### Commercial **Airplanes** 

# 777 Service Bulletin **SPECIAL ATTENTION Number: 777-54-0028**  Original Issue: May 25, 2012 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 Unpublished Work.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, DreamlinerTM, BBJ, DC-8, DC-9, DC-10, KC-10, KDC-10, MD-10, MD-11, MD-80, MD-88, MD-90, P-8A, Poseidon and 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. BOEING is a trademark of Boeing Management Company.

Original Issue: May 25, 2012 777-54-0028 1 of 42 4.0Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 25, 2012 777-54-0028 2 of 42 **BOEING SERVICE BULLETIN 777-54-0028**

BLANK PAGE**Table of Contents** Summary...................................................... 5 1. PLANNING INFORMATION ........................................ 9 A. Effectivity................................................ 9 1. Airplanes............................................. 9 2. Spares Affected . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 B. Concurrent Requirements. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 C. Reason . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 D. Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 E. Compliance. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 F. Approval . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 G. Manpower . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 H. Weight and Balance Changes. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 I. Electrical Load Data. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 J. References. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 1. Existing Data: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 2. Data Supplied with this Service Bulletin:. . . . . . . . . . . . . . . . . . . . . . . . . . . 16 3. Installation Drawings Used in the Preparation of this Service Bulletin:. . . . . . . . . . . 16 K. Publications Affected . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 L. Interchangeability and Intermixability of Parts. . . . . . . . . . . . . . . . . . . . . . . . . . . 16 M. Software Accomplishment Summary. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 2. MATERIAL INFORMATION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 A. Material - Price and Availability. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 B. Industry Support Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 C. Parts Necessary for Each Airplane. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 1. Kits/Parts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 2. Parts and Materials Supplied by the Operator. . . . . . . . . . . . . . . . . . . . . . . . 17 3. Parts Modified and Reidentified. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 4. Parts Removed and Not Replaced. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 D. Parts Necessary to Change Spares. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 E. Special Tooling - Price and Availability. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 F. Special Tooling Necessary to do this Service Bulletin. . . . . . . . . . . . . . . . . . . . . . . 18 3. ACCOMPLISHMENT INSTRUCTIONS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 A. GENERAL INFORMATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 B. WORK INSTRUCTIONS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 FIGURE 1: STRUT NO. 1 - FORWARD DRY BAY INTERIOR - GVI INSPECTION. . . . . . . . . . . 24 FIGURE 2: STRUT NO. 1 - FORWARD DRY BAY INTERIOR - DET INSPECTION . . . . . . . . . . 26 FIGURE 3: STRUT NO. 1 - FORWARD ENGINE MOUNT BULKHEAD FITTING - DET AND HFEC INSPECTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 FIGURE 4: STRUT NO. 2 - FORWARD DRY BAY INTERIOR - GVI INSPECTION. . . . . . . . . . . 32 FIGURE 5: STRUT NO. 2 - FORWARD DRY BAY INTERIOR - DET INSPECTION . . . . . . . . . . 34 FIGURE 6: STRUT NO. 2 - FORWARD ENGINE MOUNT BULKHEAD FITTING - DET AND HFEC INSPECTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38 APPENDIX A: CLEANING AND REFINISHING OF STRUT FWD DRY BAY DETAILS . . . . . . . . . . 40

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 25, 2012 777-54-0028 3 of 42 **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 4 of 42 **BOEING SERVICE BULLETIN 777-54-0028**

BLANK PAGE

### Commercial **Airplanes** 

# 777 Service Bulletin **SPECIAL ATTENTION Summary**  **Number: 777-54-0028** Original Issue: May 25, 2012 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 of the strut forward dry bay, before the forward engine mount bulkhead fittings becomes sufficiently hydrogen embrittled that it can not carry design loads. If hydraulic fluid 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 the 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 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 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 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.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 25, 2012 777-54-0028 5 of 42This 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. 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. **EFFECTIVITY** 777-200 and -300 Airplanes powered by PW4000 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: May 25, 2012 777-54-0028 6 of 42 **BOEING SERVICE BULLETIN 777-54-0028 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 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 7 of 42 **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 8 of 42 **BOEING SERVICE BULLETIN 777-54-0028**

### Commercial **Airplanes** 

# 777 Service Bulletin **SPECIAL ATTENTION Number: 777-54-0028**  Original Issue: May 25, 2012 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

Airplane Models: 777-200, 777-300 **Group Variable Number**  1 WA002 - WA017 1 WA131 - WA137 1 WA171 - WA175 1 WA206 - WA212 1 WA221 - WA223 1 WA231 - WA232 1 WA241 - WA250 1 WA261 - WA266

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 25, 2012 777-54-0028 9 of 42**Group Variable Number**  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 1 WC591 - WC592 2. Spares Affected None. **B. Concurrent Requirements** None. **C. Reason** Accomplishment of the inspections in this service bulletin will find hydraulic fluid contamination of the strut forward dry bay, before the forward engine mount bulkhead fittings becomes sufficiently hydrogen embrittled that it can not carry design loads. If hydraulic fluid 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 the 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.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 25, 2012 777-54-0028 10 of 42 **BOEING SERVICE BULLETIN 777-54-0028**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 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 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 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. **D. Description** 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. 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. The work in this service bulletin is done in the maintenance zone(s) given below.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 25, 2012 777-54-0028 11 of 42 **BOEING SERVICE BULLETIN 777-54-0028 Affected Maintenance Zones**  **Zone Model**  432, 442 777-200, 777-300 **E. Compliance** The Federal Aviation Administration (FAA) will possibly release an Airworthiness Directive related to this service bulletin. The Airworthiness Directive will make the compliance tasks and times given in this service bulletin mandatory. 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 original issue date of this service bulletin, whichever occurs first. Do a GVI of the interior of thestrut forward dry bay for hydraulic fluid contamination in accordance with Part 1. All Airplanes

1,200 Flight-cycles. - Repeat GVI of the interior of thestrut forward dry bay for hydraulic fluid contamination in accordance with Part 1. Condition 1 - No hydraulic fluid contamination 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 is found.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 25, 2012 777-54-0028 12 of 42 **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 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. Contact The Boeing Company for repair instructions and do the repair. ....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 accordance with Part 1.

- Before further flight. Contact The Boeing Company for repair instructions and do the repair. 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 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 13 of 42 **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. **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 4.00 4.00 1 ...FIGURE 2 4.00 4.00 1 ...FIGURE 5 2.50 5.00 2 Check Drain Line

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 25, 2012 777-54-0028 14 of 42 **BOEING SERVICE BULLETIN 777-54-0028 Part 2 - Strut Forward Dry Bay Interior DET Inspection**  **Elapsed Hours Task Hours**  **Number of Persons Task**  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. Service Bulletin Index D624W001 d. Standard Overhaul Practices Manual (SOPM) 20-30-03, 20-43-03, 20-44-01 e. Standard Wiring Practices Manual (SWPM) 20-10-11, 20-10-12, 20-10-19 f. 777 Aircraft Maintenance Manual (AMM) 06-43-00, 08-21-00, 54-53-01, 54-55-01, 78-31-00 g. 777 Fleet Team Digest (FTD) 54-11001 h. 777 Non-Destructive Testing (NDT) Manual Part 6, 51-00-06

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 25, 2012 777-54-0028 15 of 42 **BOEING SERVICE BULLETIN 777-54-0028**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 16 of 42 **BOEING SERVICE BULLETIN 777-54-0028 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 finishes to 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) (e) Primer, Silicone 1 Pt. BAC 5432, COMPOUND 21 (DC1200 OR SS4004P01 P) (d) (e) Leveling Compound, Silicone 2 Qt. BAC 5432, COMPOUND 21 (DC3110 OR RTV11) (d) (e) Catalyst 1 Pt. BAC 5432, COMPOUND 21 (S TIN NW OR RTV9950) (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. (c) Refer to SOPM 20-43-03 for supplier data. (d) DC 3110 (Leveling Compound), S TIN NW (Catalyst), and DC1200 (Primer); V71984; DowCorning Corporation, 2200 W Salzburg Rd, Midland Mi 48640 - 8531; Customer Service/www.dowcorning.com; (800) 248-2481

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 25, 2012 777-54-0028 17 of 42 **BOEING SERVICE BULLETIN 777-54-0028 Notes**  **Name QTY**  **Part Number / Specification**(e) 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 18 of 42 **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 19 of 42 **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 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 is found. (1) Repeat GVI of the interior of the strut forward dry bay for hydraulic fluid contamination 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 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 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. 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

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 25, 2012 777-54-0028 20 of 42 **BOEING SERVICE BULLETIN 777-54-0028**2) Contact The Boeing Company for repair instructions and do the repair at the compliance time specified in Paragraph 1.E., Compliance; and 3) Repeat GVI of the interior of the strut forward dry bay for hydraulic fluid contamination 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 and do the repair at the compliance time specified in Paragraph 1.E., Compliance; and 2) Repeat GVI of the interior of the strut forward dry bay for hydraulic fluid contamination 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 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.
**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.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 25, 2012 777-54-0028 21 of 42 **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 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. Clean and restore sealant, primer, and leveling compound of the detail parts in the strut forward dry bay if missing, blistered, peeling, or damaged. Refer to APPENDIX A as an accepted procedure. If leveling compound is being applied, level airplane. Refer to 777 AMM 08-21-00 as an accepted procedure. 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. 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:

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 25, 2012 777-54-0028 22 of 42 **BOEING SERVICE BULLETIN 777-54-0028 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. Clean and restore sealant, primer, and leveling compound of the detail parts in the strut forward dry bay if missing, blistered, peeling, or damaged. Refer to APPENDIX A as an accepted procedure. If leveling compound is being applied, level airplane. Refer to 777 AMM 08-21-00 as an accepted procedure. 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 23 of 42 **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 24 of 42 **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, including the side skins and upper chords and web. The interior is painted with primer. Blistered and/or peeling primer is a sign that hydraulic fluid is or has been 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 25 of 42 **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 26 of 42 **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 27 of 42 **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 28 of 42 **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 29 of 42 **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 30 of 42 **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 31 of 42 **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 32 of 42 **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, including the side skins and upper chords and web. The interior is painted with primer. Blistered and/or peeling primer is a sign that hydraulic fluid is or has been 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 33 of 42 **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 34 of 42 **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 35 of 42 **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 36 of 42 **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 37 of 42 **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 38 of 42 **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 39 of 42 **BOEING SERVICE BULLETIN 777-54-0028 APPENDIX A: CLEANING AND REFINISHING OF STRUT FWD DRY BAY DETAILS**  **(SHEET 1 OF 3)**
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 25, 2012 777-54-0028 40 of 42 **BOEING SERVICE BULLETIN 777-54-0028 APPENDIX A: CLEANING AND REFINISHING OF STRUT FWD DRY BAY DETAILS**  **(SHEET 2 OF 3)**
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 25, 2012 777-54-0028 41 of 42 **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.
**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 to the areas where leveling compound will be applied. This will ensure proper adhesion of the leveling compound. - BAC 5432, COM- POUND 21 (DC1200 OR SS4004P01 P) Primer, Silicone Apply 7

Mix with catalyst in accordance with the manufacturer's instructions to form the leveling compound. - BAC 5432, COM- POUND 21 (DC3110 OR RTV11)Leveling Compound, Silicone Make 8

Mix with silicone in accordance with the manufacturer's instructions to form the leveling compound. - BAC 5432, COM- POUND 21 (S TIN NW OR RTV9950) 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. - - Leveling Com- pound Apply 9

**APPENDIX A: CLEANING AND REFINISHING OF STRUT FWD DRY BAY DETAILS (SHEET 3 OF 3)** 
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 25, 2012 777-54-0028 42 of 42 **BOEING SERVICE BULLETIN 777-54-0028**