### Commercial **Airplanes** 

# 707 Service Bulletin **ALERT Number: A3539**  Original Issue: April 26, 2013 ATA System: 5330 **SUBJECT:** FUSELAGE - Fuselage Skin - Inspection of the Fuselage Skin for Scribe Lines Export of this technology is controlled under the United States Export Administration Regulations (EAR) (15 CFR 300-774). 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 © 2013 Boeing. Unpublished Work. All Rights Reserved. Treatment of this document and its content is governed by contract with Boeing. Rights to use this document are licensed on a per aircraft basis and such rights may not be transferable. For more information, contact The Boeing Company. 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, KC-46, KDC-10, MD-10, MD-11, MD-80, MD-88, MD-90, P-8, Poseidon and Boeing liveries 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.

Original Issue: April 26, 2013 A3539 1 of 110 3.0Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 26, 2013 A3539 2 of 110 **BOEING SERVICE BULLETIN A3539 ALERT**  **ALERT**

BLANK PAGE**Table of Contents** Summary...................................................... 5 1. PLANNING INFORMATION........................................ 9 A. Effectivity................................................ 9 1. Airplanes............................................. 9 2. Spares Affected. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 B. Concurrent Requirements. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 C. Reason. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 D. Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 E. Compliance. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 F. Approval. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36 G. Manpower. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36 H. Weight and Balance Changes. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38 I. Electrical Load Data. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39 J. References. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39 1. Existing Data:. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39 2. Data Supplied with this Service Bulletin:. . . . . . . . . . . . . . . . . . . . . . . . . . . 39 3. Installation Drawings Used in the Preparation of this Service Bulletin:. . . . . . . . . . . 39 K. Publications Affected. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39 L. Interchangeability and Intermixability of Parts. . . . . . . . . . . . . . . . . . . . . . . . . . . 39 M. Software Accomplishment Summary. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39 2. MATERIAL INFORMATION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41 A. Material - Price and Availability. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41 B. Industry Support Information. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41 C. Parts Necessary for Each Airplane. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41 1. Kits/Parts:. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41 2. Parts and Materials Supplied by the Operator:. . . . . . . . . . . . . . . . . . . . . . . . 41 3. Parts Modified and Reidentified:. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41 4. Parts Removed and Not Replaced:. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41 D. Parts Necessary to Change Spares. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42 E. Special Tooling - Price and Availability. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42 F. Special Tooling Necessary to do this Service Bulletin. . . . . . . . . . . . . . . . . . . . . . . 42 3. ACCOMPLISHMENT INSTRUCTIONS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43 A. GENERAL INFORMATION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43 B. WORK INSTRUCTIONS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45 FIGURE 1: FUSELAGE - SKIN LAP JOINTS - INSPECTION [Group 1]. . . . . . . . . . . . . . . . . 58 FIGURE 2: FUSELAGE - SKIN LAP JOINTS - INSPECTION [Group 2]. . . . . . . . . . . . . . . . . 62 FIGURE 3: FUSELAGE - SKIN LAP JOINTS - INSPECTION [Group 3]. . . . . . . . . . . . . . . . . 66 FIGURE 4: FUSELAGE - SKIN LAP JOINTS - INSPECTION [Group 4]. . . . . . . . . . . . . . . . . 70 FIGURE 5: FUSELAGE - EXTERNAL APPROVED REPAIRS - INSPECTION [Group 1]. . . . . . . . 74 FIGURE 6: FUSELAGE - EXTERNAL APPROVED REPAIRS - INSPECTION [Group 2]. . . . . . . . 77 FIGURE 7: FUSELAGE - EXTERNAL APPROVED REPAIRS - INSPECTION [Group 3]. . . . . . . . 80 FIGURE 8: FUSELAGE - EXTERNAL APPROVED REPAIRS - INSPECTION [Group 4]. . . . . . . . 83 FIGURE 9: FUSELAGE - EXTERNAL FEATURES - INSPECTION [Group 1-4]. . . . . . . . . . . . . 86 FIGURE 10: FUSELAGE - SKIN LAP JOINTS, EXTERNAL APPROVED REPAIRS, AND EXTERNAL FEATURES - NON-DESTRUCTIVE TESTING INSPECTIONS [Group 1-4]. . . . . . . . 89

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 26, 2013 A3539 3 of 110 **BOEING SERVICE BULLETIN A3539 ALERT**  **ALERT**FIGURE 11: FUSELAGE - SKIN LAP JOINTS, EXTERNAL APPROVED REPAIRS, EXTERNAL FEATURES, SKIN BUTT JOINTS AND DECALS - INSPECTION [Group 5]. . . . . . . . . . . . . . . 91 Appendix A: SEALANT REMOVAL PROCEDURE FOR EXTERIOR PRESSURIZED FUSELAGE SKIN . 97 Appendix B: REPORTING TEMPLATE - AIRPLANES WITH SCRIBE LINES. . . . . . . . . . . . . . 105 Appendix C: AIRPLANE FUSELAGE SCRIBE LINE MARK SUMMARY TABLES. . . . . . . . . . . . 107 Appendix D: SCRIBE LINE SAMPLE. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 26, 2013 A3539 4 of 110 **BOEING SERVICE BULLETIN A3539 ALERT**  **ALERT**

### Commercial **Airplanes** 

# 707 Service Bulletin **ALERT Summary**  **Number: A3539** Original Issue: April 26, 2013 ATA System: 5330 **SUBJECT:** FUSELAGE - Fuselage Skin - Inspection of the Fuselage Skin for 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 to inspect for scribe lines in the fuselage skin. Fatigue cracks can develop at scribe line locations. If this service bulletin is not done, any crack that remains undetected could grow large and cause a rapid decompression of the airplane. Although Boeing has not received reports of scribe line related cracks on 707 series airplanes, Boeing has received reports of scribe line related cracks on two 727 airplanes. One report was on a 727-100 airplane with 44,171 cycles. The crack was near a repair and caused rapid decompression of the airplane. Another report was on a 727-100 airplane with 51,195 cycles. The crack was at station 1090-1110, stringer 4L lap joint. This also resulted in rapid decompression of the airplane. A scribe line is a narrow, shallow, distinct line of damage (typically up to 0.006 inch deep), usually associated with the removal of a fillet or gap seal (skin lap joints and skin butt joints, respectively). A more detailed definition of a scribe line is included in Accomplishment Instructions Paragraph 3.B. - Identification of a "Typical" Scribe Line. A review of fleet activity yields two separate scenarios that are suspected to have caused scribe lines to the fuselage skin. The first scenario involves the paint stripping and repainting of airplanes. In the process of stripping and preparing the airplane for paint, tools were used to remove sealant and paint buildup at lap joints, at certain external approved repair doublers or door scuff plates, or around external features. Tools like scrapers (steel, wood, hard plastic, etc.), knives, or utility knives can damage the skin. Fatigue cracks can develop at scribe line locations. The second scenario is decal application on/or removal from the fuselage. To install the decals across lap joint steps or repairs, investigation into maintenance practices has shown that decals have been cut in place, using some form of knife, to allow the decal to lie flush to the skin at these stepped locations. This operation results in scribe lines at the decal cut location. Based on service reports, sharp tools have also been used for close trimming of decal outlines. This type of decal trimming also has left scribe lines on the fuselage skin.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 26, 2013 A3539 5 of 110Each of the above maintenance operations can lead to the same type of scribe line damage and subsequent premature fatigue cracks. Boeing Service Related Problem (SRP) 707-SRP-53-0247 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 and Paragraph 1.F., Approval Yes AD Related Paragraph 1.H., Weight and Balance Changes No Weight and Balance Change Paragraph 1.I., Electrical Load Data No Electrical Load Changed Paragraph 1.K., Publications Affected Yes 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 Yes Operator Supplied Parts/Material Paragraph 2.F., Special Tooling Necessary to do this Service Bulletin Yes Special Tooling Required

**ACTION Group 1-4:**  Prepare surface for inspection by removing paint and sealant at the applicable locations. Do a detailed inspection of the fuselage skin at skin lap joints, external approved repairs, and external features for any scribe line. If no scribe lines are found, no further inspections are required. If any scribe line is found, measure the depth of the scribe line. For scribe lines less than 0.001 inch deep, no repair or further inspections are required. For scribe lines greater than or equal to 0.001 inch deep, Non-Destructive Testing (NDT) inspections are required to check for cracks. If any crack is found, contact Boeing for repair instructions and do the repair. As an alternative to immediate repair, for a scribe line that qualifies, the provided Limited Return To Service (LRTS) program may be used to allow airplanes to return to revenue flight for a limited period before scribe lines are repaired. This service bulletin contains a LRTS program. **NOTE:** Further Boeing approval is not required to begin a LRTS program. The LRTS program consists of repeat inspections to detect any crack where scribe lines were found. Total airplane flight cycles, location, and the extent of the scribe line must meet specific criteria in order for a scribe line to qualify for a LRTS program. Inspections at each affected structural location within a LRTS program will be terminated with a repair. Since a scribe line can occur at any time during the service life of an airplane and at many locations, this program uses both total flight cycles and structural criticality of location to determine the inspection requirements.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 26, 2013 A3539 6 of 110 **BOEING SERVICE BULLETIN A3539 ALERT**  **ALERT**Criticality of location allows this service bulletin to address the most critical areas first and determines the inspection thresholds for each location. This service bulletin uses figures and compliance times to address all of the critical locations and their corresponding inspection thresholds. Each critical piece of structure susceptible to a scribe line is assigned to a figure. The affected structure for each group of airplanes is identified in individual figures in this service bulletin. **Group 5:** Prepare surface for inspection by removing paint and sealant at the applicable locations. Do a detailed inspection of the fuselage skin at all skin lap joints, external approved repairs, external features, skin butt joints, and decals for any scribe line. If no scribe lines are found, no further inspections are required. If any scribe line is found, measure the depth of the scribe line. For scribe lines less than 0.001 inch deep, no repair or further inspections are required. For scribe lines greater than or equal to 0.001 inch deep, contact Boeing for repair instructions and do the repair. **NOTE:**There is no LRTS program for Group 5 airplanes. **EFFECTIVITY** 707-100, 707-100B, 707-200, 707-300, 707-300B, 707-300C, 707-400, 720, 720B 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 not available for the inspections or repair procedures given in this service bulletin. **MANPOWER** Refer to Paragraph 1.G., Manpower. **MATERIAL INFORMATION** Operator Supplied Parts/Materials. Refer to Paragraph 2.A., Material - Price and Availability.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 26, 2013 A3539 7 of 110 **BOEING SERVICE BULLETIN A3539 ALERT**  **ALERT**Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 26, 2013 A3539 8 of 110 **BOEING SERVICE BULLETIN A3539 ALERT**  **ALERT**

### Commercial **Airplanes** 

# 707 Service Bulletin **ALERT Number: A3539**  Original Issue: April 26, 2013 ATA System: 5330 **SUBJECT:** FUSELAGE - Fuselage Skin - Inspection of the Fuselage Skin for 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 Document D6-1647 Part 3 for Airplane Variable Number, Line Number, and Serial Number data. This service bulletin is for the airplanes shown below.
**DESCRIPTION CONFIGURATION**  **GROUP** 707-100B Airplanes

- 1 707-300 Airplanes

- 2 707-300B Airplanes

- 3 707-300C Airplanes

- 4 707-100, 707-200, 707-400, 720, 720B Airplanes

- 5

Airplane Models: 707-100, 707-100B, 707-200, 707-300, 707-300B, 707-300C, 707-400, 720, 720B **Group Variable Number**  5 B0001 - B0029 5 B0101 - B0125

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 26, 2013 A3539 9 of 110**Group Variable Number**  5 B0201 - B0203 5 B0301 - B0306 5 B0401 - B0402 5 B0501 - B0515 5 B2001 - B2008 5 B2091 - B2092 5 B2101 - B2116 5 B2191 - B2194 5 B2199 5 B2201 - B2227 5 B2401 - B2403 5 B2501 - B2502 5 B2551 - B2553 5 B2601 - B2608 5 00001 - 00004 1 00005 - 00006 1 00101 - 00156 5 00201 - 00205 5 00301 - 00305 5 00401 - 00415 1 00416 - 00451 1 00471 - 00475 1 00501 - 00513 5 00601 - 00602 1 00701 - 00703 2 02001 - 02020 2 02101 - 02121 2 02201 - 02207 2 02301 - 02303 2 02401 - 02418 5 04001 - 04005 5 04020 - 04022 5 04101 - 04106

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 26, 2013 A3539 10 of 110 **BOEING SERVICE BULLETIN A3539 ALERT**  **ALERT Group**  **Variable Number** 5 04201 - 04218 5 04271 - 04272 5 04301 - 04303 3 05001 - 05060 3 05101 - 05138 3 05201 - 05208 3 05301 - 05312 3 05401 3 05601 - 05605 3 05631 - 05635 3 05701 - 05703 3 05801 - 05802 3 05821 - 05827 3 05831 - 05833 3 05851 - 05854 3 05891 - 05892 3 05921 - 05923 3 05941 - 05942 3 05961 - 05970 3 06001 - 06002 3 06101 3 06401 - 06404 3 06451 3 06461 4 07001 - 07017 4 07041 - 07059 4 07071 - 07081 4 07101 - 07109 4 07181 4 07191 4 07201 - 07215 4 07251 - 07271 4 07401 - 07407

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 26, 2013 A3539 11 of 110 **BOEING SERVICE BULLETIN A3539 ALERT**  **ALERT Group**  **Variable Number** 4 07451 - 07458 4 07501 - 07504 4 07601 - 07626 4 07661 - 07662 4 07681 - 07684 4 07701 - 07702 4 07801 - 07821 4 07901 - 07907 4 08001 - 08008 4 08021 4 08051 - 08056 4 08071 - 08077 4 08101 - 08104 4 08121 - 08129 4 08141 - 08144 4 08151 - 08153 4 08171 - 08173 4 08191 - 08192 4 08201 - 08210 4 08221 - 08224 4 08241 - 08244 4 08251 4 08261 4 08271 4 08301 - 08320 4 08324 - 08330 4 08333 4 08401 - 08410 4 08451 - 08452 4 08471 - 08475 4 08501 - 08502 4 08551 - 08553 4 08581 - 08582

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 26, 2013 A3539 12 of 110 **BOEING SERVICE BULLETIN A3539 ALERT**  **ALERT Group**  **Variable Number** 4 09001 - 09006 4 09101 - 09107 4 09161 - 09167 4 09201 - 09204 4 09221 - 09223 4 09227 4 09231 - 09232 4 09251 4 09271 4 09281 4 09286 - 09290 4 09411 4 09421 4 09438 4 09441 2. Spares Affected None. **B. Concurrent Requirements** None. **C. Reason** This service bulletin gives instructions to inspect for scribe lines in the fuselage skin. Fatigue cracks can develop at scribe line locations. If this service bulletin is not done, any crack that remains undetected could grow large and cause a rapid decompression of the airplane. Although Boeing has not received reports of scribe line related cracks on 707 series airplanes, Boeing has received reports of scribe line related cracks on two 727 airplanes. One report was on a 727-100 airplane with 44,171 cycles. The crack was near a repair and caused rapid decompression of the airplane. Another report was on a 727-100 airplane with 51,195 cycles. The crack was at station 1090-1110, stringer 4L lap joint. This also resulted in rapid decompression of the airplane. A scribe line is a narrow, shallow, distinct line of damage (typically up to 0.006 inch deep), usually associated with the removal of a fillet or gap seal (skin lap joints and skin butt joints, respectively). A more detailed definition of a scribe line is included in Accomplishment Instructions Paragraph 3.B. - Identification of a "Typical" Scribe Line. A review of fleet activity yields two separate scenarios that are suspected to have caused scribe lines to the fuselage skin.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 26, 2013 A3539 13 of 110 **BOEING SERVICE BULLETIN A3539 ALERT**  **ALERT**The first scenario involves the paint stripping and repainting of airplanes. In the process of stripping and preparing the airplane for paint, tools were used to remove sealant and paint buildup at lap joints, at certain external approved repair doublers or door scuff plates, or around external features. Tools like scrapers (steel, wood, hard plastic, etc.), knives, or utility knives can damage the skin. Fatigue cracks can develop at scribe line locations. The second scenario is decal application on/or removal from the fuselage. To install the decals across lap joint steps or repairs, investigation into maintenance practices has shown that decals have been cut in place, using some form of knife, to allow the decal to lie flush to the skin at these stepped locations. This operation results in scribe lines at the decal cut location. Based on service reports, sharp tools have also been used for close trimming of decal outlines. This type of decal trimming also has left scribe lines on the fuselage skin. Each of the above maintenance operations can lead to the same type of scribe line damage and subsequent premature fatigue cracks. Boeing Service Related Problem (SRP) 707-SRP-53-0247 is related to this service bulletin. **D. Description Group 1-4:**  Prepare surface for inspection by removing paint and sealant at the applicable locations. Do a detailed inspection of the fuselage skin at skin lap joints, external approved repairs, and external features for any scribe line. If no scribe lines are found, no further inspections are required. If any scribe line is found, measure the depth of the scribe line. For scribe lines less than 0.001 inch deep, no repair or further inspections are required. For scribe lines greater than or equal to 0.001 inch deep, Non-Destructive Testing (NDT) inspections are required to check for cracks. If any crack is found, contact Boeing for repair instructions and do the repair. As an alternative to immediate repair, for a scribe line that qualifies, the provided Limited Return To Service (LRTS) program may be used to allow airplanes to return to revenue flight for a limited period before scribe lines are repaired. This service bulletin contains a LRTS program. **NOTE:** Further Boeing approval is not required to begin a LRTS program. The LRTS program consists of repeat inspections to detect any crack where scribe lines were found. Total airplane flight cycles, location, and the extent of the scribe line must meet specific criteria in order for a scribe line to qualify for a LRTS program. Inspections at each affected structural location within a LRTS program will be terminated with a repair. Since a scribe line can occur at any time during the service life of an airplane and at many locations, this program uses both total flight cycles and structural criticality of location to determine the inspection requirements. Criticality of location allows this service bulletin to address the most critical areas first and determines the inspection thresholds for each location. This service bulletin uses figures and compliance times to address all of the critical locations and their corresponding inspection thresholds. Each critical piece of structure susceptible to a scribe line is assigned to a figure. The affected structure for each group of airplanes is identified in individual figures in this service bulletin.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 26, 2013 A3539 14 of 110 **BOEING SERVICE BULLETIN A3539 ALERT**  **ALERT Group 5:**  Prepare surface for inspection by removing paint and sealant at the applicable locations. Do a detailed inspection of the fuselage skin at all skin lap joints, external approved repairs, external features, skin butt joints, and decals for any scribe line. If no scribe lines are found, no further inspections are required. If any scribe line is found, measure the depth of the scribe line. For scribe lines less than 0.001 inch deep, no repair or further inspections are required. For scribe lines greater than or equal to 0.001 inch deep, contact Boeing for repair instructions and do the repair. **NOTE:**There is no LRTS program for Group 5 airplanes. The work in this service bulletin is done in the maintenance zone(s) given below. **Group 1:**
**Affected Maintenance Zones Zone**  **Model** 1-11, 1-12, 1-13, 1-14, 1-15, 1-16, 2-26 707-100B **Group 2:**
**Affected Maintenance Zones Zone**  **Model** 1-11, 1-12, 1-13, 1-14, 1-15, 1-16, 2-26 707-300 **Group 3:**
**Affected Maintenance Zones Zone**  **Model** 1-11, 1-12, 1-13, 1-14, 1-15, 1-16, 2-26 707-300B **Group 4:**
**Affected Maintenance Zones Zone**  **Model** 1-11, 1-12, 1-13, 1-14, 1-15, 1-16, 2-26 707-300C **Group 5:**
**Affected Maintenance Zones Zone**  **Model** 1-11, 1-12, 1-13, 1-14, 1-15, 1-16, 2-26 707-100, 707-200, 707-400, 720, 720B

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 26, 2013 A3539 15 of 110 **BOEING SERVICE BULLETIN A3539 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. Inspection Exemptions: Certain inspections are not required under these conditions: – Skin Lap Joints: Inspections are not required in skin lap joint areas where an existing external approved repair covers a potential scribe line, provided the repair spans a minimum of three fastener rows above and three fastener rows below the potential scribe line location. External repairs that do not meet this requirement must be removed to allow skin lap joint inspection. – If operator's records show that the airplane has never been stripped or repainted since delivery from Boeing, then the skin lap joint and external approved repair scribe line inspections are not required, except as noted below: – If a decal is installed, or was previously installed, across an area that requires inspection, the inspection exemption does not apply. The skin lap joint and external approved repair inspection must still be done for the affected area at the compliance time in accordance with this service bulletin.
**Group 1-4:** The inspection compliance time is based upon analysis of fuselage geometry and loads. Group 1-4 airplanes have three (3) areas for scribe line inspections. The areas are as follows: — Skin Lap Joints — External Approved Repairs — External Features Boeing recommends that operators do inspections for scribe lines at the times given in the Compliance tables. The Compliance tables are broken down as follows: 1. Table 1 shows the initial scribe line inspection for the three (3) areas to be inspected. 2. Tables 2 through 7 show the Limited Return To Service (LRTS) repeat inspection intervals for the three (3) areas to be inspected. LRTS inspections are not an option for airplanes with more than 20,000 total flight cycles. 3. Table 8 shows how to disposition known existing scribe line damage outside of the service bulletin inspection areas. **Group 5:** Group 5 airplanes have five (5) areas for scribe line inspections. The areas are as follows: — Skin Lap Joints — External Approved Repairs — External Features — Skin Butt Joints — Decals

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 26, 2013 A3539 16 of 110 **BOEING SERVICE BULLETIN A3539 ALERT**  **ALERT**Boeing recommends that operators do inspections for scribe lines at the times given in the Compliance table. The Compliance table is broken down as follows: 1. Table 9 shows the initial scribe line inspection for the five (5) areas to be inspected. **NOTE:**There is no LRTS program for Group 5 airplanes. **Group 1-4: Table 1 : Scribe Line Inspection on Fuselage Skin at Skin Lap Joints, External Approved Repairs, and**  **External Features - Initial Inspection Repeat Interval**  **(Not to Exceed) Compliance Time**  **Action Condition** 

- Within 12 months after the origi- nal issue date of this service bulletin. Do surface preparations forscribe line inspections in accordance with Accomplishment Instructions Paragraph 3.B.3 - Part 1. Airplanes with more than 15,000 total flight cycles as of the original issuedate of this service bulletin. And Do detailed inspections of theapplicable skin lap joints, external approved repairs, and external features for any scribe line using the tables in accordancewith Accomplishment Instructions Paragraph 3.B.4 - Part 2.

- Before 15,000 total flight cycles or within 24 months after theoriginal issue date of this service bulletin, whichever occurs later. Do surface preparations forscribe line inspections in accordance with Accomplishment Instructions Paragraph 3.B.3 - Part 1. Airplanes with 15,000 total flight cycles or less as of the original issuedate of this service bulletin. And Do detailed inspections of theapplicable skin lap joints, external approved repairs, and external features for any scribe line using the tables in accordancewith Accomplishment Instructions Paragraph 3.B.4 - Part 2.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 26, 2013 A3539 17 of 110 **BOEING SERVICE BULLETIN A3539 ALERT**  **ALERT Group 1-4:**  **Table 1 : Scribe Line Inspection on Fuselage Skin at Skin Lap Joints, External Approved Repairs, and External Features - Initial Inspection**  **Repeat Interval (Not to Exceed)**  **Compliance Time Action**  **Condition**

- Before further flight. No further inspections are re-quired in accordance with Accomplishment Instructions Paragraph 3.B.5 - Part 3. No scribe line is found.

And Do surface finish restoration inaccordance with Accomplishment Instructions Paragraph 3.B.9 - Part 7.

- Before further flight. Measure the scribe line depthin accordance with Accomplishment Instructions Paragraph 3.B.6 - Part 4. Any scribe line is found.

- Before further flight. No repair or further inspections are required in accordance with Accomplishment Instructions Paragraph 3.B.6 - Part 4. Scribe line is found less than 0.001 inch deep.

And Do surface finish restoration inaccordance with Accomplishment Instructions Paragraph 3.B.9 - Part 7.

- Before further flight. Do the applicable Non-Destruc- tive Testing (NDT) inspection for any crack in accordance with Accomplishment Instructions Paragraph 3.B.7 - Part 5. Scribe line is greater than or equal to 0.001 inch deep

And Do surface finish restoration inaccordance with Accomplishment Instructions Paragraph 3.B.9 - Part 7.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 26, 2013 A3539 18 of 110 **BOEING SERVICE BULLETIN A3539 ALERT**  **ALERT Group 1-4:**  **Table 1 : Scribe Line Inspection on Fuselage Skin at Skin Lap Joints, External Approved Repairs, and External Features - Initial Inspection**  **Repeat Interval (Not to Exceed)**  **Compliance Time Action**  **Condition**
Refer to the LRTS Tables 2 to 7 for repeat intervals. Before LRTS repeat intervals in Tables 2 to 7. Do the LRTS repeat inspectionprogram in accordance with Accomplishment Instructions Paragraph 3.B.8 - Part 6. If no crack is found and the scribe line is greater than or equal to 0.001 inch deep and less than or equal to 0.006 inch deep. And

- Before further flight. Do surface finish restoration inaccordance with Accomplishment Instructions Paragraph 3.B.9 - Part 7. Or

- Before further flight. Document and propose a repair to Boeing in accordance with Accomplishment Instructions Paragraph 3.B.7 - Part 5. Do the repair. And Do surface finish restoration inaccordance with Accomplishment Instructions Paragraph 3.B.9 - Part 7.

- Before further flight. Document and propose a repair to Boeing in accordance with Accomplishment Instructions Paragraph 3.B.7 - Part 5. Do the repair. If no crack is found and the scribe line is greater than 0.006 inch deep.

And Do surface finish restoration inaccordance with Accomplishment Instructions Paragraph 3.B.9 - Part 7.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 26, 2013 A3539 19 of 110 **BOEING SERVICE BULLETIN A3539 ALERT**  **ALERT Group 1-4:**  **Table 1 : Scribe Line Inspection on Fuselage Skin at Skin Lap Joints, External Approved Repairs, and External Features - Initial Inspection**  **Repeat Interval (Not to Exceed)**  **Compliance Time Action**  **Condition**

- Before further flight. Document and propose a repair to Boeing in accordance with Accomplishment Instructions Paragraph 3.B.7 - Part 5. Do the repair. If any crack is found.

And Do surface finish restoration inaccordance with Accomplishment Instructions Paragraph 3.B.9 - Part 7.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 26, 2013 A3539 20 of 110 **BOEING SERVICE BULLETIN A3539 ALERT**  **ALERT Group 1:**  **Table 2 - Scribe Line Inspections on Fuselage Skin at Skin Lap Joints - Limited Return To Service Repeat Inspection Intervals**  **Repeat Interval (Not to Exceed)**  **Compliance Time Action**  **Condition** Do Part 1 - Surface Preparation, Part 2 -Detailed Inspection, and the applicable NonDestructive Testing (NDT) inspection in accordance with Accomplishment Instructions Paragraph 3.B.8 - Part 6 for the skin lap joint areas that follow: Airplanes with scribelines using a Limited Return To Service (LRTS) Program Skin Lap Joints LRTS inspections are not an option for airplanes with more than 20,000 total flight cycles. Flight Cycles Station Location From - To Stringer Location 1,100

- STA NLG - 481 S-30R 800

- STA 960 - 1124.10 S-29R 1,400

- STA 1124.10 - 1265.20 1,700

- STA 312 - 360 S-25R 2,100

- STA 360 - 481 2,200

- STA 1364.10- 1440 S-24R 1,400

- STA 259.50 - 360 S-20R 1,400

- STA 360 - Door Cutout 1,400

- STA 580 - 600K 1,200

- STA 960 - Door Cutout 1,200

- Door Cutout - STA 1164.10 2,900

- STA 1164.10 - Door Cutout 2,900

- Door Cutout - STA 1265.20 2,000

- STA 360 - Door Cutout S-14R 2,000

- Door Cutout - STA 481 3,000

- STA 1124.10 - 1164.10 2,000

- STA 1241 - Door Cutout 2,400

- Door Cutout - STA 1364.10 1,800

- STA 1241 - 1384.10 S-10R 1,900

- STA 441 - 580 S-6R 3,000

- STA 441 - 481 S-6L 2,000

- STA 360 - 481 S-14L 2,000

- STA 1220 - Door Cutout 1,400

- STA 259.50 - 360 S-20L

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 26, 2013 A3539 21 of 110 **BOEING SERVICE BULLETIN A3539 ALERT**  **ALERT Group 1:**  **Table 2 - Scribe Line Inspections on Fuselage Skin at Skin Lap Joints - Limited Return To Service Repeat Inspection Intervals**  **Repeat Interval (Not to Exceed)**  **Compliance Time Action**  **Condition**
STA 360 - 600 1,400

- 1,300

- STA 960 - 1164.10 2,900

- STA 1164.10 - 1265.20 1,700

- STA 312 - 360 S-25L 2,000

- STA 441 - 481 800

- STA 960 - 1124.10 S-29L 1,400

- STA 1124.10- 1265.20

- Before further flight. Document and propose a repair to Boeingin accordance with Accomplishment Instructions Paragraph 3.B.8 - Part 6. Do the repair. If no crack is found.

And

- Before further flight. Do surface finish restoration in accordance with Accomplishment Instructions Paragraph 3.B.9 - Part 7. Or Repeat at intervals definedabove in this table. - Repeat the LRTS program in accordance with this service bulletin.

And

- Before further flight. Do surface finish restoration in accordance with Accomplishment Instructions Paragraph 3.B.9 - Part 7.

- Before further flight. Document and propose a repair to Boeingin accordance with Accomplishment Instructions Paragraph 3.B.8 - Part 6. Do the repair. If any crack is found.

And

- Before further flight. Do surface finish restoration in accordance with Accomplishment Instructions Paragraph 3.B.9 - Part 7.

- Before 20,000 to- tal flight cycles. Contact Boeing for additional inspections or repair in accordance with Accomplishment Instructions Paragraph 3.B.8 - Part 6. Do the additional inspections or repair. Airplanes with scribelines using a LRTS Program Inspection.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 26, 2013 A3539 22 of 110 **BOEING SERVICE BULLETIN A3539 ALERT**  **ALERT Group 2:**  **Table 3 - Scribe Line Inspections on Fuselage Skin at Skin Lap Joints - Limited Return To Service Repeat Inspection Intervals**  **Repeat Interval (Not to Exceed)**  **Compliance Time Action**  **Condition** Do Part 1 - Surface Preparation, Part 2 -Detailed Inspection, and the applicable NonDestructive Testing (NDT) inspection in accordance with Accomplishment Instructions Paragraph 3.B.8 - Part 6 for the skin lap joint areas that follow: Airplanes with scribelines using a Limited Return To Service (LRTS) Program Skin Lap Joints LRTS inspections are not an option for airplanes with more than 20,000 total flight cycles. Flight Cycles Station Location From - To Stringer Location 1,100

- STA NLG - 481 S-30R 800

- STA 960 - 1124.10 S-29R 1,400

- STA 1124.10 - 1265.20 1,700

- STA 312 - 360 S-25R 2,100

- STA 360 - 481 2,200

- STA 1364.10 - 1440 S-24R 1,400

- STA 259.50 - 360 S-20R 1,400

- STA 360 - Door Cutout 1,400

- STA 580 - 600K 1,200

- STA 960 - Door Cutout 1,200

- Door Cutout - STA 1164.10 2,900

- STA 1164.10 - Door Cutout 2,900

- Door Cutout - STA 1265.20 2,000

- STA 360 - Door Cutout S-14R 2,000

- Door Cutout - STA 481 3,000

- STA 1124.10 - 1164.10 2,000

- STA 1241 - Door Cutout 2,400

- Door Cutout - STA 1364.10 1,800

- STA 1241 - 1384.10 S-10R 1,900

- STA 441 - 580 S-6R 3,000

- STA 441 - 481 S-6L 2,000

- STA 360 - 481 S-14L 2,000

- STA 1220 - Door Cutout 1,400

- STA 259.50 - 360 S-20L

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 26, 2013 A3539 23 of 110 **BOEING SERVICE BULLETIN A3539 ALERT**  **ALERT Group 2:**  **Table 3 - Scribe Line Inspections on Fuselage Skin at Skin Lap Joints - Limited Return To Service Repeat Inspection Intervals**  **Repeat Interval (Not to Exceed)**  **Compliance Time Action**  **Condition**
STA 360 - 441 1,400

- 2,000

- STA 441 - 600H 1,300

- STA 960 - 1164.10 2,900

- STA 1164.10 - 1265.20 1,700

- STA 312 - 360 S-25L 2,000

- STA 441 - 481 800

- STA 960 - 1124.10 S-29L 1,400

- STA 1124.10- 1265.20

- Before further flight. Document and propose a repair to Boeingin accordance with Accomplishment Instructions Paragraph 3.B.8 - Part 6. Do the repair. If no crack is found.

And

- Before further flight. Do surface finish restoration in accordance with Accomplishment Instructions Paragraph 3.B.9 - Part 7. Or Repeat at intervals definedabove in this table. - Repeat the LRTS program in accordance with this service bulletin.

And

- Before further flight. Do surface finish restoration in accordance with Accomplishment Instructions Paragraph 3.B.9 - Part 7.

- Before further flight. Document and propose a repair to Boeingin accordance with Accomplishment Instructions Paragraph 3.B.8 - Part 6. Do the repair. If any crack is found.

And

- Before further flight. Do surface finish restoration in accordance with Accomplishment Instructions Paragraph 3.B.9 - Part 7.

- Before 20,000 to- tal flight cycles. Contact Boeing for additional inspections or repair in accordance with Accomplishment Instructions Paragraph 3.B.8 - Part 6. Do the additional inspections or repair. Airplanes with scribelines using a LRTS Program Inspection.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 26, 2013 A3539 24 of 110 **BOEING SERVICE BULLETIN A3539 ALERT**  **ALERT Group 3:**  **Table 4 - Scribe Line Inspections on Fuselage Skin at Skin Lap Joints - Limited Return To Service Repeat Inspection Intervals**  **Repeat Interval (Not to Exceed)**  **Compliance Time Action**  **Condition** Do Part 1 - Surface Preparation, Part 2 -Detailed Inspection, and the applicable NonDestructive Testing (NDT) inspection in accordance with Accomplishment Instructions Paragraph 3.B.8 - Part 6 for the skin lap joint areas that follow: Airplanes with scribelines using a Limited Return To Service (LRTS) Program Skin Lap Joints LRTS inspections are not an option for airplanes with more than 20,000 total flight cycles. Flight Cycles Station Location From - To Stringer Location 1,100

- STA NLG - 481 S-30R 800

- STA 960 - 1124.10 S-29R 1,400

- STA 1124.10 - 1265.20 1,700

- STA 312 - 360 S-25R 2,100

- STA 360 - 481 2,200

- STA 1364.10 - 1440 S-24R 1,400

- STA 259.50 - 360 S-20R 1,400

- STA 360 - Door Cutout 1,400

- STA 580 - 600K 1,200

- STA 960 - Door Cutout 1,200

- Door Cutout - STA 1164.10 2,900

- STA 1164.10 - Door Cutout 2,900

- Door Cutout - STA 1265.20 2,000

- STA 360 - Door Cutout S-14R 2,000

- Door Cutout - STA 481 3,000

- STA 1124.10 - 1164.10 2,000

- STA 1241 - Door Cutout 2,400

- Door Cutout - STA 1364.10 1,800

- STA 1241 - 1384.10 S-10R 1,900

- STA 441 - 580 S-6R 3,000

- STA 441 - 481 S-6L 2,000

- STA 360 - 481 S-14L 2,000

- STA 1220 - Door Cutout 1,400

- STA 259.50 - 360 S-20L

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 26, 2013 A3539 25 of 110 **BOEING SERVICE BULLETIN A3539 ALERT**  **ALERT Group 3:**  **Table 4 - Scribe Line Inspections on Fuselage Skin at Skin Lap Joints - Limited Return To Service Repeat Inspection Intervals**  **Repeat Interval (Not to Exceed)**  **Compliance Time Action**  **Condition**
STA 360 - 441 1,400

- 2,000

- STA 441 - 600H 1,300

- STA 960 - 1164.10 2,900

- STA 1164.10 - 1265.20 1,700

- STA 312 - 360 S-25L 2,000

- STA 441 - 481 800

- STA 960 - 1124.10 S-29L 1,400

- STA 1124.10 - 1265.20

- Before further flight. Document and propose a repair to Boeingin accordance with Accomplishment Instructions Paragraph 3.B.8 - Part 6. Do the repair. If no crack is found.

And

- Before further flight. Do surface finish restoration in accordance with Accomplishment Instructions Paragraph 3.B.9 - Part 7. Or Repeat at intervals definedabove in this table. - Repeat the LRTS program in accordance with this service bulletin.

And

- Before further flight. Do surface finish restoration in accordance with Accomplishment Instructions Paragraph 3.B.9 - Part 7.

- Before further flight. Document and propose a repair to Boeingin accordance with Accomplishment Instructions Paragraph 3.B.8 - Part 6. Do the repair. If any crack is found.

And

- Before further flight. Do surface finish restoration in accordance with Accomplishment Instructions Paragraph 3.B.9 - Part 7.

- Before 20,000 to- tal flight cycles. Contact Boeing for additional inspections or repair in accordance with Accomplishment Instructions Paragraph 3.B.8 - Part 6. Do the additional inspections or repair. Airplanes with scribelines using a LRTS Program Inspection.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 26, 2013 A3539 26 of 110 **BOEING SERVICE BULLETIN A3539 ALERT**  **ALERT Group 4:**  **Table 5 - Scribe Line Inspections on Fuselage Skin at Skin Lap Joints - Limited Return To Service Repeat Inspection Intervals**  **Repeat Interval (Not to Exceed)**  **Compliance Time Action**  **Condition** Do Part 1 - Surface Preparation, Part 2 -Detailed Inspection, and the applicable NonDestructive Testing (NDT) inspection in accordance with Accomplishment Instructions Paragraph 3.B.8 - Part 6 for the skin lap joint areas that follow: Airplanes with scribelines using a Limited Return To Service (LRTS) Program Skin Lap Joints LRTS inspections are not an option for airplanes with more than 20,000 total flight cycles. Flight Cycles Station Location From - To Stringer Location 1,100

- STA NLG - 481 S-30R 800

- STA 960 - 1124.10 S-29R 1,400

- STA 1124.10 - 1265.20 1,700

- STA 312 - 360 S-25R 2,100

- STA 360 - 481 2,200

- STA 1364.10 - 1440 S-24R 1,400

- STA 259.50 - 360 S-20R 1,400

- STA 360 - Door Cutout 1,400

- STA 580 - 600K 1,200

- STA 960 - Door Cutout 1,200

- Door Cutout - STA 1164.10 2,900

- STA 1164.10 - Door Cutout 2,900

- Door Cutout - STA 1265.20 2,000

- STA 360 - Door Cutout S-14R 2,000

- Door Cutout - STA 481 3,000

- STA 1124.10 - 1164.10 2,000

- STA 1241 - Door Cutout 2,400

- Door Cutout - STA 1364.10 1,800

- STA 1241 - 1384.10 S-10R 1,900

- STA 441 - 580 S-6R 3,000

- STA 441 - Door Cutout S-6L 2,000

- STA 360 - Door Cutout S-14L 2,000

- STA 1220 - Door Cutout 1,400

- STA 259.50 - 360 S-20L

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 26, 2013 A3539 27 of 110 **BOEING SERVICE BULLETIN A3539 ALERT**  **ALERT Group 4:**  **Table 5 - Scribe Line Inspections on Fuselage Skin at Skin Lap Joints - Limited Return To Service Repeat Inspection Intervals**  **Repeat Interval (Not to Exceed)**  **Compliance Time Action**  **Condition**
STA 360 - 441 1,400

- 2,000

- STA 600E - 600H 1,300

- STA 960 - 1164.10 2,900

- STA 1164.10 - 1265.20 1,700

- STA 312 - 360 S-25L 2,000

- STA 441 - 481 800

- STA 960 - 1144.10 S-29L 1,400

- STA 1144.10 - 1265.20

- Before further flight. Document and propose a repair to Boeingin accordance with Accomplishment Instructions Paragraph 3.B.8 - Part 6. Do the repair. If no crack is found.

And

- Before further flight. Do surface finish restoration in accordance with Accomplishment Instructions Paragraph 3.B.9 - Part 7. Or Repeat at intervals definedabove in this table. - Repeat the LRTS program in accordance with this service bulletin.

And

- Before further flight. Do surface finish restoration in accordance with Accomplishment Instructions Paragraph 3.B.9 - Part 7.

- Before further flight. Document and propose a repair to Boeingin accordance with Accomplishment Instructions Paragraph 3.B.8 - Part 6. Do the repair. If any crack is found.

And

- Before further flight. Do surface finish restoration in accordance with Accomplishment Instructions Paragraph 3.B.9 - Part 7.

- Before 20,000 to- tal flight cycles. Contact Boeing for additional inspections or repair in accordance with Accomplishment Instructions Paragraph 3.B.8 - Part 6. Do the additional inspections or repair. Airplanes with scribelines using a LRTS Program Inspection.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 26, 2013 A3539 28 of 110 **BOEING SERVICE BULLETIN A3539 ALERT**  **ALERT Group 1-4:**  **Table 6 - Scribe Line Inspections on Fuselage Skin at External Approved Repairs - Limited Return To Service Repeat Inspection Intervals**  **Repeat Interval (Not to Exceed)**  **Compliance Time Action**  **Condition** Do Part 1 - Surface Preparation, Part 2 - Detailed Inspection, and the applicable NonDestructive Testing (NDT) inspection in accordance with Accomplishment InstructionsParagraph 3.B.8 - Part 6 for the External Approved Repair areas that follow: Airplanes with scribelines using a Limited Return To Service (LRTS) ProgramExternal Approved Repairs LRTS inspections are not an option for airplanes with more than 20,000 total flight cycles. Flight Cycles Stringer Location From - To Station Location From - To

1,200

- S30R - S30L STA 259.50 - STA 1440External Approved Repairs - 20 inches or longer on any side. 1,500

- S30R - S30L STA 259.50 - STA 1440External Approved Repairs - Less than 20 inches on any side.

- Before further flight. Document and propose a repair to Boeing in accordance with Accomplishment Instructions Paragraph 3.B.8 - Part 6. Do the repair. If no crack is found.

And

- Before further flight. Do surface finish restoration in accordance with Accomplishment Instructions Paragraph 3.B.9 - Part 7. Or Repeat at intervals definedabove in this table. - Repeat the LRTS program in accordance with this service bulletin.

And

- Before further flight. Do surface finish restoration in accordance with Accomplishment Instructions Paragraph 3.B.9 - Part 7.

- Before further flight. Document and propose a repair to Boeing in accordance with Accomplishment Instructions Paragraph 3.B.8 - Part 6. Do the repair. If any crack is found.

And

- Before further flight. Do surface finish restoration in accordance with Accomplishment Instructions Paragraph 3.B.9 - Part 7.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 26, 2013 A3539 29 of 110 **BOEING SERVICE BULLETIN A3539 ALERT**  **ALERT Group 1-4:**  **Table 6 - Scribe Line Inspections on Fuselage Skin at External Approved Repairs - Limited Return To Service Repeat Inspection Intervals**  **Repeat Interval (Not to Exceed)**  **Compliance Time Action**  **Condition**

- Before 20,000 to- tal flight cycles. Contact Boeing for additional inspections or repair in accordance with Accomplishment Instructions Paragraph 3.B.8 - Part 6. Do the additional inspections or repair. Airplanes with scribelines using a LRTS Program Inspection.

**Group 1-4: Table 7 - Scribe Line Inspections on Fuselage Skin at External Features - Limited Return To Service**  **Repeat Inspection Intervals Repeat Interval**  **(Not to Exceed) Compliance**  **Time Action**  **Condition** Do Part 1 - Surface Preparation, Part 2 - Detailed Inspection, and the applicable Non-Destructive Testing (NDT) inspection in accordance with Accomplishment Instructions Paragraph 3.B.8 - Part 6 for the External Feature areas that follow: Airplanes with scribe lines using a Limited Return To Service (LRTS) Program External Features LRTS inspections arenot an option for airplanes with more than20,000 total flight cycles. Flight Cycles External Feature Station Loca- tion Stringer Location 2,500

- Air Traffic Control/ L- Band Antenna STA 294.50 to 312.00S-25L To S25R 1,750

- Antenna - LowRange Radio Altimeter STA 1010 S-30L To S- 30R
1,750

- Antenna - LowRange Radio Altimeter STA 1029 S-30L To S- 30R
1,750

- Antenna - LowRange Radio Altimeter STA 1050 S-30L To S- 30R
1,750

- Antenna - LowRange Radio Altimeter STA 1069 S-30L To S- 30R

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 26, 2013 A3539 30 of 110 **BOEING SERVICE BULLETIN A3539 ALERT**  **ALERT Group 1-4:**  **Table 7 - Scribe Line Inspections on Fuselage Skin at External Features - Limited Return To Service Repeat Inspection Intervals**  **Repeat Interval (Not to Exceed)**  **Compliance Time**  **Action Condition** 

- Before further flight.Document and propose a repair to Boeing in accordance with Accomplishment Instructions Paragraph 3.B.8 - Part 6. Do the repair. If no crack is found.

And

- Before further flight.Do surface finish restoration in accordance with Accomplishment Instructions Paragraph 3.B.9 - Part 7. Or Repeat at intervals definedabove in this table. - Repeat the LRTS program in accordance with this service bulletin.

And

- Before further flight.Do surface finish restoration in accordance with Accomplishment Instructions Paragraph 3.B.9 - Part 7.

- Before further flight.Document and propose a repair to Boeing in accordance with Accomplishment Instructions Paragraph 3.B.8 - Part 6. Do the repair. If any crack is found.

And

- Before further flight.Do surface finish restoration in accordance with Accomplishment Instructions Paragraph 3.B.9 - Part 7.

- Before 20,000 total flight cycles. Contact Boeing for additional inspections or repair inaccordance with Accomplishment Instructions Paragraph 3.B.8 - Part 6. Do the additional inspections or repair. Airplanes with scribe lines using a LRTS Program Inspection.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 26, 2013 A3539 31 of 110 **BOEING SERVICE BULLETIN A3539 ALERT**  **ALERT Group 1-4:**  **Table 8: Known Existing Scribe Line Damage - Inspection for Scribe Lines Outside of Service Bulletin Inspection Areas**  **Repeat Interval (Not to Exceed)**  **Compliance Time Action**  **Condition**

- Before 20,000 total flight cycles. Do surface preparations in ac- cordance with Accomplishment Instructions Paragraph 3.B.3 - Part 1. Airplanes with knownexisting scribe line damage outside of this Service Bulletin Inspection areas. And Measure the scribe line depthin accordance with Accomplishment Instructions Paragraph 3.B.10 - Part 8 for the fuselage areas that follow: Skin Lap Joints External Approved Repairs External Features (Antennas, Lights, Beacons) Skin Butt Joints Decals and Fairings

- Before further flight. No repair or further inspections are required in accordance with Accomplishment Instructions Paragraph 3.B.10 - Part 8. Scribe line is found less than 0.001 inch deep.

And Do surface finish restoration inaccordance with Accomplishment Instructions Paragraph 3.B.9 - Part 7.

- Before further flight. Do the applicable Non-Destruc- tive Testing (NDT) inspection for any crack in accordance with Accomplishment Instructions Paragraph 3.B.10 - Part 8. Scribe line is greater than or equal to 0.001 inch deep

And Do surface finish restoration inaccordance with Accomplishment Instructions Paragraph 3.B.9 - Part 7.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 26, 2013 A3539 32 of 110 **BOEING SERVICE BULLETIN A3539 ALERT**  **ALERT Group 1-4:**  **Table 8: Known Existing Scribe Line Damage - Inspection for Scribe Lines Outside of Service Bulletin Inspection Areas**  **Repeat Interval (Not to Exceed)**  **Compliance Time Action**  **Condition**

- Before further flight. No repair or further inspections are required in accordance with Accomplishment Instructions Paragraph 3.B.10 - Part 8. If no crack is found and the scribe line is greater than or equal to 0.001 inch deep and less than or equal to 0.004 inch deep. And

- Before further flight. Do surface finish restoration inaccordance with Accomplishment Instructions Paragraph 3.B.9 - Part 7.

- Before 20,000 total flight cycles. Contact Boeing for additionalinspections or repair in accordance with Accomplishment Instructions Paragraph 3.B.10 -Part 8. Do the additional inspections or repair. If no crack is found and the scribe line is greater than 0.004 inch deep and less than or equal to 0.006 inch deep.

And

- Before further flight. Do surface finish restoration inaccordance with Accomplishment Instructions Paragraph 3.B.9 - Part 7.

- Before further flight. Document and propose a repair to Boeing in accordance with Accomplishment Instructions Paragraph 3.B.10 - Part 8. Do the repair. If no crack is found and the scribe line is greater than 0.006 inch deep.

And Do surface finish restoration inaccordance with Accomplishment Instructions Paragraph 3.B.9 - Part 7.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 26, 2013 A3539 33 of 110 **BOEING SERVICE BULLETIN A3539 ALERT**  **ALERT Group 1-4:**  **Table 8: Known Existing Scribe Line Damage - Inspection for Scribe Lines Outside of Service Bulletin Inspection Areas**  **Repeat Interval (Not to Exceed)**  **Compliance Time Action**  **Condition**

- Before further flight. Document and propose a repair to Boeing in accordance with Accomplishment Instructions Paragraph 3.B.10 - Part 8. Do the repair. If any crack is found.

And Contact Boeing for additional inspections in accordance with Accomplishment Instructions Paragraph 3.B.10 - Part 8. Do the additional inspections. And Do surface finish restoration inaccordance with Accomplishment Instructions Paragraph 3.B.9 - Part 7. **Group 5: Table 9 : Scribe Line Inspection on Fuselage Skin at Skin Lap Joints, External Approved Repairs, External**  **Features, Skin Butt Joints, and Decals - Initial Inspection Repeat Interval**  **(Not to Exceed) Compliance Time**  **Action Condition** 

- Within 12 months after the origi- nal issue date of this service bulletin. Do surface preparations forscribe line inspections in accordance with Accomplishment Instructions Paragraph 3.B.3 - Part 1. Airplanes with more than 15,000 total flight cycles as of the original issuedate of this service bulletin. And Do detailed inspections of allskin lap joints, external approved repairs, external features, skin butt joints, and decals for any scribe line using thetable in accordance with Accomplishment Instructions Paragraph 3.B.4 - Part 2.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 26, 2013 A3539 34 of 110 **BOEING SERVICE BULLETIN A3539 ALERT**  **ALERT Group 5:**  **Table 9 : Scribe Line Inspection on Fuselage Skin at Skin Lap Joints, External Approved Repairs, External Features, Skin Butt Joints, and Decals - Initial Inspection**  **Repeat Interval (Not to Exceed)**  **Compliance Time Action**  **Condition**

- Within 24 months after the origi- nal issue date of this service bulletin or before 15,000 total flight cycles, whichever occurs later. Do surface preparations forscribe line inspections in accordance with Accomplishment Instructions Paragraph 3.B.3 - Part 1. Airplanes with 15,000 total flight cycles or less as of the original issuedate of this service bulletin. And Do detailed inspections of allskin lap joints, external approved repairs, external features, skin butt joints, and decals for any scribe line using thetable in accordance with Accomplishment Instructions Paragraph 3.B.4 - Part 2.

- Before further flight. No further inspections are re-quired in accordance with Accomplishment Instructions Paragraph 3.B.5 - Part 3. No scribe line is found.

And Do surface finish restoration inaccordance with Accomplishment Instructions Paragraph 3.B.9 - Part 7.

- Before further flight. Measure the scribe line depthin accordance with Accomplishment Instructions Paragraph 3.B.6 - Part 4. Any scribe line is found.

- Before further flight. No repair or further inspections are required in accordance with Accomplishment Instructions Paragraph 3.B.6 - Part 4. Scribe line is found less than 0.001 inch deep.

And Do surface finish restoration inaccordance with Accomplishment Instructions Paragraph 3.B.9 - Part 7.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 26, 2013 A3539 35 of 110 **BOEING SERVICE BULLETIN A3539 ALERT**  **ALERT Group 5:**  **Table 9 : Scribe Line Inspection on Fuselage Skin at Skin Lap Joints, External Approved Repairs, External Features, Skin Butt Joints, and Decals - Initial Inspection**  **Repeat Interval (Not to Exceed)**  **Compliance Time Action**  **Condition**

- Before further flight. Contact Boeing for repair instruc-tions and do the repair in accordance with Accomplishment Instructions Paragraph 3.B.6 - Part 4. Scribe line is greater than or equal to 0.001 inch deep

And Do surface finish restoration inaccordance with Accomplishment Instructions Paragraph 3.B.9 - Part 7. **F. Approval** 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. 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 examine the work — Time to cure the materials — Time to make the parts — Time to find the tools.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 26, 2013 A3539 36 of 110 **BOEING SERVICE BULLETIN A3539 ALERT**  **ALERT Group 1:**  **Scribe Line Inspection Elapsed Hours**  **Task Hours Number of Persons**  **Task** 20.0 80.0 4 Figure 1 6.0 12.0 2 Figure 5 2.0 4.0 2 Figure 9 28.0 * 96.0 * TOTAL FOR EACH AIRPLANE * Total Task Hours and Elapsed Hours dependent upon total number of fuselage areas being inspected. * Additional time is required for paint and sealant removal. * More time will be required for additional inspections and repairs if scribe lines or other damage is found. * More time may be required for inspections around large repair doublers. **Group 2: Scribe Line Inspection**  **Elapsed Hours Task Hours**  **Number of Persons Task**  20.0 80.0 4 Figure 2 6.0 12.0 2 Figure 6 2.0 4.0 2 Figure 9 28.0 * 96.0 * TOTAL FOR EACH AIRPLANE * Total Task Hours and Elapsed Hours dependent upon total number of fuselage areas being inspected. * Additional time is required for paint and sealant removal. * More time will be required for additional inspections and repairs if scribe lines or other damage is found. * More time may be required for inspections around large repair doublers. **Group 3: Scribe Line Inspection**  **Elapsed Hours Task Hours**  **Number of Persons Task**  20.0 80.0 4 Figure 3 6.0 12.0 2 Figure 7 2.0 4.0 2 Figure 9 28.0 * 96.0 * TOTAL FOR EACH AIRPLANE * Total Task Hours and Elapsed Hours dependent upon total number of fuselage areas being inspected.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 26, 2013 A3539 37 of 110 **BOEING SERVICE BULLETIN A3539 ALERT**  **ALERT Group 3:**  **Scribe Line Inspection Elapsed Hours**  **Task Hours Number of Persons**  **Task** * Additional time is required for paint and sealant removal. * More time will be required for additional inspections and repairs if scribe lines or other damage is found. * More time may be required for inspections around large approved repairs. **Group 4: Scribe Line Inspection**  **Elapsed Hours Task Hours**  **Number of Persons Task**  20.0 80.0 4 Figure 4 6.0 12.0 2 Figure 8 2.0 4.0 2 Figure 9 28.0 * 96.0 * TOTAL FOR EACH AIRPLANE * Total Task Hours and Elapsed Hours dependent upon total number of fuselage areas being inspected. * Additional time is required for paint and sealant removal. * More time will be required for additional inspections and repairs if scribe lines or other damage is found. * More time may be required for inspections around large approved repairs. **Group 5: Scribe Line Inspection**  **Elapsed Hours Task Hours**  **Number of Persons Task**  24.0 96.0 4 Figure 11 24.0 * 96.0 * TOTAL FOR EACH AIRPLANE * Total Task Hours and Elapsed Hours dependent upon total number of fuselage areas being inspected. * Additional time is required for paint and sealant removal. * More time will be required for additional inspections and repairs if scribe lines or other damage is found. * More time may be required for inspections around large approved repairs. **H. Weight and Balance Changes** None.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 26, 2013 A3539 38 of 110 **BOEING SERVICE BULLETIN A3539 ALERT**  **ALERT I. Electrical Load Data**  Not changed. **J. References** 1. Existing Data: a. Boeing Service Related Problem (SRP) 707-SRP-53-0247 b. Standard Overhaul Practices Manual (SOPM) 20-30-03, 20-43-03 c. 707 Non-Destructive Testing (NDT) Manual Part 10, 53-30-01; Part 4, 53-30-05; Part 4, 53-30-06; Part 6, 51-00-00, Figure 23; Part 6, 51-00-00, Figure 4; Part 6, 53-30-22; TR 06-10, Part 6, 53-30-24; TR 06-11, Part 6, 53-30-25; TR 06-12, Part 6, 53-30-26 d. 707 Aircraft Maintenance Manual (AMM) 51-2-141, 51-3-0 e. Service Bulletin Index Document D6-1647 Part 3 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 **Chapter-Section Publication**  51-2 707 Aircraft Maintenance Manual 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. **M. Software Accomplishment Summary** Not affected.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 26, 2013 A3539 39 of 110 **BOEING SERVICE BULLETIN A3539 ALERT**  **ALERT**Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 26, 2013 A3539 40 of 110 **BOEING SERVICE BULLETIN A3539 ALERT**  **ALERT**

BLANK PAGE**2. MATERIAL INFORMATION A. Material - Price and Availability**  None. **B. Industry Support Information** Boeing warranty remedies are not available for the inspections or repair procedures given in this service bulletin. **C. Parts Necessary for Each Airplane** 1. Kits/Parts: None. 2. Parts and Materials Supplied by the Operator:
**Notes Name**  **QTY Part Number /**  **Specification** (b) (c) (g) Chemical Conversion Coating 10 Ounces Type 2, Class A (a) (c) (g) Primer 24 Ounces BMS 10-11 Type 1 (a) (c) (d) (e) (f) (g) Primer Plus Enamel 24 Ounces BMS 10-72 (a) (c) (d) (e) (f) (g) Primer 24 Ounces BMS 10-79, Type II (a) (c) (d) (e) (f) (g) Topcoat 24 Ounces BMS 10-60, Type II (a) Refer to the Qualified Products List at the end of the Boeing Material Specification (BMS) for supplier data. (b) Refer to SOPM 20-43-03 as an accepted procedure for material sources. (c) This part is only necessary if paint is removed. (d) This part is only necessary if BMS 10-79 and BMS 10-60 or the operators normal decorative paint system is not used. (e) This part is only necessary if BMS 10-72 or the operators normal decorative paint system is not used. (f) Refer to 707 AMM 51-2-141 as an accepted procedure for decorative exterior paint system application. (g) The quantity given is an approximation. The actual quantity required will vary depending on the results of the scribe line inspections.
3. Parts Modified and Reidentified: None. 4. Parts Removed and Not Replaced: None.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 26, 2013 A3539 41 of 110 **BOEING SERVICE BULLETIN A3539 ALERT**  **ALERT D. Parts Necessary to Change Spares**  None. **E. Special Tooling - Price and Availability** The operator can supply the tools shown in Paragraph 2.F., Special Tooling Necessary to do this Service Bulletin. Tool price and supply data are not given. **F. Special Tooling Necessary to do this Service Bulletin** No special tooling is necessary to accomplish this bulletin. However, the following standard tools may be needed to measure scribe line depth. These tools are unusual and may not be available at all shops as standard tools. Maintenance and overhaul tools in the manuals shown in Paragraph 1.J., References, can also be necessary. Examine operator tool supply to make sure all necessary tools are available.
**Name Number**  Digital Optical Micrometer (a) (b) Model Number 8400K Optical Micrometer (a) (c) Model 966 (Part Number 125632-1) or Model 966A (Part Number 125632) Laser Measurement System (d) Inspect Cam Model SDMS These are typical optical micrometers. (a) Rene Company (b) 1005 South Mountain Avenue Monrovia, California 91016 USA Toll free: (866) 358-9955 Tel: (626) 358-9955 Fax: (626) 358-1448 Email: info@renecompany.com Taber Industries (c) 455 Bryant Street North Tonawanda, New York 14120 USA Toll-Free: (800) 333-5300 (in USA or Canada) Phone: (716) 694-4000 Fax: (716) 694-1450 Refer to 707 NDT Manual Part 10, 53-30-01 for the latest vendor information. (d)

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 26, 2013 A3539 42 of 110 **BOEING SERVICE BULLETIN A3539 ALERT**  **ALERT 3. ACCOMPLISHMENT INSTRUCTIONS**  **A. GENERAL INFORMATION CAUTION:**  ELECTRICALLY GROUND THE AIRPLANE. THIS WILL HELP TO PREVENT DAMAGE TO THE AIRPLANE OR EQUIPMENT. **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. 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. 5. Appendix D includes information for the fabrication or purchase of a scribe line sample for use as a training aid. The use of this sample is not required when performing actions of this service bulletin. This sample is an aid in identifying what a scribe line may look and feel like but is not intended to show all damage that is considered a scribe line. When identifying scribe lines, see the definition of a typical scribe line in the Accomplishment Instructions of this service bulletin. 6. If an optical micrometer or laser measurement system cannot be used because the upper skin of the lap joint covers a scribe line, then the scribe line depth does not need to be determined at that location. These scribe lines must be considered typical and therefore all inspection and other requirements for a typical scribe line apply. 7. It is required that individuals performing ultrasonic inspections on airplanes with scribe lines to detect cracks per the relevant procedures must be recognized by the operator or repair station as qualified to perform ultrasonic inspections on their airplanes and meet at least one of the following criteria: – The individual must be qualified to at least Level 2 in the ultrasonic method in accordance with an accepted industry standard, i.e. ATA Specification 105, Mil-Std.-410, NAS-410, SNT-TC-1A, or EN-4179 or equivalent. or – The individual has received specific Boeing training with Boeing providing a certificate stating that the individual has satisfactorily completed the training in the specific techniques. or

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 26, 2013 A3539 43 of 110 **BOEING SERVICE BULLETIN A3539 ALERT**  **ALERT**– The individual has a Level 1 rating in the ultrasonic method in accordance with an accepted industry standard and has received specific training and a statement from the qualifying entity (employer) that the individual is qualified for this particular inspection. 8. If scribe lines are found during any of the inspections contained in this service bulletin, when determining the requirements for inspection and repair, each scribe line shall be considered individually. 9. An external approved repair is identified as any SRM repair, a repair provided and approved by Boeing for a specific case requested by the operator, or an operator developed repair that has a Boeing approved Damage Tolerance Analysis. 10. If a scribe line is found outside of the inspections areas in this service bulletin, do inspections in accordance with Work Instructions, Paragraph 3.B.10 - Part 8. 11. If any scribe line is detected at a non-approved repair, provide details of repair and scribe line to Boeing for evaluation. Do the Boeing recommended disposition. 12. A Detailed Inspection is defined as: An intensive examination of a specific item, installation, or assembly to detect damage, failure, or irregularity. Available lighting is normally supplemented with a direct source of good lighting at an intensity deemed appropriate. Inspection aids such as mirrors, magnifying lenses, etc. may be necessary. Surface cleaning and elaborate procedures may be required. 13. Boeing has developed training video VPS13290, "Preventing Scribe Damage Through Proper Sealant Removal". To get this video, operators should contact their local Boeing Field Service Representative. 14. Operators should thoroughly familiarize themselves with all Parts and Work Instructions in this service bulletin prior to starting their scribe line inspection program. In addition, it is recommended that all Non-Destructive Testing (NDT) procedures be reviewed and limitations understood prior to the use of the NDT inspection. This will aid in understanding all available options in the event a scribe line is discovered. 15. Inspection Exemptions: Certain inspections are not required under these conditions: – Skin Lap Joints: Inspections are not required in skin lap joint areas where an existing external approved repair covers a potential scribe line, provided the repair spans a minimum of three fastener rows above and three fastener rows below the potential scribe line location. External repairs that do not meet this requirement must be removed to allow skin lap joint inspection. – If operator's records show that the airplane has never been stripped or repainted since delivery from Boeing then the skin lap joint and external approved repair scribe line inspections are not required, except as noted below: – If a decal is installed, or was previously installed, across an area that requires inspection, the inspection exemption does not apply. The skin lap joint and external approved repair inspection must still be done for the affected area at the compliance time in accordance with this service bulletin.
16. Do not blend scribe lines. Blending a scribe line may hinder inspection techniques necessary to determine the presence or absence of fatigue cracks.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 26, 2013 A3539 44 of 110 **BOEING SERVICE BULLETIN A3539 ALERT**  **ALERT B. WORK INSTRUCTIONS**  1. IDENTIFICATION OF A "TYPICAL" SCRIBE LINE Determine if the Scribe Line is "typical". A scribe line is defined as a narrow, shallow, distinct line of damage (typically up to 0.006 inch deep), usually associated with the removal of a fillet or gap seal (lap joints and butt joints, respectively). Scribe lines can be both tactile and non-tactile. Discoloration of the aluminum clad layer or small surface imperfections do not qualify as a scribe line. A lightning strike at a lap joint or butt joint does not qualify as a scribe line. In certain cases, the scribe lines have been associated with the trimming of fuselage skin decals. Scribe lines that create a potential safety concern are generally long continuous scribe lines or several adjacent scribe lines in a critical orientation at specific locations with relatively high stresses. If an optical micrometer or laser measurement system cannot be used because the upper skin of the lap joint covers a scribe line, then the scribe line depth does not need to be determined at that location. These scribe lines must be considered typical and therefore all inspection and other requirements for a typical scribe line apply. Grinding, gouging, or other "non-typical" damage, which is more significant (deeper or locally more extensive) than the typical scribe line must be repaired. Localized scratches, nicks and dents that might be induced in other areas of the fuselage skin during either manufacture or maintenance operations are not considered scribe lines. This type of damage should be addressed via the acceptable maintenance practices detailed in the Structural Repair Manual. 2. LOCATIONS OF "TYPICAL" SCRIBE LINES a. Skin Lap Joints In areas near skin lap joints, scribe lines normally run parallel to the lap joint in the lower skin along the edge of the upper skin. These scribe lines are typically within 0.25 inch of the lower edge of the upper skin. In some cases, portions of the scribe lines may be directly adjacent to or slightly under the lower edge of the upper skin resulting in hidden lines that cannot be viewed without disassembly. The ends of these scribe lines sometimes may also turn slightly away from the lap joint. b. Skin Butt Joints In butt joint areas, scribe lines are normally found on the splice plate in the gap between the forward and aft skin edges and run along the butt joint. c. External Approved Repairs In areas around external approved repairs, scribe lines normally follow the periphery of the external approved repairs. d. External Features In areas around external features, scribe lines normally follow the periphery of the external feature.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 26, 2013 A3539 45 of 110 **BOEING SERVICE BULLETIN A3539 ALERT**  **ALERT**e. Decals and Fairings In areas around decals and fairings, scribe lines normally follow the periphery of the decal or fairing. Scribe lines may be located anywhere on a skin panel where decals or fairings are currently installed or were previously were installed. 3. PART 1 - SURFACE PREPARATION - SCRIBE LINE INSPECTIONS **NOTE:** Refer to Appendix A of this service bulletin for an accepted procedure for sealant removal during surface preparation. a. Skin Lap Joint Surface Preparation (1) Remove the sealant from the lower edge of all affected lap joints. (2) Remove the paint from below the lower edge of all affected lap joints. The bared area should be at least one (1.0) inch wide, as measured from the lower edge of the upper skin. (3) If any section of the affected lap joints is under the wing-to-body fairing, remove the appropriate fairing panel(s) for access. b. Skin Butt Joint Surface Preparation Remove the sealant from within the gap of the affected butt joints. It is recommended that the primer and paint, if present, not be removed from the butt joint splice plate. If the primer is removed, do not use chemical stripper. c. External Approved Repair Surface Preparation Remove paint and sealant from the area of the skin around the periphery of the external approved repair. The bared area should be at least one (1.0) inch wide, around the periphery of the external approved repair. d. External Feature Surface Preparation Remove paint and sealant from the area of the skin around the periphery of the external feature. The bared area should be at least one (1.0) inch wide, around the periphery of the external feature. e. Decal and Fairing Surface Preparation Remove the paint from the applicable area of the skin around the edges of the decal or fairing as follows: (1) If decals were previously installed, and it can be determined where the edges of the decals previously were, remove the paint from the area of the skin around the edges of the decal. The bared area should be at least one half (0.5) inch wide on both sides of the edge of the decal. (2) If decals were previously installed, but it cannot be determined where the edges of the decal were, remove the paint from all of the affected decal locations.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 26, 2013 A3539 46 of 110 **BOEING SERVICE BULLETIN A3539 ALERT**  **ALERT**(3) For fairings, remove paint and sealant from the area of the skin around the periphery of the fairing. The bared area should be at least one (1.0) inch wide, around the periphery of the fairing. 4. PART 2 - DETAILED INSPECTION FOR SCRIBE LINES a. Do a detailed inspection of the fuselage skin for scribe lines. Use a minimum 10X magnifying lens to aid the inspection. b. From the tables that follow, which correspond to airplane group numbers, determine the applicable figures for the inspection areas to be inspected. c. If no scribe line is found, do Part 3 - No Scribe Line Found. d. If any scribe line is found, do Part 4 - Scribe Line Found. e. Scribe Line Inspections: **Group 1: Table 1 - Scribe Line Inspections**  **Area** Figure 1 Skin Lap Joints Figure 5 External Approved Repairs Figure 9 External Features **Group 2: Table 2 - Scribe Line Inspections**  **Area** Figure 2 Skin Lap Joints Figure 6 External Approved Repairs Figure 9 External Features **Group 3: Table 3 - Scribe Line Inspections**  **Area** Figure 3 Skin Lap Joints Figure 7 External Approved Repairs Figure 9 External Features **Group 4: Table 4 - Scribe Line Inspections**  **Area** Figure 4 Skin Lap Joints

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 26, 2013 A3539 47 of 110 **BOEING SERVICE BULLETIN A3539 ALERT**  **ALERT Group 4:**  **Table 4 - Scribe Line Inspections Area**  Figure 8 External Approved Repairs Figure 9 External Features **Group 5: Table 5 - Scribe Line Inspections**  **Area** Figure 11 Skin Lap Joints Figure 11 External Approved Repairs Figure 11 External Features Figure 11 Skin Butt Joints Figure 11 Decals
5. PART 3 - NO SCRIBE LINE IS FOUND a. If no scribe lines are found, no further inspections are required. b. Do Part 7 - Surface Finish Restoration. 6. PART 4 - ANY SCRIBE LINE IS FOUND **NOTE:** DO NOT BLEND ANY SCRIBE LINE. BLENDING A SCRIBE LINE MAY HINDER INSPECTION TECHNIQUES NECESSARY TO DETERMINE THE PRESENCE OR ABSENCE OF FATIGUE CRACKS. a. Measure and document the location and depth of all scribe lines that are found. It is recommended that you use the format outlined in Appendix C to document the scribe line. b. Do a laser measurement inspection or the optical micrometer inspection to measure the maximum depth of the scribe line. **NOTE:** Only the laser measurement inspection in accordance with 707 NDT Manual Part 10, 53-30-01 can be used to confirm scribe line depth less than 0.001 inch. c. If the scribe line depth is less than 0.001 inch: (1) No repair or further inspections are required at that location. (2) Do Part 7 - Surface Finish Restoration of this Service Bulletin. d. **Group 1-4:** If the scribe line depth is greater than or equal to 0.001 inch: (1) Do Part 5 - Non-Destructive Testing (NDT) Inspections - Scribe Lines to detect any crack.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 26, 2013 A3539 48 of 110 **BOEING SERVICE BULLETIN A3539 ALERT**  **ALERT NOTE:** The applicable NDT inspection(s) of the scribe line must be accomplished prior to a repair proposal to verify that no crack exists in or around the scribe line. (2) Do Part 7 - Surface Finish Restoration of this Service Bulletin.

e. **Group 5:** If the scribe line depth is greater than or equal to 0.001 inch: (1) Contact Boeing for repair instructions and do the repair. (2) Do Part 7 - Surface Finish Restoration of this Service Bulletin.
7. **Group 1-4:** PART 5 - NON-DESTRUCTIVE TESTING (NDT) INSPECTIONS - SCRIBE LINES If the scribe line depth is greater than or equal to 0.001 inch, do what follows: a. Scribe Line at Skin Lap Joint: (1) Do the applicable NDT inspection in accordance with FIGURE 10. **NOTE:**The skin thickness must be known when conducting the Ultrasonic (UT) inspections so that the correct reference standard is used in calibration. The 707 NDT Manual Part 4, 53-30-05 (Ultrasonic Single Element) has application limitations based upon skin thickness. Use the applicable Boeing drawing to determine skin thickness if skin thickness is not known. (2) If no crack is found and the scribe line depth is greater than or equal to 0.001 inch and less than or equal to 0.006 inch, do one of the options that follows: (a) Do the Limited Return To Service (LRTS) repeat inspection program in accordance with Part 6 of this service bulletin.

or (b) Document and propose a repair to Boeing. Do the repair. This will assist Boeing in the analysis of the scribe line damage and repair proposal. **NOTE:**A repair is not required until the repair compliance time is reached, provided the operator chooses to do the LRTS repeat inspection program in accordance with Part 6 of this service bulletin. A repair proposal is only required if the operator has chosen not to do the LRTS repeat inspection program. (3) If no crack is found and the scribe line depth is greater than 0.006 inch, document and propose a repair to Boeing. Do the repair. This will assist Boeing in the analysis of the scribe line damage and repair proposal. **NOTE:**The LRTS repeat inspection program is not an option for scribe lines greater than 0.006 inch deep.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 26, 2013 A3539 49 of 110 **BOEING SERVICE BULLETIN A3539 ALERT**  **ALERT**(4) If any crack is found, document and propose a repair to Boeing. Do the repair. This will assist Boeing in the analysis of the crack and repair proposal. (5) Do Part 7 - Surface Finish Restoration of this service bulletin. b. Scribe Line at External Approved Repair: (1) Do the applicable NDT inspection in accordance with FIGURE 10. **NOTE:**The skin thickness must be known when conducting the Ultrasonic (UT) inspections so that the correct reference standard is used in calibration. The 707 NDT Manual Part 4, 53-30-05 (Ultrasonic Single Element) has application limitations based upon skin thickness. Use the applicable Boeing drawing to determine skin thickness if skin thickness is not known. (2) If no crack is found and the scribe line depth is greater than or equal to 0.001 inch and less than or equal to 0.006 inch, do one of the options that follows: (a) Do the Limited Return To Service (LRTS) repeat inspection program in accordance with Part 6 of this service bulletin.

or (b) Document and propose a repair to Boeing. Do the repair. This will assist Boeing in the analysis of the scribe line damage and repair proposal. **NOTE:**A repair is not required until the repair compliance time is reached, provided the operator chooses to do the LRTS repeat inspection program in accordance with Part 6 of this service bulletin. A repair proposal is only required if the operator has chosen not to do the LRTS repeat inspection program. (3) If no crack is found and the scribe line depth is greater than 0.006 inch, document and propose a repair to Boeing. Do the repair. This will assist Boeing in the analysis of the scribe line damage and repair proposal. **NOTE:**The LRTS repeat inspection program is not an option for scribe lines greater than 0.006 inch deep. (4) If any crack is found, document and propose a repair to Boeing. Do the repair. This will assist Boeing in the analysis of the crack and repair proposal. (5) Do Part 7 - Surface Finish Restoration of this service bulletin. c. Scribe Line at External Feature: (1) Do the applicable NDT inspection in accordance with FIGURE 10.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 26, 2013 A3539 50 of 110 **BOEING SERVICE BULLETIN A3539 ALERT**  **ALERT NOTE:** The skin thickness must be known when conducting the Ultrasonic (UT) inspections so that the correct reference standard is used in calibration. The 707 NDT Manual Part 4, 53-30-05 (Ultrasonic Single Element) has application limitations based upon skin thickness. Use the applicable Boeing drawing to determine skin thickness if skin thickness is not known. (2) If no crack is found and the scribe line depth is greater than or equal to 0.001 inch and less than or equal to 0.006 inch, do one of the options that follows: (a) Do the Limited Return To Service (LRTS) repeat inspection program in accordance with Part 6 of this service bulletin.

or (b) Document and propose a repair to Boeing. Do the repair. This will assist Boeing in the analysis of the scribe line damage and repair proposal. **NOTE:**A repair is not required until the repair compliance time is reached, provided the operator chooses to do the LRTS repeat inspection program in accordance with Part 6 of this service bulletin. A repair proposal is only required if the operator has chosen not to do the LRTS repeat inspection program. (3) If no crack is found and the scribe line depth is greater than 0.006 inch, document and propose a repair to Boeing. Do the repair. This will assist Boeing in the analysis of the scribe line damage and repair proposal. **NOTE:**The LRTS repeat inspection program is not an option for scribe lines greater than 0.006 inch deep. (4) If any crack is found, document and propose a repair to Boeing. Do the repair. This will assist Boeing in the analysis of the crack and repair proposal. (5) Do Part 7 - Surface Finish Restoration of this service bulletin.
8. **Group 1-4:** PART 6 - LIMITED RETURN TO SERVICE (LRTS) PROGRAM a. Skin Lap Joints - Repeat Inspection: (1) Determine which areas of the skin lap joints require repeat inspection based upon previous inspection results. (2) Do Part 1 - Surface Preparation - Scribe Line Inspection, in areas that require repeat inspection. (3) Do Part 2 - Detailed Inspection for Scribe Lines, in areas that require repeat inspection. (4) Do the applicable NDT inspection in accordance with FIGURE 10.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 26, 2013 A3539 51 of 110 **BOEING SERVICE BULLETIN A3539 ALERT**  **ALERT NOTE:** The skin thickness must be known when conducting the Ultrasonic (UT) inspections so that the correct reference standard is used in calibration. The 707 NDT Manual Part 4, 53-30-05 (Ultrasonic Single Element) has application limitations based upon skin thickness. Use the applicable Boeing drawing to determine skin thickness if skin thickness is not known. (5) If no crack is found, do one of the options that follows: (a) Document and propose a repair to Boeing. Do the repair. This will assist Boeing in the analysis of the scribe line damage and repair proposal.

or (b) Repeat the LRTS program in accordance with this service bulletin. Contact Boeing before the compliance time listed in Paragraph 1.E for additional inspections or repair. Do the additional inspections or repair. (6) If any crack is found, document and propose a repair to Boeing. Do the repair. This will assist Boeing in the analysis of the crack and repair proposal. (7) Do Part 7 - Surface Finish Restoration of this service bulletin. b. External Approved Repair - Repeat Inspection: (1) Determine which areas of the external approved repairs require repeat inspection based upon previous inspection results. (2) Do Part 1 - Surface Preparation - Scribe Line Inspection, in areas that require repeat inspection. (3) Do Part 2 - Detailed Inspection for Scribe Lines, in areas that require repeat inspection. (4) Do the applicable NDT inspection in accordance with FIGURE 10. **NOTE:**The skin thickness must be known when conducting the Ultrasonic (UT) inspections so that the correct reference standard is used in calibration. The 707 NDT Manual Part 4, 53-30-05 (Ultrasonic Single Element) has application limitations based upon skin thickness. Use the applicable Boeing drawing to determine skin thickness if skin thickness is not known. (5) If no crack is found, do one of the options that follows: (a) Document and propose a repair to Boeing. Do the repair. This will assist Boeing in the analysis of the scribe line damage and repair proposal.

or

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 26, 2013 A3539 52 of 110 **BOEING SERVICE BULLETIN A3539 ALERT**  **ALERT**(b) Repeat the LRTS program in accordance with this service bulletin. Contact Boeing before the compliance time listed in Paragraph 1.E for additional inspections or repair. Do the additional inspections or repair. (6) If any crack is found, document and propose a repair to Boeing. Do the repair. This will assist Boeing in the analysis of the crack and repair proposal. (7) Do Part 7 - Surface Finish Restoration of this service bulletin. c. External Features - Repeat Inspection: (1) Determine which areas of the external features require repeat inspection based upon previous inspection results. (2) Do Part 1 - Surface Preparation - Scribe Line Inspection, in areas that require repeat inspection. (3) Do Part 2 - Detailed Inspection for Scribe Lines, in areas that require repeat inspection. (4) Do the applicable NDT inspection in accordance with FIGURE 10. **NOTE:**The skin thickness must be known when conducting the Ultrasonic (UT) inspections so that the correct reference standard is used in calibration. The 707 NDT Manual Part 4, 53-30-05 (Ultrasonic Single Element) has application limitations based upon skin thickness. Use the applicable Boeing drawing to determine skin thickness if skin thickness is not known. (5) If no crack is found, do one of the options that follows: (a) Document and propose a repair to Boeing. Do the repair. This will assist Boeing in the analysis of the scribe line damage and repair proposal.

or (b) Repeat the LRTS program in accordance with this service bulletin. Contact Boeing before the compliance time listed in Paragraph 1.E for additional inspections or repair. Do the additional inspections or repair. (6) If any crack is found, document and propose a repair to Boeing. Do the repair. This will assist Boeing in the analysis of the crack and repair proposal. (7) Do Part 7 - Surface Finish Restoration of this service bulletin. 9. PART 7 - SURFACE FINISH RESTORATION **NOTE:**To reduce the possibility of future scribing, Boeing recommends that the BMS 5-95 fillet seal not be reapplied except as follows: 1. In the gap at butt joints.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 26, 2013 A3539 53 of 110 **BOEING SERVICE BULLETIN A3539 ALERT**  **ALERT**2. The leading edge of the external approved repair for repairs that will be inspected under the LRTS program. 3. Around external features as referred to in the applicable Aircraft Maintenance Manual (AMM) section. a. Refinish the external surface finish as follows: (1) Apply Type 2, Class A chemical conversion coating. Refer to SOPM 20-43-03 as an accepted procedure. (2) Apply BMS 10-72 paint system (primer plus enamel), or BMS 10-79 Type II (primer) plus BMS 10-60 Type II (topcoat), or the operator's normal decorative paint system. Refer to 707 Aircraft Maintenance Manual 51-2-141 as an accepted procedure. b. Refinish the internal surface finish as follows: (1) Apply Type 2, Class A chemical conversion coating. Refer to SOPM 20-43-03 as an accepted procedure. (2) Apply BMS 10-11 Type 1 primer. Refer to 707 Aircraft Maintenance Manual Subject 51-2-141 as an accepted procedure. c. For external approved repairs that will be inspected under the LRTS program, apply a fillet seal of BMS 5-95 sealant at the leading edge of the external approved repair. Refer to 707 Aircraft Maintenance Manual Subject 51-3-0 as an accepted procedure. d. For external approved repairs around which no scribe lines were found, apply a fillet seal of BMS 5-95 sealant around the periphery of the external approved repair. Refer to 707 Aircraft Maintenance Manual Subject 51-3-0 as an accepted procedure. e. Put the airplane back to a serviceable condition.
10. **Group 1-4:** PART 8 - KNOWN EXISTING SCRIBE LINE DAMAGE - OUTSIDE OF SERVICE BULLETIN INSPECTION AREAS If scribe lines are found outside of service bulletin inspection areas, do what follows: a. Do Part 1 - Surface Preparation - Scribe Line Inspections of this service bulletin. b. Measure and document the location and depth of all scribe lines that are found. It is recommended that you use the format outlined in Appendix C to document the scribe line. c. Do a laser measurement inspection or the optical micrometer inspection to measure the maximum depth of the scribe line. **NOTE:** Only the laser measurement inspection in accordance with 707 NDT Manual Part 10, 53-30-01 can be used to confirm scribe line depth less than 0.001 inch. d. If the scribe line depth is less than 0.001 inch: (1) No repair or further inspections are required.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 26, 2013 A3539 54 of 110 **BOEING SERVICE BULLETIN A3539 ALERT**  **ALERT**(2) Do Part 7 - Surface Finish Restoration of this Service Bulletin. e. If the scribe line depth is greater than or equal to 0.001 inch, do what follows: (1) Scribe Line at Skin Lap Joint - NDT Inspection (a) Do the applicable NDT inspection in accordance with FIGURE 10. **NOTE:**The skin thickness must be known when conducting the Ultrasonic (UT) inspections so that the correct reference standard is used in calibration. The 707 NDT Manual Part 4, 53-30-05 (Ultrasonic Single Element) has application limitations based upon skin thickness. Use the applicable Boeing drawing to determine skin thickness if skin thickness is not known. (b) If no crack is found and the scribe line depth is greater than or equal to 0.001 inch and less than or equal to 0.004 inch, no repair or further inspections are required. (c) If no crack is found and the scribe line depth is greater than 0.004 inch and less than or equal to 0.006 inch, contact Boeing for additional inspections or repair. Do the additional inspections or repair. (d) If no crack is found and the scribe line depth is greater than 0.006 inch, document and propose a repair to Boeing. Do the repair. This will assist Boeing in the analysis of the scribe line damage and repair proposal. (e) If any crack is found, document and propose a repair to Boeing. Do the repair. This will assist Boeing in the analysis of the crack and repair proposal. Contact Boeing for additional inspections. Do the additional inspections. (f) Do Part 7 - Surface Finish Restoration of this Service Bulletin. (2) Scribe Line at External Approved Repair - NDT Inspection (a) Do the applicable NDT inspection in accordance with FIGURE 10. **NOTE:**The skin thickness must be known when conducting the Ultrasonic (UT) inspections so that the correct reference standard is used in calibration. The 707 NDT Manual Part 4, 53-30-05 (Ultrasonic Single Element) has application limitations based upon skin thickness. Use the applicable Boeing drawing to determine skin thickness if skin thickness is not known. (b) If no crack is found and the scribe line depth is greater than or equal to 0.001 inch and less than or equal to 0.004 inch, no repair or further inspections are required.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 26, 2013 A3539 55 of 110 **BOEING SERVICE BULLETIN A3539 ALERT**  **ALERT**(c) If no crack is found and the scribe line depth is greater than 0.004 inch and less than or equal to 0.006 inch, contact Boeing for additional inspections or repair. Do the additional inspections or repair. (d) If no crack is found and the scribe line depth is greater than 0.006 inch, document and propose a repair to Boeing. Do the repair. This will assist Boeing in the analysis of the scribe line damage and repair proposal. (e) If any crack is found, document and propose a repair to Boeing. Do the repair. This will assist Boeing in the analysis of the crack and repair proposal. Contact Boeing for additional inspections. Do the additional inspections. (f) Do Part 7 - Surface Finish Restoration of this Service Bulletin. (3) Scribe Line at External Feature - NDT Inspection (a) Do the applicable NDT inspection in accordance with FIGURE 10. **NOTE:**The skin thickness must be known when conducting the Ultrasonic (UT) inspections so that the correct reference standard is used in calibration. The 707 NDT Manual Part 4, 53-30-05 (Ultrasonic Single Element) has application limitations based upon skin thickness. Use the applicable Boeing drawing to determine skin thickness if skin thickness is not known. (b) If no crack is found and the scribe line depth is greater than or equal to 0.001 inch and less than or equal to 0.004 inch, no repair or further inspections are required. (c) If no crack is found and the scribe line depth is greater than 0.004 inch and less than or equal to 0.006 inch, contact Boeing for additional inspections or repair. Do the additional inspections or repair. (d) If no crack is found and the scribe line depth is greater than 0.006 inch, document and propose a repair to Boeing. Do the repair. This will assist Boeing in the analysis of the scribe line damage and repair proposal. (e) If any crack is found, document and propose a repair to Boeing. Do the repair. This will assist Boeing in the analysis of the crack and repair proposal. Contact Boeing for additional inspections. Do the additional inspections. (f) Do Part 7 - Surface Finish Restoration of this Service Bulletin. (4) Scribe Line at Skin Butt Joint - NDT Inspection (a) Based upon scribe line location, do the applicable NDT inspection in accordance with what follows: 1) Low Frequency Eddy Current (LFEC) in accordance with 707 NDT Manual TR 06-10, Part 6, 53-30-24.

or

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 26, 2013 A3539 56 of 110 **BOEING SERVICE BULLETIN A3539 ALERT**  **ALERT**2) High Frequency Eddy Current (HFEC) in accordance with 707 NDT Manual TR 06-11, Part 6, 53-30-25. (b) If no crack is found and the scribe line depth is greater than or equal to 0.001 inch and less than or equal to 0.004 inch, no repair or further inspections are required. (c) If no crack is found and the scribe line depth is greater than 0.004 inch and less than or equal to 0.006 inch, contact Boeing for additional inspections or repair. Do the additional inspections or repair. (d) If no crack is found and the scribe line depth is greater than 0.006 inch, document and propose a repair to Boeing. Do the repair. This will assist Boeing in the analysis of the scribe line damage and repair proposal. (e) If any crack is found, document and propose a repair to Boeing. Do the repair. This will assist Boeing in the analysis of the crack and repair proposal. Contact Boeing for additional inspections. Do the additional inspections. (f) Do Part 7 - Surface Finish Restoration of this Service Bulletin. (5) Scribe Line at Decals and Fairings - NDT Inspection (a) Do a High Frequency Eddy Current (HFEC) inspection in accordance with 707 NDT Manual Part 6, 51-00-00, Figure 4 or 707 NDT Manual Part 6, 51-00-00, Figure 23 to detect any crack at any affected decals and fairings. (b) If no crack is found and the scribe line depth is greater than or equal to 0.001 inch and less than or equal to 0.004 inch, no repair or further inspections are required. (c) If no crack is found and the scribe line depth is greater than 0.004 inch and less than or equal to 0.006 inch, contact Boeing for additional inspections or repair. Do the additional inspections or repair. (d) If no crack is found and the scribe line depth is greater than 0.006 inch, document and propose a repair to Boeing. Do the repair. This will assist Boeing in the analysis of the scribe line damage and repair proposal. (e) If any crack is found, document and propose a repair to Boeing. Do the repair. This will assist Boeing in the analysis of the crack and repair proposal. Contact Boeing for additional inspections. Do the additional inspections. (f) Do Part 7 - Surface Finish Restoration of this Service Bulletin.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 26, 2013 A3539 57 of 110 **BOEING SERVICE BULLETIN A3539 ALERT**  **ALERT This Figure applies only to: Group 1.** 

**FIGURE 1: FUSELAGE - SKIN LAP JOINTS - INSPECTION (SHEET 1 OF 4)** 
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 26, 2013 A3539 58 of 110 **BOEING SERVICE BULLETIN A3539 ALERT**  **ALERT FIGURE 1: FUSELAGE - SKIN LAP JOINTS - INSPECTION**  **(SHEET 2 OF 4)**
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 26, 2013 A3539 59 of 110 **BOEING SERVICE BULLETIN A3539 ALERT**  **ALERT**The step numbers shown below agree with the numbers shown in the circle symbols in the figure. **CAUTION:** DO NOT BLEND SCRIBE LINES. BLENDING A SCRIBE LINE MAY HINDER INSPECTION TECHNIQUES NECESSARY TO DETERMINE THE PRESENCE OR ABSENCE OF FATIGUE CRACKS.
**MORE DATA QTY**  **IDENTIFICATION NAME**  **TASK STEP**  (a) (b)

- S-30R, STA NLG To STA 481 Skin Inspect 1 S-29R, STA 960 To STA 1124.10 S-29R, STA 1124.10 To STA 1265.20 S-25R, STA 312 To STA 360 S-25R, STA 360 To STA 481 S-24R, STA 1364.10 To STA 1440 S-20R, STA 259.50 To STA 360 S-20R, STA 360 To Door Cutout S-20R, STA 580 To STA 600K S-20R, STA 960 To Door Cutout S-20R, Door Cutout To STA 1164.10 S-20R, STA 1164.10 To Door Cutout S-20R, Door Cutout To STA 1265.20 S-14R, STA 360 To Door Cutout S-14R, STA Door Cutout To STA 481 S-14R, STA 1124.10 To STA 1164.10 S-14R, STA 1241 To Door Cutout S-14R, Door Cutout To STA 1364.10 S-10R, STA 1241 To STA 1384.10 S-6R, STA 441 To STA 580 S-6L, STA 441 To STA 481 S-14L, STA 360 To STA 481 S-14L, STA 1220 To Door Cutout S-20L, STA 259.50 To STA 360 S-20L, STA 360 To STA 600

**FIGURE 1: FUSELAGE - SKIN LAP JOINTS - INSPECTION (SHEET 3 OF 4)** 
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 26, 2013 A3539 60 of 110 **BOEING SERVICE BULLETIN A3539 ALERT**  **ALERT MORE DATA**  **QTY IDENTIFICATION**  **NAME TASK**  **STEP** S-20L, STA 960 To STA 1164.10 S-20L, STA 1164.10 To STA 1265.20 S-25L, STA 312 To STA 360 S-25L, STA 441 To STA 481 S-29L, STA 960 To STA 1124.10 S-29L, STA 1124.10 To STA 1265.20 (a) Do a detailed inspection of the fuselage skin for any scribe line. Use a minimum 10X magnifying lens to aid the inspection. (b) In areas near lap joints, scribe lines normally run parallel to the lap joint in the lower skin along the edge of the upper skin. These scribe lines are typically within 0.25 inch of the lower edge of the upper skin. In some cases, portions of the scribe lines may be directly adjacent to or slightly under the lower edge of the upper skin. The ends of these scribe lines sometimes may also turn slightly away from the lap joint.

**FIGURE 1: FUSELAGE - SKIN LAP JOINTS - INSPECTION (SHEET 4 OF 4)** 
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 26, 2013 A3539 61 of 110 **BOEING SERVICE BULLETIN A3539 ALERT**  **ALERT This Figure applies only to: Group 2.** 

**FIGURE 2: FUSELAGE - SKIN LAP JOINTS - INSPECTION (SHEET 1 OF 4)** 
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 26, 2013 A3539 62 of 110 **BOEING SERVICE BULLETIN A3539 ALERT**  **ALERT FIGURE 2: FUSELAGE - SKIN LAP JOINTS - INSPECTION**  **(SHEET 2 OF 4)**
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 26, 2013 A3539 63 of 110 **BOEING SERVICE BULLETIN A3539 ALERT**  **ALERT**The step numbers shown below agree with the numbers shown in the circle symbols in the figure. **CAUTION:** DO NOT BLEND SCRIBE LINES. BLENDING A SCRIBE LINE MAY HINDER INSPECTION TECHNIQUES NECESSARY TO DETERMINE THE PRESENCE OR ABSENCE OF FATIGUE CRACKS.
**MORE DATA QTY**  **IDENTIFICATION NAME**  **TASK STEP**  (a) (b)

- S-30R, STA NLG To STA 481 Skin Inspect 1 S-29R, STA 960 To STA 1124.10 S-29R, STA 1124.10 To STA 1265.20 S-25R, STA 312 To STA 360 S-25R, STA 360 To STA 481 S-24R, STA 1364.10 To STA 1440 S-20R, STA 259.50 To STA 360 S-20R, STA 360 To Door Cutout S-20R, STA 580 To STA 600K S-20R, STA 960 To Door Cutout S-20R, Door Cutout To STA 1164.10 S-20R, STA 1164.10 To Door Cutout S-20R, Door Cutout To STA 1265.20 S-14R, STA 360 To Door Cutout S-14R, Door Cutout To STA 481 S-14R, STA 1124.10 To STA 1164.10 S-14R, STA 1241 To Door Cutout S-14R, Door Cutout To STA 1364.10 S-10R, STA 1241 To STA 1384.10 S-6R, STA 441 To STA 580 S-6L, STA 441 To STA 481 S-14L, STA 360 To STA 481 S-14L, STA 1220 To Door Cutout S-20L, STA 259.50 To STA 360 S-20L, STA 360 To STA 441 S-20L, STA 441 To STA 600H

**FIGURE 2: FUSELAGE - SKIN LAP JOINTS - INSPECTION (SHEET 3 OF 4)** 
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 26, 2013 A3539 64 of 110 **BOEING SERVICE BULLETIN A3539 ALERT**  **ALERT MORE DATA**  **QTY IDENTIFICATION**  **NAME TASK**  **STEP** S-20L, STA 960 To STA 1164.10 S-20L, STA 1164.10 To STA 1265.20 S-25L, STA 312 To STA 360 S-25L, STA 441 To STA 481 S-29L, STA 960 To STA 1124.10 S-29L, STA 1124.10 To STA 1265.20 (a) Do a detailed inspection of the fuselage skin for any scribe line. Use a minimum 10X magnifying lens to aid the inspection. (b) In areas near lap joints, scribe lines normally run parallel to the lap joint in the lower skin along the edge of the upper skin. These scribe lines are typically within 0.25 inch of the lower edge of the upper skin. In some cases, portions of the scribe lines may be directly adjacent to or slightly under the lower edge of the upper skin. The ends of these scribe lines sometimes may also turn slightly away from the lap joint.

**FIGURE 2: FUSELAGE - SKIN LAP JOINTS - INSPECTION (SHEET 4 OF 4)** 
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 26, 2013 A3539 65 of 110 **BOEING SERVICE BULLETIN A3539 ALERT**  **ALERT This Figure applies only to: Group 3.** 

**FIGURE 3: FUSELAGE - SKIN LAP JOINTS - INSPECTION (SHEET 1 OF 4)** 
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 26, 2013 A3539 66 of 110 **BOEING SERVICE BULLETIN A3539 ALERT**  **ALERT FIGURE 3: FUSELAGE - SKIN LAP JOINTS - INSPECTION**  **(SHEET 2 OF 4)**
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 26, 2013 A3539 67 of 110 **BOEING SERVICE BULLETIN A3539 ALERT**  **ALERT**The step numbers shown below agree with the numbers shown in the circle symbols in the figure. **CAUTION:** DO NOT BLEND SCRIBE LINES. BLENDING A SCRIBE LINE MAY HINDER INSPECTION TECHNIQUES NECESSARY TO DETERMINE THE PRESENCE OR ABSENCE OF FATIGUE CRACKS.
**MORE DATA QTY**  **IDENTIFICATION NAME**  **TASK STEP**  (a) (b)

- S-30R, STA NLG To STA 481 Skin Inspect 1 S-29R, STA 960 To STA 1124.10 S-29R, STA 1124.10 To STA 1265.20 S-25R, STA 312 To STA 360 S-25R, STA 360 To STA 481 S-24R, STA 1364.10 To STA 1440 S-20R, STA 259.50 To STA 360 S-20R, STA 360 To Door Cutout S-20R, STA 580 To STA 600K S-20R, STA 960 To Door Cutout S-20R, Door Cutout To STA 1164.10 S-20R, STA 1164.10 To Door Cutout S-20R, Door Cutout To STA 1265.20 S-14R, STA 360 To Door Cutout S-14R, Door Cutout To STA 481 S-14R, STA 1124.10 To STA 1164.10 S-14R, STA 1241 To Door Cutout S-14R, Door Cutout To STA 1364.10 S-10R, STA 1241 To STA 1384.10 S-6R, STA 441 To STA 580 S-6L, STA 441 To STA 481 S-14L, STA 360 To STA 481 S-14L, STA 1220 To Door Cutout S-20L, STA 259.50 To STA 360 S-20L, STA 360 To STA 441 S-20L, STA 441 To STA 600H

**FIGURE 3: FUSELAGE - SKIN LAP JOINTS - INSPECTION (SHEET 3 OF 4)** 
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 26, 2013 A3539 68 of 110 **BOEING SERVICE BULLETIN A3539 ALERT**  **ALERT MORE DATA**  **QTY IDENTIFICATION**  **NAME TASK**  **STEP** S-20L, STA 960 To STA 1164.10 S-20L, STA 1164.10 To STA 1265.20 S-25L, STA 312 To STA 360 S-25L, STA 441 To STA 481 S-29L, STA 960 To STA 1124.10 S-29L, STA 1124.10 To STA 1265.20 (a) Do a detailed inspection of the fuselage skin for any scribe line. Use a minimum 10X magnifying lens to aid the inspection. (b) In areas near lap joints, scribe lines normally run parallel to the lap joint in the lower skin along the edge of the upper skin. These scribe lines are typically within 0.25 inch of the lower edge of the upper skin. In some cases, portions of the scribe lines may be directly adjacent to or slightly under the lower edge of the upper skin. The ends of these scribe lines sometimes may also turn slightly away from the lap joint.

**FIGURE 3: FUSELAGE - SKIN LAP JOINTS - INSPECTION (SHEET 4 OF 4)** 
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 26, 2013 A3539 69 of 110 **BOEING SERVICE BULLETIN A3539 ALERT**  **ALERT This Figure applies only to: Group 4.** 

**FIGURE 4: FUSELAGE - SKIN LAP JOINTS - INSPECTION (SHEET 1 OF 4)** 
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 26, 2013 A3539 70 of 110 **BOEING SERVICE BULLETIN A3539 ALERT**  **ALERT FIGURE 4: FUSELAGE - SKIN LAP JOINTS - INSPECTION**  **(SHEET 2 OF 4)**
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 26, 2013 A3539 71 of 110 **BOEING SERVICE BULLETIN A3539 ALERT**  **ALERT**The step numbers shown below agree with the numbers shown in the circle symbols in the figure. **CAUTION:** DO NOT BLEND SCRIBE LINES. BLENDING A SCRIBE LINE MAY HINDER INSPECTION TECHNIQUES NECESSARY TO DETERMINE THE PRESENCE OR ABSENCE OF FATIGUE CRACKS.
**MORE DATA QTY**  **IDENTIFICATION NAME**  **TASK STEP**  (a) (b)

- S-30R, STA NLG To STA 481 Skin Inspect 1 S-29R, STA 960 To STA 1124.10 S-29R, STA 1124.10 To STA 1265.20 S-25R, STA 312 To STA 360 S-25R, STA 360 To STA 481 S-24R, STA 1364.10 To STA 1440 S-20R, STA 259.50 To STA 360 S-20R, STA 360 To Door Cutout S-20R, STA 580 To STA 600K S-20R, STA 960 To Door Cutout S-20R, Door Cutout To STA 1164.10 S-20R, STA 1164.10 To Door Cutout S-20R, Door Cutout To STA 1265.20 S-14R, STA 360 To Door Cutout S-14R, Door Cutout To STA 481 S-14R, STA 1124.10 To STA 1164.10 S-14R, STA 1241 To Door Cutout S-14R, Door Cutout To STA 1364.10 S-10R, STA 1241 To STA 1384.10 S-6R, STA 441 To STA 580 S-6L, STA 441 To Door Cutout S-14L, STA 360 To Door Cutout S-14L, STA 1220 To Door Cutout S-20L, STA 259.50 To STA 360 S-20L, STA 360 To STA 441 S-20L, STA 600E To STA 600H

**FIGURE 4: FUSELAGE - SKIN LAP JOINTS - INSPECTION (SHEET 3 OF 4)** 
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 26, 2013 A3539 72 of 110 **BOEING SERVICE BULLETIN A3539 ALERT**  **ALERT MORE DATA**  **QTY IDENTIFICATION**  **NAME TASK**  **STEP** S-20L, STA 960 To STA 1164.10 S-20L, STA 1164.10 To STA 1265.20 S-25L, STA 312 To STA 360 S-25L, STA 441 To STA 481 S-29L, STA 960 To STA 1144.10 S-29L, STA 1144.10 To STA 1265.20 (a) Do a detailed inspection of the fuselage skin for any scribe line. Use a minimum 10X magnifying lens to aid the inspection. (b) In areas near lap joints, scribe lines normally run parallel to the lap joint in the lower skin along the edge of the upper skin. These scribe lines are typically within 0.25 inch of the lower edge of the upper skin. In some cases, portions of the scribe lines may be directly adjacent to or slightly under the lower edge of the upper skin. The ends of these scribe lines sometimes may also turn slightly away from the lap joint.

**FIGURE 4: FUSELAGE - SKIN LAP JOINTS - INSPECTION (SHEET 4 OF 4)** 
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 26, 2013 A3539 73 of 110 **BOEING SERVICE BULLETIN A3539 ALERT**  **ALERT This Figure applies only to: Group 1.** 

**FIGURE 5: FUSELAGE - EXTERNAL APPROVED REPAIRS - INSPECTION (SHEET 1 OF 3)** 
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 26, 2013 A3539 74 of 110 **BOEING SERVICE BULLETIN A3539 ALERT**  **ALERT FIGURE 5: FUSELAGE - EXTERNAL APPROVED REPAIRS - INSPECTION**  **(SHEET 2 OF 3)**
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 26, 2013 A3539 75 of 110 **BOEING SERVICE BULLETIN A3539 ALERT**  **ALERT**The step numbers shown below agree with the numbers shown in the circle symbols in the figure. **CAUTION:** DO NOT BLEND SCRIBE LINES. BLENDING A SCRIBE LINE MAY HINDER INSPECTION TECHNIQUES NECESSARY TO DETERMINE THE PRESENCE OR ABSENCE OF FATIGUE CRACKS.
**MORE DATA QTY**  **IDENTIFICATION NAME**  **TASK STEP**  (a) (b) (c)

- STA 259.50 To STA 1440 - S30R To S30L Skin Inspect 1 (a) Do a detailed inspection of the fuselage skin around external approved repairs for any scribe line. Use a minimum 10X magnifying lens to aid the inspection. (b) Scribe lines normally run parallel to the external approved repair along the edge of the repair. These scribe lines are typically within 0.25 inch of the repair. In some cases, portions of the scribe lines may be directly adjacent to or slightly under the edge of the repair. (c) If the repair ends at a butt splice, inspect the butt splice strap at the repair area plus ten (10) inches above and below the repair.

**FIGURE 5: FUSELAGE - EXTERNAL APPROVED REPAIRS - INSPECTION (SHEET 3 OF 3)** 
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 26, 2013 A3539 76 of 110 **BOEING SERVICE BULLETIN A3539 ALERT**  **ALERT This Figure applies only to: Group 2.** 

**FIGURE 6: FUSELAGE - EXTERNAL APPROVED REPAIRS - INSPECTION (SHEET 1 OF 3)** 
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 26, 2013 A3539 77 of 110 **BOEING SERVICE BULLETIN A3539 ALERT**  **ALERT FIGURE 6: FUSELAGE - EXTERNAL APPROVED REPAIRS - INSPECTION**  **(SHEET 2 OF 3)**
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 26, 2013 A3539 78 of 110 **BOEING SERVICE BULLETIN A3539 ALERT**  **ALERT**The step numbers shown below agree with the numbers shown in the circle symbols in the figure. **CAUTION:** DO NOT BLEND SCRIBE LINES. BLENDING A SCRIBE LINE MAY HINDER INSPECTION TECHNIQUES NECESSARY TO DETERMINE THE PRESENCE OR ABSENCE OF FATIGUE CRACKS.
**MORE DATA QTY**  **IDENTIFICATION NAME**  **TASK STEP**  (a) (b) (c)

- STA 259.50 To STA 1440 - S30R To S30L Skin Inspect 1 (a) Do a detailed inspection of the fuselage skin around external approved repairs for any scribe line. Use a minimum 10X magnifying lens to aid the inspection. (b) Scribe lines normally run parallel to the external approved repair along the edge of the repair. These scribe lines are typically within 0.25 inch of the repair. In some cases, portions of the scribe lines may be directly adjacent to or slightly under the edge of the repair. (c) If the repair ends at a butt splice, inspect the butt splice strap at the repair area plus ten (10) inches above and below the repair.

**FIGURE 6: FUSELAGE - EXTERNAL APPROVED REPAIRS - INSPECTION (SHEET 3 OF 3)** 
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 26, 2013 A3539 79 of 110 **BOEING SERVICE BULLETIN A3539 ALERT**  **ALERT This Figure applies only to: Group 3.** 

**FIGURE 7: FUSELAGE - EXTERNAL APPROVED REPAIRS - INSPECTION (SHEET 1 OF 3)** 
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 26, 2013 A3539 80 of 110 **BOEING SERVICE BULLETIN A3539 ALERT**  **ALERT FIGURE 7: FUSELAGE - EXTERNAL APPROVED REPAIRS - INSPECTION**  **(SHEET 2 OF 3)**
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 26, 2013 A3539 81 of 110 **BOEING SERVICE BULLETIN A3539 ALERT**  **ALERT**The step numbers shown below agree with the numbers shown in the circle symbols in the figure. **CAUTION:** DO NOT BLEND SCRIBE LINES. BLENDING A SCRIBE LINE MAY HINDER INSPECTION TECHNIQUES NECESSARY TO DETERMINE THE PRESENCE OR ABSENCE OF FATIGUE CRACKS.
**MORE DATA QTY**  **IDENTIFICATION NAME**  **TASK STEP**  (a) (b) (c)

- STA 259.50 To STA 1440 - S30R To S30L Skin Inspect 1 (a) Do a detailed inspection of the fuselage skin around external approved repairs for any scribe line. Use a minimum 10X magnifying lens to aid the inspection. (b) Scribe lines normally run parallel to the external approved repair along the edge of the repair. These scribe lines are typically within 0.25 inch of the repair. In some cases, portions of the scribe lines may be directly adjacent to or slightly under the edge of the repair. (c) If the repair ends at a butt splice, inspect the butt splice strap at the repair area plus ten (10) inches above and below the repair.

**FIGURE 7: FUSELAGE - EXTERNAL APPROVED REPAIRS - INSPECTION (SHEET 3 OF 3)** 
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 26, 2013 A3539 82 of 110 **BOEING SERVICE BULLETIN A3539 ALERT**  **ALERT This Figure applies only to: Group 4.** 

**FIGURE 8: FUSELAGE - EXTERNAL APPROVED REPAIRS - INSPECTION (SHEET 1 OF 3)** 
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 26, 2013 A3539 83 of 110 **BOEING SERVICE BULLETIN A3539 ALERT**  **ALERT FIGURE 8: FUSELAGE - EXTERNAL APPROVED REPAIRS - INSPECTION**  **(SHEET 2 OF 3)**
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 26, 2013 A3539 84 of 110 **BOEING SERVICE BULLETIN A3539 ALERT**  **ALERT**The step numbers shown below agree with the numbers shown in the circle symbols in the figure. **CAUTION:** DO NOT BLEND SCRIBE LINES. BLENDING A SCRIBE LINE MAY HINDER INSPECTION TECHNIQUES NECESSARY TO DETERMINE THE PRESENCE OR ABSENCE OF FATIGUE CRACKS.
**MORE DATA QTY**  **IDENTIFICATION NAME**  **TASK STEP**  (a) (b) (c)

- STA 259.50 To STA 1440 - S30R To S30L Skin Inspect 1 (a) Do a detailed inspection of the fuselage skin around external approved repairs for any scribe line. Use a minimum 10X magnifying lens to aid the inspection. (b) Scribe lines normally run parallel to the external approved repair along the edge of the repair. These scribe lines are typically within 0.25 inch of the repair. In some cases, portions of the scribe lines may be directly adjacent to or slightly under the edge of the repair. (c) If the repair ends at a butt splice, inspect the butt splice strap at the repair area plus ten (10) inches above and below the repair.

**FIGURE 8: FUSELAGE - EXTERNAL APPROVED REPAIRS - INSPECTION (SHEET 3 OF 3)** 
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 26, 2013 A3539 85 of 110 **BOEING SERVICE BULLETIN A3539 ALERT**  **ALERT This Figure applies only to: Group 1-4.** 

**FIGURE 9: FUSELAGE - EXTERNAL FEATURES - INSPECTION (SHEET 1 OF 3)** 
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 26, 2013 A3539 86 of 110 **BOEING SERVICE BULLETIN A3539 ALERT**  **ALERT FIGURE 9: FUSELAGE - EXTERNAL FEATURES - INSPECTION**  **(SHEET 2 OF 3)**
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 26, 2013 A3539 87 of 110 **BOEING SERVICE BULLETIN A3539 ALERT**  **ALERT**The step numbers shown below agree with the numbers shown in the circle symbols in the figure. **CAUTION:** DO NOT BLEND SCRIBE LINES. BLENDING A SCRIBE LINE MAY HINDER INSPECTION TECHNIQUES NECESSARY TO DETERMINE THE PRESENCE OR ABSENCE OF FATIGUE CRACKS.
**MORE DATA QTY**  **IDENTIFICATION NAME**  **TASK STEP**  (a) (b) (c) 1 S-25L To S-25R, STA 294.50 To STA 312 Air Traffic Control / L-Band Antenna Inspect 1

1 S-30L To S-30R, STA 1010 Antenna - LowRange Radio Altimeter 1 S-30L To S-30R, STA 1029 Antenna - LowRange Radio Altimeter 1 S-30L To S-30R, STA 1050 Antenna - LowRange Radio Altimeter 1 S-30L To S-30R, STA 1069 Antenna - LowRange Radio Altimeter Side (a) Do a detailed inspection of the fuselage skin around the external feature for any scribe line. Use a minimum 10X magnifying lens to aid the inspection. (b) In areas around external features, scribe lines normally follow the periphery of the external feature. (c) Location may vary among operators.

**FIGURE 9: FUSELAGE - EXTERNAL FEATURES - INSPECTION (SHEET 3 OF 3)** 
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 26, 2013 A3539 88 of 110 **BOEING SERVICE BULLETIN A3539 ALERT**  **ALERT This Figure applies only to: Group 1-4.** 

In each of the areas defined above, all of the inspections described in the table are necessary if scribes are found. The Illustration shown above is not to scale. Initial inspections must be done with the paint removed. **Area 3 Inspections Area 2 Inspections (h)**  **Area 1 Inspections (h)** Skin Lap Joint locations - If any scribe lines are found in Area 3, all of the following inspections must be done in Area 3. (f) Butt joint to butt joint inspections are not required in Area 3. Skin Lap Joint locations - If any scribe lines are found in Area 2, all of the following inspections must be done in Area 2. (f) Butt joint to butt joint inspections are not required in Area 2. Skin Lap Joint locations - If any scribe lines are found in Area 1 orArea 2, all of the following inspections must be done in Area 1 from butt joint to butt joint at the skin lap joint location. (a) (g) External Approved Repairs locations - If any scribe lines are in Area 3, all of the following inspections must be done in Area 3. (f) It is not required to inspect the entire periphery of the external approved repair location in Area 3. External Approved Repairs locations - If any scribe lines are in Area 2, all of the following inspections must be done in Area 2. (f) It is not required to inspect the entire periphery of the external approved repair location in Area 2. External Approved Repairs locations - If any scribe lines are in Area 1 orArea 2, all of the following inspections must be done in Area 1 along the entire periphery of the external approved repair location.

**FIGURE 10: FUSELAGE - SKIN LAP JOINTS, EXTERNAL APPROVED REPAIRS, AND EXTERNAL FEATURES - NON-DESTRUCTIVE TESTING INSPECTIONS**  **(SHEET 1 OF 2)**
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 26, 2013 A3539 89 of 110 **BOEING SERVICE BULLETIN A3539 ALERT**  **ALERT Area 3 Inspections**  **Area 2 Inspections (h) Area 1 Inspections (h)**  External Feature locations - If any scribe lines are in Area 3, all of the following inspections must be donein Area 3. (f) It is not required to inspect the entire periphery of the external feature location in Area 3. External Feature locations - If any scribe lines are in Area 2, all of the following inspections must be donein Area 2. (f) It is not required to inspect the entire periphery of the external feature location in Area 2. External Feature locations - If any scribe lines are in Area 1 or Area 2, all of the following inspections mustbe done in Area 1 along the periphery of the external feature location. High Frequency Eddy Current (HFEC) below High Frequency Eddy Current (HFEC) below. Option 1 or Option 2 below.
Surface HFEC in accordance with 707 NDT Manual Part 6, 51-00-00, Figure 4 (b) (f) Surface HFEC in accordance with 707 NDT Manual Part 6, 51-00-00, Figure 4 (b) (f) Option 1: Ultrasonic (UT) Single Element in accordance with 707 NDT Manual Part 4, 53-30-05 (c) (d) or or and Surface HFEC in accordance with 707 NDT Manual Part 6, 51-00-00, Figure 23 (b) (f) Surface HFEC in accordance with 707 NDT Manual Part 6, 51-00-00, Figure 23 (b) (f)Surface High Frequency Eddy Current (HFEC) in accordance with 707 NDT Manual Part 6, 53-30-22 (b) or Eddy Current Array Inspection in accordance with 707 NDT Manual TR 06-12, Part 6, 53-30-26 (Skin Lap Joint locations only) (b) or Eddy Current Array Inspection in accordance with 707 NDT Manual TR 06-12, Part 6, 53-30-26 (Skin Lap Joint locations only) (b) Option 2:Ultrasonic (UT) Phased Array in accordance with 707 NDT Manual Part 4, 53-30-06 (b) (e) (a) If a door cutout breaks up a skin panel between butt joints, then do inspection from butt joint to door cutout instead of butt joint to butt joint. (b) After the initial inspection with the paint removed, subsequent Limited Return to Service (LRTS) inspections using this method can be done with the paint in place. For the ultrasonic phased array inspection, paint thickness must be less than or equal to 0.007 inch thick if paint is left in place. (c) The paint must be removed for this inspection. (d) The Ultrasonic (UT) Single Element inspection method can detect cracks at scribe lines up to 0.030 inch under the edge of the overlapping skin, external approved repair, or external feature. (e) The Ultrasonic (UT) Phased Array inspection method can detect cracks at scribe lines up to 0.030 inch under the edge of the overlapping skin, external approved repair, or external feature and up to 0.063 inch beyond the edge of the overlapping skin, external approved repair, or external feature. (f) This inspection is only required locally where scribe lines exist. (g) For the Limited Return to Service (LRTS) program, areas along skin lap joints that require butt joint to butt joint inspections do not need to be inspected at the same time; each area may be inspected independently at its associated LRTS inspection interval. The LRTS inspection for each area may be delayed until the actual compliance time in which each area is located. For areas outside of the service bulletin inspection areas, refer to Table 8 of the Compliance section of this service bulletin. This note does not apply for initial inspections. (h) At skin lap joints, Area 1 inspections are required from butt joint to butt joint or door opening if any scribe line is found within Area 1 or Area 2.

**FIGURE 10: FUSELAGE - SKIN LAP JOINTS, EXTERNAL APPROVED REPAIRS, AND EXTERNAL FEATURES - NON-DESTRUCTIVE TESTING INSPECTIONS**  **(SHEET 2 OF 2)**
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 26, 2013 A3539 90 of 110 **BOEING SERVICE BULLETIN A3539 ALERT**  **ALERT This Figure applies only to: Group 5.** 

**FIGURE 11: FUSELAGE - SKIN LAP JOINTS, EXTERNAL APPROVED REPAIRS, EXTERNAL FEATURES, SKIN BUTT JOINTS AND DECALS - INSPECTION**  **(SHEET 1 OF 6)**
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 26, 2013 A3539 91 of 110 **BOEING SERVICE BULLETIN A3539 ALERT**  **ALERT FIGURE 11: FUSELAGE - SKIN LAP JOINTS, EXTERNAL APPROVED REPAIRS, EXTERNAL FEATURES,**  **SKIN BUTT JOINTS AND DECALS - INSPECTION (SHEET 2 OF 6)** 
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 26, 2013 A3539 92 of 110 **BOEING SERVICE BULLETIN A3539 ALERT**  **ALERT FIGURE 11: FUSELAGE - SKIN LAP JOINTS, EXTERNAL APPROVED REPAIRS, EXTERNAL FEATURES,**  **SKIN BUTT JOINTS AND DECALS - INSPECTION (SHEET 3 OF 6)** 
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 26, 2013 A3539 93 of 110 **BOEING SERVICE BULLETIN A3539 ALERT**  **ALERT FIGURE 11: FUSELAGE - SKIN LAP JOINTS, EXTERNAL APPROVED REPAIRS, EXTERNAL FEATURES,**  **SKIN BUTT JOINTS AND DECALS - INSPECTION (SHEET 4 OF 6)** 
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 26, 2013 A3539 94 of 110 **BOEING SERVICE BULLETIN A3539 ALERT**  **ALERT**The step numbers shown below agree with the numbers shown in the circle symbols in the figure. **CAUTION:** DO NOT BLEND SCRIBE LINES. BLENDING A SCRIBE LINE MAY HINDER INSPECTION TECHNIQUES NECESSARY TO DETERMINE THE PRESENCE OR ABSENCE OF FATIGUE CRACKS.
**MORE DATA QTY**  **IDENTIFICATION NAME**  **TASK STEP**  (a) (b) All STA 178 To STA 1440 - S30R To S30L Skin Lap Joints Inspect 1 (c) (d) (e) All STA 178 To STA 1440 - S30R To S30L External Approved Repairs Inspect 2 (f) (g) (h) All STA 178 To STA 1440 - S30R To S30L External Features Inspect 3 (i) (j) All STA 178 To STA 1440 - S30R To S30L Skin Butt Joints Inspect 4 (k) (l) All STA 178 To STA 1440 - S30R To S30L Decals Inspect 5 (a) Do a detailed inspection of all skin lap joints on the fuselage skin for any scribe line. Use a minimum 10X magnifying lens to aid the inspection. (b) In areas near lap joints, scribe lines normally run parallel to the lap joint in the lower skin along the edge of the upper skin. These scribe lines are typically within 0.25 inch of the lower edge of the upper skin. In some cases, portions of the scribe lines may be directly adjacent to or slightly under the lower edge of the upper skin. The ends of these scribe lines sometimes may also turn slightly away from the lap joint. (c) Do a detailed inspection around all external approved repairs on the fuselage skin for any scribe line. Use a minimum 10X magnifying lens to aid the inspection. (d) Scribe lines normally run parallel to the external approved repair along the edge of the repair. These scribe lines are typically within 0.25 inch of the repair. In some cases, portions of the scribe lines may be directly adjacent to or slightly under the edge of the repair. (e) If the repair ends at a butt splice, inspect the butt splice strap at the repair area plus ten (10) inches above and below the repair. (f) Do a detailed inspection around all external features on the fuselage skin for any scribe line. Use a minimum 10X magnifying lens to aid the inspection. (g) In areas around external features, scribe lines normally follow the periphery of the external feature. (h) Location may vary among operators.(i) Do a detailed inspection around all skin butt joints on the fuselage skin for any scribe line. Use a minimum 10X magnifying lens to aid the inspection. (j) Scribe lines at butt joints are normally found on the splice plate in the gap between the forward and aft skin edges and run along the skin butt joint. In addition, scribe lines normally run parallel to the skin butt joint. In some cases, portions of the scribe lines may be directly adjacent to the edge of the fuselage skin.

**FIGURE 11: FUSELAGE - SKIN LAP JOINTS, EXTERNAL APPROVED REPAIRS, EXTERNAL FEATURES, SKIN BUTT JOINTS AND DECALS - INSPECTION**  **(SHEET 5 OF 6)**
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 26, 2013 A3539 95 of 110 **BOEING SERVICE BULLETIN A3539 ALERT**  **ALERT MORE DATA**  **QTY IDENTIFICATION**  **NAME TASK**  **STEP** (k) Do a detailed inspection around all decals on the fuselage skin for any scribe line. Use a minimum 10X magnifying lens to aid the inspection. (l) In areas around decals, scribe lines normally follow the periphery of the decal.

**FIGURE 11: FUSELAGE - SKIN LAP JOINTS, EXTERNAL APPROVED REPAIRS, EXTERNAL FEATURES, SKIN BUTT JOINTS AND DECALS - INSPECTION**  **(SHEET 6 OF 6)**
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 26, 2013 A3539 96 of 110 **BOEING SERVICE BULLETIN A3539 ALERT**  **ALERT**1. MATERIAL AND EQUIPMENT a. Scrapers (1) AC Tech Scraper, TS 1275-4 (6 inch length) Supplier: Advanced Chemistry & Technology (AC TECH) Address: 7341 Anaconda Avenue, Garden Grove, California 92841, USA Phone: (714) 373-2837 extension 119 or 117 Fax: (714) 373-1913 Attn: Customer Service email: rosie.cruze@actechaero.com **NOTE:** Handles are also available for these products for better comfort and control. The handle best suited for the TS 1275-4 scraper can be purchased under the part number SHR 0272-T from AC Tech. (2) SEMCO Scraper: P/N 234350 (6 inch length) Supplier: PPG Aerospace: SEMCO Division Address: PPG Aerospace (ASC-Seattle), 14126 NE 190th Street, Woodinville, Washington 98072, USA Phone: North America (800) 237-6649 (This connects to the closest PPG Aerospace facility in North America. For North America and International contacts visit the web site.) China (Suzhou) 86 512 6661 5858 Dubai UAE 971 4 883 9666 France 33 0 5 6149 4849 Germany 49 40 742 193 10 Hong Kong 852 2861 0918 South Africa 27 11 608 5656 Singapore 65 861 1119 United Kingdom 44 0 1388 770222 Web Site: www.ppg.com/prc-desoto/main

**Appendix A: SEALANT REMOVAL PROCEDURE FOR EXTERIOR PRESSURIZED FUSELAGE SKIN (SHEET 1 OF 8)** 
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 26, 2013 A3539 97 of 110 **BOEING SERVICE BULLETIN A3539 ALERT**  **ALERT**email: Cheryl.Chittenden@PPG.com subject=Semco Scrapers (PN-234350) (3) Jus N Tyme Scrapers: P/N JNT 411B60 (6 inch length), P/N JNT 411B90 (9 inch length -tapered) Supplier: Jus N Tyme Tooling Address: 2167 Green Canyon Road, Fallbrook, California 92028, USA Phone: (760) 723-5985 Fax: (760) 723-5820 Contacts: Cheryl or Bob Hancock Web Site: www.JusNTyme.com email: Bob@JusNTyme.com **NOTE:** Scraper P/N JNT 411B90 is designed for removing sealant from butt joints with a 1/4 inch or larger gap. (4) PnJ Scrapers: P/N DFD5019, SCD5019, SFD7519, DAD5013 (5 and 9 inch lengths of varying widths); Plastic handles: P/N SHN0272, SHW0215, SHR0272 Supplier: PnJ Machining, Inc. Address: 2601 Inter Avenue, Puyallup, Washington 98372, USA Phone: (253) 841-0500 Fax: (253) 840-1695 Contact: Paul Hogeboom Web site: www.pnjmachining.com **NOTE:** Scraper P/N DAD5013 is designed for removing sealant from butt joints with a 1/8 inch or larger gap. (5) Elixair Scrapers: P/N 311/03/04, 311/06/06, 311/12/04, 311/12/06, 311/24/04, 311/24/06, 311/38/04, and 311/38/06 (7.5 inch length with handle of varying widths); Skyholder Rubber Handle: P/N 310/1; Skymill Pneumatic Scraper Sharpener: P/N 309/3; Skybag for sharpener: P/N 309/3B Supplier: Elixair International Limited Address: Roman Hill Business Park, Broadmayne, Dorset DT2 8LY, United Kingdom Phone: 44 0 1305 853019 (within the UK); 44 1305 853019 (within the USA) Fax: 44 0 1305 852060 (within the UK); 44 1305 852060 (within the USA)

**Appendix A: SEALANT REMOVAL PROCEDURE FOR EXTERIOR PRESSURIZED FUSELAGE SKIN (SHEET 2 OF 8)** 
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 26, 2013 A3539 98 of 110 **BOEING SERVICE BULLETIN A3539 ALERT**  **ALERT**Contact: Len McLaughlin Web site: www.elixair.co.uk email: sales@elixair.com or lenmclaughlin@elixair.co.uk **NOTE:** 1. Scraper P/N 311/03/06 is designed for removing sealant from butt joints with a 3 mm or larger gap. 2. The pneumatic sharpener can be used to sharpen most plastic scrapers. (6) Custom Components LTD Scraper: P/N 10810 (6 inch length) Supplier: Custom Components LTD Address: Unit 3, Feltrim Business Park, Swords Co., Dublin Ireland Phone: 353 1 8901909 Fax: 353 1 8901907 (7) Bomatic, Inc. Scraper: P/N 1-6390-A (9 inch length - tapered) Supplier: Bomatic, Inc. Address: 1841 East Acacia Street, Ontario, California 91761, USA Phone: (909) 947 3900 Fax: (909) 947 5969 Contact: Kjeld Hestehave, Cathy Macri Web site: www.bomatic.com **NOTE:** Scraper P/N 1-6390-A is designed for removing sealant from butt joints with a 1/4 inch or larger gap. (8) General Tool & Supply Scraper: P/N ST982L-9ACE (9 inch length) Supplier: General Tool & Supply Address: 355 Trek Drive, Tukwila, Washington 98188, USA Phone: (206) 762-1500 Toll Free: (800) 321-3305 Fax: (206) 767-7026 Contact: Dean Zetty

**Appendix A: SEALANT REMOVAL PROCEDURE FOR EXTERIOR PRESSURIZED FUSELAGE SKIN (SHEET 3 OF 8)** 
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 26, 2013 A3539 99 of 110 **BOEING SERVICE BULLETIN A3539 ALERT**  **ALERT**Web site: www.generaltool.com email: dzetty@generaltool.com
b. Power Tools (1) 3M SR cutter - No. 3, 0.40 inch diameter, P/N 48011-30096-2 **NOTE:**Any power tool that will accept the 3M SR Cutter and has a maximum speed of 850 RPM (at the cutter) can be used. c. Solvents (1) Methyl Ethyl Ketone (MEK), ASTM D740 (2) Methyl Propyl Ketone (MPK), BMS 11-9, Grades 1 and 2 (3) Aliphatic Naptha, TT-N-95, Type I and Type III (4) Toluene, TT-T-548 or ASTM D362 (5) Isopropyl Alcohol TT-I-736 d. Miscellaneous (1) Aluminum Oxide abrasive paper, 400 grit or finer (2) Paper or wipers that meet the requirements of BSM 15-5 2. SEALANT REMOVAL NOTES: This appendix provides procedures for removing sealant from the exterior pressurized fuselage. Using these procedures will minimize the risk of damaging clad aluminum surfaces during sealant removal. The main areas of concern are: a. Lap joints b. Butt joints (including underlying splice plates) c. Other areas where sealant is present (i.e. wing to body fairings, windows, access doors, etc.) Boeing recommends only approved scrapers and tools listed in Paragraph 1 of this appendix be used for removing sealant from the exterior fuselage. Alternately, it is acceptable to use other scrapers provided they meet the requirements of BSS7384 (Method for Evaluating Tool Materials for use on Unpainted Clad Aluminum). Commonly used scraper materials such as Lexan polycarbonate, acrylic (Plexiglas), Micarta fiber reinforced phenolic resins, metal, wood, and other hard plastics have been tested and found to scratch clad aluminum.

**Appendix A: SEALANT REMOVAL PROCEDURE FOR EXTERIOR PRESSURIZED FUSELAGE SKIN (SHEET 4 OF 8)** 
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 26, 2013 A3539 100 of 110 **BOEING SERVICE BULLETIN A3539 ALERT**  **ALERT**3. SEALANT REMOVAL PROCESS: LAP JOINT FILLET a. To remove the lap joint fillet, follow this procedure: **CAUTION:** PLEASE NOTE THAT THERE IS A POTENTIAL FOR THE SR CUTTER TO "RUN AWAY" AND CAUSE DAMAGE AT THE LAP JOINT AND SURROUNDING AREA. ALSO, IF THE CUTTER CONTACTS BARE METAL BENEATH THE SEALANT, THE CLAD ALUMINUM SKIN COULD BE DAMAGED. BEFORE USING THE 3M SR CUTTER, OPERATORS SHOULD BE TRAINED ON PROPER USAGE OF THIS TOOL AND SHOULD PRACTICE ON TEST PANELS OR PIECES TO PERFECT THEIR SKILLS IN WORKING WITH THE TOOL. (1) Remove the majority of the fillet seal at the lap joint using any of the approved scrapers listed in Paragraph 1.a. of this appendix. As an alternative, the 0.4 inch diameter 3M SR Cutter listed in Paragraph 1.b. of this appendix can be used. To prevent the cutter from damaging the clad aluminum surface, do not remove the sealant to bare metal. There should be a thin layer of sealant remaining on the surface after removing the majority of the sealant with the 3M SR Cutter. (2) After removing the majority of the sealant with approved scrapers or the 3M SR Cutter, remove the remaining sealant with any of the solvents listed in Paragraph 1.c. of this appendix. An approved scraper (Paragraph 1.a.) or wiper (Paragraph 1.a.) can be used along with the solvent to help with the removal. 4. SEALANT REMOVAL: BUTT JOINTS AND OTHER AREAS WHERE SEALANT IS PRESENT ON THE EXTERIOR FUSELAGE a. To remove sealant in butt joints and other areas on the exterior fuselage, follow this procedure: **CAUTION:** THE 3M SR CUTTER IS RECOMMENDED FOR REMOVING SEALANT FROM LAP JOINTS, BUT NOT FROM BUTT JOINTS OR OTHER AREAS. (1) Remove the bulk of the sealant using any of the approved scrapers in Paragraph 1.a. of this appendix. Scrapers designed specifically for removing sealant from butt joints are available (i.e. PnJ, Elixair, Bomatic, Jus N Tyme). The shape of an approved scraper can be modified to fit a butt joint or other areas, as required. One possible modification is shown below.

**Appendix A: SEALANT REMOVAL PROCEDURE FOR EXTERIOR PRESSURIZED FUSELAGE SKIN (SHEET 5 OF 8)** 
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 26, 2013 A3539 101 of 110 **BOEING SERVICE BULLETIN A3539 ALERT**  **ALERT**(2) After removing the majority of the sealant with approved scrapers or the 3M SR Cutter, remove the remaining sealant with any of the solvents listed in Paragraph 1.c. of this appendix. An approved scraper (Paragraph 1.a.) or wiper (Paragraph 1.d.) can be used along with the solvent to help with the removal. 5. SCRAPER MAINTENANCE Scrapers dulled from use can be sharpened with 400 grit or finer aluminum oxide paper. Before using a sharpened scraper, the scraper should be rubbed on paper or cheesecloth (Paragraph 1.d.2.) to remove loose sanding particles. If an alternate method of sharpening is used, such as a metal sharpening wheel (including the Elixair International Limited pneumatic scraper sharpener), rub the scraper on 400 grit or finer aluminum oxide paper after sharpening to remove debris, and then rub the scraper on paper or cheesecloth to remove loose particles. 6. USE OF CHEMICAL STRIPPERS TO ASSIST IN SEALANT REMOVAL FOR SCRIBE LINE INSPECTION a. MATERIALS (1) Cee-Bee E-1058, McGean-Rohco, Incorporated, Atlanta Georgia. (2) Eldorado PR-5044, Eldorado Chemical Company, Incorporated, San Antonio Texas. (3) Elixair - Skyrestore (Thick), Elixair International Limited, Dorchester, England. (4) Naftosolv FN, Chemetall GMBH, Frankfurt, Germany. (5) Skycleen 2000 Aviation Cleaner, Solutia Incorporated, Saint Louis, Missouri. (6) Turco 5351, Henkel Corporation, Madison Heights, Michigan. b. SEALANT REMOVAL Use one of the following methods to remove sealant along lap and butt joints on the exterior fuselage.

**Appendix A: SEALANT REMOVAL PROCEDURE FOR EXTERIOR PRESSURIZED FUSELAGE SKIN (SHEET 6 OF 8)** 
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 26, 2013 A3539 102 of 110 **BOEING SERVICE BULLETIN A3539 ALERT**  **ALERT**(1) Method 1 - Mechanical/Chemical Remove sealant fillet with an approved scraper in accordance with Paragraph 1.a., above. Chemically strip any sealant remaining on the surface as follows: (a) Mask surrounding areas as necessary to prevent contact with chemical strippers. Do not allow chemical strippers to contact substrates other than aluminum. Do not use chemical strippers on reverse lap joints. **NOTE:** Chemical strippers will soften and remove paint. (b) Using a natural bristle brush, apply a thin coating of chemical stripper on the sealant. **CAUTION:** CHEMICAL STRIPPER MAY PENETRATE INTO JOINTS IF GAPS ARE PRESENT DUE TO MISSING FAYING SURFACE SEALANT. 1) Do not apply excessive chemical stripper. Stripper should hang and not flow. 2) Let the stripper dwell until the sealant can be easily removed by dry wiping, but do not exceed 40 minutes dwell time. 3) Remove softened sealant with clean dry wipers (BMS 15-5 Class A). Approved scrapers may be used to facilitate removal. (c) After chemical stripping is complete, remove stripper by thoroughly washing with a water-based alkaline cleaner approved for painted surfaces. Refer to SOPM 20-30-03 as an accepted procedure. Rinse off alkaline cleaner with water. (2) Method 2 - Chemical/Mechanical/Chemical (a) Mask surrounding areas as necessary to prevent contact with chemical strippers. Do not allow chemical strippers to contact substrates other than aluminum. (b) Using a natural bristle brush, apply a thin coating of chemical stripper on the sealant fillet. (c) Let the chemical stripper dwell for a maximum of 4 hours, except use a maximum dwell time of 2 hours if Turco 5351 is used. A thin coat of stripper may be brushed on every hour as necessary to maintain a wet surface. Do not apply excessive stripper. Stripper should hang and not flow. (d) Do not apply chemical stripper to areas where the joint is exposed. (e) Remove softened sealant with an approved scraper and clean dry wipers (BMS 15-5 Class A). (f) Repeat steps b., c., d., and e. if necessary, but do not apply chemical stripper to areas where the joint is exposed. (g) If any sealant remains on the surface after removing the sealant fillet, follow the procedure outlined in Method 1.

**Appendix A: SEALANT REMOVAL PROCEDURE FOR EXTERIOR PRESSURIZED FUSELAGE SKIN (SHEET 7 OF 8)** 
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 26, 2013 A3539 103 of 110 **BOEING SERVICE BULLETIN A3539 ALERT**  **ALERT**(h) After chemical stripping is complete, remove stripper by thoroughly washing with a water-based alkaline cleaner approved for painted surfaces. Refer to SOPM 20-30-03 as an accepted procedure. Rinse off alkaline cleaner with water.

**Appendix A: SEALANT REMOVAL PROCEDURE FOR EXTERIOR PRESSURIZED FUSELAGE SKIN (SHEET 8 OF 8)** 
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 26, 2013 A3539 104 of 110 **BOEING SERVICE BULLETIN A3539 ALERT**  **ALERT**Boeing recommends that operators use the format that follows to report the results of the inspections in this service bulletin to Boeing. Use of this standard format will result in a more rapid review and approval of the data. A Return to Service Proposal will be provided by Boeing after review of the data.
INTRODUCTION The following is a summary of the work carried out on airplane ___________ as part of a return to service workpack. Airplane Model: Airplane Registration: Airplane Variable Number: Airplane Line Number: Airplane Serial Number: Airplane Total Hours / Flight Cycles: Airplane Flight Cycles Since Scribe Line Introduction: BACKGROUND ____________ has completed the following work on airplane ___________: INSPECTIONS: The following inspections were completed on airplane ___________: Detailed Visual Inspections: Skin Lap Joints: Fuselage skin lap joints between STA _______ To STA _________ Findings: (Include a detailed description of any damage found, including locations, message numbers, etc. Attach additional pages as necessary.) Action:

- Skin Butt Joints: Fuselage skin butt joints between STA _______ To STA _________ Findings: (Include a detailed description of any damage found, including locations, message numbers, etc. Attach additional pages as necessary.) Action:

- External Approved Repairs: Fuselage skin around external approved repairs.

**Appendix B: REPORTING TEMPLATE - AIRPLANES WITH SCRIBE LINES (SHEET 1 OF 2)** 
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 26, 2013 A3539 105 of 110 **BOEING SERVICE BULLETIN A3539 ALERT**  **ALERT**Findings: (Include a detailed description of any damage found, including locations, message numbers, etc. Attach additional pages as necessary.) Action:

- External Features: Fuselage skin around external features. Findings: (Include a detailed description of any damage found, including locations, message numbers, etc. Attach additional pages as necessary.) Action:

- Decals and Fairings: Fuselage skin around decals and fairings. Findings: (Include a detailed description of any damage found, including locations, message numbers, etc. Attach additional pages as necessary.) Action:

- Maximum Observed Scribe Line Depth: The maximum scribe line depth for all locations (skin lap joints, skin butt joints, external approved repairs, external features, and decals and fairings) is ______ inches. Action:

- NDT Inspections: All NDT inspections for cracks at scribe line locations have been accomplished in accordance with the Accomplishment Instructions of Service Bulletin 707-A3539. Findings: (Include a detailed description of any damage found, including locations, message numbers, etc. Attach additional pages as necessary.) Action:

-

-

-

-

-

-

-

**Appendix B: REPORTING TEMPLATE - AIRPLANES WITH SCRIBE LINES (SHEET 2 OF 2)** 
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 26, 2013 A3539 106 of 110 **BOEING SERVICE BULLETIN A3539 ALERT**  **ALERT**Table 1 - Skin Lap Joints **Depth (inches)**  **Distance From Lap (Inches) Length**  **(inches) Location**  **d_aft (c) d_min**  **(b) d_fwd**  **(a) L**  **Aft Body Station**  **Forward Body Station**  **Stringer**
SSSSSS- (a) d_fwd = Distance from the edge of the upper skin of the forward end of the scribe line. (b) d_min = Minimum distance of the scribe line at any point along the entire length of the scribe line from the edge of the upper skin. (c) d_aft = Distance from the edge of the upper skin of the aft end of the scribe line.

**Appendix C: AIRPLANE FUSELAGE SCRIBE LINE MARK SUMMARY TABLES (SHEET 1 OF 2)** 
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 26, 2013 A3539 107 of 110 **BOEING SERVICE BULLETIN A3539 ALERT**  **ALERT**Table 2 - Locations other than Skin Lap Joints **Depth (inches)** **Distance From Stringer (Inch es)**  **Length (inches)**  **Stringer Aft Body**  **Station Forward Body**  **Station d_aft (b)**  **d_fwd (a) L** SSSS- (a) d_fwd = Distance of the forward end of the scribe from the stringer. (b) d_aft = Distance of the aft end of the scribe from the stringer.

**Appendix C: AIRPLANE FUSELAGE SCRIBE LINE MARK SUMMARY TABLES (SHEET 2 OF 2)** 
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 26, 2013 A3539 108 of 110 **BOEING SERVICE BULLETIN A3539 ALERT**  **ALERT**The instructions that follow can be used to make representative samples of the kinds of scribe line marks that may be found during the inspections specified in this service bulletin. This design is a visual inspection aid that can be used to familiarize visual inspectors with scribe lines and assure consistency between visual inspectors. The flag note 1 scribe line is intended to show the inspector how a scribe line can be hidden under a lap chamfer, requiring the inspector to look at an oblique angle to the lap joint edge to detect some scribes lines. The flag note 2 scribe line is intended to demonstrate a typical tactile scribe line. The flag note 3 scribe line is intended to demonstrate a shallow non-tactile scribe line. **NOTE:** Minimum surface roughness is 125 microinches. 1. 2. Break all sharp edges. 3. Unless otherwise noted, the following dimensions and tolerances are used: — All dimensions are in inches. — Tolerance on linear dimensions, other than rivet or bolt edge margins, is plus or minus 0.03 inch. — Tolerance on rivet or bolt edge margin is plus or minus 0.05 inch. — Angular tolerance is plus or minus 2 degrees. — Hole dimensions for standard solid rivets are given in 727 Structural Repair Manual, Chapter 51. 1. Make part A from bare 2024-T3 aluminum, 0.040 inch thick. 0.060 inch thick bare 2024-T3 is an acceptable substitute. 2. Make part B from bare 2024-T3 aluminum, 0.071 inch thick. 3. Fasten part B to part A with five - 5/32 inch diameter countersunk rivets. Make the countersinks in part B. 4. Make three typical scribe line marks on part A as follows: a. Flag Note 1: Scribe part A with the tip of a razor knife, using one to two pounds down load with finger pressure on the knife handle. Displaced material from the scribing operation should remain on part A. Make sure that the scribe line is under the 20 degree chamfer on the edge of part B. Make sure the scribe line can be seen visually. b. Flag Note 2: Scribe part A with the tip of a razor knife, using one to two pounds down load with finger pressure on the knife handle. Displaced material from the scribing operation should remain on part A. Make sure the scribe line is tactile (a fingernail can catch on the scribe line). c. Flag Note 3: Scribe part A with one pass from the tip of a ball point pen, using 0.25 to 0.5 pound down load. Make sure the scribe line is not tactile (a fingernail does not catch on the scribe line). As an alternative to a ball point pen, use the edge of a 0.040 inch wide CRES plate, with 0.25 inch diameter radii at the corners of the plate. This sample can be obtained from the following vendors:

**Appendix D: SCRIBE LINE SAMPLE (SHEET 1 OF 2)** 
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 26, 2013 A3539 109 of 110 **BOEING SERVICE BULLETIN A3539 ALERT**  **ALERT**NDT ENGINEERING CORP EC/NDT (Olympus NDT) 1020 South 344th St. Suite 214 421 North Quay Street Federal Way, Washington 98003 USAKennewick, Washington 99336 USA Phone: (253) 815-0797 Phone: (509) 736-2751 Fax: (253) 815-0827 Fax: (509) 735-4672

**Appendix D: SCRIBE LINE SAMPLE (SHEET 2 OF 2)** 
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 26, 2013 A3539 110 of 110 **BOEING SERVICE BULLETIN A3539 ALERT**  **ALERT**