### Commercial **Airplanes** 

# 747 Service Bulletin **ALERT Number: 747-54A2237**  Original Issue: March 14, 2013 ATA System: 5410 **SUBJECT:** NACELLES/PYLONS - Nacelle Strut - Outboard Struts GE CF6-45/50 and JT9D-70 Series Engines - Lower Spar Inspection and Modification Export of this technology is controlled under the United States Export Administration Regulations (EAR) (15 CFR 300-774). An export license may be required before it is used for development, production or use by foreign persons from specific countries. The controller of this data has the individual responsibility to abide by all export laws. 9E991 ECCN: 

## BOEING PROPRIETARY, CONFIDENTIAL AND/OR TRADE SECRET Copyright © 2013 Boeing. Unpublished Work. All Rights Reserved. Treatment of this document and its content is governed by contract with Boeing. Rights to use this document are licensed on a per aircraft basis and such rights may not be transferable. For more information, contact The Boeing Company. Boeing, the Boeing signature, the Boeing symbol, 707, 717, 727, 737, 747, 757, 767, 777, 787, Dreamliner, BBJ, DC-8, DC-9, DC-10, KC-10, KC-46, KDC-10, MD-10, MD-11, MD-80, MD-88, MD-90, P-8, Poseidon and Boeing liveries are all trademarks owned by The Boeing Company; and no trademark license is granted in connection with this document unless provided in writing by Boeing.

Original Issue: March 14, 2013 747-54A2237 1 of 59 4.0Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: March 14, 2013 747-54A2237 2 of 59 **BOEING SERVICE BULLETIN 747-54A2237 ALERT**  **ALERT**

BLANK PAGE**Table of Contents** Summary...................................................... 5 1. PLANNING INFORMATION ........................................ 9 A. Effectivity................................................ 9 1. Airplanes............................................. 9 2. Spares Affected . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 B. Concurrent Requirements. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 C. Reason . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 D. Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 E. Compliance. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 F. Approval . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 G. Manpower . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 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:. . . . . . . . . . . 17 K. Publications Affected . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 L. Interchangeability and Intermixability of Parts. . . . . . . . . . . . . . . . . . . . . . . . . . . 17 M. Software Accomplishment Summary. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 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. . . . . . . . . . . . . . . . . . . . . . . . 20 3. Parts Modified and Reidentified. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 4. Parts Removed and Not Replaced. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 D. Parts Necessary to Change Spares. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 E. Special Tooling - Price and Availability. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 F. Special Tooling Necessary to do this Service Bulletin. . . . . . . . . . . . . . . . . . . . . . . 21 3. ACCOMPLISHMENT INSTRUCTIONS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 A. GENERAL INFORMATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 B. WORK INSTRUCTIONS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 FIGURE 1: STRUT NO. 1 - LOWER SPAR - LOWER SURFACE DET AND HFEC INSPECTION . . . 28 FIGURE 2: STRUT NO. 1 - LOWER SPAR - INTERIOR SURFACES DET INSPECTION. . . . . . . 31 FIGURE 3: STRUT NO. 1 - LOWER SPAR - HFEC INSPECTION AND FASTENER REPLACEMENT . 34 FIGURE 4: STRUT NO. 4 - LOWER SPAR - LOWER SURFACE DET AND HFEC INSPECTION . . . 38 FIGURE 5: STRUT NO. 4 - LOWER SPAR - INTERIOR SURFACES DET INSPECTION. . . . . . . 41 FIGURE 6: STRUT NO. 4 - LOWER SPAR - HFEC INSPECTION AND FASTENER REPLACEMENT . 44 FIGURE 7: STRUT NO. 1 - LOWER SPAR - LOWER SURFACE DET INSPECTION. . . . . . . . . 48 FIGURE 8: STRUT NO. 1 - INTERIOR SURFACES DET INSPECTION. . . . . . . . . . . . . . . . . 51 FIGURE 9: STRUT NO. 4 - LOWER SPAR - LOWER SURFACE DET INSPECTION. . . . . . . . . 54 FIGURE 10: STRUT NO. 4 - LOWER SPAR WEB - INTERIOR SURFACES DET INSPECTION. . . . 57

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: March 14, 2013 747-54A2237 3 of 59 **BOEING SERVICE BULLETIN 747-54A2237 ALERT**  **ALERT**Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: March 14, 2013 747-54A2237 4 of 59 **BOEING SERVICE BULLETIN 747-54A2237 ALERT**  **ALERT**

BLANK PAGE

### Commercial **Airplanes** 

# 747 Service Bulletin **ALERT Summary**  **Number: 747-54A2237** Original Issue: March 14, 2013 ATA System: 5410 **SUBJECT:** NACELLES/PYLONS - Nacelle Strut - Outboard Struts GE CF6-45/50 and JT9D-70 Series Engines - Lower Spar Inspection and Modification 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 this inspection or change will reduce the possibility of having severed lower spar chords. Lower spar chords that are severed can result in reduced structural integrity of the diagonal brace load path. Loss of the diagonal brace load path could compromise the strut to wing attachment which can result in the separation of a strut and engine from the airplane during flight. One operator reported finding both lower chords and the web on outboard strut no. 1 cracked at Nac. Sta. 300 on a strut with approximately 41,300 flight-cycles and 63,300 flight-hours. It is believed that the cracking was due to fatigue from normal operating loads. The chords are the main load path for the diagonal brace attach fitting. If the chord severs completely, it would reduce the structural integrity of the diagonal brace load path. Loss of the diagonal brace load path could compromise the strut to wing attachment. Detailed (DET) and High Frequency Eddy Current (HFEC) inspection of the web and chords will detect a crack prior to the load path being compromised. Accomplishment of the modification will remove fatigue damaged material and zero-time the holes in the chords. Zero-timing the holes will terminate the HFEC inspections of the chords. Boeing Service Related Problem (SRP) 747-SRP-54-0143 is related to this service bulletin. Boeing Fleet Team Digest (FTD) 747 FTD 54-12001 is related to this service bulletin. This table is provided to operators for planning purposes only. Refer to the applicable sections for more information.
**Reference Affected**  **Planning Data** Paragraph 1.A.2., Spares Affected No Spares Affected

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: March 14, 2013 747-54A2237 5 of 59**Reference Affected**  **Planning Data** Paragraph 1.E., Compliance and Paragraph 1.F., Approval Yes AD Related Paragraph 1.H., Weight and Balance Changes No Weight and Balance Change Paragraph 1.I., Electrical Load Data No Electrical Load Changed Paragraph 1.K., Publications Affected Yes Publications Affected Paragraph 1.K., Publications Affected No Airplane Flight Operations Affected (Flight CrewOperations Manual and/or FAA Approved Airplane Flight Manual) Paragraph 2.C.1., Kits/Parts Yes Kits/Parts Required Paragraph 2.C.2., Parts and Materials Supplied by the Operator Yes Operator Supplied Parts/Material Paragraph 2.F., Special Tooling Necessary to do this Service Bulletin No Special Tooling Required

**ACTION** PART 1: LOWER SPAR DET AND HFEC INSPECTION Open access panels to gain access to the interior of the strut. Open the side cowls to gain access to the bottom of the strut. Do a Detailed (DET) and High Frequency Eddy Current (HFEC) inspection of the lower chords for cracks and a DET of the web for cracks from the bottom of the strut. Close the side cowls. Do a DET inspection of the lower chords and the web for cracks from inside the strut. Close access panels. PART 2: LOWER SPAR CHORD MODIFICATION Open access panels to gain access to the interior of the strut. Remove left side cowl or open the side cowls to gain access to the bottom of the strut. Remove the critical fasteners. Do an open-hole HFEC inspection of the holes for cracks. Oversize holes (insurance cut) to remove fatigue damaged material. Install oversize fasteners. Install the left side cowl or close the side cowls. Close access panels. PART 3: LOWER SPAR REPAIR Repair any part with crack in accordance with the Structural Repair Manual or contact The Boeing Company for repair instructions for the lower spar chords and do the repair. PART 4: LOWER SPAR DET INSPECTION Open access panels to gain access to the interior of the strut. Open the side cowls to gain access to the bottom of the strut. Do a Detailed (DET) inspection of the web and chords for cracks from the bottom of the strut. Close the side cowls. Do a DET inspection of the web and chords for cracks from inside the strut. Close access panels. **EFFECTIVITY** 747-200B, -200C, -200F, -300 and SR Airplanes powered by GE CF6-45/50 Series engines and PW JT9D-70 engines. Refer to Paragraph 1.A.1., Airplanes, for the list of affected airplanes

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: March 14, 2013 747-54A2237 6 of 59 **BOEING SERVICE BULLETIN 747-54A2237 ALERT**  **ALERT COMPLIANCE**  The Federal Aviation Administration (FAA) will possibly release an Airworthiness Directive related to this service bulletin. The Airworthiness Directive will make the compliance tasks and times given in this service bulletin mandatory. Refer to Paragraph 1.E., Compliance. **INDUSTRY SUPPORT INFORMATION** Boeing warranty remedies are not available for the configuration changes, inspection, and/or repair procedures given in this service bulletin. **MANPOWER Elapsed Time**  **Task Hours** 15.25 26.50 PART 1: LOWER SPAR DET AND HFEC INSPECTION 10.50 10.50 PART 2: LOWER SPAR CHORD MODIFICATION (a) (a) PART 3: LOWER SPAR REPAIR 15.25 26.50 PART 4: LOWER SPAR DET INSPECTION (a) No estimate given. Task Hours and Elapsed Hours depend on the scope of the repair which is variable.
**MATERIAL INFORMATION** Boeing Supplied Kits/Parts. Refer to Paragraph 2.A., Material - Price and Availability.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: March 14, 2013 747-54A2237 7 of 59 **BOEING SERVICE BULLETIN 747-54A2237 ALERT**  **ALERT**Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: March 14, 2013 747-54A2237 8 of 59 **BOEING SERVICE BULLETIN 747-54A2237 ALERT**  **ALERT**

### Commercial **Airplanes** 

# 747 Service Bulletin **ALERT Number: 747-54A2237**  Original Issue: March 14, 2013 ATA System: 5410 **SUBJECT:** NACELLES/PYLONS - Nacelle Strut - Outboard Struts GE CF6-45/50 and JT9D-70 Series Engines - Lower Spar Inspection and Modification 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 D6-30300 Part 3 for Airplane Variable Number, Line Number, and Serial Number data. This service bulletin is for the airplane(s) shown below.
**DESCRIPTION CONFIGURATION**  **GROUP** 747-200B, -200C, -200F, -300, and SR Airplanes line numbers 202 through 886 powered by GE CF6-45/50 Series or JT9D-70 Series engines. - 1

Airplane Models: 747-200B, 747-200C, 747-200F, 747-300, 747SR **Group Variable Number**  1 RB013 - RB016 1 RB681 - RB697 1 RD044 1 RD171 - RD172 1 RD181 - RD183

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: March 14, 2013 747-54A2237 9 of 59**Group Variable Number**  1 RD231 - RD235 1 RD271 - RD272 1 RD291 - RD292 1 RD361 - RD366 1 RD381 - RD383 1 RD411 - RD414 1 RD451 - RD456 1 RD461 1 RD561 1 RD581 - RD583 1 RD591 - RD592 1 RD601 - RD607 1 RD641 - RD649 1 RD651 - RD659 1 RD661 1 RD691 - RD692 1 RD701 - RD702 1 RD721 - RD722 1 RD751 - RD755 1 RD771 - RD775 1 RD791 - RD792 1 RJ321 - RJ322 1 RJ331 - RJ333 1 RR202 - RR206 1 RR221 - RR224 1 RR301 - RR310 1 RR331 - RR332 1 RR421 1 RR551 - RR556 1 RR561 1 RS201 1 RS711 - RS713 1 RS721 - RS722

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: March 14, 2013 747-54A2237 10 of 59 **BOEING SERVICE BULLETIN 747-54A2237 ALERT**  **ALERT Group**  **Variable Number** 1 RS751 - RS752 1 RS761 - RS762 2. Spares Affected None. **B. Concurrent Requirements** None. **C. Reason** Accomplishment of this inspection or change will reduce the possibility of having severed lower spar chords. Lower spar chords that are severed can result in reduced structural integrity of the diagonal brace load path. Loss of the diagonal brace load path could compromise the strut to wing attachment which can result in the separation of a strut and engine from the airplane during flight. One operator reported finding both lower chords and the web on outboard strut no. 1 cracked at Nac. Sta. 300 on a strut with approximately 41,300 flight-cycles and 63,300 flight-hours. It is believed that the cracking was due to fatigue from normal operating loads. The chords are the main load path for the diagonal brace attach fitting. If the chord severs completely, it would reduce the structural integrity of the diagonal brace load path. Loss of the diagonal brace load path could compromise the strut to wing attachment. Detailed (DET) and High Frequency Eddy Current (HFEC) inspection of the web and chords will detect a crack prior to the load path being compromised. Accomplishment of the modification will remove fatigue damaged material and zero-time the holes in the chords. Zero-timing the holes will terminate the HFEC inspections of the chords. Boeing Service Related Problem (SRP) 747-SRP-54-0143 is related to this service bulletin. Boeing Fleet Team Digest (FTD) 747 FTD 54-12001 is related to this service bulletin. **D. Description** PART 1: LOWER SPAR DET AND HFEC INSPECTION Open access panels to gain access to the interior of the strut. Open the side cowls to gain access to the bottom of the strut. Do a Detailed (DET) and High Frequency Eddy Current (HFEC) inspection of the lower chords for cracks and a DET of the web for cracks from the bottom of the strut. Close the side cowls. Do a DET inspection of the lower chords and the web for cracks from inside the strut. Close access panels. PART 2: LOWER SPAR CHORD MODIFICATION Open access panels to gain access to the interior of the strut. Remove left side cowl or open the side cowls to gain access to the bottom of the strut. Remove the critical fasteners. Do an open-hole HFEC inspection of the holes for cracks. Oversize holes (insurance cut) to remove fatigue damaged material. Install oversize fasteners. Install the left side cowl or close the side cowls. Close access panels.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: March 14, 2013 747-54A2237 11 of 59 **BOEING SERVICE BULLETIN 747-54A2237 ALERT**  **ALERT**PART 3: LOWER SPAR REPAIR Repair any part with crack in accordance with the Structural Repair Manual or contact The Boeing Company for repair instructions for the lower spar chords and do the repair. PART 4: LOWER SPAR DET INSPECTION Open access panels to gain access to the interior of the strut. Open the side cowls to gain access to the bottom of the strut. Do a Detailed (DET) inspection of the web and chords for cracks from the bottom of the strut. Close the side cowls. Do a DET inspection of the web and chords for cracks from inside the strut. Close access panels. The work in this service bulletin is done in the maintenance zone(s) given below.
**Affected Maintenance Zones Zone**  **Model** 453, 483 747-200B, 747-200C, 747-200F, 747-300, 747SR **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. When more than one OPTION is given for a CONDITION, do only one of the OPTION numbers. When more than one ACTION is given for a CONDITION number or an OPTION number, do all of the ACTION numbers for that CONDITION number or OPTION number. The Conditions, Actions and Compliance times shown apply to each strut independently. Do the required actions in accordance with Paragraph 3. Accomplishment Instructions. **Table 1: Lower Spar Chord and Web, Detailed (DET) and High Frequency Eddy Current (HFEC) Inspection before the accomplishment of PART 2: LOWER SPAR CHORD MODIFICATION**  **Repeat Inter val (Not to Ex**  **ceed) Compliance Time (Whichever Occurs**  **Later) Action**  **Condition**

- Within 120 days af-ter the original issue date of this service bulletin. Before 20,000 total flight-cycles on the strut. Do PART 1: LOWER SPAR DET AND HFEC INSPECTION for cracks. All Airplanes

- Within 36 Monthsafter the original issue date of this service bulletin. Before 20,000 total flight-cycles on the strut. Do PART 1: LOWER SPAR DET AND HFEC INSPECTION for cracks and PART 2: LOWER SPAR CHORD MODIFICATION. (a) All Airplanes

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: March 14, 2013 747-54A2237 12 of 59 **BOEING SERVICE BULLETIN 747-54A2237 ALERT**  **ALERT Table 1: Lower Spar Chord and Web, Detailed (DET) and High Frequency Eddy Current (HFEC) Inspection**  **before the accomplishment of PART 2: LOWER SPAR CHORD MODIFICATION Repeat Inter** **val (Not to Ex ceed)**  **Compliance Time (Whichever Occurs Later)**  **Action Condition** 

600 flight-cycles. - - OPTION 1: Repeat PART 1: LOW-ER SPAR DET AND HFEC INSPECTION for cracks. CONDITION 1: NO CRACK FOUND

- - Within 600 flight- cycles from the last PART 1: LOWER SPAR DET ANDHFEC INSPECTION. OPTION 2: Do PART 1: LOWERSPAR DET AND HFEC INSPECTION for cracks and PART 2: LOWER SPAR CHORD MODIFICATION. (a)

- - Before further flight. CONDITION 2 (ACTION 1): Repair any part with crack in accordancewith PART 3: LOWER SPAR REPAIR. CONDITION 2: ANY CRACK FOUND

- - Before further flight. CONDITION 2 (ACTION 2): Do PART 2: LOWER SPAR CHORD MODIFICATION. (a) (a) Accomplishing PART 1: LOWER SPAR DET AND HFEC INSPECTION at the same time as PART 2:LOWER SPAR CHORD MODIFICATION terminates the PART 1: LOWER SPAR DET AND HFEC INSPECTION. See Table 2: Lower Spar Web, Detailed (DET) Inspection after accomplishment of PART 2: LOWER SPAR CHORD MODIFICATION for inspections required after the accomplishment of PART 2: LOWER SPAR CHORD MODIFICATION. **Table 2: Lower Spar Web, Detailed (DET) Inspection after the accomplishment of PART 2: LOWER SPAR CHORD MODIFICATION**  **Repeat Inter val (Not to Ex**  **ceed) Compliance Time (Whichever Occurs**  **Later) Action**  **Condition**

- - Within 18 monthsafter accomplishment of PART 2: LOWER SPARCHORD MODIFICATION. Do PART 4: LOWER SPAR DET INSPECTION for cracks. All Airplanes

18 months.

- - Repeat PART 4: LOWER SPAR DET INSPECTION for cracks. CONDITION 3: NO CRACK FOUND

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: March 14, 2013 747-54A2237 13 of 59 **BOEING SERVICE BULLETIN 747-54A2237 ALERT**  **ALERT Table 2: Lower Spar Web, Detailed (DET) Inspection after the accomplishment of PART 2: LOWER SPAR**  **CHORD MODIFICATION Repeat Inter** **val (Not to Ex ceed)**  **Compliance Time (Whichever Occurs Later)**  **Action Condition** 

- - Before further flight. CONDITION 4 (ACTION 1): Repair in accordance with PART 3: LOWER SPAR REPAIR. CONDITION 4: ANY CRACK FOUND 18 months.

- Within 18 months after PART 3:LOWER SPAR REPAIR was accomplished. CONDITION 4 (ACTION 2): DoPART 4: LOWER SPAR DET INSPECTION for cracks.

**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 and change 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. **PART 1: LOWER SPAR DET AND HFEC INSPECTION Elapsed Hours**  **Task Hours Number of Per-**  **sons Task** 
1.00 1.00 1 Open Access Inspect Exterior (from bottom of strut) 2.00 4.00 2 ...Strut No. 1 - FIGURE 1

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: March 14, 2013 747-54A2237 14 of 59 **BOEING SERVICE BULLETIN 747-54A2237 ALERT**  **ALERT PART 1: LOWER SPAR DET AND HFEC INSPECTION**  **Elapsed Hours Task Hours**  **Number of Per- sons**  **Task**
2.00 4.00 2 ...Strut No. 4 - FIGURE 4 Inspect Interior 3.63 7.25 2 ...Strut No. 1 - FIGURE 2 3.63 7.25 2 ...Strut No. 4 - FIGURE 5 1.00 1.00 1 Close Access 7.63 13.25 TOTAL FOR EACH STRUT 15.25 26.50 TOTAL FOR EACH AIRPLANE
**PART 2: LOWER SPAR CHORD MODIFICATION Elapsed Hours**  **Task Hours Number of Per-**  **sons Task** 
1.00 1.00 1 Open Access Remove fastener, inspect hole, and install fastener. 3.25 3.25 1 ...Strut No. 1 - FIGURE 3 3.25 3.25 1 ...Strut No. 4 - FIGURE 6 1.00 1.00 1 Close Access 5.25 5.25 TOTAL FOR EACH STRUT 10.50 10.50 TOTAL FOR EACH AIRPLANE
**PART 3: LOWER SPAR REPAIR Elapsed Hours**  **Task Hours Number of Per-**  **sons Task**  Repair Chords (a) (a) (a) ...Strut No. 1 (a) (a) (a) ...Strut No. 4 (a) (a) TOTAL FOR EACH STRUT (a) (a) TOTAL FOR EACH AIRPLANE (a) No estimate given. Number of Persons, Task Hours, and Elapsed Hours depend on the scope of the repair which is variable.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: March 14, 2013 747-54A2237 15 of 59 **BOEING SERVICE BULLETIN 747-54A2237 ALERT**  **ALERT PART 4: LOWER SPAR DET INSPECTION**  **Elapsed Hours Task Hours**  **Number of Per- sons**  **Task**
1.00 1.00 1 Open Access Inspect Exterior (from bottom of strut) 2.00 4.00 2 ...Strut No. 1 - FIGURE 7 2.00 4.00 2 ...Strut No. 4 - FIGURE 9 Inspect Interior 3.63 7.25 2 ...Strut No. 1 - FIGURE 8 3.63 7.25 2 ...Strut No. 4 - FIGURE 10 1.00 1.00 1 Close Access 7.63 13.25 TOTAL FOR EACH STRUT 15.25 26.50 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) 747-SRP-54-0143 b. Service Bulletin Index D6-30300 c. Standard Wiring Practices Manual (SWPM) 20-10-11, 20-10-12, 20-10-19 d. 747 Fleet Team Digest (FTD) 54-12001 e. 747 Non-Destructive Testing (NDT) Manual Part 6, 51-00-00 f. 747-100/200/300 Aircraft Maintenance Manual (AMM) 12-09-09, 71-11-04 g. 747-100/200/300 Structural Repair Manual (SRM) 54-11-03, 54-12-03
2. Data Supplied with this Service Bulletin: None.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: March 14, 2013 747-54A2237 16 of 59 **BOEING SERVICE BULLETIN 747-54A2237 ALERT**  **ALERT**3. Installation Drawings Used in the Preparation of this Service Bulletin:
**Title Drawing Number**  Spar Installation - LWR Aft (WL 1310), Outbd Nacelle 65B94115 The table above lists applicable drawings used to prepare this service bulletin. The drawings are not necessary to make the specified changes, and are not supplied with this service bulletin. The drawings may not be applicable to all airplane configurations or operators. **K. Publications Affected** 1. Publications: **Chapter-Section Publication**  54-41 747 Illustrated Parts Catalog 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. DTI requirements for the structure affected are contained in Paragraph 1.E., Compliance of this service bulletin. **L. Interchangeability and Intermixability of Parts** Accomplishment of this service bulletin does not affect interchangeability or intermixability of parts. **M. Software Accomplishment Summary** Not affected.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: March 14, 2013 747-54A2237 17 of 59 **BOEING SERVICE BULLETIN 747-54A2237 ALERT**  **ALERT**Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: March 14, 2013 747-54A2237 18 of 59 **BOEING SERVICE BULLETIN 747-54A2237 ALERT**  **ALERT**

BLANK PAGE**2. MATERIAL INFORMATION A. Material - Price and Availability**  Boeing can supply the kit shown in Paragraph 2.C., Parts Necessary for Each Airplane. Operators are encouraged to share schedule requirements with Boeing for incorporation of the service bulletin. The kits are subject to the terms and conditions of the Boeing standard purchase order acknowledgment. Prices are in United States Dollars. Terms: Net 30 days. Reference this service bulletin and submit your purchase order by one of these methods: 1. Order on-line via ATA Spec 2000 or The Boeing PART Page 2. Fax to (206) 662-7145 **REFER TO THE BOEING PART PAGE ON MYBOEINGFLEET.COM OR CONTACT FIRST RESPONDER AT FR@BOEING.COM FOR THE LATEST REORDER LEAD TIME (ROLT) AND PRICE INFORMATION** 
**Unit Price as of the original issue** **date of this Ser vice Bulletin (US**  **Dollars) ROLT as of the**  **original issue date of this Ser** **vice Bulletin (Cal endar Days)**  **QTY Date**  **Name Kit / Part**  **Number**

$ 95.00 139 1 January 8, 2013 Top Kit - Outboard Strut Lower Spar - GE CF6-45/50 / JT9D-70 - Change 015U1940-1 1 March 12, 2013 $6,540.00 (b) 3 February 5, 2013 Chord - Outboard Strut 65B94115-3 (a) $6,540.00 (b) 3 February 5, 2013 Chord - Outboard Strut 65B94115-4 (a) (a) Required only if cracks are found and chord needs to be replaced. (b) REFER TO THE BOEING PART PAGE ON MYBOEINGFLEET.COM OR CONTACT FIRST RESPONDER AT FR@BOEING.COM FOR THE LATEST REORDER LEAD TIME (ROLT) AND PRICE INFORMATION **B. Industry Support Information** Boeing warranty remedies are not available for the configuration changes, inspection, and/or repair procedures given in this service bulletin. **C. Parts Necessary for Each Airplane** 1. Kits/Parts To get the kits/parts shown below, refer to Paragraph 2.A., Material - Price and Availability. **NOTE:** One top kit and the items shown in Paragraph 2.C.2., Parts and Materials Supplied by the Operator, are necessary for each airplane.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: March 14, 2013 747-54A2237 19 of 59 **BOEING SERVICE BULLETIN 747-54A2237 ALERT**  **ALERT ALL** 
**Kit 015U1940 Notes**  **Existing Part Number**  **Name Qty**  **New Part Number -1**  Top Kit - Outboard Strut Lower Spar - GE CF6-45/50 / JT9D-70 - Change - 015U1940-1

(a) BOLT, PROTRUD- ING HD 12 BACB30MB8A4U (a) COLLAR 12 BACC30BH8S (a) If grip length shown is not available at Boeing, fasteners supplied in kits may be one grip length longer than indicated. Also, if any fasteners part numbers listed are not available or have been superseded, substitute fasteners may be supplied in kits. 2. Parts and Materials Supplied by the Operator The following parts or materials are necessary to do the change in this service bulletin. Parts and materials in the manuals given in Paragraph 1.J., References, can also be necessary. Examine operator part and material supply to make sure all necessary parts and materials are available.
**Notes Name**  **Qty Part Number/ Specification**  (a) Sealant 8 Oz BMS 5-63 (b) Sheet (2) 14.6 X 36.0 0.040 15-5 PH CRES SHEET, HEAT TREAT 180 - 200 KSI (Optional : 0.040 SHEET, BMS 7-240, Type 1 SOLUTION TREATED 15-5 PH CRES, HEAT TREAT 180 - 200 KSI) (c) Chord - Outboard Strut - Left 2 65B94115-3 (c) Chord - Outboard Strut - Right 2 65B94115-4 (a) Refer to the Qualified Products List at the end of the Boeing Material Specification (BMS) for supplier data. (b) Required only if cracks are found and web needs to be replaced. QTY is for airplane if parts in both struts need replacement. (c) Required only if cracks are found and chord needs to be replaced. QTY is for airplane if parts in both struts need replacement.
3. Parts Modified and Reidentified None.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: March 14, 2013 747-54A2237 20 of 59 **BOEING SERVICE BULLETIN 747-54A2237 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.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: March 14, 2013 747-54A2237 21 of 59 **BOEING SERVICE BULLETIN 747-54A2237 ALERT**  **ALERT**Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: March 14, 2013 747-54A2237 22 of 59 **BOEING SERVICE BULLETIN 747-54A2237 ALERT**  **ALERT**

BLANK PAGE**3. ACCOMPLISHMENT INSTRUCTIONS A. GENERAL INFORMATION**  **CAUTION:** KEEP THE WORK AREA, WIRES AND ELECTRICAL BUNDLES CLEAN OF METAL PARTICLES OR CONTAMINATION WHEN YOU USE TOOLS. UNWANTED MATERIAL, METAL PARTICLES OR CONTAMINATION CAUGHT IN WIRE BUNDLES CAN CAUSE DAMAGE TO THE BUNDLES. DAMAGED WIRE BUNDLES CAN CAUSE SPARKS OR OTHER ELECTRICAL DAMAGE. **NOTE:** 1. Manual titles are referred to by acronyms. Refer to Paragraph 1.J., References, for definition of the acronyms. 2. Obey all of the warnings and cautions given in the specified manual sections. 3. Unless shown differently, these dimensions and tolerances are used: – Linear dimensions are in inches – Tolerance on linear dimensions, other than rivet and bolt edge margins, is plus or minus 0.03 inch – 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 4. Use the approved fastener and process material substitutions in accordance with SRM Chapter 51. 5. Refer to the SWPM 20-10-11 and SWPM 20-10-12 for the wire installation procedures, and SWPM 20-10-19 for the wire separation requirements, as accepted procedures. 6. The necessary conditions for selection of clamp type and size are included in SWPM 20-10-12. If any wire bundle support clamp specified in this service bulletin does not make a correct fit on the wire bundle, refer to SWPM 20-10-12 as an accepted procedure to select a clamp that fits correctly. 7. If the length of any fastener specified in this service bulletin does not meet installation standards given in SRM Chapter 51, then a fastener of the same specification, or an approved substitute, with a length which meets the installation standards given in SRM Chapter 51 may be used. In addition, washers may be installed for fastener grip length in accordance with SRM Chapter 51. 8. 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. 9. HFEC refers to a High Frequency Eddy Current Inspection. DET refers to a Detailed Inspection.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: March 14, 2013 747-54A2237 23 of 59 **BOEING SERVICE BULLETIN 747-54A2237 ALERT**  **ALERT**10. 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. 11. 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. 12. 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. 13. Where the work instructions include installation of a kept part, a new or serviceable part with the same part number can be installed as an alternative to the kept part. 14. This service bulletin includes functional test procedures for the systems changed by this service bulletin. More functional tests can possibly be necessary in accordance with standard maintenance practices because of interruption to other airplane systems. 15. Shaded areas in Figures are to separate the non-critical and non-authoritative information from the critical and authoritative information. 16. When more than one OPTION is given for a CONDITION, do only one of the OPTION numbers. When more than one ACTION is given for a CONDITION number or an OPTION number, do all of the ACTION numbers for that CONDITION number or OPTION number. 17. The compliance times for the actions in Paragraph 3.B., WORK INSTRUCTIONS are in Paragraph 1.E., Compliance. 18. The CONDITIONS, ACTIONS and OPTIONS shown apply to each strut independently. **B. WORK INSTRUCTIONS Lower Spar chord and web, Detailed (DET) and High Frequency Eddy Current (HFEC) Inspection**  **before the accomplishment of PART 2: LOWER SPAR CHORD MODIFICATION** 1. Do PART 1: LOWER SPAR DET AND HFEC INSPECTION for cracks. 2. Do PART 1: LOWER SPAR DET AND HFEC INSPECTION for cracks and PART 2: LOWER SPAR CHORD MODIFICATION. **NOTE:** PART 2: LOWER SPAR CHORD MODIFICATION is terminating action for PART 1: LOWER SPAR DET AND HFEC INSPECTION. See Lower Spar Web, Detailed (DET) Inspection after the accomplishment of PART 2: LOWER SPAR CHORD MODIFICATION for inspections required after the accomplishment of PART 2: LOWER SPAR CHORD MODIFICATION.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: March 14, 2013 747-54A2237 24 of 59 **BOEING SERVICE BULLETIN 747-54A2237 ALERT**  **ALERT CONDITION 1: NO CRACK FOUND**  a. OPTION 1: Repeat PART 1: LOWER SPAR DET AND HFEC INSPECTION for cracks. b. OPTION 2: Do PART 1: LOWER SPAR DET AND HFEC INSPECTION for cracks and PART 2: LOWER SPAR CHORD MODIFICATION. **NOTE:** PART 2: LOWER SPAR CHORD MODIFICATION is terminating action for PART 1: LOWER SPAR DET AND HFEC INSPECTION. See Lower Spar Web, Detailed (DET) Inspection after the accomplishment of PART 2: LOWER SPAR CHORD MODIFICATION for inspections required after the accomplishment of PART 2: LOWER SPAR CHORD MODIFICATION. **CONDITION 2: ANY CRACK FOUND** a. CONDITION 2 (ACTION 1): Repair any part with crack in accordance with PART 3: LOWER SPAR REPAIR. b. CONDITION 2 (ACTION 2): Do PART 2: LOWER SPAR MODIFICATION. **NOTE:** PART 2: LOWER SPAR CHORD MODIFICATION is terminating action for PART 1: LOWER SPAR DET AND HFEC INSPECTION. See Lower Spar Web, Detailed (DET) Inspection after the accomplishment of PART 2: LOWER SPAR CHORD MODIFICATION for inspections required after the accomplishment of PART 2: LOWER SPAR CHORD MODIFICATION. **Lower Spar Web, Detailed (DET) Inspection after the accomplishment of PART 2: LOWER SPAR CHORD MODIFICATION**  1. Do PART 4: LOWER SPAR DET INSPECTION for cracks. **CONDITION 3: NO CRACK FOUND** a. Repeat PART 4: LOWER SPAR DET INSPECTION for cracks. **CONDITION 4: ANY CRACK FOUND** a. CONDITION 4 (ACTION 1): Repair in accordance with PART 3: LOWER SPAR REPAIR. b. CONDITION 4 (ACTION 2): Do PART 4: LOWER SPAR DET INSPECTION for cracks. **PART 1: LOWER SPAR DET AND HFEC INSPECTION** 1. Open access panels below. Refer to 747-100/200/300 AMM 12-09-09 for location of panels.
**Strut no. 4 Strut no. 1**  483BL 453BL 2. Open side cowl. Refer to 747-100/200/300 AMM 71-11-04 as an accepted procedure.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: March 14, 2013 747-54A2237 25 of 59 **BOEING SERVICE BULLETIN 747-54A2237 ALERT**  **ALERT**3. Do a DET and HFEC inspection for cracks in the lower spar chords and a DET of the web for cracks in accordance with the figures below.
**Strut no. 4 Strut no. 1**  FIGURE 4 FIGURE 1 4. Close side cowl. Refer to 747-100/200/300 AMM 71-11-04 as an accepted procedure. 5. Do a DET inspection for cracks in the lower spar chords and web in accordance with the figures below.
**Strut no. 4 Strut no. 1**  FIGURE 5 FIGURE 2 6. Close access panels below. Refer to 747-100/200/300 AMM 12-09-09 for location of panels.
**Strut no. 4 Strut no. 1**  483BL 453BL 7. Put airplane in serviceable condition. **PART 2: LOWER SPAR CHORD MODIFICATION** 1. Open access panels below. Refer to 747-100/200/300 AMM 12-09-09 for location of panels.
**Strut no. 4 Strut no. 1**  483BL 453BL 2. Remove left side cowl (recommended),or open side cowls. Refer to 747-100/200/300 AMM 71-11-04 as an accepted procedure. 3. Replace fasteners in lower chords in accordance with the figures below.
**Strut no. 4 Strut no. 1**  FIGURE 6 FIGURE 3 4. Install left side cowl or close side cowls. Refer to 747-100/200/300 AMM 71-11-04 as an accepted procedure. 5. Close access panels below. Refer to 747-100/200/300 AMM 12-09-09 for location of panels.
**Strut no. 4 Strut no. 1**  483BL 453BL 6. Put airplane in serviceable condition.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: March 14, 2013 747-54A2237 26 of 59 **BOEING SERVICE BULLETIN 747-54A2237 ALERT**  **ALERT PART 3: LOWER SPAR REPAIR**  1. Repair any crack in the lower spar web in accordance with 747-100/200/300 SRM 54-11-03 (CF6-45/50 series engines) or 747-100/200/300 SRM 54-12-03 (JT9D-70 series engines). Contact The Boeing Company for repair instructions for the lower spar chords and do the repair. **PART 4: LOWER SPAR DET INSPECTION** 1. Open access panels below. Refer to 747-100/200/300 AMM 12-09-09 for location of panels.
**Strut no. 4 Strut no. 1**  483BL 453BL 2. Open side cowl. Refer to 747-100/200/300 AMM 71-11-04 as an accepted procedure. 3. Do a DET inspection for cracks in the lower spar web and chord in accordance with the figures below.
**Strut no. 4 Strut no. 1**  FIGURE 9 FIGURE 7 4. Close side cowl. Refer to 747-100/200/300 AMM 71-11-04 as an accepted procedure. 5. Do a DET inspection for cracks in the lower spar web and chord in accordance with the figures below.
**Strut no. 4 Strut no. 1**  FIGURE 10 FIGURE 8 6. Close access panels below. Refer to 747-100/200/300 AMM 12-09-09 for location of panels.
**Strut no. 4 Strut no. 1**  483BL 453BL 7. Put airplane in serviceable condition.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: March 14, 2013 747-54A2237 27 of 59 **BOEING SERVICE BULLETIN 747-54A2237 ALERT**  **ALERT FIGURE 1: STRUT NO. 1 - LOWER SPAR - LOWER SURFACE DET AND HFEC INSPECTION**  **(SHEET 1 OF 3)** Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: March 14, 2013 747-54A2237 28 of 59 **BOEING SERVICE BULLETIN 747-54A2237 ALERT**  **ALERT FIGURE 1: STRUT NO. 1 - LOWER SPAR - LOWER SURFACE DET AND HFEC INSPECTION**  **(SHEET 2 OF 3)** Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: March 14, 2013 747-54A2237 29 of 59 **BOEING SERVICE BULLETIN 747-54A2237 ALERT**  **ALERT**The step numbers shown below agree with the numbers shown in the circle symbols in the figure. The QTY numbers shown below are the number of parts necessary for each side of airplane.
**More Data Qty**  **Identification Name**  **Task Step**  Do a DET of the indicated area for cracks. 2
- Lower Spar Chord Inspect 1
Do a DET of the visible surfaces of the indicated area for cracks. 1
- Lower Spar Web Inspect 2 Do a HFEC inspection for cracks of the indicated area at the edge of the chord in accordance with 747 NDT Manual Part 6, 51-00-00, Procedure 13 or 24. 2
- Lower Spar Chord Inspect 3

Do a HFEC inspection for cracks around the indicated fasteners in accordance with 747 NDT Manual Part 6, 51-00-00, Procedure 13 or 24. 6
- Lower Spar Chord Inspect 4

**FIGURE 1: STRUT NO. 1 - LOWER SPAR - LOWER SURFACE DET AND HFEC INSPECTION (SHEET 3 OF 3)**  Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: March 14, 2013 747-54A2237 30 of 59 **BOEING SERVICE BULLETIN 747-54A2237 ALERT**  **ALERT FIGURE 2: STRUT NO. 1 - LOWER SPAR - INTERIOR SURFACES DET INSPECTION**  **(SHEET 1 OF 3)** Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: March 14, 2013 747-54A2237 31 of 59 **BOEING SERVICE BULLETIN 747-54A2237 ALERT**  **ALERT FIGURE 2: STRUT NO. 1 - LOWER SPAR - INTERIOR SURFACES DET INSPECTION**  **(SHEET 2 OF 3)** Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: March 14, 2013 747-54A2237 32 of 59 **BOEING SERVICE BULLETIN 747-54A2237 ALERT**  **ALERT**The step numbers shown below agree with the numbers shown in the circle symbols in the figure. The QTY numbers shown below are the number of parts necessary for each side of airplane.
**More Data Qty**  **Identification Name**  **Task Step**  Do a DET of the indicated area for cracks. 2
- Lower Spar Chord Inspect 1
Do a DET of the visible surfaces of the indicated area for cracks. 1
- Lower Spar Web Inspect 2

**FIGURE 2: STRUT NO. 1 - LOWER SPAR - INTERIOR SURFACES DET INSPECTION (SHEET 3 OF 3)**  Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: March 14, 2013 747-54A2237 33 of 59 **BOEING SERVICE BULLETIN 747-54A2237 ALERT**  **ALERT FIGURE 3: STRUT NO. 1 - LOWER SPAR - HFEC INSPECTION AND FASTENER REPLACEMENT**  **(SHEET 1 OF 4)** Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: March 14, 2013 747-54A2237 34 of 59 **BOEING SERVICE BULLETIN 747-54A2237 ALERT**  **ALERT FIGURE 3: STRUT NO. 1 - LOWER SPAR - HFEC INSPECTION AND FASTENER REPLACEMENT**  **(SHEET 2 OF 4)** Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: March 14, 2013 747-54A2237 35 of 59 **BOEING SERVICE BULLETIN 747-54A2237 ALERT**  **ALERT**The step numbers shown below agree with the numbers shown in the circle symbols in the figure. The QTY numbers shown below are the number of parts necessary for each side of airplane.
**More Data Qty**  **Identification Name**  **Task Step**  6
- Fastener Remove 1 Do an open-hole HFEC inspectionfor cracks in the chord in accordance with 747 NDT Manual Part 6, 51-00-00, Procedure 2 or 19. (a) 6
- Fastener Hole Inspect 2

Do a full 1/16 inch oversize insurance cut. Contact The Boeing Company for repair instructions and do the repair if oversize fasteners were originally installed and the insurance cut will exceed the hole size in the fastener code table. 6
- Fastener Hole Drill / Ream 3

6
- Fastener Install (New) 4 Wet install fastener with sealant, BMS 5-63. - BMS 5-63 Sealant Apply (a) If any crack is found, Contact The Boeing Company for repair instructions and do the repair. 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.

**FIGURE 3: STRUT NO. 1 - LOWER SPAR - HFEC INSPECTION AND FASTENER REPLACEMENT (SHEET 3 OF 4)**  Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: March 14, 2013 747-54A2237 36 of 59 **BOEING SERVICE BULLETIN 747-54A2237 ALERT**  **ALERT More Data**  **Hole Dia Qty**  **Identification Name**  **Code** Wet install with sealant, BMS 5-63. 0.2495 - 0.2515 6 BACB30MB8A4U BOLT, PROTRUDING HD A

- 6 BACC30BH8S COLLAR

**FIGURE 3: STRUT NO. 1 - LOWER SPAR - HFEC INSPECTION AND FASTENER REPLACEMENT (SHEET 4 OF 4)**  Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: March 14, 2013 747-54A2237 37 of 59 **BOEING SERVICE BULLETIN 747-54A2237 ALERT**  **ALERT FIGURE 4: STRUT NO. 4 - LOWER SPAR - LOWER SURFACE DET AND HFEC INSPECTION**  **(SHEET 1 OF 3)** Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: March 14, 2013 747-54A2237 38 of 59 **BOEING SERVICE BULLETIN 747-54A2237 ALERT**  **ALERT FIGURE 4: STRUT NO. 4 - LOWER SPAR - LOWER SURFACE DET AND HFEC INSPECTION**  **(SHEET 2 OF 3)** Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: March 14, 2013 747-54A2237 39 of 59 **BOEING SERVICE BULLETIN 747-54A2237 ALERT**  **ALERT**The step numbers shown below agree with the numbers shown in the circle symbols in the figure. The QTY numbers shown below are the number of parts necessary for each side of airplane.
**More Data Qty**  **Identification Name**  **Task Step**  Do a DET of the indicated area for cracks. 2
- Lower Spar Chord Inspect 1
Do a DET of the visible surfaces of the indicated area for cracks. 1
- Lower Spar Web Inspect 2 Do a HFEC inspection for cracks of the indicated area at the edge of the chord in accordance with 747 NDT Manual Part 6, 51-00-00, Procedure 13 or 24. 2
- Lower Spar Chord Inspect 3

Do a HFEC inspection for cracks around the indicated fasteners in accordance with 747 NDT Manual Part 6, 51-00-00, Procedure 13 or 24. 6
- Lower Spar Chord Inspect 4

**FIGURE 4: STRUT NO. 4 - LOWER SPAR - LOWER SURFACE DET AND HFEC INSPECTION (SHEET 3 OF 3)**  Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: March 14, 2013 747-54A2237 40 of 59 **BOEING SERVICE BULLETIN 747-54A2237 ALERT**  **ALERT FIGURE 5: STRUT NO. 4 - LOWER SPAR - INTERIOR SURFACES DET INSPECTION**  **(SHEET 1 OF 3)** Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: March 14, 2013 747-54A2237 41 of 59 **BOEING SERVICE BULLETIN 747-54A2237 ALERT**  **ALERT FIGURE 5: STRUT NO. 4 - LOWER SPAR - INTERIOR SURFACES DET INSPECTION**  **(SHEET 2 OF 3)** Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: March 14, 2013 747-54A2237 42 of 59 **BOEING SERVICE BULLETIN 747-54A2237 ALERT**  **ALERT**The step numbers shown below agree with the numbers shown in the circle symbols in the figure. The QTY numbers shown below are the number of parts necessary for each side of airplane.
**More Data Qty**  **Identification Name**  **Task Step**  Do a DET of the indicated area for cracks. 2
- Lower Spar Chord Inspect 1
Do a DET of the visible surfaces of the indicated area for cracks. 1
- Lower Spar Web Inspect 2

**FIGURE 5: STRUT NO. 4 - LOWER SPAR - INTERIOR SURFACES DET INSPECTION (SHEET 3 OF 3)**  Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: March 14, 2013 747-54A2237 43 of 59 **BOEING SERVICE BULLETIN 747-54A2237 ALERT**  **ALERT FIGURE 6: STRUT NO. 4 - LOWER SPAR - HFEC INSPECTION AND FASTENER REPLACEMENT**  **(SHEET 1 OF 4)** Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: March 14, 2013 747-54A2237 44 of 59 **BOEING SERVICE BULLETIN 747-54A2237 ALERT**  **ALERT FIGURE 6: STRUT NO. 4 - LOWER SPAR - HFEC INSPECTION AND FASTENER REPLACEMENT**  **(SHEET 2 OF 4)** Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: March 14, 2013 747-54A2237 45 of 59 **BOEING SERVICE BULLETIN 747-54A2237 ALERT**  **ALERT**The step numbers shown below agree with the numbers shown in the circle symbols in the figure. The QTY numbers shown below are the number of parts necessary for each side of airplane.
**More Data Qty**  **Identification Name**  **Task Step**  6
- Fastener Remove 1 Do an open-hole HFEC inspectionfor cracks in the chord in accordance with 747 NDT Manual Part 6, 51-00-00, Procedure 2 or 19. (a) 6
- Fastener Hole Inspect 2

Do a full 1/16 inch oversize insurance cut. Contact The Boeing Company for repair instructions and do the repair if oversize fasteners were originally installed and the insurance cut will exceed the hole size in the fastener code table. 6
- Fastener Hole Drill / Ream 3

6
- Fastener Install (New) 4 Wet install fastener with sealant, BMS 5-63. - BMS 5-63 Sealant Apply (a) If any crack is found, Contact The Boeing Company for repair instructions and do the repair. 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.

**FIGURE 6: STRUT NO. 4 - LOWER SPAR - HFEC INSPECTION AND FASTENER REPLACEMENT (SHEET 3 OF 4)**  Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: March 14, 2013 747-54A2237 46 of 59 **BOEING SERVICE BULLETIN 747-54A2237 ALERT**  **ALERT More Data**  **Hole Dia Qty**  **Identification Name**  **Code** Wet install with sealant, BMS 5-63. 0.2495 - 0.2515 6 BACB30MB8A4U BOLT, PROTRUDING HD A

- 6 BACC30BH8S COLLAR

**FIGURE 6: STRUT NO. 4 - LOWER SPAR - HFEC INSPECTION AND FASTENER REPLACEMENT (SHEET 4 OF 4)**  Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: March 14, 2013 747-54A2237 47 of 59 **BOEING SERVICE BULLETIN 747-54A2237 ALERT**  **ALERT FIGURE 7: STRUT NO. 1 - LOWER SPAR - LOWER SURFACE DET INSPECTION**  **(SHEET 1 OF 3)** Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: March 14, 2013 747-54A2237 48 of 59 **BOEING SERVICE BULLETIN 747-54A2237 ALERT**  **ALERT FIGURE 7: STRUT NO. 1 - LOWER SPAR - LOWER SURFACE DET INSPECTION**  **(SHEET 2 OF 3)** Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: March 14, 2013 747-54A2237 49 of 59 **BOEING SERVICE BULLETIN 747-54A2237 ALERT**  **ALERT**The step numbers shown below agree with the numbers shown in the circle symbols in the figure. The QTY numbers shown below are the number of parts necessary for each side of airplane.
**More Data Qty**  **Identification Name**  **Task Step**  Do a DET of the visible surfaces of the indicated area for cracks. 1
- Lower Spar Web Inspect 1
Do a DET of the visible surfaces of the indicated area for cracks. 2
- Lower Spar Chord Inspect

**FIGURE 7: STRUT NO. 1 - LOWER SPAR - LOWER SURFACE DET INSPECTION (SHEET 3 OF 3)**  Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: March 14, 2013 747-54A2237 50 of 59 **BOEING SERVICE BULLETIN 747-54A2237 ALERT**  **ALERT FIGURE 8: STRUT NO. 1 - INTERIOR SURFACES DET INSPECTION**  **(SHEET 1 OF 3)** Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: March 14, 2013 747-54A2237 51 of 59 **BOEING SERVICE BULLETIN 747-54A2237 ALERT**  **ALERT FIGURE 8: STRUT NO. 1 - INTERIOR SURFACES DET INSPECTION**  **(SHEET 2 OF 3)** Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: March 14, 2013 747-54A2237 52 of 59 **BOEING SERVICE BULLETIN 747-54A2237 ALERT**  **ALERT**The step numbers shown below agree with the numbers shown in the circle symbols in the figure. The QTY numbers shown below are the number of parts necessary for each side of airplane.
**More Data Qty**  **Identification Name**  **Task Step**  Do a DET of the visible surfaces of the indicated area for cracks. 1
- Lower Spar Web Inspect 1
Do a DET of the visible surfaces of the indicated area for cracks. 2
- Lower Spar Chord Inspect

**FIGURE 8: STRUT NO. 1 - INTERIOR SURFACES DET INSPECTION (SHEET 3 OF 3)**  Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: March 14, 2013 747-54A2237 53 of 59 **BOEING SERVICE BULLETIN 747-54A2237 ALERT**  **ALERT FIGURE 9: STRUT NO. 4 - LOWER SPAR - LOWER SURFACE DET INSPECTION**  **(SHEET 1 OF 3)** Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: March 14, 2013 747-54A2237 54 of 59 **BOEING SERVICE BULLETIN 747-54A2237 ALERT**  **ALERT FIGURE 9: STRUT NO. 4 - LOWER SPAR - LOWER SURFACE DET INSPECTION**  **(SHEET 2 OF 3)** Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: March 14, 2013 747-54A2237 55 of 59 **BOEING SERVICE BULLETIN 747-54A2237 ALERT**  **ALERT**The step numbers shown below agree with the numbers shown in the circle symbols in the figure. The QTY numbers shown below are the number of parts necessary for each side of airplane.
**More Data Qty**  **Identification Name**  **Task Step**  Do a DET of the visible surfaces of the indicated area for cracks. 1
- Lower Spar Web Inspect 1
Do a DET of the visible surfaces of the indicated area for cracks. 2
- Lower Spar Chord Inspect

**FIGURE 9: STRUT NO. 4 - LOWER SPAR - LOWER SURFACE DET INSPECTION (SHEET 3 OF 3)**  Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: March 14, 2013 747-54A2237 56 of 59 **BOEING SERVICE BULLETIN 747-54A2237 ALERT**  **ALERT FIGURE 10: STRUT NO. 4 - LOWER SPAR WEB - INTERIOR SURFACES DET INSPECTION**  **(SHEET 1 OF 3)** Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: March 14, 2013 747-54A2237 57 of 59 **BOEING SERVICE BULLETIN 747-54A2237 ALERT**  **ALERT FIGURE 10: STRUT NO. 4 - LOWER SPAR WEB - INTERIOR SURFACES DET INSPECTION**  **(SHEET 2 OF 3)** Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: March 14, 2013 747-54A2237 58 of 59 **BOEING SERVICE BULLETIN 747-54A2237 ALERT**  **ALERT**The step numbers shown below agree with the numbers shown in the circle symbols in the figure. The QTY numbers shown below are the number of parts necessary for each side of airplane.
**More Data Qty**  **Identification Name**  **Task Step**  Do a DET of the visible surfaces of the indicated area for cracks. 1
- Lower Spar Web Inspect 1
Do a DET of the visible surfaces of the indicated area for cracks. 2
- Lower Spar Chord Inspect

**FIGURE 10: STRUT NO. 4 - LOWER SPAR WEB - INTERIOR SURFACES DET INSPECTION (SHEET 3 OF 3)**  Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: March 14, 2013 747-54A2237 59 of 59 **BOEING SERVICE BULLETIN 747-54A2237 ALERT**  **ALERT**