Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 1 of 267 ALERT ALERT 

### Commercial **Airplanes** 

# 737

**ALERT ALERT**  

# Service Bulletin

**Number: 737-53A1210** Original Issue: December 14, 2000 Revision 3: July 16, 2009 ATA System: 5331 **SUBJECT:** FUSELAGE - Skin - Fuselage Skin Chem-Mill Line Crack Inspection and Repair 

## BOEING PROPRIETARY, CONFIDENTIAL, AND/OR TRADE SECRET Copyright © 2000 The Boeing Company Unpublished Work - All Rights Reserved Boeing claims copyright in each page of this document only to the extent that the page contains copyrightable subject matter. Boeing also claims copyright in this document as a compilation and/or collective work. This document includes proprietary information owned by The Boeing Company and/or one or more third parties. Treatment of the document and the information it contains is governed by contract with Boeing. For more information, contact The Boeing Company, P.O. Box 3707, Seattle, Washington 98124. Boeing, 707, 717, 727, 737, 747, 757, 767, 777, BBJ, BOEING BUSINESS JET, DC-8, DC-9, DC-10, MD-10, MD-11, MD-80, MD-90, the Boeing logo and the Boeing livery are among the trademarks owned by Boeing or its subsidiaries. No intellectual property license (express or implied) is granted in connection with this document or otherwise.**BLANK PAGE** Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 2 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT**

BLANK PAGE**Table of Contents** Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 3 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT Table of Contents**  Revision Transmittal Sheet . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 1. PLANNING INFORMATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 A. Effectivity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 1. Airplanes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 2. Spares Affected . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52 B. Concurrent Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53 C. Reason . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53 D. Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56 E. Compliance. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57 F. Approval . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65 G. Manpower . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65 H. Weight and Balance Changes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78 I. Electrical Load Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78 J. References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79 1. Existing Data: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79 2. Data supplied with this Service Bulletin: . . . . . . . . . . . . . . . . . . . . . . . . . 79 3. Installation Drawings Used in the Preparation of this Service Bulletin: . . . . . . . . . . 80 K. Publications Affected . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80 L. Interchangeability and Intermixability of Parts . . . . . . . . . . . . . . . . . . . . . . . . . 80 2. MATERIAL INFORMATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81 A. Material - Price and Availability. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81 B. Industry Support Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81 C. Parts Necessary For Each Airplane . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81 1. Kits/Parts: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81 2. Parts and Materials Supplied by the Operator: . . . . . . . . . . . . . . . . . . . . . . 81 3. Parts Modified and Reidentified: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83 4. Parts Removed and Not Replaced: . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84 D. Parts Necessary to Change Spares . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84 E. Special Tooling - Price and Availability. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84 F. Special Tooling Necessary to do this Service Bulletin . . . . . . . . . . . . . . . . . . . . . 84 3. ACCOMPLISHMENT INSTRUCTIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85 A. GENERAL INFORMATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85 B. WORK INSTRUCTIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86 FIGURE 1: THIS FIGURE WAS DELETED AT REVISION 2 . . . . . . . . . . . . . . . . . . . . . . 105 FIGURE 2: THIS FIGURE WAS DELETED AT REVISION 2 . . . . . . . . . . . . . . . . . . . . . . 106 FIGURE 3: SKIN INSPECTIONS IN THE CROWN AREA AND OTHER AREAS OF KNOWN CRACKING 107 FIGURE 4: SKIN INSPECTIONS IN THE CROWN AREA AND OTHER AREAS OF KNOWN CRACKING 112 FIGURE 5: CROWN AREA SKIN INSPECTIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . 117 FIGURE 6: CROWN AREA SKIN INSPECTIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . 120 FIGURE 7: CROWN AREA SKIN INSPECTIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . 123 FIGURE 8: THIS FIGURE WAS DELETED AT REVISION 2 . . . . . . . . . . . . . . . . . . . . . . 126 FIGURE 9: THIS FIGURE WAS DELETED AT REVISION 2 . . . . . . . . . . . . . . . . . . . . . . 127**Table of Contents** Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 4 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT** FIGURE 10: PREVENTIVE MODIFICATION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 8 FIGURE 11: SKIN INSPECTIONS IN THE LOWER LOBE AREA AND IN SECTION 41 . . . . . . . 135 FIGURE 12: SKIN INSPECTIONS IN THE LOWER LOBE AREA AND IN SECTION 41 . . . . . . . 138 FIGURE 13: SKIN INSPECTIONS IN THE LOWER LOBE AREA AND IN SECTION 41 . . . . . . . 141 FIGURE 14: SKIN INSPECTIONS IN THE LOWER LOBE AREA . . . . . . . . . . . . . . . . . . . 144 FIGURE 15: SKIN INSPECTIONS IN THE LOWER LOBE AREA . . . . . . . . . . . . . . . . . . . 147 FIGURE 16: THIS FIGURE WAS DELETED AT REVISION 2 . . . . . . . . . . . . . . . . . . . . . 150 FIGURE 17: TIME-LIMITED SKIN REPAIR AT A LAP JOINT . . . . . . . . . . . . . . . . . . . . . 151 FIGURE 18: INSPECTION OF THE TIME-LIMITED SKIN REPAIR AT A LAP JOINT. . . . . . . . . 157 FIGURE 19: THIS FIGURE WAS DELETED AT REVISION 2 . . . . . . . . . . . . . . . . . . . . . 160 FIGURE 20: THIS FIGURE WAS DELETED AT REVISION 2 . . . . . . . . . . . . . . . . . . . . . 161 FIGURE 21: SECTION 41 - EXTERNAL INSPECTION BETWEEN STA 259.5 AND STA 360 - S-19R TO 24R AND S-4L TO S-4R . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 162 FIGURE 22: SECTION 41 - EXTERNAL INSPECTION BETWEEN STA 259.5 AND STA 360 - S-24R TO S-24 L . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 164 FIGURE 23: TEAR STRAP ATTACHMENT TO SKIN INSPECTION . . . . . . . . . . . . . . . . . 166 FIGURE 24: SKIN CHEM-MILL LINE CRACK AT STRINGER 12 - REPAIR . . . . . . . . . . . . . 168 FIGURE 25: INSPECTION FOR VERTICAL CRACKS AT CHEM-MILL LINES OF FUSELAGE SKIN 175 FIGURE 26: SKIN INSPECTION - LEFT AND RIGHT HAND SIDE BETWEEN STA 360 AND STA 540, STRINGER 14 - STRINGER 26 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 179 FIGURE 27: SKIN INSPECTION - RIGHT HAND SIDE BETWEEN STA 360 AND STA 540, STRINGER 14 - STRINGER 26 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 8 FIGURE 28: SECTION 41 - SKIN INSPECTION - STRINGER-18R AND STRINGER-19R BETWEEN STA 303 AND STA 320 AND STRINGER- 15R BETWEEN STA 344 AND STA 352 . . . . 196 FIGURE 29: SKIN INSPECTIONS IN THE LOWER LOBE AREA . . . . . . . . . . . . . . . . . . . 198 FIGURE 30: TYPICAL INTERNAL INSPECTION . . . . . . . . . . . . . . . . . . . . . . . . . . . 201 FIGURE 31: SKIN INSPECTION - LEFT HAND SIDE BETWEEN STA 490 AND STA 500, STRINGER 17L 204 FIGURE 32: SKIN INSPECTION - LEFT HAND SIDE BETWEEN STA 727 AND STA 1016 . . . . . 206 FIGURE 33: SKIN INSPECTION - LEFT HAND SIDE BETWEEN STA 360 AND STA 540 AND STA 727 AND STA 1016 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 8 FIGURE 34: SKIN INSPECTION - LEFT AND RIGHT SIDE BETWEEN STA 360 AND STA 540. . . 212 FIGURE 35: SKIN INSPECTION - LEFT AND RIGHT SIDE BETWEEN STA 727 AND 1016. . . . . 218 FIGURE 36: SKIN INSPECTION - LEFT SIDE BETWEEN STA 360 AND STA 540. . . . . . . . . . 222 FIGURE 37: SKIN INSPECTION - LEFT SIDE BETWEEN STA 360 AND STA 540. . . . . . . . . . 224 FIGURE 38: TIME LIMITED REPAIR - CHEM-MILL CRACKS - NOT LOCATED AT LAP JOINTS . . 226 FIGURE 39: INSPECTION FOR VERTICAL CRACKS AT CHEM-MILL LINES OF FUSELAGE SKIN 230 FIGURE 40: INSPECTION FOR VERTICAL CRACKS AT CHEM-MILL LINES OF FUSELAGE SKIN 234 FIGURE 41: SKIN INSPECTIONS IN THE LOWER LOBE AREA . . . . . . . . . . . . . . . . . . . 238 FIGURE 42: FUSELAGE WINDOW BELT AREA INSPECTION . . . . . . . . . . . . . . . . . . . . 241 FIGURE 43: FUSELAGE WINDOW BELT AREA INSPECTION . . . . . . . . . . . . . . . . . . . . 244 FIGURE 44: FUSELAGE WINDOW BELT AREA INSPECTION . . . . . . . . . . . . . . . . . . . . 248 FIGURE 45: CROWN AREA SKIN INSPECTIONS . . . . . . . . . . . . . . . . . . . . . . . . . . 251 FIGURE 46: CROWN AREA SKIN INSPECTIONS . . . . . . . . . . . . . . . . . . . . . . . . . . 254 FIGURE 47: INSPECTION FOR VERTICAL CRACKS AT CHEM-MILL LINES OF FUSELAGE SKIN 257 FIGURE 48: POST REPAIR INSPECTION - SKIN CHEM-MILL CRACK REPAIR AT STRINGER 12 261 FIGURE 49: INSPECTION FOR VERTICAL CRACKS AT CHEM-MILL LINES OF FUSELAGE SKIN 263**Table of Contents** Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 5 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT** APPENDIX A: COST BENEFIT ANALYSIS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 67**Table of Contents** Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 6 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT**

BLANK PAGEOriginal Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 7 of 267 ALERT ALERT 

### Commercial **Airplanes** 

# 737

**ALERT ALERT**  

# Service Bulletin

**Number: 737-53A1210** 

### Revision Transmittal Sheet Original Issue: December 14, 2000 Revision 3: July 16, 2009 ATA System: 5331 **SUBJECT:** FUSELAGE - Skin - Fuselage Skin Chem-Mill Line Crack Inspection and Repair
This revision includes all pages of the service bulletin. **COMPLIANCE INFORMATION RELATED TO THIS REVISION** No more work is necessary on airplanes inspected as shown in Revision 2 of this service bulletin. More work is necessary on airplanes inspected as shown in the original issue or revision 1 of this service bulletin. Additional areas have been identified to be inspected for vertical and horizontal chem-mill line cracks. Inspection areas are clearly identified to facilitate compliance. Airplanes PM551-PM557, PM559-PM563, PW037-PW050, PW052-PW054, PW094, PW106, PW156-PW157, PW261, PW265-PW268, PW281, PW293, PW296, PW504, PW519-PW520, PW526, PW536-PW545, PW556, PW564, PW575-PW576, PW595-PW596, PW616, PW633-PW634, PW662, PW681-PW683, PW701-PW702, PW711-PW717, PW741-PW742, PW761, PW771 are added to Group 16 of this service bulletin effectivity. **REASON FOR REVISION** This revision is sent to add 737-400 airplanes to this service bulletin effectivity that were incorrectly removed in revision 2 of this service bulletin. Changes to this service bulletin include: - — Paragraph 1.A., Effectivity: Airplanes PM551-PM557, PM559-PM563, PW037-PW050, PW052-PW054, PW094, PW106, PW156-PW157, PW261, PW265-PW268, PW281, PW293, PW296, PW504, PW519- PW520, PW526, PW536-PW545, PW556, PW564, PW575-PW576, PW595-PW596, PW616, PW633- PW634, PW662, PW681-PW683, PW701-PW702, PW711-PW717, PW741-PW742, PW761, PW771 are added to the Group 16 effectivity. — Summary Compliance: FAA Airworthiness Directive is added. — Paragraph 1.E.,Compliance: FAA Airworthiness Directive is added. Compliance information and SRM reference is updated. Damage tolerance based structural inspection statement is moved to Paragraph 1.K. Publications Affected. — Paragraph 1.F., Approval: Approval information is updated. — Paragraph 1.G., Manpower: Manpower tables for Group 6, Group 7 and Group 8 is updated. — Paragraph 1.H.,Weight and Balance Changes: Weight and balance information is updated. — Paragraph 1.J., References, 1. Existing Data: FAA Airworthiness Directive is added and SRM reference is updated.Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 8 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT** — Paragraph 2.C.2. Parts and Material Supplied by the Operator: Brackets are added to the ends of fastener part numbers. — Paragraph 3.B., Work Instructions, 1 Part 1, 5 Part 5 and 6 Part 6: SRM reference is updated. — Paragraph 3.B., Work Instructions, 6 Part 6 a.,(1),(a),4),{d}: A note is added to clarify staggered fasteners locations common to the time limited repair. — FIGURE 17 and FIGURE 18: The fastener pattern has been changed to stagger fasteners common to the tear strap. — FIGURE 24: Brackets are added to the ends of fastener part numbers and SRM reference is updated. — FIGURE 35: A new inspection area is added. Paragraph 1.A., Effectivity, shows changes of airplane operators. Each operator should examine the Effectivity paragraph for changes. Vertical lines are put on the left edge of each page, except in Paragraph 1.A., Effectivity, to show the location of important changes. Pages with no vertical lines have no important changes. **REVISION HISTORY** Original Issue: December 14, 2000 Revision 1: October 25, 2001 Revision 2: March 3, 2009 Revision 3: July 16, 2009Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 9 of 267 ALERT ALERT 

### Commercial **Airplanes** 

# 737

**ALERT ALERT**  

# Service Bulletin

**Number: 737-53A1210** 

### Summary Original Issue: December 14, 2000 Revision 3: July 16, 2009 ATA System: 5331 **SUBJECT:** FUSELAGE - Skin - Fuselage Skin Chem-Mill Line Crack Inspection and Repair

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** Accomplishment of the inspections, modifications and repairs given in this service bulletin will ensure that fuselage skin cracks at chem-mill lines are found and repaired. This action is necessary to find and fix fatigue cracking of the skin panels which could result in sudden fracture and failure of the skin panels of the fuselage, and consequent rapid decompression of the airplane. Operators have reported horizontal cracks along the edges of the chem-milled pockets in the skin at S-12 in the bay forward of body station STA 520 and just above the S-4, S-10, and S-14 lap joints. Operators have reported 37 horizontal chem-mill line cracks of the fuselage crown skin at non-lap-joint areas. Skin inspection maps as given in this service bulletin present areas that need to be inspected for crown chem-mill line cracks. Fuselage skin cracks at tear strap attachments to the fuselage skin have also been reported by some operators. The chem-mill cracks were up to 8 inches long, and on at least 4 of the airplanes multiple adjacent bays were found to be cracked along the same stringer. These airplanes had flown 23,425 to 64,420 flight-cycles. Operators have reported numerous horizontal skin cracks along the edges of the chem-milled pockets in the skin below S-14, and section 41. The cracks were up to 7.25 inches long. These airplanes had flown 22,786 - 80,113 flight-cycles. Operators have also reported 13 circumferential cracks along the vertical chem-mill steps of the fuselage skin next to the STA 360, STA 727 and STA 908 Butt-Joints. The most critical situation was four in-line cracks in multiple adjacent bays on the aft side of the STA 908 butt joint from S-3R to S-7R. Crack lengths varied from 0.75 inch to 4 inches. These airplanes had flown 45,100 flight cycles (65,200 flight hours) to 67,400 flight cycles (70,800 flight hours).Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 10 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT** Analysis by Boeing indicates that these cracks are caused by fatigue due to tension stresses plus local bending stresses at the edge of chem-milled pockets or bonded skin doublers. Boeing did a cost benefit analysis on the changes given in this service bulletin. Refer to Appendix A for the analysis. Boeing Service Related Problem (SRP) 737-SRP-53-0281 is related to this service bulletin. **ACTION** On all affected airplanes, do a detailed inspection and eddy current inspection of the fuselage skin for cracks at S-12 in the bay forward of STA 520, just above the S-4, S-10, and S-14 lap joints from STA 360 to STA 1016, at S-15 between STA 360 and STA 540, aft of STA 727 and other locations of known cracking identified in this service bulletin. Skin inspection maps as given in this service bulletin indicate additional areas that need to be inspected for possible signs of chem-mill line cracks at the fuselage crown. On all affected airplanes, do a High Frequency Eddy current (HFEC) Sliding Probe inspection of the tear strap attachments to the fuselage skin for signs of cracks at the locations as given in this service bulletin. On all affected airplanes, do detailed inspection of the crown area skins from S-10L to S-10R between STA 360 and STA 1016 for indications of horizontal chem-mill line cracks. On all affected airplanes, do a detailed inspection of the lower lobe skins for cracks from S-14L to S-14R, between STA 360 and STA 1016 and in Section 41 as given in this service bulletin. Skin inspection maps as given in this service bulletin indicate additional areas that need to be inspected for possible signs of chem-mill line cracks at the fuselage lower lobe and section 41. Also, on all affected airplanes do a detailed inspection and eddy current inspections of the fuselage crown skin (from S-10L to S-10R) for vertical cracks just forward and aft of STA 360, STA 500C, STA 540, STA 727, STA 727G, and STA 908, as applicable depending on the model, along the chem-mill lines as provided in this Service Bulletin. If any crack is found, repair as given in this service bulletin, or contact Boeing for repair instructions and install the repair. **EFFECTIVITY** 737-200, -200C, -300, -400, and -500 series airplanes. Refer to Paragraph 1.A.1., Airplanes for the list of affected airplanes. **COMPLIANCE** Federal Aviation Administration (FAA) Airworthiness Directive 2004-18-06 and 98-11-04 R1 are related to this service bulletin. See Service Bulletin Paragraph 1.E. for compliance information. **INDUSTRY SUPPORT INFORMATION** Boeing warranty remedies are not available for the inspection and repair procedures given in this service bulletin. **MANPOWER** Refer to Paragraph 1.G., Manpower.Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 11 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT MATERIAL INFORMATION**  Operator Supplied Parts/Materials. Refer to Paragraph 2.A., Material - Price and Availability.

DO DETAILED INSPECTIONS OF THE LOWER LOBE SKINS BELOW S-14 FROM STA 360 TO STA 1016 AND SECTION 41 FOR CRACKS. ALSO DO DETAILED INSPECTIONS OF THE UPPER LOBE SKINS ABOVE S-10 BETWEEN STA 360 AND STA 1016. IF ANY CRACK IS FOUND, REPAIR AS GIVEN IN THIS SERVICE BULLETIN, OR CONTACT BOEING FOR REPAIR INSTRUCTIONS AND INSTALL THE REPAIR. DO DETAILED INSPECTION AND EDDY CURRENT INSPECTION FOR CRACKS JUST ABOVE S-4, S-10 AND S-14 BETWEEN STA 360 TO STA 1016 AND ALONG THE CHEM-MILL LINES AT S-12, BETWEEN STA 500D TO STA 520 FOR 737-300, STA 482B TO 520 FOR 737-500, AND STA 500E TO 520 FOR 737-400. ALSO IN THE CROWN BETWEEN S-10L AND S-10R, AND AT S-15 BETWEEN STA 360 AND STA 540 AND AFT OF STA 727. IF ANY CRACK IS FOUND, REPAIR AS GIVEN IN THIS SERVICE BULLETIN, OR CONTACT BOEING FOR REPAIR INSTRUCTIONS AND INSTALL THE REPAIR. ADDITIONAL INSPECTION MAPS ARE GIVEN IN THE SERVICE BULLETIN.

S-4L S-10L

S-14L S-15L STA 360 STA 540 STA 727 STA 908 STA 1016

STA 259.5

LEFT SIDE SHOWN RIGHT SIDE OPPOSITE 

### 737-400 SHOWN, OTHER MODELS ARE SIMILARV21666Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 12 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT**

S-10R STA 360 STA 540 STA 727 STA 908 STA 500C

STA 727G



### 737-400 SHOWN OTHER MODELS ARE SIMILAR DO EDDY CURRENT INSPECTIONS OF THE FUSELAGE SKIN FOR VERTICAL CRACKS ALONG THE CHEM-MILL LINES AT THE BUTT JOINT AND OTHER LOCATIONS GIVEN IN THIS SERVICE BULLETIN. IF ANY CRACK IS FOUND, REPAIR AS GIVEN IN THIS SERVICE BULLETIN, OR CONTACT BOEING FOR REPAIR INSTRUCTIONS AND INSTALL THE REPAIR.1522051Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 13 of 267 ALERT ALERT 

### Commercial **Airplanes** 

# 737

**ALERT ALERT**  

# Service Bulletin

**Number: 737-53A1210** Original Issue: December 14, 2000 Revision 3: July 16, 2009 ATA System: 5331 **SUBJECT:** FUSELAGE - Skin - Fuselage Skin Chem-Mill Line Crack Inspection and Repair

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 D6-19567 Part 3 for Airplane Variable Number, Line Number, and Serial Number data. This service bulletin is for the airplanes shown below.

**GROUP CONFIGURATION DESCRIPTION** 1 - 737-200C Airplanes line numbers 294 through 1113. 2 - 737-200 Airplanes line numbers 292 through 1426 with a different Section 41 solid / bonded skin configuration to Group 13. 3 - 737-300 Airplanes line numbers 1001 through 1446 with a different Section 41 solid / bonded skin configuration to Groups 6, 9, 10, 14 and 15. 4 - 737-400 Airplanes line numbers 1487 through 1922 with a different Section 41 solid / bonded skin configuration to Groups 7, 11 and 16. 5 - 737-500 Airplanes line numbers 1718 through 1921 with a different Section 41 solid / bonded skin configuration to Groups 8, 12 and 17 excluding airplane variable numbers PU001- PU007.Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 14 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT**

6 - 737-300 Airplanes line numbers 2554 through 2565 that do not require inspections for horizontal chem-mill cracks in the crown area between STA 360 and STA 1016. 7 - 737-400 Airplanes line numbers 2560 through 2564 that do not require inspections for horizontal chem-mill cracks in the crown area between STA 360 and STA 1016. 8 - 737-500 Airplane line number 2553 that does not require inspections for horizontal chem-mill cracks in the crown area between STA 360 and STA 1016. 9 - 737-300 Airplanes line numbers 1955 through 2495 with a different Section 41 solid / bonded skin configuration to Groups 3 and 14 and differences in areas in which inspections can be terminated by SB 737-53A1177. Excluding PP151-PP160 and PS751-PS756. 10 - 737-300 Airplanes line numbers 2497 through 2550 with a different Section 41 solid / bonded skin configuration to Groups 3 and 14 and differences in areas in which inspections can be terminated by SB 737-53A1177. Excluding PS757-PS762. 11 - 737-400 Airplanes line numbers 2501 through 2551 with a different Section 41 solid / bonded skin configuration to Group 4 and differences in areas in which inspections can be terminated by SB 737-53A1177. 12 - 737-500 Airplanes line numbers 2498 through 2552 with a different Section 41 solid / bonded skin configuration to Group 5 and differences in areas in which inspections can be terminated by SB 737-53A1177. 13 - 737-200 Airplanes line numbers 1453 through 1585 with a different Section 41 solid / bonded skin configuration to Group 2. 14 - 737-300 Airplanes line numbers 1447 through 1920 with a different Section 41 solid / bonded skin configuration to Groups 3, 6, 9, 10, and 15. Excluding PP127-PP148. 15 - 737-300 Airplanes line numbers 1924 through 1953 with a different Section 41 solid / bonded skin configuration to Groups 3 and 14 and differences in areas in which inspections can be terminated by SB 737-53A1177. Excluding PP149-PP150. **GROUP CONFIGURATION DESCRIPTION**Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 15 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT**

Airplane models: 737-200 737-200C 737-300 737-400 737-500 IDENTIFICATION BY CUSTOMER, CUSTOMER CODE, GROUP AND VARIABLE NUMBER A.P.S. TRADING SERV S.R.L (PSV) 2 PL019 AAM (VMA) 14 PQ192 9 PQ237 AAR AIRCRAFT SALES & LEASING (AFD) 14 PQ116 AEGEAN AIRLINES S.A. (CRM) 16 PW046 PW053 PW157 PW261 PW564 4 PW002 9 PS608 AERGO CAPITAL LIMITED (CLJ) 2 PK909 PK912 PK922 16 - 737-400 Airplanes line numbers 1931 through 2496 with a different Section 41 solid / bonded skin configuration to Group 4 and differences in areas in which inspections can be terminated by SB 737-53A1177. 17 - 737-500 Airplanes line numbers 1923 through 2494 with a different Section 41 solid / bonded skin configuration to Group 5 and differences in areas in which inspections can be terminated by SB 737-53A1177. Excluding PU008-PU025. 18 - 737-300 Airplane Variable Numbers PP149- PP160 and PS751-PS762 - Airplanes with no chem-milled skin panels in certain areas of the crown. 19 - 737-500 Airplane Variable Numbers PU001- PU007 - Airplanes with no chem-milled skin panels in certain areas of the crown. 20 - 737-500 Airplane Variable Numbers PU008- PU025 - Airplanes with no chem-milled skin panels in certain areas of the crown. 21 - 737-300 Airplane Variable Numbers PP127- PP148 - Airplanes with no chem-milled skin panels in certain areas of the crown. **GROUP CONFIGURATION DESCRIPTION**Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 16 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT** AERO CONTRACTORS OF NIGERIA (NCC) 14 PQ194 PQ196 16 PV041 17 PT396 PT401 PT420–PT421 PT430–PT431 PT433 4 PV031 AERO NORTH INTERNATIONAL (NIN) 17 PT125 AEROFLOT - CARGO (CGB) 3 PP825–PP826 AEROFLOT-DON (DAU) 17 PT507–PT508 PT701–PT703 AEROFLOT-NORD (CJS) 12 PT028 17 PT009 PT027 PT050–PT051 PT054 PT056–PT057 PT147–PT148 PT183–PT184 5 PT021–PT022 PT182 PT295 AEROGAL/GALAPAGOS AIRLINES (ERG) 14 PQ226 PQ243 2 PK715 PK827 PL102 PL110 PL171 PL624–PL625 PN030 PN405 3 PP946 AEROLINEA PRINCIPAL (APW) 2 PK775 AEROLINEAS ARGENTINAS (ARG) 12 PT304–PT306 17 PT042 PT044–PT045 PT047 PT102 PT220 PT303 PT509–PT510 2 PG584–PG585 PK102–PK103 PK735–PK737 PK740 PK747 PK750–PK751 PK755 PK757 PK761 PK765 PN104 PN110–PN115 PN117 5 PT023 PT101 PT212 PT214 AEROLINEAS AUSTRAL CHILE S.A. (LUT) 2 PK745 PL405 PM141–PM142 PN103 AEROSERVICE (SRI) 2 PL742–PL743 AEROSUCRE (SUS) 1 PY201 PY451 AEROSUR (REO) 2 PK495 PK594 PK713–PK714 PK716Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 17 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT** AEROSVIT (UKA) 14 PP924 PQ284 PQ286 16 PW039 PW265 PW268 PW595–PW596 17 PT614–PT615 2 PK564 4 PW591–PW592 AEROTECNIC, LLC (TCQ) 2 PM054 AEROVISTA GULF EXPRESS (GXP) 1 PY621 2 PK861–PK862 AIR ALGERIE (ALG) 1 PY051 PY053 2 PK633–PK634 PL722 PL724 AIR AUSTRAL (AUX) 17 PT215 AIR CANADA (ACN) 2 PK679–PK680 AIR CARRIER ACCESSORY SERVICE (RCY) 2 PN085 AIR CHINA (BEJ) 9 PQ361 PQ363–PQ364 AIR CHINA INNER MONGOLIAN (IML) 9 PQ365–PQ366 PS614–PS616 AIR CHINA SOUTHWEST BRANCH (XIN) 3 PP632–PP633 6 PQ408 9 PQ402–PQ406 AIR CHINA TIANJIN BRANCH (TJA) 9 PQ367–PQ369 AIR CORRIDOR (KRD) 2 PK468 PK749 AIR DOMINICANA (DMA) 3 PP894 AIR GUINEE (GNE) 1 PY651 AIR INDIA (IND) 1 PY631 2 PK237–PK240 PM001–PM006Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 18 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT** AIR INUIT (AIU) 1 PY243 AIR ITALY (RIT) 14 PP393 3 PP903 AIR MADAGASCAR (MAD) 14 PP852 AIR MALAWI (AML) 17 PT397 9 PS602 AIR NAMIBIA (NAM) 17 PT503–PT504 AIR NIPPON (ANK) 12 PT060 PT063 17 PT053 8 PT064 AIR NORTH YUKON'S AIRLINE (AND) 1 PY592 2 PK596 PK599 AIR ONE (ADH) 14 PQ228–PQ229 16 PV232–PV234 PV236–PV237 PW041 PW043 PW052 PW054 2 PK432 PK933 PK938 AIR PHILIPPINES (PHP) 2 PK099 PK542 PN021 PN025 PN029 PN031 PN038 PN417–PN418 AIR SLOVAKIA (SLO) 2 PK936 3 PP851 PP866 PP868–PP869 AIR TANZANIA (TNZ) 2 PN413 AIR ZIMBABWE (ZMB) 2 PN431–PN433 AIRASIA BERHAD (ASW) 14 PM385 PQ184 PQ332 3 PP002 PP021 PP407–PP409 PP471 9 PM397 AIRBALTIC CORPORATION (BCB) 17 PT005 PT161–PT163 PT424–PT425 PT428–PT429Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 19 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT** AIRCOMPANY TATARSTAN (TTQ) 17 PT170 AIRCRAFT MAINTENANCE CORP. (AMF) 2 PK254 AIRFAST INDONESIA (PTF) 2 PN481 AIRLINE CAPITAL LEASING, INC. (VTI) 2 PJ009 AIRTRAN AIRWAYS (CQT) 2 PK697 AIRWORK NZ (ANX) 1 PY741 14 PP039–PP040 PQ242 3 PP028 ALASKA AIRLINES (ASA) 11 PW241–PW242 16 PJ301–PJ302 PW231–PW240 4 PW116 7 PW245 ALOHA AIR CARGO (HLH) 1 PY131 PY463 PY593–PY594 PY721 ALTER BAIL AVIATION (ABH) 2 PK215 PK359 AMERICAN FALCON AIR (FAK) 2 PL026 AMERISTAR AIR CARGO (CGG) 2 PK221 PK560 PM051 APOLLO AVIATION GROUP LLC (APV) 3 PP234 PP419 PP421 PP905 PP981–PP982 ARIK AIR (AKD) 14 PQ154 PQ161 ASIA AIRLINES (YDO) 1 PY135 2 PL020 ASIANA AIRLINES (AAR) 7 PW283Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 20 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT** ASTRAEUS, LTD. (AUA) 9 PP929 PS605 ATLANT-SOYUZ (AYZ) 14 PP967 3 PP233 PP239 ATLANTIC AIRLINES (LNL) 2 PK673 PL008 PL622–PL623 ATLANTIC AIRLINES LTD (YDG) 14 PQ119 ATLAS BLUE (ABT) 16 PW633–PW634 17 PT581 4 PW631–PW632 AURELA (URE) 14 PQ233 9 PQ307 AURORA AVIATION (AGX) 14 PP199 PQ141–PQ142 PS666–PS667 15 PQ287 3 PP420 AUTOMATIC LLC (AUM) 2 PK759–PK760 PK764 AVE.COM (PHX) 2 PK213 PK823 PK826 PM252 3 PP892 AVIACSA AEROEXO (AEJ) 14 PP425 2 PK211 PK216–PK219 PK598 PK609 PK625–PK626 PM101–PM102 PM104–PM107 PM114–PM119 PM181 PN401–PN404 3 PP422–PP423 AVIOGENEX (AVG) 2 PN501 AVIOR (AWD) 2 PK549 PK591 PM052 PM058 PN133–PN134 PN137 PN139 PN144 PN147–PN148 PN153 PN159 AVSTAR (VSV) 2 PK355 PL111Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 21 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT** AWAS (AWW) 14 PP911–PP912 17 PT216 5 PT213 6 PQ473 BABCOCK & BROWN A/C MANAGEMENT (BBB) 3 PP848 BAHAMASAIR (BAH) 2 PL501 PL506 BASIC CAPITAL MANAGEMENT (BCM) 2 PN455 BATAVIA AIR (BTV) 11 PV203 14 PP917 PP921 16 PW156 PW575 2 PJ107 PJ112 PK252 PK283–PK284 PK305 PK360 PK514–PK515 PK563 PK617 PK622 PK635 PK711–PK712 PK825 PL413 3 PP003–PP004 PP006 PP008 PP017–PP020 PP406 4 PW005 PW015 PW020 PW032 9 PS631 BAVARIA (BAV) 14 PP984 BAYU INDONESIA AIR (BAY) 2 PK561 BCI AIRCRAFT LEASING (BLI) 1 PY112 PY134 PY462 2 PN131 PN136 PN138 PN142–PN143 3 PP231–PP232 PP237–PP238 PP679 PP682 BELAVIA (ITU) 10 PQ472 BELLVIEW AIRLINES (BEB) 2 PK203 PK612 PK872 PL028 BLUE AIR (BTR) 14 PQ160 16 PW741 3 PQ026 BLUE DART AVIATION (BDA) 13 PN521 2 PK231–PK232 PL451 PM281Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 22 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT** BLUE PANORAMA AIRLINES (BPA) 16 PW519 4 PW518 7 PW284 BLUEBIRD CARGO (BLS) 14 PM383 4 PW001 9 PQ342–PQ344 BMI BRITISH MIDLAND (BMA) 17 PT186–PT187 9 PQ292 BOA (BOV) 14 PQ304 9 PS604 BOEING CAPITAL CORPORATION (ZMF) 3 PP162 9 PQ792 BOURAQ AIRLINES (PTB) 2 PK501 PK913 PK918–PK920 PK931 BRANSON AIR (PTY) LTD (BSL) 2 PK874 PL025 BRITISH AIRWAYS (BAB) 11 PW324–PW327 14 PP841–PP842 PQ283 PQ305 16 PW301–PW302 PW305–PW308 PW312 PW314–PW315 PW317–PW323 9 PM399 BRUSSELS AIRLINES (EBA) 4 PW013 PW571–PW572 9 PS656 BULGARIA AIR (BLD) 12 PT437 14 PQ087 PQ190 PQ331 17 PT427 3 PP503 PQ086 5 PT211 9 PQ262 BURAQ AIR (BQA) 2 PL723 PL725Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 23 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT** C.I.T. LEASING CORPORATION (TCI) 14 PQ231 3 PP836 4 PW562 CANADIAN NORTH (ANP) 1 PY152–PY154 PY422 PY441 2 PK681 PL415 PN132 PN492 CAPITAL AIRCRAFT (CPT) 2 PK464 CAPITAL AIRWAYS LLC (CPY) 3 PP404 CARDIG AIR (CGD) 3 PP241–PP242 CARGO AIR (CGE) 3 PP410 CASBAH AG AVIATION DIVISION (BHV) 2 PL581 CAYMAN AIRWAYS (CAY) 1 PY244 2 PK753 9 PQ293 PQ481 CELTIC CAPITAL (IAQ) 2 PN411 CENTRALWINGS (CLW) 16 PW106 PW267 CHANCHANGI AIRLINES (CGI) 2 PL412 PL416–PL417 PN083–PN084 PN086 9 PQ362 PQ401 CHILEAN AIR FORCE (CHF) 3 PQ053 CHINA EASTERN AIRLINES (CEA) 9 PQ263 PQ411–PQ412 CHINA EASTERN AIRLINES WUHAN (WUH) 9 PQ492 CHINA POSTAL AIRLINES (YIH) 10 PQ471 9 PM407–PM409 PQ295–PQ296 PQ493Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 24 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT** CHINA SOUTHERN AIRLINES (GUN) 10 PM542 PQ407 PQ479–PQ480 12 PT061–PT062 14 PQ252–PQ255 6 PM543–PM544 PM547 9 PM412 PM541 CHINA UNITED AIRLINES (CUL) 14 PP728–PP729 9 PS609–PS610 CHINA XINHUA AIRLINES (XIH) 10 PQ804–PQ805 6 PM546 9 PQ264 CHINA XINJIANG AIRLINES (XIJ) 6 PM545 CIRRUS ME S.A.L (CMU) 2 PM103 CITYLINE HUNGARY LTD. (CTZ) 1 PY101 COMAIR LIMITED (CML) 14 PP915 PP923 16 PW118 PW215–PW216 PW303 PW310–PW311 PW556 2 PK734 PK738 PK744 PK748 PK754 PK758 3 PQ001 PQ003–PQ006 PQ008 PQ010 4 PW111–PW112 PW115 CONOCOPHILLIPS ALASKA, INC. (ATR) 2 PN452–PN453 CONTINENTAL AIRLINES (CAL) 14 PP721–PP726 PP730 PP732–PP733 3 PP671–PP675 PP678 PP680–PP681 PP683 PP688–PP699 PP701 PP703–PP710 PP712–PP720 CONVIASA S.A. (VSS) 14 PP198 PQ117 PS668 2 PL005 PL010 PN154–PN155 CORENDON AIRLINES (HVA) 16 PM557 7 PW282Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 25 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT** CSA (CSA) 16 PW304 PW309 17 PT617–PT621 4 PW517 CSC TRANSPORT (CTC) 4 PW007 DAIMLERCHRYSLER AVIATION (DCY) 3 PP119–PP120 DBA (DBA) 9 PP511 PP515 PS655 DELMUN AVIATION SERVICES (DLM) 2 PK318 DELTA AIR LINES (DAL) 2 PN149 PN161 PN415 3 PP240 PP243 DELTA CONNECTION (DTC) 1 PY272 DNIPROAVIA (DNE) 14 PP510 17 PT041 4 PW031 DOLPHIN AIR (FDN) 1 PY241 2 PL151 DONGHAI AIRLINES (JWC) 3 PP651–PP652 9 PM396 PM405 EASTOK AVIA (ETK) 13 PN493 14 PP034 PP440 2 PK632 PN407–PN408 PN410 PN416 4 PV023 PW011 EDREES AVIATION (SME) 2 PL505 EG&G TECHNICAL SERVICES (EGN) 2 PJ205 PJ207–PJ210 PL763 EGYPTAIR (EGP) 17 PT561 PT563–PT565Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 26 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT** ESEN AIR LTD. (ESN) 2 PK317 PL729 ESTAFETA (EST) 1 PY275 14 PQ224–PQ225 3 PP833 PP846 ESTELAR (ESQ) 13 PL626 EUROPE AIRPOST (EUE) 14 PP392 PP951–PP952 PS641–PS642 15 PP925 3 PP832 PP947 9 PQ421 PQ771 PS607 PS643–PS644 EUROPEAN AVIATION AIR CHARTER (EUL) 1 PY273 2 PK041 PK044 PK046 PK048–PK049 PN001 3 PP965 EUROPEAN CAPITAL HOLDINGS (ECC) 2 PJ006 PK524–PK525 PK641–PK642 EXECUTIVE JET AIRCRAFT COMPANY (EXF) 2 PL441 EXPORT RESTRICTED AIRPLANES (YWV) 1 PY022 PY141–PY142 2 PJ003 PK214 PK391 PL758 9 PQ288–PQ289 EXPRESSAIR (PTX) 2 PK304 PM022 FAA (FAA) 2 PL768 FEDERATIVE REPUBLIC OF BRAZIL (BRZ) 2 PK068–PK069 FIRST AIR (BRS) 1 PY133 PY281 PY410 PY421 2 PK358 PL407 FLAIR AIRLINES (FLR) 16 PW662 4 PW503 FLANA (FLQ) 1 PY270Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 27 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT** FLYING CARPET (FYC) 2 PM064 PN140 FLYLAL CHARTERS (LCT) 14 PQ189 FRESH AIR LTD. (FRR) 2 PN024 PN035 FUTURA (FUA) 14 PP430 PP432 16 PW047–PW048 PW101 PW266 3 PP899 4 PV032 PW561 GA TELESIS, LLC (GTG) 2 PK233 PK235 PK739 GARUDA INDONESIA (GIA) 10 PQ487 11 PW461–PW467 14 PP508 PQ285 16 PV271 PW067 PW119 PW712 9 PM404 PP514 PS653 GARY AIRCRAFT (GRH) 2 PL745 GE AVIATION MATERIALS (GML) 3 PP001 GECAS (GEF) 14 PP840 2 PK026–PK027 PK256 PK466–PK467 3 PP235–PP236 4 PW009 PW012 PW018–PW019 PW021 9 PM398 PM410–PM411 GENERIC CUSTOMER/SUPPLIER (XXX) 1 PY411 PY611 14 PP046 PP431 PP436–PP438 PP936 15 PQ199 17 PT382–PT383 PT385 2 PH743 PJ005 PJ110–PJ111 PK029 PK112 PK144 PK253 PK274 PK286 PK503 PK519 PK801 PK803–PK804 PK821 PK934 PL004 PL009 PL012 PL014–PL016 PL023 PL107 PL112 PL740–PL741 PL793 PM253 3 PP031 PP161Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 28 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT** GEORGIAN AIRWAYS (GEI) 14 PP044 17 PT611 5 PT181 GERMANIA (GER) 14 PP507 PP838 PQ152 PQ234–PQ235 3 PP961 9 PQ230 GLOBAL AIR (YCH) 2 PJ004 PK145 PK548 PK595 PL013 GOL AIRLINES (GOT) 14 PP922 PQ120 PQ143–PQ145 PQ158 PQ162–PQ163 PQ191 PQ193 PQ195 PQ227 PQ303 15 PP988 9 PP989–PP990 HAINAN AIRLINES (HNA) 14 PQ088–PQ091 PQ156–PQ157 4 PW093 9 PS611 PS613 HAMBURG INTERNATIONAL (HAU) 3 PP904 HOLA AIRLINES (HLB) 4 PW006 IAI (IAI) 2 PK692 ICARO (IKA) 1 PY461 2 PK742 PK771 IDM CAS (IDN) 2 PK552 ILFC (ILF) 14 PQ302 17 PT169 9 PQ491 INDIAN AIR FORCE (IDF) 2 PM016–PM017 INTAL AIR (IRT) 1 PY242 PY274 2 PK312Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 29 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT** INTERAIR (ITI) 1 PY046–PY047 2 PK546 PK610 PL108 PL113 INTERLINK AIRLINES (ILK) 2 PK743 PK904 PK907 PL103 IRAQI AIRWAYS (IRQ) 14 PQ198 JANCO AIRCRAFT AND ENGINES (JNC) 2 PM282–PM283 JAPAN TRANSOCEAN AIR (SWL) 16 PW520 PW681–PW683 4 PW515–PW516 JAT YUGOSLAV AIRLINES (JAT) 14 PP778–PP779 PQ241 3 PP771–PP777 4 PV024 JATAYU AIR (JAJ) 2 PJ117 PK257 PK511 JET LITE (JPQ) 16 PW064 PW066 9 PQ306 JET MIDWEST (JMI) 2 PK558 PM057 PM060 PM066 JET TIME (JME) 14 PM384 PM391 3 PP504 PP897 JET2.COM LTD (CEX) 14 PP908–PP909 PP913–PP914 PQ038–PQ039 3 PQ027 PQ030–PQ037 PQ051–PQ052 PQ054–PQ055 PQ058–PQ059 JET4YOU.COM (JFU) 4 PW511 PW661 JETAIRFLY (TLB) 17 PT103 JETCONNECT LIMITED (JCL) 14 PQ013–PQ016 16 PW540 PW542–PW543 3 PQ012Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 30 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT** JETLEASE (JLI) 1 PY595 JETRAN INTERNATIONAL, LTD. (JTI) 2 PK593 JETSCAPE LEASING (IAN) 4 PW008 JETSTAR PACIFIC AIRLINES (PAH) 16 PW102 PW316 JORDAN AVIATION (JOR) 14 PQ123–PQ124 PQ187 17 PT671 3 PP896 4 PW502 JSC "AIRCOMPANY SCAT" (DVW) 17 PT426 PT435 JSC STARLINE.KZ (MZK) 2 PK911 PL556 KARTHAGO AIRLINES (KAG) 14 PQ180 9 PP926 PP928 PP930 KARTIKA AIRLINES (KRK) 2 PK309–PK310 KD AVIA (JSK) 14 PP196 PP426 PP429 PP837 PP843–PP844 PP916 PQ232 3 PP016 PP305 PP383 PP418 PP424 PP475 PP801 PP867 PP870 9 PS652 KLM - ROYAL DUTCH AIRLINES (KLM) 14 PP871–PP873 16 PW616–PW619 3 PP861 PP863–PP864 4 PW014 PW017 PW611–PW615 9 PP874–PP875 LAC (CQC) 1 PY113 LAM (LAM) 2 PL455–PL456 PN451 PN454Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 31 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT** LAN AIRLINES (LAN) 2 PK431 PK914 LAPA ARGENTINA (LAZ) 2 PK051 LAS VEGAS SANDS, CORP. (LVS) 14 PP506 PQ236 LIBYAN AIRLINES (LAA) 2 PK361 LINEAS AEREAS AZTECA (AZX) 14 PP983 PP986 LION AIR (MLI) 16 PW037–PW038 PW042 3 PP181–PP182 4 PW016 PW022–PW023 PW025 PW029 PW501 LJH AVIATION MANAGEMENT (WAT) 2 PL006 LLC GLOBUS (LLG) 16 PW526 LOBAYE AIRWAYS (LBY) 2 PN409 LOCALEASE (LLA) 2 PK282 LOCKHEED MARTIN (LMA) 3 PQ057 LOT POLISH AIRLINES (LOT) 11 PV283 16 PV281–PV282 PW065 17 PT651–PT655 LUFTHANSA GERMAN AIRLINES (DLH) 14 PQ062–PQ073 PQ092 17 PT331–PT360 3 PQ060–PQ061 9 PQ074–PQ085 PS701–PS703 LUXAIR (LUX) 17 PT672 MACEDONIAN AIRLINES, MACEDONIA (MCC) 17 PT612–PT613Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 32 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT** MACQUARIE AIR FINANCE (ZGT) 16 PW504 3 PP022 PP962 MAGELLAN AIRCRAFT SERVICES (MAP) 14 PQ113 MAGNICHARTERS (MAM) 14 PQ168 2 PK143 PL454 PL554 PL558 3 PP405 PQ028 MALAYSIA AIRLINES (MAS) 11 PJ551 PW224–PW230 16 PW044 PW201–PW214 PW217–PW223 7 PJ552 MANDALA AIRLINES (MND) 2 PK255 PK636 PL027 PL421 PL744 PN002 4 PW004 PW010 MANGAL AIRLINES (MGG) 2 PL785 MARANATHA LEASING CORPORATION (MNT) 2 PK201–PK202 PL011 MAX AVIA (MXY) 2 PK222 PK315 PK671 PK830 PL732 MERPATI NUSANTARA AIRLINES (PNM) 14 PP043 PP434–PP435 PQ281 2 PK354 PK614–PK615 PK623–PK624 PK819 PK917 PK929–PK930 PL409 3 PP898 4 PW091 MEXICO'S PRESIDENTIAL AIRCRAFT (MXG) 14 PP919 PQ155 MIDAMERICAN AEROSPACE, LTD (MML) 1 PY231 2 PL557 MIRAGE AVIATION LTD (MLE) 3 PP991 MISTRAL AIR (MSX) 14 PQ222 9 PQ341 PS638Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 33 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT** MNG AIRLINES (MHK) 4 PW512 PW514 PW593 NAT AVIATION U.S.A. (NTV) 2 PK258 PK551 PK557 PK732 NATIONAL CITY (NTJ) 2 PL471 NATIONWIDE AIRLINES (NWR) 2 PJ007–PJ008 PK357 PK741 PK871 PK906 PK928 PK932 PL631–PL632 PN107 PN109 NEW AXIS AIRWAYS (NXA) 14 PQ301 4 PW033 NEWJET (NES) 2 PL172 PL562 NICON AIRWAYS LTD. (EAV) 2 PL453 PN032 NOK AIR (OWL) 16 PM553 PW045 NOLINOR AVIATION (NLO) 1 PY671–PY672 NORDESTE (NDT) 14 PP987 NORTHERN AIR CARGO (NAC) 2 PN150–PN152 NORTHSTAR PRESIDIO MANAGEMENT (INH) 2 PK094–PK095 NORWEGIAN AIR SHUTTLE AS (NSB) 14 PM381 PM389 PP805–PP808 PP918 PP985 9 PM401–PM402 PQ791 PQ793 PS601 PS654 NOVA AIR (PDM) 2 PL007 PL406 PN412 PN414 OKAY AIRWAYS COMPANY LIMITED (OKY) 3 PP631 PP634 9 PQ290Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 34 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT** OLYMPIC AIRLINES (OLY) 16 PV201–PV202 PV231 PW068 PW072 PW711 PW713–PW717 PW771 4 PW063 9 PS657 OLYMPIC AIRWAY SERVICES (OLS) 4 PW062 ONE SOURCE AEROSPACE (OSA) 2 PK043 ORENBURG AIRLINES (ORG) 17 PT010 PT301–PT302 4 PW028 PW036 ORIX AVIATION SYSTEMS (OXA) 5 PT121 OUR AIRLINE (NAU) 3 PP831 PP902 OZJET AIRLINES (OZJ) 2 PK045 PK050 PK052–PK053 PACE AIRLINES (PIE) 2 PL001 PL502–PL503 PN102 PN116 3 PP835 PACIFIC PEARL AIRWAYS (PPA) 2 PN146 PACIFIC SKY AVIATION INC. (SEF) 17 PT219 PAKISTAN INT'L AIRLINES (PIA) 3 PP281–PP286 9 PS612 PAMIR AIRWAYS (PMY) 2 PN135 PEGASUS AIRLINES (PGS) 4 PW030 PERUVIAN AIR FORCE (PRF) 2 PN082 PERUVIAN AIR LINE S.A. (PVU) 2 PK802 PHILIPPINE AIRLINES (PAL) 9 PQ803Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 35 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT** PHUKET AIRLINES (PHK) 2 PN037 PN039 PLATINUM AIRWAYS (PLW) 14 PP189 PLUNA (PLU) 2 PL201–PL203 PRECISIONAIR (PCR) 15 PM395 PT. INDONESIA AIRASIA (WAA) 14 PM388 PM390 9 PP516–PP517 PT. TOP AIR (PTZ) 13 PK528 2 PK937 Q AVIATION (QAV) 14 PQ132 2 PK288 PK603–PK604 QANTAS (QAN) 11 PW546 PW557 16 PW536–PW539 PW541 PW544–PW545 3 PQ002 PQ007 PQ009 PQ011 4 PW531–PW535 QUIKJET (QKJ) 14 PQ221 PQ223 REGIONALCARGO (RGC) 1 PY057 REPEX AIRLINES (REX) 1 PY102–PY103 REPUBLIC OF INDONESIA (IDO) 2 PL601–PL603 REPUBLIC OF KOREA AIR FORCE (KAF) 3 PP221 REPUBLIC OF NIGER (NIR) 1 PY166 REPUBLIC OF VENEZUELA (VNZ) 2 PK070 REPUBLICAIR (RPB) 2 PL553 PL555Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 36 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT** RICO (RLA) 2 PK120 ROSSIYA RUSSIAN AIRLINES (STG) 17 PT164–PT168 ROYAL AIR MAROC (RAM) 17 PT582–PT584 2 PK271–PK272 ROYAL KHMER AIRLINES (KHM) 2 PN163 RUTACA AIRLINES (ZRU) 2 PK281 PK611 PK613 PK901 PK903 PK915–PK916 PM062 RUTAS AEREAS VENEZOLANAS S.A. (RTV) 2 PK822 PL402 PL414 PN145 PN157 RYAN INTERNATIONAL AIRLINES (RYN) 14 PQ197 2 PK543 PK606 RYM AIRLINES (RYM) 2 PL017–PL018 S7 AIRLINES (SBR) 16 PM556 PW094 17 PT381 PT388–PT389 PT501–PT502 PT505–PT506 4 PW051 SAFAIR (SFA) 2 PK731 PK746 PK824 PK974 PL061 SAFAIR OPERATIONS (SFZ) 2 PK820 SAFI AIRWAYS (FFI) 3 PP521–PP522 SAMA AIRLINES (AWM) 14 PP509 15 PM393–PM394 9 PS606 PS651 SAS NORWAY (BRT) 16 PW574 PW576 17 PT002–PT004 PT006–PT008 PT011 PT024–PT025 4 PW573Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 37 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT** SAT AIRLINES (SKH) 2 PL221 PN158 SAUDI ARABIAN AIRLINES (SVA) 1 PY036 2 PK316 PL727–PL728 PL730–PL731 PL733 SEAGLE AIR (SGQ) 3 PP964 SHAHEEN INTERNATIONAL (SHK) 2 PK602 PK608 PL003 PL551 PL561 PN036 SHANTOU AIRLINES (SHT) 9 PM415–PM417 SHENZHEN AIRLINES (SHZ) 9 PQ486 PS691–PS692 SIERRA PACIFIC AIRLINES (SRP) 2 PK627 PL621 SILVER AIR (SARL) (SVT) 14 PP935 2 PK313–PK314 PL726 PL734 3 PP865 SILVER SKY (SLZ) 2 PN419 SKY AIRLINES (SYC) 11 PW278 16 PV235 PW281 PW293 PW296 SKY EXPRESS (SXR) 17 PT058 PT124 PT217–PT218 PT616 3 PQ056 5 PT123 PT146 9 PQ258–PQ259 SKY HOLDING COMPANY (PSH) 2 PK752 PL401 PL403 PN491 3 PP802 SKY KING (SKN) 2 PK351–PK353 PK696 PL002 PN156 PN162Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 38 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT** SKY SERVICE (SSV) 2 PK526–PK527 PK628–PK629 PK772 PK881 PK884 PK902 PK908 PK910 PK923 PK927 PK971 PK973 PL736 SKYEUROPE (SKP) 12 PT438 17 PT434 SKYNET ASIA AIRWAYS (SNU) 16 PM555 4 PW026 SLOK AIR (SRO) 2 PM108–PM113 SOUTH AFRICAN AIRWAYS (SAA) 2 PL104–PL106 9 PM413–PM414 SOUTHERN WINDS (SOW) 2 PK047 PK616 SOUTHWEST AIRLINES (SWA) 14 PP169 PP188 PP190–PP193 PP205 PP353 PP727 PP731 18 PP149–PP160 PS751–PS762 19 PU001–PU007 2 PM065 20 PU008–PU025 21 PP127–PP148 3 PP101–PP118 PP121–PP126 PP163–PP168 PP202–PP204 PP301–PP304 PP351 PP376–PP380 PP382 PP402–PP403 PP501–PP502 PP803–PP804 PP821–PP824 PP827 SPACE WORLD AIRLINE/SWA (WIN) 2 PL021–PL022 SRIWIJAYA AIR (SJA) 14 PP910 2 PJ114 PK302–PK303 PK307–PK308 PK777 PM021 PM254 PN023 PN026–PN027 PN040 PN042–PN043 4 PW034–PW035 PW061 9 PP927 STA SUPPLIES PTE. LTD. (SSP) 14 PQ040–PQ041 STAR (EQA) 13 PN512Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 39 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT** STAR AIR (SGY) 2 PN033 STAR UP S.A. (SRU) 2 PJ115 PK921 PL611 STEWART INDUSTRIES INT'L (SDT) 13 PN473 2 PK905 PK926 PK935 PM251 SUNDOWNER OKLAHOMA CITY LLC (SDO) 16 PW313 SWIFT AIR (SWF) 14 PM392 3 PP352 PP847 PP862 PP948 SWIFT AIR LLC (SFW) 16 PV042–PV043 4 PW563 TAAG (ANGOLA AIRLINES) (ANG) 1 PY162 2 PK661 PK664–PK666 TACA INTERNATIONAL AIRLINES (TAC) 2 PL737 PN420 TAF LINHAS AEREAS (TFL) 2 PL404 PN160 TAILWIND AIRLINES (TWK) 11 PW243–PW244 TAROM - ROMANIAN AIR TRANSPORT (TRM) 10 PQ931–PQ932 TEEBAH AIRLINES (EBH) 2 PK601 PK605 PN028 THAI AIRASIA (THA) 3 PP411–PP412 PP676–PP677 PP684 PP686–PP687 THAI AIRWAYS INTERNATIONAL (TII) 16 PW164–PW167 4 PW161–PW162 PW594 THE MOURITZEN FAMILY TRUST (MRZ) 1 PY191 THE PEGASUS AVIATION COMPANY (PEG) 2 PK285Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 40 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT** TITAN AIRWAYS (TIU) 14 PM387 PP505 9 PS636–PS637 TNT AIRWAYS (TNB) 14 PP391 PP433 PP845 3 PP384 PP413–PP414 PP472 PP474 PP702 PP711 TRAFIC (TFI) 1 PY056 TRANS AIR CONGO (TSC) 2 PK562 PK763 TRANSAERO AIRLINES (TRX) 14 PP966 16 PW040 PW120 17 PT046 PT049 PT052 PT104–PT105 2 PK451 PK773 PK779 3 PP963 4 PW024 PW113–PW114 TRANSMILE AIR SERVICES (TML) 1 PY151 13 PN474 2 PN472 TRAVEL SERVICE (TSF) 12 PT436 17 PT432 TRIGANA AIR (TGN) 2 PL504 TRITON AVIATION SERVICES (TIA) 2 PK677 PL408 PL410–PL411 PL770 PN101 PN105–PN106 PN108 TUIFLY (HAP) 4 PW513 TUNISAIR (TUN) 17 PT641–PT642 TURKISH AIRLINES (THY) 16 PM552 PM559–PM560 PM562–PM564 PW049–PW050 TURKMENISTAN AIRLINES (TUE) 9 PQ265 PQ801–PQ802 UETAAM (MXA) 2 PN041Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 41 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT** UKRAINE INTERNATIONAL AIRLINES (UKR) 14 PM382 PQ251 16 PM551 PM554 PM561 PW701–PW702 PW742 17 PT043 PT048 PT055 PT059 PT511–PT512 UNITED AIR LINES (UAL) 14 PQ111–PQ112 PQ114–PQ115 PQ118 PQ121–PQ122 PQ125–PQ131 PQ133–PQ140 PQ146–PQ151 PQ164–PQ167 PQ169–PQ179 PQ181–PQ183 PQ185–PQ186 15 PQ201–PQ202 17 PT384 PT386–PT387 PT390–PT395 PT398–PT399 PT402–PT419 PT422–PT423 3 PQ101–PQ110 UNIVERSAL ASSET MANAGEMENT (UAM) 2 PM056 PM059 PM061 UNKNOWN CUSTOMER (UNZ) 17 PT185 2 PK111 PK114 PK118–PK119 PK675 US AIR FORCE (USF) 2 PJ202 PJ206 PJ211 PJ213–PJ219 US AIRWAYS (USA) 14 PP032 PP036–PP038 PP047–PP054 PP185–PP187 PP194–PP195 PP197 PP428 PP439 16 PV044–PV055 2 PL081 PL560 3 PP005 PP007 PP014–PP015 PP024–PP027 PP029–PP030 PP183–PP184 PP401 PP417 PP834 PP891 PP893 PP895 PP901 PP931–PP934 4 PV001–PV010 PV012–PV022 PV025–PV030 PV033–PV040 9 PS669 UT FINANCE CORPORATION (ZZJ) 14 PQ153 VASP AIRLINES (VSP) 2 PK581 9 PP512 VIKING AIRLINES (VAI) 9 PQ291 VISION AIR (VIL) 2 PK863 3 PP685Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 42 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT** VIVA AEROBUS (VIV) 14 PP041 PP427 3 PP009–PP010 PP013 PP023 PP473 VOLVO AERO SERVICES (AGD) 3 PP381 WEBJET LINHAS AEREAS LTDA. (WJL) 14 PP839 PP906–PP907 PQ159 PQ188 15 PQ256–PQ257 9 PQ260–PQ261 PQ266–PQ267 PS603 WELLS FARGO (FSB) 9 PP513 WEST DOVER LLC (WDR) 3 PP415 WESTAIR CARGO AIRLINES (WCO) 1 PY037 WESTSTAR AVIATION (WSE) 2 PK565 WILMINGTON TRUST COMPANY (WBT) 14 PP035 PP042 PP045 WINGS OF LEBANON S.A.L. (WGL) 2 PN141 XSTRATA CANADA CORPORATION (NAD) 1 PY612 XTRA AIRWAYS (CIN) 16 PW761 4 PW117 ZAMBIAN AIRWAYS (MBA) 2 PK220 PL109 ZASA (CZA) 2 PL735 IDENTIFICATION BY VARIABLE NUMBER **Variable Group** PG584–PG586 2 PH001 2 PH011–PH013 2 PH021–PH024 2 PH743 2Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 43 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT**

PJ003–PJ009 2 PJ105–PJ119 2 PJ201–PJ219 2 PJ301–PJ302 16 PJ551 11 PJ552 7 PK026–PK029 2 PK041–PK053 2 PK061–PK070 2 PK081–PK082 2 PK091–PK099 2 PK101–PK103 2 PK111–PK120 2 PK141–PK146 2 PK201–PK204 2 PK211–PK223 2 PK231–PK241 2 PK251–PK258 2 PK271–PK274 2 PK281–PK289 2 PK291 2 PK301–PK318 2 PK341 2 PK351–PK361 2 PK391 2 PK431–PK433 2 PK451–PK452 2 PK461–PK469 2 PK495 2 PK501–PK504 2 PK511–PK515 2 PK519 2 PK521–PK527 2 PK528 13 PK541–PK565 2 PK581 2 PK591–PK599 2 PK601–PK617 2 PK621–PK637 2 **Variable Group**Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 44 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT**

PK641–PK642 2 PK661–PK666 2 PK671–PK681 2 PK691–PK697 2 PK711–PK716 2 PK731–PK765 2 PK771–PK779 2 PK801–PK804 2 PK819–PK827 2 PK830 2 PK861–PK863 2 PK871–PK874 2 PK881–PK884 2 PK901–PK938 2 PK971–PK974 2 PL001–PL028 2 PL061 2 PL081 2 PL101–PL113 2 PL151 2 PL171–PL172 2 PL201–PL203 2 PL221 2 PL401–PL417 2 PL421 2 PL441 2 PL451–PL456 2 PL471 2 PL491 2 PL501–PL506 2 PL551–PL562 2 PL581 2 PL601–PL603 2 PL611 2 PL621–PL625 2 PL626 13 PL631–PL632 2 PL717–PL746 2 PL747 13 **Variable Group**Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 45 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT**

PL756 2 PL758 2 PL761–PL770 2 PL781–PL788 2 PL793 2 PM001–PM006 2 PM016–PM017 2 PM021–PM023 2 PM051–PM066 2 PM101–PM119 2 PM141–PM142 2 PM171 2 PM181 2 PM251–PM255 2 PM281–PM283 2 PM381–PM392 14 PM393–PM395 15 PM396–PM399 9 PM401–PM417 9 PM541 9 PM542 10 PM543–PM547 6 PM551–PM564 16 PN001–PN002 2 PN021–PN043 2 PN081–PN086 2 PN101–PN117 2 PN131–PN163 2 PN401–PN420 2 PN431–PN433 2 PN451–PN456 2 PN471–PN472 2 PN473–PN474 13 PN481 2 PN491–PN492 2 PN493 13 PN501 2 PN502 13 PN511–PN512 13 **Variable Group**Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 46 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT**

PN521 13 PP001–PP031 3 PP032–PP054 14 PP101–PP126 3 PP127–PP148 21 PP149–PP160 18 PP161–PP168 3 PP169 14 PP181–PP184 3 PP185–PP199 14 PP201–PP204 3 PP205 14 PP221 3 PP231–PP243 3 PP281–PP286 3 PP301–PP305 3 PP351–PP352 3 PP353 14 PP376–PP384 3 PP391–PP393 14 PP401–PP424 3 PP425–PP440 14 PP471–PP475 3 PP501–PP504 3 PP505–PP510 14 PP511–PP517 9 PP521–PP522 3 PP631–PP634 3 PP651–PP652 3 PP671–PP699 3 PP701–PP720 3 PP721–PP733 14 PP771–PP777 3 PP778–PP779 14 PP801–PP804 3 PP805–PP808 14 PP821–PP827 3 PP831–PP836 3 PP837–PP845 14 **Variable Group**Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 47 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT**

PP846–PP848 3 PP851 3 PP852 14 PP861–PP870 3 PP871–PP873 14 PP874–PP875 9 PP891–PP899 3 PP901–PP905 3 PP906–PP924 14 PP925 15 PP926–PP930 9 PP931–PP934 3 PP935–PP936 14 PP946–PP948 3 PP951–PP952 14 PP961–PP965 3 PP966–PP967 14 PP981–PP982 3 PP983–PP987 14 PP988 15 PP989–PP990 9 PP991 3 PP993 14 PQ001–PQ012 3 PQ013–PQ016 14 PQ026–PQ037 3 PQ038–PQ041 14 PQ051–PQ061 3 PQ062–PQ073 14 PQ074–PQ085 9 PQ086 3 PQ087–PQ092 14 PQ101–PQ110 3 PQ111–PQ198 14 PQ199 15 PQ201–PQ202 15 PQ221–PQ229 14 PQ230 9 PQ231–PQ236 14 **Variable Group**Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 48 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT**

PQ237 9 PQ241–PQ243 14 PQ251–PQ255 14 PQ256–PQ257 15 PQ258–PQ267 9 PQ281–PQ286 14 PQ287 15 PQ288–PQ296 9 PQ301–PQ305 14 PQ306–PQ307 9 PQ331–PQ332 14 PQ341–PQ344 9 PQ361–PQ369 9 PQ401–PQ406 9 PQ407 10 PQ408 6 PQ411–PQ413 9 PQ421 9 PQ471–PQ472 10 PQ473 6 PQ479–PQ480 10 PQ481 9 PQ486 9 PQ487 10 PQ491–PQ493 9 PQ771 9 PQ791–PQ793 9 PQ801–PQ803 9 PQ804–PQ805 10 PQ931–PQ932 10 PS601–PS616 9 PS631 9 PS636–PS638 9 PS641–PS642 14 PS643–PS644 9 PS651–PS657 9 PS666–PS668 14 PS669 9 PS691–PS692 9 **Variable Group**Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 49 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT**

PS701–PS703 9 PS751–PS762 18 PT001–PT011 17 PT021–PT023 5 PT024–PT027 17 PT028 12 PT041–PT059 17 PT060–PT063 12 PT064 8 PT101 5 PT102–PT105 17 PT121–PT123 5 PT124–PT125 17 PT146 5 PT147–PT148 17 PT161–PT170 17 PT181–PT182 5 PT183–PT187 17 PT211–PT214 5 PT215–PT220 17 PT295 5 PT301–PT303 17 PT304–PT306 12 PT331–PT360 17 PT381–PT399 17 PT401–PT435 17 PT436–PT438 12 PT501–PT512 17 PT561–PT565 17 PT581–PT584 17 PT611–PT621 17 PT641–PT642 17 PT651–PT655 17 PT671–PT672 17 PT701–PT703 17 PU001–PU007 19 PU008–PU025 20 PV001–PV040 4 PV041–PV055 16 **Variable Group**Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 50 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT**

PV201–PV202 16 PV203 11 PV231–PV237 16 PV271–PV272 16 PV281–PV282 16 PV283 11 PW001–PW036 4 PW037–PW050 16 PW051 4 PW052–PW054 16 PW061–PW063 4 PW064–PW068 16 PW072 16 PW091–PW093 4 PW094 16 PW101–PW102 16 PW106 16 PW111–PW117 4 PW118–PW120 16 PW156–PW157 16 PW161–PW162 4 PW163–PW167 16 PW201–PW223 16 PW224–PW230 11 PW231–PW240 16 PW241–PW244 11 PW245 7 PW261 16 PW265–PW268 16 PW278 11 PW281 16 PW282–PW284 7 PW293 16 PW296 16 PW301–PW323 16 PW324–PW327 11 PW461–PW467 11 PW501–PW503 4 PW504 16 **Variable Group**Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 51 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT**

PW511–PW518 4 PW519–PW520 16 PW526 16 PW531–PW535 4 PW536–PW545 16 PW546 11 PW556 16 PW557 11 PW561–PW563 4 PW564 16 PW571–PW573 4 PW574–PW576 16 PW591–PW594 4 PW595–PW596 16 PW611–PW615 4 PW616–PW620 16 PW631–PW632 4 PW633–PW634 16 PW661 4 PW662 16 PW681–PW683 16 PW701–PW702 16 PW711–PW717 16 PW741–PW742 16 PW761 16 PW771 16 PY022 1 PY036–PY037 1 PY046–PY048 1 PY051–PY053 1 PY056–PY057 1 PY101–PY103 1 PY111–PY113 1 PY131–PY135 1 PY141–PY143 1 PY151–PY154 1 PY156–PY157 1 PY161–PY162 1 PY166 1 **Variable Group**Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 52 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT**

2. Spares Affected
None. PY191 1 PY201 1 PY221–PY222 1 PY231 1 PY241–PY244 1 PY270–PY275 1 PY281 1 PY286 1 PY401 1 PY409–PY411 1 PY421–PY422 1 PY441 1 PY451 1 PY461–PY463 1 PY591–PY595 1 PY611–PY612 1 PY621 1 PY631 1 PY651 1 PY671–PY672 1 PY721 1 PY741 1 **Variable Group**Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 53 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT B. Concurrent Requirements** 
None **C. Reason** Accomplishment of the inspections, modifications and repairs given in this service bulletin will ensure that fuselage skin cracks at chem-mill lines are found and repaired. This action is necessary to find and fix fatigue cracking of the skin panels which could result in sudden fracture and failure of the skin panels of the fuselage, and consequent rapid decompression of the airplane. Operators have reported horizontal cracks along the edges of the chem-milled pockets in the skin at S-12 in the bay forward of body station STA 520 and just above the S-4, S-10, and S-14 lap joints. Operators have reported 37 horizontal chem-mill line cracks of the fuselage crown skin at non-lap-joint areas. Skin inspection maps as given in this service bulletin present areas that need to be inspected for crown chem-mill line cracks. Fuselage skin cracks at tear strap attachments to the fuselage skin have also been reported by some operators. The chem-mill cracks were up to 8 inches long, and on at least 4 of the airplanes multiple adjacent bays were found to be cracked along the same stringer. These airplanes had flown 23,425 to 64,420 flight-cycles. Operators have reported numerous horizontal skin cracks along the edges of the chem-milled pockets in the skin below S-14, and section 41. The cracks were up to 7.25 inches long. These airplanes had flown 22,786 - 80,113 flight-cycles. Operators have also reported 13 circumferential cracks along the vertical chem-mill steps of the fuselage skin next to the STA 360, STA 727 and STA 908 Butt-Joints. The most critical situation wasfour in-line cracks in multiple adjacent bays on the aft side of the STA 908 butt joint from S-3R to S7R. Crack lengths varied from 0.75 inch to 4 inches. These airplanes had flown 45,100 flight cycles (65,200 flight hours) to 67,400 flight cycles (70,800 flight hours). Analysis by Boeing indicates that these cracks are caused by fatigue due to tension stresses plus local bending stresses at the edge of chem-milled pockets or bonded skin doublers. Boeing did a cost benefit analysis on the changes given in this service bulletin. Refer to Appendix A for the analysis. Boeing Service Related Problem (SRP) 737-SRP-53-0281 is related to this service bulletin.
Revision 1 was sent to: — Clarify in the Summary, Reason and Description sections that cracks were reported at stringer 12. — Move S-12 data from the second table to the first table in the Reason section. — Add the Preventive Modification to the Manpower table. — Add Cost Benefit Analysis and Weight and Balance information. — Add SRM 53-30-03; NDT 53-30-09; SIIA 737-242 and installation drawings to the Reference section. — Revise the Figures referenced in Parts and Materials Supplied by Operator and added the material required to perform the Preventive Modification. — Delete the Group 7 inspection requirements from the Part 1 Work Instructions. — Add reference to AMM for fairing removal in Part 3 Lower Lobe Area Skin Inspection. — Add Part 6 Preventive Modification requirements for Groups 3, 5, 6, and 8 to the Work Instructions. — Add Preventive Modification to Figure 1 and changed the reference of Fig. 3-10 to Fig. 3-9. — Add the reference of 737-300 to Figure 5, 737-400 to Figures 6 and 14, and 737-500 to Figures 7 and 15.Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 54 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT**

— Delete the inspection requirements at S-4 and S-10 locations in Figure 8 on Group 6 airplanes. — Delete the original Figure 9, which was the inspection of group 7 airplanes. — Revise the old Figure 10 to the new Figure 9 and deleted the inspection of S-4 and S-10 locations. — Add the Figure 10 Preventive Modification. — Revise 53-00-00 to 51-00-00 in Figure 16 notes c, e, f, g and Figure 20 notes a, c, and d.Boeing did a cost benefit analysis on the changes given in this service bulletin. Refer to Appendix A for the analysis. Revision 2 was sent to tell operators of modified inspection thresholds, modified inspection intervals, new inspection areas and to remove inspections from areas that have solid skins. Also additional NDT inspection methods have been added. Changes in Revision 2 of this service bulletin include: - — Subject: The title is changed to include "chem-mill line crack". — Background and Reason: Have been updated to include new data. — Action and Description: Have been updated to include new inspection locations and inspection methods. — Effectivity: Have been split into new groups. — Compliance Section: Updated the Compliance information. — Approval: Have been updated to include AD requirements. — Manpower: Have been updated to include new inspection areas. — Weight and Balance: Have been updated to remove Figure 16 and Figure 20 skin repairs. — References: Have been updated. — Work instructions: Have been updated to included new inspection areas, remove and add new skin repairs. — FIGURE 1 and FIGURE 2: Logic diagrams have been deleted. — FIGURE 3, FIGURE 4, FIGURE 5, FIGURE 6, FIGURE 7 and FIGURE 10: Have been updated to add new inspections. — FIGURE 8, FIGURE 9, FIGURE 16, FIGURE 19 and FIGURE 20: Have been deleted. — FIGURE 11, FIGURE 12, FIGURE 13, FIGURE 14 and FIGURE 15: Have been updated to remove inspection areas. — FIGURE 21 AND FIGURE 22: Adds NDT inspections between STA 259.5 and STA 360. — FIGURE 23: Adds NDT inspection of the tear straps. — FIGURE 24: Adds a skin repair for chem-mill line cracks at stringer 12. — FIGURE 25: Adds a vertical crack inspections at STA 312, STA 360, STA 460, STA 500C, STA 540, STA 727, STA 727G and STA 908. — FIGURE 26: Adds a skin inspection on the left side between STA 360 and STA 540. — FIGURE 27: Adds a skin inspection on the right side between STA 360 and STA 540. — FIGURE 28: Adds a skin inspection on the right side between STA 303 and STA 320 and between STA 344 and STA 352. — FIGURE 29: Adds skin inspections to the lower lobe area. — FIGURE 30: Adds a typical internal skin inspection. — FIGURE 31: Adds a skin inspection on the left side between STA 490 and STA 500. — FIGURE 32: Adds a skin inspection on the left side between STA 727 and STA 1016. — FIGURE 33: Adds a skin inspection on the left side between STA 360 and STA 540 and between STA 727 and STA 1016. — FIGURE 34: Adds skin inspections on the left and right side between STA 360 and STA 540. — FIGURE 35: Adds skin inspections on the left and right side between STA 727 and STA 1016. — FIGURE 36 and FIGURE 37: Adds a skin inspection on the left side between STA 360 and STA 540. — FIGURE 38: Adds a time limited skin repair for chem-mill cracks not located at lap joints.Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 55 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT**

— FIGURE 39: Adds a vertical crack inspections at STA 312, STA 360, STA 460, STA 500C, STA 540, STA 727 and STA 908. — FIGURE 40: Adds a vertical crack inspections at STA 312, STA 360, STA 460, STA 540, STA 727 and STA 908. — FIGURE 41: Provides skin inspections for the lower lobe area. — FIGURES 42, 43 and 44: Provide window belt inspections previously in Figures 5, 6 and 7 respectively. — FIGURE 45: Provides crown area skin inspections for Groups 18 and 21. — FIGURE 46: Provides crown area skin inspections for Groups 19 and 20. — FIGURE 47: Provides inspection for vertical cracks at chem-mill lines of fuselage skin for Groups 18 through 21. — FIGURE 48: Provides post repair inspection for the skin chem-mill crack repair at stringer 12. — FIGURE 49: Adds a vertical crack inspections at STA 312, STA 360, STA 460, STA 500C, STA 540, STA 727 and STA 908. Revision 3 is sent to add 737-400 airplanes to this service bulletin effectivity that were incorrectly removed in revision 2 of this service bulletin. Changes in Revision 3 of this service bulletin include: - — Paragraph 1.A., Effectivity: Airplanes PM551-PM557, PM559-PM563, PW037-PW050, PW052- PW054, PW094, PW106, PW156-PW157, PW261, PW265-PW268, PW281, PW293, PW296, PW504, PW519-PW520, PW526, PW536-PW545, PW556, PW564, PW575-PW576, PW595- PW596, PW616, PW633-PW634, PW662, PW681-PW683, PW701-PW702, PW711-PW717, PW741-PW742, PW761, PW771 are added to the Group 16 effectivity. — Summary Compliance: FAA Airworthiness Directive is added. — Paragraph 1.E.,Compliance: FAA Airworthiness Directive is added. Compliance information and SRM reference is updated. Damage tolerance based structural inspection statement is moved to Paragraph 1.K. Publications Affected. — Paragraph 1.F., Approval: Approval information is updated. — Paragraph 1.G., Manpower: Manpower tables for Group 6, Group 7 and Group 8 is updated. — Paragraph 1.H.,Weight and Balance Changes: Weight and balance information is updated. — Paragraph 1.J., References, 1. Existing Data: FAA Airworthiness Directive is added and SRM reference is updated. — Paragraph 2.C.2. Parts and Material Supplied by the Operator: Brackets are added to the ends of fastener part numbers. — Paragraph 3.B., Work Instructions, 1 Part 1, 5 Part 5 and 6 Part 6: SRM reference is updated. — Paragraph 3.B., Work Instructions, 6 Part 6 a.,(1),(a),4),{d}: A note is added to clarify staggered fasteners locations common to the time limited repair. — FIGURE 17 and FIGURE 18: The fastener pattern has been changed to stagger fasteners common to the tear strap. — FIGURE 24: Brackets are added to the ends of fastener part numbers and SRM reference is updated. — FIGURE 35: A new inspection area is added.Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 56 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT D. Description**  On all affected airplanes, do a detailed inspection and eddy current inspection of the fuselage skin for cracks at S-12 in the bay forward of STA 520, just above the S-4, S-10, and S-14 lap joints from STA 360 to STA 1016, at S-15 between STA 360 and STA 540, aft of STA 727 and other locations of known cracking identified in this service bulletin. Skin inspection maps as given in this service bulletin indicate additional areas that need to be inspected for possible signs of chem-mill line cracks at the fuselage crown. On all affected airplanes, do a High Frequency Eddy current (HFEC) Sliding Probe inspection of the tear strap attachments to the fuselage skin for signs of cracks at the locations as given in this service bulletin. On all affected airplanes, do detailed inspection of the crown area skins from S-10L to S-10R between STA 360 and STA 1016 for indications of horizontal chem-mill line cracks. On all affected airplanes, do a detailed inspection of the lower lobe skins for cracks from S-14L to S-14R, between STA 360 and STA 1016 and in Section 41 as given in this service bulletin. Skin inspection maps as given in this service bulletin indicate additional areas that need to be inspected for possible signs of chem-mill line cracks at the fuselage lower lobe and section 41. Also, on all affected airplanes do a detailed inspection and eddy current inspections of the fuselage crown skin (from S-10L to S-10R) for vertical cracks just forward and aft of STA 360, STA 500C, STA 540, STA 727, STA 727G, and STA 908, as applicable depending on the model, along the chem-mill lines as provided in this Service Bulletin. If any crack is found, repair as given in this service bulletin, or contact Boeing for repair instructions and install the repair. Revision 2 - More work is necessary on airplanes inspected as given in revision 1, or original issue of this service bulletin. Additional areas have been identified to be inspected for vertical and horizontal chem-mill line cracks. Inspection areas are clearly identified to facilitate compliance. Revision 3 - No more work is necessary on airplanes inspected as shown in Revision 2 of this service bulletin.Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 57 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT E. Compliance**  Federal Aviation Administration (FAA) Airworthiness Directives 2004-18-06 and 98-11-04 R1 are related to this service bulletin. Accomplishment of Boeing service bulletin (SB) 737-53A1177 Revision 2, 3, 4, 5 or 6 terminates inspections under the repair area only. On all airplanes: Accomplishment of SB 737-53A1177 does not terminate inspection requirements above S-10 lap joints on the left and right side from STA 540 to STA 727. Group 1-5, 9-21: Table 1 - Skin Inspection Requirements - Fuselage Crown Area And Other Areas Of Known Cracks - Horizontal Chem-Mill Line and Skin Cracks at the Tear Strap Tabs
**Condition Action Compliance Time**  **(Whichever Occurs Later) Repeat Interval**  **(Not to Exceed)** Areas previously inspected as given in the original issue or revision 1 of this service bulletin. Do external detailed inspection and eddy current inspection for any crack as given in Accomplishment Instruction 3.B.1. Part 1 - Crown Area Skin Inspection.(c) (f) Within 4,500 flight cycles from the accomplishment of the last inspection as given in the original issue or revision 1 of this service bulletin. 4,500 Flight Cycles.(a)(b)

Areas that have not been inspected as given in the original issue or revision 1 of this service bulletin. Do external detailed inspection and eddy current inspection for any crack as given in Accomplishment Instruction 3.B.1. Part 1 - Crown Area Skin Inspection.(c) (f) Before 35,000 total airplane flight cycles. 4,500 Flight Cycles.(b)

Any crack found in the fuselage skin. Do the repair as given in Accomplishment Instruction 3.B.5. Part 5 - Permanent Repair. (d) (e) or Do the repair as given in Accomplishment Instruction 3.B.6. Part 6 - Time Limited Repair.(d) Before further flight. -

Time Limited Repair is installed and is located at lap splice. Do an external detailed inspection of the repaired area for any cracks and loose, missing or damaged fasteners as given in Accomplishment Instruction 3.B.6.a.(1).(a).3). Within 3,000 flight cycles from the time the repair was installed. 3,000 flight cycles. (e)Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 58 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT**

Time Limited Repair is installed and is not located at lap splice. Do an external detailed inspection of the repaired area for any cracks and loose, missing or damaged fasteners as given in Accomplishment Instruction 3.B.6.a.(2).(c). Within 3,000 flight cycles from the time the repair was installed. 3,000 flight cycles. (e)

Damaged or loose fasteners found. Replace any damaged or loose fasteners. Before further flight. -
Crack found at a Time Limited Repair. Contact Boeing for repair instructions and install the repair. Before further flight. -

Time Limited Repair is installed and is located at lap splice. Install permanent repair as given in Accomplishment Instruction 3.B.6.a.(1).(a).4). (g) Within 6,000 flight cycles from the time the repair was installed. Within 1,000 flight cycles from the date of revision 3 of this service bulletin. -

Time Limited Repair is installed and is not located at lap splice. Install permanent repair as given in Accomplishment Instruction 3.B.6.a.(2).(d). (g) Within 6,000 flight cycles from the time the repair was installed. Within 1,000 flight cycles from the date of revision 3 of this service bulletin. -

(a) Areas that have been inspected according to the previous releases of this service bulletin need to have repeat inspections according to the requirements of this table. (b) For non lap splice areas between STA 360 to STA 1016 and S-10L to S-10R it is optional to do general visual inspections at 1,000 flight cycle intervals in lieu of the detailed inspections. (c) It is not required to inspect the chem-mill steps under existing external repair doublers provided either: 1. The installed repair was approved by the FAA or by a Boeing company authorized representative who was authorized by the FAA to make such findings, and the installed repair extends a minimum of three rows of fasteners on each side of the chem-mill line, Or 2. The doubler extends a minimum of 2 rows beyond the chem-mill step and was accomplished in accordance with Figure 42 or 48 of 737-100/200 SRM 53-30-3, or Repair 30 or 31 of 737-300 SRM 53-00-01, 737-400 SRM 53-00-01 or 737-500 SRM 53-00-01. Inspections are not required directly under the repair doubler. Do the inspections required in areas adjacent to the doubler. If the repair does not meet the above conditions, then inspect the chem-mill step internally in the area covered by the doubler as given in 737 NDT, Part 6, 53-30-20. (d) If the repair given in Accomplishment Instructions, PART 5 or PART 6 are not applicable, contact Boeing for repair instructions and install repair before further flight. Group 1-5, 9-21: Table 1 - Skin Inspection Requirements - Fuselage Crown Area And Other Areas Of Known Cracks - Horizontal Chem-Mill Line and Skin Cracks at the Tear Strap Tabs
**Condition Action Compliance Time**  **(Whichever Occurs Later) Repeat Interval**  **(Not to Exceed)**Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 59 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT**

(e) Accomplishment of the Part 5 - Permanent Repair is terminating action for repeat inspections under the repair area only. (f) It is not required to inspect the skin at the tear strap tabs under existing external repair doublers provided either: 1. The installed repair was approved by the FAA or by a Boeing company authorized representative who was authorized by the FAA to make such findings, and the installed repair extends a minimum of three rows of fasteners above and below tear strap tab fasteners that require inspection, Or 2. The doubler extends a minimum of 2 rows above and below the tear strap tab fasteners that require inspection, and the repair was accomplished in accordance with Figure 48 of 737-100/200 SRM 53-30-3, or Repair 31 of 737-300 SRM 53-00-01, 737-400 SRM 53-00-01 or 737-500 SRM 53-00-01. Inspections are not required directly under the repair doubler. Do the inspections required in areas adjacent to the doubler. If the repair does not meet the above conditions, then inspect the skin under the repair doubler at tear strap tab using LFEC as given in 737 NDT, Part 6, 53-30-00 Figure 5. (g) Accomplishment of the permanent repair is terminating action for repeat inspections under the repair area only. Group 3, 9-10, 14-15, 18, 21: Table 2 - Skin Inspection Requirements - Fuselage Window Belt Area Between STA 500D to STA 520 and Stringer S-10 to S-14 - Horizontal Chem-Mill Line Cracks
**Condition Action Compliance Time**  **(Whichever Occurs Later) Repeat Interval**  **(Not to Exceed)** Areas previously inspected as given in the original issue or revision 1 of this service bulletin. Do external detailed inspection and eddy current inspection as given in Accomplishment Instruction 3.B.2.a. (a) (c) Within 4,500 flight cycles from the accomplishment of the last inspection given in the original issue or revision 1 of this service bulletin. 4,500 Flight Cycles.

Areas that have not been inspected as given in the original issue or revision 1 of this service bulletin. Do external detailed inspection and eddy current inspection as given in Accomplishment Instruction 3.B.2.a. (a) (c) Before 25,000 total airplane flight cycles. Within 4,500 flight cycles from the date of revision 3 of this service bulletin 4,500 Flight Cycles.

Any crack found in the fuselage skin. Do the repair as given in Accomplishment Instruction 3.B.8. Part 8 - Skin Chem-Mill Line Crack At Stringer 12 - Repair Instructions. (b) (c) Before further flight. - Group 1-5, 9-21: Table 1 - Skin Inspection Requirements - Fuselage Crown Area And Other Areas Of Known Cracks - Horizontal Chem-Mill Line and Skin Cracks at the Tear Strap Tabs
**Condition Action Compliance Time**  **(Whichever Occurs Later) Repeat Interval**  **(Not to Exceed)**Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 60 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT**

(a) It is not required to inspect areas under existing external repair doublers provided the installed repair was approved by the FAA or by a Boeing company authorized representative who was authorized by the FAA to make such findings, and the installed repair extends a minimum of three rows of fasteners on each side of the chem-mill line. 1. If the repair does not meet the above conditions, then inspect the chem-mill step internally in the area covered by the doubler as given in 737 NDT, Part 6, 53-30-20. (b) If the repair given in Accomplishment Instructions, PART 8 is not applicable, contact Boeing for repair instructions and install repair before further flight.(c) Accomplishment of the preventive modification as given in Part 7 or the repair as given in Part 8 terminates the inspection requirements for the chem-mill steps common to stringer 12 only. All other chem-mill inspections in this area must continue. Group 4, 11, 16: Table 3 - Skin Inspection Requirements - Fuselage Window Belt Area Between STA 500E to STA 500F and STA 500G to STA 520 and Stringer S-10 to S-14 - Horizontal Chem-Mill Line Cracks
**Condition Action Compliance Time**  **(Whichever Occurs Later) Repeat Interval**  **(Not to Exceed)** All Airplanes Do external detailed inspection and eddy current inspection as given in Accomplishment Instruction 3.B.2.b. (a) Before 25,000 total airplane flight cycles. Within 4,500 flight cycles from the date of revision 3 of this service bulletin 4,500 Flight Cycles.

Any crack found in the fuselage skin. Contact Boeing for repair instructions and install repair. Before further flight. -

(a) It is not required to inspect areas under existing external repair doublers provided he installed repair was approved by the FAA or by a Boeing company authorized representative who was authorized by the FAA to make such findings, and the installed repair extends a minimum of three rows of fasteners on each side of the chem-mill line. 1. If the repair does not meet the above conditions, then inspect the chem-mill step internally in the area covered by the doubler as given in 737 NDT, Part 6, 53-30-20. Group 3, 9-10, 14-15, 18, 21: Table 2 - Skin Inspection Requirements - Fuselage Window Belt Area Between STA 500D to STA 520 and Stringer S-10 to S-14 - Horizontal Chem-Mill Line Cracks
**Condition Action Compliance Time**  **(Whichever Occurs Later) Repeat Interval**  **(Not to Exceed)**Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 61 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT** Group 5, 12, 17, 19-20: Table 4 - Skin Inspection Requirements - Fuselage Window Belt Area Between STA 482B to STA 520 and Stringer S-10 to S-14 - Horizontal Chem-Mill Line Cracks
**Condition Action Compliance Time**  **(Whichever Occurs Later) Repeat Interval**  **(Not to Exceed)** Areas previously inspected as given in the original issue or revision 1 of this service bulletin. Do external detailed inspection and eddy current inspection as given in Accomplishment Instruction 3.B.2.c. (a) Within 4,500 flight cycles from the accomplishment of the last inspection given in the original issue or revision 1 of this service bulletin. 4,500 Flight Cycles.

Areas that have not been inspected as given in the original issue or revision 1 of this service bulletin. Do external detailed inspection and eddy current inspection as given in Accomplishment Instruction 3.B.2.c (a) Before 25,000 total airplane flight cycles. Within 4,500 flight cycles from the date of revision 3 of this service bulletin. 4,500 Flight Cycles.

Any crack found in the fuselage skin. Do the repair as given in Accomplishment Instruction 3.B.8. Part 8 - Skin Chem-Mill Line Crack At Stringer 12 - Repair Instructions. (b) (c) Before further flight. -

(a) It is not required to inspect areas under existing external repair doublers provided the installed repair was approved by the FAA or by a Boeing company authorized representative who was authorized by the FAA to make such findings, and the installed repair extends a minimum of three rows of fasteners on each side of the chem-mill line. 1. If the repair does not meet the above conditions, then inspect the chem-mill step internally in the area covered by the doubler as given in 737 NDT, Part 6, 53-30-20. (b) If the repair given in Accomplishment Instructions, PART 8 is not applicable, contact Boeing for repair instructions and install repair before further flight. (c) Accomplishment of Part 8 repair terminates the inspection requirements for the chem-mill steps common to the stringer 12 only. All other chem-mill inspections in this area must continue.Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 62 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT** Group 1-5, 9-21: Table 5 - Skin Inspection Requirements - Vertical Chem-Mill Line Cracks - Fuselage Butt Joints in the Crown Area And Other Areas Of Known Cracks
**Condition Action Compliance Time**  **(Whichever Occurs Later) Repeat Interval**  **(Not to Exceed)** All airplanes. Do external detailed inspection and eddy current inspection for any crack as given in Accomplishment Instruction 3.B.3. Part 3 Vertical Crack Inspection. (a) Before 55,000 total airplane flight cycles or 55,000 total airplane flight hours whichever occurs first. Within 4,500 flight cycles or 4,500 flight hours whichever occurs first from the date of revision 3 of this service bulletin. 4,500 Flight Cycles or 4,500 flight hours whichever occurs first.

Any crack found in the fuselage skin. Do the repair as given in as given in Accomplishment Instruction 3.B.5.Part 5 - Permanent Repair. (b) (c) Before further flight. -

(a) It is not required to inspect areas under existing external repair doublers provided either: 1. The installed repair was approved by the FAA or by a Boeing company authorized representative who was authorized by the FAA to make such findings, and the installed repair extends a minimum of three rows of fasteners on each side of the chem-mill line Or 2. The doubler extends a minimum of 2 rows beyond the chem-mill step and was accomplished in accordance with 737-100/200 SRM 53-30-3 Figure 48, or Repair 31 of 737-300 SRM 53-00-01, 737-400 SRM 53-00-01 or 737-500 SRM 53-00-01. Do the inspections required in areas adjacent to the doubler. If the repair does not meet the above conditions, then inspect the chem-mill step internally in the area covered by the doubler as given in 737 NDT, Part 6, 53-30-20. (b) If the repairs given in Accomplishment Instructions, PART 5 are not applicable, contact Boeing for repair instructions and install repair before further flight. (c) Accomplishment of the Part 5 - Permanent Repair is terminating action for repeat inspections under the repair area only.Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 63 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT** Group 1-21: Table 6 - Skin Inspection Requirements - Fuselage Lower Lobe Area and Section 41 - Horizontal Chem-Mill Line Cracks
**Condition Action Compliance Time**  **(Whichever Occurs Later) Repeat Interval**  **(Not to Exceed)** Areas that require detailed inspections as given in this service bulletin. Do external detailed inspection for any crack as given in Accomplishment Instruction 3.B.4. Part 4 - Lower Lobe Area and section 41 Skin Inspection. (b) Before 35,000 total airplane flight cycles. Within 4,500 flight cycles from the date of revision 3 of this service bulletin, or Within 9,000 flight cycles from the accomplishment of the detailed inspections given in the original issue or revision 1 of this Service Bulletin. 4,500 Flight Cycles. (a) (e)

Areas that require detailed and eddy current inspections as given in this service bulletin. Do external detailed inspection and eddy current inspection for any crack as given in Accomplishment Instruction 3.B.4. Part 4 - Lower Lobe Area and section 41 Skin Inspection. (b) Before 35,000 total airplane flight cycles. Within 4,500 flight cycles from the date of revision 3 of this service bulletin. 4,500 Flight Cycles. (e)

Any crack found in the fuselage skin. Do the repair as given in Accomplishment Instruction 3.B.5. Part 5 - Permanent Repair. (c) (d) or Do the repair as given in Accomplishment Instruction 3.B.6. Part 6 - Time-Limited Repair.(c) Before further flight. - -

Time Limited Repair is installed and is located at lap splice. Do an external detailed inspection of the repaired area for any cracks and loose, missing or damaged fasteners as given in Accomplishment Instruction 3.B.6.a.(1).(a).3). Within 3,000 flight cycles from the time the repair was installed. 3,000 flight cycles. (d)

Time Limited Repair is installed and is not located at lap splice. Do an external detailed inspection of the repaired area for any cracks and loose, missing or damaged fasteners as given in Accomplishment Instruction 3.B.6.a.(2).(c). Within 3,000 flight cycles from the time the repair was installed. 3,000 flight cycles. (d)

Damaged or loose fasteners found. Replace any damaged or loose fasteners. Before further flight. -Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 64 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT**

Crack found at a Time Limited Repair. Contact Boeing for repair instructions and install the repair. Before further flight. -

Time Limited Repair is installed and is located at lap splice. Install permanent repair as given in Accomplishment Instruction 3.B.6.a.(1).(a).4). (f) Within 6,000 flight cycles from the time the repair was installed. Within 1,000 flight cycles from the date of revision 3 of this service bulletin. -

Time Limited Repair is installed and is not located at lap splice. Install permanent repair as given in Accomplishment Instruction 3.B.6.a.(2).(d). (f) Within 6,000 flight cycles from the time the repair was installed. Within 1,000 flight cycles from the date of revision 3 of this service bulletin. -

(a) Areas that have been inspected according to the previous releases of this service bulletin need to have repeat inspections according to the requirements of this table. (b) It is not required to inspect areas under existing external repair doublers provided either: 1. The installed repair was approved by the FAA or by a Boeing company authorized representative who was authorized by the FAA to make such findings, and the installed repair extends a minimum of three rows of fasteners on each side of the chem-mill, Or 2. The doubler extends a minimum of 2 rows beyond the chem-mill step and was accomplished in accordance with Figure 42 or 48 of 737-100/200 SRM 53-30-3, or Repair 30 or 31 of 737-300 SRM 53-00-01, 737-400 SRM 53-00-01 or 737-500 SRM 53-00-01. Inspections are not required directly under the repair doubler. Do the inspections required in areas adjacent to the repair doubler. If the repair does not meet the above conditions, then inspect the chem-mill step internally in the area covered by the doubler as given in 737 NDT, Part 6, 53-30-20. (c) If the repair given in Accomplishment Instructions, PART 5 or PART 6 are not applicable, contact Boeing for repair instructions and install repair before further flight. (d) Accomplishment of the Part 5 - Permanent Repair is terminating action for repeat inspections under the repair area only. (e) It is optional to do general visual inspections at 1,000 flight cycle intervals in lieu of the detailed inspections. (f) Accomplishment of the permanent repair is terminating action for repeat inspections under the repair area only. Group 3, 5, 9-10, 12, 14-15, 17-21: Table 7 - Post Repair Inspection - Skin Chem-mill Line Crack at Stringer 12 Repair **Condition Action Compliance Time Repeat Interval** Repair Installed as given in Figure 24 Do external LFEC inspections of the skin at the critical row of fasteners in the repair as given in Accomplishment Instructions 3.B.8.b. Within 43,000 Flight Cycles from the installation of the repair. 3,500 Flight Cycles Group 1-21: Table 6 - Skin Inspection Requirements - Fuselage Lower Lobe Area and Section 41 - Horizontal Chem-Mill Line Cracks
**Condition Action Compliance Time**  **(Whichever Occurs Later) Repeat Interval**  **(Not to Exceed)**Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 65 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT F. Approval**  This service bulletin was examined by the Federal Aviation Administration (FAA). The changes specified in this service bulletin comply with the applicable regulations and are FAA approved, as well as European Aviation Safety Agency (EASA)/Joint Aviation Authorities (JAA) approved for all EASA/ JAA approved airplanes listed in the service bulletin effectivity. This service bulletin and its approval were based on the airplane in its original Boeing delivery configuration or as modified by other approved Boeing changes. If an airplane has a non-Boeing modification or repair that affects a component or system also affected by this service bulletin, the operator is responsible for obtaining appropriate regulatory agency approval before incorporating this service bulletin. For airplanes identified in the service bulletin, Revision 3, the repair and/or modification of this service bulletin, Revision 3, have been reviewed as required by paragraph (g) of Airworthiness Directive (AD) 98-11-04 R1. Those repairs in this service bulletin that contain directed inspection satisfy the requirement of AD 98-11-04 R1, paragraph (g). All permanent repairs called out in this service bulletin are installed per the SRM. These contain the guidance necessary to determine if it affects an SSI or creates a new SSI and also contains the necessary inspection. However, any repair that results from the inspection findings of this service bulletin, should be assessed with respect to the requirements of AD 98-11-04 R1, paragraph (g), to determine if it affects or creates a SSI. This service bulletin has been approved by the FAA. In addition, the Manager of the FAA Seattle Aircraft Certification Office approves the inspections, repairs, and modifications defined in this service bulletin as an alternative method of compliance to the requirements of paragraph (a), (b), (c), (d), (e), (f), (g), and (i) of AD 2004-18-06. All provisions of 2004-18-06 that are not specifically referenced in the above statement remain fully applicable and must be complied with. Skin panels replaced according to the instructions of SB 737-53-1168, SB 737-53-1187 or SB 737-53- 1273 are approved as an Alternative Method of Compliance (AMOC) to the Airworthiness Directive 2004-18-06 paragraphs (a), (b), (c), (d) and (e) in the areas of replaced skin panel only. All provisions of AD 2004-18-06 that are not specifically referenced in the above statement remain fully applicable and must be complied with. **G. Manpower** The table below shows an estimate of the man-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 man-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 partsOriginal Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 66 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT**

— Time to find the tools. Group 1:
**Task Number of**  **Persons Task Hours Elapsed Hours** Open Access 1 1.00 1.00 Figure 3 6 131.00 23.50 Figure 11 4 53.00 13.25 Figure 17 - (a) (a) Figure 18 - (b) (b) Figure 23 4 55.00 13.75 Figure 28 1 2.00 2.00 Figure 30 - (c) (c) Figure 32 1 2.00 2.00 Figure 38 - (a) (a) Figure 49 4 17.00 4.25 Close Access 1 1.00 1.00 TOTAL FOR EACH AIRPLANE 262.00 60.75 (a) More time will be necessary for repairs if any crack is found. (b) More time will be necessary to inspect time limited repairs. (c) More time will be necessary to perform internal inspections if required. Group 2:
**Task Number of**  **Persons Task Hours Elapsed Hours** Open Access 1 1.00 1.00 Figure 4 6 156.00 26.00 Figure 12 4 59.00 14.75 Figure 17 - (a) (a) Figure 18 - (b) (b) Figure 23 4 55.00 13.75 Figure 28 1 2.00 2.00 Figure 30 - (c) (c) Figure 33 1 4.00 4.00 Figure 38 - (a) (a) Figure 40 4 20.00 5.00 Close Access 1 1.00 1.00 TOTAL FOR EACH AIRPLANE 298.00 67.50 (a) More time will be necessary for repairs if any crack is found. (b) More time will be necessary to inspect time limited repairs. (c) More time will be necessary to perform internal inspections if required.Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 67 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT** Group 3:
**Task Number of**  **Persons Task Hours Elapsed Hours** Open Access 4 8.00 2.00 Figure 5 6 396.00 66.00 Figure 10 4 45.00 (d) 11.25 (d) Figure 13 4 59.00 14.75 Figure 17 - (a) (a) Figure 18 - (b) (b) Figure 23 4 55.00 13.75 Figure 24 - (a) (a) Figure 26 6 75.00 12.50 Figure 28 1 2.00 2.00 Figure 30 - (c) (c) Figure 34 4 17.00 14.25 Figure 35 2 5.00 2.50 Figure 38 - (a) (a) Figure 39 4 23.00 5.75 Figure 42 1 4.00 4.00 Figure 48 1 1.25 1.25 Close Access 4 8.00 2.00 TOTAL FOR EACH AIRPLANE 653.25 140.75 (a) More time will be necessary for repairs if any crack is found. (b) More time will be necessary to inspect time limited repairs. (c) More time will be necessary to perform internal inspections if required. (d) Estimate does not include time to manufacture parts. Group 4:
**Task Number of**  **Persons Task Hours Elapsed Hours** Open Access 1 1.00 1.00 Figure 6 6 441.00 73.50 Figure 14 4 35.00 8.75 Figure 17 - (a) (a) Figure 18 - (b) (b) Figure 22 4 40.00 10.00 Figure 23 4 55.00 13.75 Figure 25 4 27.00 6.75 Figure 28 1 2.00 2.00 Figure 30 - (c) (c) Figure 31 1 2.00 2.00Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 68 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT**

Figure 36 1 1.25 1.25 Figure 38 - (a) (a) Figure 43 4 10.00 2.50 Close Access 1 1.00 1.00 TOTAL FOR EACH AIRPLANE 615.25 122.50 (a) More time will be necessary for repairs if any crack is found. (b) More time will be necessary to inspect time limited repairs. (c) More time will be necessary to perform internal inspections if required. Group 5:
**Task Number of**  **Persons Task Hours Elapsed Hours** Open Access 4 8.00 2.00 Figure 7 6 357.00 59.50 Figure 10 4 45.00 (d) 11.25 (d) Figure 15 4 27.00 6.75 Figure 17 - (a) (a) Figure 18 - (b) (b) Figure 22 4 40.00 10.00 Figure 23 4 55.00 13.75 Figure 24 - (a) (a) Figure 27 4 11.00 2.75 Figure 28 1 2.00 2.00 Figure 30 - (c) (c) Figure 37 1 1.25 1.25 Figure 38 - (a) (a) Figure 40 4 20.00 5.00 Figure 44 1 4.00 4.00 Figure 48 1 1.25 1.25 Close Access 4 8.00 2.00 TOTAL FOR EACH AIRPLANE 534.50 110.25 (a) More time will be necessary for repairs if any crack is found. (b) More time will be necessary to inspect time limited repairs. (c) More time will be necessary to perform internal inspections if required. (d) Estimate does not include time to manufacture parts. Group 4:
**Task Number of**  **Persons Task Hours Elapsed Hours**Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 69 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT** Group 6:
**Task Number of**  **Persons Task Hours Elapsed Hours** Open Access 1 1.00 1.00 Figure 17 - (a) (a) Figure 18 - (c) (c) Figure 21 4 12.00 3.00 Figure 26 6 75.00 12.50 Figure 29 4 44.00 11.00 Figure 30 - (a) (a) Figure 38 - (b) (b) Close Access 1 1.00 1.00 TOTAL FOR EACH AIRPLANE 133.00 28.5 (a) More time will be necessary to perform internal inspections if required. (b) More time will be necessary for repairs if any crack is found. (c) More time will be necessary to inspect time limited repairs. Group 7:
**Task Number of**  **Persons Task Hours Elapsed Hours** Open Access 1 1.00 1.00 Figure 14 4 35.00 8.75 Figure 17 - (a) (a) Figure 18 - (c) (c) Figure 21 4 12.00 3.00 Figure 30 - (a) (a) Figure 31 1 2.00 2.00 Figure 38 - (b) (b) Close Access 1 1.00 1.00 TOTAL FOR EACH AIRPLANE 51.00 15.75 (a) More time will be necessary to perform internal inspections if required. (b) More time will be necessary for repairs if any crack is found. (c) More time will be necessary to inspect time limited repairs. Group 8:
**Task Number of**  **Persons Task Hours Elapsed Hours** Open Access 1 1.00 1.00 Figure 15 4 27.00 6.75 Figure 17 - (a) (a) Figure 18 - (c) (c)Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 70 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT**

Figure 21 4 12.00 3.00 Figure 27 4 11.00 2.75 Figure 30 - (a) (a) Figure 38 - (b) (b) Close Access 1 1.00 1.00 TOTAL FOR EACH AIRPLANE 52.00 14.50 (a) More time will be necessary to perform internal inspections if required. (b) More time will be necessary for repairs if any crack is found. (c) More time will be necessary to inspect time limited repairs. Group 9-10:
**Task Number of**  **Persons Task Hours Elapsed Hours** Open Access 4 8.00 2.00 Figure 5 6 396.00 66.00 Figure 10 4 45.00 (d) 11.25 (d) Figure 17 - (a) (a) Figure 18 - (b) (b) Figure 21 4 12.00 3.00 Figure 23 4 55.00 13.75 Figure 24 - (a) (a) Figure 26 6 75.00 12.50 Figure 29 4 44.00 11.00 Figure 30 - (c) (c) Figure 34 4 17.00 4.25 Figure 35 2 5.00 2.50 Figure 38 - (a) (a) Figure 39 4 23.00 5.75 Figure 42 1 4.00 4.00 Figure 48 1 1.25 1.25 Close Access 4 8.00 2.00 TOTAL FOR EACH AIRPLANE 648.25 128.00 (a) More time will be necessary for repairs if any crack is found. (b) More time will be necessary to inspect time limited repairs. (c) More time will be necessary to perform internal inspections if required. (d) Estimate does not include time to manufacture parts. Group 8:
**Task Number of**  **Persons Task Hours Elapsed Hours**Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 71 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT** Group 11:
**Task Number of**  **Persons Task Hours Elapsed Hours** Open Access 1 1.00 1.00 Figure 6 6 441.00 73.50 Figure 14 4 35.00 8.75 Figure 17 - (a) (a) Figure 18 - (b) (b) Figure 21 4 12.00 3.00 Figure 23 4 55.00 13.75 Figure 25 4 27.00 6.75 Figure 30 - (c) (c) Figure 31 1 2.00 2.00 Figure 36 1 1.25 1.25 Figure 38 - (a) (a) Figure 43 4 10.00 2.50 Close Access 1 1.00 1.00 TOTAL FOR EACH AIRPLANE 585.25 113.50 (a) More time will be necessary for repairs if any crack is found. (b) More time will be necessary to inspect time limited repairs. (c) More time will be necessary to perform internal inspections if required. Group 12:
**Task Number of**  **Persons Task Hours Elapsed Hours** Open Access 4 8.00 2.00 Figure 7 6 357.00 59.50 Figure 10 4 45.00 (d) 11.25 (d) Figure 15 4 27.00 6.75 Figure 17 - (a) (a) Figure 18 - (b) (b) Figure 21 4 12.00 3.00 Figure 23 4 55.00 13.75 Figure 24 - (a) (a) Figure 27 4 11.00 2.75 Figure 30 - (c) (c) Figure 37 1 1.25 1.25 Figure 38 - (a) (a) Figure 40 4 20.00 5.00 Figure 44 1 4.00 4.00 Figure 48 1 1.25 1.25Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 72 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT**

Close Access 4 8.00 2.00 TOTAL FOR EACH AIRPLANE 504.50 101.25 (a) More time will be necessary for repairs if any crack is found. (b) More time will be necessary to inspect time limited repairs. (c) More time will be necessary to perform internal inspections if required. (d) Estimate does not include time to manufacture parts. Group 13:
**Task Number of**  **Persons Task Hours Elapsed Hours** Open Access 1 1.00 1.00 Figure 4 6 156.00 26.00 Figure 17 - (a) (a) Figure 18 - (b) (b) Figure 22 4 40.00 10.00 Figure 23 4 55.00 13.75 Figure 28 1 2.00 2.00 Figure 30 - (c) (c) Figure 33 1 4.00 4.00 Figure 38 - (a) (a) Figure 40 4 20.00 5.00 Figure 41 4 44.00 11.00 Close Access 1 1.00 1.00 TOTAL FOR EACH AIRPLANE 323.00 73.75 (a) More time will be necessary for repairs if any crack is found. (b) More time will be necessary to inspect time limited repairs. (c) More time will be necessary to perform internal inspections if required. Group 14:
**Task Number of**  **Persons Task Hours Elapsed Hours** Open Access 4 8.00 2.00 Figure 5 6 396.00 66.00 Figure 10 4 45.00 (d) 11.25 (d) Figure 17 - (a) (a) Figure 18 - (b) (b) Figure 22 4 40.00 10.00 Figure 23 4 55.00 13.75 Group 12:
**Task Number of**  **Persons Task Hours Elapsed Hours**Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 73 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT**

Figure 24 - (a) (a) Figure 26 6 75.00 12.50 Figure 28 1 2.00 2.00 Figure 29 4 44.00 11.00 Figure 30 - (c) (c) Figure 34 4 17.00 4.25 Figure 35 2 5.00 2.50 Figure 38 - (a) (a) Figure 39 4 23.00 5.75 Figure 42 1 4.00 4.00 Figure 48 1 1.25 1.25 Close Access 4 8.00 2.00 TOTAL FOR EACH AIRPLANE 678.25 137.00 (a) More time will be necessary for repairs if any crack is found. (b) More time will be necessary to inspect time limited repairs. (c) More time will be necessary to perform internal inspections if required. (d) Estimate does not include time to manufacture parts. Group 15:
**Task Number of**  **Persons Task Hours Elapsed Hours** Open Access 4 8.00 2.00 Figure 5 6 396.00 66.00 Figure 10 4 45.00 (d) 11.25 (d) Figure 17 - (a) (a) Figure 18 - (b) (b) Figure 21 4 12.00 3.00 Figure 23 4 55.00 13.75 Figure 24 - (a) (a) Figure 26 6 75.00 12.50 Figure 29 4 44.00 11.00 Figure 30 - (c) (c) Figure 34 4 17.00 4.25 Figure 35 2 5.00 2.50 Figure 38 - (a) (a) Figure 39 4 23.00 5.75 Figure 42 1 4.00 4.00 Figure 48 1 1.25 1.25 Group 14:
**Task Number of**  **Persons Task Hours Elapsed Hours**Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 74 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT**

Close Access 4 8.00 2.00 TOTAL FOR EACH AIRPLANE 648.25 128.00 (a) More time will be necessary for repairs if any crack is found. (b) More time will be necessary to inspect time limited repairs. (c) More time will be necessary to perform internal inspections if required. (d) Estimate does not include time to manufacture parts. Group 16:
**Task Number of**  **Persons Task Hours Elapsed Hours** Open Access 1 1.00 1.00 Figure 6 6 441.00 73.50 Figure 14 4 35.00 8.75 Figure 17 - (a) (a) Figure 18 - (b) (b) Figure 21 4 12.00 3.00 Figure 23 4 55.00 13.75 Figure 25 4 27.00 6.75 Figure 30 - (c) (c) Figure 31 1 2.00 2.00 Figure 36 1 1.25 1.25 Figure 38 - (a) (a) Figure 43 4 10.00 2.50 Close Access 1 1.00 1.00 TOTAL FOR EACH AIRPLANE 585.25 113.50 (a) More time will be necessary for repairs if any crack is found. (b) More time will be necessary to inspect time limited repairs. (c) More time will be necessary to perform internal inspections if required. Group 17:
**Task Number of**  **Persons Task Hours Elapsed Hours** Open Access 4 8.00 2.00 Figure 7 6 357.00 59.50 Figure 10 4 45.00 (d) 11.25 (d) Figure 15 4 27.00 6.75 Figure 17 - (a) (a) Figure 18 - (b) (b) Group 15:
**Task Number of**  **Persons Task Hours Elapsed Hours**Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 75 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT**

Figure 21 4 12.00 3.00 Figure 23 4 55.00 13.75 Figure 24 - (a) (a) Figure 27 4 11.00 2.75 Figure 30 - (c) (c) Figure 37 1 1.25 1.25 Figure 38 - (a) (a) Figure 40 4 20.00 5.00 Figure 44 1 4.00 4.00 Figure 48 1 1.25 1.25 Close Access 4 8.00 2.00 TOTAL FOR EACH AIRPLANE 504.50 101.25 (a) More time will be necessary for repairs if any crack is found. (b) More time will be necessary to inspect time limited repairs. (c) More time will be necessary to perform internal inspections if required. (d) Estimate does not include time to manufacture parts. Group 18:
**Task Number of**  **Persons Task Hours Elapsed Hours** Open Access 4 8.00 2.00 Figure 10 4 45.00 (d) 11.25 (d) Figure 17 - (a) (a) Figure 18 - (b) (b) Figure 21 4 12.00 3.00 Figure 23 4 55.00 13.75 Figure 24 - (a) (a) Figure 26 6 75.00 12.50 Figure 29 4 44.00 11.00 Figure 30 - (c) (c) Figure 34 4 17.00 4.25 Figure 35 2 5.00 2.50 Figure 38 - (a) (a) Figure 42 1 4.00 4.00 Figure 45 6 291.00 48.50 Figure 47 4 17.00 4.25 Figure 48 1 1.25 1.25 Close Access 4 8.00 2.00 Group 17:
**Task Number of**  **Persons Task Hours Elapsed Hours**Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 76 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT**

TOTAL FOR EACH AIRPLANE 582.25 120.25 (a) More time will be necessary for repairs if any crack is found. (b) More time will be necessary to inspect time limited repairs. (c) More time will be necessary to perform internal inspections if required. (d) Estimate does not include time to manufacture parts. Group 19:
**Task Number of**  **Persons Task Hours Elapsed Hours** Open Access 4 8.00 2.00 Figure 10 4 45.00 (d) 11.25 (d) Figure 15 4 27.00 6.75 Figure 17 - (a) (a) Figure 18 - (b) (b) Figure 22 4 40.00 10.00 Figure 23 4 55.00 13.75 Figure 24 - (a) (a) Figure 27 4 11.00 2.75 Figure 28 1 2.00 2.00 Figure 30 - (c) (c) Figure 37 1 1.25 1.25 Figure 38 - (a) (a) Figure 44 1 4.00 4.00 Figure 46 6 267.00 44.50 Figure 47 4 17.00 4.25 Figure 48 1 1.25 1.25 Close Access 4 8.00 2.00 TOTAL FOR EACH AIRPLANE 441.50 94.50 (a) More time will be necessary for repairs if any crack is found. (b) More time will be necessary to inspect time limited repairs. (c) More time will be necessary to perform internal inspections if required. (d) Estimate does not include time to manufacture parts. Group 18:
**Task Number of**  **Persons Task Hours Elapsed Hours**Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 77 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT** Group 20:
**Task Number of**  **Persons Task Hours Elapsed Hours** Open Access 4 8.00 2.00 Figure 10 4 45.00 (d) 11.25 (d) Figure 15 4 27.00 6.75 Figure 17 - (a) (a) Figure 18 - (b) (b) Figure 21 4 12.00 3.00 Figure 23 4 55.00 13.75 Figure 24 - (a) (a) Figure 27 4 11.00 2.75 Figure 30 - (c) (c) Figure 37 1 1.25 1.25 Figure 38 - (a) (a) Figure 44 1 4.00 4.00 Figure 46 6 267.00 44.50 Figure 47 4 17.00 4.25 Figure 48 1 1.25 1.25 Close Access 4 8.00 2.00 TOTAL FOR EACH AIRPLANE 411.50 85.50 (a) More time will be necessary for repairs if any crack is found. (b) More time will be necessary to inspect time limited repairs. (c) More time will be necessary to perform internal inspections if required. (d) Estimate does not include time to manufacture parts. (e) More time will be necessary to perform post repair inspections. Group 21:
**Task Number of**  **Persons Task Hours Elapsed Hours** Open Access 4 8.00 2.00 Figure 10 4 45.00 (d) 11.25 (d) Figure 17 - (a) (a) Figure 18 - (b) (b) Figure 22 4 40.00 10.00 Figure 23 4 55.00 13.75 Figure 24 - (a) (a) Figure 26 6 75.00 12.50 Figure 28 1 2.00 2.00 Figure 29 4 44.00 11.00 Figure 30 - (c) (c)Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 78 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT**

**H. Weight and Balance Changes**

**I. Electrical Load Data** Not changed Figure 34 4 17.00 4.25 Figure 35 2 5.00 2.50 Figure 38 - (a) (a) Figure 42 1 4.00 4.00 Figure 45 6 291.00 48.50 Figure 47 4 17.00 4.25 Figure 48 1 1.25 1.25 Close Access 4 8.00 2.00 TOTAL FOR EACH AIRPLANE 612.25 129.25 (a) More time will be necessary for repairs if any crack is found. (b) More time will be necessary to inspect time limited repairs. (c) More time will be necessary to perform internal inspections if required. (d) Estimate does not include time to manufacture parts.

**Service Bulletin Repair Figure Change in Weight (Pounds) +{-}**  **Change in Moment (Pound-Inches) +{-}**  Figure 10 - Preventive Modification +2.4 (b) (d) Figure 17 and 38 - Time limited Skin Repair +0.6 (a) (b) (c) (d) Figure 24 - Stringer S-12 crack repair +3.5 (b) (d) (a) For 737-200 airplanes measure the straight - line “X” distance in inches from the airplane's nose to the center of the repair. Add 94 inches to get the Balance Arm (BA). Multiply BA times the weight of the repair. The product is the desired “Change in Moment”. (b) For 737-300 airplanes measure the straight - line “X” distance in inches from the airplane's nose to the center of the repair. Add 50 inches to get the Balance Arm (BA). Multiply BA times the weight of the repair. The product is the desired “Change in Moment”. (c) For 737-400 airplanes measure the straight - line “X” distance in inches from the airplane's nose to the center of the repair. Subtract 22 inches to get the Balance Arm (BA). Multiply BA times the weight of the repair. The product is the desired “Change in Moment”. (d) For 737-500 airplanes measure the straight - line “X” distance in inches from the airplane's nose to the center of the repair. Add 104 inches to get the Balance Arm (BA). Multiply BA times the weight of the repair. The product is the desired “Change in Moment”. Example: A 737-400 received one Figure 10, 17 and 24 modification at “X” distance measured as 400, 600 and 800 inches respectively. What is the Change in Moment? Answer: (400-22)(2.4)=907, (600-22)(0.6)=347 and (800-22)(3.5)=2,723 Summing 907+347+2,723 = 3,977 Pound - Inches Group 21:
**Task Number of**  **Persons Task Hours Elapsed Hours**Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 79 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT J. References**  1. Existing Data: a. 737-100/200 Aircraft Maintenance Manual (AMM) 25-21-311, 25-21-341, 25-21-347, 25-22-0, 25-23-311, 25-24-311, 53-51-11, 53-51-21. b. 737-100/200 Structural Repair Manual (SRM) 51-30-08, 53-30-3. c. 737-300 Structural Repair Manual (SRM) 51-10-01, 51-20-01, 51-20-05, 51-40-08, 53-00-01. d. 737-300/400/500 Aircraft Maintenance Manual (AMM) 25-21-39, 25-21-45, 25-21-46, 25-22-00, 25-23-61, 25-24-31, 25-27-15, 25-52-73, 51-21-00, 53-51-19, 53-51-20, 53-51-21 e. 737-400 Structural Repair Manual (SRM) 51-20-05, 51-40-08, 53-00-01. f. 737-500 Structural Repair Manual (SRM) 51-10-01, 51-20-01, 51-20-05, 51-40-08, 53-00-01. g. 737 Non-Destructive Testing (NDT) Manual, Part 6, 51-00-00, Part 6, 51-30-00, Part 6, 53-30-00, Part 6, 53-30-05, Part 6, 53-30-09, Part 6, 53-30-12, Part 6, 53-30-16, Part 6, 53-30-18, Part 6, 53-30-19, Part 6, 53-30-20, Part 6, 53-30-20., Part 6, 53-30-25. h. Boeing Document D6-56722, Customer Cost Benefit Methodology Guide. i. Boeing Service Bulletins 737-53-1065, “Fuselage - Aft Skin - Inspection, Repair, and Modification” 737-53A1039, “Fuselage Skin Lap Joint Inspection and Repair” 737-53-1076, “Fuselage - Circumferential Butt Splices and Bonded Doublers - Inspection, Repair and Modification” 737-53-1078, “Fuselage Window Belt Skin Panel Inspection and Repair” 737-53-1124, “Fuselage - Bonded Doublers (Tear Straps) - Inspection and Repair For Delamination Above Stringer 26 Between Stations 259 and 1016" 737-53-1168, “Fuselage - Aft Skin - Inspection, Modification, and Replacement” 737-53A1177, “Fuselage - Skin - Repair Methods For Cracks in Lower Skins at Lap Joints” 737-53-1178, “Fuselage Frames - STA 663.75, Outboard Chord at Stringers 1, 2, 3, 4, and 5 Inspection and Preventive Modification” 737-53-1179, “Fuselage - Bonded Skin Doublers (Tear Straps) - Delamination Inspection and Repair” 737-53-1187, “Fuselage - Aft Skin - Inspection - Modification And Replacement” SIIA 737-242, “Fuselage - Plates and Skin - Skin Crack Between Stringers 11 and 13 at Station 500D + 10 j. Standard Overhaul Practices Manual (SOPM) 20-50-12, 20-50-19. k. FAA Airworthiness Directive 2004-18-06 and 98-11-04 R1. 2. Data supplied with this Service Bulletin:
None.Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 80 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT**

3. Installation Drawings Used in the Preparation of this Service Bulletin:

These drawings were used to prepare this service bulletin. These drawings are not necessary to make the specified changes, and are not supplied with this service bulletin. These drawings may not be applicable to all airplane configurations or operators. **K. Publications Affected**
1. Publications None. 2. Damage Tolerance Based Structural Inspections: Boeing has evaluated the repairs and/or changes in this service bulletin for effects on Fatigue Critical Structure (FCS) and for changes to Damage Tolerance Inspections (DTI) required in the Maintenance Program. This service bulletin affects FCS and new DTI requirements for the structure affected are contained in Paragraph 1.E., Compliance of this service bulletin. **L. Interchangeability and Intermixability of Parts**
None. **Drawing Number Title** 65-73742 Skin Diagram Body Model 737 65-45766 Panel Instl - STA 360 to STA 540 S-10 to S-14 65C32356 Skin Assy - Window STA 360 to STA 54 S-10 to S-14Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 81 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT 2. MATERIAL INFORMATION**  **A. Material - Price and Availability** None **B. Industry Support Information** Boeing warranty remedies are not available for the inspection and 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: **NOTE:** The parts that follow are used to accomplish a typical time-limited skin repair as given in Figure 17. Number of fasteners, size, type, and grip length may vary, depending on the specific repair.
**Part Number / Specification QTY Name Notes**  A 1 Doubler (a) B 1 Filler (a) C 1 Filler (a) BACR15FR5E2R 68 Rivet (b) BACR15FR5E3R 63 Rivet (b) BACR15FR5E4R 25 Rivet (b) BACR15FR6E3R 3 Rivet (c) BACR15FR6E4R 6 Rivet (c) BMS 5-95 AR Sealant (d) (a) Make as given in Figure 17. (b) NAS1738E5-( ) Optional. (c) NAS1738E6-( ) Optional. (d) See the Qualified Products List at the end of the Boeing Material Specification (BMS) for supplier data.Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 82 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT NOTE:**  The parts that follow are used to modify a typical time-limited skin repair into a permanent skin repair as given in Figure 10. Number of fasteners, size, type, and grip length may vary, depending on the specific repair.

**NOTE:** The parts that follow are used to install a stringer 12 repair as given in Figure 24. Number of fasteners, size, type, and grip length may vary, depending on the specific repair. **Part Number / Specification QTY Name Notes**  A 1 Internal Doubler (a) B 4 Pocket Filler (a) C 1 Filler, under S-12 (a) D 8 Tapered shim (a) BACR15BB5D( ) 74 Rivet BACR15CE6D( ) 103 Rivet BAC1534-33F AR Shim BMS 5-95 Class B-1/2, -2 16 ounces Sealant (b) BMS 3-23 4 ounces Corrosion Inhibitor (b) (a) Make as given in Figure 10. (b) See the Qualified Products List at the end of the Boeing Material Specification (BMS) for supplier data.

**Part Number / Specification QTY Name Notes**  .032 inch 2024-T3 1 Doubler (a) .050 inch 2024-T3 1 Tripler (a) .040 inch 2024-T3 1 Tapered Filler (a) .040 inch 2024-T3 1 Tapered Filler (a) BACR15BB6AD( ) 38 Rivet (b) BACR15CE5D( ) 153 Rivet (b) BACR15BB6D( ) 47 Rivet (b) BACR15BB10D( ) 16 Rivet (b) BACB30FM10A( ) 16 Bolt (b)(c) BACC30M10 16 Nut (b)(c) Type 2, Class A 4 Ounces Chemical Conversion Coating (b) BMS 5-95 Class B-1/2, -2 16 ounces Sealant (b) BMS 3-23 4 ounces Corrosion Inhibitor (b) BMS10-79 type II or type III primer 1/2 Pint Primer (a) (a) Make as given in Figure 24. (b) See the Qualified Products List at the end of the Boeing Material Specification (BMS) for supplier data. (c) These parts are only required if the existing fasteners were nuts and bolts.Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 83 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT NOTE:**  The parts that follow are used to accomplish a typical time-limited skin repair as given in Figure 38.

**NOTE:** The parts that follow are used to modify the typical time-limited skin repair given in Figure 38 into a permanent skin repair.

3. Parts Modified and Reidentified:
None. **Part Number / Specification QTY Name Notes**  2024-T3 clad sheet 1 Repair Doubler (a) BACR15FR5E5R or BACR15FR5E6R As Required Rivet (b)
BACR15FR6E6R or BACR15FR6E7R As Required Rivet (b) BMS 5-95 Class B-1/2, -2 16 ounces Sealant (c) (d) BMS10-79 type II or type III primer 1/2 Pint Primer (c) (a) Make as given in Figure 38. (b) Refer to 737 Structural Repair Manual Chapter 51 for alternative fasteners. (c) See the Qualified Products List at the end of the Boeing Material Specification (BMS) for supplier data. (d) See SOPM 20-50-12.

**Part Number / Specification QTY Name Notes**  2024-T3 clad sheet 1 Repair Doubler (a) BACR15BB6AD6 or BACR15BB6AD7 or BACR15BB7AD7 or BACR15BB7AD8 As Required Rivet (b)

BACR15FR6E6R or BACR15FR6E7R As Required Rivet (b) BMS 5-95 Class B-1/2, -2 16 ounces Sealant (c) (d) BMS10-79 type II or type III primer 1/2 Pint Primer (c) BMS 3-23 4 ounces Corrosion Inhibitor (c) (a) Make as given in Figure 38. (b) Refer to 737 Structural Repair Manual Chapter 51 for alternative fasteners. (c) See the Qualified Products List at the end of the Boeing Material Specification (BMS) for supplier data. (d) See SOPM 20-50-12.Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 84 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT**

4. Parts Removed and Not Replaced: None. **D. Parts Necessary to Change Spares**
None **E. Special Tooling - Price and Availability**
None **F. Special Tooling Necessary to do this Service Bulletin** No special tools or equipment are necessary to do the change in this service bulletin. But, maintenance and overhaul tools in the manuals given in Paragraph 1.J., References, can be necessary. Examine operator tool supply to make sure all necessary tools are available.Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 85 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT 3. ACCOMPLISHMENT INSTRUCTIONS**  **A. GENERAL INFORMATION CAUTION:**  KEEP THE WORK AREA, WIRES AND ELECTRICAL BUNDLES CLEAN OF METAL PARTICLES OR CONTAMINATION WHEN YOU USE TOOLS. UNWANTED MATERIAL, METAL PARTICLES OR CONTAMINATION CAUGHT IN WIRE BUNDLES CAN CAUSE DAMAGE TO THE BUNDLES. DAMAGED WIRE BUNDLES CAN CAUSE SPARKS OR OTHER ELECTRICAL DAMAGE. **NOTE:** 1. Manual titles are referred to by acronyms. Refer to Paragraph 1.J., References, for definition of the acronyms. 2. Obey all of the warnings and cautions given in the specified manual sections. 3. Unless shown differently, these dimensions and tolerances are used: — Linear dimensions are in inches — Tolerance on linear dimensions, other than rivet and bolt edge margins, is plus or minus 0.03 inch. — Tolerance on rivet and 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 737 SRM, Chapter 51 — Torque limits to tighten nuts and bolts are given in 737 SRM, Chapter 51. 4. For approved fastener and process material substitutions, refer to 737 SRM, Chapter 51, Alternate fasteners are given in 737 SRM Chapter 51 and Boeing Drawing 65-88700. 5. If the length of any fastener specified in this service bulletin does not meet the installation standards given in SRM Chapter 51, then a fastener of the same specification, or an approved substitute, with a length which meets the installation standards given in SRM Chapter 51 may be used. 6. 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. 7. A General Visual Inspection is defined as: A visual examination of an interior or exterior area, installation or assembly to detect obvious damage, failure or irregularity. This level of inspection is made from within touching distance unless otherwise specified. A mirror may be necessary to ensure visual access to all surfaces in the inspection area. This level of inspection is made under normal available lighting conditions such as daylight, hangar lighting, flashlight or drop-light and may require removal or opening of access panels or doors. Stands, ladders or platforms may be required to gain proximity to the area being checked. 8. These work instructions refer to procedures included on 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 “as given in” areOriginal Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 86 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT** included in the instruction, the procedure in the Boeing document must be used. 9. Refer to Appendix A for Cost Benefit Analysis. 10. Some areas identified for chem-mill inspections may not have a chem-mill step depending on the specific airplane skin configuration. If a chem-mill step does not exist in an area identified for inspection in this service bulletin, then the inspection is not required in that specific area. 11. Some areas identified for chem-mill inspections may not be chem-milled all of the way through the bonded doubler to the bond line. Inspections as given in this service bulletin are not required in these areas where the chem-mill is not completely through the thickness of the bonded doubler. This cannot be determined visually. Drawing verification is required. **B. WORK INSTRUCTIONS** 1. PART 1 - CROWN AREA SKIN INSPECTION a. Group 1: (1) Do an external detailed inspection and eddy current inspection of the fuselage skin for any crack as given in Figure 3. **NOTE:** For non lap splice areas between STA 360 to STA 1016 and S-10L to S-10R it is optional to do general visual inspections at reduced intervals in lieu of the detailed inspections. Refer to Paragraph 1.E., Compliance. (2) Do a High Frequency Eddy Current (HFEC) sliding probe inspection of the fuselage skin at tear strap attachments as given in Figure 23. **NOTE:** These inspections are only required at tearstrap tab locations where chem-mill step inspections are required. If a tearstrap tab detail as shown in Figure 23 does not exist in a chem-mill inspection area then the inspections as given in Figure 23 are not required at that location. (3) Do an external detailed inspection and eddy current inspection of the fuselage skin for cracks as given in Figure 32. (4) If any crack is found in the above inspections, do one of the options that follow: (a) Option 1 - Do the PERMANENT REPAIR as given in PART 5. 1) If the permanent repairs given in PART 5 are not applicable, contact Boeing for repair instructions and install the repair. (b) Option 2 - Do the TIME-LIMITED REPAIR as given in PART 6, then inspect and replace at the times given in Paragraph 1.E., Compliance. 1) If the time-limited repair given in PART 6 is not applicable, either accomplish the permanent repair as given in Part 5 or contact Boeing for repair instructions and install the repair.Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 87 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT** (5) If no crack is found in the above inspections, do the inspections again at the times given in Paragraph 1.E., Compliance. b. Group 2, 13: (1) Do an external detailed inspection and eddy current inspection of the fuselage skin for any crack as given in Figure 4. **NOTE:** For non lap splice areas between STA 360 to STA 1016 and S-10L to S-10R it is optional to do general visual inspections at reduced intervals in lieu of the detailed inspections. Refer to Paragraph 1.E., Compliance. (2) Do a High Frequency Eddy Current (HFEC) sliding probe inspection of the fuselage skin at tear strap attachments as given in Figure 23. **NOTE:** These inspections are only required at tearstrap tab locations where chem-mill step inspections are required. If a tearstrap tab detail as shown in Figure 23 does not exist in a chem-mill inspection area then the inspections as given in Figure 23 are not required at that location. (3) Do an external detailed inspection and eddy current inspection of the fuselage skin for cracks as given in Figure 33. (4) If any crack is found in the above inspections, do one of the options that follow: (a) Option 1 - Do the PERMANENT REPAIR as given in PART 5. 1) If the permanent repairs given in PART 5 are not applicable, contact Boeing for repair instructions and install the repair. (b) Option 2 - Do the TIME-LIMITED REPAIR as given in PART 6, then inspect and replace at the times given in Paragraph 1.E., Compliance. 1) If the time-limited repair given in PART 6 is not applicable, either accomplish the permanent repair as given in Part 5 or contact Boeing for repair instructions and install the repair. (5) If no crack is found in the above inspections, do the inspections again at the times given in Paragraph 1.E., Compliance. c. Group 3, 9-10, 14-15: (1) Do an external detailed inspection and eddy current inspection of the fuselage skin for any crack as given in Figure 5. **NOTE:** For non lap splice areas between STA 360 to STA 1016 and S-10L to S-10R it is optional to do general visual inspections at reduced intervals in lieu of the detailed inspections. Refer to Paragraph 1.E., Compliance. (2) Do a High Frequency Eddy Current (HFEC) sliding probe inspection of the fuselage skin at tear strap attachments as given in Figure 23.Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 88 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT NOTE:**  These inspections are only required at tearstrap tab locations where chem-mill step inspections are required. If a tearstrap tab detail as shown in Figure 23 does not exist in a chem-mill inspection area then the inspections as given in Figure 23 are not required at that location. (3) Do an external detailed inspection and eddy current inspection of the fuselage skin for cracks as given in Figure 34. (4) Do an external detailed inspection and eddy current inspection of the fuselage skin for cracks as given in Figure 35. (5) If any crack is found in the above inspections, do one of the options that follow: (a) Option 1 - Do the PERMANENT REPAIR as given in PART 5. 1) If the permanent repairs given in PART 5 are not applicable, contact Boeing for repair instructions and install the repair. (b) Option 2 - Do the TIME-LIMITED REPAIR as given in PART 6, then inspect and replace at the times given in Paragraph 1.E., Compliance. 1) If the time-limited repair given in PART 6 is not applicable, either accomplish the permanent repair as given in Part 5 or contact Boeing for repair instructions and install the repair. (6) If no crack is found in the above inspections, do the inspections again at the times given in Paragraph 1.E., Compliance. d. Group 4, 11, 16: (1) Do an external detailed inspection and eddy current inspection of the fuselage skin for any crack as given in Figure 6. **NOTE:** For non lap splice areas between STA 360 to STA 1016 and S-10L to S-10R it is optional to do general visual inspections at reduced intervals in lieu of the detailed inspections. Refer to Paragraph 1.E., Compliance. (2) Do a High Frequency Eddy Current (HFEC) sliding probe inspection of the fuselage skin at tear strap attachments as given in Figure 23. **NOTE:** These inspections are only required at tearstrap tab locations where chem-mill step inspections are required. If a tearstrap tab detail as shown in Figure 23 does not exist in a chem-mill inspection area then the inspections as given in Figure 23 are not required at that location. (3) Do an external detailed inspection and eddy current inspection of the fuselage skin for cracks as given in Figure 36. (4) If any crack is found in the above inspections, do one of the options that follow: (a) Option 1 - Do the PERMANENT REPAIR as given in PART 5.Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 89 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT** 1) If the permanent repairs given in PART 5 are not applicable, contact Boeing for repair instructions and install the repair. (b) Option 2 - Do the TIME-LIMITED REPAIR as given in PART 6, then inspect and replace at the times given in Paragraph 1.E., Compliance. 1) If the time-limited repair given in PART 6 is not applicable, either accomplish the permanent repair as given in Part 5 or contact Boeing for repair instructions and install the repair. (5) If no crack is found in the above inspections, do the inspections again at the times given in Paragraph 1.E., Compliance. e. Group 5, 12, 17: (1) Do an external detailed inspection and eddy current inspection of the fuselage skin for any crack as given in Figure 7. **NOTE:** For non lap splice areas between STA 360 to STA 1016 and S-10L to S-10R it is optional to do general visual inspections at reduced intervals in lieu of the detailed inspections. Refer to Paragraph 1.E., Compliance. (2) Do a High Frequency Eddy Current (HFEC) sliding probe inspection of the fuselage skin at tear strap attachments as given in Figure 23. **NOTE:** These inspections are only required at tearstrap tab locations where chem-mill step inspections are required. If a tearstrap tab detail as shown in Figure 23 does not exist in a chem-mill inspection area then the inspections as given in Figure 23 are not required at that location. (3) Do an external detailed inspection and eddy current inspection of the fuselage skin for cracks as given in Figure 37. (4) If any crack is found in the above inspections, do one of the options that follow: (a) Option 1 - Do the PERMANENT REPAIR as given in PART 5. 1) If the permanent repairs given in PART 5 are not applicable, contact Boeing for repair instructions and install the repair. (b) Option 2 - Do the TIME-LIMITED REPAIR as given in PART 6, then inspect and replace at the times given in Paragraph 1.E., Compliance. 1) If the time-limited repair given in PART 6 is not applicable, either accomplish the permanent repair as given in Part 5 or contact Boeing for repair instructions and install the repair. (5) If no crack is found in the above inspections, do the inspections again at the times given in Paragraph 1.E., Compliance.Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 90 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT** f. Group 18, 21: (1) Do an external detailed inspection and eddy current inspection of the fuselage skin for any crack as given in Figure 45. **NOTE:** For non lap splice areas between STA 360 to STA 1016 and S-10L to S-10R it is optional to do general visual inspections at reduced intervals in lieu of the detailed inspections. Refer to Paragraph 1.E., Compliance. (2) Do a High Frequency Eddy Current (HFEC) sliding probe inspection of the fuselage skin at tear strap attachments as given in Figure 23. **NOTE:** These inspections are only required at tearstrap tab locations where chem-mill step inspections are required. If a tearstrap tab detail as shown in Figure 23 does not exist in a chem-mill inspection area then the inspections as given in Figure 23 are not required at that location. (3) Do an external detailed inspection and eddy current inspection of the fuselage skin for cracks as given in Figure 34. (4) Do an external detailed inspection and eddy current inspection of the fuselage skin for cracks as given in Figure 35. (5) If any crack is found in the above inspections, do one of the options that follow: (a) Option 1 - Do the PERMANENT REPAIR as given in PART 5. 1) If the permanent repairs given in PART 5 are not applicable, contact Boeing for repair instructions and install the repair. (b) Option 2 - Do the TIME-LIMITED REPAIR as given in PART 6, then inspect and replace at the times given in Paragraph 1.E., Compliance. 1) If the time-limited repair given in PART 6 is not applicable, either accomplish the permanent repair as given in Part 5 or contact Boeing for repair instructions and install the repair. (6) If no crack is found in the above inspections, do the inspections again at the times given in Paragraph 1.E., Compliance. g. Group 19-20: (1) Do an external detailed inspection and eddy current inspection of the fuselage skin for any crack as given in Figure 46. **NOTE:** For non lap splice areas between STA 360 to STA 1016 and S-10L to S-10R it is optional to do general visual inspections at reduced intervals in lieu of the detailed inspections. Refer to Paragraph 1.E., Compliance. (2) Do a High Frequency Eddy Current (HFEC) sliding probe inspection of the fuselage skin at tear strap attachments as given in Figure 23.Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 91 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT NOTE:**  These inspections are only required at tearstrap tab locations where chem-mill step inspections are required. If a tearstrap tab detail as shown in Figure 23 does not exist in a chem-mill inspection area then the inspections as given in Figure 23 are not required at that location. (3) Do an external detailed inspection and eddy current inspection of the fuselage skin for cracks as given in Figure 37. (4) If any crack is found in the above inspections, do one of the options that follow: (a) Option 1 - Do the PERMANENT REPAIR as given in PART 5. 1) If the permanent repairs given in PART 5 are not applicable, contact Boeing for repair instructions and install the repair. (b) Option 2 - Do the TIME-LIMITED REPAIR as given in PART 6, then inspect and replace at the times given in Paragraph 1.E., Compliance. 1) If the time-limited repair given in PART 6 is not applicable, either accomplish the permanent repair as given in Part 5 or contact Boeing for repair instructions and install the repair. (5) If no crack is found in the above inspections, do the inspections again at the times given in Paragraph 1.E., Compliance. h. Put the airplane back to a serviceable condition. **NOTE:** 1. The inspections given in PART 1 are not necessary in areas repaired as given in Figure 42 or 48 of 737-100/200 SRM 53-30-3, or Repair 30 or 31 of 737-300 SRM 53-00-01, 737-400 SRM 53-00-01 or 737-500 SRM 53-00-01. Inspections are not required directly under the repair doubler. Do the inspections required in areas adjacent to the repair doubler. 2. The installation of external repair doublers as given in Boeing Service Bulletin 737-53A1177, Revision 2 or later constitutes terminating action for the PART 1 inspections in the repaired area only. 2. PART 2 - WINDOW BELT INSPECTION - HORIZONTAL CHEM-MILL LINE CRACKS a. Group 3, 9-10, 14-15, 18, 21: (1) Do an external detailed inspection and eddy current inspection of the fuselage skin for any crack in the window belt area between STA 500D and STA 520, S-10 to S-14 as given in Figure 42. (a) If any crack is found, do the repair as given in PART 8 - SKIN CHEM-MILL LINE CRACK AT STRINGER 12 - REPAIR INSTRUCTIONS. If the repair given in PART 8 is not applicable, contact Boeing for repair instructions and install the repair.Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 92 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT** (b) If no crack is found, do the inspections again at the times given in Paragraph 1.E., Compliance. As an option do the preventive modification as given in PART 7 - PREVENTIVE MODIFICATION. b. Group 4, 11, 16: (1) Do an external detailed inspection and eddy current inspection of the fuselage skin for any crack in the window belt area between STA 500E and STA 500F and STA 500G and STA 520, S-10 to S-14 as given in Figure 43. (a) If any crack is found, contact Boeing for repair instructions and install the repair. (b) If no crack is found, do the inspections again at the times given in Paragraph 1.E., Compliance. c. Group 5, 12, 17, 19-20: (1) Do an external detailed inspection and eddy current inspection of the fuselage skin for any crack window belt area between STA 482B to STA 520 and S-10 to S-14 as given in Figure 44. (a) If any crack is found, do the repair as given in PART 8 - SKIN CHEM-MILL LINE CRACK AT STRINGER 12 - REPAIR INSTRUCTIONS. If the repair given in PART 8 is not applicable, contact Boeing for repair instructions and install the repair. (b) If no crack is found, do the inspections again at the times given in Paragraph 1.E., Compliance. As an option do the preventive modification as given in PART 7 - PREVENTIVE MODIFICATION. d. Put the airplane back to a serviceable condition. 3. PART 3 - VERTICAL CRACK INSPECTION a. Group 2, 5, 12-13, 17: (1) Do an external detailed inspection and eddy current inspection of the fuselage skin for any crack as given in Figure 40. (a) If any crack is found, do the PERMANENT REPAIR as given in PART 5. 1) If the permanent repairs given in PART 5 are not applicable, contact Boeing for repair instructions and install the repair. (b) If no crack is found, do the inspections again at the times given in Paragraph 1.E., Compliance. b. Group 1: (1) Do an external detailed inspection and eddy current inspection of the fuselage skin for any crack as given in Figure 49. (a) If any crack is found, do the PERMANENT REPAIR as given in PART 5.Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 93 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT** 1) If the permanent repairs given in PART 5 are not applicable, contact Boeing for repair instructions and install the repair. (b) If no crack is found, do the inspections again at the times given in Paragraph 1.E., Compliance. c. Group 3, 9-10, 14-15: (1) Do an external detailed inspection and eddy current inspection of the fuselage skin for any crack as given in Figure 39. (a) If any crack is found, do the PERMANENT REPAIR as given in PART 5. 1) If the permanent repairs given in PART 5 are not applicable, contact Boeing for repair instructions and install the repair. (b) If no crack is found, do the inspections again at the times given in Paragraph 1.E., Compliance. d. Group 4, 11, 16: (1) Do an external detailed inspection and eddy current inspection of the fuselage skin for any crack as given in Figure 25. (a) If any crack is found, do the PERMANENT REPAIR as given in PART 5. 1) If the permanent repairs given in PART 5 are not applicable, contact Boeing for repair instructions and install the repair. (b) If no crack is found, do the inspections again at the times given in Paragraph 1.E., Compliance. e. Group 18-21: (1) Do an external detailed inspection and eddy current inspection of the fuselage skin for any crack as given in Figure 47. (a) If any crack is found, do the PERMANENT REPAIR as given in PART 5. 1) If the permanent repairs given in PART 5 are not applicable, contact Boeing for repair instructions and install the repair. (b) If no crack is found, do the inspections again at the times given in Paragraph 1.E., Compliance. f. Put the airplane back to a serviceable condition.Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 94 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT**

4. PART 4 - LOWER LOBE AREA AND SECTION 41 SKIN INSPECTION **NOTE:** Some areas of these inspections are also included in Boeing Service Bulletins 737-53- 1065, 737-53-1187 and 737-53-1168. The inspections given in this service bulletin do not replace the required inspections in Service Bulletins 737-53-1065, 737-53-1187 and 737-53-1168. However, operators may be able to receive credit for accomplishment of the Service Bulletin 737-53-1065, 737-53-1187 and 737-53-1168 inspections if the inspections given in this service bulletin satisfies the requirements of Service Bulletins 737-53-1065, 737-53-1187 and 737-53-1168. a. Gain access by removing the Wing - To - Body Fairing as required. Refer to 737-300/400/ 500 AMM 53-51-19, 737-300/400/500 AMM 53-51-20, 737-300/400/500 AMM 53-51-21 and 737-100/200 AMM 53-51-11, 737-100/200 AMM 53-51-21 as an accepted procedure. b. Group 1: (1) Do an external detailed inspection of the fuselage skin for any cracks as given in Figure 11. (a) If any crack is found, do one of the options that follow: 1) Option 1 - do the PERMANENT REPAIR as given in PART 5. {a} If the permanent repairs given in PART 5 are not applicable, contact Boeing for repair instructions and install the repair. 2) Option 2 - do the TIME-LIMITED REPAIR as given in PART 6, then inspect and replace at the times given in Paragraph 1.E., Compliance. {a} If the time-limited repair given in PART 6 is not applicable, then either do a permanent repair as given in Option 1 or contact Boeing for repair instructions and install the repair. (b) If no crack is found, do the inspections again at the times given in Paragraph 1.E., Compliance. c. Group 2: (1) Do an external detailed inspection of the fuselage skin for cracks as given in Figure 12. (a) If any crack is found, do one of the options that follow: 1) Option 1 - do the PERMANENT REPAIR as given in PART 5. {a} If the permanent repairs given in PART 5 are not applicable, contact Boeing for repair instructions and install the repair. 2) Option 2 - do the TIME-LIMITED REPAIR as given in PART 6, then inspect and replace at the times given in Paragraph 1.E., Compliance. {a} If the time-limited repair given in PART 6 is not applicable, then either do a permanent repair as given in Option 1 or contact Boeing for repair instructions and install the repair.Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 95 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT** (b) If no crack is found, do the inspections again at the times given in Paragraph 1.E., Compliance. d. Group 3: (1) Do an external detailed inspection of the fuselage skin for cracks as given in Figure 13. (2) Do an eddy current inspection of the fuselage skin for cracks at the locations as given in Figure 26. (3) If any crack is found in the above inspections, do one of the options that follow: (a) Option 1 - do the PERMANENT REPAIR as given in PART 5. 1) If the permanent repairs given in PART 5 are not applicable, contact Boeing for repair instructions and install the repair. (b) Option 2 - do the TIME-LIMITED REPAIR as given in PART 6, then inspect and replace at the times given in Paragraph 1.E., Compliance. 1) If the time-limited repair given in PART 6 is not applicable, then either do a permanent repair as given in Option 1 or contact Boeing for repair instructions and install the repair. (4) If no crack is found in the above inspections, do the inspections again at the times given in Paragraph 1.E., Compliance. e. Group 4, 11, 16: (1) Do an external detailed inspection of the fuselage skin for cracks as given in Figure 14. (2) Do an eddy current inspection of the fuselage skin for cracks at the locations as given in Figure 31. (3) If any crack is found in the above inspections, do one of the options that follow: (a) Option 1 - do the PERMANENT REPAIR as given in PART 5. 1) If the permanent repairs given in PART 5 are not applicable, contact Boeing for repair instructions and install the repair. (b) Option 2 - do the TIME-LIMITED REPAIR as given in PART 6, then inspect and replace at the times given in Paragraph 1.E., Compliance. 1) If the time-limited repair given in PART 6 is not applicable, then either do a permanent repair as given in Option 1 or contact Boeing for repair instructions and install the repair. (4) If no crack is found in the above inspections, do the inspections again at the times given in Paragraph 1.E., Compliance. f. Group 5, 12, 17, 19-20:Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 96 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT** (1) Do an external detailed inspection of the fuselage skin for cracks as given in Figure 15. (2) Do an eddy current inspection of the fuselage skin for cracks as given in Figure 27. (3) If any crack is found in the above inspections, do one of the options that follow: (a) Option 1 - do the PERMANENT REPAIR as given in PART 5. 1) If the permanent repairs given in PART 5 are not applicable, contact Boeing for repair instructions and install the repair. (b) Option 2 - do the TIME-LIMITED REPAIR as given in PART 6, then inspect and replace at the times given in Paragraph 1.E., Compliance. 1) If the time-limited repair given in PART 6 is not applicable, then either do a permanent repair as given in Option 1 or contact Boeing for repair instructions and install the repair. (4) If no crack is found in the above inspections, do the inspections again at the times given in Paragraph 1.E., Compliance. g. Group 9-10, 14-15, 18, 21: (1) Do an external detailed inspection of the fuselage skin for cracks as given in Figure 29. (2) Do an eddy current inspection of the fuselage skin for cracks at the locations as given in Figure 26. (3) If any crack is found in the above inspections, do one of the options that follow: (a) Option 1 - do the PERMANENT REPAIR as given in PART 5. 1) If the permanent repairs given in PART 5 are not applicable, contact Boeing for repair instructions and install the repair. (b) Option 2 - do the TIME-LIMITED REPAIR as given in PART 6, then inspect and replace at the times given in Paragraph 1.E., Compliance. 1) If the time-limited repair given in PART 6 is not applicable, then either do a permanent repair as given in Option 1 or contact Boeing for repair instructions and install the repair. (4) If no crack is found in the above inspections, do the inspections again at the times given in Paragraph 1.E., Compliance. h. Group 13: (1) Do an external detailed inspection of the fuselage skin for cracks as given in Figure 41. (a) If any crack is found, do one of the options that follow: 1) Option 1 - do the PERMANENT REPAIR as given in PART 5.Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 97 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT** {a} If the permanent repairs given in PART 5 are not applicable, contact Boeing for repair instructions and install the repair. 2) Option 2 - do the TIME-LIMITED REPAIR as given in PART 6, then inspect and replace at the times given in Paragraph 1.E., Compliance. {a} If the time-limited repair given in PART 6 is not applicable, then either do a permanent repair as given in Option 1 or contact Boeing for repair instructions and install the repair. (2) If no crack is found, do the inspections again at the times given in Paragraph 1.E., Compliance. i. Group 9-12, 15-18, 20: (1) Do an external detailed inspection of the fuselage skin for any crack between Station (STA) 259.5 and STA 360 as given in Figure 21. (a) If any crack is found, do one of the options that follow: 1) Option 1 - do the PERMANENT REPAIR as given in PART 5. {a} If the permanent repairs given in PART 5 are not applicable, contact Boeing for repair instructions and install the repair. 2) Option 2 - do the TIME-LIMITED REPAIR as given in PART 6, then inspect and replace at the times given in Paragraph 1.E., Compliance. {a} If the time-limited repair given in PART 6 is not applicable, then either do a permanent repair as given in Option 1 or contact Boeing for repair instructions and install the repair. (b) If no crack is found, do the inspections again at the times given in Paragraph 1.E., Compliance. j. Group 4-5, 13-14, 19, 21: (1) Do an external detailed inspection for any crack between STA 259.5 and STA 360 as given in Figure 22. (a) If any crack is found, do one of the options that follow: 1) Option 1 - do the PERMANENT REPAIR as given in PART 5. {a} If the permanent repairs given in PART 5 are not applicable, contact Boeing for repair instructions and install the repair. 2) Option 2 - do the TIME-LIMITED REPAIR as given in PART 6, then inspect and replace at the times given in Paragraph 1.E., Compliance. {a} If the time-limited repair given in PART 6 is not applicable, then either do a permanent repair as given in Option 1 or contact Boeing for repair instructions and install the repair.Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 98 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT** (b) If no crack is found, do the inspections again at the times given in Paragraph 1.E., Compliance. k. Group 1-5, 13-14, 19, 21: (1) Do an eddy current inspection for any crack at the stringer locations as given in Figure 28. (a) If any crack is found, do one of the options that follow: 1) Option 1 - do the PERMANENT REPAIR as given in PART 5. {a} If the permanent repairs given in PART 5 are not applicable, contact Boeing for repair instructions and install the repair. 2) Option 2 - do the TIME-LIMITED REPAIR as given in PART 6, then inspect and replace at the times given in Paragraph 1.E., Compliance. {a} If the time-limited repair given in PART 6 is not applicable, then either do a permanent repair as given in Option 1 or contact Boeing for repair instructions and install the repair. (b) If no crack is found, do the inspections again at the times given in Paragraph 1.E., Compliance. l. Group 6: (1) Do an external detailed inspection of the fuselage skin for any crack between Station (STA) 259.5 and STA 360 as given in Figure 21. (2) Do an external detailed inspection of the fuselage skin for cracks as given in Figure 29. (3) Do an eddy current inspection of the fuselage skin for cracks at the locations as given in Figure 26. (4) If any crack is found in the above inspections, do one of the options that follow: (a) Option 1 - do the PERMANENT REPAIR as given in PART 5. 1) If the permanent repairs given in PART 5 are not applicable, contact Boeing for repair instructions and install the repair. (b) Option 2 - do the TIME-LIMITED REPAIR as given in PART 6, then inspect and replace at the times given in Paragraph 1.E., Compliance. 1) If the time-limited repair given in PART 6 is not applicable, then either do a permanent repair as given in Option 1 or contact Boeing for repair instructions and install the repair. (5) If no crack is found in the above inspections, do the inspections again at the times given in Paragraph 1.E., Compliance. m. Group 7:Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 99 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT** (1) Do an external detailed inspection of the fuselage skin for cracks as given in Figure 14. (2) Do an external detailed inspection of the fuselage skin for any crack between Station (STA) 259.5 and STA 360 as given in Figure 21. (3) Do an eddy current inspection of the fuselage skin for cracks at the locations as given in Figure 31. (4) If any crack is found in the above inspections, do one of the options that follow: (a) Option 1 - do the PERMANENT REPAIR as given in PART 5. 1) If the permanent repairs given in PART 5 are not applicable, contact Boeing for repair instructions and install the repair. (b) Option 2 - do the TIME-LIMITED REPAIR as given in PART 6, then inspect and replace at the times given in Paragraph 1.E., Compliance. 1) If the time-limited repair given in PART 6 is not applicable, then either do a permanent repair as given in Option 1 or contact Boeing for repair instructions and install the repair. (5) If no crack is found in the above inspections, do the inspections again at the times given in Paragraph 1.E., Compliance. n. Group 8: (1) Do an external detailed inspection of the fuselage skin for cracks as given in Figure 15. (2) Do an external detailed inspection of the fuselage skin for any crack between Station (STA) 259.5 and STA 360 as given in Figure 21. (3) Do an eddy current inspection of the fuselage skin for cracks at the locations as given in Figure 27. (4) If any crack is found in the above inspections, do one of the options that follow: (a) Option 1 - do the PERMANENT REPAIR as given in PART 5. 1) If the permanent repairs given in PART 5 are not applicable, contact Boeing for repair instructions and install the repair. (b) Option 2 - do the TIME-LIMITED REPAIR as given in PART 6, then inspect and replace at the times given in Paragraph 1.E., Compliance. 1) If the time-limited repair given in PART 6 is not applicable, then either do a permanent repair as given in Option 1 or contact Boeing for repair instructions and install the repair. (5) If no crack is found in the above inspections, do the inspections again at the times given in Paragraph 1.E., Compliance.Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 100 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT** o. Install the Wing - To - Body Fairing as required and put the airplane back to a serviceable condition. 5. PART 5 - PERMANENT REPAIR a. Do a permanent repair as applicable as given in 737-100/200 SRM 53-30-3 Figure 48 or 737-300 SRM 53-00-01 Figure 201, Repair 31, or 737-400 SRM 53-00-01 Figure 201, Repair 31, or 737-500 SRM 53-00-01 Figure 201, Repair 31. b. Put the airplane back to a serviceable condition. 6. PART 6 - TIME-LIMITED REPAIR **NOTE:** The time-limited repairs apply to all groups of airplanes. However for Groups 6, 7 and 8 they only apply to the lower lobe below stringer 14, and section 41. a. Do one of the repairs that follow: (1) Repair chem-mill cracks found at lap splice. **CAUTION:** USE CAUTION WHEN LOCATING BLIND FASTENERS RELATIVE TO HIDDEN INTERNAL STRUCTURE. DRILLING INTO HIDDEN INTERNAL STRUCTURE OR EQUIPMENT, MAY RESULT IN DOWNTIME FOR EXPENSIVE REPAIR. (a) The repair that follows is subject to these limitations: **NOTE:** 1. Figure 17 should only be used for cracks at the chemically milled step in the upper skins at lap joints. 2. For a 10 inch wide tear strap spacing, this repair is limited to a crack with a maximum length of 5 inches, that is completely contained within the cutout shown in Figure 17. For smaller tear strap spacing, widths, the maximum crack length will be smaller. (Example: for a 9 inch wide tearstrap spacing, the maximum crack length is 4 inches). Do not use this repair in areas where the tearstrap spacing is greater than 10 inches. 3. Figure 17 repair is limited in size to one 10 inch tear strap bay, withthe crack completely contained in that bay. For cracks in multipleadjacent tearstrap bays repair as applicable as given in 737-100/200 SRM 53-30-3 Figure 48, or 737-300 SRM 53-00-01 Figure 201, Repair 31, or 737-400 SRM 53-00-01 Figure 201, Repair 31, or 737-500 SRM 53-00-01 Figure 201, Repair 31 or contact Boeing for repair instructions and install the repair. 4. Figure 17 repair can not be used in areas where existing bolts, Hi-Loks or lockbolts would be common to the repair. 5. Figure 17 repair can not be used in areas where existing fasteners are larger than 3/16 inch diameter.Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 101 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT** 6. Figure 17 repair can not be installed in an area where it would be common to a skin butt joint. 7. Figure 17 repair can not be used in door cutout bear strap locations. Contact Boeing for repair instructions and install the repair. 8. Figure 17 repairs can not be installed within 20 inches of an adjacent repair. 9. On airplanes line number 292 - 519, this repair can not be installed common to the window belt doubler at S-10 or S-14, between STA 360 and 540 or between STA 727 and 908. If the blind fasteners are installed in these areas, the insurance cut requirements of Boeing Service Bulletin 737-53-1178 can not be satisfied. 1) Install a time-limited skin repair as given in Figure 17. If the repair limits in the above note and in Figure 17 can not be maintained, then repair as applicable as given in 737-100/200 SRM 53-30-3 Figure 48, or 737-300 SRM 53-00-01 Figure 201, Repair 31, or 737-400 SRM 53-00-01 Figure 201, Repair 31, or 737-500 SRM 53-00-01 Figure 201, Repair 31 or contact Boeing for repair instructions and install the repair. 2) Put the airplane back to a serviceable condition. 3) Do an external detailed inspection of the repaired area for any cracks and loose, missing or damaged fasteners at the time given in paragraph 1.E., Compliance. {a} If any crack is found in the repaired area, contact Boeing for repair instructions and install the repair. {b} If any fastener is loose or missing or damaged, replace it with the same type and size of blind fastener. 4) Make the repair permanent at the time given in Paragraph 1.E., Compliance as follows: {a} Remove the following equipment from the passenger cabin as necessary for internal access to the area of the skin crack: **Equipment 737-200 AMM Subject 737-300/-400/-500 AMM Subject**  Passenger Seats 737-100/200 AMM 25-22-0 737-300/400/500 AMM 25-22-00 Sidewall Linings 737-100/200 AMM 25-21-311 737-300/400/500 AMM 25-21-46 Sidewall Insulation 737-100/200 AMM 25-21-347 737-300/400/500 AMM 25-21-39 Overhead Stowage Bins 737-100/200 AMM 25-24-311 737-300/400/500 AMM 25-24-31 Passenger Service Units 737-100/200 AMM 25-23-311 737-300/400/500 AMM 25-23-61 Ceiling Panels 737-100/200 AMM 25-21-341 737-300/400/500 AMM 25-21-45Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 102 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT CAUTION:**  USE CARE WHEN REMOVING FASTENERS. DO NOT DAMAGE THE HOLES. {b} Remove the time limited repair. {c} Do internal and external inspections of the repaired area for any cracks or delamination as given in Figure 18 and Figure 30. 1} If any crack or delamination is found in the repaired area, contact Boeing for repair instructions and install the repair. {d} Install the permanent repair as applicable as given in 737-100/200 SRM 53-30-3 Figure 48, or 737-300 SRM 53-00-01 Figure 201, Repair 31, or 737-400 SRM 53-00-01 Figure 201, Repair 31, or 737-500 SRM 53-00-01 Figure 201, Repair 31. **NOTE:** If a time limited repair was installed in accordance with the original issue, revision 1 or revision 2 of this service bulletin, then it is not required to stagger the fasteners common to the tear straps that were previously installed in the time limited repair. All new fasteners common to the tear straps in the permanent repair must be staggered as specified in the SRM. {e} Install the equipment in the passenger cabin that was removed for internal access. 5) Put the airplane back to a serviceable condition. (2) Repair Chem-mill cracks found at areas other than lap splice. **CAUTION:** USE CAUTION WHEN LOCATING BLIND FASTENERS RELATIVE TO HIDDEN INTERNAL STRUCTURE. DRILLING INTO HIDDEN INTERNAL STRUCTURE OR EQUIPMENT, MAY RESULT IN DOWNTIME FOR EXPENSIVE REPAIR. (a) For typical cracking in the skin at the chem-mill step, except at the lap splice, do the repairs as given in Figure 38. **NOTE:** Internal inspections of the tearstrap must also be done as given in Paragraph 1.E., Compliance. (b) Put the airplane back to a serviceable condition. (c) Do external detailed inspection of the repaired area for any cracks and loose, missing or damaged fasteners at the time given in Paragraph 1.E., Compliance. 1) If any crack is found in the repaired area contact Boeing for repair instructions and install the repair. 2) If any fastener is loose or missing or damaged, replace it with the same type and size of blind fastener.Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 103 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT** (d) Make the repair permanent at the time given in Paragraph 1.E., Compliance as follows: 1) Access the repair area as follows: — Remove the passenger seats. Refer to 737-300/400/500 AMM 25-22-00 as an accepted procedure. — Remove the passenger carpets. Refer to 737-300/400/500 AMM 25-27-15 as an accepted procedure. — Remove the passenger cabin sidewall panels. Refer to 737-300/400/ 500 AMM 25-21-46 as an accepted procedure. — Remove the passenger cabin sidewall insulation blankets. Refer to 737-300/400/500 AMM 25-21-39 as an accepted procedure. — Remove the aft cargo compartment sidewall panels and insulation blankets. Refer to 737-300/400/500 AMM 25-52-73 as an accepted procedure. 2) Remove the time limited repair. 3) Inspect the tearstrap internally as given in Figure 30. 4) Install the permanent repair as applicable as given in 737-100/200 SRM 53-30-3 Figure 48, or 737-300 SRM 53-00-01 Figure 201, Repair 31, or 737-400 SRM 53-00-01 Figure 201, Repair 31, or 737-500 SRM 53-00-01 Figure 201, Repair 31. 5) Install the furnishings that were removed for access: — Install the aft cargo compartment sidewall panels and insulation blankets. Refer to 737-300/400/500 AMM 25-52-73 as an accepted procedure. — Install the passenger cabin sidewall insulation blankets. Refer to 737-300/400/500 AMM 25-21-39 as an accepted procedure. — Install the passenger cabin sidewall panels. Refer to 737-300/400/500 AMM 25-21-46 as an accepted procedure. — Install the passenger carpets. Refer to 737-300/400/500 AMM 25-27-15 as an accepted procedure. — Install the passenger seats. Refer to 737-300/400/500 AMM 25-22-00 as an accepted procedure. (e) Put the airplane back to a serviceable condition. 7. Group 3, 5, 9-10, 12, 14-15, 17-21: PART 7 - PREVENTIVE MODIFICATION a. The preventive modification is subject to these limitations: (1) This preventive modification is applicable only to Group 3, 5, 9, 10, 12, 14-15, 17-21 airplanes. (2) This preventive modification should only be used at the chem-milled pockets in the upper skins at S-12 between STA 500D to STA 520 for 737-300 and STA 482B to STA 520 for 737-500 airplanes. (3) The preventive modification can not be used in areas where existing bolts, Hi-Loks or lockbolts can be common to the modification.Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 104 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT** b. Remove the following equipment from the passenger cabin as necessary for internal access to the area of the skin modification:

c. Install the preventive modification as given in Figure 10. d. Install the equipment in the passenger cabin that was removed for internal access. e. Put the airplane back to a serviceable condition. f. Do the inspections in PART 2 again at the times as given in Paragraph 1.E., Compliance. 8. Group 3, 5, 9-10, 12, 14-15, 17-21: PART 8 - SKIN CHEM-MILL LINE CRACK AT STRINGER 12 - REPAIR INSTRUCTIONS AND POST REPAIR INSPECTION a. REPAIR INSTRUCTIONS - SKIN CHEM-MILL LINE CRACK AT STRINGER 12 (1) Do the stringer 12 repair as given in Figure 24. (2) Put the airplane back to a serviceable condition. b. POST REPAIR INSPECTION - SKIN CHEM-MILL CRACK REPAIR AT STRINGER 12 (1) Do post repair inspection of the skin chem-mill crack repair at stringer 12 as given in Figure 48. **Equipment 737-300/-400/-500 AMM Subject** Passenger Seats 737-300/400/500 AMM 25-22-00 Sidewall Linings 737-300/400/500 AMM 25-21-46 Sidewall Insulation 737-300/400/500 AMM 25-21-39 Overhead Stowage Bins 737-300/400/500 AMM 25-24-31 Passenger Service Units 737-300/400/500 AMM 25-23-61 Ceiling Panels 737-300/400/500 AMM 25-21-45**FIGURE 1: THIS FIGURE WAS DELETED AT REVISION 2** Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 105 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT FIGURE 1: THIS FIGURE WAS DELETED AT REVISION 2** 

THIS FIGURE IS DELETED. COMPLIANCE INFORMATION MOVED TO PARAGRAPH 1.E.1840387

**(SHEET 1 OF 1) FIGURE 2: THIS FIGURE**  **WAS DELETED AT REVISION 2** Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 106 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT FIGURE 2: THIS FIGURE WAS DELETED AT REVISION 2** 

THIS FIGURE IS DELETED. COMPLIANCE INFORMATION MOVED TO PARAGRAPH 1.E.1840388

**(SHEET 1 OF 1) FIGURE 3: SKIN INSPECTIONS IN THE CROWN AREA AND OTHER AREAS OF KNOWN CRACKING**  Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 107 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT FIGURE 3: SKIN INSPECTIONS IN THE CROWN AREA AND OTHER AREAS OF KNOWN CRACKING** 

B SEE 2

1 B SEE 2

1 2 1 A SEE

2 1 C SEE

C SEE 3 727A+10

737-200C AIRPLANE TYPICAL STA

480 STA

500 STA 500A STA 380 STA

360 STA 928 STA
STA 908 FOR TYPICAL INSPECTION AREA

STA 727 INSPECT ALONG ALL OF THE LAP JOINTS SHOWN IN BOLD LINES

S-10L S-14L
S-20L S-25L S-10R S-14R

S-4R

S-4L S-14R S-10R

S-14L S-10L S-4R

S-4L 259.50

STA 540 STA STA 1016 STA 1006V21665

**(SHEET 1 OF 5) FIGURE 3: SKIN INSPECTIONS IN THE CROWN AREA AND OTHER AREAS OF KNOWN CRACKING**  Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 108 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT**

SKIN UPPER CRACK TYPICAL

INSPECTION AREA LOWER SKIN DOUBLER UPPER CRACK TYPICAL



### A 2 1 INSPECTION AREA TYPICAL 

### A

A

LOWER SKIN UPPER SKIN

INBD UP FRAME

C/L

10.00 3

STRINGER CRACK



### A-A STRINGER C/LV21671

**(SHEET 2 OF 5) FIGURE 3: SKIN INSPECTIONS IN THE CROWN AREA AND OTHER AREAS OF KNOWN CRACKING**  Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 109 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT**

INSPECTION AREA FWD CRACKS TYPICAL STA 540 STA 520

S-16 S-15 S-14

TYPICAL CRACKS TYPICAL CRACKS TYPICAL CRACKS



### B 1 2 1 2V27370

**(SHEET 3 OF 5) FIGURE 3: SKIN INSPECTIONS IN THE CROWN AREA AND OTHER AREAS OF KNOWN CRACKING**  Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 110 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT**

This Figure applies to Group 1: The step numbers shown below agree with the numbers shown in the circle symbols in the figure. **NOTE:** The crown area inspections that follow are not necessary at lap joint locations that have been modified as given in Revision 4, 5 or 6 of Boeing Service Bulletin 737-53A1177. **STEP TASK NAME IDENTIFICATION QTY MORE DATA** 1 Inspect Fuselage Skin - - (a) 2 Inspect Fuselage Skin - - (b) 3 Inspect Fuselage Skin - - (c) INSPECTION AREA STA 927 STA 918.12 STA 908

S-9

S-10

CHEM-MILLED STEP IS HIGHER THAN NORMAL AT THIS LOCATION TYPICAL CRACK

FWD TYPICAL CRACK



### C 1 2 31484830

**(SHEET 4 OF 5) FIGURE 3: SKIN INSPECTIONS IN THE CROWN AREA AND OTHER AREAS OF KNOWN CRACKING**  Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 111 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT**

(a) Do an external detailed inspection of the fuselage skin for chem-mill cracks. (b) Do an external eddy current inspection for chem-mill cracks as given in 737 NDT, Part 6, 53-30-09 or 737 NDT, Part 6, 53-30-18 or 737 NDT, Part 6, 53-30-19 or 737 NDT, Part 6, 53-30-25. (c) Do a detailed or general visual inspection of the non-lap-splice areas between STA 360 to STA 1016 and S-10L to S-10R for horizontal chem-mill cracks. If general visual inspections are accomplished in lieu of detailed inspections, then repeat inspection intervals are reduced as given in Paragraph 1.E., Compliance.

**STEP TASK NAME IDENTIFICATION QTY MORE DATA**

**(SHEET 5 OF 5) FIGURE 4: SKIN INSPECTIONS IN THE CROWN AREA AND OTHER AREAS OF KNOWN CRACKING**  Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 112 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT FIGURE 4: SKIN INSPECTIONS IN THE CROWN AREA AND OTHER AREAS OF KNOWN CRACKING** 

1 2 1 2 A SEE

B SEE

B SEE 2 1 3 2 1

C SEE

C

SEE STA 727A+10 INSPECTION AREA FOR TYPICAL INSPECT ALONG ALL OF THE LAP

S-10L S-14L
S-20L S-25L S-10R S-14R

S-4R

S-4L STA 928

737-200 AIRPLANE TYPICAL JOINTS SHOWN IN BOLD LINES

S-14R S-10R

S-14L S-10L S-4R

S-4L 259.50

STA 360 STA 540 STA STA 727 STA 908 STA 1016 587 STA 633 STA

STA 1006V21669

**(SHEET 1 OF 5) FIGURE 4: SKIN INSPECTIONS IN THE CROWN AREA AND OTHER AREAS OF KNOWN CRACKING**  Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 113 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT**

UPPER DOUBLER

SKIN LOWER

INSPECTION AREA TYPICAL CRACK

UPPER SKIN TYPICAL CRACK

1 2



### A 3

10.00 C/L FRAME

UP
INBD SKIN UPPER

SKIN LOWER 

### A A

TYPICAL

AREA INSPECTION

CRACK C/L STRINGER



### A-A STRINGERV21672

**(SHEET 2 OF 5) FIGURE 4: SKIN INSPECTIONS IN THE CROWN AREA AND OTHER AREAS OF KNOWN CRACKING**  Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 114 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT**

INSPECTION AREA FWD CRACKS TYPICAL STA 540 STA 520

S-16 S-15 S-14

TYPICAL CRACKS TYPICAL CRACKS TYPICAL CRACKS



### B 1 2 1 2V27371

**(SHEET 3 OF 5) FIGURE 4: SKIN INSPECTIONS IN THE CROWN AREA AND OTHER AREAS OF KNOWN CRACKING**  Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 115 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT**

This Figure applies to Group 2, 13: The step numbers shown below agree with the numbers shown in the circle symbols in the figure. **NOTE:** The crown area inspections that follow are not necessary at lap joint locations that have been modified as given in Revision 4, 5 or 6 of Boeing Service Bulletin 737-53A1177. **STEP TASK NAME IDENTIFICATION QTY MORE DATA** 1 Inspect Fuselage Skin - - (a) 2 Inspect Fuselage Skin - - (b) 3 Inspect Fuselage Skin - - (c) INSPECTION AREA STA 927 STA 918.12 STA 908

S-9

S-10

CHEM-MILLED STEP IS HIGHER THAN NORMAL AT THIS LOCATION UPPER SKIN

TYPICAL CRACK FWD TYPICAL CRACK



### C 1 2 31484831

**(SHEET 4 OF 5) FIGURE 4: SKIN INSPECTIONS IN THE CROWN AREA AND OTHER AREAS OF KNOWN CRACKING**  Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 116 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT**

(a) Do an external detailed inspection of the fuselage skin for chem-mill cracks. (b) Do an external eddy current inspection for chem-mill cracks as given in 737 NDT, Part 6, 53-30-09 or 737 NDT, Part 6, 53-30-18 or 737 NDT, Part 6, 53-30-19 or 737 NDT, Part 6, 53-30-25. (c) Do a detailed or general visual inspection of the non-lap-splice areas between STA 360 to STA 1016 and S-10L to S-10R for horizontal chem-mill cracks. If general visual inspections are accomplished in lieu of detailed inspections, then repeat inspection intervals are reduced as given in Paragraph 1.E., Compliance.

**STEP TASK NAME IDENTIFICATION QTY MORE DATA**

**(SHEET 5 OF 5) FIGURE 5: CROWN AREA SKIN INSPECTIONS**  Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 117 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT FIGURE 5: CROWN AREA SKIN INSPECTIONS** 



### 737-300 AIRPLANES RIGHT SIDE OPPOSITE LEFT SIDE SHOWN 1 3 2 A SEE

FWD 727A+10 STA

727 STA 928 STA

908 STA

S-14L S-10L S-4L S-14L S-10L

S-4R

540 STA BL 0 1016 STA S-4R

BL S-4L 0

360 STA 540 STA

INSPECTION AREA FOR TYPICAL

587 STA 664 STAV21730

**(SHEET 1 OF 3) FIGURE 5: CROWN AREA SKIN INSPECTIONS**  Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 118 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT**

This Figure applies to Group 3, 9-10, 14-15: 

### UPPER DOUBLER

SKIN LOWER

INSPECTION AREA TYPICAL CRACK

UPPER SKIN TYPICAL CRACK

1 2



### A 3

10.00 C/L FRAME

UP
INBD SKIN UPPER

SKIN LOWER 

### A A

TYPICAL

AREA INSPECTION C/L STRINGER



### A-A CRACK

STRINGERV21734

**(SHEET 2 OF 3) FIGURE 5: CROWN AREA SKIN INSPECTIONS**  Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 119 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT** The step numbers shown below agree with the numbers shown in the circle symbols in the figure. **NOTE:** The crown area inspections that follow are not necessary at lap joint locations that have been modified as given in Revision 4, 5 or 6 of Boeing Service Bulletin 737-53A1177. **STEP TASK NAME IDENTIFICATION QTY MORE DATA** 1 Inspect Fuselage Skin - - (a) 2 Inspect Fuselage Skin - - (b) 3 Inspect Fuselage Skin - - (c) (a) Do an external detailed inspection of the fuselage skin for chem-mill cracks. (b) Do an external eddy current inspection for chem-mill cracks as given in 737 NDT, Part 6, 53-30-09 or 737 NDT, Part 6, 53-30-18 or 737 NDT, Part 6, 53-30-19 or 737 NDT, Part 6, 53-30-25. (c) Do a detailed or general visual inspection of the non-lap-splice areas between STA 360 to STA 1016 and S-10L to S-10R for horizontal chem-mill cracks. If general visual inspections are accomplished in lieu of detailed inspections, then repeat inspection intervals are reduced as given in Paragraph 1.E., Compliance.

**(SHEET 3 OF 3) FIGURE 6: CROWN AREA SKIN INSPECTIONS**  Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 120 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT FIGURE 6: CROWN AREA SKIN INSPECTIONS** 

737-400 AIRPLANES RIGHT SIDE OPPOSITE LEFT SIDE SHOWN A SEE

3 1 2

FWD 928 STA

STA 908

727A+10 STA
STA 727 S-4L

S-10L S-14L FOR TYPICAL INSPECTION AREA STA 1016

STA 540

STA 360 S-4L S-4R

0 BL 540 STA

S-4R

0 BL S-10L
S-14L

550 STA 653 STAV21736

**(SHEET 1 OF 3) FIGURE 6: CROWN AREA SKIN INSPECTIONS**  Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 121 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT**

This Figure applies to Group 4, 11, 16: 

### UPPER DOUBLER

SKIN LOWER

INSPECTION AREA TYPICAL CRACK

UPPER SKIN TYPICAL CRACK



### A 1 2 3

AREA INSPECTION LAP JOINT TYPICAL 10.00 C/L FRAME

UP
INBD SKIN UPPER

SKIN LOWER 

### A A

C/L STRINGER



### A-A CRACK

STRINGERV21737

**(SHEET 2 OF 3) FIGURE 6: CROWN AREA SKIN INSPECTIONS**  Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 122 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT** The step numbers shown below agree with the numbers shown in the circle symbols in the figure. **STEP TASK NAME IDENTIFICATION QTY MORE DATA** 1 Inspect Fuselage Skin - - (a) 2 Inspect Fuselage Skin - - (b) 3 Inspect Fuselage Skin - - (c) (a) Do an external detailed inspection of the fuselage skin for chem-mill cracks. (b) Do an external eddy current inspection for chem-mill cracks as given in 737 NDT, Part 6, 53-30-09 or 737 NDT, Part 6, 53-30-18 or 737 NDT, Part 6, 53-30-19 or 737 NDT, Part 6, 53-30-25. (c) Do a detailed or general visual inspection of the non-lap-splice areas between STA 360 to STA 1016 and S-10L to S-10R for horizontal chem-mill cracks. If general visual inspections are accomplished in lieu of detailed inspections, then repeat inspection intervals are reduced as given in Paragraph 1.E., Compliance.

**(SHEET 3 OF 3) FIGURE 7: CROWN AREA SKIN INSPECTIONS**  Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 123 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT FIGURE 7: CROWN AREA SKIN INSPECTIONS** 



### 737-500 AIRPLANES RIGHT SIDE OPPOSITE LEFT SIDE SHOWN A SEE

3 1 2

1 2
FWD STA 928

727A+10 STA FOR TYPICAL INSPECTION AREA STA 540

STA 360 0 S-4L BL S-4R

STA STA

908 1016
0 BL

STA

STA 540 727 S-4R S-10L

S-14L

S-4L

S-10L S-14L

587 STA 664 STA STA 727CV21738

**(SHEET 1 OF 3) FIGURE 7: CROWN AREA SKIN INSPECTIONS**  Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 124 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT**

This Figure applies to Group 5, 12, 17: 

### UPPER DOUBLER

SKIN LOWER

INSPECTION AREA TYPICAL CRACK

UPPER SKIN TYPICAL CRACK



### A 1 2 3

TYPICAL LAP JOINT
AREA INSPECTION 10.00 C/L FRAME

UP
INBD SKIN UPPER

SKIN LOWER 

### A A

C/L STRINGER



### A-A CRACK

STRINGERV21739

**(SHEET 2 OF 3) FIGURE 7: CROWN AREA SKIN INSPECTIONS**  Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 125 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT** The step numbers shown below agree with the numbers shown in the circle symbols in the figure. **STEP TASK NAME IDENTIFICATION QTY MORE DATA** 1 Inspect Fuselage Skin - - (a) 2 Inspect Fuselage Skin - - (b) 3 Inspect Fuselage Skin - - (c) (a) Do an external detailed inspection of the fuselage skin for chem-mill cracks. (b) Do an external eddy current inspection for chem-mill cracks as given in 737 NDT, Part 6, 53-30-09 or 737 NDT, Part 6, 53-30-18 or 737 NDT, Part 6, 53-30-19 or 737 NDT, Part 6, 53-30-25. (c) Do a detailed or general visual inspection of the non-lap-splice areas between STA 360 to STA 1016 and S-10L to S-10R for horizontal chem-mill cracks. If general visual inspections are accomplished in lieu of detailed inspections, then repeat inspection intervals are reduced as given in Paragraph 1.E., Compliance.

**(SHEET 3 OF 3) FIGURE 8: THIS FIGURE**  **WAS DELETED AT REVISION 2** Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 126 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT FIGURE 8: THIS FIGURE WAS DELETED AT REVISION 2** 

THIS FIGURE IS DELETED. .1553909

**(SHEET 1 OF 1) FIGURE 9: THIS FIGURE WAS DELETED AT REVISION 2**  Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 127 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT FIGURE 9: THIS FIGURE WAS DELETED AT REVISION 2** 

THIS FIGURE IS DELETED. .1553909

**(SHEET 1 OF 1) FIGURE 10: PREVENTIVE MODIFICATION**  Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 128 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT FIGURE 10: PREVENTIVE MODIFICATION** 

737-300 AND 737-500 AIRPLANES AND INSTALLATION FABRICATION FOR PART

AND FASTENER REMOVAL INSPECTION AREA FOR TYPICAL

RIGHT SIDE OPPOSITE LEFT SIDE SHOWN B SEE

A SEE 540 S-4R

S-14L S-10L BL 0 S-4L

360 STA STA

FWDV58074

**(SHEET 1 OF 7) FIGURE 10: PREVENTIVE MODIFICATION**  Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 129 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT**

INSPECTION AREA TYPICAL CRACK 500D+10 737-300 500D 737-300 482B 737-500 STA
STA 482B+10 737-500 STA
STA STA 520

S-12

FWD



### VIEW LOOKING INBOARD 3



### A 4

4 5 1

1 2 2 1 2

1 2V58075

**(SHEET 2 OF 7) FIGURE 10: PREVENTIVE MODIFICATION**  Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 130 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT**

VIEW LOOKING OUTBOARD I I I

I I I I I I I I I I

I I I

I I
I I

I I I

I I I

I

I I I I I I

I

I I

I I I I I

I I

I I I I I I I I I I I I I I I I I I I

I I

I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I

I I I

I I I I I I

I I

I

1.00 (TYPICAL)

21 EQUAL SPACES 0.75 (TYPICAL)

18 EQUAL SPACES

C S-13 S-11

A A

B C B 500D 737-300 500D+10 737-300 520 STA 482B+10 737-500 STA STA 482B 737-500 STA STA

S-12

FWD 10 9

7 13



### B 10 8 17

16 14 10 6 10 9 10 7

10 9 10

9 11 13 11

15

11

10 11 12 C C C C C C C C C C C C C C C C C C C C C C C

C C C

C C

C C C C

C C C C C C C C

C C C C

C C
C C C C C

C C C

C C C

C C

C C

C

C C C

C C

C C

C C C C

CV58264

**(SHEET 3 OF 7) FIGURE 10: PREVENTIVE MODIFICATION**  Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 131 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT**

This Figure applies to Group 3, 5, 9-10, 12, 14-15, 17-21: 

### SKIN S-12

BONDED DOUBLER FILLER

FILLER POCKET DOUBLER INTERNAL

TAPERED SHIM FRAME SKIN SKIN

DOUBLER BONDED DOUBLER BONDED

INTERNAL DOUBLER INTERNAL DOUBLER FILLER POCKET S-12 S-11

S-13 S-11

S-12

S-13

TAPERED SHIM FWD 

### A-A 12

13 14

11 14 14 13 11



### C-C B-BV62813

**(SHEET 4 OF 7) FIGURE 10: PREVENTIVE MODIFICATION**  Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 132 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT** The step numbers shown below agree with the numbers shown in the circle symbols in the figure. **NOTE:** 1. This modification cannot be used in areas where bolts, hi-locks or lockbolts were installed in production. 2. Install fasteners using the fastener pattern that exists and this figure as a guide to determine fastener pitch. Make the new fasteners spacing 1.5 to 2.0 inch. Maintain a minimum edge margin of two times the fastener diameter for new fastener locations and 1.7 times the fastener diameter for fastener locations that exist. 3. In the typical modification shown in this figure may be different, depending on the specific location. Use this figure as a guide, maintaining the same number and pattern of fasteners around the preventive modification, and common to the tear straps or shear ties. INSPECTION

FASTENER REMOVAL

PART FABRICATION **NOTE:** 1. Size the repair parts to maintain a minimum edge margin of two times the fastener diameter at new fastener locations, and of 1.7 times the fastener diameter at existing fastener locations. 2. Maintain a minimum corner radius of 0.5 inch unless specified differently in the figure. **STEP TASK NAME IDENTIFICATION QTY MORE DATA** 1 Inspect Fuselage Skin - - (a) 2 Inspect Fuselage Skin - - (b)(c)

**STEP TASK NAME IDENTIFICATION QTY MORE DATA**
3 Remove Fasteners - - In the area that will be common to the preventive modification.
4 Inspect Fastener Holes - - Common to the preventive modification (d) 5 Inspect Fuselage Skin - - (e)

**STEP TASK NAME IDENTIFICATION QTY MORE DATA** 6 Make Internal Doubler “A” 2024-T3 clad sheet 1 0.032 inch thick (f) 7 Make Pocket Filler “B” 2024-T3 clad sheet 4 0.040 inch thick (f) 8 Make Filler “C” under S-12 2024-T3 clad sheet 1 0.032 inch thick (f)

**(SHEET 5 OF 7) FIGURE 10: PREVENTIVE MODIFICATION**  Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 133 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT**

INSTALLATION **NOTE:** 1. Shim under shear ties, stringers and all gaps from 0.01 - 0.032 inch prior to fastener installation. Contact Boeing for instructions for gaps greater than 0.032 inch. 2. Clean the faying surfaces of the fuselage skin and modification parts prior to the application of sealant. Refer to SOPM 20-50-19 as an accepted procedure. 9 Make Tapered Shim “D” BAC 1534 8 0.032 to 0.010 inch with 100:1 taper.

10 Apply Chemical Film Treatment Alodine or Iridite - -
Primer BMS 10-79 TYPE II - 1 coat.

**STEP TASK NAME IDENTIFICATION QTY MORE DATA**

11 Install Tapered Shim “D” 8 With BMS 5-95 faying surface sealant. 12 Install Filler, under S-12 “C” 1 With BMS 5-95 faying surface sealant. 13 Install Pocket Filler “B” 4 With BMS 5-95 faying surface sealant. 14 Install Internal Doubler “A” 1 With BMS 5-95 faying surface sealant.
15 Apply Fillet Seal - - Use BMS 5-95 sealant around the edges of the repair parts 16 Apply Finish - - To the repaired area to match adjacent structure.
17 Apply Organic Corrosion Inhibitor - - Use BMS 3-23 to the internal surfaces of the repaired area. (a) Do a detailed inspection using a bright light and a 10X magnifying glass of the surface of the skin panels for skin cracks. (b) Do a subsurface Eddy Current inspection or Magneto Optical Imaging (MOI) inspection for subsurface skin cracks along the edge of the bonded doubler. Inspect in areas as given in Paragraph 1.E. Compliance. Do the MFEC Inspection as given in 737 NDT, Part 6, 53-30-09 or 737 NDT, Part 6, 53-30-18 or do the Magneto Optical Imaging (MOI) inspection as given in 737 NDT, Part 6, 53-30-19 or do the C-Scan inspection as given in 737 NDT, Part 6, 53-30-25. (c) If external eddy current inspections can not be accomplished because of interference with external doublers or other interferences, internal eddy current inspection as given in 737 NDT, Part 6, 53-30-20 may be substituted. Do not substitute external inspections for internal unless external inspections are not possible. **STEP TASK NAME IDENTIFICATION QTY MORE DATA**

**(SHEET 6 OF 7) FIGURE 10: PREVENTIVE MODIFICATION**  Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 134 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT**

The codes shown below agree with the letter shown in the upper left corner of the fastener symbols in the figure. A number in the lower right corner gives the grip length of the fastener. If the grip length shown is not available at Boeing, fasteners supplied in kits may be one grip length longer than indicated. Also, if any of the fastener part numbers are not available or have been superseded, substitute fasteners may be supplied in Boeing kits, Boeing Document D-590 and Boeing drawing 65-88700 are used to determine the part numbers used as substitutes.

(d) Use 737 NDT, Part 6, 51-00-00, Figure 16 with .03 notch standard and 737 NDT, Part 6, 51-30-00, Figure 3. If cracks are found, contact Boeing. If no cracks are found, it is not necessary to make the holes oversize. (e) Do a detailed inspection of the skin in the area of the modification for corrosion or disbonded doublers. Look for bulging, white powder, or a thin black line. If corrosion or disbond is found, contact Boeing. If no corrosion or disbond is found, continue with the modification. (f) Pre-form to the contour of the fuselage.

**CODE NAME IDENTIFICATION HOLE DIA MORE DATA** C Rivet BACR15BB5D( ) 0.159 - 0.171 (a) I Rivet BACR15CE6D( ) 0.190 - 0.196 (b) (a) The minimum diameter of the driven head of the rivet is 1.4 times the fastener diameter. (b) Maintain a minimum edge margin at the shear tie of 1.5 times the fastener diameter. If this edge margin cannot be maintained, contact Boeing. **STEP TASK NAME IDENTIFICATION QTY MORE DATA**



### EXAMPLE OF FASTENER SYMBOL FASTENER LENGTH/GRIP FASTENER

D 6F
7 LETTER CODE DIAMETER (OPTIONAL) HEAD LOCATION N = NEAR SIDE F = FAR SIDE (OPTIONAL)

(OPTIONAL)V77720

**(SHEET 7 OF 7) FIGURE 11: SKIN INSPECTIONS IN THE LOWER LOBE AREA AND IN SECTION 41**  Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 135 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT FIGURE 11: SKIN INSPECTIONS IN THE LOWER LOBE AREA AND IN SECTION 41** 

TYPICAL INSPECTION AREA SEE A SEE A

737-200C AIRPLANES 1016 STA 908 STA 727 STA STA 540 STA 360 STA 259.50

S-4L S-4R S-19R S-26R

BL 0 BL 0

S-10L S-14L
S-19L
S-24L S-10R S-14R S-19R

S-4L S-4R S-14R S-20R S-25R

S-10R

S-25L S-20L S-14L S-10L S-24R

S-19L

S-26LV21775

**(SHEET 1 OF 3) FIGURE 11: SKIN INSPECTIONS IN THE LOWER LOBE AREA AND IN SECTION 41**  Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 136 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT**

This Figure applies to Group 1: CRACKS TYPICAL

SKIN LOWER TYPICAL CRACK UPPER DOUBLER UPPER SKIN



### A C/L FRAME

1

INSPECTION

TYPICAL

AREA 1

C/L STRINGERV32393

**(SHEET 2 OF 3) FIGURE 11: SKIN INSPECTIONS IN THE LOWER LOBE AREA AND IN SECTION 41**  Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 137 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT**
The step numbers shown below agree with the numbers shown in the circle symbols in the figure. **STEP TASK NAME IDENTIFICATION QTY MORE DATA** 1 Inspect Fuselage Skin - - (a) (a) Do a detailed or general visual inspection for chem-mill cracks. If general visual inspections are accomplished in lieu of detailed inspections, then repeat inspection intervals are reduced as given in Paragraph 1.E., Compliance.

**(SHEET 3 OF 3) FIGURE 12: SKIN INSPECTIONS IN**  **THE LOWER LOBE AREA AND IN SECTION 41** Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 138 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT FIGURE 12: SKIN INSPECTIONS IN TH**  **E LOWER LOBE AREA AND IN SECTION 41**

S-4L S-4R S-19R S-26R 1016 STA 908 STA 727 STA STA STA 360 STA 259.50 540

BL 0 BL 0

S-25L S-20L S-14L S-10L S-10R S-14R S-20R

S-4L
S-10L S-14L
S-19L
S-24L

S-4R S-10R S-14R S-19R S-24R S-25R

737-200 AIRPLANE S-26R S-19R

INSPECTION AREA SEE A

SEE A TYPICALV21780

**(SHEET 1 OF 3) FIGURE 12: SKIN INSPECTIONS IN**  **THE LOWER LOBE AREA AND IN SECTION 41** Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 139 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT**

This Figure applies to Group 2: CRACKS TYPICAL

SKIN LOWER TYPICAL CRACK UPPER DOUBLER UPPER SKIN



### A C/L FRAME

1

INSPECTION

TYPICAL

AREA 1

C/L STRINGERV32394

**(SHEET 2 OF 3) FIGURE 12: SKIN INSPECTIONS IN**  **THE LOWER LOBE AREA AND IN SECTION 41** Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 140 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT**
The step numbers shown below agree with the numbers shown in the circle symbols in the figure. **STEP TASK NAME IDENTIFICATION QTY MORE DATA** 1 Inspect Fuselage Skin - - (a) (a) Do a detailed or general visual inspection for chem-mill cracks. If general visual inspections are accomplished in lieu of detailed inspections, then repeat inspection intervals are reduced as given in Paragraph 1.E., Compliance.

**(SHEET 3 OF 3) FIGURE 13: SKIN INSPECTIONS IN**  **THE LOWER LOBE AREA AND IN SECTION 41** Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 141 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT FIGURE 13: SKIN INSPECTIONS IN THE LOWER LOBE AREA AND IN SECTION 41** 

259.50

STA 360 STA 540 STA STA 727 STA 908 STA 1016

S-26R

S-19R S-25R S-24R
S-19R
S-14R

S-24L S-19L S-14L S-20R
S-14R

S-14L
S-20L S-25L BL 0

BL 0

737-300 AIRPLANE TYPICAL INSPECTION AREA SEE A

SEE AV21812

**(SHEET 1 OF 3) FIGURE 13: SKIN INSPECTIONS IN**  **THE LOWER LOBE AREA AND IN SECTION 41** Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 142 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT**

This Figure applies to Group 3: CRACKS TYPICAL

SKIN LOWER TYPICAL CRACK UPPER DOUBLER UPPER SKIN



### A C/L FRAME

1

INSPECTION

TYPICAL

AREA 1

C/L STRINGERV32395

**(SHEET 2 OF 3) FIGURE 13: SKIN INSPECTIONS IN**  **THE LOWER LOBE AREA AND IN SECTION 41** Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 143 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT**
The step numbers shown below agree with the numbers shown in the circle symbols in the figure. **STEP TASK NAME IDENTIFICATION QTY MORE DATA** 1 Inspect Fuselage Skin - - (a) (a) Do a detailed or general visual inspection for chem-mill cracks. If general visual inspections are accomplished in lieu of detailed inspections, then repeat inspection intervals are reduced as given in Paragraph 1.E., Compliance.

**(SHEET 3 OF 3) FIGURE 14: SKIN INSPECTIONS IN THE LOWER LOBE AREA**  Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 144 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT FIGURE 14: SKIN INSPECTIONS IN THE LOWER LOBE AREA** 

RIGHT SIDE OPPOSITE LEFT SIDE SHOWN STA 540

1016 STA STA 540 RIGHT SIDE SHOWN LEFT SIDE OPPOSITE (EXCEPT AS NOTED)

INSPECTION AREA 907 STA 727 STA

727G STA (RIGHT SIDE ONLY) CARGO DOOR CUTOUT

BL 0

S-25R S-25L S-20L S-14L S-10L 360 STA

B SEE B SEE

UP FWD UP FWD S-26R S-19R S-10R

S-14R

S-26LV21779

**(SHEET 1 OF 3) FIGURE 14: SKIN INSPECTIONS IN THE LOWER LOBE AREA**  Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 145 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT**

This Figure applies to Group 4, 7, 11, 16: CRACKS TYPICAL

SKIN LOWER TYPICAL CRACK UPPER DOUBLER UPPER SKIN



### B C/L FRAME

1

INSPECTION

TYPICAL

AREA 1

C/L STRINGERV32399

**(SHEET 2 OF 3) FIGURE 14: SKIN INSPECTIONS IN THE LOWER LOBE AREA**  Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 146 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT**
The step numbers shown below agree with the numbers shown in the circle symbols in the figure. **STEP TASK NAME IDENTIFICATION QTY MORE DATA** 1 Inspect Fuselage Skin - - (a) (a) Do a detailed or general visual inspection for chem-mill cracks. If general visual inspections are accomplished in lieu of detailed inspections, then repeat inspection intervals are reduced as given in Paragraph 1.E., Compliance.

**(SHEET 3 OF 3) FIGURE 15: SKIN INSPECTIONS IN THE LOWER LOBE AREA**  Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 147 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT FIGURE 15: SKIN INSPECTIONS IN THE LOWER LOBE AREA** 



### (EXCEPT AS NOTED) LEFT SIDE OPPOSITE RIGHT SIDE SHOWN

RIGHT SIDE OPPOSITE LEFT SIDE SHOWN INSPECTION AREA S-25R S-25L S-20L S-14L S-10L

BL 0
STA 1016 

### (RIGHT SIDE ONLY) CARGO DOOR CUTOUT

540 STA 360 STA

S-26R S-14R

S-19R S-10R

S-26L



### B SEE B SEE
UP FWD

UP FWD 540

727 STA

STA

908 STAV21783

**(SHEET 1 OF 3) FIGURE 15: SKIN INSPECTIONS IN THE LOWER LOBE AREA**  Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 148 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT**

This Figure applies to Group 5, 8, 12, 17, 19-20: CRACKS TYPICAL

SKIN LOWER TYPICAL CRACK UPPER DOUBLER UPPER SKIN



### B C/L FRAME

1

INSPECTION

TYPICAL

AREA 1

C/L STRINGERV32403

**(SHEET 2 OF 3) FIGURE 15: SKIN INSPECTIONS IN THE LOWER LOBE AREA**  Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 149 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT**
The step numbers shown below agree with the numbers shown in the circle symbols in the figure. **STEP TASK NAME IDENTIFICATION QTY MORE DATA** 1 Inspect Fuselage Skin - - (a) (a) Do a detailed or general visual inspection for chem-mill cracks. If general visual inspections are accomplished in lieu of detailed inspections, then repeat inspection intervals are reduced as given in Paragraph 1.E., Compliance.

**(SHEET 3 OF 3) FIGURE 16: THIS FIGURE WAS DELETED AT REVISION 2**  Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 150 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT FIGURE 16: THIS FIGURE WAS DELETED AT REVISION 2** 

THIS FIGURE IS DELETED. .1553909

**(SHEET 1 OF 1) FIGURE 17: TIME-LIMITED SKIN REPAIR AT A LAP JOINT**  Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 151 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT FIGURE 17: TIME-LIMITED SKIN REPAIR AT A LAP JOINT** TYPICAL CRACK3FOR PART FABRICATIONASEEAND INSTALLATION1INSPECTION, FASTENER REMOVALAND SKIN TRIMTYPICAL CRACK LOCATIONINSPECTION AREA12X R O.501.0 1.0S-4S-10S-14542V22961

**(SHEET 1 OF 6) FIGURE 17: TIME-LIMITED SKIN REPAIR AT A LAP JOINT**  Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 152 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT**

The step numbers shown below agree with the numbers shown in the circle symbols in the figure.101179AND INSTALLATIONPART FABRICATION9869A130.901.20(TYPICAL)1.101.101214G4G44E4E4E4E4E4EE3E3E3F4E4E4E4F4F43F3F2G2G2G2G2G2G2G2G2G2GE3E3E3E3E3E3E3E3E3EEEEEEEE33333333EEEEEEE3333333GGGGG22G2G22G222GGGGG22G2G22G222GGGGG22G2G22G222GGGGG22G2G22G222G2G34E4E4E4E4E4EG3G34E4E4E4E4E4E3E3E3EG2G2G2G2G23G3G3G3G4GG2G2G2G2G2G2G2G3G3G3G3G3G3G3G3G3G3G3G3G3G3G3G3G3G3G3G3G3G3G34F4F4F3F3G3G3GG2G2G2G2G2(TYPICAL)FASTENEREXISTINGV22962

**(SHEET 2 OF 6) FIGURE 17: TIME-LIMITED SKIN REPAIR AT A LAP JOINT**  Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 153 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT NOTE:**  1. This repair cannot be used if the fasteners that exist are larger than 3/16 inch diameter. 2. This repair cannot be used in areas where hi-locks, lockbolts, or bolts were installed in production. If these fasteners are installed in the area of a crack, ask Boeing for repair data. 3. Report all cracks found at locations that do not require NDT inspections as given in this service bulletin or service bulletins 737-53-1065, 737-53-1168 or 737-53-1187 to Boeing. Include crack length, body station and stringer location, airplane identifier, and total accumulated flight-cycles. Provide photos when possible. 4. Install fasteners using the fastener pattern that exists as a guide in the fore and aft direction. Use this figure to determine fastener pitch in the circumferential direction. Make the distance between fasteners 0.90 - 1.20 inch. Maintain a minimum edge margin of two times the fastener diameter for new fastener locations and 1.7 times the fastener diameter for fastener locations that exist. 5. In the typical repair shown in this figure, the left side tear strap location shows a typical shear tie fastener pattern. The right side tear strap location shows a typical non-shear tied fastener pattern. The detail may be different, depending on the specific repair location. Use this figure as a guide, maintaining the same number and pattern of fasteners around the cutout, and common to the tear straps or shear ties. INSPECTION

FASTENER REMOVAL AND SKIN TRIM **STEP TASK NAME IDENTIFICATION QTY MORE DATA** 1 Inspect Fuselage Skin - - (a) 2 Inspect Lap Joint - - (b)

**(SHEET 3 OF 6) FIGURE 17: TIME-LIMITED SKIN REPAIR AT A LAP JOINT**  Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 154 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT NOTE:**  1. Trim skin as shown, regardless of crack length. 2. Maintain a minimum edge margin of 2 times the fastener diameter at all fastener locations. 3. Locate the trim lines so that the upper edge of the lower skin is not damaged. 4. Maintain a 63 micro-inch or better surface finish on all trimmed structure.

PART FABRICATION **NOTE:** 1. Size the repair parts to maintain a minimum edge margin of two times the fastener diameter at new fastener locations, and of 1.7 times the fastener diameter at existing fastener locations. 2. Maintain a minimum corner radius of 0.5 inch.

INSTALLATION **STEP TASK NAME IDENTIFICATION QTY MORE DATA** 3 Remove / Discard Fasteners - - In the area that will be common to the repair.
4 Trim Skin - - (c) Remove Trimmed Skin - 1 -

5 Apply Chemical Film Treatment Alodine or Iridite - (d) Primer BMS 10-79 TYPE II - 1 coat (d)

**STEP TASK NAME IDENTIFICATION QTY MORE DATA**
6 Measure Upper Skin Thickness - 1 - Make Doubler “A” 2024-T3 clad sheet 1 See table 1 (e) 7 Make Filler “B” 2024-T3 clad sheet 1 0.040 inch thick (e) (f) 8 Make Filler “C” 2024-T3 clad sheet 1 0.032 inch thick (e)
9 Apply Chemical Film Treatment Alodine or Iridite - - Primer BMS 10-79 TYPE II - 1 coat.

**(SHEET 4 OF 6) FIGURE 17: TIME-LIMITED SKIN REPAIR AT A LAP JOINT**  Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 155 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT NOTE:**  1. Shim all gaps from 0.01 - 0.04 inch prior to fastener installation. Contact Boeing for instructions for gaps greater than 0.04 inch. 2. Clean the faying surfaces of the fuselage skin and modification parts prior to the application of sealant. Refer to SOPM 20-50-19 as an accepted procedure.

Table 1 - Doubler Thickness Table **STEP TASK NAME IDENTIFICATION QTY MORE DATA**

10 Install Filler C 1 With BMS 5-95 faying surface sealant. 11 Install Filler B 1 With BMS 5-95 faying surface sealant. 12 Install Doubler A 1 With BMS 5-95 faying surface sealant.
13 Apply Fillet Seal - - Use BMS 5-95 sealant around the edges of the repair parts. 14 Apply Finish - - To the repaired area to match adjacent structure. (a) Do an external detailed inspection of the skin in the area of chem-milled step for cracks. Also do an external detailed inspection of the skin for cracks at the end holes common to the tear strap tabs. (b) Do an external detailed inspection of the skin and lap joint in the area of the repair for corrosion or disbonded doublers. Look for bulging, white powder, or a thin black line. If corrosion or disbond is found, contact Boeing. If no corrosion or disbond is found, continue with the repair. (c) The trim-out must be as shown to eliminate undetected cracks. The trim-out must be a minimum of 0.5 inch beyond the visible ends of the crack. If this is not possible, then accomplish HFEC inspections as given in 737 NDT, Part 6, 51-00-00 Figure 4 or 23. Do the HFEC inspection on the part surface around the trim out and on the cut end of the trim out, center the HFEC probe on the edge of the part that had the crack. If no cracks are found, trim an additional 0.04 inch around the cutout as an insurance cut. (d) To all cut edges of the skin. (e) Pre-form to match the contour of the fuselage. (f) This thickness is a target value. Use a thickness for this filler that makes the thickness of filler B plus the thickness of filler C the same thickness as the lap joint step (the thickness of the upper skin plus the bonded doubler), plus or minus 0.01 inch.

**Upper Skin Thickness**  **(inches) Doubler “A”**  **Thickness (inches)**  0.036 0.040 0.040 0.050 0.045 0.050 0.050 or greater Contact Boeing

**(SHEET 5 OF 6) FIGURE 17: TIME-LIMITED SKIN REPAIR AT A LAP JOINT**  Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 156 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT**

The codes shown below agree with the letter shown in the upper left corner of the fastener symbols in the figure. A number in the lower right corner gives the grip length of the fastener.
**CODE NAME IDENTIFICATION HOLE DIA MORE DATA** E Blind Rivet BACR15FR5E()R 0.176 - 0.180 (a)(b)(g) Blind Rivet BACR15FR6E()R 0.205 - 0.209 (a)(c)(d)(g) F Blind Rivet BACR15FR6E()R 0.205 - 0.209 (a)(e)(g) G Blind Rivet BACR15FR5E()R 0.176 - 0.180 (f)(g) (a) Install with a repair washer as given in 737-100/200 SRM 51-30-08, 737-300 SRM 51-40-08, 737-400 SRM 51-40-08, 737-500 SRM 51-40-08. (b) If the original fastener was 5/32 inch diameter. (c) Optional if it is necessary to make the hole larger to remove damage. (d) If the original fastener was 3/16 inch diameter. (e) Maintain a minimum edge margin at the shear tie of 1.5 times the fastener diameter. If this edge margin cannot be maintained, contact Boeing. (f) Use caution when locating these fasteners common to the tearstraps. Maintain a minimum edge margin of 1.7 times the fastener diameter from the edge of the tearstrap. (g) NAS1738E()-() optional to BACR15FR()E()R. 

### EXAMPLE OF FASTENER SYMBOL FASTENER LENGTH/GRIP FASTENER

D 6F
7 LETTER CODE DIAMETER (OPTIONAL) HEAD LOCATION N = NEAR SIDE F = FAR SIDE (OPTIONAL)

(OPTIONAL)V77720

**(SHEET 6 OF 6) FIGURE 18: INSPECTION OF THE TIME-LIMITED SKIN REPAIR AT A LAP JOINT**  Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 157 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT FIGURE 18: INSPECTION OF THE TIME-LIMITED SKIN REPAIR AT A LAP JOINT** S-14S-10S-4321SEEA1TIME - LIMITED REPAIRTYPICALEXTERNALINSPECTION AREAINSPECTION AREAINTERNALV27531

**(SHEET 1 OF 3) FIGURE 18: INSPECTION OF THE TIME-LIMITED SKIN REPAIR AT A LAP JOINT**  Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 158 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT**

The step numbers shown below agree with the numbers shown in the circle symbols in the figure. EXTERNAL INSPECTION **STEP TASK NAME IDENTIFICATION QTY MORE DATA** 1 Inspect Fuselage Skin - - (a)(b) (a) At the chem-milled step in each adjacent bay for cracks. If a crack is found, contact Boeing. If no cracks are found, continue with the inspections. (b) Do an External Subsurface Eddy Current in each adjacent bay for cracks as given in 737 NDT, Part 6, 53-30-09 or 737 NDT, Part 6, 53-30-18 or 737 NDT, Part 6, 53-30-19 or 737 NDT, Part 6, 53-30-25. COVERS THE LOWER SKIN TEAR STRAP OR DOUBLER TYPICAL WHERE THE THE LOWER SKIN TYPICAL WHERE IS NOT COVERED TEAR STRAP

FWD 4

4 3

2



### A ONE LAP JOINT CONFIGURATION SHOWN, OTHER CONFIGURATIONS SIMILARV27657

**(SHEET 2 OF 3) FIGURE 18: INSPECTION OF THE TIME-LIMITED SKIN REPAIR AT A LAP JOINT**  Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 159 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT** ONE-TIME INTERNAL INSPECTION **STEP TASK NAME IDENTIFICATION QTY MORE DATA** 2 Inspect Fuselage Skin Under Tear Strap - - (a)(b)(e) 3 Inspect Fuselage Skin - - (a)(c)(e) 4 Inspect Lap Joint - - (a)(d)(e) (a) Remove equipment as necessary from the passenger compartment to do an internal inspection of the skin at the lower row of fasteners in the lap joint. This inspection is only required one-time. (b) Do a Low Frequency Eddy Current inspection at the lower row of lap joint fasteners for cracks as given in 737 NDT, Part 6, 53-30-12. (c) Do a Medium Frequency Eddy Current inspection at the lower row of lap joint fasteners between tear straps as given in 737 NDT, Part 6, 53-30-16. (d) Do a general visual inspection for corrosion. Look for bulging, white powder, or a thin black line. (e) This inspection is not required at stringers S-10L and S-10R in the areas between STA 540 and STA 727.

**(SHEET 3 OF 3) FIGURE 19: THIS FIGURE WAS DELETED AT REVISION 2**  Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 160 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT FIGURE 19: THIS FIGURE WAS DELETED AT REVISION 2** 

THIS FIGURE IS DELETED. .1553909

**(SHEET 1 OF 1) FIGURE 20: THIS FIGURE**  **WAS DELETED AT REVISION 2** Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 161 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT FIGURE 20: THIS FIGURE WAS DELETED AT REVISION 2** 

THIS FIGURE IS DELETED. .1553909

**(SHEET 1 OF 1) FIGURE 21: SECTION 41 - EXTERNAL INSPECTION BETWEEN STA 259.5 AND STA 360 - S-19R TO**  **24R AND S-4L TO S-4R** Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 162 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT FIGURE 21: SECTION 41 - EXTERNAL INSPECTION BETWEEN STA 259.5 AND STA 360 - S-19R TO 24R**  **AND S-4L TO S-4R**

This Figure applies to Group 6-12, 15-18, 20: INSPECTION AREA STA 360 STA 259.5

BL 0 S-24R S-19R
S-14R

S-4R
S-4L

S-14L

S-24L BL 0 STA 259.5 STA 360

LAV

FWD GALLEY DOOR
FWD ENTRY DOOR 1

2 SEE A



### A1484869

**(SHEET 1 OF 2) FIGURE 21: SECTION 41 - EXTERNAL INSPECTION BETWEEN STA 259.5 AND STA 360 - S-19R TO**  **24R AND S-4L TO S-4R** Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 163 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT** The step numbers shown below agree with the numbers shown in the circle symbols in the figure. **STEP TASK NAME IDENTIFICATION QTY MORE DATA** 1 Inspect Skin Panel - - (a)(b) 2 Inspect Skin Panel - - (a)(b) (a) Do a detailed or general visual inspection for chem-mill cracks. If general visual inspections are accomplished in lieu of detailed inspections, then repeat inspection intervals are reduced as given in Paragraph 1.E., Compliance. (b) Skin panel areas which do not have shading are solid skin panels and do not require inspection.

**(SHEET 2 OF 2) FIGURE 22: SECTION 41 - EXTERNAL INSPECTION BETWEEN STA 259.5 AND STA 360 - S-24R TO S**  **24 L** Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 164 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT FIGURE 22: SECTION 41 - EXTERNAL INSPECTION**  **BETWEEN STA 259.5 AND STA 360 - S-24R TO S 24 L** 

This Figure applies to Group 4-5, 13-14, 19, 21: INSPECTION AREA STA 360 STA 259.5

BL 0 S-24R S-19R
S-14R

S-4R
S-4L

S-14L

S-24L BL 0 STA 259.5 STA 360

LAV

FWD GALLEY DOOR
FWD ENTRY DOOR 1 SEE A



### A1484872

**(SHEET 1 OF 2) FIGURE 22: SECTION 41 - EXTERNAL INSPECTION BETWEEN STA 259.5 AND STA 360 - S-24R TO S**  **24 L** Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 165 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT** The step numbers shown below agree with the numbers shown in the circle symbols in the figure. **STEP TASK NAME IDENTIFICATION QTY MORE DATA** 1 Inspect Skin Panel - - (a)(b) (a) Do a detailed or general visual inspection for chem-mill cracks. If general visual inspections are accomplished in lieu of detailed inspections, then repeat inspection intervals are reduced as given in Paragraph 1.E., Compliance. (b) Skin panel areas which do not have shading are solid skin panels and do not require inspection.

**(SHEET 2 OF 2) FIGURE 23: TEAR STRAP ATTACHMENT TO SKIN INSPECTION**  Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 166 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT FIGURE 23: TEAR STRAP ATTACHMENT TO SKIN INSPECTION** 

This Figure applies to Group 1-5, 9-21: S-14L S-10L S-4L S-4R

UPPER DOUBLER

SKIN LOWER UPPER SKIN TYPICAL CRACK

STA 259.5 STA 1016

10.00 C/L FRAME

TYPICAL
AREA INSPECTION C/L STRINGER1484891

**(SHEET 1 OF 2) FIGURE 23: TEAR STRAP ATTACHMENT TO SKIN INSPECTION**  Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 167 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT** The step numbers shown below agree with the numbers shown in the circle symbols in the figure. **STEP TASK NAME IDENTIFICATION QTY MORE DATA** 1 Inspect Skin at the Tear Strap Tab End Holes - - (a)(b) (a) Do a High Frequency Eddy current (HFEC) inspection of the fuselage skin (external) at each tear strap attachment at locations identified in Figures 3-7, 45 and 46 for chem-mill inspections at lap joints as given in 737 NDT, Part 6, 53-30-05 or 737 NDT, Part 6, 51-00-00 Figure 15. (b) If external eddy current inspections can not be accomplished because of interference with external doublers, then refer to Paragraph 1.E., Compliance for guidance.

**(SHEET 2 OF 2) FIGURE 24: SKIN CHEM-MILL LINE CRACK AT STRINGER 12 - REPAIR**  Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 168 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT FIGURE 24: SKIN CHEM-MILL LINE CRACK AT STRINGER 12 - REPAIR** 

ALLOWABLE TRIM AREA TYPICAL

CRACK

STA 520 TYPICAL LAP DOUBLER STA 540 STA 360

500D = 737-300 482B = 737-500 S-12 TYPICAL LAP DOUBLER

UP
FWD



### A SEE A B SEE

SEE C 1 3 4

RIGHT SIDE SHOWN LEFT SIDE OPPOSITE 21484918

**(SHEET 1 OF 7) FIGURE 24: SKIN CHEM-MILL LINE CRACK AT STRINGER 12 - REPAIR**  Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 169 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT**

SKIN TRIM B 5

UP
FWD 6 7 8 9 6 7 8 9

2X R O.50 TYPICAL CRACK1485239

**(SHEET 2 OF 7) FIGURE 24: SKIN CHEM-MILL LINE CRACK AT STRINGER 12 - REPAIR**  Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 170 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT**

This Figure applies to Group 3, 5, 9-10, 12, 14-15, 17-21: E

E

E

E

E

E

E

E E

E

E

E

E

E

E

E S-12

STA 520

D
D
D
D D D D D

D
D
D
D D D D

D D TYPICAL LAP DOUBLER

TYPICAL LAP DOUBLER D D D D D D D D D D D D D D D D D D D A A A A A A A B A A A A A A A

A A A A A A A B A A A A A A A DOUBLER
TRIPLER

DOUBLER 500D = 737-300 482B = 737-500 UP
FWD C C C
C C C
C C C
C
C C C
C C C
C C C C C
C C
C

C
C
C
C C

C
C
C
C



### C A A A

A A A A A

A A 10 11

18 19 20 22 23

21 16 17 15 25 26 21

24 12

14 13

B
B
B

B B B B C C C C C C C C C C C C C C

C C C C C C C C C C C C C C C C C C C C C C C C C C C C C C C C C C C

C C C C C C C C C C C C C C C C C C C C C C C C C C C C C C C C C C C C C C C C C C C C C C C C C C C C C C C C C C C C C C C B
B

B B1485261

**(SHEET 3 OF 7) FIGURE 24: SKIN CHEM-MILL LINE CRACK AT STRINGER 12 - REPAIR**  Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 171 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT** The step numbers shown below agree with the numbers shown in the circle symbols in the figure.

**STEP TASK NAME IDENTIFICATION QTY MORE**  **DATA** 1 Inspect Fuselage Skin - - (a) 2 Inspect Fuselage Skin - - (b) 3 Remove Fasteners - - (c) 4 Inspect Fastener Holes - - (d) 5 Inspect Fuselage Skin - - (e) 6 Cut Fuselage Skin - - (f) 7 Inspect Fuselage Skin - - (g) 8 Cut Fuselage Skin - - (h) 9 Apply Chemical Conversion Coating Type 2, Class A - (i) 10 Make Doubler .032 inch 2024-T3 - (j) 11 Make Tripler .050 inch 2024-T3 - (k)(l) 12 Make Tearstrap Splice Strap .040 inch 2024-T3 - (m) 13 Make Tapered Filler .040 inch 2024-T3 - (m) 14 Make Tapered Filler .040 inch 2024-T3 - (m) 15 Drill Holes - - (n) 16 Mark Holes - - (o) 17 Drill Holes - - (p) 18 Deburr Repair - - (q) 19 Apply Chemical Conversion Coating Type 2, Class A - (r) 20 Apply Primer BMS 10-79 type II or type III primer - (s) 21 Install Repair Washers - - (t) 22 Clean Repair - - (u)

23 Apply Sealant BMS 5-95 - (v) Locate Repair - - Install Fasteners - - 24 Apply Fillet Seal BMS 5-95 (w) 25 Apply Corrosion Inhibiting Compound BMS 3-23 type 2 - (x) 26 Apply Finish - - (y) (a) Do an External Subsurface Eddy Current inspection of the chem-milled step in each adjacent bay for chem-mill cracks as given in 737 NDT, Part 6, 53-30-09 or 737 NDT, Part 6, 53-30-18 or 737 NDT, Part 6, 53-30-19 or 737 NDT, Part 6, 53-30-25. (b) This repair can be used for up to 4 cracks provided they are contained between tearstraps in the shaded areas. (c) From the area that will be common to the repair.

**(SHEET 4 OF 7) FIGURE 24: SKIN CHEM-MILL LINE CRACK AT STRINGER 12 - REPAIR**  Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 172 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT**

(d) Do an High Frequency Eddy Current (HFEC) inspections of all fastener holes common to the repair doubler, including the window frame as given in 737 NDT, Part 6, 51-00-00 figure 16, using .030 inch notch sensitivity. (e) Do an internal detailed inspection of the skin, bonded doubler and frames in the area of the repair for cracks, corrosion or disbonded doublers. Look for bulging, white powder, or a thin black line. If cracks, corrosion or disbond is found, contact Boeing. If no cracks, corrosion or disbond is found, continue with the repair. (f) Carefully cut and remove the damaged part of the skin. Make sure that a minimum of .50 inch radius is maintained. If necessary, use a thin steel sheet to protect adjacent structure. The cutout must be contained between tearstraps. Do not cut into the tearstrap. (g) HFEC inspect along the edge of the cutouts as given in 737 NDT, Part 6, 51-00-00 figure 4 or 23. Make sure there are no cracks, and disbond between the strap and skin. (h) If there is no further damage, make the cutout larger by .040 inch as insurance cut. All cutout edges must have a finish of 63 Ra or better. The cutout must be contained between tearstraps. Do not cut into the tearstrap. (i) Apply one coat of chemical conversion coating to all cut surfaces of the skin panel. Refer to 737-300 SRM 51-20-01 or 737-500 SRM 51-20-01 as an accepted procedure. (j) Make doubler from .032 inch 2024-T3 Clad Aluminum. Make sure a 2D edge margin and a 0.50 inch minimum outside corner radius is maintained. Pre-form to match the fuselage contour. (k) Make tripler from .050 inch 2024-T3 Clad Aluminum. Make sure a 2D edge margin and a 0.50 inch minimum outside corner radius is maintained. Pre-form to match the fuselage contour. (l) Chamfer the edges of the tripler. Refer to 737-300 SRM 51-10-01 or 737-500 SRM 51-10-01 as an accepted procedure. (m) Make tearstrap splice strap and tapered fillers from 0.04 inch 2024-T3 clad aluminum. Make sure a 2D edge margin and a 0.50 inch minimum outside corner radius is maintained. Taper the fillers from 0.04 to 0.01 at a minimum 50:1 taper ratio. (n) Drill existing holes into doubler and tripler. (o) Mark out new hole positions. Use the guide lines of the figure. Make sure a 2D edge margin and a minimum 5D fastener spacing is maintained. (p) Drill new hole positions into doubler, tripler, splice strap and skin panel. (q) Remove all nicks, scratches, gouges, burrs, and sharp edges from the skin panel, doubler and tripler. Make sure machined surfaces to be 63 Ra or better. (r) Apply one coat of chemical conversion coating to all bare surfaces of the skin panel, doubler and tripler. Refer to 737-300 SRM 51-20-01 or 737-500 SRM 51-20-01 as an accepted procedure. (s) Apply two coats of BMS 10-79 type II or type III primer to all bare surfaces of the skin panel, doubler and tripler. Refer to 737-300 SRM 51-20-01 or 737-500 SRM 51-20-01as an accepted procedure. (t) Install repair washers in the countersink holes in the skin panels between the doubler and the skin panel. Install all repair washers with BMS 5-95 Class B-1/2 or B-2 sealant. Refer to 737-300 SRM 51-40-08 or 737-500 SRM 51-40-08 and SOPM 20-50-19 as an accepted procedures. (u) Clean the mating surfaces of the skin panel, doubler and tripler to be sealed. Refer to 737-300 SRM 51-20-05 or 737-500 SRM 51-20-05 as an accepted procedure. (v) Apply BMS 5-95 Class B-1/2 or B-2 sealant to the mating surfaces of the skin panel, doubler and tripler. Refer to SOPM 20-50-19 as an accepted procedure. Refer to fastener code table for fastener installation.

**STEP TASK NAME IDENTIFICATION QTY MORE**  **DATA**

**(SHEET 5 OF 7) FIGURE 24: SKIN CHEM-MILL LINE CRACK AT STRINGER 12 - REPAIR**  Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 173 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT**

The codes shown below agree with the letter shown in the upper left corner of the fastener symbols in the figure. A number in the lower right corner gives the grip length of the fastener. The QTY numbers shown below are the number of fasteners necessary for this figure. If the grip length shown is not available at Boeing, fasteners supplied in kits may be one grip length longer than indicated. Also, if any of the fastener part numbers are not available or have been superseded, substitute fasteners may be supplied in Boeing kits, Boeing Document D-590 and Boeing drawing 65-88700 are used to determine the part numbers used as substitutes.

(w) Apply fillet sealant along the edges of the doubler and tripler. Refer to SOPM 20-50-19 as an accepted procedure. (x) Apply a layer of BMS 3-23 type 2 corrosion inhibiting compound onto the internal surface of the entire repair area. Refer to 737-300 SRM 51-20-01 or 737-500 SRM 51-20-01 as an accepted procedure. (y) Restore the original finish of the external surface of the repair area. Refer to 737-300/400/500 AMM 51-21-00 as an accepted procedure.

**CODE NAME IDENTIFICATION QTY HOLE DIA MORE DATA** A Rivet BACR15BB6AD( ) 38 0.190 - 0.196 (a)(b) B Rivet BACR15BB6D( ) 14 0.190 - 0.196 (a)(b) C Rivet BACR15CE5D( ) 123 0.159 - 0.165 (a)(b) D Rivet BACR15BB6D( ) 37 0.190 - 0.196 (a)(b) E Rivet BACR15BB10D( ) 16 0.316 - 0.322 (a)(c)(d)(e) Bolt BACB30FM10A( ) 16 0.309 - 0.313 (a) Install all new rivets dry. (b) The minimum diameter of the driven head of the rivet is 1.4 times the fastener diameter. **STEP TASK NAME IDENTIFICATION QTY MORE**  **DATA**



### EXAMPLE OF FASTENER SYMBOL FASTENER LENGTH/GRIP FASTENER

D 6F
7 LETTER CODE DIAMETER (OPTIONAL) HEAD LOCATION N = NEAR SIDE F = FAR SIDE (OPTIONAL)

(OPTIONAL)V77720

**(SHEET 6 OF 7) FIGURE 24: SKIN CHEM-MILL LINE CRACK AT STRINGER 12 - REPAIR**  Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 174 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT**

(c) If existing fastener was a rivet, install a new rivet. If existing fastener was a bolt, install a new bolt. (d) Install all bolts wet with BMS 5-95 Class B-1/2 or B-2. Refer to SOPM 20-50-19 as an accepted procedure. (e) Oversize fastener hole to remove the countersink. Make sure a minimum edge margin of 1.7 times the fastener diameter is maintained. If this edge margin cannot be maintained, contact Boeing.

**CODE NAME IDENTIFICATION QTY HOLE DIA MORE DATA**

**(SHEET 7 OF 7) FIGURE 25: INSPECTION FOR VERTICAL CRACKS AT CHEM-MILL LINES OF FUSELAGE SKIN**  Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 175 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT FIGURE 25: INSPECTION FOR VERTICAL CRACKS AT CHEM-MILL LINES OF FUSELAGE SKIN** 

S-10R

S-19R S-17R STA 360 STA 540 STA 727 STA 908 STA 460

STA 312 STA 500C

STA 727G

1 B SEE SEE C

SEE A SEE C SEE C SEE C

C SEE SEE C



### 737-400 AIRPLANES 2 1 9

1 8

1 7

1 6 1 5 1 4 1 31488582

**(SHEET 1 OF 4) FIGURE 25: INSPECTION FOR VERTICAL CRACKS AT CHEM-MILL LINES OF FUSELAGE SKIN**  Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 176 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT**

INSPECTION AREA TYPICAL CRACK INSPECTION AREA TYPICAL CRACK

UP
FWD S-17R UP
FWD S-19R

S-20R LOWER SKIN PANEL LAP JOINT UPPER SKIN PANEL



### B STA 460 STA 469.90

EDGE OF SKIN 

### A STA 312

2 1

4 11488645

**(SHEET 2 OF 4) FIGURE 25: INSPECTION FOR VERTICAL CRACKS AT CHEM-MILL LINES OF FUSELAGE SKIN**  Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 177 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT**

This Figure applies to Group 4, 11, 16: 

### INSPECTION AREA TYPICAL CRACK TYPICAL CRACK

UP
FWD STRINGER

STRINGER

STRINGER

STRINGER

STRINGER



### C BUTT JOINT LAP JOINT UPPER AFT SKIN PANEL UPPER FORWARD SKIN PANEL



### TYPICAL CIRCUMFERENTIAL BUTT SPLICE 1 3 5 6 7 8 91494540

**(SHEET 3 OF 4) FIGURE 25: INSPECTION FOR VERTICAL CRACKS AT CHEM-MILL LINES OF FUSELAGE SKIN**  Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 178 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT** The step numbers shown below agree with the numbers shown in the circle symbols in the figure. **STEP TASK NAME IDENTIFICATION QTY MORE DATA** 1 Inspect Skin Panel - - (a) 2 Inspect Skin Panel - - (b) 3 Inspect Skin Panel - - (c) 4 Inspect Skin Panel - - (d) 5 Inspect Skin Panel - - (e) 6 Inspect Skin Panel - - (f) 7 Inspect Skin Panel - - (g) 8 Inspect Skin Panel - - (h) 9 Inspect Skin Panel - - (i) (a) Do an external detailed inspection of the fuselage skin for chem-mill cracks. (b) Do a Low Frequency Eddy Current (LFEC) or Magneto Optical Imaging (MOI) or C-Scan inspection at STA 312 below S-19R for vertical subsurface skin cracks as given in 737 NDT, Part 6, 53-30-09 or 737 NDT, Part 6, 53-30-18 or 737 NDT, Part 6, 53-30-19 or 737 NDT, Part 6, 53-30-25. (c) Do a LFEC or MOI or C-Scan inspection at the circumferential butt splice STA 360 between S-10L and S-10R for vertical subsurface skin cracks as given in 737 NDT, Part 6, 53-30-09 or 737 NDT, Part 6, 53-30-18 or 737 NDT, Part 6, 53-30-19 or 737 NDT, Part 6, 53-30-25. (d) Do a LFEC or MOI or C-Scan inspection at STA 460 below S-17R for vertical subsurface skin cracks as given in 737 NDT, Part 6, 53-30-09 or 737 NDT, Part 6, 53-30-18 or 737 NDT, Part 6, 53-30-19 or 737 NDT, Part 6, 53-30-25. (e) Do a LFEC or MOI or C-Scan inspection at the circumferential butt splice STA 500C between S-10L and S-10R for vertical subsurface skin cracks as given in 737 NDT, Part 6, 53-30-09 or 737 NDT, Part 6, 53-30-18 or 737 NDT, Part 6, 53-30-19 or 737 NDT, Part 6, 53-30-25. (f) Do a LFEC or MOI or C-Scan inspection at the circumferential butt splice STA 540 between S-10L and S-10R for vertical subsurface skin cracks as given in 737 NDT, Part 6, 53-30-09 or 737 NDT, Part 6, 53-30-18 or 737 NDT, Part 6, 53-30-19 or 737 NDT, Part 6, 53-30-25. (g) Do a LFEC or MOI or C-Scan inspection at the circumferential butt splice STA 727 between S-10L and S-10R for vertical subsurface skin cracks as given in 737 NDT, Part 6, 53-30-09 or 737 NDT, Part 6, 53-30-18 or 737 NDT, Part 6, 53-30-19 or 737 NDT, Part 6, 53-30-25. (h) Do a LFEC or MOI or C-Scan inspection at the circumferential butt splice STA 727G between S-10L and S-10R for vertical subsurface skin cracks as given in 737 NDT, Part 6, 53-30-09 or 737 NDT, Part 6, 53-30-18 or 737 NDT, Part 6, 53-30-19 or 737 NDT, Part 6, 53-30-25. (i) Do a LFEC or MOI or C-Scan inspection at the circumferential butt splice STA 908 between S-10L and S-10R for vertical subsurface skin cracks as given in 737 NDT, Part 6, 53-30-09 or 737 NDT, Part 6, 53-30-18 or 737 NDT, Part 6, 53-30-19 or 737 NDT, Part 6, 53-30-25.

**(SHEET 4 OF 4) FIGURE 26: SKIN INSPECTION - LEFT AND RIGHT HAND SIDE BETWEEN STA 360 AND STA 540,**  **STRINGER 14 - STRINGER 26** Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 179 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT FIGURE 26: SKIN INSPECTION - LEFT AND RIGHT HAND SIDE BETWEEN STA 360 AND STA 540,**  **STRINGER 14 - STRINGER 26**



### S-16L STA 360 S-18L S-20L S-22L S-26L S-14L STA 500A STA 540

STA 440

S-16R STA 360 S-18R S-20R S-22R S-26R S-14R STA 500A STA 540

STA 440 FWD

FWD C SEE SEE B



### 737-300 LEFT SIDE A SEE

F

SEE

SEE E
D SEE



### 737-300 RIGHT SIDE1491147

**(SHEET 1 OF 9) FIGURE 26: SKIN INSPECTION - LEFT AND RIGHT HAND SIDE BETWEEN STA 360 AND STA 540,**  **STRINGER 14 - STRINGER 26** Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 180 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT**

EDDY CURRENT INSPECTION AREA S-14L

S-15L

S-16L

S-17L

S-18L

S-19L

S-20L

S-21L

S-22L

S-23L

S-24L

S-25L

S-26L STA 370 STA 380 STA 390 STA 400 STA 410 STA 420 STA 360 STA 430 STA 440



### A LAP JOINT UPPER SKIN

LOWER SKIN

FWD UP 1 G SEE1494612

**(SHEET 2 OF 9) FIGURE 26: SKIN INSPECTION - LEFT AND RIGHT HAND SIDE BETWEEN STA 360 AND STA 540,**  **STRINGER 14 - STRINGER 26** Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 181 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT**

EDDY CURRENT INSPECTION AREA S-14L

S-15L

S-16L

S-17L

S-18L

S-19L

S-20L

S-21L

S-22L

S-23L

S-24L

S-25L

S-26L STA 450 STA 460 STA 470 STA 480 STA 490 STA 500 STA 440 STA 500A



### B LAP JOINT UPPER SKIN

LOWER SKIN

FWD UP 1 G SEE1491160

**(SHEET 3 OF 9) FIGURE 26: SKIN INSPECTION - LEFT AND RIGHT HAND SIDE BETWEEN STA 360 AND STA 540,**  **STRINGER 14 - STRINGER 26** Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 182 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT**

EDDY CURRENT INSPECTION AREA S-14L

S-15L

S-16L

S-17L

S-18L

S-19L

S-20L

S-21L

S-22L

S-23L

S-24L

S-25L

S-26L STA 500B STA 500C STA 500D STA 510 STA 530 STA 520 STA 540



### C LAP JOINT UPPER SKIN

LOWER SKIN

FWD UP 1 G SEE1494639

**(SHEET 4 OF 9) FIGURE 26: SKIN INSPECTION - LEFT AND RIGHT HAND SIDE BETWEEN STA 360 AND STA 540,**  **STRINGER 14 - STRINGER 26** Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 183 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT**

EDDY CURRENT INSPECTION AREA STA 430 STA 420 STA 410 STA 400 STA 390 STA 380 STA 440 STA 370 STA 360 S-14R

S-15R

S-16R

S-17R

S-18R

S-19R

S-20R

S-21R

S-22R

S-23R

S-24R

S-25R

S-26R UP
FWD 

### D LAP JOINT UPPER SKIN

LOWER SKIN 1 G SEE1491162

**(SHEET 5 OF 9) FIGURE 26: SKIN INSPECTION - LEFT AND RIGHT HAND SIDE BETWEEN STA 360 AND STA 540,**  **STRINGER 14 - STRINGER 26** Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 184 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT**

EDDY CURRENT INSPECTION AREA STA 500A STA 500 STA 490 STA 480 STA 470 STA 460 STA 450 STA 440 S-14R

S-15R

S-16R

S-17R

S-18R

S-19R

S-20R

S-21R

S-22R

S-23R

S-24R

S-25R

S-26R UP
FWD 

### E LAP JOINT UPPER SKIN

LOWER SKIN 1 G SEE

CARGO DOOR CUTOUT1491421

**(SHEET 6 OF 9) FIGURE 26: SKIN INSPECTION - LEFT AND RIGHT HAND SIDE BETWEEN STA 360 AND STA 540,**  **STRINGER 14 - STRINGER 26** Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 185 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT**

EDDY CURRENT INSPECTION AREA STA 530 STA 510 STA 500D STA 500C STA 500B STA 520 STA 540 S-14R

S-15R

S-16R

S-17R

S-18R

S-19R

S-20R

S-21R

S-22R

S-23R

S-24R

S-25R

S-26R UP
FWD 

### F LAP JOINT UPPER SKIN

LOWER SKIN 1 G SEE1494725

**(SHEET 7 OF 9) FIGURE 26: SKIN INSPECTION - LEFT AND RIGHT HAND SIDE BETWEEN STA 360 AND STA 540,**  **STRINGER 14 - STRINGER 26** Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 186 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT**

This Figure applies to Group 3, 6, 9-10, 14-15, 18, 21: 

### FRAME FRAME
SKIN DOUBLER EDGE OF BONDED

STRINGER

STRINGER

TYPICAL BAY FRAME FRAME

STRINGER STRINGER

TYPICAL BAY NEXT TO WING-TO-BODY FAIRING TYPICAL CRACK

TYPICAL CRACK

TYPICAL CRACK TYPICAL CRACK 1



### G

G 11548926

**(SHEET 8 OF 9) FIGURE 26: SKIN INSPECTION - LEFT AND RIGHT HAND SIDE BETWEEN STA 360 AND STA 540,**  **STRINGER 14 - STRINGER 26** Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 187 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT** The step numbers shown below agree with the numbers shown in the circle symbols in the figure. **STEP TASK NAME IDENTIFICATION QTY MORE DATA** 1 Inspect Fuselage Skin - - (a) (a) Do an eddy current inspection for chem-mill cracks as given in 737 NDT, Part 6, 53-30-09 or 737 NDT, Part 6, 53-30-18 or 737 NDT, Part 6, 53-30-19 or 737 NDT, Part 6, 53-30-25.

**(SHEET 9 OF 9) FIGURE 27: SKIN INSPECTION - RIGHT HAND SIDE BETWEEN STA 360 AND STA 540, STRINGER 14**  **- STRINGER 26** Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 188 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT FIGURE 27: SKIN INSPECTION - RIGHT HAND SIDE BETWEEN STA 360 AND STA 540, STRINGER 14 -**  **STRINGER 26**



### S-16L S-18L

S-20L S-22L S-26L S-14L STA 440 STA 540

STA 360

STA 360 STA 440 STA 482A

S-16R S-18R S-20R S-22R S-26R S-14R STA 482A FWD

FWD C SEE SEE B



### 737-500 LEFT SIDE A SEE

SEE E D SEE



### 737-500 RIGHT SIDE1494796

**(SHEET 1 OF 8) FIGURE 27: SKIN INSPECTION - RIGHT HAND SIDE BETWEEN STA 360 AND STA 540, STRINGER 14**  **- STRINGER 26** Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 189 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT**

EDDY CURRENT INSPECTION AREA S-14L

S-15L

S-16L

S-17L

S-18L

S-19L

S-20L

S-21L

S-22L

S-23L

S-24L

S-25L

S-26L STA 370 STA 380 STA 390 STA 400 STA 410 STA 420 STA 360 STA 430 STA 440



### A LAP JOINT UPPER SKIN

LOWER SKIN

FWD UP

1 F SEE1494810

**(SHEET 2 OF 8) FIGURE 27: SKIN INSPECTION - RIGHT HAND SIDE BETWEEN STA 360 AND STA 540, STRINGER 14**  **- STRINGER 26** Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 190 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT**

EDDY CURRENT INSPECTION AREA S-14L

S-15L

S-16L

S-17L

S-18L

S-19L

S-20L

S-21L

S-22L

S-23L

S-24L

S-25L

S-26L STA 460 STA 482 STA 482A STA 440



### B LAP JOINT UPPER SKIN

LOWER SKIN

FWD UP 1 F SEE1494824

**(SHEET 3 OF 8) FIGURE 27: SKIN INSPECTION - RIGHT HAND SIDE BETWEEN STA 360 AND STA 540, STRINGER 14**  **- STRINGER 26** Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 191 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT**

EDDY CURRENT INSPECTION AREA S-14L

S-15L

S-16L

S-17L

S-18L

S-19L

S-20L

S-21L

S-22L

S-23L

S-24L

S-25L

S-26L STA 482B STA 520 STA 540 STA 482A



### C LAP JOINT UPPER SKIN

LOWER SKIN

FWD UP 1 F SEE1495099

**(SHEET 4 OF 8) FIGURE 27: SKIN INSPECTION - RIGHT HAND SIDE BETWEEN STA 360 AND STA 540, STRINGER 14**  **- STRINGER 26** Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 192 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT**

CARGO

DOOR CUTOUT

EDDY CURRENT INSPECTION AREA STA 430 STA 420 STA 410 STA 400 STA 390 STA 380 STA 440 STA 370 STA 360 S-14R

S-15R

S-16R

S-17R

S-18R

S-19R

S-20R

S-21R

S-22R

S-23R

S-24R

S-25R

S-26R UP
FWD 

### D LAP JOINT UPPER SKIN

LOWER SKIN 1 F SEE1495108

**(SHEET 5 OF 8) FIGURE 27: SKIN INSPECTION - RIGHT HAND SIDE BETWEEN STA 360 AND STA 540, STRINGER 14**  **- STRINGER 26** Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 193 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT**

EDDY CURRENT INSPECTION AREA STA 482A STA 482 STA 460 STA 440 S-14R

S-15R

S-16R

S-17R

S-18R

S-19R

S-20R

S-21R

S-22R

S-23R

S-24R

S-25R

S-26R UP
FWD



### E LAP JOINT UPPER SKIN

LOWER SKIN 1 F SEE

CARGO DOOR CUTOUT1495109

**(SHEET 6 OF 8) FIGURE 27: SKIN INSPECTION - RIGHT HAND SIDE BETWEEN STA 360 AND STA 540, STRINGER 14**  **- STRINGER 26** Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 194 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT**

This Figure applies to Group 5, 8, 12, 17, 19-20: 

### FRAME FRAME
SKIN DOUBLER EDGE OF BONDED

STRINGER

STRINGER

TYPICAL BAY FRAME FRAME

STRINGER STRINGER

TYPICAL BAY NEXT TO WING-TO-BODY FAIRING TYPICAL CRACK

TYPICAL CRACK

TYPICAL CRACK TYPICAL CRACK 1



### F

F 11548936

**(SHEET 7 OF 8) FIGURE 27: SKIN INSPECTION - RIGHT HAND SIDE BETWEEN STA 360 AND STA 540, STRINGER 14**  **- STRINGER 26** Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 195 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT** The step numbers shown below agree with the numbers shown in the circle symbols in the figure. **STEP TASK NAME IDENTIFICATION QTY MORE DATA** 1 Inspect Fuselage Skin - - (a) (a) Do an eddy current inspection for chem-mill cracks as given in 737 NDT, Part 6, 53-30-09 or 737 NDT, Part 6, 53-30-18 or 737 NDT, Part 6, 53-30-19 or 737 NDT, Part 6, 53-30-25.

**(SHEET 8 OF 8) FIGURE 28: SECTION 41 - SKIN INSPECTION**  **- STRINGER-18R AND STRINGER-19R BETWEEN STA 303 AND STA 320 AND STRINGER- 15R BETWEEN STA 344 AND STA 352**  Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 196 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT FIGURE 28: SECTION 41 - SKIN INSPECTION - ST**  **RINGER-18R AND STRINGER-19R BETWEEN STA 303 AND STA 320 AND STRINGER- 15R BETWEEN STA 344 AND STA 352** 



### EDDY CURRENT INSPECTION AREA STA 360 STA 259.5

STA 328 STA 344 STA 352 STA 303

STA 360 SERVICE DOOR S-14R
S-15R S-16R S-17R
S-18R

S-19R
S-20R S-21R STA 320

STA 294.5 STA 312 UP
FWD SEE A



### A 1

2

3 B SEE

B SEE B SEE1495114

**(SHEET 1 OF 2) FIGURE 28: SECTION 41 - SKIN INSPECTION**  **- STRINGER-18R AND STRINGER-19R BETWEEN STA 303 AND STA 320 AND STRINGER- 15R BETWEEN STA 344 AND STA 352**  Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 197 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT**

This Figure applies to Group 1-5, 13-14, 19, 21: The step numbers shown below agree with the numbers shown in the circle symbols in the figure. **STEP TASK NAME IDENTIFICATION QTY MORE DATA** 1 Inspect Skin Panel - - (a) 2 Inspect Skin Panel - - (b) 3 Inspect Skin Panel - - (c) (a) Do a LFEC or MOI or C-Scan inspection between STA 344 and STA 352 below S-14R for subsurface skin cracks as given in 737 NDT, Part 6, 53-30-09 or 737 NDT, Part 6, 53-30-18 or 737 NDT, Part 6, 53-30-19 or 737 NDT, Part 6, 53-30-25. (b) Do a LFEC or MOI or C-Scan inspection between STA 303 and STA 320 below S-18R for subsurface skin cracks as given in 737 NDT, Part 6, 53-30-09 or 737 NDT, Part 6, 53-30-18 or 737 NDT, Part 6, 53-30-19 or 737 NDT, Part 6, 53-30-25. (c) Do a LFEC or MOI or C-Scan inspection between STA 303 and STA 320 above S-19R for subsurface skin cracks as given in 737 NDT, Part 6, 53-30-09 or 737 NDT, Part 6, 53-30-18 or 737 NDT, Part 6, 53-30-19 or 737 NDT, Part 6, 53-30-25. 

### FRAME FRAME
SKIN DOUBLER EDGE OF BONDED

STRINGER

STRINGER

TYPICAL BAY TYPICAL CRACK

TYPICAL CRACK 1



### B 2 31548941

**(SHEET 2 OF 2) FIGURE 29: SKIN INSPECTIONS IN THE LOWER LOBE AREA**  Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 198 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT FIGURE 29: SKIN INSPECTIONS IN THE LOWER LOBE AREA** 

259.50

STA 360 STA 540 STA STA 727 STA 908 STA 1016

S-26R

S-19R S-25R S-24R
S-19R
S-14R

S-24L S-19L S-14L S-20R
S-14R

S-14L
S-20L S-25L BL 0

BL 0

737-300 AIRPLANE TYPICAL INSPECTION AREA SEE A

SEE A1495639

**(SHEET 1 OF 3) FIGURE 29: SKIN INSPECTIONS IN THE LOWER LOBE AREA**  Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 199 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT**

This Figure applies to Group 6, 9-10, 14-15, 18, 21: CRACKS TYPICAL

SKIN LOWER TYPICAL CRACK UPPER DOUBLER UPPER SKIN



### A C/L FRAME

1

INSPECTION

TYPICAL

AREA 1

C/L STRINGER1496492

**(SHEET 2 OF 3) FIGURE 29: SKIN INSPECTIONS IN THE LOWER LOBE AREA**  Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 200 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT** The step numbers shown below agree with the numbers shown in the circle symbols in the figure. **STEP TASK NAME IDENTIFICATION QTY MORE DATA** 1 Inspect Fuselage Skin - - (a) (a) Do a detailed or general visual inspection for chem-mill cracks. If general visual inspections are accomplished in lieu of detailed inspections, then repeat inspection intervals are reduced. Refer to Paragraph 1.E., Compliance for repeat inspection interval requirements.

**(SHEET 3 OF 3) FIGURE 30: TYPICAL INTERNAL INSPECTION**  Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 201 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT FIGURE 30: TYPICAL INTERNAL INSPECTION** 



### 480 STA

S-18

S-20

S-22 360 STA

RIGHT SIDE OPPOSITE LEFT SIDE SHOWN S-14

FWD B SEE A 2 11495668

**(SHEET 1 OF 3) FIGURE 30: TYPICAL INTERNAL INSPECTION**  Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 202 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT**

BONDED EDGE OF DOUBLER CRACKS SKIN 0.25

0.25 STRINGER

STRINGER FRAME FRAME 0.25 EDGE OF BONDED DOUBLER

ASSEMBLY SKIN PANEL FRAME FRAME FRAME

SKIN CRACK STRINGER

STRINGER

STRINGER

DOUBLER INSPECTION ZONE NEAR SKIN CRACK

CRACK AT WING-TO-BODY FAIRING 1 2

2 2 1



### A

B1495678

**(SHEET 2 OF 3) FIGURE 30: TYPICAL INTERNAL INSPECTION**  Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 203 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT** The step numbers shown below agree with the numbers shown in the circle symbols in the figure. When cracking is found in the skin, accomplish the internal inspections of the bonded doubler as follows: **STEP TASK NAME IDENTIFICATION QTY MORE DATA** 1 Inspect Bonded Doubler - - (a) 2 Inspect Bonded Doubler - - (b) (a) Do a detailed inspection of the bonded doubler for disbonding adjacent to the area shown in Step 2. Use a wedge made from a material that will not scratch aluminium (Plastic, Phenolic or similar) to check for disbonding along the edge of the doubler. (b) Do a HFEC inspection for cracks in the bonded doubler within 0.25 inch of the doubler edge in the area showns and as given in 737 NDT, Part 6, 51-00-00, Figure 4 or 737 NDT, Part 6, 51-00-00 Figure 23.

**(SHEET 3 OF 3) FIGURE 31: SKIN INSPECTION - LEFT HAND SIDE BETWEEN STA 490 AND STA 500, STRINGER 17L**  Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 204 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT FIGURE 31: SKIN INSPECTION - LEFT HAND SIDE BETWEEN STA 490 AND STA 500, STRINGER 17L** 

EDDY CURRENT INSPECTION AREA S-16L STA 360 S-18L S-20L S-22L S-26L S-14L STA 500A STA 500F

STA 440

S-14L

S-15L

S-16L

S-17L

S-18L

S-19L

S-20L STA 450 STA 460 STA 470 STA 480 STA 490 STA 500 STA 440 STA 500A FWD



### A LAP JOINT UPPER SKIN

LOWER SKIN

FWD UP SEE A



### 737-400 LEFT SIDE

1 SEE B1495707

**(SHEET 1 OF 2) FIGURE 31: SKIN INSPECTION - LEFT HAND SIDE BETWEEN STA 490 AND STA 500, STRINGER 17L**  Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 205 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT**

This Figure applies to Group 4, 7, 11, 16: The step numbers shown below agree with the numbers shown in the circle symbols in the figure. **STEP TASK NAME IDENTIFICATION QTY MORE DATA** 1 Inspect Fuselage Skin - - (a) (a) Do an eddy current inspection for chem-mill cracks as given in 737 NDT, Part 6, 53-30-09 or 737 NDT, Part 6, 53-30-18 or 737 NDT, Part 6, 53-30-19 or 737 NDT, Part 6, 53-30-25. 

### FRAME FRAME
SKIN DOUBLER EDGE OF BONDED

STRINGER

STRINGER

TYPICAL BAY TYPICAL CRACK

TYPICAL CRACK 1



### B1548951

**(SHEET 2 OF 2) FIGURE 32: SKIN INSPECTION - LEFT HAND SIDE BETWEEN STA 727 AND STA 1016**  Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 206 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT FIGURE 32: SKIN INSPECTION - LEFT HAND SIDE BETWEEN STA 727 AND STA 1016** 



### DETAILED AND EDDY CURRENT INSPECTION AREA A SEE

S-7L

S-8L

S-9L

S-10L STA 757 STA 767 STA 777 STA 787 STA 747

B SEE FWD STA 908

S-14L S-10L S-4L S-4R BL 0 STA 1016



### A UPPER SKIN

FWD UP STA 767 STA 757 STA 727 S-9L

1 21504460

**(SHEET 1 OF 2) FIGURE 32: SKIN INSPECTION - LEFT HAND SIDE BETWEEN STA 727 AND STA 1016**  Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 207 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT**

This Figure applies to Group 1: The step numbers shown below agree with the numbers shown in the circle symbols in the figure. **STEP TASK NAME IDENTIFICATION QTY MORE DATA** 1 Inspect Fuselage Skin - - (a) 2 Inspect Fuselage Skin - - (b) (a) Do an external detailed inspection of the fuselage skin for chem-mill cracks. (b) Do an eddy current inspection for chem-mill cracks as given in 737 NDT, Part 6, 53-30-09 or 737 NDT, Part 6, 53-30-18 or 737 NDT, Part 6, 53-30-19 or 737 NDT, Part 6, 53-30-25. 

### FRAME FRAME
SKIN DOUBLER EDGE OF BONDED

STRINGER

STRINGER

TYPICAL BAY TYPICAL CRACK

TYPICAL CRACK 1



### B 21548955

**(SHEET 2 OF 2) FIGURE 33: SKIN INSPECTION - LEFT HAND SIDE BETWEEN STA 360 AND STA 540 AND STA 727**  **AND STA 1016** Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 208 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT FIGURE 33: SKIN INSPECTION - LEFT HAND SIDE BETWEEN STA 360 AND STA 540 AND STA 727 AND**  **STA 1016**



### 737-200 AIRPLANES C SEE B

SEE

A SEE S-14L S-10L S-4R BL S-4L 0

360 STA 540 STA

FWD STA 908

S-14L S-10L S-4L S-4R BL 0 STA 1016

STA 767 STA 757 STA 727 S-9L 490 STA 480 STA

410 STA 390 STA

S-9L S-6L

S-5L

FWD1504461

**(SHEET 1 OF 4) FIGURE 33: SKIN INSPECTION - LEFT HAND SIDE BETWEEN STA 360 AND STA 540 AND STA 727**  **AND STA 1016** Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 209 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT**

DETAILED AND EDDY CURRENT INSPECTION AREA DETAILED AND EDDY CURRENT INSPECTION AREA

S-7L

S-8L

S-9L

S-10L STA 480 STA 490 STA 500 STA 460 S-3L

S-4L

S-5L

S-6L STA 380 STA 390 STA 400 STA 410 STA 370

S-7L STA 420 STA 430

STA 500A



### B UPPER SKIN

FWD UP 

### A UPPER SKIN

FWD UP

1 2 1 2 SEE D

SEE D1504462

**(SHEET 2 OF 4) FIGURE 33: SKIN INSPECTION - LEFT HAND SIDE BETWEEN STA 360 AND STA 540 AND STA 727**  **AND STA 1016** Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 210 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT**

This Figure applies to Group 2, 13: 

### DETAILED AND EDDY CURRENT INSPECTION AREA

FRAME FRAME
SKIN DOUBLER EDGE OF BONDED

STRINGER

STRINGER

TYPICAL BAY TYPICAL CRACK

TYPICAL CRACK

S-7L

S-8L

S-9L

S-10L STA 757 STA 767 STA 787 STA 747



### C UPPER SKIN

FWD UP 1 2 SEE D

1



### D 21504463

**(SHEET 3 OF 4) FIGURE 33: SKIN INSPECTION - LEFT HAND SIDE BETWEEN STA 360 AND STA 540 AND STA 727**  **AND STA 1016** Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 211 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT** The step numbers shown below agree with the numbers shown in the circle symbols in the figure. **STEP TASK NAME IDENTIFICATION QTY MORE DATA** 1 Inspect Fuselage Skin - - (a) 2 Inspect Fuselage Skin - - (b) (a) Do an external detailed inspection of the fuselage skin for chem-mill cracks. (b) Do an external eddy current inspection for chem-mill cracks as given in 737 NDT, Part 6, 53-30-09 or 737 NDT, Part 6, 53-30-18 or 737 NDT, Part 6, 53-30-19 or 737 NDT, Part 6, 53-30-25.

**(SHEET 4 OF 4) FIGURE 34: SKIN INSPECTION - LEFT AND RIGHT SIDE BETWEEN STA 360 AND STA 540**  Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 212 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT FIGURE 34: SKIN INSPECTION - LEFT AND RIGHT SIDE BETWEEN STA 360 AND STA 540** 

B SEE

A SEE C SEE

G SEE
F SEE

D SEE E SEE



### 737-300 AIRPLANES FWD S-14R

S-10R S-4L BL S-4R 0 360 STA

540 STA 500 STA

380 STA

S-6R FWD STA 500C 520 STA

STA 500C STA 500B STA 500 STA 480
STA 460 STA 380 STA 360 540 STA

S-14L S-10L S-4R

BL S-4L 0 S-6L1504464

**(SHEET 1 OF 6) FIGURE 34: SKIN INSPECTION - LEFT AND RIGHT SIDE BETWEEN STA 360 AND STA 540**  Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 213 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT**

DETAILED AND EDDY CURRENT INSPECTION AREA DETAILED AND EDDY CURRENT INSPECTION AREA S-6L

S-7L

S-8L

S-9L STA 370 STA 380 STA 360

S-10L

S-6L

S-7L

S-8L

S-9L STA 500B STA 500A STA 500

S-10L STA 500C



### B FWD UP 

### A FWD UP 1 2 SEE H

1 2 SEE H1504472

**(SHEET 2 OF 6) FIGURE 34: SKIN INSPECTION - LEFT AND RIGHT SIDE BETWEEN STA 360 AND STA 540**  Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 214 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT**

DETAILED AND EDDY CURRENT INSPECTION AREA

DETAILED AND EDDY CURRENT INSPECTION AREA S-6L

S-7L

S-8L

S-9L STA 500D STA 500C

S-10L

S-6R

S-7R

S-8R

S-9R STA 360 STA 380

S-10R STA 520

STA 370 STA 540

UP
FWD


### D C FWD UP 1 2 SEE H

1 2 SEE H1504475

**(SHEET 3 OF 6) FIGURE 34: SKIN INSPECTION - LEFT AND RIGHT SIDE BETWEEN STA 360 AND STA 540**  Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 215 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT**

DETAILED AND EDDY CURRENT INSPECTION AREA

DETAILED AND EDDY CURRENT INSPECTION AREA STA 500A STA 500B S-6R

S-7R

S-8R

S-9R STA 460 STA 480

S-10R

STA 500 STA 470

S-6R

S-7R

S-8R

S-9R

S-10R STA 500C UP
FWD

UP
FWD 

### E UPPER SKIN



### F UPPER SKIN 1 2

1 2 SEE H SEE H1504477

**(SHEET 4 OF 6) FIGURE 34: SKIN INSPECTION - LEFT AND RIGHT SIDE BETWEEN STA 360 AND STA 540**  Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 216 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT**

This Figure applies to Group 3, 9-10, 14-15, 18, 21: 

### DETAILED AND EDDY CURRENT INSPECTION AREA
FRAME FRAME
SKIN DOUBLER EDGE OF BONDED

STRINGER

STRINGER

TYPICAL BAY TYPICAL CRACK

TYPICAL CRACK STA 520 STA 540 STA 500D

S-6R

S-7R

S-8R

S-9R

S-10R

S-5R S-4R STA 500C

UP
FWD 

### G UPPER SKIN 1 2 SEE H

1



### H 21504478

**(SHEET 5 OF 6) FIGURE 34: SKIN INSPECTION - LEFT AND RIGHT SIDE BETWEEN STA 360 AND STA 540**  Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 217 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT** The step numbers shown below agree with the numbers shown in the circle symbols in the figure. **STEP TASK NAME IDENTIFICATION QTY MORE DATA** 1 Inspect Fuselage Skin - - (a) 2 Inspect Fuselage Skin - - (b) (a) Do an external detailed inspection of the fuselage skin for chem-mill cracks. (b) Do an external eddy current inspection for chem-mill cracks as given in 737 NDT, Part 6, 53-30-09 or 737 NDT, Part 6, 53-30-18 or 737 NDT, Part 6, 53-30-19 or 737 NDT, Part 6, 53-30-25.

**(SHEET 6 OF 6) FIGURE 35: SKIN INSPECTION - LEFT AND RIGHT SIDE BETWEEN STA 727 AND 1016**  Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 218 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT FIGURE 35: SKIN INSPECTION - LEFT AND RIGHT SIDE BETWEEN STA 727 AND 1016** 



### 737-300 AIRPLANES A SEE B SEE

C SEE

D SEE

FWD FWD STA 727C S-14L S-10L S-4L S-4R BL 0 STA 1016 S-3L S-7L

STA 727E STA 767 STA 827

STA 727

S-14R

S-10R S-4R S-4L BL 0
S-3R S-7R STA 1016

STA 727 STA 908 STA 967

STA 867 STA 827 S-1R1504498

**(SHEET 1 OF 4) FIGURE 35: SKIN INSPECTION - LEFT AND RIGHT SIDE BETWEEN STA 727 AND 1016**  Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 219 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT**

DETAILED AND EDDY CURRENT INSPECTION AREA

DETAILED AND EDDY CURRENT INSPECTION AREA S-7L

S-8L

S-9L STA 787 STA 807 STA 767

S-3L

S-4L

S-5L

S-6L STA 727D STA 727E STA 727C S-2L

S-6L S-5L S-4L STA 827



### B UPPER SKIN

FWD UP 

### A UPPER SKIN

FWD UP 1 2 SEE E

1 2 SEE E1504502

**(SHEET 2 OF 4) FIGURE 35: SKIN INSPECTION - LEFT AND RIGHT SIDE BETWEEN STA 727 AND 1016**  Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 220 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT**

DETAILED AND EDDY CURRENT INSPECTION AREA DETAILED AND EDDY CURRENT INSPECTION AREA S-5R

S-6R

S-7R STA 996 STA 977 STA 1016

S-2R

S-3R

S-4R STA 847 STA 827 STA 867 S-1R S-4R S-3R S-2R

S-8R STA 986.5 STA 967 STA 1006

STA 857 STA 837 

### C UPPER SKIN

FWD UP



### D UPPER SKIN 1 2 SEE E

1 2 SEE E

FWD UP1504508

**(SHEET 3 OF 4) FIGURE 35: SKIN INSPECTION - LEFT AND RIGHT SIDE BETWEEN STA 727 AND 1016**  Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 221 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT**

This Figure applies to Group 3, 9-10, 14-15, 18, 21: The step numbers shown below agree with the numbers shown in the circle symbols in the figure. **STEP TASK NAME IDENTIFICATION QTY MORE DATA** 1 Inspect Fuselage Skin - - (a) 2 Inspect Fuselage Skin - - (b) (a) Do an external detailed inspection of the fuselage skin for chem-mill cracks. (b) Do an external eddy current inspection for chem-mill cracks as given in 737 NDT, Part 6, 53-30-09 or 737 NDT, Part 6, 53-30-18 or 737 NDT, Part 6, 53-30-19 or 737 NDT, Part 6, 53-30-25. FRAME FRAME
SKIN DOUBLER EDGE OF BONDED

STRINGER

STRINGER

TYPICAL BAY TYPICAL CRACK

TYPICAL CRACK 2 1



### E1853142

**(SHEET 4 OF 4) FIGURE 36: SKIN INSPECTION - LEFT SIDE BETWEEN STA 360 AND STA 540**  Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 222 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT FIGURE 36: SKIN INSPECTION - LEFT SIDE BETWEEN STA 360 AND STA 540** 

DETAILED AND EDDY CURRENT INSPECTION AREA A SEE


### 737-400 AIRPLANES

S-8L

S-9L

S-10L

S-7L S-6L S-5L S-4L STA 360 STA 370 STA 380 STA 390 STA 400 S-14L S-10L S-4R BL S-4L 0

360 STA 540 STA

400 STA S-8L

FWD



### A UPPER SKIN

FWD UP 1 2 SEE B1504861

**(SHEET 1 OF 2) FIGURE 36: SKIN INSPECTION - LEFT SIDE BETWEEN STA 360 AND STA 540**  Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 223 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT**

This Figure applies to Group 4, 11, 16: The step numbers shown below agree with the numbers shown in the circle symbols in the figure. **STEP TASK NAME IDENTIFICATION QTY MORE DATA** 1 Inspect Fuselage Skin - - (a) 2 Inspect Fuselage Skin - - (b) (a) Do an external detailed inspection of the fuselage skin for chem-mill cracks. (b) Do an external eddy current inspection for chem-mill cracks as given in 737 NDT, Part 6, 53-30-09 or 737 NDT, Part 6, 53-30-18 or 737 NDT, Part 6, 53-30-19 or 737 NDT, Part 6, 53-30-25. 

### FRAME FRAME
SKIN DOUBLER EDGE OF BONDED

STRINGER

STRINGER

TYPICAL BAY TYPICAL CRACK

2 1



### B1549320

**(SHEET 2 OF 2) FIGURE 37: SKIN INSPECTION - LEFT SIDE BETWEEN STA 360 AND STA 540**  Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 224 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT FIGURE 37: SKIN INSPECTION - LEFT SIDE BETWEEN STA 360 AND STA 540** 

DETAILED AND EDDY CURRENT INSPECTION AREA 

### 737-500 AIRPLANES

S-8L

S-9L

S-10L

S-7L S-6L S-5L S-4L STA 428A+10 STA 428B STA 428B+10 STA 520 A SEE



### A UPPER SKIN

FWD UP S-14L S-10L S-4R BL S-4L 0

360 STA 540 STA

STA 428B

S-7L

FWD 520 STA

1 2 SEE B1504526

**(SHEET 1 OF 2) FIGURE 37: SKIN INSPECTION - LEFT SIDE BETWEEN STA 360 AND STA 540**  Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 225 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT**

This Figure applies to Group 5, 12, 17, 19-20: The step numbers shown below agree with the numbers shown in the circle symbols in the figure. **STEP TASK NAME IDENTIFICATION QTY MORE DATA** 1 Inspect Fuselage Skin - - (a) 2 Inspect Fuselage Skin - - (b) (a) Do an external detailed inspection for chem-mill cracks. (b) Do an external eddy current inspection for chem-mill cracks as given in 737 NDT, Part 6, 53-30-09 or 737 NDT, Part 6, 53-30-18 or 737 NDT, Part 6, 53-30-19 or 737 NDT, Part 6, 53-30-25. 

### FRAME FRAME
SKIN DOUBLER EDGE OF BONDED

STRINGER

STRINGER

TYPICAL BAY TYPICAL CRACK 2 1



### B1549322

**(SHEET 2 OF 2) FIGURE 38: TIME LIMITED REPAIR - CHE**  **M-MILL CRACKS - NOT LOCATED AT LAP JOINTS** Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 226 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT FIGURE 38: TIME LIMITED REPAIR - CH**  **EM-MILL CRACKS - NOT LOCATED AT LAP JOINTS**

TYPICAL AND INSTALLATION FOR PART FABRICATION

TYPICAL 

### PART FABRICATION AND INSTALLATION (TYPICAL) STRINGER

(TYPICAL) 0.75 MINIMUM (IF PRESENT) SHEAR TIE (TYPICAL) STA STA (TYPICAL) STAGGER FASTENERS COMMON TO TEARSTRAPS 2X R 0.50 TYPICAL CRACK 

### TYPICAL CRACK LOCATION,
AND SKIN TRIM INSPECTION, FASTENER REMOVAL, (TYPICAL) STRINGER STA (TYPICAL) STA (TYPICAL) STA (TYPICAL) STA (TYPICAL)

4 3 2

7 5 6 9

8 5



### A A SEE 1 11521704

**(SHEET 1 OF 4) FIGURE 38: TIME LIMITED REPAIR - CHEM-MILL CRACKS - NOT LOCATED AT LAP JOINTS**  Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 227 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT** The step numbers shown below agree with the numbers shown in the circle symbols in the figure. **NOTE:** 1. This repair cannot be used if the fasteners that exist are larger than 3/16 inch diameter. 2. This repair cannot be used in areas where hi-locks, lockbolts, or bolts were installed in production. If these fasteners are common to the repair, install a permanent repair. 3. Install fasteners using the fastener pattern that exists as a guide in the fore and aft direction. Use this figure to determine fastener pitch in the circumferential direction. Make the distance between fasteners 0.93-1.10 inch. Maintain a minimum edge margin of 2 times the fastener diameter for new fastener locations and 1.7 times the fastener diameter for fastener locations that exist. 4. In the typical repair shown in this figure, the left side tear strap location shows a typical shear tie fastener pattern. The right side tear strap location shows a typical non-shear tied fastener pattern. The detail may be different, depending on the specific repair location. Use this figure as a guide, maintaining the same number and pattern of fasteners around the cutout, and common to the tear straps or shear ties. 5. Do not use this repair common to fuselage cutouts, lap joints or butt joints. 6. Trim skin as shown, regardless of crack length provided the crack is contained within the trim-out area. Ensure a minimum 2D edge margin is maintained when trimming. 7. The trim line cannot enter the radius of the bonded doubler at the tear straps. 8. Maintain a 63 micro-inch or better surface finish on all trimmed structure. 9. Do not install this repair if other chem-mill cracks exist within 20 inches of this chem-mill crack. **STEP TASK NAME IDENTIFICATION QTY MORE DATA** 1 Inspect Fuselage Skin Detailed Inspection - (a)(b) 2 Remove / Discard Fasteners - - In the area that will be common to the repair.
3 Trim Skin - - (c) Remove Trimmed Skin - 1 -

4 Apply Chemical Film Treatment Alodine or Iridite - (d) Primer BMS 10-11, Type 1 - 1 coat. (d)
**NOTE:** Size the repair parts to maintain a minimum edge margin of two times the fastener diameter at new fastener locations, and of 1.7 times the fastener diameter at existing fastener locations. Maintain a minimum corner radius of 0.5 inch.

5 Measure Skin Thickness Common To The Cutout - 1 For required doubler thickness. Make Repair Doubler 2024-T3 clad sheet 1 See Table 1 (e)

**(SHEET 2 OF 4) FIGURE 38: TIME LIMITED REPAIR - CHE**  **M-MILL CRACKS - NOT LOCATED AT LAP JOINTS** Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 228 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT**

6 Apply Chemical Film Treatment Alodine or Iridite - - Primer BMS 10-11, Type 1 - 1 coat.

**NOTE:** Shim all gaps from 0.01 - 0.04 inch prior to fastener installation. Contact Boeing for instructions for gaps greater than 0.04 inch. Do not install shims between the skin and doubler. Clean the faying surfaces of the fuselage skin (Refer to SOPM 20-30-03 for cleaning requirements) and repair parts as given in 737-300 SRM 51-20-05 or 737-400 SRM 51-20-05 or 737-500 SRM 51-20-05, Note 2, prior to the application of sealant.

7 Install Repair Doubler - 1 With BMS 5-95 faying surface sealant.Refer to SOPM 20-50-19.

8 Apply Fillet Seal - - Use BMS 5-95 sealant around the edges of the repair parts, or ensure proper edge sealing per SOPM 20-50-19. 9 Apply Finish - - To the repaired area to match adjacent structure. (a) Of the skin in the area of chem-milled step cracks. (b) Of the skin in the area of the repair for corrosion or disbonded doublers. Look for bulging of the skin. If corrosion or disbond is found, contact Boeing. If no corrosion or disbond is found, continue with the repair.

(c) The trim-out must be as shown to eliminate undetected cracks. The trim-out must be a minimum of 0.5 inch beyond the visible ends of the crack. If this is not possible then repair as given in 737-100/200 SRM 53-30-3 Figure 48, or 737-300 SRM 53-00-01 Figure 201, Repair 31, or 737-400 SRM 53-00-01 Figure 201, Repair 31, or 737-500 SRM 53-00-01 Figure 201, Repair 31, as applicable. (d) To all cut edges of the skin. (e) Pre-form to match the contour of the fuselage.

**Table 1 - Repair Doubler Thickness Skin Thickness (inches) Repair Doubler Thickness (inches)**  0.032 or 0.036 0.040 0.040 0.050 0.050 or greater. Contact Boeing for repair instructions.
**BLIND FASTENER INSTALLATION** Existing Rivets HOLE DIAMETER INSTALL NOTES 0.176 - 0.180 BACR15FR5E( )R (a)(b)(i) 0.205 - 0.209 BACR15FR6E( )R (a)(c)(d)(i)(e) New Fasteners HOLE DIAMETER INSTALL NOTES 0.176 - 0.180 BACR15FR5E( )R (f)(g)(h)(i) **STEP TASK NAME IDENTIFICATION QTY MORE DATA**

**(SHEET 3 OF 4) FIGURE 38: TIME LIMITED REPAIR - CHEM-MILL CRACKS - NOT LOCATED AT LAP JOINTS**  Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 229 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT**

(a) Install with a repair washer as given in 737-300/400/500 SRM 51-40-08. (b) If the original fastener was 5/32 inch diameter. (c) Optional if it is necessary to make the hole larger to remove damage. (d) If the original fastener was 3/16 inch diameter. (e) Maintain a minimum edge margin at the shear tie of 1.5 times the fastener diameter. If this edge margin cannot be maintained, contact Boeing. (f) Use caution when locating these fasteners common to the tearstraps. Maintain a minimum edge margin of 1.7 times the fastener diameter from the edge of the tearstrap. (g) Space the fasteners 0.93 to 1.10 inches. (h) At new fastener locations common to tearstrap minimum spacing is 0.75 inch. (i) NAS1738E( )-( ) optional to BACR15FR( )E( )R **BLIND FASTENER INSTALLATION**

**(SHEET 4 OF 4) FIGURE 39: INSPECTION FOR VERTICAL CRACKS AT CHEM-MILL LINES OF FUSELAGE SKIN**  Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 230 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT FIGURE 39: INSPECTION FOR VERTICAL CRAC**  **KS AT CHEM-MILL LINES OF FUSELAGE SKIN**

S-10R

S-19R S-17R STA 360 STA 540 STA 727 STA 908 STA 460

STA 312

B SEE SEE C SEE A SEE C SEE C SEE C



### 737-300 AIRPLANES 1 2 1 7

1 6

1 5

1 4
1 31523878

**(SHEET 1 OF 4) FIGURE 39: INSPECTION FOR VERTICAL CRACKS AT CHEM-MILL LINES OF FUSELAGE SKIN**  Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 231 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT**

INSPECTION AREA TYPICAL CRACK INSPECTION AREA TYPICAL CRACK

UP
FWD S-17R UP
FWD S-19R

S-20R LOWER SKIN PANEL LAP JOINT UPPER SKIN PANEL



### B STA 460 STA 469.90

EDGE OF SKIN 

### A STA 312

2

4 1

11523875

**(SHEET 2 OF 4) FIGURE 39: INSPECTION FOR VERTICAL CRACKS AT CHEM-MILL LINES OF FUSELAGE SKIN**  Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 232 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT**

This Figure applies to Group 3, 9-10, 14-15: 

### INSPECTION AREA TYPICAL CRACK

UP
FWD STRINGER

STRINGER

STRINGER

STRINGER

STRINGER



### C BUTT JOINT LAP JOINT UPPER AFT SKIN PANEL UPPER FORWARD SKIN PANEL



### TYPICAL CIRCUMFERENTIAL BUTT SPLICE 3 1 5 6 71523876

**(SHEET 3 OF 4) FIGURE 39: INSPECTION FOR VERTICAL CRACKS AT CHEM-MILL LINES OF FUSELAGE SKIN**  Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 233 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT** The step numbers shown below agree with the numbers shown in the circle symbols in the figure. **STEP TASK NAME IDENTIFICATION QTY MORE DATA** 1 Inspect Skin Panel - - (a) 2 Inspect Skin Panel - - (b) 3 Inspect Skin Panel - - (c) 4 Inspect Skin Panel - - (d) 5 Inspect Skin Panel - - (e) 6 Inspect Skin Panel - - (f) 7 Inspect Skin Panel - - (g) (a) Do an external detailed inspection of the fuselage skin for chem-mill cracks. (b) Do an external Low Frequency Eddy Current (LFEC) or Magneto Optical Imaging (MOI) or C-Scan inspection at STA 312 below S-19R for vertical subsurface skin cracks as given in 737 NDT, Part 6, 53-30-09 or 737 NDT, Part 6, 53-30-18 or 737 NDT, Part 6, 53-30-19 or 737 NDT, Part 6, 53-30-25. (c) Do an external LFEC or MOI or C-Scan inspection at the circumferential butt splice STA 360 between S-10L and S-10R for vertical subsurface skin cracks as given in 737 NDT, Part 6, 53-30-09 or 737 NDT, Part 6, 53-30-18 or 737 NDT, Part 6, 53-30-19 or 737 NDT, Part 6, 53-30-25. (d) Do an external LFEC or MOI or C-Scan inspection at STA 460 below S-17R for vertical subsurface skin cracks as given in 737 NDT, Part 6, 53-30-09 or 737 NDT, Part 6, 53-30-18 or 737 NDT, Part 6, 53-30-19 or 737 NDT, Part 6, 53-30-25. (e) Do an external LFEC or MOI or C-Scan inspection at the circumferential butt splice STA 540 between S-10L and S-10R for vertical subsurface skin cracks as given in 737 NDT, Part 6, 53-30-09 or 737 NDT, Part 6, 53-30-18 or 737 NDT, Part 6, 53-30-19 or 737 NDT, Part 6, 53-30-25. (f) Do an external LFEC or MOI or C-Scan inspection at the circumferential butt splice STA 727 between S-10L and S-10R for vertical subsurface skin cracks as given in 737 NDT, Part 6, 53-30-09 or 737 NDT, Part 6, 53-30-18 or 737 NDT, Part 6, 53-30-19 or 737 NDT, Part 6, 53-30-25. (g) Do an external LFEC or MOI or C-Scan inspection at the circumferential butt splice STA 908 between S-10L and S-10R for vertical subsurface skin cracks as given in 737 NDT, Part 6, 53-30-09 or 737 NDT, Part 6, 53-30-18 or 737 NDT, Part 6, 53-30-19 or 737 NDT, Part 6, 53-30-25.

**(SHEET 4 OF 4) FIGURE 40: INSPECTION FOR VERTICAL CRACKS AT CHEM-MILL LINES OF FUSELAGE SKIN**  Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 234 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT FIGURE 40: INSPECTION FOR VERTICAL CRAC**  **KS AT CHEM-MILL LINES OF FUSELAGE SKIN**



### S-10R

S-19R S-17R STA 360

STA 540 STA 727 STA 908 STA 460

STA 312

B SEE SEE C SEE A SEE C SEE C SEE C



### 737-500 AIRPLANES 737-200 MODELS ARE SIMILAR 1 2 1 3 1 4 1 5 1 6 1 71523889

**(SHEET 1 OF 4) FIGURE 40: INSPECTION FOR VERTICAL CRACKS AT CHEM-MILL LINES OF FUSELAGE SKIN**  Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 235 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT**

INSPECTION AREA TYPICAL CRACK INSPECTION AREA TYPICAL CRACK

UP
FWD S-17R UP
FWD S-19R

S-20R LOWER SKIN PANEL LAP JOINT UPPER SKIN PANEL



### B STA 460 STA 469.90

EDGE OF SKIN 

### A STA 312

2 1

4 11523880

**(SHEET 2 OF 4) FIGURE 40: INSPECTION FOR VERTICAL CRACKS AT CHEM-MILL LINES OF FUSELAGE SKIN**  Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 236 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT**

This Figure applies to Group 2, 5, 12-13, 17: 

### INSPECTION AREA TYPICAL CRACK

UP
FWD STRINGER

STRINGER

STRINGER

STRINGER

STRINGER



### C BUTT JOINT LAP JOINT UPPER AFT SKIN PANEL UPPER FORWARD SKIN PANEL



### TYPICAL CIRCUMFERENTIAL BUTT SPLICE 3 1 6 5 71523879

**(SHEET 3 OF 4) FIGURE 40: INSPECTION FOR VERTICAL CRACKS AT CHEM-MILL LINES OF FUSELAGE SKIN**  Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 237 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT** The step numbers shown below agree with the numbers shown in the circle symbols in the figure. **STEP TASK NAME IDENTIFICATION QTY MORE DATA** 1 Inspect Skin Panel - - (a) 2 Inspect Skin Panel - - (b) 3 Inspect Skin Panel - - (c) 4 Inspect Skin Panel - - (d) 5 Inspect Skin Panel - - (e) 6 Inspect Skin Panel - - (f) 7 Inspect Skin Panel - - (g) (a) Do an external detailed inspection of the fuselage skin for chem-mill cracks. (b) Do an external Low Frequency Eddy Current (LFEC) or Magneto Optical Imaging (MOI) or C-Scan inspection at STA 312 below S-19R for vertical subsurface skin cracks as given in 737 NDT, Part 6, 53-30-09 or 737 NDT, Part 6, 53-30-18 or 737 NDT, Part 6, 53-30-19 or 737 NDT, Part 6, 53-30-25. (c) Do an external LFEC or MOI or C-Scan inspection at the circumferential butt splice STA 360 between S-10L and S-10R for vertical subsurface skin cracks as given in 737 NDT, Part 6, 53-30-09 or 737 NDT, Part 6, 53-30-18 or 737 NDT, Part 6, 53-30-19 or 737 NDT, Part 6, 53-30-25. (d) Do an external LFEC or MOI or C-Scan inspection at STA 460 below S-17R for vertical subsurface skin crack as given in 737 NDT, Part 6, 53-30-09 or 737 NDT, Part 6, 53-30-18 or 737 NDT, Part 6, 53-30-19 or 737 NDT, Part 6, 53-30-25. (e) Do an external LFEC or MOI or C-Scan inspection at the circumferential butt splice STA 540 between S-10L and S-10R for vertical subsurface skin cracks as given in 737 NDT, Part 6, 53-30-09 or 737 NDT, Part 6, 53-30-18 or 737 NDT, Part 6, 53-30-19 or 737 NDT, Part 6, 53-30-25. (f) Do an external LFEC or MOI or C-Scan inspection at the circumferential butt splice STA 727 between S-10L and S-10R for vertical subsurface skin cracks as given in 737 NDT, Part 6, 53-30-09 or 737 NDT, Part 6, 53-30-18 or 737 NDT, Part 6, 53-30-19 or 737 NDT, Part 6, 53-30-25. (g) Do an external LFEC or MOI or C-Scan inspection at the circumferential butt splice STA 908 between S-10L and S-10R for vertical subsurface skin cracks as given in 737 NDT, Part 6, 53-30-09 or 737 NDT, Part 6, 53-30-18 or 737 NDT, Part 6, 53-30-19 or 737 NDT, Part 6, 53-30-25.

**(SHEET 4 OF 4) FIGURE 41: SKIN INSPECTIONS IN THE LOWER LOBE AREA**  Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 238 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT FIGURE 41: SKIN INSPECTIONS IN THE LOWER LOBE AREA** 

S-4L S-4R S-19R S-26R 1016 STA 908 STA 727 STA STA STA 360 540

BL 0 BL 0

S-25L S-20L S-14L S-10L S-10R S-14R S-20R

S-4L

S-10L
S-14L

S-19L

S-24L S-4R S-10R S-14R S-19R S-24R S-25R



### 737-200 AIRPLANE INSPECTION AREA SEE A

SEE A TYPICAL1549324

**(SHEET 1 OF 3) FIGURE 41: SKIN INSPECTIONS IN THE LOWER LOBE AREA**  Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 239 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT**

This Figure applies to Group 13: CRACKS TYPICAL

SKIN LOWER TYPICAL CRACK UPPER DOUBLER UPPER SKIN



### A C/L FRAME

1

INSPECTION

TYPICAL

AREA 1

C/L STRINGER1549325

**(SHEET 2 OF 3) FIGURE 41: SKIN INSPECTIONS IN THE LOWER LOBE AREA**  Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 240 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT** The step numbers shown below agree with the numbers shown in the circle symbols in the figure. **STEP TASK NAME IDENTIFICATION QTY MORE DATA** 1 Inspect Fuselage Skin - - (a) (a) Do a detailed or general visual inspection for chem-mill cracks. If general visual inspections are accomplished in lieu of detailed inspections, then repeat inspection intervals are reduced. Refer to Paragraph 1.E., Compliance for repeat inspection interval requirements.

**(SHEET 3 OF 3) FIGURE 42: FUSELAGE WINDOW BELT AREA INSPECTION**  Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 241 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT FIGURE 42: FUSELAGE WINDOW BELT AREA INSPECTION** 



### 737-300 AIRPLANES RIGHT SIDE OPPOSITE LEFT SIDE SHOWN A SEE

S-14L S-10L S-4R

BL S-4L 0

360 STA 540 STA1574948

**(SHEET 1 OF 3) FIGURE 42: FUSELAGE WINDOW BELT AREA INSPECTION**  Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 242 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT**

This Figure applies to Group 3, 9-10, 14-15, 18, 21: TYPICAL CRACK

INSPECTION AREA S-12 520 STA 500D+10

STA STA 500D

FWD 2 1



### A 2 11574949

**(SHEET 2 OF 3) FIGURE 42: FUSELAGE WINDOW BELT AREA INSPECTION**  Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 243 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT** The step numbers shown below agree with the numbers shown in the circle symbols in the figure.

**STEP TASK NAME IDENTIFICATION QTY MORE DATA** 1 Inspect Fuselage Skin - - (a) 2 Inspect Fuselage Skin - - (b) (a) Do an external detailed inspection of the fuselage skin for chem-mill cracks. (b) Do an external eddy current inspection for chem-mill cracks as given in 737 NDT, Part 6, 53-30-09 or 737 NDT, Part 6, 53-30-18 or 737 NDT, Part 6, 53-30-19 or 737 NDT, Part 6, 53-30-25.

**(SHEET 3 OF 3) FIGURE 43: FUSELAGE WINDOW BELT AREA INSPECTION**  Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 244 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT FIGURE 43: FUSELAGE WINDOW BELT AREA INSPECTION** 



### 737-400 AIRPLANES RIGHT SIDE OPPOSITE LEFT SIDE SHOWN A SEE B SEE STA 360 S-4L S-4R

0 BL 540 STA

S-10L
S-14L1574951

**(SHEET 1 OF 4) FIGURE 43: FUSELAGE WINDOW BELT AREA INSPECTION**  Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 245 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT**

TYPICAL CRACK

INSPECTION AREA S-12 500F STA 500E+10

STA STA 500E

S-14 S-10

S-13 S-11

C/L

FWD 2 1



### A1574953

**(SHEET 2 OF 4) FIGURE 43: FUSELAGE WINDOW BELT AREA INSPECTION**  Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 246 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT**

This Figure applies to Group 4, 11, 16:

TYPICAL CRACK

INSPECTION AREA S-12L 520 STA 500G+10

STA STA 500G

S-14L S-10L

S-13L S-11L

C/L

FWD 2 1



### B1574954

**(SHEET 3 OF 4) FIGURE 43: FUSELAGE WINDOW BELT AREA INSPECTION**  Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 247 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT** The step numbers shown below agree with the numbers shown in the circle symbols in the figure. **STEP TASK NAME IDENTIFICATION QTY MORE DATA** 1 Inspect Fuselage Skin - - (a) 2 Inspect Fuselage Skin - - (b) (a) Do an external detailed inspection of the fuselage skin for chem-mill cracks. (b) Do an external eddy current inspection for chem-mill cracks as given in 737 NDT, Part 6, 53-30-09 or 737 NDT, Part 6, 53-30-18 or 737 NDT, Part 6, 53-30-19 or 737 NDT, Part 6, 53-30-25.

**(SHEET 4 OF 4) FIGURE 44: FUSELAGE WINDOW BELT AREA INSPECTION**  Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 248 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT FIGURE 44: FUSELAGE WINDOW BELT AREA INSPECTION** 



### 737-500 AIRPLANES RIGHT SIDE OPPOSITE LEFT SIDE SHOWN STA 540

STA 360 0 S-4L BL S-4R

S-10L
S-14L A

SEE1574955

**(SHEET 1 OF 3) FIGURE 44: FUSELAGE WINDOW BELT AREA INSPECTION**  Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 249 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT**

This Figure applies to Group 5, 12, 17, 19-20: TYPICAL CRACK

INSPECTION AREA S-12 520 STA 500D+10

STA STA 500D

FWD 2 1



### A 2 11574956

**(SHEET 2 OF 3) FIGURE 44: FUSELAGE WINDOW BELT AREA INSPECTION**  Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 250 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT** The step numbers shown below agree with the numbers shown in the circle symbols in the figure. **STEP TASK NAME IDENTIFICATION QTY MORE DATA** 1 Inspect Fuselage Skin - - (a) 2 Inspect Fuselage Skin - - (b) (a) Do an external detailed inspection of the fuselage skin for chem-mill cracks. (b) Do an external eddy current inspection for chem-mill cracks as given in 737 NDT, Part 6, 53-30-09 or 737 NDT, Part 6, 53-30-18 or 737 NDT, Part 6, 53-30-19 or 737 NDT, Part 6, 53-30-25.

**(SHEET 3 OF 3) FIGURE 45: CROWN AREA SKIN INSPECTIONS**  Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 251 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT FIGURE 45: CROWN AREA SKIN INSPECTIONS** 



### 737-300 AIRPLANES RIGHT SIDE OPPOSITE LEFT SIDE SHOWN 1 3 2 A SEE

1 2

FWD 727A+10 STA

727 STA 928 STA

908 STA

S-14L S-10L S-4L S-14L S-10L

S-4R

540 STA BL 0 1016 STA S-4R

BL S-4L 0

360 STA 540 STA

INSPECTION AREA FOR TYPICAL

587 STA 664 STA 727E STA1652902

**(SHEET 1 OF 3) FIGURE 45: CROWN AREA SKIN INSPECTIONS**  Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 252 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT**

This Figure applies to Group 18, 21: 

### UPPER DOUBLER

SKIN LOWER

INSPECTION AREA TYPICAL CRACK

UPPER SKIN TYPICAL CRACK

1 2



### A 3

10.00 C/L FRAME

UP
INBD SKIN UPPER

SKIN LOWER 

### A A

TYPICAL

AREA INSPECTION C/L STRINGER



### A-A CRACK

STRINGER1652903

**(SHEET 2 OF 3) FIGURE 45: CROWN AREA SKIN INSPECTIONS**  Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 253 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT** The step numbers shown below agree with the numbers shown in the circle symbols in the figure.

**STEP TASK NAME IDENTIFICATION QTY MORE DATA** 1 Inspect Fuselage Skin - - (a) 2 Inspect Fuselage Skin - - (b) 3 Inspect Fuselage Skin - - (c) (a) Do an external detailed inspection of the fuselage skin for chem-mill cracks. (b) Do an external eddy current inspection for chem-mill cracks as given in 737 NDT, Part 6, 53-30-09 or 737 NDT, Part 6, 53-30-18 or 737 NDT, Part 6, 53-30-19 or 737 NDT, Part 6, 53-30-25. (c) Do a detailed or general visual inspection of the non-lap-splice areas from STA 360 to STA 540 between S-10L to S-10R, from STA 727 to 727E between S-4L to S-4R, and from STA 727E to STA 1016 between S-10L to S-10R for horizontal cracks at the chem-mill lines. **NOTE:** If general visual inspections are accomplished in lieu of detailed inspections, then repeat inspection intervals are reduced. Refer to Paragraph 1.E., Compliance for repeat inspection interval requirements.

**(SHEET 3 OF 3) FIGURE 46: CROWN AREA SKIN INSPECTIONS**  Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 254 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT FIGURE 46: CROWN AREA SKIN INSPECTIONS** 



### 737-500 AIRPLANES RIGHT SIDE OPPOSITE LEFT SIDE SHOWN A SEE

3 1 2

1 2
FWD STA 928

727A+10 STA FOR TYPICAL INSPECTION AREA STA 540

STA 360 0 S-4L BL S-4R

STA STA

908 1016
0 BL

STA

STA 540 727 S-4R S-10L

S-14L

S-4L

S-10L S-14L

587 STA 664 STA STA 727C1652910

**(SHEET 1 OF 3) FIGURE 46: CROWN AREA SKIN INSPECTIONS**  Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 255 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT**

This Figure applies to Group 19-20: 

### UPPER DOUBLER

SKIN LOWER

INSPECTION AREA TYPICAL CRACK

UPPER SKIN TYPICAL CRACK



### A 1 2 3

TYPICAL LAP JOINT
AREA INSPECTION 10.00 C/L FRAME

UP
INBD SKIN UPPER

SKIN LOWER 

### A A

C/L STRINGER



### A-A CRACK

STRINGER1652912

**(SHEET 2 OF 3) FIGURE 46: CROWN AREA SKIN INSPECTIONS**  Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 256 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT** The step numbers shown below agree with the numbers shown in the circle symbols in the figure.

**STEP TASK NAME IDENTIFICATION QTY MORE DATA** 1 Inspect Fuselage Skin - - (a) 2 Inspect Fuselage Skin - - (b) 3 Inspect Fuselage Skin - - (c) (a) Do an external detailed inspection of the fuselage skin for chem-mill cracks. (b) Do an external eddy current inspection for chem-mill cracks as given in 737 NDT, Part 6, 53-30-09 or 737 NDT, Part 6, 53-30-18 or 737 NDT, Part 6, 53-30-19 or 737 NDT, Part 6, 53-30-25. (c) Do a detailed or general visual inspection of the non-lap-splice areas from STA 360 to STA 540 between S-10L to S-10R, from STA 727 to 727C between S-4L to S-4R, and from STA 727C to STA 1016 between S-10L to S-10R for horizontal cracks at the chem-mill lines. **NOTE:** If general visual inspections are accomplished in lieu of detailed inspections, then repeat inspection intervals are reduced. Refer to Paragraph 1.E., Compliance for repaet inspection interval requirements.

**(SHEET 3 OF 3) FIGURE 47: INSPECTION FOR VERTICAL CRACKS AT CHEM-MILL LINES OF FUSELAGE SKIN**  Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 257 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT FIGURE 47: INSPECTION FOR VERTICAL CRACKS AT CHEM-MILL LINES OF FUSELAGE SKIN** 



### S-10R

S-19R S-17R STA 360 STA 540 STA 727 STA 908 STA 460

STA 312

B SEE

SEE C

SEE A SEE C SEE C SEE C



### 737-300 AIRPLANE SHOWN 737-500 SIMILAR 1 2 1 7

1 6

1 5

1 4

1 31652922

**(SHEET 1 OF 4) FIGURE 47: INSPECTION FOR VERTICAL CRACKS AT CHEM-MILL LINES OF FUSELAGE SKIN**  Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 258 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT**

INSPECTION AREA TYPICAL CRACK INSPECTION AREA TYPICAL CRACK

UP
FWD S-17R UP
FWD S-19R

S-20R LOWER SKIN PANEL LAP JOINT UPPER SKIN PANEL



### B STA 460 STA 469.90

EDGE OF SKIN 

### A STA 312

2 1

4 11652923

**(SHEET 2 OF 4) FIGURE 47: INSPECTION FOR VERTICAL CRACKS AT CHEM-MILL LINES OF FUSELAGE SKIN**  Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 259 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT**

This Figure applies to Group 18-21: 

### INSPECTION AREA TYPICAL CRACK

UP
FWD STRINGER

STRINGER

STRINGER

STRINGER

STRINGER



### C BUTT JOINT LAP JOINT UPPER AFT SKIN PANEL UPPER FORWARD SKIN PANEL



### TYPICAL CIRCUMFERENTIAL BUTT SPLICE 3 1 5 6 71652924

**(SHEET 3 OF 4) FIGURE 47: INSPECTION FOR VERTICAL CRACKS AT CHEM-MILL LINES OF FUSELAGE SKIN**  Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 260 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT** The step numbers shown below agree with the numbers shown in the circle symbols in the figure. **STEP TASK NAME IDENTIFICATION QTY MORE DATA** 1 Inspect Skin Panel - - (a) 2 Inspect Skin Panel - - (b) 3 Inspect Skin Panel - - (c) 4 Inspect Skin Panel - - (d) 5 Inspect Skin Panel - - (e) 6 Inspect Skin Panel - - (f) 7 Inspect Skin Panel - - (g) (a) Do an external detailed inspection of the fuselage skin for chem-mill cracks. (b) Do an external Low Frequency Eddy Current (LFEC) or Magneto Optical Imaging (MOI) or C-Scan inspection at STA 312 below S-19R for vertical subsurface skin cracks as given in 737 NDT, Part 6, 53-30-09 or 737 NDT, Part 6, 53-30-18 or 737 NDT, Part 6, 53-30-19 or 737 NDT, Part 6, 53-30-25. (c) Do an external LFEC or MOI or C-Scan inspection at the circumferential butt splice STA 360 between S-10L and S-10R for vertical subsurface skin cracks as given in 737 NDT, Part 6, 53-30-09 or 737 NDT, Part 6, 53-30-18 or 737 NDT, Part 6, 53-30-19 or 737 NDT, Part 6, 53-30-25. (d) Do an external LFEC or MOI or C-Scan inspection at STA 460 below S-17R for vertical subsurface skin cracks as given in 737 NDT, Part 6, 53-30-09 or 737 NDT, Part 6, 53-30-18 or 737 NDT, Part 6, 53-30-19 or 737 NDT, Part 6, 53-30-25. (e) Do an external LFEC or MOI or C-Scan inspection at the circumferential butt splice STA 540 between S-10L and S-10R on the forward side of the butt joint only for vertical subsurface skin cracks as given in 737 NDT, Part 6, 53-30-09 or 737 NDT, Part 6, 53-30-18 or 737 NDT, Part 6, 53-30-19 or 737 NDT, Part 6, 53-30-25. (f) Do an external LFEC or MOI or C-Scan inspection at the circumferential butt splice STA 727 between S-4L and S-4R on the aft side of the butt joint only for vertical subsurface skin cracks as given in 737 NDT, Part 6, 53-30-09 or 737 NDT, Part 6, 53-30-18 or 737 NDT, Part 6, 53-30-19 or 737 NDT, Part 6, 53-30-25. (g) Do an external LFEC or MOI or C-Scan inspection at the circumferential butt splice STA 908 between S-10L and S-10R for vertical subsurface skin cracks as given in 737 NDT, Part 6, 53-30-09 or 737 NDT, Part 6, 53-30-18 or 737 NDT, Part 6, 53-30-19 or 737 NDT, Part 6, 53-30-25.

**(SHEET 4 OF 4) FIGURE 48: POST REPAIR INSPECTION - SKIN CHEM-MILL CRACK REPAIR AT STRINGER 12**  Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 261 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT FIGURE 48: POST REPAIR INSPECTION - SKIN CHEM-MILL CRACK REPAIR AT STRINGER 12** 

This Figure applies to Group 3, 5, 9-10, 12, 14-15, 17-21: STA 520 TYPICAL LAP DOUBLER STA 540 STA 360

500D = 737-300 482B = 737-500 S-12 TYPICAL LAP DOUBLER

INSPECTION AREA TRIPLER DOUBLER

UP
FWD



### A SEE A

RIGHT SIDE SHOWN LEFT SIDE OPPOSITE 11654055

**(SHEET 1 OF 2) FIGURE 48: POST REPAIR INSPECTION - SKIN CHEM-MILL CRACK REPAIR AT STRINGER 12**  Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 262 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT** The step numbers shown below agree with the numbers shown in the circle symbols in the figure.

**STEP TASK NAME IDENTIFICATION QTY MORE DATA** 1 Inspect Skin - - Inspect the skin at the critical row of fasteners. (a) (a) Do LFEC inspections for cracks in the skin as given in 737 NDT, Part 6, 53-30-00 Figure 5.

**(SHEET 2 OF 2) FIGURE 49: INSPECTION FOR VERTICAL CRACKS AT CHEM-MILL LINES OF FUSELAGE SKIN**  Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 263 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT FIGURE 49: INSPECTION FOR VERTICAL CRACKS AT CHEM-MILL LINES OF FUSELAGE SKIN** 



### 727 STA

312 STA 908 STA 540 STA

460 STA

360 STA

S-19R S-17R S-10R S-2L

B SEE SEE C

SEE A SEE C SEE C SEE C



### 737-200C 1 2 1 3 1 4 1 5 1 6 1 71659372

**(SHEET 1 OF 4) FIGURE 49: INSPECTION FOR VERTICAL CRACKS AT CHEM-MILL LINES OF FUSELAGE SKIN**  Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 264 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT**

INSPECTION AREA TYPICAL CRACK INSPECTION AREA TYPICAL CRACK

UP
FWD S-17R UP
FWD S-19R

S-20R LOWER SKIN PANEL LAP JOINT UPPER SKIN PANEL



### B STA 460 STA 469.90

EDGE OF SKIN 

### A STA 312

2 1

4 11659374

**(SHEET 2 OF 4) FIGURE 49: INSPECTION FOR VERTICAL CRACKS AT CHEM-MILL LINES OF FUSELAGE SKIN**  Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 265 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT**

This Figure applies to Group 1: 

### INSPECTION AREA TYPICAL CRACK

UP
FWD STRINGER

STRINGER

STRINGER

STRINGER

STRINGER



### C BUTT JOINT LAP JOINT UPPER AFT SKIN PANEL UPPER FORWARD SKIN PANEL



### TYPICAL CIRCUMFERENTIAL BUTT SPLICE 3 1 6 5 71659375

**(SHEET 3 OF 4) FIGURE 49: INSPECTION FOR VERTICAL CRACKS AT CHEM-MILL LINES OF FUSELAGE SKIN**  Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 266 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT** The step numbers shown below agree with the numbers shown in the circle symbols in the figure. **STEP TASK NAME IDENTIFICATION QTY MORE DATA** 1 Inspect Skin Panel - - (a) 2 Inspect Skin Panel - - (b) 3 Inspect Skin Panel - - (c) 4 Inspect Skin Panel - - (d) 5 Inspect Skin Panel - - (e) 6 Inspect Skin Panel - - (f) 7 Inspect Skin Panel - - (g) (a) Do an external detailed inspection of the fuselage skin for chem-mill cracks. (b) Do an external Low Frequency Eddy Current (LFEC) or Magneto Optical Imaging (MOI) or C-Scan inspection at STA 312 below S-19R for vertical subsurface skin cracks as given in 737 NDT, Part 6, 53-30-09 or 737 NDT, Part 6, 53-30-18 or 737 NDT, Part 6, 53-30-19 or 737 NDT, Part 6, 53-30-25. (c) Do an external LFEC or MOI or C-Scan inspection at the circumferential butt splice STA 360 between S-2L and S-10R for vertical subsurface skin cracks as given in 737 NDT, Part 6, 53-30-09 or 737 NDT, Part 6, 53-30-18 or 737 NDT, Part 6, 53-30-19 or 737 NDT, Part 6, 53-30-25. (d) Do an external LFEC or MOI or C-Scan inspection at STA 460 below S-17R for vertical subsurface skin crack as given in 737 NDT, Part 6, 53-30-09 or 737 NDT, Part 6, 53-30-18 or 737 NDT, Part 6, 53-30-19 or 737 NDT, Part 6, 53-30-25. (e) Do an external LFEC or MOI or C-Scan inspection at the circumferential butt splice STA 540 between S-10L and S-10R for vertical subsurface skin cracks as given in 737 NDT, Part 6, 53-30-09 or 737 NDT, Part 6, 53-30-18 or 737 NDT, Part 6, 53-30-19 or 737 NDT, Part 6, 53-30-25. (f) Do an external LFEC or MOI or C-Scan inspection at the circumferential butt splice STA 727 between S-10L and S-10R for vertical subsurface skin cracks as given in 737 NDT, Part 6, 53-30-09 or 737 NDT, Part 6, 53-30-18 or 737 NDT, Part 6, 53-30-19 or 737 NDT, Part 6, 53-30-25. (g) Do an external LFEC or MOI or C-Scan inspection at the circumferential butt splice STA 908 between S-10L and S-10R for vertical subsurface skin cracks as given in 737 NDT, Part 6, 53-30-09 or 737 NDT, Part 6, 53-30-18 or 737 NDT, Part 6, 53-30-19 or 737 NDT, Part 6, 53-30-25.

**(SHEET 4 OF 4) APPENDIX A: COST BENEFIT ANALYSIS**  Original Issue: December 14, 2000 Revision 3: July 16, 2009 737-53A1210 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 267 of 267 

### BOEING SERVICE BULLETIN 737-53A1210 **ALERT ALERT APPENDIX A: COST BENEFIT ANALYSIS**  Boeing did a cost benefit analysis on the changes given in this service bulletin. The data that follows was used to do the analysis. Operators can use the data to do their own cost benefit analysis. The “Before the Change” data are average fleet data based on in-service experience. The “After the Change” data are estimated fleet data. Refer to Customer Cost Benefit Methodology Guide, Document D6-56722, for details on how to prepare a cost benefit analysis.
**Part Name: Part Number: Analysis Inputs Before the**  **Change After the Change**  Delays / 100 Revenue Departures 0.0 0.0 Cancellations / 100 Revenue Departures 0.0 0.0 MTBUR (flight hours) 0.0 0.0 MTBF (flight hours) 0.0 0.0 MTBO (flight hours or cycles) 0.0 0.0 Fuel Factor (weight in pounds) 0.0 0.0 Line Maintenance Hours / Removal 0.0 0.0 Line Maintenance Hours / Maintenance Action (Non Removal) 0.0 0.0

Maintenance Actions / 1,000 Flight Hours (Non Removal) 0.0 0.0

Scheduled Maintenance Hours / 1,000 Flight Hours 0.120000 0.00000 Shop Material Cost / Failure 0.0 0.0 Shop Labor Hours / Removal 0.0 0.0