FROM: THE BOEI NG COMPANY TO : Boeing Correspondence (MOM} [MESSAGE

**NUM BER:MOM-~** ...101\.1 -13- 0137 - 01B] Mul ti Operator Message MESSAGE DATE: 21 F e b 2013 1 4-22 US PAC IFIC TIME / 21 Feb 2013 2222 GMT This message is sent to all 777 m ode l Boeing Field Service ba ses for onward transmittal to the operator with a copy to R eg ion al Directors. SERVICE REQUEST ID: 2-2385941676 ACCOUNT: DUE DATE: PRODUCT TYPE: PRODUCT LINE: PRODUCT: ATA: Bo eing Correspondence (MOM} 06 -May-2013 23 : 59

**Aiq~lane** 777 777 -20 0 5753 -00 SUBJECT: Action - O utboard Aft !=lap Track Attach men t Failure of the Inboard Flap REFERENCES: 

## IA/ 777 -FTD-57 - 12002 /B/ 777-SRP-57 -0258 /C/ Lug Fitting Failure a nd Bushing Con f igurat ion /D/ Typical Dama ge /E/ Inspection Procedure SUMMARY: This message informs operators of four (4} reported failures at the forward attachment causing the 113W2556 Outb o a rd Aft Fl ap T racj{ sepa ration from the 113W2100 Inboard Main Flap and resulting in

. additional collat eral structu ral d ;;;mage. Also, provides inspection recommendation to assist operators in finding the condi ti o n prior to

**~he** fai lure. The advance information herein will assist operators in planning for imp end;n:;

**in rJE'cti**  **cr;** '1 nd rE\No rk effort
.
DESCRIPTION: Four 777 operat ors reported four (tJ} cases of the 113W 2556 track separating from the 113W2100 main flap. In all case s, the IL'g of the J.13W2655 suppcrt fitting failed at the forward attached point of 113W2556 trac k to th e 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} even ts are as

**f-:11!ov.:~** -1st event on 77 7 -300ER with 30963 

## I 5987 FH/FC on RH wing -2nd event on 777-300 with 20 313 / 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 o n RH wing

### One of the above operators has started a fleet wide inspectiG t' l of 18 ,;i r p!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 w i ng The above reports all occurred on flap configurations delivered after Ime 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 fitt ing at L/N 42Z a<. f,-;l lows (See Ref /C/): -On the 777-300ER,-200LR 

### & -F, was due to the higher loads requirer 1 e nts. -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 inu rn fitti ngs :evea!ed that the fracture originating from corrosion pits on the bore surface and p ropagated b•; fat igue 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 irtt erim inspections, rework or replacement instructions of the existing 113W2655 aluminum fitting s, 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.1si der accompl i sh 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 firs t: Operators should consider DVI and HFEC inspections on the 113W26 55 fit ting lug in situ using the following steps: Please see Ref /E/ attachment. 

### 1. Extend the flaps to detent 30, to provide access for inspection. Thi s wil l prevent any disassembly of the joint. 2. Inspect forward and aft of the bore hole on both the inbo ard and outboard faces. 3. HFEC inspected per 777 NDT manual Part 6 with a straight blade probe for cracks777 a irplanes t hat ha ve exc eed ed t l: e th re sho l d are at i ncre ased risk of a failu re event . Operators should consider ac co m pl ish HFE C in spe ctio n as ear ly as po s sib l e at ne xt scheduled maintenan ce check
. Operators that accom p li sh th e i n sp e ct ion s a nd/o r repla ce ment of fitting with bushings will receive credit for accom pl i shi ng t h e Servic e Bull etin when it is complete. Boeing i s ve ry in teres te d i n th e 1· es ults of the i ns p ect io n from the fleet, so we are requesting the operator to prov i d e a summary of t he re su lts t o suppo rt further investigation Necessary Actio n s F o ll o w i n g I n spectio n :

**===== ===**  **== ===~==**  **==== ==·=-=** 
**== ==**  **== =**  A. Crack Indicati ons : 1. Please, report any h d i n g s to Soe i ng i n cl ud i ng d at um a ircraft information, flap assembly serial number, subje ct f ittin g d 3:, h nu mh e r , and de t ect e d crack length to support investigation
. 2. Repl ace fittin g befc-re fu rth e r

**fli 1ts** 

**.** a. Remove and re p la ce t he 113 W2 G 55 pe r c' raw i ng an d SRM requirements
. 3. Contact Boei n g f or f urther inst ·· u ct i e> ns . 4. The 113W26 55 - 5 /6 Opp f itt i n g; ,viii b e ava ilable o n 26 Feb 2013 from Boeing Spares
. . a . Order two (2 ) BACB2 8A U7 B 0 17C b us hin gs . b
. Reset inspe ct i o n

**hr~s ho**  **d** t o 

### J

**~SO** DY/4000 F C

, wh ' ch ev er occurs first and repeat inspection interval of 365 DY/800 F C

, w hic h ever 

### oc u1; ,

**fir~ t:**  5. The new 113\11/ 265 5- 7/ - 3 O pp t't < m: u m fi t t in g w i ll b e av a ilable in the 113W2655-9/-10 Substitution Kit with tw o (2) BACB 28 ti. U7£'·017

**:·· ~>l**  **'ings**

**.** a . Status of avai labi li ty wi ll b e prov i ded i n Re f /A/ F TD. b. Terminate act io n-

**Jo** f urtl 'e;· i :-soe ction requ ired
B
. Bushing Migrat ion: 

### 1. Please , re p ort -c ny fr cl iro g)

**c** 

### ? r ,,. ·, ,g i nc'• J di rg

**~ur n**  a irc raft information , flap assembly serial number, and su b ;ect f i tt ir3 d asl " 11 1 mfJ':r to suppo rt i nve s tigation. 2
. Continued o per at ic•1 m < IY he

**::.~u·pt**
**le** w it h app l ' cat i on of CIC to bushing flange and lug surface until ne xt he avy ma int e n an:: e r 1 wck 11 1

**i~'**

**· ·;**  **Iern enta** 

**l** visua l inspect ions . a . Advi ce Bo e i n g of f i n d i n 5s fa" fL';!her actio n. b
. At ne xt heavy

**milin**
**~e nu~**  **r~~':.** b u shing s w ill n ee d t o be removed and replaced
. 3
. Repeat H FEC in sp ect io n of 36 C: ['V 

### '80 0 FC wh ic hev e r occ u rs first. C. Cracked S e al c ll l t .ll
.rot' rd

**~' 1'r**  

# =· 1. Continued o pe ratio n i s acce pt a b l e w ith ap p l i catio n of CIC to bushing flange and lug surface. a . Apply CIC per 777

**\~!li\/1** 5 1 . -2 11 

## r" to bu sh in g

**a;--**
**~** an d lug su rface
.2
. Repeat HFEC inspection of 365 DY/800 FC, w hich ever occur_; f irst.
D
. No Discrepant Condition Found: 

### 1. No additional rework is required. 2. Repeat HFEC inspection of 365 DY 

## I 800 FC, whichever occu rs fir st . E
. Lug Rework Limits: 1
. Operators may rework the lug holes 113W2655 fitting up to 0
.060 inc h diameter from drawing dimensions with Penetrant inspection, but the inspection th res hol d will not be reset. a . Please coordinate rework with Boeing on a case-by -cas e basis.
We thank the operators in advice for their support and appre ciate their pati ence in t hi s matter. We know this is a very important issue with the 777 operators, so pl ease 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