FROM: THE BOEI NG COMPANY 

TO : Boeing Correspondence (MOM} 

[MESSAGE NUM BER:MOM-~ ... 101\.1-13-0137-01B] Multi Operator Message 

MESSAGE DATE: 21 Feb 2013 14-22 US PACIFIC TIME / 21 Feb 2013 2222 GMT 

This message is sent to all 777 mode l Boeing Field Service bases for onward transmittal to the operator 

with a copy to Regional Directors. 

SERVICE REQUEST ID: 2-2385941676 

ACCOUNT: 

DUE DATE: 

PRODUCT TYPE: 

PRODUCT LINE: 

PRODUCT: 

ATA: 

Boeing Correspondence (MOM} 

06 -May-2013 23:59 

Aiq~lane 

777 

777-200 

5753-00 

SUBJECT: Action - Outboard Aft !=lap Track Attach ment Failure of the Inboard Flap 

REFERENCES: 

I A/ 777 -FTD-57 -12002 

/B/ 777-SRP-57-0258 

/C/ Lug Fitting Failure and Bushing Configuration 

/D/ Typical Damage 

/E/ Inspection Procedure 

SUMMARY: 

This message informs operators of four (4} reported failures at the forward attachment causing the 

113W2556 Outboard Aft Flap Tracj{ sepa ration from the 113W2100 Inboard Main Flap and resulting in 

. additional collateral structu ral d;;;mage. Also, provides inspection recommendation to assist operators in 

finding the condi tion prior to ~he fai lure. The advance information herein will assist operators in 

planning for impend;n:; in rJE'cti cr; '1 nd rE\No rk effort. 

DESCRIPTION: 

Four 777 operators reported four (tJ} cases of the 113W2556 track separating from the 113W2100 main 

flap. In all cases, the IL'g of the J.13W2655 suppcrt fitting failed at the forward attached point of 

113W2556 track to the main fla p Please s·=:e Ref /C/ attachment. Additional collateral damage was 

found to the mai n flap, aft flap oi!'d 2ft fla p drive mecha nisms. Please see Ref /D/ attachment. 

The four (4} events are as f-:11!ov.:~ 

-1st event on 777-300ER with 30963 I 5987 FH/FC on RH wing 

-2nd event on 777-300 with 20313 / 8322 FH/FC on LH wing 

- 3rd event on 777-300 with 31940 i 8471 FH/FC on LH wing 

-4th event on 777-300ER with 308J.4 I 5919 FH/FC on RH wing 
One of the above operators has started a fleet wide inspectiGt' l of 18 ,;irp!anes and has found two (2) 

additional fittings with small cracks in the lug bore: 

-1st report on 777-300 with 29292/7885 FH/FC on LH wing 

-2nd report on 777-300 with 29362/7801 FH/FC on LH wing 

The above reports all occurred on flap configurations delivered after I me number 423. In each case, the 

lower lug of the 113W2655 fitting had a split bushing arrangement. 

The joint between the 113W2655 fitting and 113W2556 track were redE:s igned by changing to split 

bushings from nested bushings in the 113W2655 fitting at L/N 42Z a<. f,-;l lows (See Ref /C/): 

-On the 777-300ER,-200LR & -F, was due to the higher loads requirer 1ents. 

-On the 777-200, -200ER & -300, was due to an option for production crnmonalit~'· 

Boeing Action: 

-------------- --------------

The Ref /B/ economic SRP was initiated on 24 Oct 2012. 

Boeing completed fracture analysis on three (3) failed alurn inurn fittings :evea!ed that the fracture 

originating from corrosion pits on the bore surface and propagated b•; fatigue prior to final ductile 

separation. 

For production, Boeing incorporated new fittings 113W2655-7/-8 made from titanium material with split 

bushing configuration beginning TBD. 

For Retrofit, Boeing plans to release a Service Bulletin that wi ll include irtterim inspections, rework or 

replacement instructions of the existing 113W2655 aluminum fittings, ECD TBD. 

Flaps delivered on aircraft from L/N 1 to L/N 422 are not affected at this time since these flaps have the 

lower lug of the 113W2655 fitting with a nested bushing configuration. 

DESIRED ACTION: 

For 777 airplanes delivered after line number 423, operators should c.c.1sider accompl ish ing inspection 

on airplanes that have accumulated 4000 FC or 1460 DY since delivery, whichever occurs first, and 

repeat inspection of 365 DY / 800 FC, whichever occurs first: 

Operators should consider DVI and HFEC inspections on the 113W2655 fitting lug in situ using the 

following steps: Please see Ref /E/ attachment. 

1. Extend the flaps to detent 30, to provide access for inspection. This wil l prevent any disassembly of 

the joint. 

2. Inspect forward and aft of the bore hole on both the inboard and outboard faces. 

3. HFEC inspected per 777 NDT manual Part 6 with a straight blade probe for cracks 
777 airplanes t hat have exceeded tl:e th reshold are at increased risk of a failu re event. Operators should 

consider accompl ish HFEC inspection as early as possible at next scheduled maintenance check. 

Operators that accom plish the inspections and/or repla cement of fitting with bushings will receive 

credit for accom pl ishi ng t he Service Bulletin when it is complete. 

Boeing is very interested in the 1·es ults of the inspection from the fleet, so we are requesting the 

operator to provide a summary of the results to suppo rt further investigation 

Necessary Actions Following Inspectio n: 

===== === == ===~== ==== ==·=-= == == == = 

A. Crack Indications : 

1. Please, report any h dings to Soe ing includ ing datum aircraft information, flap assembly serial 

number, subject fitting d3:,h nu mher, and det ected crack length to support investigation. 

2. Replace fitting befc-re fu rther fli 1ts . 

a. Remove and replace the 113W2G55 per c' rawing and SRM requirements . 

3. Contact Boeing for further inst··uctie> ns. 

4. The 113W2655-5/6 Opp fitting; ,viii be available on 26 Feb 2013 from Boeing Spares .. 

a. Order two (2) BACB28AU7B017C bushings. 

b. Reset inspection hr~s ho d to J ~SO DY/4000 FC, wh 'chever occurs first and repeat inspection interval 

of 365 DY/800 FC, whichever oc u1; , fir~ t: 

5. The new 113\11/2655-7/ -3 Opp t't<m:um fitting will be available in the 113W2655-9/-10 Substitution Kit 

with two (2) BACB28ti.U7£'·017 :·· ~>l 'ings . 

a. Status of avai labi lity wi ll be provided in Ref /A/ FTD. 

b. Terminate action- Jo furtl'e;· i:-soection required 

B. Bushing Migration: 

1. Please, report -c ny fr cl irog) c ?r,,.·,,g inc'• Jdirg ~urn aircraft information, flap assembly serial 

number, and su b;ect fittir3 dasl" 11 1 mfJ':r to support investigation. 

2. Continued operatic•1 m<IY he ::.~u·pt le wit h app l'cation of CIC to bushing flange and lug surface until 

next heavy maintenan::e r 1

wck 111 i~' · ·; Iern enta l visua l inspections. 

a. Advice Boeing of findin5s fa" fL';!her action. 

b. At next heavy milin ~e nu~ r~~':. bushings will need t o be removed and replaced . 

3. Repeat HFEC inspection of 36 C: ['V '800 FC wh ichever occurs first. 

C. Cracked Seal clll t .ll.rot'rd ~' 1'r =· 

1. Continued ope ration is acce ptable with ap plicatio n of CIC to bushing flange and lug surface. 

a. Apply CIC per 777 \~!li\/1 51

.-211 r" to bushing a;-- ~ and lug surface . 
2. Repeat HFEC inspection of 365 DY/800 FC, whichever occur_; first. 

D. No Discrepant Condition Found: 

1. No additional rework is required. 

2. Repeat HFEC inspection of 365 DY I 800 FC, whichever occu rs first . 

E. Lug Rework Limits: 

1. Operators may rework the lug holes 113W2655 fitting up to 0.060 inch diameter from drawing 

dimensions with Penetrant inspection, but the inspection threshold will not be reset. 

a. Please coordinate rework with Boeing on a case-by-case basis. 

We thank the operators in advice for their support and appreciate their patience in t his matter. 

We know this is a very important issue with the 777 operators, so please coo rdinate with your assigned 

customer. 

Steve Wirth Fleet Support Engineering- Structures 

Patrick s·chirmer 

Director- Customer Support Engineering 

Customer Support 

Commercial Aviation Services 

The Boeing Company