCBs needing ESD protection. Also, during installation take care of connecting pins and sockets as they are delicate and with finer arrangements. BITE and System Checks The BITE information processed by the systems and sent to the CMS applications. The BITE information collected thus gives the CMS to monitor and to detect the systems failures. It is also possible to initiate manual tests from the CMS (interactive mode) in order to interrogate the systems on particular components or system status. Carry out functional tests when called for in the schedule, or when a fault has been reported, should be done in accordance with procedures laid down in the maintenance manual. **Figure 30: Typical reset panel (A380)** The panel has multiple systems with their own circuit breakers. The relevant maintenance manual would contain a detailed description of the correct approach to reset the system. ### Reset Management Some of the IMA system on A380 could be reset as per relevant AMM, using reset pushbuttons. Each reset P/B (power breaker) will reset the software of the corresponding application.