The primary functions of the engine condition-fault reporting (EC-FR) system are to supply engine condition and performance data that are used to give engine EICAS messages, and to help make engine maintenance more efficient.

The EC-FR system gives, at the correct time, the data that is necessary to do engine maintenance. With the EC-FR system, engine life can be extended, and maintenance time, efforts, and costs are reduced.

To supply these functions, the EC-FR system does engine life-cycle-cost control that is related to operational data. The system uses an electronic module that continuously monitors and records key engine parameters, does the analysis of this data, and finds the trend in the engine operation conditions. The module is a part of the electronic control unit (ECU) of the full-authority digital engine-control (FADEC) system.

The EC-FR system receives/sends data from/to the other aircraft systems, through the FADEC system interfaces. The EC-FR engine condition and fault data that is necessary to identify engine dispatch status or maintenance tasks, is given to the engine indication and crew alerting system (EICAS). The EC-FR data transmitted to the EICAS can be shown on the multi-function display (MFD), with the use of the maintenance diagnostic computer (MDC). The EC-FR data can also be downloaded to a personal computer (PC).

The engine condition-fault reporting (EC-FR) module is an electronic unit that is a part of the ECU. The EC-FR module functions with its related software, supplies the primary functions of the EC-FR system.

The EC-FR module monitors engine health and performance data at all power settings, and examines built-in-test (BIT) data. It can identify the most logical defective component when a fail condition occurs. The EC-FR module gives dispatch status when necessary. Also, it supplies the maintenance crew with data that helps for efficient fault-isolation and better repair operations on the aircraft propulsion system.

The data collected and used by the EC-FR system is the same data used by the FADEC for the engine control. The system also gives access to all data in the FADEC. With this system configuration, there is no necessity to add independent sensors or processors which operate for the EC-FR system only. Thus, with the module installed as a part of the ECU, the EC-FR system is made more efficient than a separate hardware system.

The System Operation includes:

EC-FR System Functions

To supply its outputs, the EC-FR system collects and records data from the different engine components and sensors and uses the different functions of the EC-FR module to examine the data, and to supply the necessary operational and maintenance data. The EC-FR module supplies all the EC-FR system functions that follow:

• FADEC EC-FR Data-integrity
• Fault Detection, Diagnostics and Reporting
• Maintenance Conditions (TLD)
• Time Limited Dispatch (TLD)
• Engine-Condition Data Collection
• Engine Exceedance Monitor
• Event Recorder
• Life-Usage Recording
• FADEC EC-FR Data-Downloading

FADEC EC-FR Data-integrity

The FADEC EC-FR data integrity function does continuous checks to make sure valid data is obtained, kept, and transmitted. At first installation, ECU software and hardware identifiers, and engine property data, are supplied to and kept by the ECUs.

The maintenance personnel must initialize the EC-FR data files at first installation of the engine. Also, when an ECU is replaced, the EC-FR data files must be initialized. If an ECU is installed and not initialized, data collection is stopped. An ECU NOT INITIALIZED maintenance code is recorded, until the start is completed. The ECU will operate correctly except for the data collection function.

The EC-FR module monitors the ECU, engine, and aircraft data, while data is kept and transmitted. The system has a non-volatile memory (NVM) capacity for 100 flights. A DOWNLOAD FADEC message is given (on the personal computer display) at 75 to 80 percent NVM capacity. The message tells personnel that a download is necessary. If a download is not completed in the correct time, the oldest performance data in memory is overwritten when there are more than 100 flights. All life use and fault data is kept in the NVM until downloaded

Fault Detection, Diagnostics and Reporting

With the fault detection, diagnostics and reporting function, the EC-FR module can identify the most logical fault component when a fail condition is sensed. First-time system faults are isolated in a 95 percent ratio. This EC-FR function gives fast and accurate problem identification, and helps to have safe and cost-effective maintenance programs.

The BIT software of the ECU monitors the systems and components. The BIT of systems and circuits is done at the same time by the two ECUs. The BIT monitors during ECU power-up, power-down, and operation. This is necessary as the tests on some systems and components, occur only during flight conditions, operation modes, or when the applicable systems/components are in use.

Maintenance Conditions

BIT results are read by the EC-FR module, and changed to maintenance conditions (MCs) that isolate faults to a specific component. MCs will also be defined for other specific engine conditions or events that make maintenance operations necessary.

MCs are processed when they occur and numerical identifiers are given to each MC. MCs are kept up to date together with the ECU operating time, date, Greenwich mean time (GMT), and flight number occurrences. Primary engine parameters and flight condition data are also kept up to date.

With the use of the electronic engine interface (EEI) software, maintenance personnel can have access to the MCs through the EICAS maintenance page that shows on the PC. After completion of maintenance task to correct one or all MCs, an operator-initiated maintenance reset must be done. This can be done with the PC and the EEI software.

Time Limited Dispatch

One of the most important functions of the EC-FR module is to supply time limited dispatch (TLD) status. This function supplies the flight crew with a go/no go indication of engine dispatch status. TLD function lets the flight crew have unlimited operation of the engine with a number of known control-system faults, for specified periods.

The TLD status of the engine is based on fail conditions (which cause loss of input/output redundancy or functions) that have effects on the FADEC ability to control engine thrust. BIT results are read by the EC-FR module to determine what functional faults (FF) exist. This causes some degree of loss of thrust control.

Logic in the EC-FR module then uses the FF to determine TLD status. 

Engine-Condition Data Collection

The EC-FR module monitors engine-operation parameters during all phases of operation. A set of these engine parameters will be locked on and kept during takeoff, climb, and cruise flight. The EC-FR keeps the engine operation conditions and performance data as snapshots in the NVM for 100 flights.

The engine condition or performance data collected and kept by the EC-FR module can be seen through the use of the FADEC port. The data can also be downloaded to a PC for transmission to a central maintenance facility.

Engine Exceedance Monitor

The EC-FR system includes an engine exceedance monitor. The engine exceedance monitor continuously monitors a set of engine parameters to verify if their values are more than the system limits.

All exceedances are identified, in relation to the severity of the exceedance, as:

• Type 2 exceedance
• Type 1 exceedance
• Type 0 exceedance

All exceedances are reported as a fault/advisory and shown to the flight crew.

Type 2 exceedance is the most severe of all exceedance types. A type 2 exceedance event record is written to the NVM, because a type 2 exceedance is considered an event trigger. The type 2 exceedance is logged to the NVM as an MC, and makes it necessary to do a maintenance operation before dispatch.

Type 1 exceedances are minor exceedances. These are warnings to maintenance personnel. Type 1 exceedances are logged as an MC, and the only maintenance operation that is necessary is to make logbook entries.

Type 0 exceedances are operations above the aircraft certified limit, but below the engine certified limit. For type 0 exceedance, no maintenance operation is necessary.

Event Recorder

Faults, exceedances, unusual events, and pilot commands, are event triggers that start the record operation. The event recorder records a three-minute window of data around the event trigger time. When an event is sensed, the EC-FR module event-recorder locks on a history of a set of 20 engine parameters. These engine parameters are recorded in the NVM.

The recorder is started automatically when a type 2 exceedance or when one of several specific events occurs. Also, the pilot can always start the recorder manually. There is enough capacity to record one pilot started event and three automatically sensed events between EC-FR downloads. Pilot-started events overwrite previous pilot-started events.

Events will be recorded in a high resolution (parameters recorded every 100 milliseconds) and a low resolution (parameters recorded every two seconds) as follows:

• The low-resolution event history starts two minutes before, and stops one minute after the event trigger occurs
• The high-resolution event history starts 20 seconds before, and stops 10 seconds after the event trigger occurs.

Life Usage Recording

The life-usage recording function keeps the history of some aircraft and engine operation parameters which accurately give the rate of engine component life-usage. This makes possible more accurate calculations of the remaining-life for some components.

The life-usage recording function adds and keeps in storage the number and duration of the parameters/conditions that follow:

• Total engine operation-time
• Total engine flight-time
• Number of takeoffs, landings, and touch and goes
• Number of starts
• Total ignition exciter and igniter use
• ECU operation time
• Total N1 and N2 speed, temperature and pressure cycles
• Total static-pressure cycles
• Rotating component time at temperature and speed.

FADEC EC-FR Data-Downloading

Data download from the EC-FR system is done with the use of a personal computer together with the EEI software, through the aircraft FADEC data-port.

The EEI software is also used to initialize the ECU when an ECU is replaced or an engine is installed on the aircraft.

Before the software will let initialization data to be entered, it will do a check of the ECUs for EC-FR data which has not been downloaded. If data is in the memory, the software will tell the user that the data must be downloaded and the memory must be cleared. The software will then ask the user to enter initialization data for the engine and for each ECU.

EC-FR System Outputs

Output to the EICAS

The EC-FR engine condition and fault data that is necessary to identify engine dispatch status or maintenance operation, is given to the EICAS. The data is transmitted through an aeronautical radio incorporated (ARINC) 429 data bus.

The faults and exceedance reported by the EF-CR system are identified as warnings (red), cautions (amber), advisories (cyan), or status (white). A list of the engine related CAS messages is given in the description of the FADEC system.

Output to the MDC

The EC-FR data transmitted to the EICAS can be shown on the copilot MFD, with the use of the MDC functions. The fault data supplied to the MDC includes all the data necessary to do task-oriented maintenance. The EC-FR system uses ARINC 429 for the communication with the MDC. The faults reported by the MDC through the EC-FR function, show on a list given by ATA chapter sequence.

Output to a PC

The EC-FR data can be downloaded to a personal computer, through an RS 422 link. Data downloaded to the computer contains more details than the data shown on the MDC.

For the download operation, the personal computer is connected to the FADEC port installed on the maintenance panel, in the LH equipment rack.