1. SAE E-32 Committee
Meeting No. 66
Seattle - WA, April 4th-6th 2006
EHM System on the E-Jets Family
Gustavo Adolfo Telo de Faria
Propulsion System Eng.
2. Introduction
Presentation Scope:
• E-jets. (Embraer 170/190 Program)
• Focus on data acquisition system for EHM Computer Based Methods.
• System Overview
• Highlights (Comparison to the System Implemented in the Embraer
Previous Programs - advantages)
• Conclusion
4. • Among other very important functions, FADEC monitors engine data to
determine:
• When to request trend data saves at the CMC,
• When limit exceedances are to be tracked and reported on the
CMC and EICAS.
• The FADEC supplies data to other aircraft avionics (MAUs) via ARINC
429. This data will aid in detection, reporting and storage of faults, engine
dispatch level and exceedance information.
• FADEC NVM records active faults and displays it on the MFD for engine
dispatch evaluation, even with the CMC off.
FADEC ROLES ON EHM
5. CMC ROLES ON EHM
• The CMC provides the following EHM functions:
a. Display of detected engine maintenance faults
(troubleshooting)
b. Display of current engine data
(eng. config. data)
c. Storage and transfer of fault indications
d. Storage and transfer of trend data
e. Storage and transfer of exceedance data
6. ECM on the E-Jets
CMC
GE´s
SAGE®
DCU
Ground station
FADEC
EVM
CAS / MFD
INDICATION
EXCEEDANCES
+ MAINT.
FAULTS
Trend Files
trend & exceedance
files download
Automatic trend &
exceedance data
recording
On board
On ground
ACARS
EHM DATA FLOW CHART
8. ENGINE EXCEEDANCE DATA
Engine Limit Exceedence - Detection and Reporting
• FADEC includes logic to monitor engine related parameters and detect limit
exceedances.
•The Amberline and Redline limit values are determined by the FADEC.
• The FADEC monitors a number of inputs and performs a number of tasks if
an exceedance is detected:
• Individual timers for each exceedance
• The peak (or lowest) value seen during the flight will be kept.
• The peak values and exceedance durations will be saved in NVM
• An ARINC 429 bit will be set to indicate an exceedance has occurred
• The following parameters are tested for limit exceedance:
• N1, N2 and ITT
• Oil Level, Temperature and Pressure
• N1, N2 Vibration
9. ENGINE EXCEEDANCE DATA
Storage of Exceedance Data
• Exceedance events are logged in the CMC. (ACMF Report)
• CMC saves 10 seconds of pre event and 15 seconds of post event data
• CMC capable of recording up to 50 exceedance data sets
• CMC Exceedance / Maintenance faults will not be cleared unless commanded to
be reset from the MFD.
• FADEC saves exceedance data (peak and duration) in its NVM (CMC off.
• CMC records the following data for each exceedance event:
- Aircraft Serial Number - Date
- Time - FADEC ID (SDI code)
- Flight Leg - Flight Phase
- Specific data set, as configured in the CMC
10. Trend Data Acquisition
• Takeoff and cruise trending data taken using engine and
aircraft data and detection logic.
• Each data set is a collection of 52 parameters,
• Data stored in the CMC to be downloaded at least once a
week.
• The data is retrieved from the CMC by a DMU or a laptop
computer.
• Trend Reports can be also transmitted through ACARS
TREND DATA
11. Takeoff Data Trigger Timing
• Recorded during the takeoff flight phase at the time when
ITT has peaked.
• Algorithm in the FADEC determines when takeoff data
should be acquired.
• Capturing Criteria:
• Based on ITT and TLA.
• When the throttles are in takeoff position, ITT will be monitored.
• When ITT has dropped below the peak value, a trend point will be
requested.
TREND DATA
12. Cruise Data Trigger Timing
• Recorded when stable engine operation is detected by the
FADEC.
• This condition signal is sent to the CMC, that initiates the snap
shot record.
• Capturing Criteria:
a) altitude greater than 20,000 feet for at least 5 minutes, and
b) altitude has not changed by more than + 100 feet for at least 5 minutes,
and
c) Mach number is between 0.60 - 0.90 for at least 5 minutes, and
d) Wing and nacelle anti-icing bleed is off
TREND DATA
13. Storage of Trend Data
• CMC records the trend points
• The CMC will save up to 200 trend points total.
• Allows a weekly data download interval assuming a maximum of 10
flights a day, 7 day operation with margins.
• Trend points are not cleared unless overwritten by newer trend points.
• CMC will record the following data for each trend point event:
- Aircraft Serial Number
- Date
- Time
- FADEC ID (SDI code)
- Flight Leg
- Flight Phase
- Specific data set, as configured in the CMC
TREND DATA
14. EHM Algorithm at the FADEC:
• At previous Embraer programs, trend data recording logic
is within CMC.
• On the E-Jets, data is stored at the CMC but the recording
logic is completely implemented in the FADEC SW
• Provides much more flexibility for changes / improvements
• Autonomy for the engine supplier / Embraer to improve the system
without demanding new releases of other LRUs.
E-Jets EHM Highlights
15. Integrated ASCB Data Bus:
• On the E-Jets, data from all aircraft systems are routed to a
common data bus (ASCB), which can be accessed by all
systems linked to the bus, including the FADEC.
• E-Jets “highly integrated aircraft”
• The FADEC can “see” data from several engine related aircraft
systems
• Trend reports can take advantage of that and record more data
• E.g.: E-Jets TO trend reports 52 parameters
ERJ-145 Family TO trend reports 34 parameters
• Trend plots can be more accurate, since they are more properly
normalized.
E-Jets EHM Highlights
16. E-Jets EHM Highlights
Integrated ASCB Data Bus:
• Do the benefits in terms of EHM justify the implementation of a highly
integrated architecture?
17. E-Jets EHM Highlights
CMC Files Storage Capacity:
• ERJ-145 records up to 75 flight legs.
• On the E-Jets, the CMC can record up to 200 flight legs
• CMC is only responsible for the recording, as per FADEC command
• Memory saved by the algorithm used to improve storage capacity
18. E-Jets EHM Highlights
Engine Exceedance Historic Data:
• On other programs, engine exceeedance were snapshots
• Deeper research demands DFDR downloads to be completed
• More time consuming tasks
• On the E-Jets, CMC saves 10 seconds of pre event data
and 15 seconds of post event data
• Most of the times, exceedance files samples are enough for a
good evaluation
• No need of additional LRUs downloads.
• Minimizes workloads and errors from line maintenace
personnel
19. E-Jets EHM Highlights
ACARS capabilities standard and since the beginning:
• In the ERJ-145 program, trend data transmission via
ACARS was developed after initial release and offered as an
optional feature. .
• On the E-Jets, ACARS is standard.
• No need for retrofits the system is already in.
• Data transmitted on line helps the airlines operations and
immediate perception of step changes on EHM plots.
• Minimizes workload and errors from line maintenance personnel
20. Conclusion
• EHM functions is continuously evolving.....
• ERJ 145 system vs E-Jets system
• EHM functions and features implemented according to:
• Engine suppliers recommendations and,
• Aircraft capabilities
• Further improvements under evaluation:
• E.g.: Engine Starting Trend Monitoring
Detection of Ignition / Fuel Nozzles / OBVs
SCVs Issues / Etc.
