### Commercial **Airplanes** 

# 757 Service Bulletin **SPECIAL ATTENTION Number: 757-53-0097**  Original Issue: November 22, 2010 ATA System: 5300 **SUBJECT:** FUSELAGE - Skin - Crown Skin Panel - Station 297 to Station 439, Chem-Milled Step Above Stringer 4 Left and Stringer 4 Right Lap Joint - Inspection Export of this technology is controlled under the United States Export Administration Regulations (EAR) (15 CFR 730-774). An export license may be required before it is used for development, production or use by foreign persons from specific countries. The controller of this data has the individual responsibility to abide by all export laws. 9E991 ECCN: 

## BOEING PROPRIETARY, CONFIDENTIAL, AND/OR TRADE SECRET Copyright © 2010 The Boeing Company Unpublished Work - All Rights Reserved Boeing claims copyright in each page of this document only to the extent that the page contains copyrightable subject matter. Boeing also claims copyright in this document as a compilation and/or collective work. This document includes proprietary information owned by The Boeing Company and/or one or more third parties. Treatment of the document and the information it contains is governed by contract with Boeing. For more information, contact The Boeing Company, P.O. Box 3707, Seattle, Washington 98124. Boeing, the Boeing signature, the Boeing symbol, 707, 717, 727, 737, 747, 757, 767, 777, 787, Dreamliner, BBJ, DC-8, DC-9, DC-10, KC-10, KDC-10, MD-10, MD-11, MD-80, MD-88, MD-90, P-8A, Poseidon and the Boeing livery are all trademarks owned by The Boeing Company; and no trademark license is granted in connection with this document unless provided in writing by Boeing.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: November 22, 2010 757-53-0097 1 of 32 3.0BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: November 22, 2010 757-53-0097 2 of 32 **BOEING SERVICE BULLETIN 757-53-0097**

BLANK PAGE**Table of Contents** Summary...................................................... 5 1. PLANNING INFORMATION ........................................ 9 A. Effectivity................................................ 9 1. Airplanes............................................. 9 2. Spares Affected . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 B. Concurrent Requirements. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 C. Reason . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 D. Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 E. Compliance. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 F. Approval . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 G. Manpower . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 H. Weight and Balance Changes. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 I. Electrical Load Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 J. References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 1. Existing Data. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 2. Data supplied with this Service Bulletin. . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 3. Installation Drawings Used in the Preparation of this Service Bulletin. . . . . . . . . . . . 16 K. Publications Affected . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 L. Interchangeability and Intermixability of Parts . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 2. MATERIAL INFORMATION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 A. Material - Price and Availability. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 B. Industry Support Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 C. Parts Necessary For Each Airplane. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 1. Kits/Parts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 2. Parts and Materials Supplied by the Operator. . . . . . . . . . . . . . . . . . . . . . . . 19 3. Parts Modified and Reidentified. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 4. Parts Removed and Not Replaced. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 D. Parts Necessary to Change Spares. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 E. Special Tooling - Price and Availability. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 F. Special Tooling Necessary to do this Service Bulletin. . . . . . . . . . . . . . . . . . . . . . . 19 3. ACCOMPLISHMENT INSTRUCTIONS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 A. GENERAL INFORMATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 B. WORK INSTRUCTIONS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 FIGURE 1: STA 297 TO STA 439 CROWN SKIN PANEL - EXTERNAL DETAILED INSPECTION - OPTION A . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 FIGURE 2: STA 297 TO STA 439 CROWN SKIN PANEL - EXTERNAL SLIDING PROBE EC INSPECTION - OPTION B. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 FIGURE 3: STA 297 TO STA 439 CROWN SKIN PANEL - EXTERNAL SPOT PROBE MFEC INSPECTION -OPTION C . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: November 22, 2010 757-53-0097 3 of 32 **BOEING SERVICE BULLETIN 757-53-0097**BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: November 22, 2010 757-53-0097 4 of 32 **BOEING SERVICE BULLETIN 757-53-0097**

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### Commercial **Airplanes** 

# 757 Service Bulletin **SPECIAL ATTENTION Summary**  **Number: 757-53-0097** Original Issue: November 22, 2010 ATA System: 5300 **SUBJECT:** FUSELAGE - Skin - Crown Skin Panel - Station 297 to Station 439, Chem-Milled Step Above Stringer 4 Left and Stringer 4 Right Lap Joint - Inspection BOEING RECOMMENDS THAT EACH OPERATOR EXAMINE THIS SERVICE BULLETIN IMMEDIATELY. **CONCURRENT REQUIREMENTS** None. **BACKGROUND** Two operators reported cracking on two airplanes in the Body Station (STA) 297 to STA 439 crown skin panel. The cracking is attributed to fatigue. Cracking may initiate at multiple locations on the interior surface, along the chem-milled step edges above the stringer 4L or 4R lap splices of the skin. Without inspection for cracks, multiple site cracks could link together and rapidly progress through the skin. A long crack could result in pressure venting and a controlled decompression of the airplane. One reported crack was 10.75-inches long midway between STA 420 and STA 439. The crack was just above the lap joint at stringer 4L common to the chem-milled step. The airplane had 24,631 flight cycles. On another airplane the operator reported an opening in the fuselage approximately 12 inches by 18 inches above and aft of the passenger entry doorway. One edge of the opening was common to the chem-milled step above stringer 4L. Additionally a 1.3" crack was found in the skin forward of the opening in the adjacent skin bay also in the chem-milled step above stringer 4L. The airplane had 22,450 flight cycles. This service bulletin gives inspection for cracks along the chem-milled pocket above the lap joints at Stringer 4 left and right side, between Body Stations 297 and 439. Accomplishment of this service bulletin will make sure that cracks are found and repaired. Boeing Service Related Problem (SRP) 757-SRP-53-0368 is related to this service bulletin. **ACTION** Get access to the exterior of the skin lap joint at stringer S-4 on the left and right sides of the airplane, between STA 297 and STA 439. Do either a sliding probe external eddy current (EC), a spot probe mid frequency eddy current (MFEC) or a detailed inspection for cracking of the STA 297 to STA 439 crown skin panel at the edge of the chem-milled pockets above stringer S-4L and S-4R lap joints as described and at the times specified in Paragraph 1.E., Compliance. If any crack is found, contact Boeing for damage removal and repair instuctions and do the repair. Repeat the sliding probe EC, spot probe MFEC or detailed inspection at the times given in Paragraph 1.E., Compliance.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: November 22, 2010 757-53-0097 5 of 32**EFFECTIVITY** 757-200, 757-200CB, 757-300 Airplanes. Refer to Paragraph 1.A.1., Airplanes, for the list of affected airplanes. **COMPLIANCE** The Federal Aviation Administration (FAA) will possibly release an Airworthiness Directive related to this service bulletin. The Airworthiness Directive will make the compliance tasks and times given in this service bulletin mandatory. Refer to Paragraph 1.E., Compliance. **INDUSTRY SUPPORT INFORMATION** At the time of release of this service bulletin, warranty remedies have not been determined. A subsequent revision or Information Notice will address the warranty remedies available, if any. **MANPOWER Elapsed Hours**  **Total Task Hours Airplanes**  1.00 1.00 Option A: External de- tailed inspection 1.00 1.00 Option B: External SlidingProbe Eddy Current Inspection 3.00 3.00 Option C: External Spot Probe Middle Frequency Eddy Current inspection
**MATERIAL INFORMATION** None.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: November 22, 2010 757-53-0097 6 of 32 **BOEING SERVICE BULLETIN 757-53-0097**BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: November 22, 2010 757-53-0097 7 of 32 **BOEING SERVICE BULLETIN 757-53-0097**BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: November 22, 2010 757-53-0097 8 of 32 **BOEING SERVICE BULLETIN 757-53-0097**

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### Commercial **Airplanes** 

# 757 Service Bulletin **SPECIAL ATTENTION Number: 757-53-0097**  Original Issue: November 22, 2010 ATA System: 5300 **SUBJECT:** FUSELAGE - Skin - Crown Skin Panel - Station 297 to Station 439, Chem-Milled Step Above Stringer 4 Left and Stringer 4 Right Lap Joint - Inspection BOEING RECOMMENDS THAT EACH OPERATOR EXAMINE THIS SERVICE BULLETIN IMMEDIATELY. **1. PLANNING INFORMATION A. Effectivity**  1. Airplanes Refer to Service Bulletin Index Document D624N001 Part 3 for Airplane Variable Number, Line Number, and Serial Number data.
**DESCRIPTION CONFIGURATION**  **GROUP** 757 Passenger Airplanes

- 1

Airplane Models: 757-200, 757-200CB, 757-300 **Group Variable Number**  1 NA001 - NA028 1 NA191 - NA199 1 NA201 - NA239 1 NA301 - NA305 1 NA341 - NA352 1 NA391 - NA399 1 NA401 - NA408 1 NA441 - NA447 1 NA501 - NA586 1 NB001 - NB004

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: November 22, 2010 757-53-0097 9 of 32**Group Variable Number**  1 NB021 - NB023 1 NB036 - NB041 1 NB051 - NB053 1 NB061 - NB073 1 NB079 1 NB131 - NB148 1 NB161 - NB162 1 NB166 - NB168 1 NB201 - NB204 1 NB221 - NB228 1 NB230 1 NB236 1 NB239 1 NB261 - NB267 1 NB291 - NB299 1 NB301 - NB302 1 NB311 - NB312 1 NB321 - NB331 1 NB421 - NB438 1 NB446 1 NB451 - NB454 1 NB501 - NB523 1 NB561 1 NB571 1 NB581 - NB583 1 NC001 - NC033 1 NC041 - NC042 1 NC051 - NC052 1 NC056 - NC062 1 NC066 - NC084 1 NC091 - NC094 1 NC151 1 NC161

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: November 22, 2010 757-53-0097 10 of 32 **BOEING SERVICE BULLETIN 757-53-0097 Group**  **Variable Number** 1 ND001 - ND007 1 ND011 - ND059 1 ND111 - ND113 1 ND161 - ND199 1 ND201 - ND203 1 ND221 - ND225 1 ND241 - ND248 1 ND301 - ND322 1 ND401 1 ND891 1 ND895 1 NE001 - NE008 1 NE011 - NE088 1 NE091 - NE094 1 NE141 - NE150 1 NE161 - NE177 1 NE201 - NE204 1 NE301 - NE302 1 NE311 - NE325 1 NJ001 - NJ004 1 NJ031 - NJ032 1 NJ551 - NJ555 1 NL001 - NL002 1 NL006 - NL017 1 NL101 - NL109 1 NL141 1 NL601 - NL616 1 NN001 - NN002 1 NN051 - NN052 1 NP901 - NP904 1 NT201 - NT202 1 NT231 - NT234 1 NT237 - NT240

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: November 22, 2010 757-53-0097 11 of 32 **BOEING SERVICE BULLETIN 757-53-0097 Group**  **Variable Number** 1 NT242 1 NT245 - NT248 1 NT281 - NT289 1 NT341 - NT347 1 NT351 - NT360 1 NT371 - NT373 1 NT375 - NT379 1 NT381 - NT386 1 NT401 - NT409 1 NT411 - NT412 1 NT426 - NT427 1 NT431 - NT432 1 NT436 - NT438 1 NT441 - NT442 1 NT446 1 NT701 - NT769 1 NT791 - NT796 1 NT861 - NT862 1 NT881 - NT885 1 NT901 - NT916 1 NT971 - NT985 1 NU031 - NU038 1 NU701 - NU705 1 NU721 - NU728 1 NU731 - NU732 2. Spares Affected None. **B. Concurrent Requirements** None.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: November 22, 2010 757-53-0097 12 of 32 **BOEING SERVICE BULLETIN 757-53-0097 C. Reason**  Two operators reported cracking on two airplanes in the Body Station (STA) 297 to STA 439 crown skin panel. The cracking is attributed to fatigue. Cracking may initiate at multiple locations on the interior surface, along the chem-milled step edges above the stringer 4L or 4R lap splices of the skin. Without inspection for cracks, multiple site cracks could link together and rapidly progress through the skin. A long crack could result in pressure venting and a controlled decompression of the airplane. One reported crack was 10.75-inches long midway between STA 420 and STA 439. The crack was just above the lap joint at stringer 4L common to the chem-milled step. The airplane had 24,631 flight cycles. On another airplane the operator reported an opening in the fuselage approximately 12 inches by 18 inches above and aft of the passenger entry doorway. One edge of the opening was common to the chem-milled step above stringer 4L. Additionally a 1.3" crack was found in the skin forward of the opening in the adjacent skin bay also in the chem-milled step above stringer 4L. The airplane had 22,450 flight cycles. This service bulletin gives inspection for cracks along the chem-milled pocket above the lap joints at Stringer 4 left and right side, between Body Stations 297 and 439. Accomplishment of this service bulletin will make sure that cracks are found and repaired. Boeing Service Related Problem (SRP) 757-SRP-53-0368 is related to this service bulletin. **D. Description** Get access to the exterior of the skin lap joint at stringer S-4 on the left and right sides of the airplane, between STA 297 and STA 439. Do either a sliding probe external eddy current (EC), a spot probe mid frequency eddy current (MFEC) or a detailed inspection for cracking of the STA 297 to STA 439 crown skin panel at the edge of the chem-milled pockets above stringer S-4L and S-4R lap joints as described and at the times specified in Paragraph 1.E., Compliance. If any crack is found, contact Boeing for damage removal and repair instuctions and do the repair. Repeat the sliding probe EC, spot probe MFEC or detailed inspection at the times given in Paragraph 1.E., Compliance. The work in this service bulletin is done in the maintenance zone(s) given below.
**Affected Maintenance Zones Zone**  **Model** 223, 224 757-200, 757-200CB, 757-300 **E. Compliance** The Federal Aviation Administration (FAA) will possibly release an Airworthiness Directive related to this service bulletin. The Airworthiness Directive will make the compliance tasks and times given in this service bulletin mandatory.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: November 22, 2010 757-53-0097 13 of 32 **BOEING SERVICE BULLETIN 757-53-0097 Table 1: STA 297 to STA 439 crown skin panel - Inspections**  **Repeat Interval (Not to Exceed)**  **Compliance Time (Whichever Occurs Later)**  **Action Condition**  30 flight cycles(a) Within 30 days after the original issue date ofthis service bulletin Before15,000 total flight cycles Option A: Do an external detailed inspection of the STA 297 to STA439 crown skin panel at stringer S4L and S-4R lap joints in accordance with Paragraph 3.B., Work Instructions, Step 2.a , (d) (e) All airplanes

300 flight cycles (b) Within 30 days after the original issue date ofthis service bulletin Before 15,000 total flight cycles Option B: Do an external sliding probe EC inspection of the STA 297 to STA 439 crown skin panel at stringer S-4L and S-4R lap joints in accordance with Paragraph 3.B., Work Instructions, Step 2.b , (d) (e) 200 flight cycles (c) Within 30 days after the original issue date ofthis service bulletin Before 15,000 total flight cycles Option C: Do an external spot probe MFEC inspection of the STA 297 to STA 439 crown skin panel at the stringer S-4L and S-4R lap joints in accordance with Paragraph 3.B., Work Instructions, Step 2.c , (d) (e) 300 flight cycles (b) Within 90 days after the original issue date ofthis service bulletin - Option B: Do an external sliding probe EC inspection of the STA 297 to STA 439 crown skin panel at stringer S-4L and S-4R lap joints in accordance with Paragraph 3.B., Work Instructions, Step 2.b , (b) (d) (e) Airplanes that accomplished Option A as the initial inspection

200 flight cycles (c) Within 90 days after the original issue date ofthis service bulletin - Option C: Do an external spot probe MFEC inspection of the STA 297 to STA 439 crown skin panel at the stringer S-4L and S-4R lap joints in accordance with Paragraph 3.B., Work Instructions, Step 2.c , (c) (d) (e)

- Before further flight Contact Boeing for damage removal and repair instructions and do the work instructed by Boeing. Any crack is found (a) Perform detailed inspections until the sliding probe EC or the spot probe MFEC methods are performed. Once the sliding probe EC or the spot probe MFEC inspections are initiated, visuals are not required. (b) A detailed inspection may be applied no more than once per repeat interval of 300 flight cycles to extend the sliding probe(EC) repeat interval up to 330 cycles, not to exceed 30 cycles from the time of the detailed inspection, to allow an airplane to get to a convenient location for inspection. (c) A detailed inspection may be applied no more than once per repeat interval of 200 flight cycles to extendthe spot probe (MFEC) repeat interval up to 230 cycles, not to exceed 30 cycles from the time of the detailed inspection, to allow an airplane to get to a convenient location for inspection.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: November 22, 2010 757-53-0097 14 of 32 **BOEING SERVICE BULLETIN 757-53-0097 Table 1: STA 297 to STA 439 crown skin panel - Inspections**  **Repeat Interval (Not to Exceed)**  **Compliance Time (Whichever Occurs Later)**  **Action Condition**  (d) Except, it is not necessary to inspect the edge of the chem-mill pocket under an existing external repair doubler provided all of the following apply: 1.The repair doubler is 0.050" or thicker 2024-T3 clad sheet; 2. The repair was approved by the FAA or by a Boeing Company Authorized Representative who was authorized by the FAA to make such findings; 3. The repair doubler extends a minimum of three rows of fasteners on each side of the chem-milled step in the circumferential direction.(e) The Boeing STC 757-200 Special Freighter converted airplanes may exclude inspections of the chemmilled pocket edge under the modification doubler between BS 416 and 439 above Stringer 4L and 4R. **F. Approval** This service bulletin was examined by the Federal Aviation Administration (FAA). The changes specified in this service bulletin comply with the applicable regulations and are FAA approved, as well as European Aviation Safety Agency (EASA)/Joint Aviation Authorities (JAA) approved for all EASA/JAA approved airplanes listed in the service bulletin effectivity. This service bulletin and its approval were based on the airplane in its original Boeing delivery configuration or as modified by other approved Boeing changes. If an airplane has a non-Boeing modification or repair that affects a component or system also affected by this service bulletin, the operator is responsible for obtaining appropriate regulatory agency approval before incorporating this service bulletin. **G. Manpower** The table below shows an estimate of the task hours necessary to do this inspection for each airplane. This estimate is for direct labor only, done by an experienced crew. Adjust the estimate with operator task hour data if necessary. The estimate does not include lost time. These are some examples of lost time: • Time to adjust to the workplace • Time to schedule the work • Time to inspect the work • Time to cure the materials • Time to make the parts • Time to find the tools. **Option A: External detailed inspection Elapsed Hours**  **Task Hours Number of Persons**  **Task** 1.00 1.00 1 FIGURE 1 1.00 1.00 TOTAL FOR EACH AIRPLANE

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: November 22, 2010 757-53-0097 15 of 32 **BOEING SERVICE BULLETIN 757-53-0097 Option B: External Sliding probe EC inspection**  **Elapsed Hours Task Hours**  **Number of Persons Task**  1.00 1.00 1 FIGURE 2 1.00 1.00 TOTAL FOR EACH AIRPLANE **Option C: External spot probe MFEC inspection Elapsed Hours**  **Task Hours Number of Persons**  **Task** 3.00 3.00 1 FIGURE 3 3.00 3.00 TOTAL FOR EACH AIRPLANE **H. Weight and Balance Changes** None. **I. Electrical Load Data** Not changed. **J. References** 1. Existing Data a. Boeing Service Related Problem (SRP) 757-SRP-53-0368 b. 737 Non-Destructive Testing (NDT) Manual Part 6, 53-30-09, Part 6, 53-30-18, Part 6, 53-30-23 c. 757 Non-Destructive Testing (NDT) Manual part 6, 53-00-10, Part 6, 53-30-14 2. Data supplied with this Service Bulletin None. 3. Installation Drawings Used in the Preparation of this Service Bulletin
**Title Drawing Number**  CROWN SKIN PANEL INSTL STA 297 TO STA 440 STR 4R TO STR 4L 141N3310
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:

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: November 22, 2010 757-53-0097 16 of 32 **BOEING SERVICE BULLETIN 757-53-0097**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 does not affect FCS, therefore DTIs are not necessary. **L. Interchangeability and Intermixability of Parts** Accomplishment of this service bulletin does not affect interchangeability or intermixability of parts.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: November 22, 2010 757-53-0097 17 of 32 **BOEING SERVICE BULLETIN 757-53-0097**BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: November 22, 2010 757-53-0097 18 of 32 **BOEING SERVICE BULLETIN 757-53-0097**

BLANK PAGE**2. MATERIAL INFORMATION A. Material - Price and Availability**  None. **B. Industry Support Information** At the time of release of this service bulletin, warranty remedies have not been determined. A subsequent revision or Information Notice will address the warranty remedies available, if any. **C. Parts Necessary For Each Airplane** 1. Kits/Parts None. 2. Parts and Materials Supplied by the Operator None. 3. Parts Modified and Reidentified None. 4. Parts Removed and Not Replaced None. **D. Parts Necessary to Change Spares** None. **E. Special Tooling - Price and Availability** None. **F. Special Tooling Necessary to do this Service Bulletin** No special tools or equipment are necessary to do the change in this service bulletin. But, maintenance and overhaul tools in the manuals given in Paragraph 1.J., References, can be necessary. Examine operator tool supply to make sure all necessary tools are available. Although no special tools are required, the sliding probe EC procedure (Option B) given in 757 NDT Part 6, 53-30-14 requires a sliding probe that may not be in the operator's inventory. Refer to 757 NDT Part 6, 53-30-14 for information about the sliding probe part number.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: November 22, 2010 757-53-0097 19 of 32 **BOEING SERVICE BULLETIN 757-53-0097**BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: November 22, 2010 757-53-0097 20 of 32 **BOEING SERVICE BULLETIN 757-53-0097**

BLANK PAGE**3. ACCOMPLISHMENT INSTRUCTIONS A. GENERAL INFORMATION**  **CAUTION:** KEEP THE WORK AREA, WIRES AND ELECTRICAL BUNDLES CLEAN OF METAL PARTICLES OR CONTAMINATION WHEN YOU USE TOOLS. UNWANTED MATERIAL, METAL PARTICLES OR CONTAMINATION CAUGHT IN WIRE BUNDLES CAN CAUSE DAMAGE TO THE BUNDLES. DAMAGED WIRE BUNDLES CAN CAUSE SPARKS OR OTHER ELECTRICAL DAMAGE. **NOTE:** 1. The instructions identified in Paragraph 3.B., Work Instructions and the Figure(s) give the recommended sequence of steps. The sequence of steps to do this service bulletin can be changed. 2. Manual titles are referred to by acronyms. Refer to Paragraph 1.J., References, for definition of the acronyms. 3. Obey all of the warnings and cautions given in the specified manual sections. 4. 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 and fasteners are in Structural Repair Manual (SRM) Chapter 51 – Torque limits to tighten nuts and bolts are in SRM Chapter 51 5. Use the approved fastener and process material substitutions in accordance with SRM Chapter 51. Alternate fasteners are listed in SRM Chapter 51 and Boeing Drawing 65-88700. 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. These work instructions refer to procedures included in other Boeing documents. When the words "refer to" are used and the operator has an accepted alternative procedure, the accepted alternative procedure can be used. When the words "in accordance with" are included in the instruction, the procedure in the Boeing document must be used.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: November 22, 2010 757-53-0097 21 of 32 **BOEING SERVICE BULLETIN 757-53-0097**8. Boeing Service Letter 757-SL-51-022, Damage Reporting and Repair Plan/Design Guidelines, is an acceptable procedure to request information from Boeing for additional structural repair instructions. The Service Letter describes what information must be provided to Boeing before a structural repair can be provided. 9. The instructions in Paragraph 3.B., Work Instructions and the figures can include operation of tools or test equipment. Boeing Engineering Tool Drawings, the Illustrated Tool and Equipment Manual, and the Special Tool and Ground Handling Drawing Index contain data on versions of the tools or test equipment that you can use. It is permitted to use replaced tools. It is not permitted to use superseded tools. 10. If it is necessary to remove more parts for access, you can remove those parts. If you can get access without removing identified parts, it is not necessary to remove all of the identified parts. Jacking and shoring limitations must be observed. **B. WORK INSTRUCTIONS** 1. Get access to the exterior of the skin above the lap joint at stringer S-4 on the left side from Body Station (STA) 297 to STA 324 and from STA 377.7 to STA 439, and above the lap joint at S-4 on the right side of the airplane between (STA) 297 and STA 439. 2. Do one of the following inspections at the times given in Paragraph 1.E., Compliance except as given in the following notes: **NOTE:** The Boeing STC 757-200 Special Freighter converted airplanes may exclude inspections of the chem-milled pocket edge under the modification doubler between BS 416 and 439 above Stringer 4L and 4R. **NOTE:** It is not necessary to inspect the chem-mill pocket edge under an existing external repair or modification doubler provided all of the following apply: 1. The repair doubler is 0.050" or thicker 2024-T3 clad sheet. 2. The repair was approved by the FAA or by a Boeing Company Authorized Representative who was authorized by the FAA to make such findings. 3. The repair extends a minimum of three rows of fasteners on each side of the chem-milled step in the circumferential direction. a. OPTION A: Do an external detailed inspection for cracking of the crown skin panel from STA 297 to STA 324 and from STA 377.7 to STA 439 at the edge of the chem-milled pockets above S-4L, and from STA 297 to STA 439 at the edge of the chem-milled pockets above S-4R, at the locations shown in accordance with FIGURE 1.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: November 22, 2010 757-53-0097 22 of 32 **BOEING SERVICE BULLETIN 757-53-0097**(1) If any crack is found, contact Boeing for damage removal and repair instructions and do the work instructed by Boeing. (2) Repeat inspections at the times given in Paragraph 1.E., Compliance until EC or MFEC is done at the time specified in I E, Compliance. b. OPTION B: Do an external sliding probe Eddy Current (EC) inspection for cracking of the crown skin panel from STA 297 to STA 324 and from STA 377.7 to STA 439 at the edge of the chem-milled pockets above S-4L, and from STA 297 to STA 439 at the edge of the chem-milled pockets above S-4R, at the locations shown in accordance with FIGURE 2. (1) If any crack is found, contact Boeing for damage removal and repair instructions and do the work instructed by Boeing. (2) Repeat inspections at the times given in Paragraph 1.E., Compliance. c. OPTION C: Do an external spot probe Middle Frequency Eddy Current (MFEC) inspection for cracking of the crown skin panel from STA 297 to STA 324 and from STA 377.7 to STA 439 at the edge of the chem-milled pockets above S-4L, and from STA 297 to STA 439 at the edge of the chem-milled pockets above S-4R, at the locations shown in accordance with FIGURE 3 (1) If any crack is found, contact Boeing for damage removal and repair instructions and do the work instructed by Boeing. (2) Repeat inspections at the times given in Paragraph 1.E., Compliance. 3. Put the airplane back to a serviceable condition.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: November 22, 2010 757-53-0097 23 of 32 **BOEING SERVICE BULLETIN 757-53-0097 FIGURE 1: STA 297 TO STA 439 CROWN SKIN PANEL - EXTERNAL DETAILED INSPECTION - OPTION**  **A (SHEET 1 OF 3)** 

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: November 22, 2010 757-53-0097 24 of 32 **BOEING SERVICE BULLETIN 757-53-0097 FIGURE 1: STA 297 TO STA 439 CROWN SKIN PANEL - EXTERNAL DETAILED INSPECTION - OPTION**  **A (SHEET 2 OF 3)** 

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: November 22, 2010 757-53-0097 25 of 32 **BOEING SERVICE BULLETIN 757-53-0097**The step numbers shown below agree with the numbers shown in the circle symbols in the figure.
**MORE DATA QTY**  **IDENTIFICATION NAME**  **TASK STEP**  (a)

- - CROWN SKIN PANEL Inspect 1 (a) Do an external detailed inspection for cracks in the crown skin panel along the edge of the chem-milled pocket above the lap joint.

**FIGURE 1: STA 297 TO STA 439 CROWN SKIN PANEL - EXTERNAL DETAILED INSPECTION - OPTION A**  **(SHEET 3 OF 3)**

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: November 22, 2010 757-53-0097 26 of 32 **BOEING SERVICE BULLETIN 757-53-0097 FIGURE 2: STA 297 TO STA 439 CROWN SKIN PANEL - EXTERNAL SLIDING PROBE EC INSPECTION -**  **OPTION B (SHEET 1 OF 3)** 

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: November 22, 2010 757-53-0097 27 of 32 **BOEING SERVICE BULLETIN 757-53-0097 FIGURE 2: STA 297 TO STA 439 CROWN SKIN PANEL - EXTERNAL SLIDING PROBE EC INSPECTION -**  **OPTION B (SHEET 2 OF 3)** 

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: November 22, 2010 757-53-0097 28 of 32 **BOEING SERVICE BULLETIN 757-53-0097**The step numbers shown below agree with the numbers shown in the circle symbols in the figure.
**MORE DATA QTY**  **IDENTIFICATION NAME**  **TASK STEP**  (a)

- - CROWN SKIN PANEL Inspect 1(a) Do an external sliding probe EC inspection for cracks in the crown skin panel along the edge of the chemmilled pocket above the lap joint in accordance with 757 NDT Part 6, 53-30-14.

**FIGURE 2: STA 297 TO STA 439 CROWN SKIN PANEL - EXTERNAL SLIDING PROBE EC INSPECTION - OPTION B**  **(SHEET 3 OF 3)**

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: November 22, 2010 757-53-0097 29 of 32 **BOEING SERVICE BULLETIN 757-53-0097 FIGURE 3: STA 297 TO STA 439 CROWN SKIN PANEL - EXTERNAL SPOT PROBE MFEC INSPECTION**  **-OPTION C (SHEET 1 OF 3)** 

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: November 22, 2010 757-53-0097 30 of 32 **BOEING SERVICE BULLETIN 757-53-0097 FIGURE 3: STA 297 TO STA 439 CROWN SKIN PANEL - EXTERNAL SPOT PROBE MFEC INSPECTION**  **-OPTION C (SHEET 2 OF 3)** 

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: November 22, 2010 757-53-0097 31 of 32 **BOEING SERVICE BULLETIN 757-53-0097**The step numbers shown below agree with the numbers shown in the circle symbols in the figure.
**MORE DATA QTY**  **IDENTIFICATION NAME**  **TASK STEP**  (a) (b)

- - CROWN SKIN PANEL Inspect 1 (a) Do an external spot probe MFEC inspection for cracks in the crown skin panel along the edge of the chem-milled pocket above the lap joint in accordance with 757 NDT Part 6, 53-00-10. (b) 737 NDT Part 6, 53-30-23 and 737 NDT Part 6, 53-30-09 and 737 NDT Part 6, 53-30-18 are equivalent to 757 NDT Part 6, 53-00-10 for instrument calibration. Follow this service bulletin for the required inspection areas.

**FIGURE 3: STA 297 TO STA 439 CROWN SKIN PANEL - EXTERNAL SPOT PROBE MFEC INSPECTION -OPTION C**  **(SHEET 3 OF 3)**

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: November 22, 2010 757-53-0097 32 of 32 **BOEING SERVICE BULLETIN 757-53-0097**