### Commercial **Airplanes** 

# 777 Service Bulletin **ALERT Number: 777-53A0043**  Original Issue: November 09, 2011 ATA System: 5315 5335 5355 **SUBJECT:** FUSELAGE - Skin Panels - Skin Lap Splice Inspection for Fatigue Cracks at Maskant Trim Scribe Lines Export of this technology is controlled under the United States Export Administration Regulations (EAR) (15 CFR 730-774). An export license may be required before it is used for development, production or use by foreign persons from specific countries. The controller of this data has the individual responsibility to abide by all export laws. 9E991 ECCN: 

## BOEING PROPRIETARY, CONFIDENTIAL, AND/OR TRADE SECRET Copyright © 2011 The Boeing Company Unpublished Work - All Rights Reserved Boeing claims copyright in each page of this document only to the extent that the page contains copyrightable subject matter. Boeing also claims copyright in this document as a compilation and/or collective work. This document includes proprietary information owned by The Boeing Company and/or one or more third parties. Treatment of the document and the information it contains is governed by contract with Boeing. For more information, contact The Boeing Company, P.O. Box 3707, Seattle, Washington 98124. Boeing, the Boeing signature, the Boeing symbol, 707, 717, 727, 737, 747, 757, 767, 777, 787, Dreamliner, BBJ, DC-8, DC-9, DC-10, KC-10, KDC-10, MD-10, MD-11, MD-80, MD-88, MD-90, P-8A, Poseidon and the Boeing livery are all trademarks owned by The Boeing Company; and no trademark license is granted in connection with this document unless provided in writing by Boeing.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: November 09, 2011 777-53A0043 1 of 28 3.0BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: November 09, 2011 777-53A0043 2 of 28 **BOEING SERVICE BULLETIN 777-53A0043 ALERT**  **ALERT**

BLANK PAGE**Table of Contents** Summary...................................................... 5 1. PLANNING INFORMATION ........................................ 9 A. Effectivity................................................ 9 1. Airplanes............................................. 9 2. Spares Affected . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 B. Concurrent Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 C. Reason . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 D. Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 E. Compliance. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 F. Approval . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 G. Manpower . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 H. Weight and Balance Changes. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 I. Electrical Load Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 J. References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 1. Existing Data. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 2. Data supplied with this Service Bulletin. . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 3. Installation Drawings Used in the Preparation of this Service Bulletin. . . . . . . . . . . . 15 K. Publications Affected . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 L. Interchangeability and Intermixability of Parts . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 2. MATERIAL INFORMATION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 A. Material - Price and Availability. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 B. Industry Support Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 C. Parts Necessary For Each Airplane. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 1. Kits/Parts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 2. Parts and Materials Supplied by the Operator. . . . . . . . . . . . . . . . . . . . . . . . 17 3. Parts Modified and Reidentified. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 4. Parts Removed and Not Replaced . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 D. Parts Necessary to Change Spares. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 E. Special Tooling - Price and Availability. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 F. Special Tooling Necessary to do this Service Bulletin. . . . . . . . . . . . . . . . . . . . . . . 17 3. ACCOMPLISHMENT INSTRUCTIONS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 A. GENERAL INFORMATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 B. WORK INSTRUCTIONS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 FIGURE 1: AFFECTED SECTION 41 LAP SPLICES. . . . . . . . . . . . . . . . . . . . . . . . . . . 22 FIGURE 2: AFFECTED SECTION 43 AND SECTION 44 LAP SPLICES [Group 1]. . . . . . . . . . . 24 FIGURE 3: PHASED ARRAY ULTRASONIC LAP SPLICE INSPECTION . . . . . . . . . . . . . . . . 26

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: November 09, 2011 777-53A0043 3 of 28 **BOEING SERVICE BULLETIN 777-53A0043 ALERT**  **ALERT**BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: November 09, 2011 777-53A0043 4 of 28 **BOEING SERVICE BULLETIN 777-53A0043 ALERT**  **ALERT**

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### Commercial **Airplanes** 

# 777 Service Bulletin **ALERT Summary**  **Number: 777-53A0043** Original Issue: November 09, 2011 ATA System: 5315 5335 5355 **SUBJECT:** FUSELAGE - Skin Panels - Skin Lap Splice Inspection for Fatigue Cracks at Maskant Trim Scribe Lines THIS BULLETIN IS SENT TO THE OPERATORS OF RECORD OF THE AIRPLANES SHOWN IN PARAGRAPH 1.A., EFFECTIVITY. IF AN AIRPLANE HAS BEEN LEASED OR SOLD, SEND THIS SERVICE BULLETIN TO THE NEW OPERATOR. IF APPLICABLE SPARES HAVE BEEN SOLD, SEND THIS SERVICE BULLETIN TO THE NEW OWNER. **CONCURRENT REQUIREMENTS** None. **BACKGROUND** This service bulletin gives instructions for the inspection and repair of fatigue cracks at scribe lines in the fuselage skin at certain lap joints in Section 41, Section 43 and Section 44. Fatigue cracks can develop in the skin at locations where scribe lines were made during production. Fatigue cracks in the skin that remain undetected could grow large and cause sudden decompression and the inability to sustain limit load. On affected airplanes, scribe lines may have been inadvertently made in the overlapped skin in lap joints if a sharp tool was used to remove the maskant from the clad aluminum skin panels during assembly of the affected lap joints. During the 777 fatigue test, lap joint cracks were found, and analysis indicated that those cracks initiated at scribe lines that were made during production when maskant was removed from the affected skin panels. Accomplishment of the inspections shown in this service bulletin will help make sure that fatigue cracks that can form in the fuselage skin at maskant trim scribe lines are found and repaired before they can become large and cause sudden loss of cabin pressure. Boeing Service Related Problem (SRP) 777-SRP-53-0165 is related to this service bulletin. This table is provided to operators for planning purposes only. Refer to the applicable sections for more information.
**Reference Affected**  **Planning Data** Paragraph 1.A.2., Spares Affected No Spares Affected Paragraph 1.E., Compliance Yes AD Related Paragraph 1.H., Weight and Balance Changes No Weight and Balance Change

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: November 09, 2011 777-53A0043 5 of 28**Reference Affected**  **Planning Data** Paragraph 1.I., Electrical Load Data No Electrical Load Changed Paragraph 1.K., Publications Affected No Publications Affected Paragraph 1.K., Publications Affected No Airplane Flight Operations Affected (Flight CrewOperations Manual and/or FAA Approved Airplane Flight Manual) Paragraph 2.C.1., Kits/Parts No Kits/Parts Required Paragraph 2.C.2., Parts and Materials Supplied by the Operator No Operator Supplied Material Paragraph 2.F., Special Tooling Necessary to do this Service Bulletin No Special Tooling Required

**ACTION (PRR 62777-56RS)** Do external ultrasonic inspections at certain skin lap splices for cracks in the overlapped skin. On Group 1 airplanes, affected lap splices are in Section 41, 43 and 44. On Group 2 airplanes, affected lap splices are only in Section 41. Where cracks are found, repair in accordance with this service bulletin. Where no cracks are found, repeat the inspection in accordance with this service bulletin. **EFFECTIVITY** 777-200 and 777-300 Airplanes. Refer to Paragraph 1.A.1., Airplanes, for the list of affected airplanes. **COMPLIANCE** The Federal Aviation Administration (FAA) will possibly release an Airworthiness Directive related to this service bulletin. The Airworthiness Directive will make the compliance tasks and times given in this service bulletin mandatory. Refer to Paragraph 1.E., Compliance. **INDUSTRY SUPPORT INFORMATION** Boeing warranty remedies are available for airplanes in warranty as of October 25, 2001. Please refer to Paragraph 2.B., Industry Support Information. **MANPOWER Elapsed Hours**  **Total Task Hours Airplanes**  31.5 126.0 Group 1 12.5 50.0 Group 2 Refer to Paragraph 1.G., Manpower. **MATERIAL INFORMATION** None.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: November 09, 2011 777-53A0043 6 of 28 **BOEING SERVICE BULLETIN 777-53A0043 ALERT**  **ALERT**BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: November 09, 2011 777-53A0043 7 of 28 **BOEING SERVICE BULLETIN 777-53A0043 ALERT**  **ALERT**BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: November 09, 2011 777-53A0043 8 of 28 **BOEING SERVICE BULLETIN 777-53A0043 ALERT**  **ALERT**

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### Commercial **Airplanes** 

# 777 Service Bulletin **ALERT Number: 777-53A0043**  Original Issue: November 09, 2011 ATA System: 5315 5335 5355 **SUBJECT:** FUSELAGE - Skin Panels - Skin Lap Splice Inspection for Fatigue Cracks at Maskant Trim Scribe Lines THIS BULLETIN IS SENT TO THE OPERATORS OF RECORD OF THE AIRPLANES SHOWN IN PARAGRAPH 1.A., EFFECTIVITY. IF AN AIRPLANE HAS BEEN LEASED OR SOLD, SEND THIS SERVICE BULLETIN TO THE NEW OPERATOR. IF APPLICABLE SPARES HAVE BEEN SOLD, SEND THIS SERVICE BULLETIN TO THE NEW OWNER. **1. PLANNING INFORMATION A. Effectivity**  1. Airplanes Refer to Service Bulletin Index D624W001 Part 3 for Airplane Variable Number, Line Number, and Serial Number data. This service bulletin is for the airplanes shown below. Refer to PRR 62777-56RS for data about this change.
**DESCRIPTION CONFIGURATION**  **GROUP** All 777-200 airplanes line number 1 - 75.

- 1 All 777-200 and 777-300 airplanes line number 76 - 104.

- 2

Airplane Models: 777-200, 777-300 **Group Variable Number**  1 WA001 - WA017 1 WA076 - WA080 1 WA086 - WA089 2 WA090 - WA092 1 WA101 - WA104

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: November 09, 2011 777-53A0043 9 of 28**Group Variable Number**  1 WA116 - WA119 1 WA131 - WA136 2 WA137 1 WA171 - WA175 1 WA196 - WA198 1 WA206 2 WA207 1 WA221 2 WA222 1 WB001 - WB008 2 WB009 1 WB051 - WB056 2 WB057 - WB062 1 WB101 - WB103 2 WB104 1 WB121 - WB122 1 WB131 - WB132 1 WB151 2 WB152 - WB153 1 WB161 - WB162 2 WB163 - WB164 1 WB181 2 WB182 - WB184 2 WB271 2 WB276 - WB279 2 WB501 - WB502 2 WB531 2. Spares Affected None. **B. Concurrent Requirements** None.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: November 09, 2011 777-53A0043 10 of 28 **BOEING SERVICE BULLETIN 777-53A0043 ALERT**  **ALERT C. Reason**  This service bulletin gives instructions for the inspection and repair of fatigue cracks at scribe lines in the fuselage skin at certain lap joints in Section 41, Section 43 and Section 44. Fatigue cracks can develop in the skin at locations where scribe lines were made during production. Fatigue cracks in the skin that remain undetected could grow large and cause sudden decompression and the inability to sustain limit load. On affected airplanes, scribe lines may have been inadvertently made in the overlapped skin in lap joints if a sharp tool was used to remove the maskant from the clad aluminum skin panels during assembly of the affected lap joints. During the 777 fatigue test, lap joint cracks were found, and analysis indicated that those cracks initiated at scribe lines that were made during production when maskant was removed from the affected skin panels. Accomplishment of the inspections shown in this service bulletin will help make sure that fatigue cracks that can form in the fuselage skin at maskant trim scribe lines are found and repaired before they can become large and cause sudden loss of cabin pressure. Boeing Service Related Problem (SRP) 777-SRP-53-0165 is related to this service bulletin. **D. Description** Do external ultrasonic inspections at certain skin lap splices for cracks in the overlapped skin. On Group 1 airplanes, affected lap splices are in Section 41, 43 and 44. On Group 2 airplanes, affected lap splices are only in Section 41. Where cracks are found, repair in accordance with this service bulletin. Where no cracks are found, repeat the inspection in accordance with this service bulletin. **NOTE:** This service bulletin is similar to Boeing Service Bulletin 777-53A0054, "Fuselage - - Body Station 132.5 to Body Station 2150 - External Inspection of the Fuselage Skin for External Scribe Lines, " but it does not replace Service Bulletin 777-53A0054. The cause of the scribe lines, the specific location of the scribe lines, and affected airplanes are different in this service bulletin than in Service Bulletin 777-53A0054. The work in this service bulletin is done in the maintenance zone(s) given below. **Group 1:**
**Affected Maintenance Zones Zone**  **Model** 117, 118, 121, 122, 123, 124, 125, 126, 221, 222, 223, 224, 231, 232, 233, 234, 243, 244 777-200

**Group 2:**
**Affected Maintenance Zones Zone**  **Model** 117, 118, 121, 122, 123, 124, 221, 222, 223, 224 777-200, 777-300

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: November 09, 2011 777-53A0043 11 of 28 **BOEING SERVICE BULLETIN 777-53A0043 ALERT**  **ALERT E. Compliance**  The Federal Aviation Administration (FAA) will possibly release an Airworthiness Directive related to this service bulletin. The Airworthiness Directive will make the compliance tasks and times given in this service bulletin mandatory. **Group 1: Table 1:Lap Splice Inspection - Section 41, 43 and 44**  **Repeat Interval (Not to Exceed)**  **Compliance Time (Whichever Occurs Later)**  **Action Condition** 

- Within 24 months afterthe original issue date on this service bulletin. Before 34,000total flight-cycles. Do external phased-array ultrasonic inspections of certain fuselage skin lap splices in Section 41, Section43, and Section 44 for cracks in accordance with Paragraph 3.A., General Information and Paragraph 3.B., Work Instructions, PART 1. All Airplanes

4,200 flight-cycles.

- Within 4,200flight-cycles after the previous inspection. Do external phased-array ultrasonicinspections of any affected, unrepaired lap splices for cracks in accordance with Paragraph 3.A., General Information and Paragraph 3.B., Work Instructions, PART 1. Where no crack is found.

- Before further flight. Repair in accordance with Para- graph 3.A., General Information and Paragraph 3.B., Work Instructions, PART 2. (a) Where any crack is found.

(a) No more inspections are necessary per this service bulletin in the repaired area. Do post-repair inspections in accordance with the applicable Structural Repair Manual, or other approved data. **Group 2: Table 2: Section 41 Lap Splice Inspection**  **Repeat Interval (Not to Exceed)**  **Compliance Time (Whichever Occurs Later)**  **Action Condition** 

- Within 24 months afterthe original issue date on this service bulletin. Before 34,000total flight-cycles. Do external phased-array ultrasonic inspections of certain fuselage skin lap splices in Section 41 for cracks in accordance with Paragraph 3.A., General Information and Paragraph 3.B., Work Instructions, PART 1. All Airplanes

4,200 flight-cycles.

- Within 4,200flight-cycles after the previous inspection. Do external phased-array ultrasonicinspections of any affected, unrepaired lap splices in accordance with Paragraph 3.A., General Informationand Paragraph 3.B., Work Instructions, PART 1. Where no crack is found.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: November 09, 2011 777-53A0043 12 of 28 **BOEING SERVICE BULLETIN 777-53A0043 ALERT**  **ALERT Group 2:**  **Table 2: Section 41 Lap Splice Inspection Repeat Interval**  **(Not to Exceed) Compliance Time (Whichever**  **Occurs Later) Action**  **Condition**

- Before further flight. Repair crack in accordance with Paragraph 3.A., General Informationand Paragraph 3.B., Work Instructions, PART 2. (a) Where any crack is found.

(a) No more inspections are necessary per this service bulletin in the repaired area. Do post-repair inspections in accordance with the applicable Structural Repair Manual, or other approved data. **F. Approval** This service bulletin was examined by the Federal Aviation Administration (FAA). The changes specified in this service bulletin comply with the applicable regulations and are FAA approved, as well as European Aviation Safety Agency (EASA)/Joint Aviation Authorities (JAA) approved for all EASA/JAA approved airplanes listed in the service bulletin effectivity. This service bulletin and its approval were based on the airplane in its original Boeing delivery configuration or as modified by other approved Boeing changes. If an airplane has a non-Boeing modification or repair that affects a component or system also affected by this service bulletin, the operator is responsible for obtaining appropriate regulatory agency approval before incorporating this service bulletin. **G. Manpower** The table below shows an estimate of the task hours necessary to do this inspection for each airplane. This estimate is for direct labor only, done by an experienced crew. Adjust the estimate with operator task hour data if necessary. The estimate does not include lost time. These are some examples of lost time: • Time to adjust to the workplace • Time to schedule the work • Time to inspect the work • Time to cure the materials • Time to make the parts • Time to find the tools. **Group 1: Table 1 - Phased Array Ultrasonic Inspection Method**  **Elapsed Hours Task Hours**  **Number of Persons Task**  7.00 28.00 4 Prepare 9.75 39.00 4 Inspect Section 41 (Figure 1 and Figure 3)

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: November 09, 2011 777-53A0043 13 of 28 **BOEING SERVICE BULLETIN 777-53A0043 ALERT**  **ALERT Group 1:**  **Table 1 - Phased Array Ultrasonic Inspection Method Elapsed Hours**  **Task Hours Number of Persons**  **Task** 14.75 59.00 4 Inspect Section 43and Section 44 (Figure 2 and Figure 3) 31.50 126.00 TOTAL FOR EACH AIRPLANE **Group 2: Table 2 - Phased Array Ultrasonic Inspection Method**  **Elapsed Hours Task Hours**  **Number of Persons Task**  2.75 11.00 4 Prepare 9.75 39.00 4 Inspect Section 41 (Figure 1 and Figure 3) 12.50 50.00 TOTAL FOR EACH AIRPLANE
**NOTE:** More time will be necessary for repairs if cracks are found. **H. Weight and Balance Changes** None. **I. Electrical Load Data** Not changed. **J. References** 1. Existing Data a. Engineering Change Memo PRR 62777-56RS b. Boeing Service Bulletin 777-53A0054 c. Boeing Service Letter 777-SL-51-013 d. Boeing Service Related Problem (SRP) 777-SRP-53-0165 e. Service Bulletin Index D624W001 f. 777 Aircraft Maintenance Manual (AMM) 51-21-01, 51-21-10, 51-31-01 g. 777 Non-Destructive Testing (NDT) Manual Part 4, 53-00-04 h. 777-200 Structural Repair Manual (SRM) 53-00-01

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: November 09, 2011 777-53A0043 14 of 28 **BOEING SERVICE BULLETIN 777-53A0043 ALERT**  **ALERT**i. 777-300 Structural Repair Manual (SRM) 53-00-01 2. Data supplied with this Service Bulletin None. 3. Installation Drawings Used in the Preparation of this Service Bulletin None. **K. Publications Affected** 1. Publications: None. 2. Damage Tolerance Based Structural Inspections: Boeing has evaluated the repairs and/or changes in this service bulletin for effects on Fatigue Critical Structure (FCS) and for changes to Damage Tolerance Inspections (DTI) required in the Maintenance Program. This service bulletin affects FCS but no new DTIs are necessary. **L. Interchangeability and Intermixability of Parts** Accomplishment of this service bulletin does not affect interchangeability or intermixability of parts.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: November 09, 2011 777-53A0043 15 of 28 **BOEING SERVICE BULLETIN 777-53A0043 ALERT**  **ALERT**BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: November 09, 2011 777-53A0043 16 of 28 **BOEING SERVICE BULLETIN 777-53A0043 ALERT**  **ALERT**

BLANK PAGE**2. MATERIAL INFORMATION A. Material - Price and Availability**  None. **B. Industry Support Information** Boeing warranty remedies are available for 777 airplanes in warranty as of October 25, 2001. For inspection task hour reimbursement for airplanes in warranty as of that date, send a warranty claim to Boeing Commercial Airplanes Group - Warranties. If the condition described in this service bulletin is found during the inspection for airplanes in warranty as of that date and additional task hours are required, send a warranty claim to Boeing Commercial Airplanes Group - Warranties. Please refer to this service bulletin number and reference the airplane variable numbers in your purchase order. **C. Parts Necessary For Each Airplane** 1. Kits/Parts None. 2. Parts and Materials Supplied by the Operator None. 3. Parts Modified and Reidentified None. 4. Parts Removed and Not Replaced None. **D. Parts Necessary to Change Spares** None. **E. Special Tooling - Price and Availability** None. **F. Special Tooling Necessary to do this Service Bulletin** No special tools or equipment are necessary to do the change in this service bulletin. But, maintenance and overhaul tools in the manuals given in Paragraph 1.J., References, can be necessary. Examine operator tool supply to make sure all necessary tools are available.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: November 09, 2011 777-53A0043 17 of 28 **BOEING SERVICE BULLETIN 777-53A0043 ALERT**  **ALERT**BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: November 09, 2011 777-53A0043 18 of 28 **BOEING SERVICE BULLETIN 777-53A0043 ALERT**  **ALERT**

BLANK PAGE**3. ACCOMPLISHMENT INSTRUCTIONS A. GENERAL INFORMATION**  **CAUTION:** KEEP THE WORK AREA, WIRES AND ELECTRICAL BUNDLES CLEAN OF METAL PARTICLES OR CONTAMINATION WHEN YOU USE TOOLS. UNWANTED MATERIAL, METAL PARTICLES OR CONTAMINATION CAUGHT IN WIRE BUNDLES CAN CAUSE DAMAGE TO THE BUNDLES. DAMAGED WIRE BUNDLES CAN CAUSE SPARKS OR OTHER ELECTRICAL DAMAGE. **NOTE:** 1. Manual titles are referred to by acronyms. Refer to Paragraph 1.J., References, for definition of the acronyms. 2. Obey all of the warnings and cautions given in the specified manual sections. 3. Unless shown differently, these dimensions and tolerances are used: – Linear dimensions are in inches – Tolerance on linear dimensions, other than rivet and bolt edge margins, is plus or minus 0.03 inch 4. Use the approved fastener and process material substitutions in accordance with SRM Chapter 51. 5. If the length of any fastener specified in this service bulletin does not meet installation standards given in SRM Chapter 51, then a fastener of the same specification, or an approved substitute, with a length which meets the installation standards given in SRM Chapter 51 may be used. In addition, washers may be installed for fastener grip length in accordance with SRM Chapter 51. 6. These work instructions refer to procedures included in other Boeing documents. When the words "refer to" are used and the operator has an accepted alternative procedure, the accepted alternative procedure can be used. When the words "in accordance with" are included in the instruction, the procedure in the Boeing document must be used. 7. Boeing Service Letter 777-SL-51-013, Damage Reporting and Repair Plan/Design Guidelines, is an acceptable procedure to request information from Boeing for additional structural repair instructions. The Service Letter describes what information must be provided to Boeing before a structural repair can be provided. 8. The instructions in Paragraph 3.B., Work Instructions and the figures can include operation of tools or test equipment. Boeing Engineering Tool Drawings, the Illustrated Tool and Equipment Manual, and the Special Tool and Ground Handling Drawing Index contain data on versions of the tools or test equipment that you can use. It is permitted to use replaced tools. It is not permitted to use superseded tools. 9. If it is necessary to remove more parts for access, you can remove those parts. If you can get access without removing identified parts, it is not necessary to remove all of the identified parts. Jacking and shoring limitations must be observed.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: November 09, 2011 777-53A0043 19 of 28 **BOEING SERVICE BULLETIN 777-53A0043 ALERT**  **ALERT B. WORK INSTRUCTIONS** 
1. **Group 1:** Do the inspections in PART 1 at the time given in Paragraph 1.E., Compliance, Table 1.
2. **Group 2:** Do the inspections in PART 1 at the time given in Paragraph 1.E., Compliance, Table 2. **PART 1 - EXTERNAL PHASED ARRAY ULTRASONIC INSPECTION** 1. Get external access to the affected fuselage skin lap splices in Section 41. Affected Section 41 lap splices are shown in FIGURE 1. **NOTE:** A fillet seal of BMS 5-142 was applied to the fuselage skin lap joints in Section 41 during production. Any fillet seals that are wider than 0.3 inch must be removed (using approved methods) before accomplishing the phased-array ultrasonic inspections in this service bulletin. Refer to 777 AMM 51-31-01 as an accepted sealant removal procedure. After inspection, reapplication of any removed fillet seal is optional. 2. **Group 1:** Get external access to the affected fuselage skin lap splices in Section 43 and Section 44. Affected Section 43 and Section 44 lap splices are shown in FIGURE 2. 3. Do an external phased array ultrasonic inspection of affected lap joints for cracks in the overlapped skin in accordance with FIGURE 3. **NOTE:** 1. The phased array ultrasonic inspection method does not require paint removal, and only requires removal of fillet seals that are wider than 0.3 inch. (Fillet seals were only applied during production to the lap splices in Section 41.) 2. Inspections at scribe lines are not required in lap splice areas where a repair exists that has a minimum of three rows of fasteners above and below the lap splice scribe line inspection location. 3. If a repair blocks the inspections required by this service bulletin and the repair does not have a minimum of three rows of fasteners above and below the lap splice scribe line inspection location, remove the repair and conduct the inspections required by this service bulletin. After the inspection is complete, install an approved repair that has a minimum of three rows of fasteners above and below the lap splice scribe line inspection location. 4. If a crack is found, repair before further flight in accordance with PART 2. **NOTE:** No more inspections are necessary in accordance with this service bulletin in repaired areas, however do post-repair inspections in accordance with the applicable structural repair manual or other approved repair method. 5. **Group 1:** If no cracks are found, put the airplane back to a serviceable condition. In any affected areas that have not been repaired, do the inspections in PART 1 at the time given in Paragraph 1.E., Compliance, Table 1.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: November 09, 2011 777-53A0043 20 of 28 **BOEING SERVICE BULLETIN 777-53A0043 ALERT**  **ALERT**6. **Group 2:** If no cracks are found, put the airplane back to a serviceable condition. In any affected areas that have not been repaired, do the inspections in PART 1 at the time given in Paragraph 1.E., Compliance, Table 2. **PART 2 - REPAIR** 1. Repair any crack that is found. Install a repair in accordance with 777-200 SRM 53-00-01 Repair 16 or 777-300 SRM 53-00-01 Repair 16 or other approved methods. **NOTE:** After repair in accordance with the structural repair manual, no more inspections are necessary per this service bulletin in the repaired area. Do post-repair inspections in accordance with the structural repair manual or other approved methods. 2. **Group 1:** Put the airplane back to a serviceable condition. In any affected areas that have not been repaired, do the inspections in PART 1 again at the time given in Paragraph 1.E., Compliance, Table 1. 3. **Group 2:** Put the airplane back to a serviceable condition. In any affected areas that have not been repaired, do the inspections in PART 1 again at the time given in Paragraph 1.E., Compliance, Table 2.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: November 09, 2011 777-53A0043 21 of 28 **BOEING SERVICE BULLETIN 777-53A0043 ALERT**  **ALERT FIGURE 1: AFFECTED SECTION 41 LAP SPLICES**  **(SHEET 1 OF 2)**

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: November 09, 2011 777-53A0043 22 of 28 **BOEING SERVICE BULLETIN 777-53A0043 ALERT**  **ALERT FIGURE 1: AFFECTED SECTION 41 LAP SPLICES**  **(SHEET 2 OF 2)**

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: November 09, 2011 777-53A0043 23 of 28 **BOEING SERVICE BULLETIN 777-53A0043 ALERT**  **ALERT This Figure applies only to: Group 1.** 

**FIGURE 2: AFFECTED SECTION 43 AND SECTION 44 LAP SPLICES (SHEET 1 OF 2)** 

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: November 09, 2011 777-53A0043 24 of 28 **BOEING SERVICE BULLETIN 777-53A0043 ALERT**  **ALERT FIGURE 2: AFFECTED SECTION 43 AND SECTION 44 LAP SPLICES**  **(SHEET 2 OF 2)**

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: November 09, 2011 777-53A0043 25 of 28 **BOEING SERVICE BULLETIN 777-53A0043 ALERT**  **ALERT FIGURE 3: PHASED ARRAY ULTRASONIC LAP SPLICE INSPECTION**  **(SHEET 1 OF 3)**

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: November 09, 2011 777-53A0043 26 of 28 **BOEING SERVICE BULLETIN 777-53A0043 ALERT**  **ALERT FIGURE 3: PHASED ARRAY ULTRASONIC LAP SPLICE INSPECTION**  **(SHEET 2 OF 3)**

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: November 09, 2011 777-53A0043 27 of 28 **BOEING SERVICE BULLETIN 777-53A0043 ALERT**  **ALERT**The step numbers shown below agree with the numbers shown in the circle symbols in the figure. The QTY numbers shown below are the number of parts necessary for each affected lap splice location.
**MORE DATA QTY**  **IDENTIFICATION NAME**  **TASK STEP**  Use the externalphased-array ultrasonic inspectionmethod in accordance with 777 NDT Part 4, 53-00-04. - - Fuselage Skin Lap Splice Inspect 1

**FIGURE 3: PHASED ARRAY ULTRASONIC LAP SPLICE INSPECTION (SHEET 3 OF 3)** 

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: November 09, 2011 777-53A0043 28 of 28 **BOEING SERVICE BULLETIN 777-53A0043 ALERT**  **ALERT**