Six Sigma Project CFM56-7B EEC Software Improvement at ATA

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Six Sigma -- Define/Measure/Analyze/Improve/Control Phases GE Aircraft Engines
GE Proprietary Information GE Aircraft Engines
g GE Aircraft Engines
Six Sigma Project
CFM56-7B EEC Software Improvement
at ATA
BPTS # 2002-05-011544
Amandio Morais
ATA Field Service Program Manager
December 2002
2
Six Sigma -- Define/Measure/Analyze/Improve/Control Phases GE Aircraft Engines
GE Proprietary Information GE Aircraft Engines
g GE Aircraft Engines
Project Summary - Page 1
Area/Location: Indianapolis, IN Cluster ID:
Title: Incorporate EEC Improvement at ATA BPTS ID: 2002-05-011544
Who is the
customer?
American Trans Air
Why is this
important?
1) Incorporates many new improvements to the EEC logic
2) Can prevent engine failures/delays/caxs
What do I want to
improve?
1) Load the newest EEC software version ASAP
2) Processing time at ATA
How will I measure
the problem?
1) Monitor engine-related write-ups for engine issues due to old software
2) Monitor ATA incorporation of latest software
Can I trust the
process output (Y)
data?
Yes; receive daily engine reports from Powerplant Engineering
Timing: Start: 9/6/01 Complete: 12/9/02 Implement: 2/1/02
Leader Org.: GCFS
Sponsors: Sponsors: Rod Jarvis Process Owner: American Trans Air
Resources: Project Leader: Amandio Morais MBB/Mentor: Scott Kopczynski
Required for Project Approval Required for Project Closure Optional
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Six Sigma -- Define/Measure/Analyze/Improve/Control Phases GE Aircraft Engines
GE Proprietary Information GE Aircraft Engines
g GE Aircraft Engines Project Summary - page 2
Project Summary - Page 2
How good am I
today?
Z = 1.11; measuring P20 software incorporation
How good do I need
to be?
Z = 6
Variation Source Summary
Vital X Impact on Average/Variation of your Y Improvement Plan
Software release date 100%
Install P22 software into ATA’s EEC’s
once software is released
Control Plan Summary
Vital X Control Plan to insure Improvement is Sustained
Monitor EO release and fleet
incorporation
Monitor engine-related write-ups for issues due to old software logic
Have I reached my
Goal?
Will monitor engine issues once software is incorporated into fleet
Required for Project Approval Required for Project Closure Optional
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Six Sigma -- Define/Measure/Analyze/Improve/Control Phases GE Aircraft Engines
GE Proprietary Information GE Aircraft Engines
g GE Aircraft Engines Project Summary - page 3
Action Plan - Complete if project has open actions
Open Action Items Person Responsible Est / Actual Completion Date
Functional Implementation Status (Excel spreadsheet - double click to open)
Group1 Group2 Group3 Group4 Group5
Engagement Status Committed Plan to Commit Plan to Commit Committed Committed
Committed
Plan to Commit
Does Not Support
Leveragable Project
Where can this project be immediately leveraged? How?
Comments / Lessons Learned
Cost/Benefit Profile (Excel spreadsheet - double click to open)
QX QX QX QX Total
Expenditures $0.00
Savings
Indirect $0.00
Avoidance $0.00
Total $0.00
Required for Project Approval Required for Project Closure Optional
5
Six Sigma -- Define/Measure/Analyze/Improve/Control Phases GE Aircraft Engines
GE Proprietary Information GE Aircraft Engines
g GE Aircraft Engines Project Scope / Objectives
Improve Controls System
Reliability and Event Protection
Capability by Implementing
EEC software upgrades.
Project #2001-09-022199
6
Six Sigma -- Define/Measure/Analyze/Improve/Control Phases GE Aircraft Engines
GE Proprietary Information GE Aircraft Engines
g GE Aircraft Engines CFM56-7B EEC Software P20 Improvement
Defect: Main engine bearing damage following oil loss
Measure: Oil loss event without Low Oil Pressure Warning
- 2 events, ~$2.2M per event
Analyze: Oil loss event led to venting of the oil supply pressure to
ambient. This drove PEO, which measures the difference between the
oil supply pressure and sump pressure, to a large negative value. PEO
was declared invalid leading to suppression of low oil pressure warning.
Improve: Change minimum valid value for PEO to account for this
failure mode in EEC software P/N 1853M78P20.
Control: implement EEC software P/N 1853M78P20 via S/B 73-064.
• Other airline experience due to not incorporating P20 software upgrade
• ATA has 8 engines with old P18 software
7
Six Sigma -- Define/Measure/Analyze/Improve/Control Phases GE Aircraft Engines
GE Proprietary Information GE Aircraft Engines
g GE Aircraft Engines
Defect: LPT damage following engine rollback from idle
Measure: Current rollback/over-temperature logic did not protect the
engine following the rollback event.
- 1 event, ~$3M
Analyze: Current logic requires both N2 <50% and EGT>725 deg C
before automatically turning off fuel (ground only). This can lead to a
long exposure time with N1 = 0 and EGT close to the 725 deg C limit.
Improve: Cutoff fuel flow if N2 falls below 45% independent of EGT in
EEC software P/N 1853M78P20.
Control: implement EEC software P/N 1853M78P20 via S/B 73-064.
CFM56-7B EEC Software P20 Improvement
• Other airline experience due to not incorporating P20 software upgrade
8
Six Sigma -- Define/Measure/Analyze/Improve/Control Phases GE Aircraft Engines
GE Proprietary Information GE Aircraft Engines
g GE Aircraft Engines
Defect: IFSD due to false oil temperature indication
Measure: Oil temperature was falsely indicating high leading to IFSD.
- 2 IFSD’s
Analyze: Current TEO signal selection logic is programmed to select the
higher of the 2 channels if they disagree. The failure mode of the sensor
is for a channel to drift high leading to the selection of the false high
channel.
Improve: Use prior history of the TEO signals to determine the health of
each channel. Pick the healthier of the two channels if they disagree in
EEC software P/N 1853M78P20.
Control: implement EEC software P/N 1853M78P20 via S/B 73-064.
CFM56-7B EEC Software P20 Improvement
• Other airline experience due to not incorporating P20 software upgrade
9
Six Sigma -- Define/Measure/Analyze/Improve/Control Phases GE Aircraft Engines
GE Proprietary Information GE Aircraft Engines
g GE Aircraft Engines
Defect: ATO and D&C’s due to no engine response to throttle increase
Measure: Faulty TRA signal falsely indicating high leading to ATO’s and D&C’s.
- 1 ATO, numerous D&C’s
Analyze: Current throttle signal selection logic is programmed to select the lower of
the 2 channels if they disagree. The failure mode of the throttle resolver is to drift
low leading to the selection of the faulty low channel. Therefore, when the pilot
advances the throttle, the faulty channel indicates idle and the correct channel
indicates high power. The EEC chooses the lower position and the engine remains at
idle.
Improve: Use prior history of the TRA signals to determine the health of each
channel. Pick the healthier of the two channels if they disagree in EEC software P/N
1853M78P20.
Control: implement EEC software P/N 1853M78P20 via S/B 73-064.
• Other airline experience due to not incorporating P20 software upgrade
CFM56-7B EEC Software P20 Improvement
10
Six Sigma -- Define/Measure/Analyze/Improve/Control Phases GE Aircraft Engines
GE Proprietary Information GE Aircraft Engines
g GE Aircraft Engines
Defect: D&C’s due to No Go fault for the HPTACC system
Measure: 18 D&C’s per year for spurious HPTACC demand/position
disagree faults.
Analyze: Currently the HPTACC valve position is scheduled as a function
of N2, altitude, time, TC and T3. Oscillating T3 or TC input due to a faulty
signal causes an oscillating HPTACC valve position demand. Because the
valve cannot keep up with this oscillating demand, an HPTACC
demand/position disagree fault is set which is a No Go fault.
Improve: Do not use the TC and T3 input to schedule the HPTACC valve.
Schedule the valve using only N2, altitude and time in EEC software P/N
1853M78P20.
Control: implement EEC software P/N 1853M78P20 via S/B 73-064.
• Other airline experience due to not incorporating P20 software upgrade
CFM56-7B EEC Software P20 Improvement
11
Six Sigma -- Define/Measure/Analyze/Improve/Control Phases GE Aircraft Engines
GE Proprietary Information GE Aircraft Engines
g GE Aircraft Engines CFM56-7B EEC Software P21 Improvement
• Ps3 Signal Selection
-Modification to range checking to improve detection of disconnected Ps3 line
• VSV/VBV Selection logic
-Improvement to current selection logic robustness by using a fault history similar
to FMV selection
• Start Lever Selection Logic
-Current logic prevents engine starts with single point failure in start lever
+ DEU 1 and DEU 2 discrete signals not fully independent (share same start
lever relay)
-New logic to use the two analog EEC reset discrete and two igniter voltages in a 2
out of 4 or 3 out of 4 voting scheme
• VBV Disagree Fault Tolerance
-Disagree fault threshold to be changed from a constant 4 degrees to a variable as
a function of VBV door position
+Maintain current 4 degrees threshold at high power
+Increase threshold at low power to prevent inadvertent faults from being set
12
Six Sigma -- Define/Measure/Analyze/Improve/Control Phases GE Aircraft Engines
GE Proprietary Information GE Aircraft Engines
g GE Aircraft Engines CFM56-7B EEC Software P21 Improvement
• N1 Trim Washout Function
-Modify washout function so that trim is ramped out between 103.5% and 103.7% to
eliminate ‘flat’ in indicated N1
• New Throttle Interpolation Curves for New High Altitude Ratings
-New interpolation points used with new ratings in order to maintain thrust
sensitivity requirements
• Modification to Quick Windmill Relight EGT Redline Inhibit Logic
-Latches quick windmill relight timer threshold
+Prevents EGT redline inhibit once start determined not to be a quick windmill relight
+Addresses potential for erroneous redline indication during overtemperature events
• EGT Trim Logic
-Simplification to trim logic to aid in EGT trending
+Currently two EGT trim levels exist (takeoff and EOB)
+Proposed logic ties EGT trim to nameplate allowing for one EGT trim level
-Elimination of DAC Shunt for 7B27B1 Rating
13
Six Sigma -- Define/Measure/Analyze/Improve/Control Phases GE Aircraft Engines
GE Proprietary Information GE Aircraft Engines
g GE Aircraft Engines CFM56-7B EEC Software P22 Improvement
• EEC Table Pointer Corruption Accommodation
-Three Confirmed CFM56-7B LOTC Events Related to Pointer Corruption
-Demonstrated in the CFM56-7B Fuel Systems Test Cell
-All Table Pointers Will Be Limit Checked Before Being Used
• TRA Selection Logic Update
-In the Presence of Specific Failures the EEC Will not Lock-out the TRA Signals Until
the Engine has Reached Idle
+Prior to 7.B.O the EEC will lock out the TRA anytime both TRA signals are not available
• FMV-Resolver Limits Extended
-7.B.O FMV Resolver Limits Will Account For Variations in Temperature
+Reduce the Number of FMV-Signal-Out-Of-Range Faults
+Message 73-x034y (Drives the Engine Control Light)
• AEW&C Oil Pressure Logic
-Unique Oil Pressure By-pass Valve on AEW&C Engines
-By-Pass Valve Failure Detection Logic Modification
• CFM56-7 SB 73-084 Available Dec 02
14
Six Sigma -- Define/Measure/Analyze/Improve/Control Phases GE Aircraft Engines
GE Proprietary Information GE Aircraft Engines
g GE Aircraft Engines Z Score For Missing P20 Software
Description: Classify units as defective or non defective, traditionally uses the Binomial distribution formula listed below.
Glossary: Mean Average
Sigma Standard Deviation
p(d) Probability of Defects
Enter Numbers Below
Formulas: p(d)= No. of Bad Units "=>" 8 p(d)= 0.133333
Total No. of Units 60
Enter Numbers Above
p(d) = 1-FTY "=>" 0.133333
Z = 1.11077
FTY= 0.866667
15
Six Sigma -- Define/Measure/Analyze/Improve/Control Phases GE Aircraft Engines
GE Proprietary Information GE Aircraft Engines
g GE Aircraft Engines Z Score For Missing P21/P22 Software
Description: Classify units as defective or non defective, traditionally uses the Binomial distribution formula listed below.
Glossary: Mean Average
Sigma Standard Deviation
p(d) Probability of Defects
Enter Numbers Below
Formulas: p(d)= No. of Bad Units "=>" 60 p(d)= 1
Total No. of Units 60
Enter Numbers Above
p(d) = 1-FTY "=>" 1
Z = #NUM!
FTY= 0
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Six Sigma -- Define/Measure/Analyze/Improve/Control Phases GE Aircraft Engines
GE Proprietary Information GE Aircraft Engines
g GE Aircraft Engines
 ATA Powerplant Engineering verbally committed to
incorporate P22 (latest software) once it is released
 ATA understands the risks with not incorporating P20 &
P21 software
 Can avoid many engine problems and in-service issues
(as demonstrated by Airline examples)
 Once software is released, will inform ATA Powerplant
Engineering to issue Engineering Order
 Will educate ATA line planning group to incorporate latest
EEC software in the fleet
 Will monitor engine issues due to delay in incorporating
EEC software improvement (until P22 is incorporated)
 After P22 release, add item to weekly Airline Fleet Review
meeting to monitor progress and issues (VP exposure)
Control – Summary

979199501

CFM56-7B TRAINING MANUAL ENGINE FAN TRIM BALANCE

testuser

谢谢，辛苦了！

且行

 

kinran

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Six Sigma Project CFM56-7B EEC Software Improvement at ATA

lazybone9988

好的资料！好的资料！

控制初学者1

Six Sigma Project CFM56-7B EEC Software Improvement at ATA

mengkyq

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