ONBOARD MAINTENANCE SYSTEM
Purposes
Provide maintenance personnel with an aid to fault diagnosis further to a complaint of the crew, thus saving time and money in the maintenance of the aircraft Enabling technology; hosting a wide range of airlinespecific software applications, including cabin information applications, graphical weather depiction, document viewing etc.
Purposes
Provide maintenance personnel with an aid to fault diagnosis further to a complaint of the crew, thus saving time and money in the maintenance of the aircraft Enabling technology; hosting a wide range of airlinespecific software applications, including cabin information applications, graphical weather depiction, document viewing etc.
Multi Function Computer System (MCFC) – ATR72
Multi Function Computer System (MFC) As fitted to the ATR72 Two independent computers (MFC1 & MFC2)
Two independent modules (A & B) Receives signal from all the various systems and system controls Self-test capability to ensure it is operation correctly
MFC Maintenance Panel
Bite Load Indicator System Selector Switch Bite Advisory Display PTA/ERS Pushbutton Test Pushbutton Data Bus Connector
MFC Control Panel Located on the overhead panel Allows the switching on and fault monitoring of the MFC system
On : (Pushbutton pressed in) Module operates Off : (Pushbutton released) Module stops operating FAULT : Amber light comes on and the CCAS is activated when a malfunction or electrical supply fault is detected.
3 Classes of Faults
Class 1
Class 2
May have operational consequences on the current flight Do not have any operational consequences on the current flight or following flights
Class 3
No consequences on aircraft safety or availability Unlike Class 1 and Class 2 faults, these faults are not indicated to the crew
Built-In Test Equipment (BITE)
A part of the computer dedicated for
Permanent Monitoring
Internal monitoring Input / Output monitoring
Link Monitoring
Between LRUs within the system
Built-In Test Equipment (BITE)
To meet requirements such as :
To meet constraints such as :
high reliability Lower repair cycle times Limited technician accessibility Cost of testing during manufacture
To minimize the time on the ground needed for repair To increase the level of safety of the system which contains BIST
Built-In Test Equipment (BITE)
Two types of test :
Operational test
Input signals Protection Circuitry Control Circuitry Output Signals Operations BITE Circuitry
Maintenance test
Carried out only when required and when the aircraft is on the ground
Built-In Test Equipment (BITE)
Built-In Test Equipment (BITE)
Built-In Test Equipment (BITE)
Type1 ARINC 429 input and output bus, the input being specific to the CFDS Capable of memorizing data concerning faults detected on a maximum of 64 flights 34 basic and nine optional systems, total 75 units
Built-In Test Equipment (BITE)
Type2 A discrete and an ARINC429 data bus input from the CMC Ten basic systems, total of 19 units
Type3
Characterized by discrete inputs and outputs Four basic and one optional system, total of 8 units
Built-In Test Equipment (BITE)
Central Maintenance Computer(CMC) All faults are recorded in the non-volatile memory Detects faults in two ways :
Internally By monitoring its own operation Externally By another aircraft system which received and monitored information from the „faulty‟ system
Multi-purpose Disk Drive Unit (MDDU)
Two functions : Uploading Data Downloading Data
Built-In Test Equipment (BITE)
Multi-function Control and Display Unit (MCDU)
Provides an interface for ACARS Used almost all the times since it is the primary means of operating the aircraft
Built-In Test Equipment (BITE)
Aircraft Communications Addressing and Reporting Systems (ACARS)
A digital datalink system for transmission of short, relatively simple messages between aircraft and ground stations via radio or satellite
MCDU menu differs in report for ON GROUND and IN FLIGHT
Built-In Test Equipment (BITE)
Panel for an aircraft model POSKY Boeing 737-800 with attached MCDU
Air Transport Association – ATA
Provide a common referencing standard for all commercial aircraft documentation The standard numbering system is controlled and published by the Air Transport Association (ATA)
Air Transport Association – ATA AIRCRAFT GENERAL
ATA Number
ATA 01
ATA 05
Chapter Name
INTRODUCTION TIME LIMITS/MAINTENANCE CHECKS
ATA 06
DIMENSIONS AND AREAS
ATA 07
LIFTING AND SHORING
ATA 08
LEVELING AND WEIGHING
ATA 09
TOWING AND TAXIING
ATA 10
ATA 11
ATA 12
PARKING, MOORING, STORAGE AND RETURN TO SERVICE PLACARDS AND MARKINGS SERVICING - ROUTINE MAINTENANCE
Air Transport Association – ATA AIRFRAME SYSTEMS
ATA Number
ATA Chapter name
ATA 20
STANDARD PRACTICES – AIRFRAME
ATA 21
AIR CONDITIONING AND PRESSURIZATION
ATA 22
AUTOFLIGHT
ATA 23
COMMUNICATIONS
ATA 24
ELECTRICAL POWER
ATA 25
EQUIPMENT/FURNISHINGS
ATA 26
FIRE PROTECTION
ATA 27
FLIGHT CONTROLS
ATA 28 ATA 29 ATA 30
ATA 31
FUEL HYDRAULIC POWER ICE AND RAIN PROTECTION
INDICATING / RECORDING SYSTEM
Air Transport Association – ATA ATA Number AIRFRAME SYSTEMS
ATA Chapter name
ATA 32
ATA 33
ATA 34
ATA 35
ATA 36
ATA 37
ATA 38
ATA 45
LANDING GEAR
ATA 46
LIGHTS NAVIGATION OXYGEN PNEUMATIC VACUUM WATER/WASTE
DIAGNOSTIC AND MAINTENANCE SYSTEM INFORMATION SYSTEMS
ATA 47
NITROGEN GENERATION SYSTEM
ATA 48
IN FLIGHT FUEL DISPENSING
ATA 49
AIRBORNE AUXILIARY POWER
ATA
CARGO AND ACCESSORY COMPARTMENTS
Air Transport Association – ATA
STRUCTURE
ATA Number
STANDARD PRACTICES AND STRUCTURES - GENERAL
ATA 51
ATA 52 ATA 53 ATA 54
ATA 55
ATA 56
ATA Chapter name
ATA 57
DOORS FUSELAGE NACELLES/PYLONS STABILIZERS WINDOWS WINGS
Air Transport Association – ATA ATA Number POWER -PLANT
ATA 61 ATA 71
ATA 72
PROPELLERS POWER PLANT ENGINE ENGINE - FUEL AND CONTROL
ATA 73
ATA Chapter name
ATA 74 ATA 75
IGNITION BLEED AIR
ATA 76
ENGINE CONTROLS
ATA 77
ENGINE INDICATING
ATA 78 ATA 79 ATA 80
EXHAUST OIL STARTING
Data Loading
Navigation information required by the aircraft systems is loaded using “Data Loaders” Capable of downloading thousands of byte of information into the required system in a matter of seconds
Navigation Data Base (NDB)
Describes the environment in which the aircraft operates Defined via the ARINC 424 standard Normally updated every 28 days, to ensure that its content are current
Navigation Data Base (NDB)
Type of information
Approaches
Standard Terminal Arrival Route (STAR) Instrument approach
Waypoints/Intersection Airports Runways Holding Patterns
Maneuver designed to delay an aircraft already in flight while keeping it within a specific airspace
Airways
Highway in the sky
Structure Monitoring
Structural health monitoring is an important safety factor in aviation that might benefit from advanced smart systems for damage sensing and signal processing.
Structure Monitoring
Reasons :
Prevent damage and possible hazard to the aircraft following a catastrophic failure Detection of failures before any real damage has occurred Safety issues To adapt operational usage to limit or even stop damage growth
Low Cycle Fatigue
Low cycle fatigue is a term used to describe the thermal and/or mechanical loading conditions which cause premature failure of materials at less than 20,000 cycles It is important to not have failures of this type for economical and safety reasons
Low Cycle Fatigue
Failure can occur in any area there is metal alloys but usually in the turbine or compressor sections The choice of metal alloys and the design of engine components are the protection methods
Low Cycle Fatigue
Low Cycle Fatigue Counter (LCFC) receives inputs from the engine for such parameters as engine speed (NL and NH) of comppresors and turbines
Processes the information to calculate engine damage cycles Damage cycles are not related to actual damage, but more a measure of the component life being consumed by there critical terms.
Health & Usage Monitoring (HUM)
Developed for fixed-wing aircraft,
but focuses on rotorcraft, which benefit from a system's ability to record engine and gearbox performance and provide rotor track and balance
May also monitor auxiliary power unit usage and exceedances, and include built-in test and flight data recording (FDR) functions
Health & Usage Monitoring (HUM)
Expected to acquire, analyze, communicate and store data gathered from sensors and accelerometers that monitor the essential components for safe flight
data allows operators to target pilot training and establish a flight operations and quality assurance (FOQA) program, to determine trends in aircraft operations and component usage
Health & Usage Monitoring (HUM)
Typical parameters monitored Engine Speed Engine Temperature Engine Pressure Engine Torque Accelerations Vibration Levels Aircraft Stress Built-In Test Exceedance / Event Monitoring Rotor Track and Balance (for rotorcrafts)
Central Maintenance System (CMS) – A330
Central Maintenance System (CMS)
To facilitate maintenance tasks by directly indication the fault messages in the cockpit and allowing some specific tests
Central Maintenance System (CMS)
To give maintenance technicians a central maintenance aid to intervene at system or subsystem level from multipurpose CDUs (Control Display Units) located in their cockpit Two levels of maintenance : Out-station (line-stop) – LRU change At main base (hangar) – Trouble-shooting
Components
BITEs of all electronic systems Two fully redundant CMCs (Central Maintenance Computers) Three MCDUs (Multipurpose Control Display Units)
Also used for : FMGS (Flight Management and Guidance System) ACMS (Aircraft Conditioning Monitoring System) dialogue with the CMC for information display or ATSU, which dialogue initiation tests
One printer
A4 format
Normally only CMC1 is in used.
Cmc2 is use when CMC1 fail.
Modes of Operation
Operates in two main modes :
In flight, NORMAL or REPORTING mode
In NORMAL mode, the CMS records and permanently displays the failure messages transmitted by each system BITE
On ground, INTERACTIVE or MENU mode
In INTERACTICE mode, the CMS allows the connection of any BITE system with the MCDU, in order to initiate a TEST, or to display the maintenance data stored and formatted by the t he systems‟ BITE
3 Classes of Failures
Class 1
Class 2
Failures indicated to the flight crew by means of a flight deck effect Failures which can be left uncorrected until the next scheduled maintenance check Maximum delay of 600 Flight Hours
Class 3
Failures not indicated to the flight crew, with no fixed time quoted for correction
3 Classes of Failures
Class 3 report & print out
Minimum Equipment List (MEL) Also known as Master Minimum Equipment List (MMEL) A categorised list of systems, instruments and equipment on an aircraft which are not required to be operative for flight Any equipment or system which is not included in the MEL must be operative for the aircraft to be allowed to fly
ARINC data buses
ARINC 429
Predominantly use in Airbus aircraft Based upon the integration of data based upon this level data fusion One way communication data bus
One pair of data bus use for transmit data and another pair of data bus use for receive data
ARINC 629
Use in Boeing aircraft Bi-directional data bus for sending and receiving data between multiple avionics LRUs
ARINC 429
Key display elements
Display of aircraft system synoptic and status displays available to the flight crew on the ECAM (Electronic Centralised Aircraft Monitor) displays Use of the three CDUs as a man-machine interface for system test and diagnostic purposes
ECAM displays relating to the following provided by the Display Management Computers (DMCs) Engines Electrical system APU Hydraulic system Landing gear
Central Maintenance Computing System (CMCS) – Boeing 777
Central Maintenance Computing System (CMCS)
Supports both line and extended maintenance functions through menu selections on the MAT and PMAT Used for :
Monitoring the aeroplane‟s systems for faults Processing fault information Supplying maintenance information Monitoring Flight Deck Effects (FDE)
Receives maintenance messages from ACMS (Aeroplane Condition Monitoring System (ACMS), if a fault is detected
Maintenance Access Terminal (MAT)
Display Screen and Controls
Selecting and viewing fault data
Keyboard Stored when not in use Allows certain entries and controls displayed data
Cursor Control Device
Receives power supply of 115V AC via the “MAINT ACCESS TERMINAL” circuit breaker Contains :
Track Ball Selection Keys Brightness Control
Portable Maintenance Access Terminal (PMAT)
Similar functions to MAT Five PMAT receptacles, located throughout the aircraft :
MAT Position Electronics Bay Nose Gear Right Main Gear Bay Stabilizer Bay
Flight Deck Effect (FDE)
The airplane systems monitor conditions related to loss of a system or function. If a condition exists that requires repair or deferral, the airplane system sends FDE data to the AIMS primary display system (PDS). The PDS shows the FDE. Inform the flight and ground crew of the conditions relating to the safe operation of the aircraft FDE data is used along with the aircraft‟s maintenance to isolate the fault
Airplane Condition Monitoring System (ACMS)
Provides a record of selected airplane systems performance and flight conditions for maintenance and Flight Data Monitoring purposes The system consists of :
a Digital Flight Data Acquisition Unit a Digital Flight Data Recorder (DFDR) a Quick Access Recorder an accelerometer a Data Management and Entry Panel
Airplane Condition Monitoring System (ACMS) Accessed through fromats on the MAT, PMAT or the side displays on the flight deck Used to produce reports of :
Analyse airplane performance Analyse trends Report significant events Troubleshot faults
Receives data from the Airplane Conditioning Monitoring Function (ACMF)
Airplane Conditioning Monitoring Function (ACMF)
Combination of standard and custom software method of determining aircraft health through reporting on aircraft systems such as powerplants and structures Sends data to :
Quick Access Recorder (QAR) Maintenance Access Terminal (MAT) Portable Maintenance Access Terminal (PMAT) MAT or PMAT disk drives Flight deck Side Displays (SD) Data Communication Management Function (DCMF)
Quick Access Recorder (QAR) Records data sent from the ACMF onto a 3.5ich, 128MB optical disk, holding 41 hours of data An airborne flight data recorder designed to provide quick and easy access to raw flight data QAR is not required on commercial flights and is not designed to survive an accident
Quick Access Recorder (QAR)
Contains two memories :
Flash Memory (non-volatile)
Holds configuration data, system data and identification files Send this data to the formatter
Formatter Memory Arranges the received data, sends it to the cartridge drive circuits
Cartridge Drive Circuits
Sends data to the 16bit LCD displays :
Stored Data QAR Menus Test Results Messages
Airplane Information Management System (AIMS)
Collects and calculates large quantities of data and manages this data for several integrated aircraft systems Used to assemble the necessary data for the CMCS function Two AIMS boxes handle the six primary flight and navigation display
Four Input/Output Modules (IOM) Four Core Processor Modules (CPM)
Airplane Information Management System (AIMS)
IOM
Transfer data between the software functions in the AIMS CPMs and external sources
CPM – 4 types
CPM/COMM – Communications CPM/ACMF – Aircraft Condition Monitoring Function CPM/B – Basic CPM/GG – Graphics Generator
Flight Compartment Printing System
Supplies high-speed hard copies of text for the following systems : Primary Display System (PDS) Airplane Condition Monitoring System (ACMS) Central Maintenance Computing System (CMCS)
Receives data from the print driver partition of the Data Communication Management Function (DCMF)
