12_VBV System[1].pdf

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VBV System

CFM International Proprietary Information

The information in th is document is CFM Proprietary Information and is di sclosed in con fidence. It is the property of CFM

International and its p arent companies, GE and Snecma (SAFRAN Group), and shall n ot be used, di sclosed to o thers or

reproduced without th e express written consent of CFM. If consent is given for reprodu ction in whol e or in part, thisnotice shall appear in any such reproduction i n whole or in part. The information contained in th is document may also be

controlled b y the U.S. and French export control laws. Unauthorized export or re-export is proh ibited

Lisbon A320/CFM56-5/5B Focus Team Conference

June 2012



CFM International Proprietary Information subject to the restrictions on the cover of this presentationCFM, CFM56, LEAP56, LEAP-X and the CFM logo are trademarks of CFM International, a 50/50 joint company between Snecma and GE 2Lisbo n CFM56-5ABC Focus Team Ju ne 2012

Background




Fleet data

• VBV issue can lead to operational events including ATB & ATO

– 9 ATOs & 9 ATBs on the 5B fleet through May 2012 – Fleet disruptions related to EGT shift, Compressor Vane E/W or fuel

leak at the gear motor location

• Main on-wing discrepancies reported – Ball screw actuators (master or slave actuators) hard to rotate

– Stop mechanism seized

– Flex shaft (main or slave) broken

– Gear Motor




Distribution of removed components

• Detail of component removals

– 5A/B engines

– Based on data supplied to CFM – since 2009

• Gear Motor, Stop Mechanism and Flexshafts are the most removed VBVcomponents

– About 85% of the total removals

0

20

40

60

80

100

120

140

160

180

Gear motor Flex Shaft Stop mec RVDT Slave Act Master Act Main flexshaft

VBV components removed since 2009 (Quantity)




VBV system event contributors 2011

13; 25%

12; 23%

12; 23%

5; 9%

5; 10%

5; 10%

Répartition par cause racine(quantité ; pourcentage)

Gear Motor

Stop Mechanism

Flexible Shaft

Slave Actuator

Position Sensor

Master Actuator

Defective components ( 2011 events)Quantity; percentage

Gear Motor, Stop Mechanism and Flex shafts contribute to 71% of the VBV

related events




Analysis

• Stop mechanism

• CFM/Honeywell Root Cause analysis on-going• Major observations from investigations:

• Nut seized on screw

• Fretting damage to screw threads

• Bearings difficult to rotate / seized

• Significant Lack of grease

• Flexible shaft• Typically a secondary damage of ballscrew actuators hard to rotate• Several cases reported without findings on the other VBV components

• Gear motor• suffering from the kinematics getting harder to actuate, also from pollution within the fuel.

• CFM addit ional preventive maintenance recommendation:

– CFM recommends to apply the SB 75-0043 - regreasing of master and slaveactuators - to relief VBV system.

Re-greasing procedure will improve the VBV system kinematics




liquez pour modifier le style

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>>Regreasing p roc edure of Master and Slave actuators

SB 75 0043

7This document is a Bullet Point presentation. It may be misinterpreted without the proper comments from an appropriate CFM representative.




Ballscrew on-wing regreasing procedure – SB 75-0043

• On-wing regreasing procedure

– Approved & Issued early May 2012 – Master and slave ballscrew actuators concerned

– Regreasing reduces the actuation torque of the complete VBV system

• Full efficiency if 1st regreasing prior to 3000FH then every 3000FH

– Appropriate tooling supplied by Honeywell





• Procedure sequence

– Get access to VBV doors (11 slaves & 1 master)

– Prepare Mobil 28 grease hand pump

– Localize grease fitting hole of each door & clean it – Apply 0,1 Oz (2,8 g) via the grease fitting hole

– Actuate VBV system from 2 O’clock door at least 3 timesopen / close to distribute grease into ballscrews – makesure system operates smoothly & freely

– Perform RVDT rigging & MCDU check





• Procedure feedback (tested with operators in April 2012)

– Doors near 12 o’clock position are the most difficult to get access to. If possible thrust

reverser cowls should be fully deployed – Mirror shall be used in this area

– Amount of grease shall be measured pending on customer own tooling

– 4 hours with 2 mechanicsMirror to help fitting

greasing holeGreasing gun




Regreasing experience

• TAM Fleet: 184 Engines – 2000 FH to 22000 FH

• Implemented the regreasing procedure via EngineeringOrder 2 years ago into their Fleet ( 2000- 22000FH)

– No VBV-ballscrew-event reported since.




Regreasing experience

CFM would like to thank all operators for theirsupport during the development of this procedure





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>>Troub lesho ot ing improvem ents





Troubleshooting modifications

• Objective: Improve the on-wing troubleshooting in case of VBV issue

Operate VBV manually

Y

NCheck resistance

/ RVDT/J8/HMU

Hard to rotate?

Remove/Insp/replace flexshafts

damaged

Operate each VBV slave doors

manually/ replace any suspect

Remove GM/SM assy

Operate GM/ freely?

Operate SM/ freely?

Operate master door/ freely?

replace

replace

replace

Inspec Main flexshaft

Current

Operate VBVwith tooling at Master

door position/ mesure the torque

Y

N

Check resistance

/ RVDT/J8/HMU

Torque > CMM

limit?

Remove/Insp/replace flexshaftsdamaged

Operate each VBV slave doors

manually/ replace any suspect

Remove GM/SM assy

Operate SM/ freely?

Operate GM/ freely?

replace

replace

Inspec Main flexshaft

Proposal draft

T/S Gear motor &Stop mechanism

first

New T/S will reduce the time needed by testing of gear motor and stop

mechanism first.

Under

Evaluation




Troubleshooting modifications

• Perform T/S of Gear Motor and Stop Mechanism as first T/S operations

– Main advantage :

First component inspected are the most removed one decreasing the timespent for T/S

• Development of a system torque check

procedure (after removal of GM and SM)

• Introduction of a torque key in the Masterballscrew Socket to measure the actuation

torque of the system

• Maintenance Torque limits to be defined

• Maintenance limits defined and to be

substantiated

Trouble Shooting procedure update expected 4Q12





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>>Maintenance pro pos i t ion to reduce VBV sys tem

related events





Fleet status, prediction and go forward

• Based on above Weibulls, CFM evaluates a soft time for the VBV system

at 15,000hrs, 2nd C-check

No Maintenance

Overhaul at SV

Soft time

implementation

10,000 hrs /15,000 hours




Fleet status, prediction and go forward

• Introduction of soft time scheduled for sept. 2012 – Service Bulletin Cat. 7

• Pending efficiency of re-greasing procedure, CFM propose implementation of15,000 hrs threshold for VBV System Preventive Maintenance

• Recommendation to be updated with CFM56-5B fleet re-greasing feedback




Summary

• CFM recommends VBV system overhaul at SV (SB 75-0032, cat 3)

• CFM recommends application of re-greasing to the ball screw actuatorsusing SB 75-0043, cat 7

• CFM proposes a modification to the VBV system Trouble shooting.

Available by 4Q12

• Based on actual and predicted fleet data, CFM recommends a soft time at15000 hours, in order to decrease the amount of VBV system relatedevents

– Availability by September 2012 – to be updated with CFM56-5B fleet re-greasing feedback




QUESTIONS / DISCUSSION



CFM International Proprietary Information subject to the restrictions on the cover of this presentationC C C fC / S G 21Lisbo n CFM56-5ABC Focus Team Ju ne 2012

The information in this document is CFM Proprietary Information and is disclosed in confidence. It is the property of CFM International and its parent companies, General Electric and Snecma, Safran

group and shall not be used, disclosed to others or reproduced without the express written consent of CFM. If consent is given for reproduction in whole or in part, this notice shall appear in any such

reproduction in whole or in part. The information contained in this document may also be controlled by the U.S. and French export control laws. Unauthorized export or re-export is prohibited

This document is a Bullet Point presentation. It may be misinterpreted without the proper comments from an appropriate CFM representative.

Documents

12_VBV System[1].pdf