### Commercial **Airplanes** 

# 777 Service Bulletin **SPECIAL ATTENTION Number: 777-54-0028**  Original Issue: May 25, 2012 Revision 1: December 10, 2013 ATA System: 5451 **SUBJECT:** NACELLES / PYLONS - Nacelle Strut - PW4000 Forward Dry Bay and Forward Engine Mount Bulkhead - Inspection 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 © 2012 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 Unpublished Work.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: May 25, 2012 777-54-0028 Revision 1: December 10, 2013 1 of 49 3.0Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 25, 2012 777-54-0028 Revision 1: December 10, 2013 2 of 49 **BOEING SERVICE BULLETIN 777-54-0028**

BLANK PAGE**Table of Contents** Revision Transmittal Sheet............................................ 5 Summary...................................................... 9 1. PLANNING INFORMATION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 A. Effectivity. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 1. Airplanes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 2. Spares Affected . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 B. Concurrent Requirements. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 C. Reason. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 D. Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 E. Compliance. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 F. Approval . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 G. Manpower . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 H. Weight and Balance Changes. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 I. Electrical Load Data. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 J. References. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 1. Existing Data: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 2. Data Supplied with this Service Bulletin:. . . . . . . . . . . . . . . . . . . . . . . . . . . 21 3. Installation Drawings Used in the Preparation of this Service Bulletin:. . . . . . . . . . . 21 K. Publications Affected . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 L. Interchangeability and Intermixability of Parts. . . . . . . . . . . . . . . . . . . . . . . . . . . 21 M. Software Accomplishment Summary. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 2. MATERIAL INFORMATION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 A. Material - Price and Availability. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 B. Industry Support Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 C. Parts Necessary for Each Airplane. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 1. Kits/Parts. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 2. Parts and Materials Supplied by the Operator. . . . . . . . . . . . . . . . . . . . . . . . 23 3. Parts Modified and Reidentified. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 4. Parts Removed and Not Replaced. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 D. Parts Necessary to Change Spares. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 E. Special Tooling - Price and Availability. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 F. Special Tooling Necessary to do this Service Bulletin. . . . . . . . . . . . . . . . . . . . . . . 24 3. ACCOMPLISHMENT INSTRUCTIONS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 A. GENERAL INFORMATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 B. WORK INSTRUCTIONS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 FIGURE 1: STRUT NO. 1 - FORWARD DRY BAY INTERIOR - GVI INSPECTION. . . . . . . . . . . 30 FIGURE 2: STRUT NO. 1 - FORWARD DRY BAY INTERIOR - DET INSPECTION. . . . . . . . . . 32 FIGURE 3: STRUT NO. 1 - FORWARD ENGINE MOUNT BULKHEAD FITTING - DET AND HFEC INSPECTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36 FIGURE 4: STRUT NO. 2 - FORWARD DRY BAY INTERIOR - GVI INSPECTION. . . . . . . . . . . 38 FIGURE 5: STRUT NO. 2 - FORWARD DRY BAY INTERIOR - DET INSPECTION. . . . . . . . . . 40 FIGURE 6: STRUT NO. 2 - FORWARD ENGINE MOUNT BULKHEAD FITTING - DET AND HFEC INSPECTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44 APPENDIX A: CLEANING AND REFINISHING OF STRUT FWD DRY BAY DETAILS. . . . . . . . . . 46

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 25, 2012 777-54-0028 Revision 1: December 10, 2013 3 of 49 **BOEING SERVICE BULLETIN 777-54-0028**Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 25, 2012 777-54-0028 Revision 1: December 10, 2013 4 of 49 **BOEING SERVICE BULLETIN 777-54-0028**

BLANK PAGE

### Commercial **Airplanes** 

# 777 Service Bulletin **SPECIAL ATTENTION Revision Transmittal Sheet**  **Number: 777-54-0028** Original Issue: May 25, 2012 Revision 1: December 10, 2013 ATA System: 5451 **SUBJECT:** NACELLES / PYLONS - Nacelle Strut - PW4000 Forward Dry Bay and Forward Engine Mount Bulkhead - Inspection This revision includes all pages of the service bulletin. **COMPLIANCE INFORMATION RELATED TO THIS REVISION** Federal Aviation Administration (FAA) Airworthiness Directive AD 2013-11-14 is related to this service bulletin. Airplanes WC587, WC593, WC594, and WC595 were added to the service bulletin effectivity as Group 2 Airplanes. These airplanes should accomplish the initial inspection at the compliance time in accordance with Paragraph 1.E., Compliance. No more work is necessary on the airplanes inspected in accordance with the original issue of this service bulletin. These airplanes should repeat the inspection at the repeat interval in accordance with Paragraph 1.E., Compliance. **REASON FOR REVISION** This revision is sent to: 1. Add airplanes WC587, WC593, WC594, and WC595 to the effectivity of this service bulletin as Group 2 Airplanes. Subsequent to the release of this service bulletin it was determined that a production change that was to be installed on these airplanes that would have terminated the inspections in this service bulletin could not be installed. Therefore the inspection of these airplanes in accordance with this service bulletin is required. Group 2 Airplanes are the same as Group 1 Airplanes, except for the compliance time for the initial inspection. 2. Revise compliance table and work instructions to show that finish restoration is not required until the repairs are required. 3. Clarify that hydraulic fluid contamination includes hydraulic fluid contamination in its liquid (fluid), vapor, and/or solid (coked) form. 4. Add optional leveling compound. 5. Add an alternate method of leveling compound repair for small areas that uses sealant and does not require airplane leveling. These sections were changed:

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 25, 2012 777-54-0028 Revision 1: December 10, 2013 5 of 491. Summary: a. Background - Revise to show hydraulic fluid contamination can be in the form of a liquid (fluid), vapor, or solid (coke). Revise hydraulic fluid to hydraulic fluid contamination at 4 locations. b. Action - Revise Part 1 to show hydraulic fluid contamination can be in the form of a liquid (fluid), vapor, or solid (coke) and blistered and/or peeling primer is a sign of hydraulic fluid contamination. c. Compliance - Add FAA AD. 2. Planning Information: a. Paragraph 1.C., Reason: (1) Revise to show hydraulic fluid contamination can be in the form of a liquid (fluid), vapor, or solid (coke). Revise hydraulic fluid to hydraulic fluid contamination at 4 locations. (2) Add Reason for this revision information. b. Paragraph 1.D., Description: (1) Revise Part 1 to show hydraulic fluid contamination can be in the form of a liquid (fluid), vapor, or solid (coke) and blistered and/or peeling primer is a sign of hydraulic fluid contamination. (2) Add "Compliance Information Related to This Revision". (3) add Affected Maintenance Zone Table for Group 2 Airplanes. c. Paragraph 1.E., Compliance: (1) Add FAA AD. (2) Revise Table 1, row 1 to limit condition to Group 1 Airplanes. (3) Add Table 1, row 2 for Group 2 Airplanes. Group 2 Airplanes have initial compliance from revision 1 date, instead of from the effective date of the AD. (4) Revise to show hydraulic fluid contamination can be in the form of a liquid (fluid), vapor, or solid (coke) in multiple locations in Table 1. (5) Clarify that the compliance time in Table 1, second action for condition 2B is from the time Condition 2B is found. (6) Clarify that restore sealant, primer and leveling compound can be accomplished at the same compliance time as the repair in Table 1, second action for condition 2B. (7) Clarify that restoration of sealant, primer, and leveling compound can be accomplished at the same compliance time as the repair in Table 1, first action for condition 2C. d. Paragraph 1.F., Approval: (1) Add statement approving this service bulletin as an alternate method of compliance (AMOC) to FAA AD.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 25, 2012 777-54-0028 Revision 1: December 10, 2013 6 of 49 **BOEING SERVICE BULLETIN 777-54-0028**e. Paragraph 1.J.1., Existing Data: (1) Add FAA AD. 3. Material Information: a. Paragraph 2.C.2., Parts and Materials Supplied by the Operator: (1) Add optional leveling compound. Change finishes to sealant, primer, and leveling compound. 4. Accomplishment Instructions: a. Paragraph 3.A., General Information - No Changes b. Paragraph 3.B., Work Instructions: (1) General Work Instructions: (a) Revise to show hydraulic fluid contamination can be in the form of a liquid (fluid), vapor, or solid (coke) in 6 locations. (b) Move restoration of sealant, primer, and leveling compound from Part 2, Step 4 to the second action for condition 2B. Move restoration of sealant, primer, and leveling compound from Part 3, Step 4 to the first action for condition 2C. (2) Part 1: (a) Step 3 - Revise to show hydraulic fluid contamination can be in the form of a liquid (fluid), vapor, or solid (coke). (3) Part 2: (a) Delete Step 4 and move restoration of sealant, primer, and leveling compound to the second action for condition 2B. (4) Part 3: (a) Delete Step 4 and move restoration of sealant, primer, and leveling compound to the first action for condition 2C. (5) FIGURE 1: (a) Illustration: No changes. (b) Step Table: 1) Step 1 - Revise to show hydraulic fluid can be in the form of a liquid (fluid), vapor, or solid (coke). Revise to show that blistered and/or peeling primer is a sign of hydraulic fluid contamination. (6) FIGURE 4: (a) Illustration: No changes.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 25, 2012 777-54-0028 Revision 1: December 10, 2013 7 of 49 **BOEING SERVICE BULLETIN 777-54-0028**(b) Step Table: 1) Step 1 - Revise to show hydraulic fluid can be in the form of a liquid (fluid), vapor, or solid (coke). Revise to show that blistered and/or peeling primer is a sign of hydraulic fluid contamination. (7) APPENDIX A: (a) Illustrations: No changes. (b) Step Table: 1) Note - Add optional sealant repair. 2) Step 7 - Add optional leveling compound. Refer to optional sealant repair. 3) Step 8 - Add optional leveling compound. Refer to optional sealant repair. 4) Step 9 - Add option to use sealant to repair small areas of leveling compound. The option does not require the airplane to be leveled. Vertical lines are put on the left edge of each page, except in Paragraph 1.A., Effectivity, to show the location of important changes. Pages with no vertical lines have no important changes. **REVISION HISTORY** May 25, 2012 Original Issue: December 10, 2013 Revision 1:

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 25, 2012 777-54-0028 Revision 1: December 10, 2013 8 of 49 **BOEING SERVICE BULLETIN 777-54-0028**

### Commercial **Airplanes** 

# 777 Service Bulletin **SPECIAL ATTENTION Summary**  **Number: 777-54-0028** Original Issue: May 25, 2012 Revision 1: December 10, 2013 ATA System: 5451 **SUBJECT:** NACELLES / PYLONS - Nacelle Strut - PW4000 Forward Dry Bay and Forward Engine Mount Bulkhead - Inspection BOEING RECOMMENDS THAT EACH OPERATOR EXAMINE THIS SERVICE BULLETIN IMMEDIATELY. **CONCURRENT REQUIREMENTS** None. **BACKGROUND** Accomplishment of the inspections in this service bulletin will find hydraulic fluid contamination in its liquid (fluid), vapor, and/or solid (coked) form in the strut forward dry bay, before the forward engine mount bulkhead fittings become sufficiently hydrogen embrittled that they can not carry design loads. If hydraulic fluid contamination is on the titanium forward engine mount bulkhead fittings, hydrogen embrittlement of the fittings can occur. When the forward engine mount bulkhead fitting becomes sufficiently hydrogen embrittled it cannot carry design load and loses limit load capability that can lead to the loss or departure of an engine. Similarly, hydrogen embrittlement of the fittings can cause through crack formation across the fitting. Such through cracks might not contain an engine fire and allow the fire to breach into the strut. The forward engine mount bulkhead fitting does not have fire detection or fire suppression capability. Thus, a fire breaching the forward engine mount bulkhead fitting can lead to an uncontained fire in the strut. One operator has reported 5 airplanes with hydraulic fluid residue in the strut forward dry bay. The airplanes had approximately 9,900 to 29,000 flight-cycles and 13,000 to 33,300 flight-hours. The forward engine mount bulkhead fittings are made from titanium and are located near the hot engine core of the engine where temperatures can exceed 270 degrees Fahrenheit. The presence of hydraulic fluid contamination and temperature above 270 degrees Fahrenheit can result in hydrogen embrittlement of the titanium forward engine mount bulkhead fittings. If the forward engine mount bulkhead fittings become sufficiently hydrogen embrittled, they may not be able to carry design loads. It is believed that hydraulic fluid contamination is entering the dry bay through the condensate drain line. The condensate drain connects to the system disconnect box drain lines, which drains hydraulic fluid and fuel from the system disconnect box. The system disconnect box drain hose can clog due to hydraulic fluid coking in the drain lines. This allows hydraulic fluid to back up into strut forward dry bay through the condensate drain line. Boeing Service Bulletin 777-54-0027 addresses blockage of the strut forward drain lines. If a fitting becomes embrittled, fitting and/or strut replacement may be required. If the fitting becomes sufficiently brittle, it may not be able to carry design loads. Inspection of the strut forward dry bay for the presence of hydraulic fluid contamination will help prevent hydrogen embrittlement of the titanium forward engine mount bulkhead fittings. Boeing Fleet Team Digest (FTD) 777 FTD 54-11001 is related to this service bulletin.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 25, 2012 777-54-0028 Revision 1: December 10, 2013 9 of 49Boeing Service Related Problem (SRP) 777-SRP-54-0138 is related to this service bulletin. This table is provided to operators for planning purposes only. Refer to the applicable sections for more information.
**Reference Affected**  **Planning Data** Paragraph 1.A.2., Spares Affected No Spares Affected Paragraph 1.E., Compliance Yes AD Related Paragraph 1.H., Weight and Balance Changes No Weight and Balance Change Paragraph 1.I., Electrical Load Data No Electrical Load Changed Paragraph 1.K., Publications Affected No Publications Affected Paragraph 1.K., Publications Affected No Airplane Flight Operations Affected (Flight CrewOperations Manual and/or FAA Approved Airplane Flight Manual) Paragraph 2.C.1., Kits/Parts No Kits/Parts Required Paragraph 2.C.2., Parts and Materials Supplied by the Operator No Operator Supplied Material Paragraph 2.F., Special Tooling Necessary to do this Service Bulletin No Special Tooling Required

**ACTION** Part 1 - Strut Forward Dry Bay Hydraulic Fluid Contamination GVI Inspection Open the thrust reverser. Remove the strut forward dry bay access door. Do a General Visual Inspection (GVI) for hydraulic fluid contamination in its liquid (fluid), vapor, and/or solid (coked) form. Blistered and/or peeling primer is a sign of hydraulic fluid contamination and the strut forward dry bay is contaminated. Install the strut forward dry bay access door. Close the thrust reverser. Part 2 - Strut Forward Dry Bay Interior DET Inspection Open the thrust reverser. Remove the strut forward dry bay access door. Do a Detailed Inspection (DET) of the interior of the strut forward dry bay for hydraulic fluid coking, heat discoloration, damage to sealant and primer, damage to leveling compound, cracks; and etching or pitting. Clean and restore sealant, primer, and leveling compound of the detail parts in the strut forward dry bay if missing, blistered, peeling, or damaged. Check drain lines and clean or replace drain lines as required. Install the strut forward dry bay access door. Close the thrust reverser. Part 3 - Strut Forward Engine Mount Bulkhead Fitting DET and HFEC Inspection Open the thrust reverser. Remove the strut forward dry bay access door. Do a DET and High Frequency Eddy Current (HFEC) inspection of the strut forward engine mount bulkhead upper and lower fittings for cracks, and etching or pitting. Clean and restore sealant, primer, and leveling compound of the detail parts in the strut forward dry bay if missing, blistered, peeling, or damaged. Check drain lines and clean or replace drain lines as required. Install the strut forward dry bay access door. Close the thrust reverser.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 25, 2012 777-54-0028 Revision 1: December 10, 2013 10 of 49 **BOEING SERVICE BULLETIN 777-54-0028 EFFECTIVITY**  777-200 and -300 Airplanes powered by PW4000 Engines. Refer to Paragraph 1.A.1., Airplanes, for the list of affected airplanes. **COMPLIANCE** Federal Aviation Administration (FAA) Airworthiness Directive AD 2013-11-14 is related to this service bulletin. Refer to Paragraph 1.E., Compliance. **INDUSTRY SUPPORT INFORMATION** Boeing warranty remedies are available for airplanes in warranty as of June 15, 2011. Please refer to Paragraph 2.B., Industry Support Information. **MANPOWER Elapsed Hours**  **Total Task Hours** 3.00 5.00 Part 1 - Strut Forward Dry Bay Hydraulic Fluid Contamination GVI Inspection 12.50 17.00 Part 2 - Strut Forward Dry Bay Interior DET Inspection 12.50 17.00 Part 3 - Strut Forward Engine MountBulkhead Fitting DET and HFEC Inspection
**MATERIAL INFORMATION** Operator Supplied Parts/Materials. Refer to Paragraph 2.A., Material - Price and Availability.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 25, 2012 777-54-0028 Revision 1: December 10, 2013 11 of 49 **BOEING SERVICE BULLETIN 777-54-0028**Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 25, 2012 777-54-0028 Revision 1: December 10, 2013 12 of 49 **BOEING SERVICE BULLETIN 777-54-0028**

### Commercial **Airplanes** 

# 777 Service Bulletin **SPECIAL ATTENTION Number: 777-54-0028**  Original Issue: May 25, 2012 Revision 1: December 10, 2013 ATA System: 5451 **SUBJECT:** NACELLES / PYLONS - Nacelle Strut - PW4000 Forward Dry Bay and Forward Engine Mount Bulkhead - Inspection BOEING RECOMMENDS THAT EACH OPERATOR EXAMINE THIS SERVICE BULLETIN IMMEDIATELY. **1. PLANNING INFORMATION A. Effectivity**  1. Airplanes This service bulletin is for the airplane(s) shown below. Refer to Service Bulletin Index D624W001 Part 3 for Airplane Variable Number, Line Number, and Serial Number data.
**DESCRIPTION CONFIGURATION**  **GROUP** 777-200 and -300 Airplanes line numbers 2 through 1027 powered by Pratt and Whitney (PW) 4000 Engines. - 1
777-200 and -300 Airplanes line numbers 1090 through 1117 powered by Pratt and Whitney (PW) 4000 Engines. - 2

Airplane Models: 777-200, 777-300 **Group Variable Number**  1 WA002 - WA017 1 WA131 - WA137 1 WA171 - WA175 1 WA206 - WA212 1 WA221 - WA223

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 25, 2012 777-54-0028 Revision 1: December 10, 2013 13 of 49**Group Variable Number**  1 WA231 - WA232 1 WA241 - WA250 1 WA261 - WA266 1 WA281 - WA283 1 WA301 - WA304 1 WB051 - WB088 1 WB131 - WB148 1 WB151 - WB155 1 WB366 - WB368 1 WB481 - WB484 1 WB531 - WB537 1 WB551 - WB554 1 WB591 - WB597 1 WC111 - WC120 1 WC371 - WC374 1 WC506 - WC508 1 WC581 1 WC586 2 WC587 1 WC591 - WC592 2 WC593 - WC595 2. Spares Affected None. **B. Concurrent Requirements** None. **C. Reason** Accomplishment of the inspections in this service bulletin will find hydraulic fluid contamination in its liquid (fluid), vapor, or solid (coked) form in the strut forward dry bay, before the forward engine mount bulkhead fittings become sufficiently hydrogen embrittled that they can not carry design loads. If hydraulic fluid contamination is on the titanium forward engine mount bulkhead fittings, hydrogen embrittlement of the fittings can occur. When the forward engine mount bulkhead fitting becomes sufficiently hydrogen embrittled it cannot carry design load and loses limit load capability that can lead to the loss or departure

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 25, 2012 777-54-0028 Revision 1: December 10, 2013 14 of 49 **BOEING SERVICE BULLETIN 777-54-0028**of an engine. Similarly, hydrogen embrittlement of the fittings can cause through crack formation across the fitting. Such through cracks might not contain an engine fire and allow the fire to breach into the strut. The forward engine mount bulkhead fitting does not have fire detection or fire suppression capability. Thus, a fire breaching the forward engine mount bulkhead fitting can lead to an uncontained fire in the strut. One operator has reported 5 airplanes with hydraulic fluid residue in the strut forward dry bay. The airplanes had approximately 9,900 to 29,000 flight-cycles and 13,000 to 33,300 flight-hours. The forward engine mount bulkhead fittings are made from titanium and are located near the hot engine core of the engine where temperatures can exceed 270 degrees Fahrenheit. The presence of hydraulic fluid contamination and temperature above 270 degrees Fahrenheit can result in hydrogen embrittlement of the titanium forward engine mount bulkhead fittings. If the forward engine mount bulkhead fittings become sufficiently hydrogen embrittled, they may not be able to carry design loads. It is believed that hydraulic fluid contamination is entering the dry bay through the condensate drain line. The condensate drain connects to the system disconnect box drain lines, which drains hydraulic fluid and fuel from the system disconnect box. The system disconnect box drain hose can clog due to hydraulic fluid coking in the drain lines. This allows hydraulic fluid to back up into strut forward dry bay through the condensate drain line. Boeing Service Bulletin 777-54-0027 addresses blockage of the strut forward drain lines. If a fitting becomes embrittled, fitting and/or strut replacement may be required. If the fitting becomes sufficiently brittle, it may not be able to carry design loads. Inspection of the strut forward dry bay for the presence of hydraulic fluid contamination will help prevent hydrogen embrittlement of the titanium forward engine mount bulkhead fittings. Boeing Fleet Team Digest (FTD) 777 FTD 54-11001 is related to this service bulletin. Boeing Service Related Problem (SRP) 777-SRP-54-0138 is related to this service bulletin. Revision 1 is sent to: 1. Add airplanes WC587, WC593, WC594, and WC595 to the effectivity of this service bulletin as Group 2 Airplanes. Subsequent to the release of this service bulletin it was determined that a production change that was to be installed on these airplanes that would have terminated the inspections in this service bulletin could not be installed. Therefore the inspection of these airplanes in accordance with this service bulletin is required. Group 2 Airplanes are the same as Group 1 Airplanes, except for the compliance time for the initial inspection. 2. Revise compliance table and work instructions to show that finish restoration is not required until the repairs are required. 3. Clarify that hydraulic fluid contamination includes hydraulic fluid contamination in its liquid (fluid), vapor, and/or solid (coked) form. 4. Add optional leveling compound. 5. Add an alternate method of leveling compound repair for small areas that uses sealant and does not require airplane leveling. **D. Description** Part 1 - Strut Forward Dry Bay Hydraulic Fluid Contamination GVI Inspection

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 25, 2012 777-54-0028 Revision 1: December 10, 2013 15 of 49 **BOEING SERVICE BULLETIN 777-54-0028**Open the thrust reverser. Remove the strut forward dry bay access door. Do a General Visual Inspection (GVI) for hydraulic fluid contamination in its liquid (fluid), vapor, and/or solid (coked) form. Blistered and/or peeling primer is a sign of hydraulic fluid contamination and the strut forward dry bay is contaminated. Install the strut forward dry bay access door. Close the thrust reverser. Part 2 - Strut Forward Dry Bay Interior DET Inspection Open the thrust reverser. Remove the strut forward dry bay access door. Do a Detailed Inspection (DET) of the interior of the strut forward dry bay for hydraulic fluid coking, heat discoloration, damage to sealant and primer, damage to leveling compound, cracks; and etching or pitting. Clean and restore sealant, primer, and leveling compound of the detail parts in the strut forward dry bay if missing, blistered, peeling, or damaged. Check drain lines and clean or replace drain lines as required. Install the strut forward dry bay access door. Close the thrust reverser. Part 3 - Strut Forward Engine Mount Bulkhead Fitting DET and HFEC Inspection Open the thrust reverser. Remove the strut forward dry bay access door. Do a DET and High Frequency Eddy Current (HFEC) inspection of the strut forward engine mount bulkhead upper and lower fittings for cracks, and etching or pitting. Clean and restore sealant, primer, and leveling compound of the detail parts in the strut forward dry bay if missing, blistered, peeling, or damaged. Check drain lines and clean or replace drain lines as required. Install the strut forward dry bay access door. Close the thrust reverser. Revision 1 - Airplanes WC587, WC593, WC594, and WC595 were added to the service bulletin effectivity as Group 2 Airplanes. These airplanes should accomplish the initial inspection at the compliance time in accordance with Paragraph 1.E., Compliance. No more work is necessary on the airplanes inspected in accordance with the original issue of this service bulletin. These airplanes should repeat the inspection at the repeat interval in accordance with Paragraph 1.E., Compliance. The work in this service bulletin is done in the maintenance zone(s) given below. **Group 1:**
**Affected Maintenance Zones Zone**  **Model** 432, 442 777-200, 777-300 **Group 2:**
**Affected Maintenance Zones Zone**  **Model** 432, 442 777-200 **E. Compliance** Federal Aviation Administration (FAA) Airworthiness Directive AD 2013-11-14 is related to this service bulletin. The effective date of AD 2013-11-14 is July 19, 2013.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 25, 2012 777-54-0028 Revision 1: December 10, 2013 16 of 49 **BOEING SERVICE BULLETIN 777-54-0028**Accomplish the required actions, based on the applicable conditions, in Table 1, in accordance with Paragraph 3. Accomplishment Instructions. Accomplish the actions and evaluate the conditions in Table 1 separately for each strut forward dry bay and each forward engine mount bulkhead. The following acronyms are used in Table 1: – GVI for General Visual Inspection. – DET for Detailed Inspection. – HFEC for High Frequency Eddy Current Inspection. – Part 1 for Part 1 - Strut Forward Dry Bay Hydraulic Fluid Contamination GVI Inspection. – Part 2 for Part 2 - Strut Forward Dry Bay Interior DET Inspection. – Part 3 for Part 3 - Strut Forward Engine Mount Bulkhead Fitting DET and HFEC Inspection **Table 1: GVI, DET, and HFEC Inspection of Strut Forward Dry Bay for Hydraulic Fluid Contamination and Forward Engine Mount Bulkhead for Hydrogen Embrittlement.**  **Repeat Interval (Not to Exceed)**  **Compliance Time Action**  **Condition**

- Within 600 flight-cy-cles or 12 Months after the effective date of AD 2013-11-14, whichever occurs first. Do a GVI of the interior of thestrut forward dry bay for hydraulic fluid contamination in its liquid (fluid), vapor, and/or solid (coked) form in accordance with Part 1. Group 1 Airplanes

- Within 600 flight-cy-cles or 12 Months after the Revision 1 date of this service bulletin, whichever occurs first. Do a GVI of the interior of thestrut forward dry bay for hydraulic fluid contamination in its liquid (fluid), vapor, and/or solid (coked) form in accordance with Part 1. Group 2 Airplanes

1,200 Flight-cycles. - Repeat GVI of the interior of thestrut forward dry bay for hydraulic fluid contamination in its liquid (fluid), vapor, and/or solid (coked) form in accordance with Part 1. Condition 1 - No hydraulic fluid contamination in its liquid (fluid), vapor, and/or solid (coked) form is found.

- Before further flight. Do a DET of the interior of thestrut forward dry bay in accordance with Part 2 for: 1) Hydraulic fluid coking; and 2) Heat discoloration; and 3) Damage to sealant and primer; and 4) Damage to leveling compound; and 5) Cracks; and 6) Etching or pitting. Condition 2 - Hydraulic fluid contamination in its liquid (fluid), vapor, and/or solid (coked) form is found.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 25, 2012 777-54-0028 Revision 1: December 10, 2013 17 of 49 **BOEING SERVICE BULLETIN 777-54-0028 Table 1: GVI, DET, and HFEC Inspection of Strut Forward Dry Bay for Hydraulic Fluid Contamination**  **and Forward Engine Mount Bulkhead for Hydrogen Embrittlement. Repeat Interval**  **(Not to Exceed) Compliance Time**  **Action Condition**  1,200 Flight-cycles. - Repeat GVI of the interior of thestrut forward dry bay for hydraulic fluid contamination in its liquid (fluid), vapor, and/or solid (coked) form in accordance with Part 1. Condition 2A - 1) No hydraulic fluid coking is found; and 2) No heat discoloration is found; and 3) No damage to sealant and primer is found; and 4) No damage to leveling compound is found; and 5) No crack is found; and 6) No etching or pitting is found.

- Before further flight. Do a DET and HFEC of the inte- rior of the strut forward enginemount bulkhead upper and lower fittings for cracks and etching or pitting in accordance with Part 3. Condition 2B - 1) No crack is found; and 2) No etching or pitting is found; and 3) Any of the following is found: ....a) Any Hydraulic fluid coking is found; or ....b) Any heat discoloration is found; or and

- Within 25 flight-cy- cles or 10 days, whichever occurs first, after Condition 2B is found. Contact The Boeing Companyfor repair instructions,do the repair, and restore sealant, primer, and leveling compound. ....c) Any damage to sealant and primer is found; or....d) Any damage to leveling compound is found.

and 1,200 Flight-cycles. - Repeat GVI of the interior of thestrut forward dry bay for hydraulic fluid contamination in its liquid (fluid), vapor, and/or solid (coked) form in accordance with Part 1.

- Before further flight. Contact The Boeing Companyfor repair instructions,do the repair, and restore sealant, primer, and leveling compound. Condition 2C - 1) Any crack is found; or 2) Any etching or pitting is found.

and 1,200 Flight-cycles. - Repeat GVI of the interior of thestrut forward dry bay for hydraulic fluid contamination in its liquid (fluid), vapor, and/or solid (coked) form in accordance with Part 1.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 25, 2012 777-54-0028 Revision 1: December 10, 2013 18 of 49 **BOEING SERVICE BULLETIN 777-54-0028 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. In addition, the Manager of the FAA Seattle Aircraft Certification Office approves the action (i.e. inspection or modification) defined in this service bulletin as an alternative method of compliance to the requirements of paragraph (g) of AD 2013-11-14. All provisions of AD 2013-11-14 that are not specifically referenced in the above statement remain fully applicable and must be complied with. **G. Manpower** The table below shows an estimate of the 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. **Part 1 - Strut Forward Dry Bay Hydraulic Fluid Contamination GVI Inspection Elapsed Hours**  **Task Hours Number of Persons**  **Task** 1.00 2.00 2 Open Access Inspect 0.50 0.50 1 ...FIGURE 1 0.50 0.50 1 ...FIGURE 4 1.00 2.00 2 Close Access 3.00 5.00 TOTAL FOR EACH AIRPLANE **Part 2 - Strut Forward Dry Bay Interior DET Inspection Elapsed Hours**  **Task Hours Number of Persons**  **Task** 1.00 2.00 2 Open Access Inspect

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 25, 2012 777-54-0028 Revision 1: December 10, 2013 19 of 49 **BOEING SERVICE BULLETIN 777-54-0028 Part 2 - Strut Forward Dry Bay Interior DET Inspection**  **Elapsed Hours Task Hours**  **Number of Persons Task**  4.00 4.00 1 ...FIGURE 2 4.00 4.00 1 ...FIGURE 5 2.50 5.00 2 Check Drain Line 1.00 2.00 2 Close Access 12.50 17.00 TOTAL FOR EACH AIRPLANE **Part 3 - Strut Forward Engine Mount Bulkhead Fitting DET and HFEC Inspection Elapsed Hours**  **Task Hours Number of Persons**  **Task** 1.00 2.00 2 Open Access Inspect 4.00 4.00 1 ...FIGURE 3 4.00 4.00 1 ...FIGURE 6 2.50 5.00 2 Check Drain Line 1.00 2.00 2 Close Access 12.50 17.00 TOTAL FOR EACH AIRPLANE **H. Weight and Balance Changes** None. **I. Electrical Load Data** Not changed. **J. References** 1. Existing Data: a. Boeing Service Bulletin 777-54-0027 b. Boeing Service Related Problem (SRP) 777-SRP-54-0138 c. Federal Aviation Administration (FAA) Airworthiness Directive (AD) 2013-11-14 d. Service Bulletin Index D624W001 e. Standard Overhaul Practices Manual (SOPM) 20-30-03, 20-43-03, 20-44-01 f. Standard Wiring Practices Manual (SWPM) 20-10-11, 20-10-12, 20-10-19 g. 777 Aircraft Maintenance Manual (AMM) 06-43-00, 08-21-00, 54-53-01, 54-55-01, 78-31-00

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 25, 2012 777-54-0028 Revision 1: December 10, 2013 20 of 49 **BOEING SERVICE BULLETIN 777-54-0028**h. 777 Fleet Team Digest (FTD) 54-11001 i. 777 Non-Destructive Testing (NDT) Manual Part 6, 51-00-06 2. Data Supplied with this Service Bulletin: None. 3. Installation Drawings Used in the Preparation of this Service Bulletin: None. **K. Publications Affected** 1. Publications: None. 2. Damage Tolerance Based Structural Inspections: Boeing has evaluated the repairs and/or changes in this service bulletin for effects on Fatigue Critical Structure (FCS) and for changes to Damage Tolerance Inspections (DTI) required in the Maintenance Program. This service bulletin affects FCS but no new DTIs are necessary. **L. Interchangeability and Intermixability of Parts** Accomplishment of this service bulletin does not affect interchangeability or intermixability of parts. **M. Software Accomplishment Summary** Not affected.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 25, 2012 777-54-0028 Revision 1: December 10, 2013 21 of 49 **BOEING SERVICE BULLETIN 777-54-0028**Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 25, 2012 777-54-0028 Revision 1: December 10, 2013 22 of 49 **BOEING SERVICE BULLETIN 777-54-0028**

BLANK PAGE**2. MATERIAL INFORMATION A. Material - Price and Availability**  The operator can supply the parts and materials shown in Paragraph 2.C., Parts Necessary for Each Airplane. As an alternative, operators can purchase the parts from Boeing Spares. This service bulletin does not show the Boeing price and supply data. **B. Industry Support Information** Boeing warranty remedies are available for 777 airplanes in warranty as of June 15, 2011. For inspection task hour reimbursement for airplanes in warranty as of that date, send a warranty claim to Boeing Commercial Airplanes Group - Warranties. If the condition described in this service bulletin is found during the inspection for airplanes in warranty as of that date and additional task hours are required, send a warranty claim to Boeing Commercial Airplanes Group - Warranties. Please refer to this service bulletin number and reference the airplane numbers in your purchase order. **C. Parts Necessary for Each Airplane** 1. Kits/Parts None. 2. Parts and Materials Supplied by the Operator The following materials may be required to restore the sealant, primer, and leveling compound in the strut forward dry bay.
**Notes Name**  **QTY Part Number / Specification**  (c) Chemical Conversion Coating 1Oz.

- (a) Primer 1 Pt. BMS 10-79, TYPE III (a) Primer 1 Pt. BMS 10-11, TYPE I (a) Sealant 16 Oz. BMS 5-63 (d) Primer, Silicone 1 Pt. BAC5432, COMPOUND 21, DOW CORNING1201 RTV PRIME COAT (DOW CORNING PR1200 RTV PRIME COAT RED OR SS4004P optional) (d) Leveling Compound, Silicone 2 Qt. BAC5432, COMPOUND 21, XIAMETER RTV- 3110 BASE (DC 3110 OR RTV11 optional) (d) Catalyst 1 Pt. BAC5432, COMPOUND 21, XIAMETER RTV- 3010-S CATALYST (XIAMETER RTV-3000 F CATALYST, S TIN NW, OR RTV9950 optional) (b) Primer, High Temperature 1 Qt. SOPM 20-44-01, Type 51 (a) Refer to the Qualified Products List at the end of the Boeing Material Specification (BMS) for supplier data. (b) Refer to SOPM 20-44-01 for supplier data.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 25, 2012 777-54-0028 Revision 1: December 10, 2013 23 of 49 **BOEING SERVICE BULLETIN 777-54-0028 Notes**  **Name QTY**  **Part Number / Specification** (c) Refer to SOPM 20-43-03 for supplier data. (d) See supplier data below. Leveling Compound, Catalyst, and Primer need to come from same source to ensure compatibility.

– XIAMETER RTV-3110 BASE or DC 3110 (Leveling Compound); XIAMETER RTV-3010-S, XIAMETER RTV-3000 F, or S TIN NW (Catalyst); and DOW CORNING 1201 RTV PRIME COAT or DOW CORNING PR-1200 RTV PRIME COAT RED (Primer) V71984 Dow Corning Corporation 2200 W Salzburg Rd Midland Mi 48640 - 8531 Customer Service/www.dowcorning.com (800) 248-248 – RTV11 (Leveling Compound), RTV9950 (catalyst), and SS4004P 01 P (Primer) V01139 Momentive Performance Materials Inc. 187 Danbury Road Wilton Ct 06897-4122 www.momentive.com (704) 992-4107 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.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 25, 2012 777-54-0028 Revision 1: December 10, 2013 24 of 49 **BOEING SERVICE BULLETIN 777-54-0028 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. Use the approved fastener and process material substitutions in accordance with SRM Chapter 51. 4. 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. 5. 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. 6. A Detailed Inspection (DET) is defined as: An intensive examination of a specific item, installation, or assembly to detect damage, failure, or irregularity. Available lighting is normally supplemented with a direct source of good lighting at an intensity deemed appropriate. Inspection aids such as mirrors, magnifying lenses, etc. may be necessary. Surface cleaning and elaborate procedures may be required. 7. A General Visual Inspection (GVI) is defined as: A visual examination of an interior or exterior area, installation or assembly to detect obvious damage, failure or irregularity. This level of inspection is made from within touching distance unless otherwise specified. A mirror may be necessary to enhance visual access to all exposed surfaces in the inspection area. This level of inspection is made under normally available lighting conditions such as daylight, hangar lighting, flashlight or drop-light and may require removal or opening of access panels or doors. Stands, ladders or platforms may be required to gain proximity to the area being checked. 8. An HFEC inspection is a High Frequency Eddy Current inspection. 9. 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.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 25, 2012 777-54-0028 Revision 1: December 10, 2013 25 of 49 **BOEING SERVICE BULLETIN 777-54-0028**10. 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. 11. 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. 12. Accomplish the actions and evaluate the conditions separately for each strut forward dry bay and each forward engine mount bulkhead. **B. WORK INSTRUCTIONS** 1. Do a GVI of the interior of the strut forward dry bay for hydraulic fluid contamination in its liquid (fluid), vapor, and/or solid (coked) form in accordance with Part 1 - Strut Forward Dry Bay Hydraulic Fluid Contamination GVI Inspection at the compliance time specified in Paragraph 1.E., Compliance. a. Condition 1 - No hydraulic fluid contamination in its liquid (fluid), vapor, and/or solid (coked) form is found. (1) Repeat GVI of the interior of the strut forward dry bay for hydraulic fluid contamination in its liquid (fluid), vapor, and/or solid (coked) form in accordance with Part 1 - Strut Forward Dry Bay Hydraulic Fluid Contamination GVI Inspection at the interval specified in Paragraph 1.E., Compliance. b. Condition 2 - Hydraulic fluid contamination in its liquid (fluid), vapor, and/or solid (coked) form is found. (1) Do a DET of the interior of the strut forward dry bay in accordance with Part 2 - Strut Forward Dry Bay Interior DET Inspection for: 1) Hydraulic fluid coking; and 2) Heat discoloration; and 3) Damage to sealant and primer; and 4) Damage to leveling compound; and 5) Cracks; and 6) Etching or pitting at the compliance time specified in Paragraph 1.E., Compliance. (a) Condition 2A -1) No hydraulic fluid coking is found; and 2) No heat discoloration is found; and 3) No damage to sealant and primer is found; and 4) No damage to leveling compound is found; and 5) No crack is found; and 6) No etching or pitting is found. 1) Repeat GVI of the interior of the strut forward dry bay for hydraulic fluid contamination in its liquid (fluid), vapor, and/or solid (coked) form in accordance with Part 1 - Strut Forward Dry Bay Hydraulic Fluid Contamination GVI Inspection at the interval specified in Paragraph 1.E., Compliance. (b) Condition 2B - 1) No crack is found; and 2) No etching or pitting is found; and 3) Any of the following is found: a) Any Hydraulic fluid coking is found; or b) Any heat discoloration is found; or c) Any damage to sealant and primer is found; or d) Any damage to leveling compound is found.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 25, 2012 777-54-0028 Revision 1: December 10, 2013 26 of 49 **BOEING SERVICE BULLETIN 777-54-0028**1) Do a DET and HFEC of the interior of the strut forward engine mount bulkhead upper and lower fittings for cracks, and etching or pitting in accordance with Part 3 - Strut Forward Engine Mount Bulkhead Fitting DET and HFEC Inspection, at the compliance time specified in Paragraph 1.E., Compliance; and 2) Contact The Boeing Company for repair instructions, do the repair, and restore the sealant, primer, and leveling compound at the compliance time specified in Paragraph 1.E., Compliance. Refer to APPENDIX A as an accepted procedure to clean and restore sealant, primer, and leveling compound of the detail parts in the strut forward dry bay if missing, blistered, peeling, or damaged. 3) Repeat GVI of the interior of the strut forward dry bay for hydraulic fluid contamination in its liquid (fluid), vapor, and/or solid (coked) form in accordance with Part 1 - Strut Forward Dry Bay Hydraulic Fluid Contamination GVI Inspection at the interval specified in Paragraph 1.E., Compliance. (c) Condition 2C - 1) Any crack is found; or 2) Any etching or pitting is found. 1) Contact The Boeing Company for repair instructions, do the repair, and restore the sealant, primer, and leveling compound at the compliance time specified in Paragraph 1.E., Compliance. Refer to APPENDIX A as an accepted procedure to clean and restore sealant, primer, and leveling compound of the detail parts in the strut forward dry bay if missing, blistered, peeling, or damaged. 2) Repeat GVI of the interior of the strut forward dry bay for hydraulic fluid contamination in its liquid (fluid), vapor, and/or solid (coked) form in accordance with Part 1 - Strut Forward Dry Bay Hydraulic Fluid Contamination GVI Inspection at the interval specified in Paragraph 1.E., Compliance. **Part 1 - Strut Forward Dry Bay Hydraulic Fluid Contamination GVI Inspection** 1. Open the thrust reverser. Refer to 777 AMM 78-31-00 as an accepted procedure. 2. Remove the following access panels. Refer to 777 AMM 06-43-00 and 777 AMM 54-53-01 as accepted procedures.
**Strut No. 2 Strut No. 1**  442AR 432AR 3. Do a GVI of the interior of the strut forward dry bay for hydraulic fluid contamination in its liquid (fluid), vapor, and/or solid (coked) form in accordance with the figure below:
**Strut No. 2 Strut No. 1**  FIGURE 4 FIGURE 1 4. Install the following access panels. Refer to 777 AMM 06-43-00 and 777 AMM 54-53-01 as accepted procedures.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 25, 2012 777-54-0028 Revision 1: December 10, 2013 27 of 49 **BOEING SERVICE BULLETIN 777-54-0028 Strut No. 2**  **Strut No. 1** 442AR 432AR 5. Close the thrust reverser. Refer to 777 AMM 78-31-00 as an accepted procedure. 6. Put the airplane back to a serviceable condition. **Part 2 - Strut Forward Dry Bay Interior DET Inspection.** 1. Open the thrust reverser. Refer to 777 AMM 78-31-00 as an accepted procedure. 2. Remove the following access panels. Refer to 777 AMM 06-43-00 and 777 AMM 54-53-01 as accepted procedures.
**Strut No. 2 Strut No. 1**  442AR 432AR 3. Do a DET of the interior of the strut forward dry bay in accordance with the figure below for: 1) Hydraulic fluid coking; and 2) Heat discoloration; and 3) Damage to sealant and primer; and 4) Damage to leveling compound; and 5) Cracks; and 6) Etching or pitting. **NOTE:** It is recommended that operators document contamination with pictures and record the percent of contamination, and whether the lower and/or upper forward engine mount bulkhead fittings are affected to aid in the development of The Boeing Company repair instructions.
**Strut No. 2 Strut No. 1**  FIGURE 5 FIGURE 2
4. Deleted 5. Check drain lines for blockage; Clean or replace drain lines as required. Refer to 777 AMM 54-55-01 as an accepted procedure. 6. Install the following access panels. Refer to 777 AMM 06-43-00 and 777 AMM 54-53-01 as accepted procedures.
**Strut No. 2 Strut No. 1**  442AR 432AR 7. Close the thrust reverser. Refer to 777 AMM 78-31-00 as an accepted procedure. 8. Put the airplane back to a serviceable condition. **Part 3 - Strut Forward Engine Mount Bulkhead Fitting DET and HFEC Inspection** 1. Open the thrust reverser. Refer to 777 AMM 78-31-00 as an accepted procedure.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 25, 2012 777-54-0028 Revision 1: December 10, 2013 28 of 49 **BOEING SERVICE BULLETIN 777-54-0028**2. Remove the following access panels. Refer to 777 AMM 06-43-00 and 777 AMM 54-53-01 as accepted procedures.
**Strut No. 2 Strut No. 1**  442AR 432AR 3. Do a DET and HFEC of the strut forward engine mount bulkhead upper and lower fittings for cracks, and etching or pitting in accordance with the figure below: **NOTE:** It is recommended that operators document contamination with pictures and record the percent of contamination, and whether the lower and/or upper forward engine mount bulkhead fittings are affected to aid in the development of The Boeing Company repair instructions.
**Strut No. 2 Strut No. 1**  FIGURE 6 FIGURE 3
4. Deleted 5. Check drain lines for blockage; Clean or replace drain lines as required. Refer to 777 AMM 54-55-01 as an accepted procedure. 6. Install the following access panels. Refer to 777 AMM 06-43-00 and 777 AMM 54-53-01 as accepted procedures.
**Strut No. 2 Strut No. 1**  442AR 432AR 7. Close the thrust reverser. Refer to 777 AMM 78-31-00 as an accepted procedure. 8. Put the airplane back to a serviceable condition.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 25, 2012 777-54-0028 Revision 1: December 10, 2013 29 of 49 **BOEING SERVICE BULLETIN 777-54-0028 FIGURE 1: STRUT NO. 1 - FORWARD DRY BAY INTERIOR - GVI INSPECTION**  **(SHEET 1 OF 2)**
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 25, 2012 777-54-0028 Revision 1 December 10, 2013 30 of 49 **BOEING SERVICE BULLETIN 777-54-0028**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 one side of the airplane.
**More Data Qty**  **Identification Name**  **Task Step**  Do a General Visual Inspection (GVI) of the interior of the strut forward dry bay for the presence of hydraulic fluid contamination in its liquid (fluid), vapor, and/or solid (coked) form including theside skins and upper chords and web. The interior is painted with primer. Blistered and/or peeling primer is a sign that hydraulic fluid contaminationis present and the strut forward dry bay is contaminated. - - Strut Fwd Dry Bay Inspect 1

**FIGURE 1: STRUT NO. 1 - FORWARD DRY BAY INTERIOR - GVI INSPECTION (SHEET 2 OF 2)** 
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 25, 2012 777-54-0028 Revision 1 December 10, 2013 31 of 49 **BOEING SERVICE BULLETIN 777-54-0028 FIGURE 2: STRUT NO. 1 - FORWARD DRY BAY INTERIOR - DET INSPECTION**  **(SHEET 1 OF 4)**
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 25, 2012 777-54-0028 Revision 1 December 10, 2013 32 of 49 **BOEING SERVICE BULLETIN 777-54-0028**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 one side of the airplane.
**More Data Qty**  **Identification Name**  **Task Step**  Do a DET of the visible areas in the interior of the strut forward dry bay for: 1

- Fwd Engine Mount Bulkhead Upper Fitting Inspect 1 1. Hydraulic fluid coking; and 2. Missing, blistered, peeling or damaged primer; and 3. Heat discoloration; and 4. Cracks; and 5. Etching or pitting. Clean area, as required, to remove loose dirt, peeling primer, and any fluids. Refer to SOPM 20-30-03 as an accepted procedure. Do a DET of the visible areas in the interior of the strut forward dry bay for: 1

- Fwd Engine Mount Bulkhead Lower Fitting Inspect 1. Hydraulic fluid coking; and 2. Missing, blistered, peeling or damaged primer; and 3. Heat discoloration; and 4. Cracks; and 5. Etching or pitting. Clean area, as required, to remove loose dirt, peeling primer, and any fluids. Refer to SOPM 20-30-03 as an accepted procedure. Do a DET for damage. Damage is defined as peeling or disbonding, cracking, and hardeningof the compound. Note: It is normal for the compound to be discolored and stained. - - Leveling Com- pound Inspect 2

**FIGURE 2: STRUT NO. 1 - FORWARD DRY BAY INTERIOR - DET INSPECTION (SHEET 2 OF 4)** 
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 25, 2012 777-54-0028 Revision 1 December 10, 2013 33 of 49 **BOEING SERVICE BULLETIN 777-54-0028 More Data**  **Qty Identification**  **Name Task**  **Step** Do a DET of the visible areas in the interior of the strut forward dry bay for: - - Chord / Web - Low- er Spar Inspect 3 1. Missing, blistered, peeling or damaged primer; and 2. Cracks; and 3. Etching or pitting. Clean area, as required, to remove loose dirt, peeling primer, and any fluids. Refer to SOPM 20-30-03 as an accepted procedure. Do a DET of the visible areas in the interior of the strut forward dry bay for: - - No. 2 Bulkhead Inspect 4 1. Missing, blistered, peeling or damaged primer; and 2. Cracks; and 3. Etching or pitting. Clean area, as required, to remove loose dirt, peeling primer, and any fluids. Refer to SOPM 20-30-03 as an accepted procedure. Do a DET of the visible areas on both sides of the interior of the strut forward dry bay for: - - Side Skin Inspect 5 1. Missing, blistered, peeling or damaged primer; and 2. Cracks; and 3. Etching or pitting. Clean area, as required, to remove loose dirt, peeling primer, and any fluids. Refer to SOPM 20-30-03 as an accepted procedure.

**FIGURE 2: STRUT NO. 1 - FORWARD DRY BAY INTERIOR - DET INSPECTION (SHEET 3 OF 4)** 
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 25, 2012 777-54-0028 Revision 1 December 10, 2013 34 of 49 **BOEING SERVICE BULLETIN 777-54-0028 More Data**  **Qty Identification**  **Name Task**  **Step** Do a DET of the visible areas of the top of the interior of the strut forward dry bay for: - - Chord / Web - Up- per Spar Inspect 6 1. Missing, blistered, peeling or damaged primer; and 2. Cracks; and 3. Etching or pitting. Clean area, as required, to remove loose dirt, peeling primer, and any fluids. Refer to SOPM 20-30-03 as an accepted procedure. Do a DET for damage in the interior of the strut forward dry bay. Sealant damage is defined asbreaks in the sealant, cuts, creases and openings, peeling, or it is missing. - - Sealant Inspect 7

**FIGURE 2: STRUT NO. 1 - FORWARD DRY BAY INTERIOR - DET INSPECTION (SHEET 4 OF 4)** 
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 25, 2012 777-54-0028 Revision 1 December 10, 2013 35 of 49 **BOEING SERVICE BULLETIN 777-54-0028 FIGURE 3: STRUT NO. 1 - FORWARD ENGINE MOUNT BULKHEAD FITTING - DET AND HFEC INSPECTION**  **(SHEET 1 OF 2)**
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 25, 2012 777-54-0028 Revision 1 December 10, 2013 36 of 49 **BOEING SERVICE BULLETIN 777-54-0028**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 one side of the airplane.
**More Data Qty**  **Identification Name**  **Task Step**  Do a DET of the visible areas in the interior of the strut forward dry bay for: 1

- Fwd Engine Mount Bulkhead Upper Fitting Inspect 1 1. Cracks; and 2. Etching or pitting. Clean area, as required, to remove loose dirt, peeling primer, damaged leveling compound, and any fluids. Refer to SOPM 20-30-03 as an accepted procedure. Do a DET of the visible areas in the interior of the strut forward dry bay for: 1

- Fwd Engine Mount Bulkhead Lower Fitting Inspect 1. Cracks; and 2. Etching or pitting. Clean area, as required, to remove loose dirt, peeling primer, and any fluids. Refer to SOPM 20-30-03 as an accepted procedure. Do a HFEC inspection of the accessible areas in the interior of the strut forward dry bay for cracks in the areas where hydraulic fluid coking, heat discoloration, damage to sealant, missing,blistered, peeling or damaged primer, and damage to leveling compound was found, in accordance with 777 NDT Part 6, 51-00-06. 1

- Fwd Engine Mount Bulkhead Upper Fitting Inspect 2

Do a HFEC inspection of the accessible areas in the interior of the strut forward dry bay for cracks in the areas where hydraulic fluid coking, heat discoloration, damage to sealant, missing,blistered, peeling or damaged primer, and damage to leveling compound was found, in accordance with 777 NDT Part 6, 51-00-06. 1

- Fwd Engine Mount Bulkhead Lower Fitting Inspect

**FIGURE 3: STRUT NO. 1 - FORWARD ENGINE MOUNT BULKHEAD FITTING - DET AND HFEC INSPECTION (SHEET 2 OF 2)** 
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 25, 2012 777-54-0028 Revision 1 December 10, 2013 37 of 49 **BOEING SERVICE BULLETIN 777-54-0028 FIGURE 4: STRUT NO. 2 - FORWARD DRY BAY INTERIOR - GVI INSPECTION**  **(SHEET 1 OF 2)**
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 25, 2012 777-54-0028 Revision 1 December 10, 2013 38 of 49 **BOEING SERVICE BULLETIN 777-54-0028**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 one side of the airplane.
**More Data Qty**  **Identification Name**  **Task Step**  Do a General Visual Inspection (GVI) of the interior of the strut forward dry bay for the presence of hydraulic fluid contamination in its liquid (fluid), vapor, and/or solid (coked) form including theside skins and upper chords and web. The interior is painted with primer. Blistered and/or peeling primer is a sign that hydraulic fluid contaminationis present and the strut forward dry bay is contaminated. - - Strut Fwd Dry Bay Inspect 1

**FIGURE 4: STRUT NO. 2 - FORWARD DRY BAY INTERIOR - GVI INSPECTION (SHEET 2 OF 2)** 
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 25, 2012 777-54-0028 Revision 1 December 10, 2013 39 of 49 **BOEING SERVICE BULLETIN 777-54-0028 FIGURE 5: STRUT NO. 2 - FORWARD DRY BAY INTERIOR - DET INSPECTION**  **(SHEET 1 OF 4)**
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 25, 2012 777-54-0028 Revision 1 December 10, 2013 40 of 49 **BOEING SERVICE BULLETIN 777-54-0028**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 one side of the airplane.
**More Data Qty**  **Identification Name**  **Task Step**  Do a DET of the visible areas in the interior of the strut forward dry bay for: 1

- Fwd Engine Mount Bulkhead Upper Fitting Inspect 1 1. Hydraulic fluid coking; and 2. Missing, blistered, peeling or damaged primer; and 3. Heat discoloration; and 4. Cracks; and 5. Etching or pitting. Clean area, as required, to remove loose dirt, peeling primer, and any fluids. Refer to SOPM 20-30-03 as an accepted procedure. Do a DET of the visible areas in the interior of the strut forward dry bay for: 1

- Fwd Engine Mount Bulkhead Lower Fitting Inspect 1. Hydraulic fluid coking; and 2. Missing, blistered, peeling or damaged primer; and 3. Heat discoloration; and 4. Cracks; and 5. Etching or pitting. Clean area, as required, to remove loose dirt, peeling primer, and any fluids. Refer to SOPM 20-30-03 as an accepted procedure. Do a DET for damage. Damage is defined as peeling or disbonding, cracking, and hardeningof the compound. Note: It is normal for the compound to be discolored and stained. - - Leveling Com- pound Inspect 2

**FIGURE 5: STRUT NO. 2 - FORWARD DRY BAY INTERIOR - DET INSPECTION (SHEET 2 OF 4)** 
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 25, 2012 777-54-0028 Revision 1 December 10, 2013 41 of 49 **BOEING SERVICE BULLETIN 777-54-0028 More Data**  **Qty Identification**  **Name Task**  **Step** Do a DET of the visible areas in the interior of the strut forward dry bay for: - - Chord / Web - Low- er Spar Inspect 3 1. Missing, blistered, peeling or damaged primer; and 2. Cracks; and 3. Etching or pitting. Clean area, as required, to remove loose dirt, peeling primer, and any fluids. Refer to SOPM 20-30-03 as an accepted procedure. Do a DET of the visible areas in the interior of the strut forward dry bay for: - - No. 2 Bulkhead Inspect 4 1. Missing, blistered, peeling or damaged primer; and 2. Cracks; and 3. Etching or pitting. Clean area, as required, to remove loose dirt, peeling primer, and any fluids. Refer to SOPM 20-30-03 as an accepted procedure. Do a DET of the visible areas on both sides of the interior of the strut forward dry bay for: - - Side Skin Inspect 5 1. Missing, blistered, peeling or damaged primer; and 2. Cracks; and 3. Etching or pitting. Clean area, as required, to remove loose dirt, peeling primer, and any fluids. Refer to SOPM 20-30-03 as an accepted procedure.

**FIGURE 5: STRUT NO. 2 - FORWARD DRY BAY INTERIOR - DET INSPECTION (SHEET 3 OF 4)** 
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 25, 2012 777-54-0028 Revision 1 December 10, 2013 42 of 49 **BOEING SERVICE BULLETIN 777-54-0028 More Data**  **Qty Identification**  **Name Task**  **Step** Do a DET of the visible areas of the top of the interior of the strut forward dry bay for: - - Chord / Web - Up- per Spar Inspect 6 1. Missing, blistered, peeling or damaged primer; and 2. Cracks; and 3. Etching or pitting. Clean area, as required, to remove loose dirt, peeling primer, and any fluids. Refer to SOPM 20-30-03 as an accepted procedure. Do a DET for damage in the interior of the strut forward dry bay. Sealant damage is defined asbreaks in the sealant, cuts, creases and openings, peeling, or it is missing. - - Sealant Inspect 7

**FIGURE 5: STRUT NO. 2 - FORWARD DRY BAY INTERIOR - DET INSPECTION (SHEET 4 OF 4)** 
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 25, 2012 777-54-0028 Revision 1 December 10, 2013 43 of 49 **BOEING SERVICE BULLETIN 777-54-0028 FIGURE 6: STRUT NO. 2 - FORWARD ENGINE MOUNT BULKHEAD FITTING - DET AND HFEC INSPECTION**  **(SHEET 1 OF 2)**
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 25, 2012 777-54-0028 Revision 1 December 10, 2013 44 of 49 **BOEING SERVICE BULLETIN 777-54-0028**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 one side of the airplane.
**More Data Qty**  **Identification Name**  **Task Step**  Do a DET of the visible areas in the interior of the strut forward dry bay for: 1

- Fwd Engine Mount Bulkhead Upper Fitting Inspect 1 1. Cracks; and 2. Etching or pitting. Clean area, as required, to remove loose dirt, peeling primer, damaged leveling compound, and any fluids. Refer to SOPM 20-30-03 as an accepted procedure. Do a DET of the visible areas in the interior of the strut forward dry bay for: 1

- Fwd Engine Mount Bulkhead Lower Fitting Inspect 1. Cracks; and 2. Etching or pitting. Clean area, as required, to remove loose dirt, peeling primer, and any fluids. Refer to SOPM 20-30-03 as an accepted procedure. Do a HFEC inspection of the accessible areas in the interior of the strut forward dry bay for cracks in the areas where hydraulic fluid coking, heat discoloration, damage to sealant, missing,blistered, peeling or damaged primer, and damage to leveling compound was found, in accordance with 777 NDT Part 6, 51-00-06. 1

- Fwd Engine Mount Bulkhead Upper Fitting Inspect 2

Do a HFEC inspection of the accessible areas in the interior of the strut forward dry bay for cracks in the areas where hydraulic fluid coking, heat discoloration, damage to sealant, missing,blistered, peeling or damaged primer, and damage to leveling compound was found, in accordance with 777 NDT Part 6, 51-00-06. 1

- Fwd Engine Mount Bulkhead Lower Fitting Inspect

**FIGURE 6: STRUT NO. 2 - FORWARD ENGINE MOUNT BULKHEAD FITTING - DET AND HFEC INSPECTION (SHEET 2 OF 2)** 
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 25, 2012 777-54-0028 Revision 1 December 10, 2013 45 of 49 **BOEING SERVICE BULLETIN 777-54-0028 APPENDIX A: CLEANING AND REFINISHING OF STRUT FWD DRY BAY DETAILS**  **(SHEET 1 OF 4)**
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 25, 2012 777-54-0028 Revision 1 December 10, 2013 46 of 49 **BOEING SERVICE BULLETIN 777-54-0028 APPENDIX A: CLEANING AND REFINISHING OF STRUT FWD DRY BAY DETAILS**  **(SHEET 2 OF 4)**
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 25, 2012 777-54-0028 Revision 1 December 10, 2013 47 of 49 **BOEING SERVICE BULLETIN 777-54-0028**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 one side of the airplane. **NOTE:** When cleaning, do not use solvents which contain chlorinated hydrocarbons. This can result in hydrogen embrittlement of the titanium parts when the parts enter service and are exposed to heat. Refer to SOPM 20-30-03 as an accepted procedure. 1.

2. If leveling compound is being applied, level airplane. Refer to 777 AMM 08-21-00 as an accepted procedure. Leveling the airplane is not required if repairing small damaged areas, 1 square inch or less, with sealant.
**More Data Qty**  **Identification Name**  **Task Step**  Not Shown. Solvent clean the interior of surfaces of the strut forward dry bay area, as required. Refer to SOPM 20-30- 03 as an accepted procedure. - - Strut Fwd Dry Bay Clean 1

To the aluminum No. 2 Bulkhead Assembly and the Side Skins only. Refer to SOPM 20-43-03, Type 2, class A as an accepted procedure. - - Chemical Conver- sion Coating Apply 2

Apply one coat. Cure at room temperature. - SOPM 20-44-01, Type 51Primer, High Temperature Apply 3 Apply two coats. Upper spar chord and web. BMS 10-11, TYPE I Primer Apply 4 Apply one coat. Side skin. BMS 10-79, TYPE III Primer Apply 5 Restore fillet seals as required.

- BMS 5-63 Sealant Apply 6 Remove damaged leveling compound.

- - Leveling Com- pound Remove 7 Apply primer to the bare surfaces where leveling compound will be applied. Thiswill ensure proper adhesion of the leveling compound. Not required if doing optional sealant repair in step applying the leveling compound below. - BAC 5432, COM- POUND 21, DOW CORNING 1201 RTV PRIME COAT (DOW CORNING PR-1200 RTV PRIME COATRED OR SS4004P optional) Primer, Silicone Apply

**APPENDIX A: CLEANING AND REFINISHING OF STRUT FWD DRY BAY DETAILS (SHEET 3 OF 4)** 
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 25, 2012 777-54-0028 Revision 1 December 10, 2013 48 of 49 **BOEING SERVICE BULLETIN 777-54-0028 More Data**  **Qty Identification**  **Name Task**  **Step** Mix with catalyst in accordance with the manufacturer's instructions to form the leveling compound. Not required if doing optional sealant repair in step applying the leveling compound below. - BAC 5432, COM-POUND 21, COMPOUND 21, XIAMETER RTV-3110 BASE (DC 3110 OR RTV11 optional)Leveling Compound, Silicone Make 8

Mix with silicone in accordance with the manufacturer's instructions to form the leveling compound. Not required if doing optional sealant repair in step applying the leveling compound below. - BAC 5432, COM-POUND 21, XIAMETER RTV-3010-S CATALYST (XIAMETERRTV-3000 F CATALYST, S TIN NW, OR RTV9950 optional) Catalyst Make

Pour the leveling compound into the forward corners, until it is level with the bottom of the fitting or drain hole. Do not block drain hole. Not required if doing optional sealant repair below. - - Leveling Com- pound Apply 9

Optional for areas that are 1 square inch or less. Leveling airplane is not required if using this method. Smooth into existing leveling compound.

- BMS 5-63 Sealant Apply

**APPENDIX A: CLEANING AND REFINISHING OF STRUT FWD DRY BAY DETAILS (SHEET 4 OF 4)** 
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 25, 2012 777-54-0028 Revision 1 December 10, 2013 49 of 49 **BOEING SERVICE BULLETIN 777-54-0028**